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1

Observer-based sliding-mode fault-tolerant consistent control for hybrid event-triggered multi-agent systems

Xia Dexian, Fu Xingjian

International Journal of Applied Mathematics and Computer Science

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2024

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Vol. 34, no. 3

361--373

EN

An observer-based hybrid event-triggered sliding mode fault-tolerant consistent control strategy is proposed for actuator faults in nonlinear second-order leader-follower multi-agent systems. A fault observer is designed to obtain the velocity and additive fault of the agents at the current moment. In order to save network resources and avoid the proliferation of actuator fault information, a hybrid event-triggered mechanism is given based on the actuator fault output from the fault observer. Then, a sliding mode fault-tolerant control strategy is investigated based on the speed and hybrid event-triggered mechanism of the fault observer output and combined with a linear sliding mode surface. As a result, the multi-agent system can still realize state consistency when there is an actuator fault. Conditions under which the consistent error of the multi-agent system is bounded are given. Finally, the effectiveness of the designed fault observer, sliding mode fault-tolerant controller, and hybrid event-triggered mechanism is verified by simulation in a leader-follower multi-agent system connected by a directed graph.

2

Fault tolerant control and fault diagnosis methods integrated using intelligent controller for hybrid dynamic systems

Achbi Mohammed Said, Rouabah Boubakeur, Mahboub Mohamed Abdelbasset, Benarabi Bilal, Kafi Mohamed Redouane, Kechida Sihem

Diagnostyka

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2024

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Vol. 25, No. 3

art. no. 2024312

EN

This research aims to provide a fault diagnosis approach for Hybrid Dynamic (SDHs), Systems and FaultTolerant Control synthesis, while also ensuring the smooth operation of industrial settings. This study is a part of the larger topic of Hybrid Dynamic System control and fault diagnosis. The primary focus is on modelling strategies designed expressly for Hybrid Dynamic Systems, with a concentration on combining continuous and event-driven components. Much work is devoted to developing a model that can incorporate both kinds of elements. A system model that can track several modes without explicit identification can be created by utilizing Neuro-Fuzzy Networks, providing a thorough overview. On the basis of this synthesized model, an AI-based fault diagnosis method is subsequently developed.

3

Power quality enhancement in double fed induction generator using iterative learning control

Djaidja Oussama, Mekki Hemza, Zeghleche Samir, Djerioui Ali

Przegląd Elektrotechniczny

|

2023

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R. 99, nr 7

41--48

EN

This paper presents a combination of the proposed Sliding Mode Control and a newly developed iterative learning control technique for harmonic compensation for the fault’s effect to adjust the active and reactive power to their desired references. The classical SMC cannot deal with the effect of the faults that can achieve graceful system degradation. Indeed, when there are significant disturbances, the input control signal of the SM controller is gradually adjusted by the ILC harmonic compensator in order to reject the disruptive harmonics effectively. Simulation results are given to demonstrate the effectiveness of the suggested SMC-ILC in terms of active and reactive power responses. The obtained results illustrate that the SMC-ILC strategy is valid and capable of ensuring a ripple-free operation in the presence of faults. The proposed controller is characterized by its simple design, robustness, and efficiency, which are convincing for practical application and may be used as a solution to the current Fault Tolerant Control.

PL

W artykule przedstawiono kombinację proponowanej regulacji trybu ślizgowego i nowo opracowanej techniki iteracyjnego sterowania z uczeniem w celu kompensacji harmonicznych w obecności zwarć, aby sterować mocą czynną i bierną zgodnie z ich pożądanymi wartościami odniesienia. Klasyczny SMC nie radzi sobie ze skutkami usterek, które mogą doprowadzić do płynnej degradacji systemu. Rzeczywiście, gdy występują znaczne zakłócenia, wejściowy sygnał sterujący kontrolera SM jest stopniowo regulowany przez kompensator harmonicznych ILC w celu skutecznego odrzucenia zakłócających harmonicznych. Przedstawiono wyniki symulacji, aby pokazać skuteczność proponowanego SMC-ILC w zakresie odpowiedzi mocy czynnej i biernej. Uzyskane wyniki pokazują, że strategia SMC-ILC jest poprawna i zdolna do zapewnienia działania bez tętnień w przypadku wystąpienia usterki. Proponowany sterownik charakteryzuje się wytrzymałością, wydajnością i prostą konstrukcją, które przekonują do praktycznego zastosowania i mogą być stosowane jako alternatywa dla dotychczasowych Kontrola odporna na awarie.

