Sliding Mode Based Position Control of a Flexible-Link Arm

Abstract

In this study, sliding mode (SM) based partial feedback linearization (PFL) control method is applied to a single flexible link arm (FLA) with payload. A sliding mode based partial feedback linearization controller is designed to achieve set point precision positioning control for a FLA. Flexible robot arms have structural flexibilities and resulting high number of passive degrees-of-freedom. They cannot be decoupled due to the highly nonlinear structure. Since exact feedback linearization control methods cannot be applied to these systems, partial feedback linearization control methods are suitable for the flexible systems. For set-point control, sliding mode control based approach is applied to achieve the precise tip position of a single FLA. To do this, active and passive dynamics of the system are included in a new output equation and appropriate sliding manifold is defined using this new output equation. Proposed control algorithm is compared with PD based collocated PFL control method. Then, the performance of both controllers for the tip-position precision of a single FLA is demonstrated by simulations. Numerical simulations of a single FLA demonstrate that the SM based approach gives rise to a better performance than the PD based one.