Adaptive conditional integral sliding mode control for fault tolerant flight control system

A fault tolerant flight controller based on adaptive and conditional integral sliding mode control scheme for an aircraft with actuator faults is developed. Sliding mode controller (SMC) which has good performance for the systems with various uncertainties is used to deal with the actuator faults. Due to imperfect switching in practice, SMC raises the issue of chattering. When implemented using boundary layer, the controller can no longer guarantee zero steady-state error. In this study, (i) a conditional integral term is introduced to achieve zero steady-state error and (ii) the adaptive technique based on Lyapunov stability theory is adopted to compensate the effects of the disturbance generated by actuator faults. Numerical simulation results demonstrate high accuracy tracking performance via adaptive conditional integral sliding mode controllers without the fault detection and isolation process.