大豆联合收获机作业参数优化

现阶段国内大豆联合收获机收获作业时由于脱粒、清选系统作业参数调整不当而导致大豆机收损失率、破碎率、含杂率较高。为解决这一问题,该文对影响大豆机收作业质量的相关参数开展田间试验研究,探索各参数对大豆机收作业质量的影响规律,探寻最佳作业参数组合。以机收损失率、破碎率、含杂率为目标,选择脱粒清选系统对作业质量影响较大的前进速度、滚筒转速、脱粒段脱粒间隙、分离段脱粒间隙、导流板角度、分风板角度、风机转速、上筛前部开度、上筛后部开度共9个因素,利用Box-Behnken中心组合试验方法,进行九因素三水平响应面试验,使用Design-Expert对试验结果进行响应面分析,探索各因素对试验指标的影响规律,并构建相关数学模型。试验结果表明:对大豆收获损失率影响较为显著的因素为风机转速、脱粒段脱粒间隙、前进速度、脱粒滚筒转速;对破碎率影响较为显著的因素为脱粒滚筒转速、脱粒段脱粒间隙、前进速度、导流板角度;对含杂率影响较为显著的因素为导流板角度、风机转速、分风板角度、上筛后部开度。通过多目标参数优化,确定最佳工作参数组合为前进速度6 km/h、脱粒滚筒转速450 r/min、脱粒段脱粒间隙25 mm、分离段脱粒间隙20 mm、导流板角度26?、风机转速1 260 r/min、分风板角度11.5?、上筛前部开度19 mm、上筛后部开度11 mm,此时损失率为0.24%、破碎率为0.90%、含杂率为0.14%,田间试验实测损失率、破碎率和含杂率平均值分别为0.24%、0.90%和0.14%,与优化值相对误差分别为0、4.7%和7.7%。研究结果可为大豆联合收获机结构改进和作业参数控制提供参考。

Optimization of working parameters of soybean combine harvester

Abstract: At present, there are few soybean harvesters dedicated to soybean harvesting in China, soybean harvesting mainly uses rice-wheat combine harvester by adjusting parameters and replacing working parts, and it is difficult to improve the efficiency and working quality of the soybean harvesting because of adjusting working parameters irrelevantly. To solve the problems, this experiment used a series of field trials to explore the influence of various key working parameters on the quality of soybean harvesting operations, and tried to figure out the optimal combination of parameters systematically. According to three indexes-- loss rate, crushing rate and impurity rate, nine factors of forward speed, rotate speed of roller, threshing gap in threshing section, threshing gap in separation section, angle of deflector, rotate speed of fan, angle of wind plate, front opening of upper sieve and posterior opening of upper sieve were chosen. By adopting the box-behnken central composite response surfaces analysis, we conducted the response surfaces experiments with nine factors and three levels. Then we used design-expert to analyze the response surfaces and built three mathematical models about loss rate, crushing rate and impurity rate. The research showed that rotate speed of fan, threshing gap in threshing section, forward speed and rotate speed of roller were the four most indispensable factors that affected the loss rate. Moreover, the four main factors influencing the crushing rate were rotate speed of roller, threshing gap in threshing section, forward speed and angle of deflector. Angle of deflector, rotate speed of fan, angle of wind plate and posterior opening of upper sieve played a decisive role in impurity rate. The response surfaces method was utilized to analyze the effects of factor''s interaction on loss rate, crushing rate and impurity rate, and the multi-objective optimization were conducted for the regression models to obtain the working parameters of best evaluation index. The working parameter combination of the soybean combine harvester with the lowest loss rate, crushing rate and impurity rate as constrains was thought to be optimal. In this model, the forward speed was 6.03 km/h, the rotate speed of roller was 452.02 r/min, threshing gap in threshing section was 24.93 mm, threshing gap in separation section was 20 mm, angle of deflector was 26°, rotate speed of fan was 1 261.63 r/min, angle of wind plate was 11.49°, front opening of upper sieve was 19 mm and posterior opening of upper sieve was 11.03 mm. Under this condition, the average values of loss rate, crushing rate and impurity rate were 0.24%, 0.86% and 0.13%. The results of verification experiment showed that the loss rate was 0.24%, crushing rate was 0.90% and impurity rate was 0.14% when the optimum parameters were adjusted to that the forward speed was 6 km/h, the rotate speed of roller was 450 r/min, threshing gap in threshing section was 25 mm, threshing gap in separation section was 20 mm, angle of deflector was 26°, rotate speed of fan was 1 260 r/min, angle of wind plate was 11.5°, front opening of upper sieve was 19 mm and posterior opening of upper sieve was 11 mm. The experimental value is in good agreement with the optimized value and the relative errors were 0, 4.7% and 7.7%. The research results can provide reference for structure improvement and operation parameter control of soybean combine harvester.