Robust adaptive contouring control for biaxial feed drive systems

Contouring control is an effective method of providing precision machine tool control, and various such methods have been proposed to date. However, most existing methods require prior exact knowledge of feed drive dynamics. One of the authors has presented a robust contouring controller design that takes into account dynamics modeling errors and disturbances such as friction. Because this design is based on the variable structure control and requires the upper bounds of unknown parameter and disturbance magnitudes, unnecessary large values for the upper bounds deteriorate the control performance. This paper presents an extension of the robust controller to an adaptive version that has a real-time estimator of the upper bounds of unknown parameter and disturbance magnitudes. Comparative experimental results demonstrate the effectiveness of the proposed design.