Sliding-Mode Tracking Control With DNLRX Model-Based Friction Compensation for the Precision Stage

This paper concerns the development of a sliding-mode tracking controller with friction compensation for a precision positioning stage with cross-roller guides. Experiments including prerolling and rolling friction regimes are conducted, and then a two-stage parameter estimation algorithm is used to identify the parameters of a friction dynamic model (Dynamic NonLinear Regression with direct application of eXcitation, DNLRX, model). This model allows the estimation of the friction force in combination with the system dynamics against displacement, and can be used as a feed-forward controller to compensate for the friction effect. To compensate for model error and uncertain disturbances, an integral sliding-mode controller with a disturbance estimation scheme is designed and combined with the DNLRX feed-forward controller to control the motion of a precision stage. Experimental results show that with the proposed controller, tracking performance can be improved.