Adaptive Fault Tolerant Attitude Control for Heavy-lift Launch Vehicles with Input Nonlinearities

Abstract

This paper proposes a novel effective adaptive fault tolerant attitude controller for a class of HLVs (Heavy-lift Launch Vehicles) subject to external disturbances, actuator nonlinearities and faults. The dead-zone nonlinearities of the actuator, accidental actuator gain faults and deviation faults are all under consideration in this paper. In order to guarantee the accurate attitude stabilization and tracking, a fault tolerant control scheme with two adaptive parameters is constituted, which is able to estimate the lower boundary of the nonlinear actuator effectiveness, the nonlinear dead-zone parameters and external disturbances. As a result, the synthesized adaptive fault tolerant attitude controller can work well in the presence of the disturbance, actuator nonlinearities and faults. The proof of the convergence is accomplished on the basis of a quadratic Lyapunov function. The simulation results are presented to demonstrate the effectiveness and advantages of the proposed adaptive fault tolerant control method.