高速免耕玉米播种单体镇压力主动调控系统设计与试验

Design and Test of Active Control System for Soil Compaction of High Speed No-tillage Maize Planter

摘要:

针对高速免耕播种条件下镇压系统稳定性难以保障问题，提出镇压力主动调控技术方案，设计了基于电液控制的玉米播种单体镇压系统。提出系统总体结构方案，并通过对播种单体运动和镇压部件与土壤互作力学分析，确定了镇压力控制过程。完成了电液控制系统设计和硬件选型，分别采用AMEsim仿真分析和阶跃响应试验，开展了液压执行机构和电控系统设计，采用自动PID控制方式，系统调节时间均值为1.9s，稳态误差均值为1.9N，超调量均值为2.0%，均明显优于机械调节方式。开展了正弦曲线地表土槽验证试验，对比研究不同调节方式和地表条件对镇压力稳定性的影响，结果表明：当目标镇压力为300N时，相较传统的机械调节方式，电液控制方式镇压力均方根误差平均低30.1%，种沟土壤坚实度变异系数平均低24.46个百分点；正弦曲线地表竖直方向上的最大位移分别为0、20、40mm时，随着目标镇压力增加，镇压力均方根误差变化不显著，最大差值为39.2N。基于电液控制的玉米播种单体镇压系统能够在不同地面条件下保障镇压作业质量，该研究可为旱区播种作业过程中湿润种床构建以及高速免耕条件下玉米播种提供技术和装备支撑。

关键词:玉米播种机;镇压力;电液控制系统;高速;免耕

Abstract:

It is difficult to guarantee the stability of soil compaction system under the condition of high speed no-tillage seeding. Therefore, a technical scheme of automatic soil compaction control was proposed, and the electro-hydraulic control system for soil compaction of maize planter was designed. The overall structure of the system was proposed, and the pressure control process was determined through the mechanical analysis of the movement of the seeding monomer and the interaction between suppression wheel and soil. The electro-hydraulic control system design and hardware selection were carried out. AMEsim simulation analysis and step response test were used respectively to design the hydraulic actuator and electronic control system. The results showed that compared with the traditional mechanical regulation, the adjustment accuracy and stability of the hydraulic actuator using PID control were improved. The mean adjustment time of the control system for soil compaction was 1.9s, the mean steady-state error was 1.9N, and the mean overshoot was 2.0%. It was obviously better than mechanical control. Sinusoidal surface soil trough verification test was adopted, and comparative experimental study was carried out on the influence of different adjustment methods and surface conditions on the stability of soil compaction. The results showed that when the target pressure was 300N, the RMSE of the pressure using electro-hydraulic control was 30.1% lower on average and the variation coefficient of soil compaction was 24.46 percentage points lower than that by using traditional mechanical control. When the maximum surface displacement in the vertical direction of sine curve was 0mm, 20mm and 40mm, respectively, the variation of RMSE was not significant with the increase of the target force, and the maximum difference was 39.2N. The automatic soil compaction control system of maize planter based on electro-hydraulic control can guarantee the compaction operation quality under different work conditions. It provided technical and equipment support for the construction of seed bed and maize sowing under the condition of high speed and no tillage in arid region.

Key words:maize planter;compaction pressure;electro-hydraulic control system;high speed;no-tillage