Contour tracking control in position domain

Abstract

Contour tracking is one of the most common control problems encountered by many industrial manipulators and robots to achieve high precision contour performance. In this paper, a new contour tracking control method developed in position domain is proposed aiming at improving the contour tracking performance. To develop the new control algorithm, a multi-axis motion system is treated as a master–slave cooperative motion system; the master motion is sampled equidistantly and used as a reference, while the slave motions are expressed as functions of the master motion according to desired contour requirements. A dynamic model of the multi-axis motion system represented in position domain is developed based on the master motion through one to one mapping from time domain to position domain. A PD type position domain control is proposed, and the stability analysis is conducted based on the Lyapunov function method. The developed position domain control is applied to contour tracking of linear motion and circular motion, and some comparison studies are performed between time domain control and position domain control. Simulation results demonstrate the effectiveness of the position PD control compared with traditional PD control and the crossed-coupled control.