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Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the rapid development of agricultural aviation, electric multi-rotor unmanned aerial vehicles (UAV) for planting protection are favored in plant protection operations due to their advantages of vertical take-off and landing, air hovering, and easy operation. However, because of its low aerodynamic efficiency, there are currently problems such as low loading mass and short battery life, and it is still necessary to optimize and improve it. The lift characteristics is one of the important parameters for the performance test of the multi-rotor UAV. However, few tests have been conducted on the lifting characteristics of multi-rotor UAV. How do we comprehensively evaluate the lifting characteristics of various types of multi-rotor UAV and make comparisons and judgments on the performance of multi-rotor UAV. At present, there are no standards to follow. Only by clearly defining the evaluation index for lift performance, and by standardizing the test methods and evaluation criteria, the performance of the multi-rotor UAV can be judged and the suggestions for optimization and improvement can be given. Based on the existing research results, this paper considered the functional effectiveness criteria of helicopters combining economy, weight reduction, and heat transfer. A method of test and evaluation for the lift characteristics of the semi-tethered multi-rotor UAV is proposed. It includes performance testing semi-tethered platform, lift characteristics test method and index, and lift characteristics evaluation method. In order to verify the feasibility of the method, the performance test of 3 different models (four-rotor, Type I; six-rotor, Type II; and eight-rotor, Type III) was carried out. The test results show that the 3 models have great difference in power load, weight efficiency and thermal efficiency ratio. Type III is the best in power load, 7.6 mN/W larger than the worst Type I. The best Type I is 0.33 larger than the worst Type Ⅱ in weight efficiency. The best Type III is 10.5 N/°C larger than the worst Type I in thermal efficiency ratio. It reflects the difference in motor and propeller selection and structure of the 3 models of aircraft during the design process, thus showing difference in the performance of the whole machine. On the basis of the above index test, combined with the mathematical model of multi-rotor UAV power system, a scoring method is put forward to evaluate the lift characteristics of the multi-rotor UAV using the power load, weight efficiency and thermal efficiency ratio. The results of the comprehensive score of the 3 types are as follows: Type III > Type I > Type II. The results show that the proposed evaluation method can effectively evaluate the lift characteristics of different types of multi-rotor UAV. It can more objectively and accurately assess the technical level of multi-rotor UAV and strengthen the management of multi-rotor UAV in use. The test and evaluation method presented in this paper can not only be used to evaluate the performance of the multi-rotor UAV, but also provide a reference for the further improvement of the model performance. Of course, in the performance evaluation of multi-rotor UAV, the improvement of power load, weight efficiency and thermal efficiency ratio cannot be excessively pursued, and the balance of technical performance, reliability performance, safety performance, and economical efficiency should be upheld. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Under the full amount of straw returning mode for wheat-maize rotation cropping areas in Huang-Huai-Hai Plain of China, not only the wheat straw mulch in the field is large, but also it has good toughness, and the effect of straw grinding is poor. In addition, the soil is more viscous. When the field operation is driven by the traditional wheel drive, it is easy to have straw winding and congestion, which is easy to break when seeding. At present, the corn seeder mainly adopts the ground wheel driving seeder and pneumatic seeder, and the land wheel driving seeder is transmitted by the earth wheel, driving the seed row shaft to rotate and arrange seeds, When the field soil viscosity and straw coverage are large, the driving part can not work normally. Pneumatic corn planter is mostly used in large farms, which are more expensive and not suitable for domestic use. In order to reduce the rate of missed seeding and improve the precision of maize sowing, it is necessary to develop a reliable and active corn precision seed metering control system. To solve these problems effectively, this paper takes a common spoon-wheel corn seeding device in the market as the research object, and a kind of active electronic control corn seeding meter system is designed. This electronic control system consists of control box, touch display interface, rotary encoder, GPS speed sensor, brushless DC motor, driver and commutator reducer. When the system works, the USART HMI four-wire touch serial port man-machine interface is used to input the theoretical expectation of the controller to the controller, using the GPS speed sensor to collect the working speed of the machine, in combination with rotary encoder, and the operation speed of the feeder is collected in real time. To ensure the quality of work and improve the ability to resist interference, based on the double closed-loop fuzzy algorithm, the PID parameters are self-adjusted to get the target speed of seed metering device. The corresponding PWM duty cycle of the controller is adjusted to achieve the real-time control of the motor speed through machine operation speed and achieve precise seed metering. The results of bench test showed that the variation coefficient of the actual rotational speed was less than 10.0% when the theoretical rotation speed was 6 ~ 54 r/min, and the actual rotational speed was small in the vicinity of the theoretical rotational speed, which met the control