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Along with the continuous development of agricultural aviation application technology, an agricultural unmanned aerial vehicle (UAV) is widely used in modern agricultural production, which is the operation platform for implementing agricultural aviation technology. Due to the characteristics of simple operation, simple structure, easy maintenance and low cost, electric multi-rotor UAV is widely used in the field of agricultural aviation. However, it has the problems of small load capacity, short continuous operation time, low operation efficiency, etc. The multi-rotor single-arm tandem structure can effectively improve the load capacity and operation capacity of the electric UAV, but the structure will lead to the increase of the size and mass of the whole machine and reduce the effective utilization rate of energy, which still needs to be optimized and improved. Rotor spacing affects the overall performance of multi-rotor single-arm tandem electric UAV, but the influence of different rotor spacing on rotor lift of multi-rotor single-arm structure has not been studied. In this paper, by setting up a test platform and taking power consumption (P) and lift (F) as test indexes, the rotors with different spacing were tested, and the optimal spacing ratio between tandem rotors was analyzed and determined. The optimal spacing ratio was verified by theoretical analysis and flight test of solid aircraft. The lift performance and energy consumption of coaxial and tandem twin rotors at different spacing were tested. The results showed that the longitudinal spacing ratio had no effect on the lift performance, while the lateral spacing ratio had an effect on the lift performance. In order to further determine the optimal lateral spacing ratio, the variation law of rotor lift with lateral spacing ratio under the double rotor tandem arrangement was tested. When the lateral spacing ratio was less than 1.8, the lower rotor lift increased with the increase of lateral spacing ratio under the same power consumption. When the lateral spacing ratio was greater than 1.8, the lift of the lower rotor tended to be stable, and the average value of the lower rotor lift relative to the loss percentage of the isolated rotor was stable within 0.70%. When the lateral spacing ratio was equal to 1.8, the average loss percentage of the rotor lift under the tandem layout was 0.66% relative to the isolated rotor lift under different power consumption. At this time, the lower rotor lift is basically the same as the isolated rotor lift, thus determining that the optimal spacing ratio of the tandem double rotor was equal to 1.8. Secondly, by testing the variation of the lift force of two rotors with different sizes and the rotor lift force with the lateral spacing ratio under the tandem layout of multiple rotors, it was concluded that 1.8 was suitable for the tandem layout mechanism with different sizes and number of rotors. In order to validate the optimal effect of the lateral spacing ratio of 1.8 on the rotor spacing of the multi-rotor single-arm tandem electric UAV, this paper compared and analyzed the performance parameters of planar and tandem aircraft of six-axis 12-rotor UAV with multi-rotor single-arm structure. The results showed that compared with the tandem model with lateral spacing ratio 1.8, the fuselage size of the planar model increases by 38.70%, while the lift difference between the two is only 1.52%. Through flight tests, the results showed that under the same load, the hovering power per unit time of the planar model decreased by only 0.06%, while the fuselage mass increased by 6.82% compared with the optimized tandem model, the fuselage size increased by 38.7%. This paper studied the optimal rotor spacing of multi-rotor single-arm electric UAV. On the premise of ensuring the energy efficiency of the UAV, the rotor spacing of the multi-rotor single-arm structure electric UAV is optimized by changing the relative positions between the rotors, so as to optimize the fuselage size and mass, improve the aerodynamic characteristics of the multi-rotor single-arm structure UAV, reduce inertia, enhance payload capacity, and thus improve the overall performance. [ABSTRACT FROM AUTHOR]

Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots, leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots (each plots is 30 m×0.76 m), leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

Grain loss rate is one of the most important performance index of corn head in mechanized harvesting. Seed harvesting is the main development direction of mechanized corn harvesting. The characters of seed harvesting corn variaty increased the urgency to reduce grain loss on corn head. The paper was proposed to solve the problem of grain loss on corn head. Theoretical analysis was conducted to the snapping process. Corn ear was subjected to pull force by the snapping rolls and the pull force transferred by corn stalk. Corn kernels were divided into 2 types due to their force condition. A kernel at the bottom end of corn ear was subjected to reaction forces by stripper plates, corn cob and the adjacent kernels and shear force by the pedicel. Kernels out of contact with the stripper plates were subjected to reaction forces by the adjacent kernels, pull force and shear force by corn cob. As the impact force was related to the impact time according to the theorem of impulse, the paper analyzed collision model between corn ear and stripper plates in the snapping process. A mathematical model was obtained about the impact time and intrinsic parameters of the system. The impact time was dependent on system mass, stiffness coefficient and damping coefficient, which lays on the mechanical structure and materials of collision objects. So, the impact force would decrease as the impact time could be prolonged by reducing the stiffness coefficient and raising the damping coefficient. The quantity of shed kernels could be reduced consequently. The paper proposed a corn head with wheel type rigid-flexible coupling snapping device to reduce loss. The corn head consisted of the frame, gear-box, snapping rolls, gathering chain, wheel type rigid-flexible coupling snapping device, and chain wheels. The wheel type rigid-flexible coupling snapping device consisted of snapping wheel axle, spring seat axle, supporting axle, buffer spring, and snapping wheel frame. Force analysis was conducted on the snapping wheel. According to the force conditions and dimension boundary condition, the structure diameters of snapping wheel, snapping wheel frame, and buffer spring were confirmed. In order to obtain the optimal parameters with the minimum loss rate of wheel type rigid-flexible coupling snapping device, the optimization experiments were conducted of the factors at 3 different levels. In the optimization experiments, the snapping wheel radius was designed at 10, 15 and 20 mm respectively, the flexible body thickness was at 2, 4 and 6 mm respectively, the snapping rolls rotating speed at 700, 800 and 900 r/min respectively. The Response Surface Analysis method was used to design the experiments. The software Design-Expert 8.0.6.1 was used to analyze the data. Regression equation was induced according to the experiment and analysis above. The optimal combination of wheel type coupling snapping device was as follows: The snapping rolls rotating speed was 700 r/min, the snapping wheel radius was 15 mm, the flexible body thickness was 4 mm. Verification contrast test was conducted between corn head with wheel type rigid-flexible coupling snapping device and the one with snapping rolls and stripper plates on corns at different moisture contents. As the kernels moisture contents were 21.8%, 16.7% and 13.4%, the grain loss rate decreased 53.4%, 48.6% and 47.0% respectively. This study provides not only theoretical basis but also design reference for the improvement of corn harvester design. [ABSTRACT FROM AUTHOR]

4HLB-4 type semi-feeding four-row peanut combine harvester gets 2 ridges (4 rows) at one time, whose productive efficiency is 2 times more than the existing semi-feeding two-row peanut combine harvester. Bar strip screen, woven screen and perforated screen and other traditional screens are widely used in semi-feeding peanut combine harvesting, but in practice, it is found that the traditional screens can not meet the demand of changeable soil moisture content and the requirement of high efficiency. In the application of semi-feeding four-row peanut combine harvester, there are many problems such as high percentages of impurities and loss, and debris blockage. In order to overcome the above difficulties, a stacked elastic steel pole oscillating screen was designed in this paper, and it can transfer dynamic load to the elastic steel pole to motivate elastic vibration of itself, which has a very good breaking and flipping effect on the mixture of peanut and varia on the screen surface and is good for screening operation and improves screening quality and speed effectively. In this paper, the percentages of impurities and loss were taken as the evaluation indices, and the contrast tests for 3 kinds of traditional screens (bar strip screen, woven screen and perforated screen) and elastic steel pole oscillating screen were carried out when the operating speed was 0.8, 1.0 and 1.2 m/s respectively. The test results showed that cleaning effect of elastic steel pole oscillating screen was better than the other 3 traditional screens in 3 operation speeds. Based on the single factor experiment, vibration frequency of elastic pole screen, diameter of elastic pole, altitude of elastic pole screen, mounting angle were selected as influencing factors. The four-factor three-level quadratic regression orthogonal test was carried out by using Box-Benhnken central composite test method. Two polynomial regression models about percentage of impurities and percentage of loss v.s. the 4 variables including vibration frequency of elastic pole screen, diameter of elastic pole, altitude of elastic pole screen, and mounting angle were established. Response surface methodology was used to analyze the influence of various factors on percentages of impurities and loss, and the influence factors were optimized. The experimental results showed that different factors and their interactions had different influence on the measured indices. The significant sequence for percentage of impurities was vibration frequency of elastic pole screen > diameter of elastic pole > altitude of elastic pole screen > mounting angle. The significant sequence for percentage of loss was altitude of elastic pole screen > mounting angle > vibration frequency of elastic pole screen > diameter of elastic pole. In order to find the best combination of parameters, the minimum percentages of impurities and loss were taken as optimization targets, a research on parameter optimization of the screen was carried out, and the constraint condition of objective function and parameter variable was established. The optimal parameter combination of vibration frequency of elastic pole screen of 6 Hz, diameter of elastic pole of 3 mm, altitude of elastic pole screen of 7 mm and mounting angle of 2.8° was obtained using optimization module of Design-Expert data analysis software. Field experiments were carried out with the above optimized parameters, and the percentage of impurities was 2.41% and the percentage of loss was 0.711%. The relative errors of each evaluation index and its theoretical optimization value were less than 5%. The research results can provide references for the perfect design and operation parameter optimization of 4HLB-4 type semi-feeding four-row peanut combine harvester and cleaning component. [ABSTRACT FROM AUTHOR]

Sweet potato is an important food crop and energy crop. In order to solve the problems of larger loss rate and high damage rate of 4UZL-1 sweet potato combine harvester during the operation process, a potato connection and conveying mechanism was designed based on the analysis of the structure of 4UZL-1 sweet potato combine harvester and characteristics of domestic sweet potato planting models in this paper. The potato connection and conveying mechanism was mainly composed of a depth limiting mechanism, a digging conveying mechanism, an arc grid conveying mechanism and a scraper chain conveying mechanism. The working parameters were obtained through the kinematic and mechanical analysis of the working process of the mechanism. Aiming at the main evaluation indexes of potato damage rate and loss rate during the transfer and transportation, the Box-Benhnken test was presented on the basis of single-factor test. The angle of the digging conveyor, the conveyor angle of the scraper chain, the conveyor speed of the digging and the conveyor speed of the scraper chain were selected as testing factors. The multiple regression model of evaluation index to each factor was established, and the influence of each factor on operation quality was analyzed, and the optimal structure and operation parameters were obtained. The results showed that the order of the significance influence of factors on potato loss rate from large to small was that the conveyor angle of the scraper chain, the conveyor speed of the digging conveyor, the conveyor speed of the scraper chain and the angle of the digging conveyor. The order of the factors influencing on potato damage rate from large to small was the conveyor speed of the digging, the angle of the digging conveyor, the conveyor speed of the scraper chain and the conveyor angle of the scraper chain. When the forward speed of the machine was 1 m/s, the angle of the digging conveyor was 20°, the conveyor angle of the scraper chain was 68°, the conveyor speed of the digging was 1.2 m/s, and the conveyor speed of the scraper chain was 0.67 m/s, respectively, the potato loss rate was 1.12%, and the potato damage rate was 0.94%. Compared with the predicted values, the relative errors were 3.4% and 1.1%, respectively, the results satisfied the performance requirements of the 4UZL-1 sweet potato combine harvester. The study is benefit for the structure improvement and operation parameters optimization of the sweet potato combine harvester. [ABSTRACT FROM AUTHOR]

