Robust adaptive attitude tracking control of rigid spacecraft with deadzone nonlinearity

The main problem addressed is the attitude tracking control of rigid spacecraft with deadzone nonlinearity in the presence of an unknown inertia matrix and external disturbances. A robust adaptive control scheme is presented without constructing the deadzone inverse. One salient feature of the proposed controller is that it is independent of any prior information on the deadzone widths, inertia parameters and external disturbances. The stability proofs are given to show that the derived controller is adaptive to deadzone widths as well as inertia parameters and robust to bounded disturbances. It is also shown that the controller ouarantees small tracking errors and bounded deadzone parameter estimates. Numerical simulations are performed to demonstrate the effectiveness of the proposed robust adaptive control algorithms.