Jinxing Lin

Active fault tolerant control design for reusable launch vehicle using adaptive sliding mode technique

Abstract In this paper, the problem of active fault tolerant control for a reusable launch vehicle (RLV) with actuator fault using both adaptive and sliding mode techniques is investigated. Firstly, the kinematic equations and dynamic equations of RLV are given, which represent the characteristics of RLV in reentry flight phase. For the dynamic model of RLV in faulty case, a fault detection scheme is proposed by designing a nonlinear fault detection observer. Then, an active fault tolerant tracking strategy for RLV attitude control systems is presented by making use of both adaptive control and sliding mode control techniques, which can guarantee the asymptotic output tracking of the closed-loop attitude control systems in spite of actuator fault. Finally, simulation results are given to demonstrate the effectiveness of the developed fault tolerant control scheme.

Stabilization of discrete-time switched singular time-delay systems under asynchronous switching ☆

Abstract This paper is concerned with the problem of state feedback stabilization of a class of discrete-time switched singular systems with time-varying state delay under asynchronous switching. The asynchronous switching considered here means that the switching instants of the candidate controllers lag behind those of the subsystems. The concept of mismatched control rate is introduced. By using the multiple Lyapunov function approach and the average dwell time technique, a sufficient condition for the existence of a class of stabilizing switching laws is first derived to guarantee the closed-loop system to be regular, causal and exponentially stable in the presence of asynchronous switching. The stabilizing switching laws are characterized by a upper bound on the mismatched control rate and a lower bound on the average dwell time. Then, the corresponding solvability condition for a set of mode-dependent state feedback controllers is established by using the linear matrix inequality (LMI) technique. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed method.

Control discrete-time switched singular systems with state delays under asynchronous switching

This article is concerned with the problem of state feedback control for a class of discrete-time switched singular systems with time-varying state delays under asynchronous switching. The asynchronous switching considered here means that the switching instants of the candidate controllers lag behind those of the system modes. The concept of mismatched control rate is introduced. By using the multiple Lyapunov function approach and the average dwell time technique, a sufficient condition for the existence a stabilising switching law is first derived to guarantee the regularity, causality and exponential stability of the closed-loop system in the presence of asynchronous switching. The stabilising switching law is characterised by a upper bound on the mismatched control rate and a lower bound on the average dwell time. Then, the corresponding solvability condition for a set of mode-dependent state feedback controllers is established by using the linear matrix inequality (LMI) technique. Finally, a numerical example is provided to illustrate the effectiveness of the proposed method.

Fractional-order PD control at Hopf bifurcations in delayed fractional-order small-world networks

Abstract Bifurcation and control of fractional-order systems are still an outstanding problem. In this paper, a novel delayed fractional-order model of small-world networks is introduced and several topics related to the dynamics and control of such a network are investigated, such as the stability, Hopf bifurcations, and bifurcation control. The nonlinear interactive strength is chosen as the bifurcation parameter to analyze the impact of the interactive strength parameter on the dynamics of the fractional-order small-world network model. Firstly, the stability domain of the equilibrium is completely characterized with respect to network parameters, delays and orders, and some explicit conditions for the existence of Hopf bifurcations are established for the delayed fractional-order model. Then, a fractional-order Proportional-Derivative (PD) feedback controller is first put forward to successfully control the Hopf bifurcation which inherently happens due to the change of the interactive parameter. It is demonstrated that the onset of Hopf bifurcations can be delayed or advanced via the proposed fractional-order PD controller by setting proper control parameters. Meanwhile, the conditions of the stability and Hopf bifurcations are obtained for the controlled fractional-order small-world network model. Finally, illustrative examples are provided to justify the validity of the control strategy in controlling the Hopf bifurcation generated from the delayed fractional-order small-world network model.

