Position domain contour control for multi-DOF robotic system

Contour tracking control is one of the fundamental operations for robotic systems. In this paper, a position domain PD control is developed to control a multi-DOF nonlinear robotic system for improving contour tracking performance. In this new position domain control system, a robotic system is viewed as a master–slave system where the master motion is used as an independent reference through equidistantly sampling, while slave motions are described as functions of the master motion according to contour tracking requirements. A position domain dynamic model of the robotic system based on the master motion is developed through one-to-one mapping of the original dynamic model from time domain to position domain. Stability analysis is conducted for the proposed position domain PD control, the global boundedness of the tracking errors is guaranteed through the Lyapunov method, and the effectiveness is successfully verified through simulation study for linear and nonlinear contour tracking problems. Compared results demonstrate that the position domain PD control is better than its time domain counterpart for contour tracking of multi-DOF robotic systems.