@article{wu_cai_2013, title={Switching fault-tolerant control of a flexible air-breathing hypersonic vehicle}, volume={227}, ISSN={["2041-3041"]}, DOI={10.1177/0959651812453914}, abstractNote={ In this paper, we will apply a switching fault-tolerant control approach to an air-breathing hypersonic vehicle subject to time-varying actuator and sensor faults. The faults under consideration include loss of effectiveness of the actuators and sensors. Possible fault scenarios are categorized into different fault cases based on the fault type and its location. For each case, a parameter-dependent (or constant gain) fault-tolerant control controller is designed to stabilize the faulty system with an optimal controlled performance. The synthesis condition of each local fault-tolerant control law is formulated in terms of linear matrix inequalities. To achieve both local optimal performance and switching stability, Youla parameterization of each individual local fault-tolerant control controller is performed and the result is applied to the closed-loop system. The quadratic stability of a fast switching closed-loop system is guaranteed by a common Lyapunov function. Simulation results based on the non-linear flexible hypersonic vehicle model and fault-tolerant linear-parameter-varying controllers are presented and the reults of these studies demonstrate the effectiveness of the proposed switching fault-tolerant control approach for application to a hypersonic vehicle. }, number={I1}, journal={PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART I-JOURNAL OF SYSTEMS AND CONTROL ENGINEERING}, author={Wu, Fen and Cai, Xuejing}, year={2013}, month={Jan}, pages={24–38} }
 @article{cai_wu_2011, title={Multiobjective fault detection and isolation for flexible air-breathing hypersonic vehicle}, volume={22}, ISSN={["1004-4132"]}, DOI={10.3969/j.issn.1004-4132.2011.01.006}, abstractNote={An application of the multiobjective fault detection and isolation (FDI) approach to an air-breathing hypersonic vehicle (HSV) longitudinal dynamics subject to disturbances is presented. Maintaining sustainable and safe flight of HSV is a challenging task due to its strong coupling effects, variable operating condi- tions and possible failures of system components. A common type of system faults for aircraft including HSV is the loss of effective- ness of its actuators and sensors. To detect and isolate multiple actuator/sensor failures, a faulty linear parameter-varying (LPV) model of HSV is derived by converting actuator/system compo- nent faults into equivalent sensor faults. Then a bank of LPV FDI observers is designed to track individual fault with minimum error and suppress the effects of disturbances and other fault signals. The simulation results based on the nonlinear flexible HSV model and a nominal LPV controller demonstrate the effectiveness of the fault estimation technique for HSV.}, number={1}, journal={JOURNAL OF SYSTEMS ENGINEERING AND ELECTRONICS}, author={Cai, Xuejing and Wu, Fen}, year={2011}, month={Feb}, pages={52–62} }
 @article{cai_wu_2010, title={Robust fault detection and isolation for parameter-dependent LFT systems}, volume={20}, ISSN={["1099-1239"]}, DOI={10.1002/rnc.1468}, abstractNote={Abstract}, number={7}, journal={INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL}, author={Cai, Xuejing and Wu, Fen}, year={2010}, month={May}, pages={764–776} }
 @article{cai_wu_2010, title={Robust parameter-dependent fault-tolerant control for actuator and sensor faults}, volume={83}, ISSN={["1366-5820"]}, DOI={10.1080/00207179.2010.481024}, abstractNote={In this article, we study a robust fault-tolerant control (FTC) problem for linear systems subject to time-varying actuator and sensor faults. The faults under consideration are loss of effectiveness in actuators and sensors. Based on the estimated faults from a fault detection and isolation scheme, robust parameter-dependent FTC will be designed to stabilise the faulty system under all possible fault scenarios. The synthesis condition of such an FTC control law will be formulated in terms of linear matrix inequalities (LMIs) and can be solved efficiently by semi-definite programming. The proposed FTC approach will be demonstrated on a simple faulty system with different fault levels and fault estimation error bounds.}, number={7}, journal={INTERNATIONAL JOURNAL OF CONTROL}, author={Cai, Xuejing and Wu, Fen}, year={2010}, pages={1475–1484} }
 @inproceedings{cai_wu_2009, title={A Robust fault tolerant control approach for LTI systems with actuator and sensor faults}, DOI={10.1109/ccdc.2009.5191903}, abstractNote={In this paper, we study a robust fault-tolerant control (FTC) problem for linear systems with time varying actuator and sensor faults and propose an parameter-dependent solution by using L2 gain optimization techniques. Using estimated faults from a fault detection and isolation (FDI) scheme, parameter-dependent robust FTC gain will be scheduled by fault magnitude to stabilize and optimize the faulty system under all possible fault scenarios. The synthesis condition of such a FTC control law will be formulated as linear matrix inequalities (LMIs) and can be solved efficiently by semi-definite programming techniques. A numerical example is used to demonstrate the proposed fault-tolerant control approach for a simple faulty systems with different fault levels and fault estimation error bounds.}, booktitle={CCDC 2009: 21st Chinese Control and Decision Conference, vols 1-6, Proceedings}, author={Cai, X. J. and Wu, F.}, year={2009}, pages={890–895} }