GAIN SCHEDULED H-INFINITY CONTROLLERS FOR A 2 LINK FLEXIBLE MANIPULATOR

The dynamics of a two link flexible manipulator are highly nonlinear a nd vary with the configuration of the second link over the operating r ange of the manipulator. This fact makes it difficult for a single lin ear time invariant controller to achieve the desired closed-loop speci fications. This paper investigates the use of robust gain scheduled H( infinity) controllers for endpoint trajectory tracking of a two link f lexible manipulator with the angular position of the second link used as a scheduling parameter. A new method of gain scheduling with guaran teed stability at all frozen intermediate operating points is proposed . The method exploits the explicit and observer based compensator form of H(infinity) controllers resulting from the normalized coprime fact or robust stabilization approach. Simulation results corresponding to straight line motion of the tip of the second link are shown to illust rate the use of the proposed method.