4

A new improved control for power quality enhancement in double fed induction generator using iterative learning control

Djaidja Oussama, Mekki Hemza, Zeghlache Samir, Djerioui Ali

Diagnostyka

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2023

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Vol. 24, No. 3

art. no. 2023309

EN

This work presents a new Fault Tolerant Control approach for a doubly fed induction generator using Iterative Learning Control when the fault occurs. The goal of this research is to apply the proposed ILC controller in conjunction with vector control for doubly fed induction generator to enhance its reliability and availability under broken rotor bars. However, the performances of classical VC control are often characterized by their inability to deal with the effects of faults. To overcome these drawbacks, a combination of VC control and iterative learning control is described. The input control signal of the VC controller is gradually regulated by the ILC harmonic compensator in order to eliminate the faults effect. The improvement of this approach related to active and reactive power ripples overshoot and response time have been explained. Which active and reactive power response time have been reduced more than 84% and 87.5 % respectively. The active and reactive power overshoots have been reduced about 45% and 35% respectively. The obtained results emphasize the efficiency and the ability of the proposed FTC to enhance the power quality in faulty condition.

5

Reliability-aware zonotopic tube-based model predictive control of a drinking water network

Khoury Boutrous, Nejjari Fatiha, Puig Vicenç

International Journal of Applied Mathematics and Computer Science

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2022

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Vol. 32, no. 2

197--211

EN

A robust economic model predictive control approach that takes into account the reliability of actuators in a network is presented for the control of a drinking water network in the presence of uncertainties in the forecasted demands required for the predictive control design. The uncertain forecasted demand on the nominal MPC may make the optimization process intractable or, to a lesser extent, degrade the controller performance. Thus, the uncertainty on demand is taken into account and considered unknown but bounded in a zonotopic set. Based on this uncertainty description, a robust MPC is formulated to ensure robust constraint satisfaction, performance, stability as well as recursive feasibility through the formulation of an online tube-based MPC and an accompanying appropriate terminal set. Reliability is then modelled based on Bayesian networks, such that the resulting nonlinear function accommodated in the optimization setup is presented in a pseudo-linear form by means of a linear parameter varying representation, mitigating any additional computational expense thanks to the formulation as a quadratic optimization problem. With the inclusion of a reliability index to the economic dominant cost of the MPC, the network users’ requirements are met whilst ensuring improved reliability, therefore decreasing short and long term operational costs for water utility operators. Capabilities of the designed controller are demonstrated with simulated scenarios on the Barcelona drinking water network.

6

Integrated fault-tolerant control of a quadcopter UAV with incipient actuator faults

Kantue Paulin, Pedro Jimoh O.

International Journal of Applied Mathematics and Computer Science

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2022

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Vol. 32, no. 4

601--617

EN

An integrated approach to the fault-tolerant control (FTC) of a quadcopter unmanned aerial vehicle (UAV) with incipient actuator faults is presented. The framework is comprised of a radial basis function neural network (RBFNN) fault detection and diagnosis (FDD) module and a reconfigurable flight controller (RFC) based on the extremum seeking control approach. The dynamics of a quadcopter subject to incipient actuator faults are estimated using a nonlinear identification method comprising a continuous forward algorithm (CFA) and a modified golden section search (GSS) one. A time-difference-of-arrival (TDOA) method and the post-fault system estimates are used within the FDD module to compute the fault location and fault magnitude. The impact of bi-directional uncertainty and FDD detection time on the overall FTC performance and system recovery is assessed by simulating a quadcopter UAV during a trajectory tracking mission and is found to be robust against incipient actuator faults during straight and level flight and tight turns.

7

Fault-tolerant tracking control for a non-linear twin-rotor system under ellipsoidal bounding

Kukurowski Norbert, Mrugalski Marcin, Pazera Marcin, Witczak Marcin

International Journal of Applied Mathematics and Computer Science

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2022

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Vol. 32, no. 2

171--183

EN

A novel fault-tolerant tracking control scheme based on an adaptive robust observer for non-linear systems is proposed. Additionally, it is presumed that the non-linear system may be faulty, i.e., affected by actuator and sensor faults along with the disturbances, simultaneously. Accordingly, the stability of the robust observer as well as the fault-tolerant tracking controller is achieved by using the ℋ∞ approach. Furthermore, unknown actuator and sensor faults and states are bounded by the uncertainty intervals for estimation quality assessment as well as reliable fault diagnosis. This means that narrow intervals accompany better estimation quality. Thus, to cope with the above difficulty, it is assumed that the disturbances are over-bounded by an ellipsoid. Consequently, the performance and correctness of the proposed fault-tolerant tracking control scheme are verified by using a non-linear twin-rotor aerodynamical laboratory system.

