Optimal sliding mode controllers for spacecraft attitude manoeuvres

This paper studies optimal sliding mode controller designs using integral sliding mode control (ISM) to deal with some spacecraft attitude control problems. Integral sliding mode control combining the first order sliding mode and optimal control is applied to quaternion-based attitude control for rest-to-rest manoeuvres with external disturbances. In the optimal control part, the state dependent Riccati equation (SDRE) approach and control Lyapunov function (CLF) are used to solve the infinite-time nonlinear optimal problem. The second method of Lyapunov is used to show that asymptotic stability is achieved. An example of rest-to-rest attitude manoeuvres is presented and simulation results are included to verify and compare the usefulness of the various controllers.