Generally, FTC operation can be per

Generally, FTC operation can be performed by using either active fault tolerant control (AFTC) or passive fault tolerant control (PFTC) [6]. In the AFTC approach, the control system is reconfigured according to the fault estimation, which is obtained from a fault diagnosis observer [7]–[9]. However, the design of the additional FD observer increases the computational load of the system. In the PFTC approach, faults are compensated by the robustness of a robust controller without requiring fault estimation [10], [11]. One of the most advantages of the PFTC is that it can compensate the faults’ effects quicker that helps the system recovered from the fault states quicker. However, since the PFTC needs to counteract the highest faulty effects, the nominal controller of the PFTC should have high robustness [12]. Due to its inherent high robustness property, sliding mode control (SMC) has been extensively studied for many FTC systems [13]– [16]. However, there exists two major shortcomings in the design of the conventional SMC: (i) it provides a reaching phase, and (ii) it provides big oscillation, which is known as chattering. In order to handle the first shortcoming of the SMC, an investigation based on integral sliding mode control (ISMC) has been made [17]–[20].