requirements. When the speed was 3 ~ 5 km/h under the set spacing value, the plant distance qualified index was > 94.0%, and the leakage index was < 3.0%. When the vehicle speed was 6 ~ 8 km/h, the plant distance was greater than 90.0%, and the seeding index was less than 4.5%. Field validation results showed: under the full amount of straw returning mode for wheat-maize rotation cropping areas in Huang-Huai-Hai Plain, when the maize row control system was in operation, the qualified index was greater than 87.75%, and the average was 90.89%, and the seeding index was less than 4%, with an average value of 2.54%. In comparison with the common spoon-wheel corn seeding device in the market, the qualified index was increased by 2.12 percentage points, and the seeding index was decreased by 4.32 percentage points, and the seeding performance was good, which met the requirements of corn agronomic planting. Under the full amount of straw returning mode for wheat-maize rotation cropping areas in Huang-Huai-Hai Plain of China, not only the wheat straw mulch in the field is large, but also it has good toughness, and the effect of straw grinding is poor, and in addition, the soil is more viscous. In this paper, the research of electronic control system for seed meters for maize planting can effectively improve the quality of the row and provide a reference for the development of high speed actuator control system. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As an important type of non-road machinery, agricultural machinery plays an important role in national economy. At present, the main power source of agricultural machinery is diesel engine. However, the inherent combustion mode of diesel engine leads to large amounts of pollutant emission such as particulate matter (PM) and nitrogen oxide (NOx), and PM and NOx can cause great damage to human health and ecological environment. Therefore, exhaust emission control technology research for agricultural machinery is of great significance. From 3 aspects, this paper elaborates agricultural machinery emission legislation, individual technical routes to reduce agricultural machinery emissions, and combined technical routes to meet more stringent emission limits. Agricultural machinery emissions legislation part analyzes regulations of the EU (European union), the United States and China on exhaust emission limits, test cycles requirements, and their differences. The current agricultural machinery emission legislation for agricultural machinery in China is Stage III. Compared with the standard of Stage IV implemented by the EU and the standard of Tier IV implemented by the United States, exhaust emission limits of China III are relatively relaxed. Legislation of the EU, the United States and China for agricultural machinery increases the non-road transient cycle (NRTC) from Stage IIIB, Tier IV and China IV, respectively. Unlike the EU, China and the United States stipulate that agricultural machinery diesel engines of non-constant speed below 19 kW can also be tested under the cycle of 6 working conditions. In EU and China, the final measuring results of exhaust emissions consist of 10% of the cold start and 90% of the hot start, while the United States reduced the proportion of cold start test cycle results to 5%. Individual technical routes of agricultural machinery emission control mainly include oil technologies, engine purification technologies, and exhaust after-treatment technologies. Among them, oil technologies include improving the quality of fuel and lubricating oil, use of alternative fuels, and so on. Engine purification technologies include diesel engine optimization design for agricultural machinery, supercharging and supercharged intercooler, fuel injection optimization, and EGR (exhaust gas recirculation). Exhaust after-treatment technologies include DOC (diesel oxidation catalyst) technology, DPF (diesel particulate filter) technology and SCR (selective catalytic reduction) technology. Oil technology is a prerequisite for agricultural machinery exhaust emission control, while engine purification technology is the foundation. Advanced exhaust after-treatment technology is the key to meet stringent emission limits for agricultural machinery. Combined technology routes summarize the methods to meet China III and IV emission limits and the latest foreign emission limits. Diesel engines using the "optimized combustion + SCR" route save 5%-7% fuel compared with diesel engines using the "EGR + DPF/CDPF (catalytic diesel particulate filter)" route. Deducting urea consumption, the former route still saves 2%-3% fuel. "Optimized combustion + SCR" route is used in the EU commonly, while "EGR + DPF/CDPF" is usually used in the United States. Considering actual situation in China, there is still much room for improvement in fuel quality, but urea production is very common, so the implementation of China IV legislation prefers SCR. Of course, to find proper routes for agricultural machinery exhaust emission control, it needs to consider the power of agricultural machinery diesel engine, displacement and specific use of the environment, and other requirements. Finally, this paper summarizes the prospects of agricultural machinery emission control technologies. To meet the future China IV limits, it is a significant measure to install an exhaust after-treatment catalytic converter for agricultural machinery. Developing an integrated exhaust after-treatment catalytic converter with low cost and high purification efficiency may become an important research direction for the future emission control of agricultural machinery [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The banana stalks are rich in fiber, and the existing returning machines for banana straw and stubble crushed in China have generated a few problems such as overly severe cutting resistance, the fiber of banana straw winding crushing blade roller on the returning machine, working on the unstable condition and serious fuel consumption. In