Predictive End Point Trajectory Control of Elastic Manipulators

The paper presents an approach to end point trajectory control of elastic manipulators based on the nonlinear predictive control theory. Although this approach is applicable to manipulators of general configuration, only planar flexible multilink manipulators are considered. A predictive control law is derived by minimizing a quadratic function of the trajectory error of the end points of each link, elastic modes, and control torques. This approach avoids the instability of the zero dynamics encountered in the controller design using feedback linearization and variable structure control techniques. Furthermore, the derived predictive controller is robust to uncertainty in the system parameters. Simulation results are presented for a one link flexible manipulator to show that in the closed-loop system accurate end point trajectory control and vibration damping can be accomplished