SLIDING MODE CONTROL OF VIBRATION IN A SINGLE-LINK FLEXIBLE ARM WITH PARAMETER VARIATIONS

A new sliding mode controller is formulated for the tip position control of a single-link flexible manipulator subjected to parameter variations. The system model, characterized by a non-colocated control system, is derived by using the assumed mode method. A sliding surface which guarantees stable sliding mode motion during the sliding phase is synthesized in an optimal manner. The surface is then modified to adapt arbitrarily given initial conditions for the reduction of the reaching phase. A discontinuous control law associated with the modified sliding surface is designed, prior to formulating a decoupled reduced order observer to estimate velocity state variables which are not available from direct sensor measurements. By using the proposed control law, fast and favorable system responses are accomplished through shortening the reaching phase. Furthermore, a low sensitivity to imposed uncertainties is obtained. Computer simulations are undertaken in older to demonstrate these superior control performance characteristics of the proposed methodology.