玉米免耕播种机镇压力精准调控系统设计与试验

Design and Experiment of Precision Control System for Compaction Pressure Force of Corn No-tillage Planter

摘要:

针对玉米免耕播种机播种镇压力稳定性差和镇压强度不均等问题，设计了一种基于PID控制的镇压力精准调控系统。该系统由镇压力检测单元、液压调节装置、控制器、终端和机械执行部件组成。基于拉力传感器、角度传感器测量数据，采用Origin软件构建镇压力与两传感器测量数据之间的关系模型。系统通过镇压力进行闭环反馈，应用PID控制算法计算控制变量，实时调节液压缸伸缩，实现对镇压力的精确控制。系统阶跃响应测试结果表明，镇压力精准调控系统调节时间均值为1.13s，稳态误差均值为2.7N，超调量均值为3.23%。田间试验结果表明，当设定目标镇压力为159、182N、播种机作业速度为5～9km/h时，基于液控调节方式下镇压力相对误差为3.08%～5.38%，均方根误差为6.63～10.09N，机械调节方式下镇压力相对误差为5.05%～11.48%，均方根误差为11.67～22.49N。基于液控调节方式的播种机试验指标显著优于基于机械调节方式的指标，提高了镇压力稳定性，为保障玉米免耕播种质量提供了技术装备支撑。

Abstract:

In response to the practical issues of compaction pressure poor stability and uneven compaction strength in corn no-till seeder, a precise control system for compaction pressure was developed based on PID control. The system consisted of a compaction pressure detection unit, hydraulic regulation device, controller, terminal, and mechanical actuator. By utilizing measurement data from tension sensor and angle sensor, the relationship model between the compaction pressure and the measurement data of the two sensors was established by Origin software. The system employed the PID control algorithm to calculate control variables and adjust hydraulic cylinder extension and retraction in real-time, thereby achieving precise control of compaction pressure. Step response experiments revealed that the system’s mean adjustment time was 1.13s, with the mean steady-state error of 2.7N and the mean overshoot of 3.23%. Field experiments demonstrated that the relative error of compaction pressure under hydraulic control mode was 3.08% to 5.38%, with root mean square error of 6.63N to 10.09N，when the target compaction pressures were set at 159N and 182N, and the seeder’s operating speed ranged from 5km/h to 9km/h. In contrast, the relative error of compaction pressure under mechanical adjustment was from 5.05% to 11.48%, and the root mean square error was from 11.67N to 22.49N. The performance metrics of the seeder based on hydraulic control significantly outperformed those based on mechanical control, enhancing the stability of compaction pressure and providing technical and equipment to ensure the quality of notill sowing of corn.