Control for tip trajectory tracking of a planar flexible link manipulator

Tip trajectory control of a flexible manipulator is complex because of the coupled nonlinear dynamics and non-minimum phase nature. The objective of tip trajectory control is to achieve desired tip trajectory tracking and suppress the vibrations of the tip. In this paper, two types of controller for a single link planar flexible manipulator are proposed. The first controller is a stable inversion control which is based on stable inversion technique that converts the non-minimum phase system into stable minimum phase by solving internal dynamics. This controller consists of feed forward compensator derived using stable inversion technique and a robust feedback control to stabilize the unmodeled dynamics. The second controller is based on nonlinear adaptive control derived using sliding mode technique. The analysis of closed loop asymptotic stability of two controllers is performed using Lyapnuov function. A planar single link experimental setup is designed to validate the proposed controllers. The performance of the two controllers is compared with additional payload mass on the tip.