基于观测器摩擦补偿的机电系统高精度控制

High precision control of electromechanical system based on observer friction compensation

针对机电作动系统在低速阶段摩擦非线性明显且同时存在其他干扰,易导致系统跟踪精度、稳定性下降这一问题,设计基于非线性观测器摩擦补偿的自适应鲁棒控制器.针对摩擦非线性,利用LuGre摩擦模型描述系统的摩擦现象,提出非线性观测器对模型的内部摩擦状态进行观测.针对系统摩擦系数、转动惯量及其他不确定性参数,设计参数自适应律进行估计.利用前馈补偿的方法,对摩擦非线性和参数不确定性进行补偿,设计鲁棒项克服系统的其他扰动.利用Lyapunov稳定性定理证明了提出的控制器在存在扰动的情况下可以实现系统的有界稳定性.实验结果表明,提出的控制器具有较高的控制精度与较强的鲁棒性,跟踪精度较传统的PID控制器提高了一个数量级.

An adaptive robust controller based on nonlinear observer friction compensation was designed aiming at the problem of obvious friction nonlinearity and other interferences in the electromechanical actuation system at low speed,which may easily lead to the decrease of system tracking accuracy and stability.The LuGre friction model was used to describe the friction phenomenon of the system for the nonlinearity of friction,and a nonlinear observer was proposed to observe the internal friction state of the model.The parameter adaptive law was designed for uncertain parameters such as system friction coefficient and rotational inertia.The friction nonlinearity and parameter uncertainty were compensated by feed-forward compensation,and robust terms were designed to overcome other disturbances in the system.Lyapunov stability theory was used to prove that the proposed controller can achieve the bounded stability of the system in the presence of disturbances.The experimental results show that the proposed controller has higher control accuracy and stronger robustness,which is an order of magnitude higher than the tracking accuracy of traditional PID controller.