order to deal with the above problems which the existing choppers met with in the working process, with the help of theoretical study and the analysis on the planting model for banana in Hainan Province, this paper put forward a returning method that the moving knives on the front knife roller were used to crush banana straws and the flail knives on the back knife roller were used to break stubble under the earth. The rotational direction of stubble crushing roller in the returning machine was same to the forward direction of the machine providing power, while the rotational direction of straw crushing roller was contrary to that of stubble crushing roller. On the basis of establishing theoretical model and the analysis on the planting model for banana in southern China, the key shaped parameters of the sliding-cutting blade and the structural parameters of crushing blade rollers were determined respectively. Besides, the sliding-cutting and anti-twining returning device for banana straw was put forward. The overall structure and working principle of sliding-cutting and anti-twining returning device were described. The performance of crushing banana straw and the power consumption were evaluated by simulating the breaking operation of banana straw in farmland through a bench test driven by double electric motors. The machine was composed of electrical motors, a tractor powered by electricity, the frame of machines, the straw crushing device and the stubble crushing device. Through Design-Expert software, a quadratic orthogonal rotating experiment was performed. Based on the variance analysis and regression fitting, a multiple regression equation was gained, presenting the effects of the working speed of the returning device, the rotating speed of rotating roller of moving knives and the rotating speed of rotating shaft of stubble breaking on the qualified rate of straw crushing and power consumption. It could be seen that the rotating speed of rotating roller of moving knives had the most influential effect, followed by the rotating speed of rotating shaft of stubble breaking, and the working speed of the returning device had the least influence on the qualified rate of straw chopping. The operation condition was optimized by applying the response surface method. The optimum factors for straw and stubble crushing process were as follows: The rotating speed of rotating roller of moving knives was 1 600 r/min, the rotating speed of rotating shaft of stubble breaking was 500 r/min, and the working speed of the returning device was 1.39 m/s. Based on the theoretical analysis, the higher qualified rate of straw crushing was achieved under the faster rotating speed of rotating roller of moving knives. The smaller power consummation was obtained under the lower rotating speed of rotating roller of moving knives and the lower rotating speed of rotating shaft of stubble breaking. Under the optimal condition, the corresponding qualified rate of straw crushing and power consumption were 95.2%, and 4.96 kW, respectively. The differences between the experimental and the analytical values of the qualified rate of straw chopping and power consumption were 0.31 percentage points and 0.27%, respectively, which indicated that the software analytical value was in great agreement with the experimental value. And by field test, qualified rate of straw crushing of machine proposed in this paper was higher by 1.94 percentage points and power consumption was lower by 11.3%, compared with vertical flail banana stalk crushing machine. Its successful implementation can greatly improve the production efficiency for crushing banana straw and stubble on one hand, and on the other hand prevent the pollution brought by deserted banana straw putridity. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Proper dynamic modeling is essential for the design and control of paddy field levelers which maintains a level plow while working regardless field unevenness. The simplified rigid multibody method of dynamic modeling, of which modeling and simulation can be handled by hand generally, does not work well in that they do not produce satisfactory results, and there is not easily available method for verifying the simulation results. This paper proposes a flexible multibody approach for the paddy field modeling and simulation, and a method for model verification based on high speed camera measurement. For the former method, it is simplified to decide which bodies to be classified to be rigid or flexible and the related constraint types by studying the structure and theory of the multibody system, while leaving the tedious tasks of building differential-algebra equations and equation solving to the computer-based simulation tools; and the latter method features a non-contact, stereo image way to find the 3D (three-dimensional) position of center of mass and attitude angles of a rigid body through positioning multiple surface points. 1) Modeling. By analyzing the structure and summing up the past experiences, considering that the 3 parallel rods hanging the installation block and plow showed significant flexibility in many directions, a flexible multibody system with 2 rigid bodies (plow and installation block) and 1 flexible body (representing the 3 rods with a flexible beam) and 3 revolute joints in between was built. It was assumed that the tractor body was stationary, which helped to simplify the subsequent simulation and verification by reducing the flexible beam to be a cantilever beam. 2) Simulation. The MapleSim was used to perform the simulation. By introducing the main multibody library models, i.e. flexible beam, rigid body and rigid body frame, and following general modeling procedures, the leveler model was expressed into MapleSim environment. The model parameters were determined by measurement (for dimensions) and computer software like CATIA (computer aided three-dimensional interactive application) and ADAMS (automatic dynamic analysis of mechanical systems) (for mass values and inertial momentums). Among simulation results, curves for the position of the leveler's center of mass and inclination angle were produced. 