脱粒滚筒转速电液比例控制系统的设计与试验

Design and Experiment on Electro-hydraulic Proportional Control System for Rotational Speed of Threshing Cylinder

针对国内联合收割机脱粒滚筒链传动调速耗时多;带传动易打滑、维护成本高;控制系统多针对一种机型,且不能根据实际的工作状况,设定滚筒的转速等问题,设计了以PLC(可编程逻辑控制器)为核心控制器,以带死区的PID为控制算法,以液压驱动代替原有传动方式的转速控制系统,实现了对转速的自适应控制。仿真及台架试验结果显示:系统在转速发生变化时经过约5s跟踪到输入信号;加载后的调节时间约3.7s,超调量3.12%;负载增加(加载泵回路压力提高5 MPa),调整时间为4 s,超调量2.8 7%;负载减小(加载泵回路压力减小1 0 MPa),调节时间约为5 s,超调量3.3 7%。试验结果表明:转速电液比例控制系统稳定,在转速发生变化时的跟踪性能良好,调速误差范围小于5%,满足转速控制的要求。

In order to solve the problems such as the speed of the threshing roller chain drive of domestic combine harvester is much time-consuming; the belt drive is easy to slip and the maintenance cost is high; the control system is designed for a type of machine,and the speed of the drum can not be set according to the actual working conditions; This paper is designed with the PLC（ programmable logic controller） as the core controller,the dead zone of the PID control algorithm in hydraulic drive speed control system to replace the original transmission mode,realize the adaptive control of speed. The results of bench test show that the system is tracking the input signal after about 5 s when the speed changed.The adjustment time is about 3. 7 s and the overshoot is 3. 12%. When the load increased（ load pump circuit pressure increased by 5 Mpa）,adjustment time is 4 s,the overshoot is 2. 87%; load reduction（ loading pump circuit pressure reduced 10 Mpa）,the adjustment time is about 5 s,the overshoot is 3. 37%. The test results show that the electro-hydraulic proportional control system is stable,and the tracking performance is good when the speed changes,the speed error range is less than 5%,which meets the requirements of speed control.