To solve the problems of low removal rate and incomplete separation for the current longitudinal-axial-flow combined harvester in the case of harvesting rice and wheat, a segmented longitudinal-axial-flow threshing device was designed in this paper. The threshing device mainly comprised a tapered threshing roller, a concave sieve with adjustable threshing strength, a 360° separation device and an electric control system for operating parameters. Through the single factor tests, the optimal switching states of the concave sieve with adjustable threshing strength for rice and wheat threshing was obtained respectively. In order to find out the influence rule of the working parameters of the device on the threshing effects and the optimal parameter combination, the multi-objective optimization tests were carried out. The rotational speed of roller, the angle of deflector, the threshing gap of concave sieve, the separation gap of concave sieve and the feeding rate were selected as the influence factors and the crushing rate, impurity rate and loss rate were selected as the test indexes. The test results showed that the significant sequence of influence of threshing parameters on the crushing rate was the rotational speed of roller, the threshing gap of concave sieve, the angle of deflector, the feeding rate, the separation gap of concave sieve. The significant sequence of influence of threshing parameters on impurity rate was the rotational speed of roller, the angle of deflector, the threshing gap of concave sieve, the feeding rate, the separation gap of concave sieve. The significant sequence of influence of threshing parameters on loss rate was the rotational speed of roller, the angle of deflector, the threshing gap of concave sieve, the feeding rate, the separation gap of concave sieve. Through multi-objective parameter optimization analysis, the optimal working parameters combination for wheat threshing were determined that the rotational speed of roller was 905 r/min, the angle of deflector was 69°, the threshing gap of concave sieve was 18 mm, the separation gap of concave sieve was 19 mm and the feeding rate was 4 kg/s. The field verification tests were carried out using the optimal working parameters combination. The results indicated that the crushing rate was reduced from 1.46% to 1.00%, the impurity rate was reduced from 1.85% to 1.43% and the loss rate was reduced from 1.72% to 1.20% compared with the conventional longitudinal-axial-flow threshing device. All the relative errors between the measured values and the optimized values were less than 5%, the working indicators met the requirements of relevant national standards. The device effectively solved the problems of high crushing rate, unclean threshing and incomplete separation, the research results can provide reference for the structural improvement and operation parameters optimization of the threshing device of longitudinal-axial-flow combined harvester. [ABSTRACT FROM AUTHOR]

There are a lot of blind application of chemical fertilizers in the planting of bananas, which leading to waste of fertilizers and environmental pollution. According to the distribution pattern of banana root system, a variable fertilizer apparatus was designed in this paper. Based on the image processing of banana root morphology and the statistics of the area area pixels, the distribution pattern of the banana root system in the horizontal direction was analyzed. Based on the characteristics of the root area distribution, the change of fertilization amount along with the root distribution in horizontal was normally distributed, that is, the amount of fertilizer in the main root was the largest. Based on this, a rotary plate variable fertilizer apparatus was designed. By calculating the fertilizer amount distribution discharged on the simulated ground by the simulated fertilizer discharger, it was determined that the distribution law of the fertilizer amount along the forward direction of the machine was also normally, which was the same with the banana root distribution. In order to ensure that the fertilizer discharging amount and the center position of the normal distribution of the root are consistent in space, taking the spatial consistency of the center positions of the two normal distribution as the goal, the operation process planning was carried out for the image acquisition interval time, algorithm time, motor response time, fertilizer falling time, etc., and the accompanying operation control model of the machines was established. The variable control system was used to achieve and ensure that the center positions of the two normal distributions were consistent in space. The center combination simulation test was carried out with the movement speed, the moving period of the rotating plate, the central angle of curved slot and the opening size of curved slot as independent variables, and the length of fertilizer distributing and the fertilizer discharge amount were used as test response values. The result of optimal parameter combination was that the movement speed is 0.25 m/s, moving period of the rotating plate is 10.00 s, the central angle of curved slot is 90.00°, and the opening size of curved slot is 20.00 mm. The model and test errors, simulation and test errors of the length of fertilizer discharge are 4.98% and 3.30% respectively, the model and test error, simulation and test error of fertilizer discharge amount are 11.15% and 6.68%, respectively. The field test was conducted to examine the field operation effect of the fertilizer discharger, the average qualified rate of fertilizer discharging length was 96%, the average qualified rate of fertilizer discharge amount was 95.33%，the operation performance of fertilizer apparatus was good. [ABSTRACT FROM AUTHOR]

Mechanical precision seed metering device is widely used in precision seeding technology because of its simple structure and uniform seed metering. Seed filling process is the key link of the whole operation process of seed metering device. The precision metering device is mainly divided into internal filling, side filling, external filling, and the combination of side filling and external filling according to the seed filling mode. In the operation process, the internal filling mode mainly completes the seeding operation through the process of type-hole filling and gravity clearing, and the seed motion parameters close to the type-hole directly affect the seeding quality of the machine. The rotary type-hole cotton precision seed metering device is a kind of mechanical precision seed metering device. In order to solve the problem of missing seed in the process of filling, the influence of the motion parameters of rotary type-hole cotton precision seed metering device on the filling performance by establishing the kinematic model of the seed filling process in this paper. Using the discrete element simulation software to analyze the speed change trend of cotton seed falling into the type-hole and the influence of seed wheel vibration frequency on seed group disturbance. Taking the vibration frequency of seed wheel, vibration offset angle of seed wheel and rotating speed of metering device as the test factors, and taking the qualified rate of seed spacing, replaying rate and missing rate as the test indexes, three factors and five levels of positive traffic rotation combined test are carried out to explore the influence of each factor on seed metering performance. Design expert 8.0.6 software is used to analyze the test results and optimize the regression model. Single factor simulation test results show that the instantaneous speed of cotton seed increases with the increase of the rotating speed of the seed wheel, the instantaneous speed of the cotton seed is less than that of the seed wheel when it is filled into the type-hole, the cotton seeds with lower relative speed have better filling effect. When the vibration frequency of the seed wheel is 7 Hz, the average value of the normal force of the seed group is the smallest, which is 0.75 N, at this time, the internal friction of the seed goup is the smallest, the cotton seed is easy to be taken by the type-hole, and the seed filling performance of the seed metering device is improved. The simulation results of quadratic regression general rotation combination show that when the rotating speed of the seed metering device is 12.59 r/min, the vibration offset angle of seed wheel is 8.06° and the vibration frequency of seed wheel is 6.08 Hz, the qualified rate of seed spacing reaches the maximum of 94.5%, and the leak seeding rate is 2.9%, the repaly rate is 3.3%. On this basis, the platform validation test was carried out with Xinluzao No.61 cotton seed as the test object. The test results showed that when the rotating speed of the seed metering device was 12 r/min, the maximum qualified rate of the seed spacing was 94.65%, the error between the rotating speed of the seed metering device and the simulation test is 5.4%, which verifies the accuracy of the simulation results. This study can provide a reference for the structural optimization of the key components of the rotary type-hole cotton precision metering device. [ABSTRACT FROM AUTHOR]

In modern agricultural production, the arched shed is more and more widely used in vegetable cultivation and seedling breeding. The arched shed is mainly built by manual. At present, the agricultural demand of arched shed width is about 0.8-1.5 m, and the height of arched shed is about 0.4-1 m. In order to improve the mechanization and automation level and the efficiency in the process of building arched shed, automatic cuttage device of arched shed was designed in this paper. Automatic cuttage device of arched shed was mainly composed of hydraulic transmission system, arm bending, crank slide mechanism, and tent pole cuttage mechanism. The hydraulic transmission system was the power source of the device. According to the technical requirements of building the arched shed and the conditions for the existence of crank, the structural optimization design of the crank slider mechanism was carried out, which was the critical component of automatic cuttage device of arched shed. When the length of the crank was 230 mm, the length of the connecting rod was 220 mm, and the eccentricity was 220 mm, the best force transmission effect and the movement efficiency were achieved. In addition,, the motion analysis of the crank slider mechanism was carried out. The initial angle and the maximum position angle of the crank were determined as 132° and 30°, respectively. The bending arm was designed to bend the shed rod, and at the same time to ensure that the shed rod vertical into the soil. The stress analysis of the rod in the initial state was simulated with different place of application of force, which is the different distance between the end of the bending platen and both ends of the rod. The closer this distance is, the greater the deformation will be. Therefore, the total bending arm length was set to be 44 cm, of which the length of bending platen was 7 cm. The thin and soft skeleton of the arched shed was covered with a flexible plastic film on the outside of the structure, which is more sensitive to the wind load. It is particularly important to ensure the wind resistance of the arch canopy. The wind resistance of small arch shed was analyzed by ANSYS, and it was found that the wind resistance of arched shed was the best when the ratio of frame width to frame length was between 0.60-0.66. The key parameters such as the height of the roof from the top of the shed, the width of arbor and the depth of shed insert soil were measured. The average buried depth was 15.23 cm, and the stability coefficient was 97.86%. The average height and width of the tunnel were 56.19 cm and 93.85 cm respectively, the stability coefficient of them were 99%. Combined with the agricultural demand, the errors were within the allowable range. The correctness of the optimized design, the feasibility of the solution and the stability of the machine operation are further verified. [ABSTRACT FROM AUTHOR]

Plastic film has been widely used to mulch soil in croplands, but its recycling rate is less than 60%. Since natural degradation of plastic film is slow, accumulative use of plastic films has resulted in soil structure degradation and environment deterioration. Recycling the film residuals is hence mandatory. Manual picking is labor intensity and inefficient, and mechanical recycling is thus called. Most machines available on market are unable to separate the film residuals from straw and large soil particles during pick-up process. To alleviate this problem, we designed and tested an machine equipped with an improved cleaning system. We optimized the working parameters of the system in attempts to improve the residual recovery efficiency. Analysis of the structure of the cleaning system, its working principle and conditions, as well as the factors affecting the machine operation revealed that the most important parameters were the advancing speed of the machine, the speed of the film-conveyer, position of the pick-up drum and the speed of the secondary impurity-conveyer. We investigated the recovery rate of the film residuals, rate of separating the film residuals from the straw, and transport efficiency of the impurity, using the regression orthogonal combination tests with four five-level factors. The response surface of the testing results was analyzed using the design-expert software, and the relationship between each impacting factor and the testing index was also analyzed. The results showed that the main and secondary factors affecting the picking-up rate were position of the picking drum and the advancing speed of the machine, and that the factor affecting the separation rate mostly was the speed of film transportation followed by rotating speed of the impurity conveyer. The transport efficiency was affected mostly by the rotational speed of the impurity conveyer, followed by location of the pick-up drum, speed of the film-conveyer and advancing speed of the machine. The regression model was optimized with multiple objectives, and the optimal working parameters for the cleaning system are: Advancing speed of the machine and equipment: 1.26 m/s, speed of the film transporter: 1.55 m/s, position of the pick-up drum: -17 mm (taking the center of the hole in the supporter and the center of the picking-drum in the vertical direction as the origin, adjusting 17 mm to the forward direction of the machine), speed of the secondary impurity conveyer: 205 r/min. Calculated using these optimal parameters, the pick-up rate of the film residuals was 90.19%, the separation rate of the film residuals from the impurities was 92.21%, the impurity transport efficiency was 89.6%. We verified these against field experiments, and the results showed that the picking-up rate was 91.54%, the separation rate was 90.37%, and impurity transport efficiency was 88.4%. This paper offers references to improving quality of the cleaning system in plastic-film pick-up machine. [ABSTRACT FROM AUTHOR]

This paper was aimed to reduce the vibration energy transitivity form the cutting table of the combine harvester to combine. In this paper, the 4 L-0.2 micro combine harvester was chosen as the object, the structure of the machine and the characteristics of the header were analyzed, and the minimum vibration amplitude point of the cutting table was found by using the minimum amplitude point method. Then the finite element modal analysis of the cutting table was carried out by using the modal analysis software Workbench, and the first four order modal frequencies and shapes were obtained, which were also acquired through the modal experiment of the cutting table. The experiment result was proved to be believable by comparison with the finite element modal analysis result. Three different experiments were performed, which included the preliminary experiment, the single-frequency excitation experiment and the verification experiment. In the preliminary experiment, the motor was used to provide the power which was used to drive the cutter installed on the cutting table to reciprocate; the preliminary experiment was done under the condition of low frequency, and 3 different frequencies, which had significant influence on the vibration amplitude of the points, were obtained, which were 5, 10 and 15 Hz respectively. The single- frequency experiments were done on the base of these 3 frequencies. In the single-frequency experiment, a small area that contained the positions of the first four order modal node of the experiment mode was divided out from the experimental area on the cutting table. Some points were randomly chosen in the small area, and the exciter was used to force the cutting table to vibrate. The values of vibration amplitude of the points chosen were obtained, and they were imported into the MATLAB together with the coordinate values of the points. The least square method was used to obtain the fitting curve, which illustrated the relationship between the coordinate value and the value of vibration amplitude of the points. The points that had the minimum value of vibration amplitude were found at each frequency. According to the vibration theory, it could be seen that the value of the vibration amplitude in the time domain was the superimposition of the value of amplitude of each frequency. The weighting factors corresponding to the 3 frequencies were obtained, which were 0.54, 0.3 and 0.16 respectively according to the relationship between the 3 different frequencies obtained from the preliminary experiment. The positions of the points that had the minimum vibration amplitude could be calculated with this set of weighting factors. In the verification experiment, the motor was used to provide the power for driving the cutter installed on the cutting table to reciprocate. The experimental data were calculated and the experimental result was consistent with that of the finite element analysis, and the positions of the points that had the minimum value of the vibration amplitude were obtained, which weighted average magnitude for the region (29.707 m/s2) 89.29%, the maximum amplitude point amplitude (35.044 m/s2) 74.92%. At the end, the optimization scheme which provided the best position for the installation of the cutting table was put forward according to the result. After changing the connection point, the cutting table's structure was analyzed, and the results showed that the structural strength of the cutting table met the requirements. [ABSTRACT FROM AUTHOR]

