Time varying trajectory control with bounded elastic modes of flexible manipulator

摘要

This paper treats the question of end point trajectory control of elastic manipulators based on the nonlinear inversion and predictive control techniques. Although, this approach is applicable to any elastic manipulator, for simplicity, a manipulator consisting of two rigid links and one elastic link is considered. First, an inverse control law is derived for the trajectory control of the Cartesian coordinates of the end effector. This inverse controller allows precise trajectory control, however, this causes divergent elastic mode oscillations. To suppress these flexible mode oscillations, a predictive control law is derived by minimizing a quadratic performance index which is a function of the predicted values of the tracking error, and the elastic modes, and the control inputs. This predictive controller is superimposed on the inverse controlelr to accomplish precise trajectory control with bounded elastic mode reponses. Simulation results are presented which show the trajectory control capability of the controller.