高速开关阀控电液位置伺服系统自适应鲁棒控制

Adaptive robust control of electro-hydraulic position servo system using high speed on/off valve

为研究高精度的液压缸位置跟踪控制问题,设计了高速开关阀和换向阀组合控制液压缸的结构方案,并通过实验分析了高速开关阀的静态流量特性。建立了液压缸的连续可微摩擦模型,利用粒子群优化算法对其参数进行辨识。建立了系统的非线性数学模型,基于非连续参数映射和反步法设计了直接自适应鲁棒控制器,通过参数在线自适应调节来更新估计值和鲁棒反馈项支配参数不确定性,实验结果表明:在跟踪幅值为5mm,频率为0.4Hz的正弦信号时,最后一个周期的最大跟踪误差、平均跟踪误差及其标准差分别为0.638、0.25mm和0.405mm,与传统PID控制器相比,控制精度显著提升,旨在为实现高精度的数字阀控位置伺服技术提供有价值的参考。

A electro-hydraulic position servo system based on a high speed on/off valve(HSV)and a directional valve was designed to obtain the high-precision position control of hydraulic cylinder using HSV,in existence of large parametric uncertainties and nonlinearities.Static flow characteristic of HSV was analyzed to choose appropriate experiment frequency.Nonlinear model of hydraulic system was established with friction model and the parameters of continuous differentiable friction model were identified by particle swarm optimization(PSO)algorithm.Direct adaptive robust controller(DARC)was proposed based on nonlinear projection mapping technology and back-stepping control theory.Parametric uncertainties and nonlinearities were handled by parameter online adaptation and robust feedback in DARC.Experimental results showed that the proposed controller achieved higher control performance which was better than proportion integration differentiation(PID)controller.In tracking a sinusoidal trajectory with amplitude of 5 mm,frequency of 0.4 Hz,the maximum tracking error was 0.638 mm,average tracking error was 0.25 mm,and standard deviation of the tracking error was 0.405 mm during the last cycle.This method would be ofvaluable guiding significance to the development of digital servo control system.