The rice-wheat cropping system is the main grain production model in many areas of China, especially in Jiangsu with the area of about 1.8×106 hm2. In other provinces of China along the Yangtze River valley, such as Sichuan, Anhui and Hubei, there are large areas of such cropping system. However, the rice straw processing before wheat planting has caused some problems in these places. As straw burning is forbidden by the government, straw incorporated to field is an available alternative method to process the rice straw. Traditionally, rice straw should be smashed and buried before wheat planting, which requires time and energy. Also, burying rice straw in soil will influence the growing of wheat if the seed stay on the straw. Furthermore, the soil nutrient will be consumed during straw decomposing. The clean area planting technology under full straw cropland, invented by Nanjing Research Institute for Agricultural Mechanization, Ministry of Agriculture and Rural Affairs, China, can complete seeding and straw mulching in the same time, which is a good method to deal with the straw processing problem. However, as the quantity of rice straw is relatively larger than any other straw, the excess rice straw mulching will impact the emergence of wheat, which is likely to cause low yield. To solve the problem, in this paper, we provided the rice straw processing model of part burying and part mulching based on the clean area planting technology under full straw cropland. Then, different straw distributed retention devices with different structures, including flat board with horizontal upward opening, oblique board with horizontal downward opening, flat board with several longitudinal openings and curved board with several longitudinal openings, were designed and introduced respectively. After the tests of these distributed retention devices under different parameters, the structure of curved board with several longitudinal openings was selected as the best one. On the basis of structural development, the central composite test method was used to optimize the key parameters of straw distributed retention device. The gross width of longitudinal opening, quantity of longitudinal opening and revolving speed of picking and smashing device were taken as the influencing factors. The variable coefficient of uniformity and deviation rate of distribution were taken as response values in the experimental study. Orthogonal rotational quadratic combination test with three factors and three levels was made to evaluate the combined influence of the factors on the test index value. Furthermore, regression equations to describe the relationships between the factors and each assessment index were established by using the regression analysis and response surface analysis with the software Design-Expert 8.0.6. The optimum combination of the selected parameters was obtained and verified, and the experimental verification of the mathematical model was also conducted. The results showed that trial factors had great effects on the performance of straw distributed retention device. The significant effects of quantity of longitudinal opening, gross width of longitudinal opening and revolving speed of picking and smashing device on reducing the variable coefficient of uniformity were in a decreasing order. The significant effects of gross width of longitudinal opening, quantity of longitudinal opening and revolving speed of picking and smashing device on reducing the deviation rate of distribution were in a decreasing order. The best parameters of the integrated straw distributed retention were as follows: when the gross width of longitudinal opening was 600mm, the quantity of longitudinal opening was 7 and the revolving speed of picking and smashing device was 1900r/min, the variable coefficient of uniformity and deviation rate of distribution were 18.75% and 0 respectively. The model validation tests were repeated for 3 times on the simulation field by using the optimization results, the values of practical variable coefficient of uniformity and deviation rate of distribution were 19.68% and 0 respectively. The percentage points of absolute error between the experimental and predicted values of variable coefficient of uniformity and deviation rate of distribution were 0.93 percentage point and 0.33 percentage point respectively, which indicated a reasonable choice of optimization conditions. The research results can provide references of technology and equipment for wheat planting after the harvest of rice in rice-wheat cropping system area in China. [ABSTRACT FROM AUTHOR]

Astragalus smicus, also known as Chinese milk vetch, Zi yunying and so on, is one of the main winter green manure crops in paddy fields of central and southern China, it has the advantages of reducing fertilizer input, improving soil fertility, increasing crop yield and quality, and protecting ecological environment, and has strong nitrogen fixation ability and high utilization efficiency. In recent years, the production machinery of Astragalus smicus has been developed and applied rapidly in terms of capacity and utilization efficiency, but its development still lags behind. Ditching and sowing are important links in the production of Astragalus smicus. The yield of Astragalus smicus is largely determined by the quality of sowing, and ditching operation can make Astragalus smicus grow well in low-humid field with poor drainage or sandy soil with poor fertilizer and water retention. Astragalus smicus is often used as green manure in paddy field, but high stubble retention, large amount of straw, insufficient in sowing height of existing other sowing equipments, working parts easily clogged, etc., bring difficulties for mechanized production of Astragalus smicus. In order to solve the influence of machine-harvested rice stubble on mechanized production of Astragalus smicus, aiming at the problems of low quality and low production efficiency in independent ditching and sowing links at present, a Astragalus smicus ditching and sowing machine which suitable for machine-harvested rice stubble field was developed. A height adjustable sowing device was designed, by which the sowing components could be lifted to a proper position according to the residual straw situation in the field. The special seed-metering wheel and quantitative evenly-sowed device for Astragalus smicus were developed to achieve precision sowing and improve the sowing uniformity. The structure and working parameters of the double-disk ditching components were determined. The variation coefficients of ditching width and depth determined by field experiments were less than 6%, which met the drainage requirements of Astragalus smicus growth process. The multiple factor experiments and regression analysis of the test data were carried out by Design-expert software, the results showed that forward speed of machine, rotation speed of seed-metering wheel, seed-uniforming cylinder diameter significantly affected the sowing performance, the results of variance analysis showed that the rotation speed of seed-metering wheel had the greatest influence on the emergence rate and coefficient of variation of sowing uniformity, while the forward speed of machine had the least influence on the emergence rate and coefficient of variation of seed-metering quantity consistency, regarding the coefficient of variation of sowing uniformity, the most influential factor was seed-uniforming cylinder diameter, and the minimum impact factor was the rotation speed of seed-metering wheel, the optimal factor parameters combination which affected the sowing quality of Astragalus smicus ditching and sowing machine was as follows: forward speed of machine was 4.6 km/h, rotation speed of seed-metering wheel was 44 r/min, seed-uniforming cylinder diameter was 6 mm. Verified by field experiments, the Astragalus smicus emergence rate was 95.87%, quantity consistency was 12.7%, coefficient of variation of sowing uniformity was 8.07% in the condition of optimal parameter combination, the relative error was below 3% compared with optimal values predicted by the model. Compared with the existing sowing methods of Astragalus smicus, working efficiency of the designed ditching and sowing machine was 1 hm2/h, which was superior to the artificial sowding working efficiency of 0.1 to 0.125 hm2/h, the hand-shaking working efficiency of 0.2 to 0.3 hm2/h and the motorized sowing working efficiency of 0.5 to 0. 8 hm2/h, and was lower than the UAV sowing working efficiency of 3 to 4 hm2/h. In addition, the coefficient of variation of sowing uniformity and the combination type of ditching and sowing machine were also significantly superior to that of other methods. The Astragalus smicus ditching and sowing machine developed in the paper integrated ditching and sowing links in one operation, the working efficiency was greatly improved, the research provided a new method for Astragalus smicus ditching and sowing machine for machine-harvested rice stubble field. [ABSTRACT FROM AUTHOR]

The perpendicularity is an important index for evaluating the quality of pot seedling transplanting. At present, the planting mechanism easily resulted in lower tilt and lower perpendicularity of seedling, which leads to lower survival rate of the seedling in the bowl. In order to solve this problem, according to the agronomic requirements of pot seedling planting and based on the physical characteristics of pot seedling, the design requirements of planting mechanism were put forward in this paper, and a planetary gear-train slid way planting mechanism was designed. Through the cooperation of the planetary gear train and the slide track, the pot seedling planting in the bowl was accomplished by the way of shooting seeding, and the operation process of the mechanism was analyzed, and the kinematics model of the mechanism was established. Based on MATLAB, the optimization software of auxiliary analysis of planting mechanism was compiled, and the planting track and structural parameters of the mechanism were optimized, and a group of optimal structural parameters that meet the requirements of seedling planting was obtained, that means, the radius of solar wheel R0= 20 mm, the radius of middle wheel R1= 15 mm, the radius of planetary wheel R2=10 mm, the length of connecting rod(BC) L1= 100 mm, the length of rod CD on planting arm L2= 150 mm, the length of rod CF on planting arm L3= 80 mm, the length of duck bill planter(FG) L4= 140 mm, the distance from point E to origin of coordinate O on a slide DE L5= 100 mm, the angle of initial installation of planetary frame(OB) α0= 45°, the angle between connecting rod BC and X axis α1= 45°, the angle between rod DC and rod CF of planting arm β=176°, and the angle between slide DE and X axis θ=108°. In this combination, the structure design and 3D virtual assembly of the planting mechanism were completed, and the virtual movement and simulation analysis of the mechanism were carried out in ADAMS, and the rationality and accuracy of the mechanism design were verified. According to the optimized parameters, the physical prototype was produced, and the field experiment was carried out with the vertical degree of the bowl seedling as the main test index. The field test results showed that when the speed of the planter was 450 mm per second and the planting frequency was 74 plants per minute, the transplanting perpendicularity was high, and the qualified rate was 94%, which meets the requirements of planting performance. The results can provide references for designingplanting mechanism of potted seedling transplanting machine. [ABSTRACT FROM AUTHOR]

In recent years, with the rapid development of agricultural mechanization in China, rice transplanter has been widely used. Because the transplanting parts of the transplanter have a large vibration in the working process, it will have a great impact on the operation of the machine and the operating environment of the driver. At present, the analysis of the vibration of the support arm of the transplanter and the research on how to reduce the vibration and noise are still in initial stage. In the working process, the support arm bears a variety of dynamic loads, including the working load of various parts, engine and road surface stimulation. When the frequency of the dynamic load is close to the natural frequency of the support arm, the resonance phenomenon will occur. The mechanical resonance affects the normal operation of the transplanter, reduces the service life of the transplater, and seriously affects the comfort of the working environment. Therefore, it is of great of significance to study the vibration and noise reduction of rice transplanter. In view of the vibration and noise problems in the power transmission process of high-speed rice transplanter planting mechanism, 2ZG-6DK rice transplanter was taken as the research object in this paper, and the power transmission mode and working principle of planting system were analyzed. The 3D software was used to standardize the support arm which is the key components in the power transmission system of the transplanter, and the model was imported into the ANSYS Workbench and combined with the Lanczos Method to solve the modal natural frequency and mode shape. In order to optimize the structure of the support arm based on the finite element model, it is necessary to verify the accuracy of the finite element model of the support arm. The modal test of the supporting arm of Nantong 2ZG-6DK transplanter was carried out by using DH5902 Dynamic Data acquisition and modal analysis system, the first 4-order modal frequency and mode of the support arm of the transplanter were obtained by signal analysis and parameter identification. The accuracy of the finite element model of the support arm was verified by the comparison between the modal test results and the finite element analysis results. Based on this, MAC-based (modal assurance) was carried out and the accuracy of finite element analysis was verified. The criterion test optimized the modal test to verify the accuracy of the finite element theory analysis. In order to avoid the external excitation frequency of the support arm, based on the analysis of the external frequency excitation characteristics, and on account of the ISIGHT multidisciplinary software platform, the structural parameters of the support arm were optimized by the sequential quadratic programming method. The results showed that the thickness of the optimized support arm sidewall cavity was 5.7 mm, the beam width was 42.0 mm, the arm length was 497.0 mm, and the first 4–order modal frequencies were adjusted to 135.17, 204.23, 483.14 and 702.32 Hz respectively, which all avoided the gasser engine excitation frequency range 86.67~120 Hz. After the optimization, the vibration amplitude attenuation was the most obvious at the 1-order frequency, the vibration amplitude was decreased by 9.4%, and the low-frequency vibration characteristics of the support arm were significantly improved. The research results can provide reference for the vibration characteristics analysis and vibration reduction design of the rice transplanter. [ABSTRACT FROM AUTHOR]