8

A multi-model based adaptive reconfiguration control scheme for an electro-hydraulic position servo system

Zhang Zhao, Yang Zhong, Liu Shuchang, Chen Shuang, Zhang Xiaokai

International Journal of Applied Mathematics and Computer Science

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2022

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Vol. 32, no. 2

185--196

EN

Reliability and safety of an electro-hydraulic position servo system (EHPSS) can be greatly reduced for potential sensor and actuator faults. This paper proposes a novel reconfiguration control (RC) scheme that combines multi-model and adaptive control to compensate for the adverse effects. Such a design includes several fixed models, one adaptive model, and one reinitialized adaptive model. Each of the models has its own independent controller that is based on a complete parametrization of the corresponding fault. A proper switching mechanism is set up to select the most appropriate controller to control the current plant. The system output can track the reference model asymptotically using the proposed method. Simulation results validate robustness and effectiveness of the proposed scheme. The main contribution is a reconfiguration control method that can handle component faults and maintain the acceptable performance of the EHPSS.

9

Health management using fault detection and fault tolerant control of multicellular converter applied in more electric aircraft system

Mahboub Mohamed Abdelbasset, Rouabah Boubakeur, Kafi Mohamed Redouane, Toubakh Houari

Diagnostyka

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2022

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Vol. 23, No. 2

art. no. 2022212

EN

The increased cost of fuel and maintenance in aircraft system lead to the concept of more electric aircraft, moreover this concept increase the use of power electronic converters in aircraft power system. Since in this application, the reliability is a crucial feature. Therefore, the use of more efficient, reliable and robust power converter with health management capability will be a big challenge. Multicellular topology of power converters has the required performance in terms of efficiency and robustness. However, the increased complexity of control and more power components (power switches and capacitors) goes along with an increase in possibility of failure in multicellular topology. Therefore, the main contribution of this paper is the use of multicellular topology advantageous with fault diagnosis and fault tolerant control in order to increase the robustness reliability. The health management using a fault detection with Fuzzy Pattern Matching (FPM) algorithm when a failure in power switches or flying capacitors of multicellular converter and a Fault Tolerant Control (FTC) with sliding mode of second parallel three cells multicellular converters. Simulation results with Matlab show the increased efficiency and the continuity of work during failure mode in aircraft power system.

10

Pitch and yaw motion control of 2 DoF helicopter subjected to faults using sliding-mode control

Raghappriya M., Kanthalakshmi S.

Archives of Control Sciences

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2022

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Vol. 32, No. 2

359--381

EN

This paper presents a fault-tolerant control scheme for a 2 DOF helicopter. The 2 DOF helicopter is a higher-order multi-input multi-output system featuring non-linearity, cross-coupling, and unstable behaviour. The impact of sensor, actuator, and component faults on such highly complex systems is enormous. This work employs sliding mode control, which is based on reaching and super-twisting laws, to handle the problem of fault control. Simulation tests are carried out to show the effectiveness of the algorithms. Various performance metrics are analyzed and the results show SMC based on super-twisting law provides better control with less chattering. The stability of the closed-loop system is mathematically assured, in the presence of faults, which is a key contribution of this research.

11

Enhanced Reliability for Winding Machine via New Fault Tolerant Control Based on RST-Backstepping Controller

Haouari Fouad, Messekher Salaheddine, Bali Noureddine, Tadjine Mohamed, Boucherit Mohamed Seghir

Power Electronics and Drives

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2021

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Vol. 6 (41)

229--241

EN

Due to the external disturbances, model uncertainties, strong coupling, and occurred faults, the winding machine presents a great control challenge. In order to deal with these problems, this paper presents the formulation of a novel scheme of fault tolerant control (FTC) for three-motor web-winding systems; it is concerned with the nonlinear robust backstepping control based on the combination of RST and backstepping controllers where the process is modelled by a nonlinear model. The main contribution of the paper is that the approach developed here summarises the performance of RST and backstepping controllers in order to design a robust controller capable of eliminating external disturbances and sensor faults affecting the system. The stability of the whole system is proven using the Lyapunov theory. Finally, analysis in comparison with the conventional backstepping controller and simulations in the MATLAB environment are accomplished to confirm the efficiency of the proposed method.

