Fault Mode Analysis and Convex Optimization-Based Fault-Tolerant Control for New Type Dissimilar Redundant Actuation System of Near Space Vehicle  
[PERSON]  
1 Beijing Institute of Automatic Control Equipment, Beijing 100120, China; [EMAIL_ADDRESS] (J.H. ); [EMAIL_ADDRESS] (W.L. ); [EMAIL_ADDRESS] (F.Z.) 2 School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (C.S.) Correspondence: [EMAIL_ADDRESS]  
[PERSON]  
1 Beijing Institute of Automatic Control Equipment, Beijing 100120, China; [EMAIL_ADDRESS] (J.H. ); [EMAIL_ADDRESS] (W.L. ); [EMAIL_ADDRESS] (F.Z.) 2 School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China; [EMAIL_ADDRESS] (D.L. ); [EMAIL_ADDRESS] (C.S.) [PERSON]  
1 Beijing Institute of Automatic Control Equipment, Beijing 100120, China; [EMAIL_ADDRESS] (J.H. ); [EMAIL_ADDRESS] (W.L. ); [EMAIL_ADDRESS] (F.Z.) 2 School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China; liudi54834@buaa. reliability of NT-DRAS, fault-tolerant control (FTC) technique is used to minimize effects of possible faults and maintain the system performance at a desired level. There are two types of faults that can occur in NT-DRAS: sudden faults and gradual faults. The sudden faults typically lead to distinct system performance degradation, resulting in effective fault identification which can be used to address its side effects [5]. Alternately, gradual faults, such as oil leakage and flow changes, are difficult to detect and can gradually degrade the system performance and pose a problem that remains to be effectively solved. FTC has evolved into two branches: passive fault-tolerant control (PFTC) and active fault-tolerant control (AFTC). [PERSON] and [PERSON] [6] have conducted a comparative study of the two different approaches, and discovered that PFTC can be used to deal with the predicted faults while AFTC can be used to deal with unknown failures which may lead to catastrophic consequences. PFTC is typically adopted for designing fixed controllers with robustness against presumed faults and disturbance, and although it is of limited fault-tolerant capability, it does not require fault detection and control law reconfiguration. [PERSON] and [PERSON] [7] studied the PFTC problem of a double inverted pendulum. For comparison purposes and for the case of critical faults, they applied AFTC with active reconfiguration of the control law. They concluded that both PFTC and AFTC can maintain high stability and level of performance when the system suffers critical faults, but that AFTC requires real-time fault detection and diagnosis information. For example, [PERSON] et al. [8] used AFTC in vehicle on the precondition of fault detection and diagnosis. [PERSON] studied the fault detection and isolation (FDI) and FTC problems in flight control system [9], and demonstrated the importance of FDI for the effectiveness of AFTC. For the complex and changing fault cases (including both minor and severe faults) of a system, PFTC and AFTC can be combined to develop comprehensive FTC strategies in different fault degree conditions [10]. [PERSON] [11] presented a literature review emphasizing essentiality of the FDI process in the AFTC design. Consequently, the PFTC approach can be considered to be a better one when dealing with the reliability of FDI and the fault features in NT-DRAS systems with only gradual faults. The robust control techniques are often used to address the FTC problem. For example, in order to maintain system performance under severe conditions such as actuator faults, robust control techniques can be used to develop a linear parameter varying (LPV) controller [12]. The efficiency of parameter identification with the robust control technique can be further improved with the adaptive technique [13], in which case the fault modes are modeled following the fault principles. For example, [PERSON] et al.