It is theoretical basis for harvest machinery selection to discuss technology productivity changing with plot conditions, which are plot area, length, width and so on under the condition of land managing scales over the wide range. Harvesting operation is one of the key processes of grain production, and choosing the appropriate harvesting machine is a vital step to reap the grain with larger technology productivity. A lot of researches on agricultural mechanization selection have been done by both domestic and foreign experts. It has been found that there are existing methods for agricultural machine selection such as fuzzy clustering comprehensive evaluation method, linear programming, and mixed integer linear programming. In these methods, the economic performance of the agricultural machinery unit is the objective considered in most cases. But the technical performances of agricultural machinery units, such as the practical productivity, are usually neglected. Plot conditions, including plot area, length, width, and distance between plots, are not considered in the methods, but they are important factors influencing the technology productivity of agricultural machineries. At the same time, it has also been found that the power of most agricultural machineries does not match the plot conditions in the practice of agricultural production. In this paper, the mathematic models calculating every kind of time consumption item during combined operation, including working time, turning time, preparation time before unloading, unloading time, preparation time after unloading and transferring time between plots, were established. On the basis of that, the mathematic models for calculating the combines’ technology productivity under the condition of different unloading ways were also set up. These mathematic models contain the variables such as plot area, length, width and distance between plots, and reveal the regularities of technology productivities changing with plot conditions. Experiment was designed according to the method of tracing the practical operating process. Taking 8 kinds of typical combines for harvesting soybean as experiment objectives, the values of all kinds of time consumption items were tested under the condition of fixed distance during the process of normal harvesting operation after enough experiments were executed. All the data of time consumption items were checked using the normal distribution models and the error data were removed according to the 3-Sigma principle. The mathematic models of time consumption items and combine technology productivity established were proved to be correct by the experiments and the actual operating status. According to the models and tested data, the technology productivities of 8 kinds of combine harvesters changing with plot conditions were calculated after the MATLAB program was designed and executed. Curve groups of technology productivity of each kind of combine changing with plot conditions were drew out using the EXCEL. Thus, the quantitative regularity of technology productivity of combine changing with plot conditions was revealed. According to the regularity, the technology productivity became larger as the value of plot area and length became bigger, but the changing velocity of technology productivity became slow after a specific values of plot area and length. The technology productivity of combine with the header width of 2-3 m was higher when the plot area was more than 3 hm2 and the length was more than 400 m. For the combines with the header width of 4-5 m, the technology productivity was higher when the plot area was more than 5 hm2 and the length was more than 600 m. The technology productivity of combine with the header width more than 7 m was higher when the plot area was more than 7 hm2 and the length was more than 800 m. The results of the paper can provide the direct theoretical guidance for practical combine selection under the status of land managing scale with large range, and they are also the improvement and supplement for the theory of agricultural machinery selection. [ABSTRACT FROM AUTHOR]

In China, Camellia oleifera fruit is deeply loved by consumers as specific woody oil resource. Because of the composition of fatty acid for camellia seed oil is highly similar to olive oil, it is also known as “Oriental olive oil”. However, the shelling operation of Camellia oleifera fruit largely relies on natural drying, which is of low efficiency, high labor intensity, high processing cost, and great dependence on weather. In order to improve the performance of shelling machine for Camellia oleifera fruit, increase the shelling rate and reduce the seed breaking rate, choosing the shelling rate and seed breaking rate as the indices, 3 aspects were studied based on the existing shelling equipment and practical engineering experience in this paper. Firstly, the physical parameters of Camellia oleifera fruit were studied. The parameters such as density, bulk density, grain size, water content and proportion of each component of Camellia oleifera fruit from Changning City were measured, which provided the data for the design of shelling machine parts. Secondly, the mechanism and main structure of the shelling machine were studied. In the beginning, the merits and defects of commonly-used methods for shelling were summed based on their working principle and mechanism. According to practical engineering experience and the measured data above, the final squeeze-rub shelling method for Camellia oleifera fruit was determined. Then the structure of main parts was designed, which included the shelling device consisting of the roller, annular plate and the regulating mechanism, and the separation device consisting of stirring shaft and circular groove structure screen. Finally, the three-dimensional (3D) prototype model was established and the drawing design was completed. Thirdly, the operating parameters of shelling machine for Camellia oleifera fruit were studied. The shelling machine for Camellia oleifera fruit was manufactured based on the structure design, and then the operating parameters’ optimization test was made. In the experiment, Camellia oleifera fruit’s shelling gap, speed of shelling motor, speed of separation motor were taken as single factors, respectively, and the shelling rate and seed breaking rate were taken as indices. The influence trend of these factors on the indices was drew out. Based on the result, the orthogonal experiment was designed, which aimed at studying the effects of the speed of shelling motor, the speed of separation motor and the gap of shelling on shelling rate and seed breaking rate. The results indicated that the water contents of the fresh Camellia oleifera fruit, shell and seed were 60.08%, 74.55% and 45.60%, respectively. The particle size distribution was 20-50 mm, and the bulk density was 0.52 kg/L. The optimal combination parameters were that the speed of shelling motor was 125 r/min, the speed of separation motor was 343 r/min and the shelling gap was 12 mm. And under the condition, the shelling rate was 96.91%, the seed breaking rate was 3.38% and the production capacity was up to 2 t/h. The optimal parameters achieved in this paper can provide reference and technical support for the actual application of shelling machine for Camellia oleifera fruit. And it will benefit the processing industry of Camellia oleifera fruit. [ABSTRACT FROM AUTHOR]

The application of mechanical transplanting on crops can effectively increase the product of crops and reduce the labor intense as modern cultivation techniques. But the popularization and application are limited by the problem of lower upright degree to some certain extent. A new type cam-swing link type transplanting machine was designed to solve the problem of lower upright degree in current pot seedling planting machine. In addition, the receiving seedling stability of planting apparatus can be guaranteed well, owing to double parallel four-bar mechanism of this planting machine. In this paper, the kinematic model of the transplanting machine was established, including the equations of planting trajectory, planting velocity and planting acceleration for the planting device. For the purpose of high efficiency, interactive GUI design tool had been explored based on the MATLAB/GUI according to these mathematic equations. The influences on the transplanting trajectory of main parameters were analyzed based on MATLAB tool, including the length L1 and original phase angle Φ1 of crank CD, the length L2 and original phase angle Φ2 of swing AB, and the length L5 of link AG. The system parameters which had great effects on the planting trajectory were L1, L2, Φ1 and Φ2. These parameters were analyzed and optimized through the method of orthogonal experiment. The experimental scheme was designed according to orthogonal table off our factors and three levels. By analyzing the range table of residual, the parameter could be ranged as L2, L1, Φ1 and Φ2 from big to small, considering the degree of significant on upright degree of seedlings. The optimal combination could be selected that L1 is 118 mm, L2 is 52 mm, Φ1 is 256°, and Φ2 is 316°. Under the condition of this optimal combination, the motion model of transplanting machine was reestablished to generate a new optimized planting trajectory. The top of this trajectory was smooth to benefit the receiving seedling stability of planting device. As the total height of this trajectory was about 256 mm with 190 mm higher the ridge side, the planting device could avoid touching down seedlings planted effectively. When the planting depth reached 60 mm, the maximum residual of curve at planting seedlings parts was 0.465 mm, the mean residual was 0.253 mm, and penetration angel was 81.05°. The simulation results indicated that this optimized planting trajectory can improved the anteversion problem of seedlings that caused by compaction wheel and ensured the seedling planted higher upright degree. In order to verify the reasonability and accuracy of the theoretical model, the prototype was processed with the optimized parameters. Based on the prototype, field tests were carried out according to relevant standards in Yiyang county industrial park of China in March 2015. No crops were planted and the ridge film was mulched in the test plot before the testing, for simply obtaining test results without effects of the other crops. During the course of experiment, 30 horse-power tractor was selected as the only power. The total height of seedlings used was no more than 150 mm, and the height of seedlings substrate less than 60 mm. The plant vertical degree was considered as the main optimization indicator which influenced by the main parameters mentioned above. The data results showed that the mechanism proposed meet the requirements of pot seedling agricultural plant at the speed of 0.556 meter per second, and planting frequency was 60.7 plant percent minute. The qualified rate of upright degree with the variation coefficient of 2.03% was 95%, lodging rate was no more than 1.67%, and plant spacing error rate was only 0.22% with no lacking of seedlings. The results indicated that this machine had the good planting performances of high upright degree and low spacing error rate under the condition of high efficiency of planting. What this paper studied will provide theoretical reference for the subsequent transplanter research and development. [ABSTRACT FROM AUTHOR]

The seed-metering link plays an important role in the process of plot sowing, and mechanized seed metering can reduce the labor intensity, improve the production efficiency and ensure the work quality. The seed-breeding seed-metering technology has been vigorously developed in China. However, at present, there are many disadvantages in the existing seed-breeding seed-metering device. In order to make plot sowing seed-metering device meet the requirements of high level test in plot sowing, this paper designed a cone canvas belt type metering device which applied a new type of structural material, analyzed the characteristics of the structure, and furthermore, optimized the parameters by means of composite test. This seed-metering device could avoid the serious defects that the cone grid plate type seed-metering device has, i.e. uneven seeding and seed injury. The mechanism consisted of a seed hopper, a seed-dispersing hand shank, a canvas belt type metering mechanism, a lever mechanism of adjusting tension, a base plate of seeding device, a receiving funnel and a spiral bevel gear. The structure parameters of the cone grid plate type metering device were not easy to distinguish and appraise. Some of them directly affected the performance of seed-metering device. Before further studying the parameter, the working process was divided into 3 links, which were discharging seeds, dispersing seeds and carrying seeds. By analyzing the seed mechanics, the seed kinematics and the conditions of space configuration about discharging seeds, dispersing seeds and carrying seeds, this paper found that a number of parameters had significant impact on the operation performance of the machine, and at the same time there was internal relationship between these parameters. Aiming at comparatively evaluating these parameters, this paper conducted the single factor experiment on discharging seeds. Through the above methods, the main parameters which influenced the performances of seed metering were identified: cone rotational speed, cone angle, and unit configuration amount in wedge-shaped ring domain. Through three-factor quadratic orthogonal rotation design, the regression equation of factors and test index (coefficient of variation of seed-metering uniformity) was established; the optimization of calculation showed that when the cone speed was 3.46 rad/s, the body bottom angle was 45.8°, and the unit configuration amount in wedge-shaped ring domain was 7 grains per centimeter, the comprehensive performance evaluation index reached the best level in the breeding test. Implementing the reproducibility test showed that the result of parameter optimization was accurate. The seed-metering technology was applied by 2BZH-6 type wheat nursery seeder for planting operation in different plot area. Under the condition of wheat seedling emergence, the statistical results were obtained by measuring the distance of the wheat plants: the average plant spacing was 51 cm for the cone grid plate type seed-metering device; and the coefficient of variation of uniformity distribution was 27.43%, which was relatively low. In addition, there was no phenomenon of residual seeds or broken seeds. The research results provide the reference for improving the design of the existing wheat nursery seeder’s seed-metering component. [ABSTRACT FROM AUTHOR]

