Model reference FTC for LPV systems using virtual actuators and set‐membership fault estimation

Abstract

In this paper, a model reference fault tolerant control (FTC) strategy based on a reconfiguration of the reference model, with the addition of a virtual actuator block, is presented for linear parameter varying (LPV) systems. The advantage of the proposed FTC method is that the control system is reconfigured in such a way that the nominal controller is used without the need of retuning it. Moreover, the presence of saturations is taken into account through their incorporation in the reference model, and the introduction of additional varying parameters, such that the system exhibits some graceful performance degradation when the system could not achieve the desired state because of the actuator limits. The design of the control scheme is based on linear matrix inequalities (LMIs) and polytopic LPV techniques. In order to implement the proposed active FTC strategy, a fault estimation is required. In this paper, the fault estimation is formulated as a parameter estimation problem, which is solved using a set-membership approach. An aeronautical application is used to assess the performance of the proposed approach.Peer ReviewedPostprint (published version

Fault tolerant control of a proton exchange membrane fuel cell using Takagi–Sugeno virtual actuators

“…In this situation, it is important to ensure/enhance the robust stability of the closed-loop system under errors in the fault magnitude estimation [41,42]. Following the ideas introduced in [43], the more realistic case whereˆ (k) / = (k) andû(k) / = u(k) will be discussed hereafter. By considering (k) =ˆ (k) + (k) and u(k) =û(k) + u(k), where (k) and u(k) are the uncertainties in the estimation of the multiplicative actuator faults and the stuck actuator faults, respectively, and taking into account that:…”

Fault tolerant control of uncertain dynamical systems using interval virtual actuators

“…Moreover, the possibility of faults affecting the system is not taken into account, which makes the approach in Efimov et al fragile. The main original contribution of this paper is the extension of the idea developed in Efimov et al to the case of fault tolerant tracking, which allows overcoming the above‐mentioned limitations and which is done taking into account the theoretical results presented in Rotondo et al To achieve this, the reference model approach is extended to the use of interval observers, by considering an error feedback controller that uses the estimated bounds for the error between the real state and the reference one; the virtual actuator approach is extended to the use of interval observers, which means that the virtual actuator is added to the control loop to preserve the nonnegativity of the interval estimation errors and the boundedness of the involved signals, in spite of the fault occurrence. …”

Fault diagnosis and robust fault-tolerant control for linear over-actuated systems

“…So far, the fault estimation approaches which consider the physical limitation of the faults are really limited. 14,15 On the other hand, most modern safety-critical systems are equipped with some redundant actuators which make the control system over-actuated and it has attracted many researchers' interests. [16][17][18][19] Due to the redundant actuators, it is not easy to achieve fault isolation in the over-actuated systems.…”

“…In recent years, several AFTC methods using virtual actuator have been proposed and successfully applied to different systems, such as linear time-invariant systems, 25 piecewise affine systems, 26 Lipschitz nonlinear systems, 27 Hammerstein-Wiener systems, 28 and LPV systems. 13,15 However, the virtual actuator-based AFTC for over-actuated systems has received little attention. For over-actuated systems, only the control allocation methodology is used to distribute the desired FTC action over the available actuators.…”