惯性参数大范围变化机械伺服系统鲁棒跟踪控制

Robust tracking control of mechanical servo systems with inertial parameters varying in large range

机械伺服系统在执行不同任务时,要求能适应不同质量或惯量的工作负载.而工作负载的改变会导致伺服系统惯性参数的大范围变化,目前常见的运动控制方法,如PD控制,基于干扰观测器的鲁棒控制等,对上述情况表现为系统不稳定或跟踪性能变差.对上述问题,本文假定惯性参数变化范围已知,提出一种新型的非线性控制方法,用滑模技术实现了系统对惯性参数变化和外部扰动的鲁棒稳定性,和跟踪性能,引入边界层技术避免了控制切换产生的抖振现象.用Lyapunov直接法对系统的全局稳定性给出了证明,并分析了系统的暂态响应.以直流电机高精度位置伺服系统为例的仿真结果表明算法的有效性.

When implementing different tasks, mechanical servo systems must adapt to various working loads with different weight or inertia, which may lead to remarkable variation of servo system＇ s inertial parameters. In such cases, motion control methods at present,such as PD control and disturbance observer-based robust control,exhibit instability or tracking peffomaance declination. A novel nonlinear control scheme is proposed to deal with the above problems in known variation range of inertial parameters. The sliding mode technique is used for servo-system to achieve robust stability and guarantee transient response,and the boundasy layer control is also adopted to avoid chattering introduced by control switching. The servo-system＇ s global stability is then proved by using Lyapunov＇ s direct method, and the transient performance is analyzed. Computer simulation results developed for a DC motor servo-system show the effectiveness of the proposed method.