The low level of Chinese corn harvest seriously has restricted the corn harvest mechanization. Modal analysis is a very important and useful method for various engineering applications, such as design and dynamic test. There are few researches on vibration test and modal analysis of corn combine harvester frame, which is a key part of the corn harvester. During the harvester’s operation, the frame carries and supports the assembly and components, such as engine, cutting header, cab, picking mechanism, elevator, granary, tank, and all alternating loads will eventually pass to the frame. When the vibration frequency is caused by the external excitation and closed to the natural frequency of the frame, it will produce resonance phenomenon, which accelerates the frame strength failure, and therefore affects the dynamic performance and reliability of the frame structure. Using the method of combining the vibration test and modal analysis, this paper studies the vibration characteristics and optimizes the frame, which has the guiding significance for the corn combine harvester design and optimization. Firstly, the paper studies the finite element modeling and analysis method of the frame, and obtains the natural frequency and vibration mode based on the theory of modal analysis. Secondly, using the method of time domain and power spectrum analysis, the paper analyzes the field road test data, and gets amplitude characteristics and power spectrum at 4 measuring points of the frame, as well as attains the excitation frequency of road roughness which is concentrated in the range from 0 to 2.4 Hz, and the whole machine key components’ excitation frequency, and studies the influence of the frame. Eventually, this paper studies the influence of discontinuous change of the interval of frame wall thickness and stiffness on the frequency and mode, improves the first-order frequency based on the fundamental frequency optimization method, and then puts forward the improvement scheme and optimized frame structure. The result shows that the vibration frequency of the rear bridge above the frame is 9.79 Hz, close to first-order resonance frequency, which has caused resonance and strength failure. At the same time, the vibration amplitude of the frame from high to low is as follows: the rear bridge above the frame, the engine beam position, the engine longitudinal beam position, and the front bridge above the frame. The vibration amplitude of the rear bridge above the frame exceeds the engine amplitude, which illustrates the resonance has occurred. After the optimization, the first-order natural frequency of frame keeps away from the external excitation, which increases from 15.9927 to 22.4595 Hz, and at the same time, after the optimization of vibration shape, the first-order torsional eigen mode magnitude decreases from 7.778 to 3.768; the first-order bending eigen mode magnitude decreases from 6.83 to 3.651, which has improved the mode shape. The durability test shows that the failure rate of optimized frame is reduced, and the mean time without failure increases from 20 to 60 h. This paper presents the modeling analysis, vibration test, data processing and structure optimization method, and provides a good reference for corn combine harvester vibration control and performance optimization. [ABSTRACT FROM AUTHOR]

Today, ridge tillage method is an effective farming method that can resist the drought and flood in the northeast area of China. Because of the climate and natural conditions, most of the northeast area of China will continue to adopt ridge tillage method. In the case of ridge planting, no-till can improve the ground temperature, and can control the summer flood and drainage. In recent years the strip rotary tillage type no tillage planter has been extended. Because of the rotary tillage, the root stubble is broken and the anti-blocking performance is good. However, the soil tillage intensity is between 6.5 and 7.8, and the tillage destroys the original ridge, and forms the new ditch. At present, the number of no tillage finger clip type precision seeding and fertilizing machine applied in the production, is about 3000 in the northeast area of China, and the soil tillage intensity index is 1, which reduces the soil tillage intensity and produces no new ditch; but the two-row machine has the complete machine weight of 1000 kg, which brings too large compaction on soil, and makes ridge stand almost flat, therefore, wheel rut compaction seriously affects maize root growth. This machine not only loses the advantage of ridge planting, increases soil hardness, but also enhances manufacturing cost, and makes the price per machine high. The cost of the field operation is greatly improved, which does not accord with the requirements of energy saving and emission reduction in agricultural production. For no tillage planter, the current problem is the existence of the problem remains a ridge shape. Aiming at the requirement of researching and developing new no tillage planter for the conservation tillage corn ridge agricultural technology in the northeast area in China, based on the Archimedes spiral theory, this paper analyzes the notched disc knife break crop performance and the technical requirements to stubble breaking cutter for ideal seed bed, optimizes the spiral notched disk break stubble cutter structure and carries out the optimal selection of parameter; and develops the stubble breaking ditching device and stubble breaking anti-blocking device. Through test verification of stubble breaking ditching device, it opens a "V"-shape groove, and 2 pieces of spiral-notch disc cutters have a diameter of 350 mm, when sowing depth is 40 mm, sowing and ditching width is 28 mm. Increasing the weight makes the stubble breaking ditching device achieve a weight of 100 kg, and in the area implementing high stubble conservation tillage mode and with a field coverage rate of 30%, stubble breaking ditching device can be adopted instead of the conventional planter seeding furrow opener, and ordinary seeder can realize no tillage planting. When stubble breaking anti-blocking device’s breaking stubble depth is between 70 and 100 mm, ditching width is 40-50 mm, and ridge cleaning width of ridge cleaning parts is 210 mm, which are up to the requirement of agricultural technology. Increasing the weight makes the monolithic disc broken stubble device achieve a weight of 113 kg in the area implementing conservation tillage of high stubble breaking rod cover mode and with covering rate of 1 kg/m2, stubble breaking anti-blocking device can be adopted, and ordinary seeder can realize no tillage planting. In this paper, the development of the rolling disc coulter and its edge is Archimedes spiral gap, after test for many times, stubble cutting resistance is small, the weight of machines can be reduced, because it is a passive anti-blocking device, keeping the shape of ridge. [ABSTRACT FROM AUTHOR]

Yellow silage corn stover is taken as a kind of important feedstuff for animal husbandry. Corn stover pickup balers are used to collect the stover and bundle it into straw bale in the harvest process of yellow silage corn stover. But in Northeast China, the soil has strong adhesiveness when it is in high moisture content. And when the moisture content is low, the soil disperses into fine particles which are easily carried in the miscellaneous branches of stover. It is a fleeting moment when stover is gathered and transported into baler. Soil adhered to stover and carried by the branches can’t be removed in this short process. As a result, high soil content reduces feed quality of yellow silage corn stover. In order to solve the problem of high soil content of yellow silage corn stover, the paper proposed to remove the soil adhered and included in stover by means of vibration. The soil removal mechanism of stover pickup baler by vibration was fitted on the bottom of the machine. It is connected between the pickup unit and the cutting and rubbing unit. Stover can be picked up and delivered to the vibrating conveying screen to remove the soil. Then, the stover would be robbed, cut and bundled. The operating principle of the test-bed was clarified through the design of the test-bed and analysis of high-speed camera. Collision between stover and screen and internal friction of stover could release soil in the stover. Stover thickness, vibration time, vibration amplitude and vibration frequency were 4 influencing factors acting on performance of soil removal in the tests. Taking the soil removal rate and the stover loss rate as indices, single factor experiments were conducted to determine the value range of each parameter on the whole-plant stover (long stover) and chopped stover (short stover) on the ground respectively. The result showed that the soil removal rate and the stover loss rate increased with the increase of vibration time, vibration amplitude, and vibration frequency. But the soil removal rate and the stover loss rate dropped with the increase of stover thickness. It was given that the focus ranges of values of all parameters were vibration time from 10 to 14 s, vibration amplitude from 10 to 20 mm, vibration frequency from 4 to 6 Hz for long stover, and vibration time from 12 to 16 s, vibration amplitude from 10 to 20 mm, vibration frequency from 4 to 6 Hz for short stover. Through the three-factor orthogonal polynomial regression test, the author found the change laws of the soil removal rate and the stover loss rate determined by vibration frequency, vibration amplitude and vibration time. Four regression equations were induced according to experiment and analysis above. Then, a comprehensive index indicating soil removal rate and stover loss rate toward the optimum synchronously was made to evaluate the effect of soil removal. By analyzing the regression equations and the comprehensive index, an optimal solution was obtained. The optimal combination of soil removal from corn stover by vibration was as follows: For the long stover, the vibration amplitude was 15 mm, the vibration frequency was 4.5 Hz, and the vibration time was 14 s; for the short stover, the vibration amplitude was 20 mm, the vibration frequency was 4 Hz, and the vibration time was 12 s. Verification tests were conducted on the test-bed to verify the results above. Through calculating with the regression equations, the soil removal rate and the stover loss rate of long stover were 4.71% and 0.34%, respectively, and for short stover, the calculating results were 4.44% and 1.42% respectively. In the verification tests, the results were 4.80% and 0.38% for long stover and 4.72% and 1.53% for short stover. By comparing the simulated and the experimental result, it was found that the relative errors of the soil removal rate and the stover loss rate were acceptable. It was believed that the result of mathematical model matched the test result well. This study provides references not only for removing soil from stover by vibration, but also for the improvement of corn stover pickup baler design. [ABSTRACT FROM AUTHOR]

At present, in the trellis vineyard, the methods of mechanical weeding are mainly divided into inter-row mechanical weeding and intra-row mechanical weeding. The development of intra-row mechanical weeding is relatively slow, because the identification and location for crop and weed is difficult in the process of mechanical weeding. Now, the theoretical study on intra-row mechanical weeding of trellis cultivated grape is not very much. In order to achieve the intra-row weeding of trellis cultivated grape, this paper designs an auto obstacle avoidance mechanism based on the existing weeder, which includes parallel four-bar linkage mechanism and trigger mechanism of obstacle avoidance. The contact rod is composed by 2 straight lines and an arc connecting straight lines in the trigger mechanism of obstacle avoidance. And the theoretical working principle of auto obstacle avoidance mechanism is described. After the pre-test, it is found that the length of the straight section of the first section of the rod, the arc angle of the intermediate transition arc and the 3 distances between the contact rod and the edge of the weeding part have obvious effect on the result of weeding. So a virtual prototype model for auto obstacle avoidance mechanism is built in ADAMS, and the trigger mechanism of obstacle avoidance is parameterized. Then, the orthogonal test is conducted by taking the combination of 3 distances between contact rod and edge of weeding part and the length of the first part of the rod as the test factors and the area which is not covered by the weeding parts after the work as the experimental index. The results show that the combination of 3 distances and its interaction with the arc angle of intermediate transition are significant factors. In order to analyze the effect of the combination of 3 distances on the area not covered by the weeding parts after the work deeply, the length of the first part of the rod is set as 1050 mm, the arc angle of intermediate transition is 85°the forward speed is 390 mm/s, the initial velocity of the cylinder is 50 mm/s, and furtherly taking the parameter the combination of 3 distances as the test factor and the area not covered by weeding parts after the work as the experimental index, the optimization simulation is conducted. The results show that the optimal value is obtained when the 3 distances between contact rod and edge of weeding part are 225, 300, and 212 mm, respectively. The area not covered is 783 mm2except the scheduled area which is not needed to weed. It is very small, so the weeds can be considered to be removed completely, which shows the result of weeding is good. On the basis of simulation optimization, the field tests of single obstacle avoidance and continuous obstacle avoidance are also carried out, in which the combination of 3 structural parameters of the obstacle avoidance mechanism is set as variable and the parameters such as length of the first part of the rod and arc angle of the intermediate transition arc as constant values. The field test results show that the average coverage rate of weeding operation after optimization is 97.5%, which is about 8% higher than before, and the standard deviation is 2.98%, which is lower than before. The stability of weeding is also better, and the effect of optimization is obvious. Generally, this study enriches the method of identification and location for crops and weeds in the process of mechanical weeding, and also provides reference for the improvement of the design of intra-row weeder for trellis cultivated grape. [ABSTRACT FROM AUTHOR]

The seed potato distribution is not uniform, and the seeding quality and quality of back fill is poor when potato seed casting into the furrow by using the ditching shoe and disc opener. In this study, the splitter sliding-knife potato opener was designed and optimized. It had a good embedded performance. The opener was towed by a tractor when the potato planter was operation. The installation site was under the seed-metering device and the longitudinal direction of opener can be adjusted to requirements. A V-shape furrow was got after the working process of opener. The soil particles were cutting and crashed by the edge of the shovel at the front side of the opener, and moved along the side surface of opener. Some of soil particles were fall into the furrow firstly to create a soft furrow thus providing a better furrow situation for potato to grow. In this paper, we also obtained the main factors that influenced soil covering for seed potato, by analysis of the soil particles in the process of motion on the side of the opener and the process of soil fall into furrow, and also kinematics analysis the seed potato falls into the furrow. The time at which the soil particles contact the bottom of the furrow was less than the time at which the soil particles fall into the furrow at the range of the resting angle. The planting effects were not only influenced by the parameters of opener, but also had a connection with the position of potato casted into furrow. The ideal seeding condition is that the potato fall into the bottom of the V-shape furrow, the lateral deviation coefficient of the seed potato is well, and the sowing quality is higher. To get good effects of planting, the time of potato fall into furrow should be less than that of soil particles fall back into furrow. The factors influencing the effect of the potato seed in the ditch were obtained through theoretical analysis after the movement parameters of planter were collected, and they were forward speed, depth of furrow, the length of opener and side angle of opener when initial conditions of the seeding were determined. A rotating orthogonal field experiment was designed. With forward speed, side angle of opener, length of opener and depth of furrow were taken as the experiment factors, coefficient of variation of row spacing, sowing width mean absolute deviation and quality of back fill as the test indices. The test was implemented in Heilongjiang Academy of Agricultural Sciences in June, 2015. The results showed the primary and secondary order of influencing factors for each test index. For the coefficient of variation of row spacing, the order was the depth of furrow, forward speed, the length of opener and side angle of opener. For the sowing width mean absolute deviation, the order was the depth of furrow, forward speed, side angle of opener and length of opener. For the quality of fill back, the order was the depth of furrow, forward speed, the length of opener and side angle of opener. The best structure parameter of splitter sliding-opener was obtained through field test. And results showed that the coefficient of variation of row spacing was 10.8%, sowing width mean absolute deviation was 3.83 mm, the quality of fill back was 24.1%, when the forward speed was 0.95 m/s, the opener of the side angle was 60 degree, the opener length was 500 mm, the depth of furrow was 115 mm. The comparison test showed that the V-furrow out of slide-knife opener was better than the ditch out of the traditional shoe-type opener. The reason was that the V-furrow can reduce seed movement and lateral displacement, to improve the consistency of the seed space. Besides, when the combination of the length of slide-knife opener was 500 mm and the side angle of the opener was 60°, the machine can provide enough time for potato seed into furrow, and the quality of fill back was also large so that potato seed can have enough soil cover and have a good ambient temperature and humidity for its growth. The sowing quality for the splitter sliding-opener was better than traditional opener. The opener designed was meeting the requirements of potato planting. The study of potato furrowing seeding device provided with reference to the design of a new theoretical support. [ABSTRACT FROM AUTHOR]