12

Rotor Resistance Estimator based on Virtual Current Sensor Algorithm for Induction Motor Drives

Adamczyk Michał

Power Electronics and Drives

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2020

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Vol. 5 (40)

143--156

EN

In this article, model reference adaptive system (MRAS)-based estimator of a rotor resistance of an induction motor (IM) is presented. In contrast to the solutions known from the literature, the reference model of this estimator uses the measured values of the phase current and the adaptive part is a virtual current sensor. The article presents an accurate description of the algorithm taking into account the discrete equations for possible practical implementation in the microprocessor system. In the first step, the impact of motor parameters to stator current estimation quality in the adaptive model was checked. Subsequently, simulation tests of the proposed rotor resistance estimator were carried out for the field-oriented control of the induction motor drive system with a model of an induction motor with fixed parameters and an induction motor with a changing main inductance according to a magnetisation curve. The analysis of the estimator’s work showed its high efficiency and insensitivity to changes in the IM main inductance.

13

Fault tolerant multicontrollers for nonlinear systems: A real validation on a chemical process

Mejdi Sondess, Messaoud Anis, Ben Abdennour Ridha

International Journal of Applied Mathematics and Computer Science

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2020

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Vol. 30, no. 1

61--74

EN

An active sensor fault tolerant controller for nonlinear systems represented by a decoupled multimodel is proposed. Active fault tolerant control requires accurate fault estimation. Thus, to estimate both state variables and sensor faults, a discrete unknown input multiobserver, based on an augmented state multimodel, is designed. The multiobserver gains are computed by solving linear matrix inequalities with equality constraints. A multicontrol strategy is proposed for the compensation of the sensor fault and recovering the desired performances. This strategy integrates a bank of controllers, corresponding to a set of partial models, to generate a set of control laws compensating the fault effect. Then, a switching strategy between the generated local control laws is established in order to apply the most suitable control law that tolerates the fault and maintains good closed loop performances. The effectiveness of the proposed strategy is proven through a numerical example and also through a real time application on a chemical reactor. The obtained results confirm satisfactory closed loop performance in terms of trajectory tracking and fault tolerance.

14

Fault tolerant control of wind turbine via identified fuzzy models prototypes

Djoudi Habib Chaouki Ben, Hafaifa Ahmed, Djoudi Dalila, Guemana Mouloud

Diagnostyka

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2020

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Vol. 21, No. 3

3--13

EN

The main purpose of this study is the comparison of two control strategies of wind turbine 4.8 MW, using fuzzy control and proportional integral control, taking into account eight kinds of faults that can occur in a wind turbine model. A technique based on fault diagnosis has been used to detect and isolate faults actuators and sensors in this system, it's about an observer applied to the benchmark model. The obtained results are presented to validate the effectiveness of this diagnostic method and present the results of the proposed control strategies.

15

Sensorless field oriented control for five-phase induction motors with third harmonic injection and fault insensitive feature

Wilczyński Filip, Strankowski P., Guziński J., Morawiec M., Lewicki A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2019

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Vol. 67, nr 2

253--262

EN

The paper presents a solution for sensorless field oriented control (FOC) system for five-phase induction motors with improved rotor flux pattern. In order to obtain the advantages of a third harmonic injection with a quasi-trapezoidal flux shape, two vector models, α1–β1 and α3–β3, were transformed into d1– q1, d3– q3 rotating frames, which correlate to the 1st and 3rd harmonic plane respectively. A linearization approach of the dual machine model in d – q coordinate frames is proposed by introducing a new additional variable “x” which is proportional to the electromagnetic torque. By applying the static feedback control law, a dual mathematical model of the five-phase induction motor was linearized to synthesize a control system in which the electromagnetic torque and the rotor flux can be independently controlled. The results shows the air gap flux shape in steady as well transient states under various load conditions. Moreover, the implemented control structure acquires fault tolerant properties and leads to possible emergency running with limited operation capabilities. The fault-tolerant capability of the analyzed machine was guaranteed by a special implemented control system with a dedicated speed observer, which is insensitive to open-phase fault situation. The experimental tests have been performed with single and double-open stator phase fault. A torque measurement was implemented to present the mechanical characteristics under healthy and faulty conditions of the drive system.

16

Robust multiple sensor fault-tolerant control for dynamic non-linear systems: Application to the aerodynamical twin-rotor system

Pazera M., Buciakowski M., Witczak M.

International Journal of Applied Mathematics and Computer Science

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2018

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Vol. 28, no. 2

297--308

EN

The paper deals with the problem of designing sensor-fault tolerant control for a class of non-linear systems. The scheme is composed of a robust state and fault estimator as well as a controller. The estimator aims at recovering the real system state irrespective of sensor faults. Subsequently, the fault-free state is used for control purposes. Also, the robust sensor fault estimator is developed in a such a way that a level of disturbances attenuation can be reached pertaining to the fault estimation error. Fault-tolerant control is designed using similar criteria. Moreover, a separation principle is proposed, which makes it possible to design the fault estimator and control separately. The final part of the paper is devoted to the comprehensive experimental study related to the application of the proposed approach to a non-linear twin-rotor system, which clearly exhibits the performance of the new strategy.

