Passive actuator fault tolerant control for a class of MIMO non-linear systems with uncertainties

Fault Tolerant Control of affine class of MIMO non-linear systems have not received considerable attention of researchers compared to other class of non-linear systems. Therefore, this paper proposes an adaptive passive fault tolerant control method for actuator faults of affine class of MIMO nonlinear systems with uncertainties using sliding mode control. The actuator fault is represented by a multiplicative factor of the control signal which reflects the loss of actuator effectiveness. The design of the controller is based on the assumption that the maximum loss level of the actuator effectiveness is known. Further, since the proposed controller is adaptive, it does not require any a priori knowledge of the uncertainty bounds. The closed loop stability conditions of the controller are derived based on Lyapunov theory. The effectiveness of the proposed controller is demonstrated considering an example of a two degree of freedom helicopter and has been found to be satisfactory.