A new grooved-roller seed metering device is developed to overcome the breakage of seedling, obtain high sowing rate and raise seeding efficiency in present, and exercise the optimal design. Firstly, this paper introduces the main structure, the working principle and the related structural parameters of the device in detail. Seed metering device is a key component to realize mechanized cultivation of Pennisetum, which is divided into 2 types according to its working principle. One type is real-time cutting seed metering device and the other type is pre-cut seed metering device. Compared with real-time cutting metering device, pre-cut seed metering device has the advantages of high automation, no damage to seed and lower labor intensity, so it shows a good market prospect and is the main trend of the future development of the metering device. The grooved-roller seed metering device is one of pre-cut seed metering devices. In terms of the stem stress state of seeding process, the evaluation function of seeding smoothness with force angle of the stem as the target was derived. According to the function, opening width of the seed groove and depth of the seed groove were the main impact factors of the improved device’s seeding performance. Based on the compressive strength of the stem, the best size of seeding slot was deduced as 20 mm × 20 mm finally. The different morphology and difference of seed diameters are the main influence factors of the problem, and those are easy to cause the bud break. The smoothness and accuracy of seeding were improved by adding the elastic dunnages on the groove of the seeding drum. According to the evaluation function of seeding smoothness, the structure size of the dunnages was optimized as the side gasket thickness of 4 mm and the bottom gasket thickness of 8 mm. In order to study the effect of dunnages on the fluency, the model of grooved-roller seed metering device of the Pennisetum was established by using the dynamic simulation software ADAMS (automatic dynamic analysis of mechanical systems). The effect regularities of structural parameters and motion parameters on seed groove and dunnages were studied. The simulations showed that the new seed metering device could realize the orderly discharge of seeds, and obviously reduce the stress of small-diameter seed by using the plastic dunnages, ensuring the seed row stability and the adaptability of seed diameter. Then the real tests in the laboratory and field were undertaken to verify the conclusions of virtual tests. Bench test results showed that the gasket could improve the flow degree of the seed row to a certain extent, in which the roller speed fluctuation ratio was less than 10%, the roller torque fluctuation ratio was less than 400%, and the seeding rhythm fluctuation ratio was about 20%. The research further indicated that the quality of the seeding was not affected by the roller speed, and sometimes the faster speed would slightly improve the fluidity of the seeding. Because when the roller speed was faster, the time the stem entered the entry took shorter, which reduced the resistance of the seed row to a certain extent. The results indicated that the seed metering device can realize the seeding operation and the dunnages can effectively improve the seeding fluency. Field experiment indicated that the seeder was stable, and the qualified index was greater than 93.33%, the missing index was less than 4.1%, the multiple index was less than 2.5%, and the variance coefficient was13.63%. The indicators were in line with the planting requirements of giant grass. The research provides a theoretical reference for the design of grooved-roller seed metering device of Pennisetum and the technical reference for the related design of planting machine. [ABSTRACT FROM AUTHOR]

Sweet potato is an important food crop and can also be used as raw material for foodstuffs, animal feed and raw materials for renewable energy. Furthermore, research shows that it has anti-cancer effects. As sweet potato vines are long and difficult to be separated. The vines cleaned up before sweet potatoes harvest has a great role in promoting to improve the quality of sweet potato and the sweet potato harvest efficiency. In order to alleviate the shortage of sweet potato vines crushing machine in the hilly areas of China, the walking sweet potato vines crushing machine was designed in this paper. Based on the analysis of the whole structure, we expatiated on the working principle of the sweet potato crushing machine, and analyzed the structure of key components such as crushed parts, anti-wear technology, ground lifting mechanism and transmission mechanism. Before the machine started to work, the ground clearance needed to be adjusted based on the width and height of the ridge. The high ground clearance leaded to the long stubble height and poor operating effect, but the low ground clearance leaded to damage the sweet potato and increase power consumption. Sweet potato vines breaking qualified rate, stubble height and damaging rate were the main indicators of evaluating sweet potato vines crushing machine. The Box-Benhnken central composite experimental design principle was used on the basis of single factor experiment to study the working parameters of walking sweet potato vines crushing machine. The cutter roller speed, the ground clearance and the distance between blades were taken as three factors which influenced the working quality, and a three-factor and three-level response surface experiment was conducted. The mathematical model of the response surface was established, and the influence of each factor on the machine quality of the operation was analyzed and optimized. The result showed that when the roller rotation speed was high, the ground clearance was small and there was a moderate distance between blades. As such, the overall impact trend of the vines breaking quality rate was high and the stubble heights was low. When the roller rotation speed was small, the ground clearance was high and there was a moderate distance between blades, and the overall impact trend of the rate of the damage was small. The experiment results also showed that the order of the factors affecting of the vines breaking quality rate was: roller rotation speed >ground clearance >distance between blades The order of the main factors affecting of the stubble heights was: ground clearance >roller rotation speed >distance between blades The order of the main factors affecting of the rate of the damage was: ground clearance >roller rotation speed >distance between blades. In 2016, a three-time repeated test for verifying the exactness of the model was conducted on the Nanjing Research Institute for Agricultural Mechanization Ministry of Agriculture of Baima testing site. The field test showed that the optimum parameters were: 1950 r/min for the rotation speed, 25 mm for the ground clearance and 40 mm for the distance between blades, 94.88% for the rate of vines breaking qualified rate, 47.08 mm for the stubble heights, and 0.23% for the rate of damage. By comparing the mathematical model and the experimental result, the error range was less than 5%, which meant that the model established was reliable and could be used for optimization. The results can provide a reference for the structural design and optimization of the operating parameters of the walking sweet potato vines crushing machine. [ABSTRACT FROM AUTHOR]

The qualified index of original inside-filling air-blowing seed metering device could reach above 85% when working pressure was more than 5 kPa. In order to reduce the working pressure and energy consumption of fan and optimize the working effect of inside-filling air-blowing seed metering device, the installation position of combined compressed air nozzle was adjusted at first to make it as close as possible to the hole. The qualified index of seed metering device was only 82.73% when the working pressure was 2.5 kPa, and qualified index was reduced when increasing or reducing working pressure. Thus it can be seen that the installation position of combined compressed air nozzle has a significant influence on the sowing effect of seed metering device. In this paper, the bonded particle model was used to model maize based on theory of discrete element method, and the coupling analysis method of EDEM-CFD was applied to simulate the influence of different air nozzle installation positions on the working performance of inside-filling air-blowing precision seed metering device. Installation positions of combined air nozzle of structural parameter, inlet velocity and working speed of working parameter were selected as experimental factors, particle filling limiting velocity and filling time were used as evaluating indicators, the orthogonal experiment was carried out to optimize working performance of seed metering device. The results of variance analysis of filling performance showed that the influence of three factors on filling limiting velocity was significant (P<0.05) and on filling time was not significant (P>0.05). The primary and secondary factors that affect the filling limiting velocity was working speed > inlet velocity > installation position of combined air nozzle. A significant negative correlation (P<0.05) was found between filling limiting velocity and filling time and Pearson correlation coefficient was -0.785 (P=0.012). The results of variance analysis of cleaning performance showed that three factors had no significant (P>0.05) effect on qualified rate, reseed rate and leakage rate, but qualified index and filling limiting velocity were negatively correlated (P<0.05) when the combined air nozzle was in upper or lower position. The qualified index and filling limiting velocity was significantly positive correlation (P=0.01), the Pearson correlation coefficient was 1.00 and the significant level was 0.005. Therefore, in order to adapt to different working parameters of seed metering device, first of all, the installation position of combined air nozzle of structural parameters was optimized as the middle position. Bench test was performed to validate the simulation results. Double factor test of working pressure and installation positions of combined air nozzle was in progress when the working speed was 6 km/h, and compared with first generation seed metering device. Experimental results showed that the reseed rate of the installation position of combined air nozzle was lower than mille, but the upper position was opposite. The leakage rate of the middle installed position was better than the installation position of combined air nozzle and also was better than the installation position of combined air nozzle at the lower and upper positions. That is, the seed metering device has the best effect when the installation position of combined air nozzle was the middle, and the qualified rate of seed metering device was higher than 90% under all working pressure. The double factor test was carried out when the installation position of combined gas nozzle was at the middle with working speed of 4-12 km/h and working pressure of 3-7 kPa. Results showed that the seed metering device was easier to reseed at lower working pressure and lower working speed, it was easier to leakage at higher working pressure and higher working speed. On the whole, the qualified rate of seed metering device was higher than 90% under suitable working conditions. [ABSTRACT FROM AUTHOR]

The collecting machinery of mulching plastic film offers an important technological means to curb the farmland residue pollution. The main method of residual film recycling in Xinjiang is the raking-film working. Due to the complex cotton field environment and the poor raking film effect of whole profiling of the used plastic film collector, the raking film tooth can not simultaneously carry out the monomer film collecting with copying with different cotton field terrain, which causes a low collecting rate during the process of residual film recycling. For the problem, this paper proposed a collecting-film mechanism of the profiling of the monomer. The theoretical design and mechanical analysis of the mechanism of collecting film were carried out. With the method of complex vector, the profiling-mechanism dynamics model was established, which involved the relationship between the reacting force of soil to land wheel of profiling and the spring-tooth resilience force. Based on the establishment and analysis of dynamics model, the collecting-film influencing factor could be initially determined. And the relevance of the spring-tooth stress states and the raking-film mechanism's operating condition was further explored. In order to confirm the operation parameters of the device of collecting film, the experiment of the response surface with 5 levels and 3 factors was accomplished on the soil bin trolley test-bed with the spring tooth of the raking film. Three test parameters, i.e. spring tooth number, test-car speed and spring tooth diameter, were chosen as the influence factors of the test-bed experiment. And collecting rate of residual film recycling was selected as the evaluation index of the test-bed experiment. Quadratic orthogonal rotation combination trial design was applied to build the quadratic polynomial regressive model, which interpreted the relationship between the experimental influence factors and evaluation index. Using the data analysis software of Design-Expert 8.0.6, the matching mathematical regression pattern was developed, the relation of salient factors with the evaluation index was analyzed, and the parameters of test were improved. The optimum combination of parameters could be reached when the number of spring teeth was 5, the diameter of spring tooth was 12 mm, and the speed of test car was 1.85 m/s. By using the soil bin trolley testing, the optimized results were verified on the basis of optimization parameters combination. The experimental consequences manifested that the collecting-film rate of the mechanism of monomer profiling raking-film was more than 88.5%, the optimization prediction model based on the quadratic multinomial fitting model was reliable, and the film recycling requirement could be met by the structure and working parameters combination. According to the standing cotton stalks standard field experiment in Changji, Xinjiang, the experimental cotton field was selected, which was pressed by the wheel of picking cotton locomotive and produced different fluctuation of pits and soil slope, and the results from the cotton field and the laboratory were basically consistent. The research provides an original theoretical reference for the design of raking film mechanism of single profiling, as well as the parameter optimization of remnant plastic film collector. [ABSTRACT FROM AUTHOR]

