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Soybean is one of the most important grains and oil crops in China, due to a major source of oil and high-quality vegetable protein. It is very necessary to realize the low-loss harvest of soybean fields in the southern and Huanghuaihai regions. In this study, a 4LZ-1.5 type combine harvester was designed to consider the harvest of soybean breeding plots. The operation process was also theoretically analyzed for the soybean reel harvesting, according to the soybean pods easy to be fried at maturity. A numerical model was established for the reel structure and motion parameters. Some parameters were then optimized, such as the reel radius, reel speed ratio, and reel rotational speed. After that, the soil removal mechanism was optimized for the soybeans with the low pods and easy-to-shovel soil, according to the statistical parameters of soybean grain size. Furthermore, a soybean threshing and separation device was designed for the easy threshing and breakage of soybeans at maturity. The arrangement and distribution of the arch teeth were also determined via the increasing characteristics of the second-order arithmetic sequence. The angle of the deflector was adjusted for the various input amount. The blade fan-combined screen cleaning device was designed to optimize the structural parameters of the fan and cleaning screen. The pneumatic grain unloading device was designed to optimize the vortex fan. The plot harvesting required the high soybean mixed seeding, particularly for the breeding plot with a small planting scale and many varieties, compared with the field production. Frequent seed cleaning was required after harvesting to reduce the missed and mixed seeding, according to the harvest requirements of the breeding area. An optimization mathematical model was established to develop the seed cleaning device, together with the objective function and constraint conditions. A numerical simulation was then carried out using MATLAB, in order to determine the structural parameters of the seed-cleaning device. A series of comparative experiments in field harvesting were conducted in the Xinjiang Uygur Autonomous Region, Shandong province, and Hebei province of China. The better operating performance was achieved in the 4LZ-1.5 soybean combine harvester: the loss rate < 3.5%, broken rate < 1.5%, and impurity rate < 1%, fully meeting the soybean harvest requirements in most hilly areas. After harvest testing of 14 soybean varieties in a 3 m×6 m breeding plot, the test results were all achieved: the loss rate < 3.0%, broken rate < 1.5%, impurity rate < 1.0%, mixed seed rate < 0.2%, and the clearing time of 200-270 s, fully meeting the requirements of the harvesting operation indicators in the breeding plots. Compared with the existing soybean harvesting machinery, the harvest loss rate of 4LZ-1.5 soybean combine harvester was reduced by 1.5-5.0 percentage points, the broken rate was reduced by 3.5-6.5 percentage points, and the impurity rate was reduced by 2.0-7.0 percentage points. The findings can provide a strong reference for the structural optimization of operating parameters in soybean harvesters. [ABSTRACT FROM AUTHOR]

A header profiling system can be used to stabilize the header height during the operation of a combine harvester. The harvesting efficiency can be improved to protect the header from damage by stones and other debris in fields. It is very necessary to enhance the control accuracy of header height via the design of the mechanical structure, rather than only the header profiling algorithm so far. Therefore, this study aims to improve the sensitivity of the header profiling mechanism response to the topography change in the field, and the accuracy of field terrain profiling. A main-sub-plate pressing profiling mechanism was proposed, which was composed of a main profiling plate, an auxiliary profiling plate, a spring, an angle sensor, and a four-link transmission mechanism. Firstly, the geometric and mechanical models were established to determine the key parameters. Next, a quadratic regression universal rotary combination test was designed to optimize the key design parameters of the profiling mechanism. Among them, the test indexes were taken as the supporting force of header to the auxiliary profiling plate, the supporting force of soil to the main profiling plate, and the soil subsidence distance, whereas, the test factors were the spring stiffness coefficient, the initial length of spring, the weight of auxiliary and main profiling plate. A particle swarm optimization was selected to determine the level range of each factor. A multi-body dynamics and discrete element method (MBD-DEM) coupling was utilized to implement the optimization test for the MBD-DEM models of the main-subplate pressing profiling mechanism. A mathematical regression model was then established between each factor and index. It was found that the stiffness coefficient and the initial length of spring were the main influencing factors in the three response indexes. At the same time, a multi-objective comprehensive optimization was performed on various factors. The optimization goal was to make the supporting force of the header to auxiliary profiling plate as large as possible, whereas, the supporting force of soil to main profiling plate and the soil subsidence distance as small as possible. An optimal parameter combination was achieved as follows: the spring stiffness coefficient was 464 N/m, the initial length of the spring was 0.09 m, the length values of auxiliary and main profiling plate were 484, and 450 mm, respectively. The width values of the main and auxiliary profiling plates were 200 mm, and the material was 301 stainless steel. The spring material was carbon spring steel wire, where the wire and outer