Continuous nonsingular terminal sliding mode contouring control of manipulator based on time delay estimation

In this article, a new nonlinear robust contouring control scheme is proposed for a planar manipulator. Compared with the end effector tracking error, contouring error is a more reasonable description of the minimum distance between actual position and desired contour when tracking a complex trajectory. Thus, the task coordinate contour error is selected to evaluate the tracking performance. However, most of the contouring control schemes are designed for biaxial gantry, the planar manipulator system is subjected to payload change, and the conventional contouring controller cannot solve this problem faultlessly. Here, the continuous nonsingular terminal sliding mode control and time delay estimation are integrated to develop a new contouring controller for large curvature trajectory high-speed tracking. The time delay estimation is adopted to estimate the manipulator dynamic and payload change. The tracking precision can be guaranteed even parameter uncertainty exsits. Furthermore, continuous nonsingular terminal sliding mode control is integrated with the contouring control to obtain faster convergence performance and robustness of the overall system. The proposed controller possesses obvious advantages, such as robust to payload change and a better performance when tracking a large curvature ellipse in high speed. The effectiveness of the proposed method is verified through simulation and experiment on a planar manipulator.