基于开环补偿与鲁棒控制的电液位置伺服加载系统研究

Electro-hydraulic position servo loading system based on open loop compensation and robust control

电液伺服加载系统往往存在大范围负载扰动和非线性干扰问题,采用传统PID控制策略一般难以解决,针对这一问题,为有效提高位置伺服的动态品质和稳态精度,提出了一种基于开环补偿与鲁棒控制的电液位置伺服加载系统。首先,介绍了一种电液伺服加载试验台系统的结构组成和数学模型;然后,阐述了扰动抑制的非线性开环补偿方法,分析了基于期望轨迹规划的位置开环补偿控制策略,以及在线预估系统非线性参数的特点,建立了位置伺服控制器的理论模型;阐述了位置伺服系统自适应鲁棒控制策略的模型和方法;最后,进行了电液伺服加载系统实验,验证了基于开环补偿与鲁棒控制的电液位置伺服加载系统的优越性。研究结果表明:与采用PID闭环方式的电液伺服系统相比,基于开环补偿与鲁棒控制的电液位置伺服加载系统的自适应性更强,位置跟踪曲线控制精度更高,当位置跟踪频率为20 Hz时,跟踪误差只有位置指令幅值的15%左右,系统的“双十”频宽可扩展到22 Hz,且其整体抗扰动性能明显也优于采用PID闭环方式的电液伺服系统。

The electro-hydraulic servo loading system often exist the problems of large-scale load disturbance and nonlinear disturbance,traditional PID control strategy is generally difficult to solve.Aiming at this problem,in order to effectively improve the dynamic quality and steady-state accuracy of position servo,an electro-hydraulic position servo loading system based on open loop compensation and robust control was proposed.Firstly,the composition structure and mathematical model of an electro-hydraulic servo loading test-bed system were introduced.Then the nonlinear open-loop compensation method for restraining disturbance was discussed,the position open-loop compensation control strategy based on expected trajectory planning was analyzed,the characteristics of on-line prediction of nonlinear parameters of the system were described,and the theoretical model of position servo controller was established.The principle and method of adaptive robust control strategy for position servo system were expounded.Finally,the electro-hydraulic servo loading system experiment was carried out to verify the superiority of the electro-hydraulic position servo loading system based on open loop compensation and robust control.The research results indicate that comparing with the electro-hydraulic servo system adopting PID closed-loop mode,the electro-hydraulic position servo loading system based on open-loop compensation and robust control has stronger adaptability,higher position tracking curve control accuracy,when the position tracking frequency is 20 Hz,the tracking error is only about 15%of the position command amplitude,the“double ten”bandwidth of the system can be extended to 22 Hz,and the overall anti disturbance performance is obviously better than the electro-hydraulic servo system with PID closed-loop mode.