17

Adaptive fault-tolerant position control of a hexacopter subject to an unknown motor failure

Falconí G. P., Angelov J., Holzapfel F.

International Journal of Applied Mathematics and Computer Science

|

2018

|

Vol. 28, no. 2

309--321

EN

This paper presents a fault tolerant position tracking controller for a hexarotor system. The proposed controller has a cascaded structure composed of a position and an attitude control loop. The nominal controller is augmented by an adaptive control allocation which compensates for faults and failures within the propulsion system without reconfiguration of the controller. Simultaneously, it is able to implement a degraded control strategy which prioritizes specific control directions in the case of extreme degradation. The main contribution is a controller that is a step closer to application scenarios by including outdoor GPS-based flight tests, onboard computation and the handling of unknown degradation and failure of any rotor.

18

Active fault tolerance control of a wind turbine system using an unknown input observer with an actuator fault

Li S., Wang H., Aitouche A., Tian Y., Christov N.

International Journal of Applied Mathematics and Computer Science

|

2018

|

Vol. 28, no. 1

69--81

EN

This paper proposes a fault tolerant control scheme based on an unknown input observer for a wind turbine system subject to an actuator fault and disturbance. Firstly, an unknown input observer for state estimation and fault detection using a linear parameter varying model is developed. By solving linear matrix inequalities (LMIs) and linear matrix equalities (LMEs), the gains of the unknown input observer are obtained. The convergence of the unknown input observer is also analysed with Lyapunov theory. Secondly, using fault estimation, an active fault tolerant controller is applied to a wind turbine system. Finally, a simulation of a wind turbine benchmark with an actuator fault is tested for the proposed method. The simulation results indicate that the proposed FTC scheme is efficient.

19

Robust MPC for actuator-fault tolerance using set-based passive fault detection and active fault isolation

Xu F., Puig V., Ocampo-Martinez C., Olaru S., Niculescu S. I.

International Journal of Applied Mathematics and Computer Science

|

2017

|

Vol. 27, no. 1

43--61

EN

In this paper, a fault-tolerant control (FTC) scheme is proposed for actuator faults, which is built upon tube-based model predictive control (MPC) as well as set-based fault detection and isolation (FDI). In the class of MPC techniques, tube-based MPC can effectively deal with system constraints and uncertainties with relatively low computational complexity compared with other robust MPC techniques such as min-max MPC. Set-based FDI, generally considering the worst case of uncertainties, can robustly detect and isolate actuator faults. In the proposed FTC scheme, fault detection (FD) is passive by using invariant sets, while fault isolation (FI) is active by means of MPC and tubes. The active FI method proposed in this paper is implemented by making use of the constraint-handling ability of MPC to manipulate the bounds of inputs. After the system has been detected to become faulty, the input-constraint set of the MPC controller is adjusted to actively excite the system for achieving FI guarantees on-line, where an active FI-oriented input set is designed off-line. In this way, the system can be excited in order to obtain more extra system-operating information for FI than passive FI approaches. Overall, the objective of this paper is to propose an actuator MPC scheme with as little as possible of FI conservatism and computational complexity by combining tube-based MPC and set theory within the framework of MPC, respectively. Finally, a case study is used to show the effectiveness of the proposed FTC scheme.

20

An active fault-tolerant control framework against actuator stuck failures under input saturations

Qi X., Theilliol D., He Y., Han J.

International Journal of Applied Mathematics and Computer Science

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2017

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Vol. 27, no. 4

749--761

EN

In this paper, a control framework including active fault-tolerant control (FTC) and reference redesign is developed subject to actuator stuck failures under input saturations. FTC synthesis and reference redesign approaches are proposed to guarantee post-fault system safety and reference reachability. Then, these features are analyzed under both actuator stuck failures and constraints before fault-tolerant controller switches. As the main contribution, actuator stuck failures and constraints are unified so that they can be easily considered simultaneously. By means of transforming stuck failures into actuator constraints, the post-fault system can be regarded as an equivalent system with only asymmetrical actuator constraints. Thus, methods against actuator saturations can be used to guarantee regional stability and produce the stability region. Based on this region, stuck compensation is analyzed. Specifically, an unstable open-loop system is considered, which is more challenging. Furthermore, the method is extended to a set-point tracking problem where the reachability of the original reference can be evaluated. Then, a new optimal reference will be computed for the post-fault system if the original one is unreachable. Finally, simulation examples are shown to illustrate the theoretical results.