In order to better realize the combination of agricultural machinery and agronomy, the design of precision rice hill-drop drilling machine was further optimized and tested. The precision rice hill-drop drilling machine that was powered with high speed transplanter chassis was composed of frame, furrowing and ridging device, height and horizontal profiling mechanism system, power transmission system, seeding device and hydraulic lifting frame. It could meet the rice direct seeding agronomic requirements which are furrowing and ridging synchronously, adjustable sowing rate and hill space, optional row space, profiling seeding mode and stubble burying before seeding. The combined hole-type metering device included small and big type holes was used for the precision rice hill-drop drilling machine, so that it could meet the sowing rate requirement of conventional rice and hybrid rice simultaneously and adjust the seeding rate quickly. On the basis of the combination of agricultural machinery and agronomy as well as the experimental verification, the frame, reduction gearbox, horizontal profiling mechanism, height profiling system and installation angle of slide plate were optimized. The new frame could protect the main bar from being bended. The new reduction gearbox made the hill space to match the speed of the chassis more accurately and also could change the rotation direction to fit different kinds of chassis. The height and horizontal profiling mechanism made the seeding machine more floatable, so it could adapt more complicate ground. Furthermore, the related experiments proved that profiling system is conducive to the seedling emergence of rice. The seedling emergence rates of the rice varieties XS134 and PZTF, which were seeded by the precision rice hill-drop machine with horizontal profiling mechanism, were 7.8% and 8.7% higher than that without horizontal profiling mechanism, respectively. In order to protect the atmosphere environment, the government introduced the relevant policies and laws to prohibit the burning of straw, and promoted the comprehensive utilization of crop straw. Many farmers returned straw residue to field to improve soil fertility and reduce environmental pollution, but it could be more difficult for the direct seeding machine and rice transplanter working in the field as well. To overcome this difficulty, the stubble-burying seeding was studied. The angle of the slide board was confirmed as 4° by the experiment result, while the efficiency of stubble burying was 91.6% and the furrowing and ridging effect under 4° was relatively better than that under other degrees. In this paper, some verification tests involved the main technical indices of the seeding machine and its reliability. Results showed that, the pure work efficiency was 0.67 hm2/h, the qualified rate of hill space was up to 100%, the variable coefficient was as low as 2.5%, the qualified rate of the seeds number per hill reached 95% and the cavity rate was 0; furthermore, the variable coefficient of the consistency of seeding quantity per row and the stability of total seeding quantity were 3.8% and 1.5% respectively; after seeding with horizontal profiling mechanism, the height difference between the left and the right field surface was about 2.0 cm; more important, the average of assignment before first-time fault (MTTFF) was 30.4 hm2/h, and the validity reached up to 98.2%. Therefore, on the basis of these results which all meet the national standard and the requirements of the combination of agricultural machinery and agronomy, and the reduction gearbox makes the machine+ more universal. The performance of the optimized precision rice hill-drop drilling machine is reliable and has exciting application foreground. [ABSTRACT FROM AUTHOR]

In the process of planting Anthurium andraeanum, people need to transplant the seedling from small pot to big pot to get more growth space. This work will not only spend much time, but also increase the cost of planting. Our research group has finished a design of the transplanting machine to realize the automatic transplanting of Anthurium andraeanum. However, during the usage of the machine, we found that the transplanting manipulator cannot take out the soil matrix completely from the small pot sometimes. Once the incomplete soil matrix is watered after the transplanting, the seedling will tilt. It will lead to the difficulty of sale. So taking out the soil matrix completely from the small pot will be one of the most critical technical problems in the transplanting mechanical system for potted anthurium. Operation objects can be regarded as rigid body in the traditional mechanism design, however, the potted soil matrix, as the operation object of transplanting manipulator, belongs to the discrete body, although the potted matrix can be condensed as a certain shape under the limitation of the pot. In the process of sinking the needle into the soil matrix and taking it out, it is hard to keep the original stable shape and take out the matrix completely due to the lack of the cohesion of matrix itself and the adhesion effect between the pot and matrix. This condition will lead to the failure of transplanting. Based on the discrete element analysis method, this paper established discrete element simulation model among mechanism (transplanting manipulator), action object (matrix with rootstock), and action condition (pots) by EDEM (enhanced discrete element method) software to analyze the whole process of transplanting. In the simulation, we found that when the transplanting manipulator takes out the soil matrix, a fault happens inside the soil matrix. After the analysis for this simulation phenomenon, we knew that when the total resistance force is greater than the maximum cohesive force that soil matrix can offer, the matrix will be broken and become the incomplete matrix. According to the above analysis, we started to use the Su-Field analysis method to solve this problem. By using the component analysis and functional model, the transplanting mechanical system was known more, and we focused the key point on the harmful adhesion effect between small pot and soil matrix. With the help of Su-Field model and standard solution, we fully analyzed the resources of the mechanical system and translated the Su-Field model into the solution of pot pressing mechanism finally. And for this solution, we also done the discrete element simulation by EDEM and found that the pot pressing mechanism can make a crack and reduce the friction between the soil matrix and pot. With the reduction of friction in this way, the total resistance force cannot be greater than the maximum cohesive force that soil matrix can offer most of the time. It will effectively avoid the appearance of incomplete soil matrix. So the solution of pot pressing mechanism is reasonable and feasible. On the basis of the solution, we done the optimization for the original transplanting mechanical system. The transplanting experiment of 3 groups of pots (100 pots each group) was carried out respectively for the transplanting manipulator before and after the optimization. We found that the success rate of taking out soil matrix completely is improved from 84.67% to 97.67%. In this study, the discrete element analysis and Su-Field analysis method in TRIZ (theory of inventive problem solving) are combined to apply to the mechanism optimization design process, which can provide reference for the research and development of automated transplanting equipment about potted plant. [ABSTRACT FROM AUTHOR]

With the increasing use of agricultural plastic film, the pollution it bringing is becoming more and more serious. It has become a problem which needs to be solved urgently. In China, the plant areas of peanut were expanded to 460.6 hm2 in 2014, which accounted for about 17.9% of the global area of peanut crops. And its output reached to 16.481 7 million tons in the same year, which accounted for about 38.9 % of the global production of peanut yields. Therefore, design and experiment on plastic film collector of ridged peanut means a great deal to us. The collecting film teeth residue plastic film collector of ridged peanut was designed, and the whole structure and working mechanism of the machine were introduced. Therefore, the main operation components of it were designed and the structure parameters were determined at last. To solve the problem of residual film recycling after peanuts harvest, we designed the plastic film residue collector, and then optimized its parameters. The key structural parameters were determined by mechanism analysis and tests. The collecting film teeth diameter of the first row, the second row, and the third row were set as 10, 8 and 8 mm, respectively. The harrowing tooth was made of No.65 manganese steel, and the harrowing tooth's lug angle ranges from 10° to 35°. The collecting film teeth space on the first row, the second row, and the third row were 120, 100 and 80 mm, respectively. The four-dimensional slice of MATLAB and response surface analysis was done on the machine speed, the harrowing tooth's lug depth and its radius of curvature. The quadratic regression model between film removing ratio and machine operating speed, the embedded depth of the rake, tooth curvature radius was built. The optimal structure parameters of plastic film residue collector were obtained by response surface analysis. The response surface analysis of the model was optimized, and the effect of 3 factors on the recovery of the residual membrane was significant. The order of strength is: machine operating speed> embedded depth of the collecting film teeth > collecting film teeth curvature radius. The machine was optimized by parameter optimization. The machine operating speed, depth of collecting film teeth, tooth's radius of curvature of machine was 1.2 m/s, 11mm, and 222 mm, respectively. And film recycling rate was about 93% through the field test. Its relative error was 2% compared with the predictive value. In conclusion, the optimization scheme was feasible. This paper could provide theoretical basis for optimization of related machines. With the preliminary experiment, the collecting film teeth residue plastic film collector of ridged peanut has good film quality, which meets the design requirements of plastic recycling machine. Removing mechanism on the collecting film teeth residue plastic film collector of ridged peanut is the further research. [ABSTRACT FROM AUTHOR]

Residual film not only affects the crop emergence and yield but also causes serious soil and environmental damage and affects the smooth operation of the agricultural machinery, so residual film recovery is imperative. Ridge tillage residual film recovery has the same characteristics with the residual film recovery equipment, and it has higher requirements for ridge width of residual film recovery equipment. The plastic film has not been fully utilized and the ridge body is relatively high. Furrow residual film recovery is difficult and a lot of plastic films used can not be completely recovered. A lot of plastic films are buried very deep. As one of the key means to control plastic film residue pollution, mechanically collecting technique of plastic film residue has shown a good developing prospect. But, there are many problems in the existing residual film recycling machines, such as high rate of film wrapping, incomplete recovery of residual film, and so on. Shovel screen type plastic film residue collector has a recycling capacity to the film in soil. It has a good application prospect in the field of ridge tillage plastic film recycling. The high rate of film wrapping for plastic film transport mechanism and the high rate of soil content in residual film after harvest are the major problems in the promotion of shovel screen type plastic film residue collector. To reduce the high film wrapping rate and soil containing rate in residual film after harvest, and improve the working quality of plastic film transport mechanism, single-factor test was used to get the best form of the screen surface structure in this paper. The Box-Benhnken central composite experimental design principle was adopted on the basis of single factor experiment to research the working parameters of the plastic film transport mechanism of shovel screen type plastic film residue collector. The vibrating screen's vibration frequency, vibrating screen amplitude, and distance between jagged pieces were taken as 3 factors which influenced the working quality, and a three-factor and three-level response surface experiment was conducted. In the experiment, when the vibration frequency of vibrating screen was less than 2.3 Hz, the separation effect was poor; when the altitude of vibrating screen was less than 40 mm, the film conveying performance was poor; when the distance between jagged pieces was less than 8 mm, the separation effect was poor; when the vibration frequency of vibrating screen was higher than 4.3 Hz, the resonance phenomenon was serious; when the altitude of vibrating screen was more than 80 mm, the effect of separation was poor; and when the distance between jagged pieces was more than 20 mm, the residual film phenomenon was serious. Therefore, the vibration frequency of vibrating screen was selected from 2.3 to 4.3 Hz, the altitude of vibrating screen from 40 to 80 mm, and the distance between jagged pieces from 8 to 20 mm. The mathematical model of the response surface was established. And the influence of each factor on the working quality was analyzed and each factor was optimized comprehensively. The results showed that the significant effects of vibration screen frequency, distance between jagged pieces and vibrating screen amplitude on reducing the rate of film wrapping were in a decreasing order, and the significant effects of distance between jagged pieces, vibrating screen amplitude and vibration screen frequency on reducing the rate of soil content were in a decreasing order. The best work parameters were as bellow: when the vibrating screen's vibration frequency was 3.9 Hz, the vibrating screen amplitude was 42 mm and the distance between jagged pieces was 15 mm, the rate of film wrapping was 1.72%, and the rate of soil content was 32.81%. Through comparing the mathematical model and the experimental result, it turned out that the relative errors of all the property indices between the two were less than 5%, which meant that the model established was useful and could be used for prediction and optimization. The research results can provide the references for the plastic film transport mechanism of plastic film residue collector and the optimization of working parameters. [ABSTRACT FROM AUTHOR]

