中文摘要：

考虑电液系统的强非线性特点,提出了一种基于液压无源性理论的非线性鲁棒控制方法。该控制方法利用跟踪误差的滑模与液压无源性理论中的压力误差储能函数构建Lyapunov函数,backstepping逆向递推过程分解为位置跟踪与压力跟踪两个环节,为了化解电液系统中两个控制容腔的压力内动态所造成的冗余自由度难题,提出了基于稳态工作点的期望压力分配策略,从而推导出非线性鲁棒控制律。在样机系统上的实验结果表明,被试电液系统在跟踪0.2~20 mm/s速度范围内指令轨迹时跟踪误差的均方根均在5μm以内,基于液压无源性的非线性鲁棒控制方法实现了良好的跟踪性能与性能鲁棒性。

英文摘要：

Taking into account the strong nonlinearity associated with the dynamics of the electrohydraulic system,a passivity based nonlinear robust control method was developed for it. In the proposed method,the Lyapunov function was designed with the sliding mode of tracking error and the pressure error storage function constructed in the hydraulic passivity theory. Thus the backstepping design process can be decomposed into two cascaded steps： position tracking and pressure tracking. The electrohydraulic system has a redundant dimension,as the two chambers of the hydraulic actuator have different areas. The added internal dynamics of pressure also brought the stability issue. To handle this difficulty,a steady state working point based assignment strategy was presented. This strategy combines force and flow constraint conditions,such that it can assign unique desired pressure for each chamber of the hydraulic actuator. As a result,the nonlinear robust control law was synthesized. Experiments were carried out on a prototype system to validate the effectiveness of the proposed method. The experiment results show that with the developed controller,the electrohydraulic system achieves accurate tracking. The error is no more than5 μm,while tracking constant speed and sinusoidal trajectories. The proposed control method presents good tracking performance and performance robustness.