Fault-tolerant Control Based on Fixed-time Observer for a 3-DOF Helicopter System

In this paper, a fault-tolerant control (FTC) scheme is presented to counteract actuator faults, model uncertainties and external disturbances for a class of three degrees of freedom (3-DOF) helicopter. A fixed-time observer is introduced to estimate composite disturbances which results in a better tracking performance compared with other sliding mode observers (SMO). Finally, a novel control strategy is proposed via back-stepping design technique to guarantee the stability of closed-loop nonlinear system. Experimental results are given to show the effectiveness and advantages of the proposed method.