diameters were 2, and 20 mm, respectively, and the number of effective coils was 45. The field experiment results showed that the supporting forces of the header to the auxiliary profiling plate were all greater than 0 in the three repeated tests, indicating that the profiling mechanism was always in a normal working state. The average values for the supporting force of soil to the main profiling plate were 85.23, 85.80, and 86.08 N, respectively, which were basically consistent with the predicted values of the regression model, indicating that the profiling mechanism was sensitive to terrain changes. The average values of soil subsidence distance were 5.4, 7.1, and 6.4 mm, respectively, which were less than 10 mm, indicating the high accuracy of field terrain profiling. Consequently, the field experimental data was better consistent with the predicted values of the optimization model, indicating the reasonable parameter design of the profiling mechanism. Anyway, the reliable main-subplate pressing profiling mechanism can fully meet the requirements of soybean harvesting. The finding can also provide a strong reference for the profiling system of header in the combine harvester. [ABSTRACT FROM AUTHOR]

Grain threshing and separation are the main stages that cause grain breakage in the process of mechanized soybean harvesting. The harvest quality of soybean depends mainly on the configuration of threshing parts, particularly on the structural and performance parameters. In this study, a feasible threshing drum with replaceable components was proposed to investigate the influence of various factors in the mechanical process on the harvest quality of soybean. Lindou 11 was selected as the test material with a moisture content ranging from 10.1% -20.2% in the Linyi area. The impact of soybean machine harvest quality provided in-kind support. The arch teeth, ribs, and rod teeth were selected as the typical threshing components. The threshing drum with replaceable components was characterized by a unique drum spindle assembled by the replacing threshing bar unit and the adding fixed plate, as well as the drum shell in turn. Three types were obtained, including the rod-tooth, combined pattern rod/rod-tooth, and closed bow-tooth threshing drum. Experimental factors were selected as the forward speed, cylinder speed, threshing clearance, and angle of the guide plate. The evaluation indices of soybean were set as the seed crushing rate and un-depurated rate, according to the characteristics of soybean plants. A single factor test was designed to obtain the optimal working parameters of each influencing factor. Four factors were gained for the best drum structure and the optimal combination of operating parameters. A three-level orthogonal test was conducted to determine the significance of the influence of each influencing factor on the evaluation index. An evaluation test was designed to verify the accuracy of obtained data from the field test. The test results show that the forward speed and cylinder speed had a greater influence on the crushing rate, whereas, the cylinder speed and threshing clearance had a greater influence on the un-depurated rate. There was generally high threshing quality in the combined rod/rod-tooth threshing drum when the moisture content of soybean was in the range of 10.1%-15.4%.The influencing factors on the grain crushing rate were ranked in a descending order: the cylinder speed, forward speed, threshing clearance, and guide plate angle. The primary and secondary orders on the un-depurated rate were the cylinder speed, threshing clearance, guide plate angle, and forward speed. The threshing quality in the closed bow-tooth threshing drum was relatively high in the range of 17.8%-20.2% moisture content. The influencing factors on the grain crushing rate were as follows, the cylinder speed, forward speed, guide plate angle, and threshing clearance, where those on the un-depurated rate were in the order of threshing clearance, cylinder speed, guide plate angle, and forward speed. When the moisture content of soybean was in the range of 10.1% -15.4%, the combined bar-rod-tooth threshing drum was at a forward speed of 4km/h, a cylinder speed of 600r/min, a threshing clearance of 30mm, and a guide plate angle of 70°, where the crushing rate and un-depurated rate were the lowest, 0.90% and 0.18%, respectively. When the moisture content was in the range of 17.8%-20.2%, the closed bow-tooth threshing drum had a forward speed of 3km/h, the cylinder speed of600r/min, the threshing clearance of25mm, and the guide plate angleof75°, where the crushing rate and un-depurated rate were the lowest, 1.2% and 0.23% respectively, indicating an excellent harvest quality. The findings can provide a potential reference to design the promising threshing drum in a grain 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]

Aimed at the problem of high cleaning loss rate, impurity rate and secondary impurity rate due to improper adjustment of main operating parameters of wheat combine harvester double-outlet multi-dults cleaning device, single factor and multi-factor optimization tests that took feed amount, wind door opening, fan speed, upper and lower wind deflector angles as main test factors were conducted. The influences of each test factor on the cleaning loss rate, impurity rate, and secondary impurity rate were studied to find the optimal parameter combination. Firstly, referring to the relevant parameters of Kubota 988 model, which has a large amount of wheat harvester in the market, a test-bed with double air outlet multi-ducts for combine harvesters was built. When there were four ducts, the wheat cleaning loss rate 0.78% and impurity rate 0.48% were the lowest compared to the two or three ducts. Moreover, through single factor test of double air