3) Verification. Formulae finding the position of mass center and attitude angles of the plow by multiple surface points' 3D positions (at least 3 points that do not fall on the same straight line) were proposed, and the surface points' 3D positions were determined by the stereo imaging system composed of 2 high-speed cameras and the professional image analysis software TEMA. Laboratory tests on specially designed fixtures were conducted, which produced the plow's 3D position of mass center and its inclination angle as measured results to be used against the simulated results for model verification. The verification showed that the 2 kinds of results generally coincided with each other well, indicating that the modeling, simulation and verification method proposed is feasible and practical, though a closer check showed the inclination curves agreed quite well, but the position curves of mass center revealed a maximum deviation of 10 cm at times. Some causes for the difference were proposed. The method proposed in this paper, which includes modeling by structure analysis, simulation using software, and verification by measuring 3D position of center of mass and attitude angles of a rigid body using high-speed cameras, is feasible and applicable to similar mechanical virtual prototyping applications featuring modeling, simulation and verification. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The soil-covering and press wheel are the main parts of the corn planter, and their performances are directly related to the growth and the output of the corn. The device with the functions of soil covering and soil compaction can improve the soil moisture content after planting and simplify the structure of machine. The squeeze-type coverer is a typical device with the functions of soil covering and soil compaction. But due to that the contact area is too small to bring the poor stability of soil-covering and soil-compacting during work process, the squeeze-type coverer is often used on no-till planter. A new type of soil-covering and soil-compacting device for corn planter was designed in this paper. The device was composed of 2 soil-covering-pressing wheels with cone-shaped structure, and realized the functions of soil-covering and soil-compacting depending on the extrusion force of soil produced by soil-covering-pressing wheel during planting. The main structure parameters of the soil-covering and soil-compacting device were determined through theoretical analysis and experiment of double-disk opener, which were mean diameter of 350 mm, width of the horizontal part of single soil-covering-pressing wheel of 20 mm, width of the inclined surface of single cover-press wheel of 70 mm, and the value range of horizontal interval of left and right soil-covering-pressing wheel of less than 29 mm. The leaning angle of soil-covering-pressing wheel was determined through theoretical analysis of soil-covering process based on the shape of soil furrows, which meant the leaning angle was about less than 20°. Based on the agronomic requirement of soil-compacting, the range of external load was about 609-790 N. Through analyzing, it was found that the external load, the horizontal interval between left and right soil-covering-pressing wheel and the leaning angle were the main influencing factors on the functions of soil-covering and soil-compacting of the device. Taking the 3 indices as the experimental factors using Design-Expert software, the Box-Benhnken experiments of 3 factors and 3 levels were conducted, and the results showed that the order of the influence of the factors on the soil compactness in the top 5 cm soil layer of the seed furrow from high to low was the external load, the horizontal interval between left and right soil-covering-pressing wheel and the leaning angle. The order of the influence of the factors on thickness of covering soil was the leaning angle, the load and the horizontal interval between left and right soil-covering-pressing wheel. The optimal parameter combination of the device was the external load of 900 N, the horizontal interval between left and right soil-covering-pressing wheel of 13 mm and the leaning angle of 16°. Verification testing indicated that the soil compactness in the top 5 cm soil layer of the seed furrow was (43.8±1.9) kPa, the coefficient of variation was 4.3%, and the thickness of covering soil was (32.9±2.3) mm with the coefficient of variation of 6.9%. The soil-covering and soil-compacting device designed in this paper has good performance of soil-covering, soil-compacting and working stability. This study can provide a reference for the design of planters. [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]

Bearings are the important component of agricultural machinery and equipment, whose failure may seriously endanger the healthy operation of equipment and even lead to bodily injury. So the fault diagnosis of agricultural machinery and equipment gains more and more attention. Using the vibration signal to extract the fault characteristics is the most common method, but it is difficult to extract the weak fault characteristics in strong background noise. Therefore, the extraction of weak fault characteristics with very low SNR (signal-to-noise ratio) under strong background noise becomes the key to the fault diagnosis of agricultural machinery bearings. There are 2 general methods for weak feature extraction under weak background noise. One method is to extract weak faults from the perspective of suppressing or eliminating noise. The other one is not to eliminate noise but using noise to improve the SNR to extract the weak fault characteristics, such as stochastic resonance (SR) theory. Compared to the traditional noise reduction method, SR makes use of noise energy transfer to weak signal, so the weak fault characteristics are enhanced while