A design of servo controller for nonlinear systems using state dependent Riccati equation

In this paper, we present a new servo controller for nonlinear manipulator system designed by using the idea of the model-following servo controller. The control method proposed does not require the linearization but can consider the internal forces at joints. In order to derive the nonlinear model including the internal forces at each joints during the control, the projection method proposed by W. Blajer et al.(1992) is employed. The nonlinear control input is given by repeated computation of the Riccati equation depending on the state, called State Dependent Riccati Equation. To verify the effectiveness of the approach, we have designed and realized the proposed tracking controller for two link SCARA type robot.