outlet four ducts cleaning device, the optimal range of feed amount was determined from 4.5 to 5.8 kg/s, wind door opening was 0°-20°, fan speed was 1 200-1 600 r/min, upper and lower wind deflector angles were 0°-20°. The results of single factor test showed that the cleaning loss rate increased with the increase of the feed amount and fan speed, and decreased with the increase of the upper and lower wind deflector angles; the impurity rate decreased with the increase of fan speed, and increased with the increase of the feed amount and upper and lower wind deflector angles; the secondary impurity rate increased with the increase of feed amount, and decreased with the increase of the wind door opening, fan speed and upper and lower wind deflector angles. The multi factor bench test and the orthogonal test with five factors and three levels were carried out by using the Box Behnken center combination test design theory. The regression equations about the cleaning loss rate, impurity rate and secondary impurity rate were obtained. The results showed that the factors of fan speed, feed amount, upper wind deflector angle had significant impact on the cleaning loss rate, the factors of fan speed, upper and lower wind deflector angles have impact on the impurity rate, and the factors of upper wind deflector angle, the fan speed and the feeding amount have significant influence on the secondary impurity rate. Through optimization of the target parameters, the optimal parameters combination were the feeding amount 4.5 kg/s, the wind door opening 10.2°, the fan speed 1 548 r/min, the upper and lower wind deflector angles 20° and 0°, at this time, the cleaning loss rate, impurity rate and secondary impurity rate were 0.79%, 0.40% and 0.82% respectively. Furthermore, the bench test under the optimal parameter combination condition was carried out to verify the accuracy of the optimal results. The results of bench test showed that the cleaning loss rate, impurity rate and secondary impurity rate were 0.75%, 0.38% and 0.76% respectively, and the error between test results and optimization results were 5.1%, 5.0% and 7.3% respectively. The results of this study can provide the references for the adjustment operating parameters and technical support for improving the performance of the multi-ducts cleaning device of the combine harvester. [ABSTRACT FROM AUTHOR]

: In view of the current situation that the cleaning sieve of the grain combine harvester is less applicable to soybean cleaning and the field performance test of soybean mechanical harvest is less, field performance tests of cleaning sieve of soybean harvest were conducted. We selected PRO688D as the field performance test machine and suike 20 as the soybean test variety. According to the preliminary experiments, researches of soybean combine harvester, the types and parameters of cleaning sieve which included upper, lower and tail sieve were determined. Selected conventional fish scale sieve, lengthened fish scale sieve, misplaced fish eye sieve, linear fish eye sieve and shell sieve as upper sieve, mesh sieve, round hole sieve and hexagonal hole sieve as lower sieve, and fish scale tail sieve and grid tail sieve as tail sieve. The vertical distance between two adjacent parallel sieves in the fish scale sieve is taken as the sieve plate opening of the fish scale sieve, and they were set as 26 mm, 28 mm and 30 mm. The cleaning loss rate and impurity rate during the field operation of the soybean combine harvester were used as the evaluation indexes of the soybean cleaning operation. Then, the field performance tests of cleaning soybean were carried out, and the data of the field performance test were analyzed and evaluated with the fuzzy comprehensive evaluation method. The optimization of the combination of sieve plate opening of fish scale sieves, upper sieves, lower sieves, tail sieves and cleaning sieves in the applicability of soybean harvesting was completed. The evaluation of cleaning operation level of different sieve plate opening of fish scale sieve showed that the cleaning operation level of fish scale sieve to soybean was the highest when sieve plate opening was 28mm. That is to say, when sieve plate opening was 28mm, the cleaning applicability of fish scale sieve to soybean was the best. The evaluations of the cleaning operation level of different tail sieve, upper sieve, lower sieve and combinations of cleaning sieve were conducted, the results of the cleaning applicability of different cleaning sieve to soybean were as follows: grid tail sieve was better than fish scale tail sieve; shell sieve and hexagonal hole sieve were the upper sieve and lower sieve with the best applicability for soybean machine cleaning. The highest level of cleaning sieves combination was that upper, lower and tail sieve were shell sieve, hexagonal hole sieve and fish scale tail sieve respectively. Cleaning sieve combination has the best cleaning applicability to soybean under the combination of shell sieve, hexagonal hole sieve and fish scale tail sieve. At this time, the cleaning loss rate of field performance test was 2.04%, and the impact rate was 0.53%. The results showed that the application of fuzzy comprehensive evaluation method to comprehensive evaluation of cleaning loss rate and impurity rate of different cleaning sieves and optimization of cleaning operation level could effectively improve the cleaning applicability of grain combine harvester to soybean. This study can provide the practical basis for solving the problem of low applicability of cleaning sieve to soybean, promote the field test and research on reducing cleaning loss rate and impurity rate of soybean combine harvester, and supply references for the research and development of cleaning device for soybean combine harvester. [ABSTRACT FROM AUTHOR]