some of the noises are weakened. Because of the excellent features of extracting weak fault characteristics in strong background noise, SR has become a hot topic for many scholars in recent years. In this paper, the weak fault characteristics extraction method of SR based on adaptive SVD (singular value decomposition) was proposed. In the method, firstly, the original signal was decomposed by singular value and reconstructed to obtain the component signal; the difference spectrum of mutual information was constructed, the mutual information of each component signal and the original signal was weighed, and the number of valid singular values was selected adaptively, in order to overcome the problem of existing methods including human subjective choice or only considering the size of singular values and other deficiencies. Using the mutual information difference spectrum, 3 and 10 effective singular values were obtained in the simulation signal and bearing outer ring signal, respectively. Secondly, the adaptive SR was performed for the component signal corresponding to the selected effective singular value which enhances weak fault characteristics. Finally, the enhanced component signals were statistically averaged to extract the weak fault characteristics. In this paper, constructing the mutual information differential spectrum, and considering the mutual information of the component signal and the original signal, on the one hand, it avoids the elimination of the useful signals; on the other hand, the adaptive selection is realized which avoids the subjectivity of the artificial selection. In addition, due to the presence of strong background noise, the larger singular value may have smaller mutual information, but it is not valid singular value. It indicates that large singular value does not necessarily contain useful information, and there may be noise interference. Hence, the selection of effective singular values should not be based on the size of the singular value. The above analysis shows that it is difficult to extract the weak fault characteristics by SVD in strong background noise. We combine the 2 methods to process the effective component signal selected by mutual information difference spectrum in SR, and the maximum spectral frequency of each component is obtained. The statistical average is used to achieve noise filtering in order to highlight the characteristics of weak fault frequency. The results of simulation and bearing outer ring test show that, the proposed method is superior to the SVD and SR method. The method can effectively extract 100 and 155.5 Hz weak fault characteristics respectively for simulation signal and bearing outer ring signal. The proposed method can be applied not only to the fault diagnosis of bearing in strong noise background, but also to provide reference for bearing fault diagnosis of agricultural machinery and equipment. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to study the damage and mechanism of corn during corn ear picking, this paper analyzed the force of corn ear when picking corn ear, and then found that there were 3 kinds of forces working on corn ear, which were the reacting force, the frictional forces of stripping roller and the force of stripping roller rib, and caused the corn ear damage with different forms. This paper made the mathematical model of forces, and analyzed their change law and their influence on the damage of corn ear. With the rising of corn ear diameter, the reacting force, the frictional forces of stripping roller and the seed loss increased. The experiments of corn ear picking were carried out on test bed. The results showed that the damage of corn seed increased as the length of corn ear was greater than 175 mm. Because with the increase of the corn ear, the center of gravity for corn ears was upward and the corn ear swing increased when it was picked, the probability of collision increased. The rate of corn damage descended as the rotating speed of stripping roller changed from 650 to 800 r/min. When the rotating speed of stripping roller was more than 800 r/min, the corn damage increased significantly. When the rotation of stripping roller became faster, the down velocity of corn ears became bigger, the impact between corn ear and stripping roller increased, and the corn damage rose. Besides, the reduction of friction between the maize straw and stripping roller was another reason for the increasing of corn damage. The corn seed loss rate decreased and then increased as the rotating speed of stripping roller changed from 650 to 750 r/min, and the corn seed loss rate decreased again as the rotating speed of stripping roller changed from 750 to 850 r/min. Because when the rotation of stripping roller became faster, the corn ear down speed became bigger, the impact between the corn ear and stripping roller increased. The corn damage and seed loss decreased and then increased as the stripping roller clearance changed from 8 to 15 mm. The corn damage and seed loss were the minimum when the stripping roller clearance was 10 mm, and then with the clearance of stripping roller increasing, the corn damage and seed loss ascended, which was consistent with the result of theoretical analysis. And the mechanical damage form of corn usually included corn nibbled, corn impacted, corn extruded and broken corn ear. The process of corn ear picking was recorded with the high-speed camera and the movement of corn ear was analyzed. The results indicated that the moving velocity of corn ear had no effect on corn damage. It was also observed from the record that the moving state of corn ear picking had 3 types: first, corn ear was picked smoothly and entered the conveyer device; second, corn ear bounced; third, corn ear picking became difficult or corn ear contacting stripping roller for a long time. And the corn ear damage became more serious with the increasing of the contacting time between corn ear and stripping roller. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)