In the intertillage of sugarcane, the fertilizing with a low evenness and stability will lead to many problems, such as losing a lot of sugarcane seedlings, soil hardening, fertilizer wasting, lower fertilizer use efficiency, and higher input with lower output. So the research on the fertilizing device is vital to control the evenness and stability of fertilizing. This paper focused on improving the fertilizing evenness of 3ZSP-2 type sugarcane intertillage fertilizing hilling machine. The innovational scraper fertilizing device was independently designed. The single-factor experiment on the diameter of disk, rotation speed of disk, gap of scraper, angle of scraper, width of scraper and advancing velocity was conducted in the Tropical Agricultural Machinery Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang in April 2014. The pivotal parameters of technology in this study were that the tractor motive power ranged from 22 to 36 W, the working speed ranged from 2 to 5 km/h, the overall dimension was 2300 mm × 1100 mm × 1640 mm, the diameter of fertilizer box was 730 mm, the diameter of disk was 700 mm, the rotation speed of disk ranged from 6 to 14 rpm, the width of scraper was 45 mm, the angle of scraper ranged from 15° to 19°, and the advancing velocity ranged from 0.7 to 1.1 m/s. The results showed that, the width of scraper, the angle of scraper and the advancing speed had a significant impact on the fertilizing evenness, and the value ranges of the 3 factors were identified. The mathematical model between the 3 experimental factors of the fertilizing device and the evaluation index of fertilizing evenness was established by the experimental method of Box-Behnken design. The influence law of those parameters on the evenness of fertilizer ejecting was analyzed through the Statistical Analysis System. The result concluded that the evenness of fertilizer ejecting increased at first, and then decreased respectively with the increasing of the 3 parameters (the width of scraper ranging from 30 to 50 mm, the angle of scraper ranging from 15° to 19° and the advancing speed ranging from 0.7 to 1.1 m/s). The order of the factors affecting the fertilizing evenness was the width of scraper > the angle of scraper > the advancing velocity. When the interaction was considered, the width of scraper and the advancing velocity had a tremendous impact on the target value, and the width of scraper and the angle of scraper also had a significant effect on the fertilizing evenness. Under the conditions of the width of scraper of 48.4 mm, the angle of scraper of 16.5° and the advancing velocity of 1.09 m/s, which were the optimal parameter combination, the fertilizing evenness was 92.97%, the stability of furrow opening depth was 92.9%, and the coverage rate of fertilizer was 100%. The verification test of optimized fertilizing device was performed in an experimental field whose area was 0.12 hm2. Results indicated that, the test result of the optimized machine was consistent with the results of the response surface analysis. The fertilizing deepness of this machine was 17.8 cm, the fertilizing evenness was 92.97%, and the coefficient of stability was 92.9%. All these indices were much higher than the design indices and the original machine, and met the requirements of cultivating, fertilizing and hilling in sugarcane tillage. The optimized mechanism parameters of fertilizing device were found to be technically viable. This study provides a starting point for further research on the optimization design of 3ZSP-2 type sugarcane intertillage fertilizing hilling machine. [ABSTRACT FROM AUTHOR]

Ride comfort is of great importance feature for the heavy truck, its optimization can improve the driver's driving conditions to reduce fatigue, and make the goods safer. Primary factors that can influence ride comfort are form and parameters of suspension, which are suspension stiffness, suspension damp and their combination. When the form of suspension is confirmed, more reasonable parameters can be selected by optimization method to improve ride comfort. Ride comfort optimization analysis belongs to the combinatorial optimization problem, at the same time, the nonlinear characteristics in optimization is essentially a nonlinear multimodal optimization problem. In this paper, at first, a nine degree of freedom vehicle vibration model was established; Vehicle driver seat acceleration simulation tests were conducted with different vehicle speed. Also, both time and frequency domain analysis was implemented with MATLAB software development platform. On the whole, with the increase of the speed of the vehicle, the acceleration root mean square of vehicle driver seat became larger, so the vehicle ride comfort performance reduced. Especially at low speed and high acceleration change is more obvious. But in 40~80 km/h, the acceleration change quite gentle. That means to achieve the better economy and the vehicle ride comfort performance, the vehicle speed keeping in a medium speed is better. Based on C level road and the speed of 70 km/h, with an eight by four dump truck as experimental object, the ride comforttests were conducted, moreover the test results compared with the results of simulation. The compared results showed that the simulation and the test were very close. And then, today technology was coming to a stage of intersection, infiltration, and interaction with multi subjects. More and more issues on complexity, non linearity, and system have come to us. To deal with such complexity of system, conventional techniques have become incapable, and to seek an optimization algorithm, which adapt to large scale parallel with intelligent characteristics, has been a primary research target of related subjects. The artificial fish algorithm was proposed to optimize ride comfort. The artificial fish swarm algorithm (AFSA), anew method based on animal behaviors and the typical application of behaviorism artificial intelligence, was proposed byan internal scholar in recent years. It used the operators such as prey, swarm, follow and random behavior. The algorithm parameters, such as population, step size, sense of distance, the largest try number, crowded degree coefficient and the largest number of iterations, has a great impact on the performance of the convergence. At the end, the artificial fish algorithm was used to optimize ride comfort by reasonable selection of the suspension parameters. The objective function was the acceleration root mean square of vehicle driver seat to be minimized. The decision variables were front suspension stiffness and damp. Moreover AFSA need to set up the appropriate algorithm parameters. For example, population scale, step size, sense of distance, the largest try number, crowded degree coefficient and the largest number of iterations was 100, 100, 20 000, 100, 9 and 50. Where the population scale N was called the number of possible values of suspension parameters within the value range, step size was suspension parameters increasing or decreasing the amount of each iteration, and sense of distance visual was variables scope of each iteration. Optimization results show that the acceleration root mean square average fell by 16.82%, the biggest fell by 21.24% in 60 km/h, so it effectively improves the ride comfort h performance of heavy vehicles. [ABSTRACT FROM AUTHOR]

In 2014, soybean production was 179 million tons, and planting area was 102.1 million square hectare in China. China has become the fourth largest soybean production country after the United States, Brazil and Argentina over the world. However, the green soybean harvest still rely on manual power, what’s more, harvesting has taken up the large part of labor force in green soybean planting, accounting for over 40% of the total labor force. The operation of pod taking off is a key link in the process of green soybean mechanization harvest, and meanwhile, it is a core factor and technology which seriously influences the equipment performances. The structure style of the device of pod taking off and its parameters selected for working directly determine its harvest capability of fresh soybeans and other legume crops. Therefore, a green soybean separation experiment device of 5TDS-00 type manufactured by Nanjing Research Institute for Agricultural Mechanization was designed to research the separation properties of green soybeans based on striking, in order to seek the optimal combination of the factors influencing the separation effect. This experiment device of pod taking off consisted of rollers of pod taking off , conveying mechanism, angle adjuster, distance adjuster, driving speed-adjusting motor, roller speed-adjusting motor and so on. The device was driven by motor and fed by chain conveyor, and could realize step-less speed regulation under the coordination of angle adjuster, distance adjuster and adjustable speed motor. After striking, the green soybean would generate the variable motion inertia force, which could overcome the pod-handle connection force so as to achieve the objective of separation. The energy collision model of the separation process and the mechanical model of pod-handle separation were constructed based on the principle of energy conservation. Quantitative analysis was done to verify the energy collision model and the mechanical model. The roller speed, feeding speed and roller distance were supposed to be the main influence factors. In the end, focusing on “Xiaonongqiuyan” and “Doutong 6” varieties, the experimental investigations were carried out. The test green soybean was derived from Hentang Export Vegetable Base in Changshu City, Jiangsu Province, and the sample collecting dates were from August 1st to 7th in 2014. Under the same climatic condition, the samples possessing the similar shape and quality could be chosen. After that the rapid refrigeration was needed and the storage temperature was set at -2-0℃. Moreover, the research should be completed within 24 h. The results showed that the crop variety had little impact on damage rate and separation rate. The order of the aggregative indicators according to their influence from major to minor was the roller speed, the feeding speed and the roller distance. When the roller speed was set at 600 r/min and the roller distance was set to 18 mm, and at the same time, the feeding speed was set at 0.3 m/s, the harvest rate could attain 99.0% and the damage rate could be reduced to 2.4%, achieving a good comprehensive property. The prototype field experiments showed that the production efficiency could be up to 3-5 mu every hour, which was more than 20 times the manual operation. The result of this paper can provide a theoretical foundation for the design of the green bean harvest device. [ABSTRACT FROM AUTHOR]

China is one of the major rapeseed production countries in the world, but the harvesting mechanization is still backward, and high mechanical harvest loss is a key inhibiting factor for rapeseed production. In order to reduce the harvest loss ratio, the effects of the parameters of air-screen cleaning device of rapeseed combine harvester on cleaning loss ratio and percentage of impurities in grain under the actual field harvest operating condition are needed to understand. In this paper, a Plackett-Burman test and a response surface test were designed to study the 4 parameters: vibration screen amplitude, crank revolving speed, fan revolving speed, and fan dip angle based on a two-roller and air-screen field mobile harvest testbed. The Plackett-Burman experiment results showed that the vibration screen amplitude and the crank revolving speed had significant influences on the cleaning loss ratio, and the effect of the amplitude was greater than that of the crank revolving speed, but the fan revolving speed and the fan dip angle had not significant impact; the results also showed that the fan revolving speed had significant influences on the percentage of impurities, while the other 3 parameters had not significant impact. The response surface regression variance analysis showed that the effects of the 4 parameters were not the linear relation but the interaction; the predicted values of quartic polynomial regression model were consistent with the measured values in the experiment, and the regression models of the cleaning loss ratio and the percentage of impurities were solved and the values of R2 were 0.9559 and 0.9660 respectively. The single factor and two-factor analysis results indicated that the vibration screen amplitude had a little impact on cleaning loss ratio near zero level, reducing the crank revolving speed could remarkably lower the cleaning loss ratio, and increasing the fan revolving speed could remarkably lower the percentage of impurities. A group of optimal parameter combinations under the constraint condition could be acquired by solving these regression equations, and a checking test was carried out by using an approximately optimal parameter combination: vibration screen amplitude of 35 mm, crank revolving speed of 392 r/min, fan revolving speed of 1 750 r/min, and fan dip angle of 29°. The cleaning loss ratio and the percentage of impurities were 0.90% and 0.45% respectively in the test, but when these parameters were applied into the regression mathematical models, the cleaning loss ratio was 0.38% and the percentage of impurities was 0.48%, and the absolute errors were 0.52% and -0.03% respectively. Compared with the field result that was based on the common parameters, the cleaning loss ratio dropped by 61% and the percentage of impurities dropped by 58%. The analysis results indicated that the relationship between the parameters of cleaning device and the cleaning loss ratio and grain percentage of impurities was correct and the precision of regression mathematical model could meet the need for optimizing the parameters of air-screen cleaning device. The results can provide theoretical basis and technical references for the parameter selection and optimization of air-screen cleaning device of rapeseed combine harvester. [ABSTRACT FROM AUTHOR]

In order to solve the problem of high traction resistance of the traditional subsoiler, a forced-vibration subsoiler was designed and developed. This paper introduced the structure and described the working principle of this forced-vibration subsoiler. What was more, the motion process of the vibrating deep loosening shovels was analyzed and the motion equation of the shovel point was established. Type of forward velocity, vibration frequency and vibration angle were selected as 3 factors of the orthogonal simulation experiment to evaluate their effects on traction resistance, total power and torque in the soil-bin experiment. The sequence of factors in affecting the traction resistance was vibration frequency > forward velocity> vibration angle. The traction resistance was reported to increase consistently with the increasing of forward velocity. The sequence of factors in affecting the total power was forward velocity > vibration frequency > vibration angle, and the total power values firstly increased and then decreased with the increasing of vibration frequency while the total power values firstly decreased and then increased with the increasing of vibration angle. The sequence of factors in affecting the torque was vibration frequency > forward velocity > vibration angle, and the torque values firstly increased and then decreased with the increasing of forward velocity while the torque values consistently increased with the increasing of vibration frequency. The optimal combination of the performance parameters was the forward velocity of 2 km/h, the vibration frequency of 10Hz and the vibration angle of 12°. For further validating the rationality of optimal combination of parameters, the test on working performance of the forced-vibration subsoiler was carried out in the experimental field, and soil properties (bulk density and water content), soil bulkiness, soil disturbance coefficient and traction resistance were selected as the evaluation indicators to compare with non-vibration subsoiler. The results showed that the bulk density of all soil layer decreased after forced-vibration sub-soiling and that at 0-15 cm soil layer decreased by 21.74%. At the same time, the water content at 15-25 cm increased by 16.02%. The variation coefficient and stability coefficient of sub-soiling depth, which were the indicators to the change quantity and degree, were 7.37% and 92.63% respectively. Meanwhile, the variation coefficient and stability coefficient of the depth reached the requirements of the Ministry of Agriculture, and the land surface was smooth and flat after sub-soiling. Moreover, soil disturbance coefficient was 57.11% after subsoiling and soil bulkiness was 36.96%. Both soil bulkiness and disturbance coefficient reached the requirements of the test indicators. In addition, the traction resistance was reduced by 9.09% compared with non-vibrating subsoiler, so the effect of reducing traction resistance was obvious. These results provide a reference for further optimization of the mechanical structure and improving dynamic and economic performance of the whole machine. [ABSTRACT FROM AUTHOR]