参数优化的高速开关阀控液压缸位置控制研究

Controlling Position of Hydraulic Cylinder with High-speed On-Off Valve Parameters Optimized

分析了高速开关阀在脉宽调制控制(PWM)下的流量特性,建立流量-压力方程、力平衡方程,在MATLAB/Simulink环境建立模型。充分利用了前馈控制的及时性和反馈控制的抗干扰性,解决纯反馈控制滞后性的问题,结合建立的位置控制模型,进行位置控制仿真,并对控制参数对位置控制特性的影响进行分析验证;针对位置控制参数人为整定的原因,利用遗传算法(GA)对速度前馈系数、位置反馈比例、积分系数和总控制输出系数进行寻优,得出了液压缸位移、速度、位置控制误差及高速开关阀PWM信号的占空比曲线。结果表明:1)高速开关阀在PWM控制方式下可实现对液压缸的流量控制;2)速度前馈-位移PI反馈位置控制算法可有效降低液压缸伸出过程中的位置误差;3)经遗传算法优化参数后的速度前馈-位移PI反馈的算法可实现液压缸精确位置控制,误差控制在-0.6 mm^0.6 mm内。

The flow characteristics of the hydraulic cylinder are analyzed with the pulse width modulation( PWM),and the equations of flow-pressure and force balance are studied in the environment of MATLAB / Simulink. This compound algorithm is proposed to realize the precise position control,under the condition that the duty ratio is given ahead. The PI algorithm is designed and utilized to deal with the position error with adjusting to the frequency and duty ratio of the high-speed on-off valve( HSV). The genetic algorithm( GA) is used to tune the control parameters such as speed-forward coefficient,proportional and integral coefficient of displacement feedback and output coefficient to obtain optimization results on the performance of the position control system. The hydraulic loop is established on the FESTO platform for verification through comparing simulation results with optimization results. The results and analysis preliminary show that: 1) HSV can realize the flow control with PWM method; 2) the compound algorithm of PI and speed feedforward-displacement feedback effectively reduces the position control error; 3) the position control algorithm optimized with GA can realize the precise position control,and the position error can be reduced within- 0. 6 mm ~ 0. 6 mm.