Fault tolerant sliding mode control for T-S fuzzy stochastic time-delay system via a novel sliding mode observer approach

In this paper, a fault estimation and fault-tolerant control problem for a class of T-S fuzzy stochastic time-delay systems with actuator and sensor faults is investigated. A novel sliding mode observer is proposed, which can simultaneously estimate the system states, actuator and sensor faults with good accuracy. Based on the state and actuator fault estimation, a new sliding mode control scheme is developed, which can effectively eliminate the influence of actuator fault. Sufficient conditions for the existence of the proposed observer and fault-tolerant sliding mode controller are provided in terms of linear matrix inequality, and moreover, the reachability of the sliding mode surface can be guaranteed under the proposed control scheme. The propose sliding mode observer and fault-tolerant sliding mode controller can overcome the restrictive assumption that the input matrix of all local modes is the same. Finally, a numerical example is provided to verify the effectiveness of the proposed sliding mode observer and fault-tolerant sliding mode control technique.     

Fault-tolerant Control for Linear System Under Sensor Saturation Constraint

An observer-based fault-tolerant control method is proposed for a linear system with sensor saturation constraint. Considering the linear system with simultaneous actuator faults and sensor faults, the sensor saturation would bring the output measurement error of the system, which would result in the estimation performance degradation. Firstly, the intermediate estimator is modified to estimate the system states and fault signals at the simultaneous time, and the fault-tolerant controller is designed based on the estimation to compensate the effect of actuator faults effectively. Through Lyapunov stability analysis, the sufficient conditions are obtained to ensure the states of closed-loop system to be uniformly ultimately bounded. The effect of sensor saturation error can be suppressed by adjusting some specified parameters directly without introducing any performance index. Finally, the effectiveness and superiority of the proposed method are verified by a simulation example.

     

Reliable H∞ control for nonlinear discrete-time systems with multiple intermittent faults in sensors or actuators

This study proposes a fault-tolerant control method for stochastic systems with multiple intermittent faults (IFs) and nonlinear disturbances, and both sensor and actuator faults are considered. The occurrence and disappearance of IFs are governed by Markov chain, and its transition probabilities are partly known. Hence, the faulty system can be described by a Markovian jump system (MJS). In order to ensure that the MJS is stochastically stable and satisfies H_∞ performance index, mode-dependent output feedback controllers are modelled using linear matrix inequalities. Numerous sufficient conditions for stochastic stability are obtained on the basis of Lyapunov stability theory. Finally, the effectiveness of the developed method is evaluated on the three-tank system.     

推力矢量飞机鲁棒故障检测与辨识和 指令滤波容错控制系统设计

针对推力矢量飞机(TVA)在超机动飞行中的舵面故障、执行器故障、参数摄动和外界干扰等问题,提出了一种鲁棒故障检测与辨识和指令滤波容错控制(RFDI–CFFTC)系统设计方法.首先针对TVA故障模型提出了一种基于多观测器的RFDI机制,通过引入自适应律和观测器来补偿参数摄动和外界干扰的影响,实现对舵面故障和执行器故障的准确检测与辨识,同时准确估计故障程度;然后在RFDI的基础上,设计了CFFTC容错控制律,实现包容舵面故障、执行器故障、参数摄动和外界干扰的TVA容错控制,同时改善了传统反步法中的“微分爆炸”问题;最后对RFDI–CFFTC系统的稳定性进行了证明.MATLAB/Simulink仿真验证了本文方法的有效性.     

预设跟踪性能下车辆队列执行器故障主动容错控制

研究预设跟踪性能下的车辆队列执行器故障主动容错控制问题.考虑执行器部分失效和偏移故障情形,设计Luenberger观测器和自适应残差阈值以实现执行器故障检测.在此基础上,为了确保执行器故障下的车辆队列暂态和稳态性能,在预设跟踪性能框架下,设计基于反步法的主动容错控制算法,在满足预设性能的前提下,实现车辆队列跟踪误差有界,且车辆间距满足安全性和紧凑性约束.仿真结果验证了所提出主动容错控制算法的有效性.     

Fault-tolerant control systems design via subdivision of parameter region

This paper presents a linear matrix inequality （LMI） approach to solve the fault-tolerant control （FTC） problem of actuator faults. The range of actuator faults is considered as a parameter region and subdivided into several subregions to achieve a certain desired performance specification. Based on the integral quadratic constraint （IQC） approach, a passive fault-tolerant controller for the whole fault region and multiple fault-tolerant controllers for each fault subregion are designed for guaranteeing stability and improving performance of the FTC system, respectively. According to the estimation of parameters by FDI process, the corresponding subregion controller is chosen for the stability and optimal performance of closed-loop systems when the fault occurs. The case of incorrect estimation is also considered by comparing the performance index between the switched controller and the passive fault-tolerant controller. The proposed design technique is finally evaluated in the light of a simulation example.     

Adaptive fault-tolerant control of linear systems with actuator saturation and L_2-disturbances

This paper studies the problem of designing adaptive fault-tolerant H-infinity controllers for linear timeinvariant systems with actuator saturation.The disturbance tolerance ability of the closed-loop system is measured by an optimal index.The notion of an adaptive H-infinity performance index is proposed to describe the disturbance attenuation performances of closed-loop systems.New methods for designing indirect adaptive fault-tolerant controllers via state feedback are presented for actuator fault compe...     

Fault estimation and controller compensation in Lure systems by LPV-embedding

Previous works have considered the use of set invariance theory for fault detection and isolation in nonlinear Lure systems. This paper extends those results and proposes a new actuator fault-tolerant control approach. The fault-tolerant control scheme is designed based on linear parameter-varying (LPV) models of Lure systems. The actuator fault situation is diagnosed by an invariant set-based fault detection and isolation algorithm. Faults are compensated by adapting the controller gain based on estimates of the fault magnitude. Conditions for correct fault detection and isolation, and closed-loop stability are derived. The proposed fault-tolerant control scheme is compared with a linearised model approach and the performance of both, LPV-embedding and linearised, approaches are analysed for scalar and second-order systems. An example of a chaotic Chua circuit is also provided to illustrate the proposed fault-tolerant control scheme in higher-order systems.     

Bumpless switching control for switched systems with partial actuator failures

This study is concerned with the bumpless transfer problem for switched systems with partial actuator failures, in order to obtain smooth system performance output transition. Taking into account that the system requires a controller switching from current sub-controller to a fault-tolerant sub-controller after actuator fault. And bumpless transfer for control input cannot be traditionally designed when the actuator fault occurs, while performance smoothing can be considered and it is actually the ultimate goal of bumpless transfer. Specifically, the actuator fault model is firstly established and partial actuator fault is considered. Then, the system performance output signal is deemed as the main design variable of bumpless transfer, and closed-loop control systems both previous and after controller switching are constructed. Moreover, by using model matching thought and the adaptive sliding mode control technique, a bumpless transfer compensator design strategy is given to drive the performance output variable (after controller switching) to track the one of reference model. At last, simulation results of numeric and application examples demonstrate the effectiveness of the proposed bumpless transfer strategy.