电液位置伺服系统的变速趋近律滑模控制抖振抑制

Chattering Inhibition of Variable Rate Reaching Law Sliding Mode Control for Electro-hydraulic Position Servo System

针对指数趋近律变结构控制应用于电液位置伺服系统存在控制性能与抖振不能兼顾的问题,设计出新型变速指数趋近律滑模控制器。建立基于偏差变量的电液位置伺服系统状态空间模型,推导出指数趋近律滑模控制器结构,进一步确定包含偏差变量的切换函数及其导数,通过定义系统的Lyapunov函数,证明了趋近律控制下系统的稳定性。研究通过实时分析运动点距离滑模面的位置及趋近速率,采用模糊参数优化策略动态调整到达速度的变速趋近律方法,实现在滑模面外时加快响应速度并增强系统克服摄动及外部干扰能力,到达滑模面时柔化控制量以消除抖振的目的。通过试验研究变速趋近律与传统指数趋近律控制下的系统方波跟踪动态响应、稳态误差及控制量抖振指标,结果表明变速趋近律不仅保证到达运动的快速性,且有效降低了稳态抖振,具有良好的稳态性能。

It is difficult for exponential reaching law variable structure consideration to both control performance and the chattering in electro-hydraulic position servo system, a new type of variable rate exponent reaching law of sliding mode controller is designed. The state space model on the deviation variable is established for electro-hydraulic position servo system, derive the structure of the exponential reaching law sliding mode controller, to further determine the switching function and its derivatives containing the deviation variable, by defining lyapunov function of the system, prove the stability of system under reaching law control. By real-time analysis the distance of moving point with sliding surface and reaching rate, the arrival speed is dynamically adjusted by fuzzy parameter optimization, the purpose for speeding up response and overcoming the perturbation and external disturbance out of the sliding surface and weakening control to eliminate chattering near the sliding surface. The square wave tracking dynamic response, steady-state error and control chattering indicators on the strategy are studied between variable rate reaching law and traditional exponential reaching law by experiment, the results show that the variable rate reaching law strategy not only guarantees the arrival movement speed,.but also effectively reduces the steady-state chattering, has good steady-state performance.