Contour error control of CNC machine tools with vibration avoidance

A vibration avoidance and contouring error compensation algorithm for feed drives is presented. The residual vibrations are avoided by applying input shaping filters on the reference axis commands. The input shaping filter avoids the excitation of the structural modes but at the expense of increasing tracking and contouring errors. The tracking errors are estimated from the closed loop transfer function of drives, and used to predict the contouring errors which are mapped to the each axis for pre-compensation. The integrated vibration avoidance and contouring error compensation is experimentally demonstrated to improve the damping and contouring accuracy on a two-axis table.