Fault tolerant attitude control design for rigid satellite using sliding mode observer technique

In this paper, the problem of fault tolerant attitude control against unknown actuator faults is investigated for the rigid satellite attitude dynamics by using sliding mode observer technique. Firstly, the satellites dynamic equations and kinematic equations are given to describe the attitude systems of rigid satellite. Then the actuator fault model is introduced to represents the loss of effectiveness fault and stuck fault. To obtain the estimation value of the effects of unknown actuator fault, a nonlinear sliding mode observer is developed and an adaptive fault estimation law is also developed. Based on the estimated fault information, an active fault tolerant attitude controller is designed for the attitude systems of rigid satellite. Meanwhile, the stability of closed-loop attitude control systems is analyzed by using Lyapunov approach. Finally, simulation results are given to demonstrate the effectiveness of the developed fault tolerant control scheme.

Active fault tolerant control design approach for the flexible spacecraft with sensor faults

Abstract In this paper, the problem of active fault tolerant control (FTC) is studied for a class of flexible spacecraft attitude systems with Lipschitz nonlinearity and sensor fault. Firstly, a functional observer is designed for the attitude systems of flexible spacecraft in order to detect the time of unknown sensor fault occurred. Next, the sensor fault estimation is performed by filtering the output estimation error, as usually done in the residual generation framework. Then, a dynamic output feedback-based FTC approach is proposed to the flexible spacecraft in sensor faulty case, it not only attenuates flexible appendage disturbance with a given level γ, but also tolerates the effect of unknown sensor fault. Finally, the effectiveness of the proposed FTC method is demonstrated in the attitude systems of flexible spacecraft subject to a time-varying sensor fault.

Active fault-tolerant control approach design for rigid spacecraft with multiple actuator faults

In this study, the active fault-tolerant control problem is investigated for a rigid spacecraft in the presence of inertia uncertainty, external disturbance, multiple actuator faults and actuator saturation. The attitude system model of spacecraft and actuator fault model are first given. A sliding mode–based fault detection observer and a radial basis function neural networks–based fault estimation observer are designed to detect the time of actuator fault occurred and estimate the amplitude of unknown fault, respectively. On that basis, an active fault-tolerant control scheme is proposed to accommodate the effects of multiple actuator faults, and it guarantees that the state trajectory of attitude systems without actuator saturation converges to a neighborhood of the origin in finite time. Another active fault-tolerant control scheme is further proposed in actuator saturation constraint case; it ensures that all the closed-loop signals are finite time convergence. Finally, simulation results are given to illustrate the effectiveness of the proposed fault-tolerant control approach.

Fault-tolerant synchronization of complex dynamical networks with actuator faults

This paper presents the fault-tolerant synchronization controller design for a class of complex dynamical networks (CDNs) in the presence of actuator being partial faulting. By using the prior knowledge of the actuator faults, the complex network with actuator faults is described as a complex network with parameter uncertainties. Furthermore, a fault tolerant synchronization criterion in the form of linear matrix inequality is proposed on the basis of the Lyapunov stability theorem and Schur complement lemma. Finally, a numerical simulation is carried out to demonstrate the effectiveness of the proposed fault-tolerant synchronization controller.

Adaptive sliding mode observer based FTC method design for rigid satellite against actuator faults

In this paper, an adaptive sliding mode observer based fault tolerant control (FTC) design method is proposed for the rigid satellite attitude control systems in actuator multiple fault case. The rigid satellite attitude control systems can be described by the dynamic equations and kinematic equations. The actuator fault model is given to represents the bias fault and loss of effectiveness fault. Then a novel nonlinear sliding mode observer is designed in order to get the estimation value of the effects of unknown actuator faults. An fault tolerant attitude controller is further designed for the rigid satellite attitude systems by utilizing the estimated fault information and backstepping control scheme. Meanwhile, the stability of closed-loop attitude control systems is analyzed by using Lyapunov appraoch. Finally, simulation results are given to demonstrate the effectiveness of the developed FTC scheme.

Active FTC approach design for a class of nonlinear flight control systems with actuator faults

In this paper, an active fault tolerant controller is designed for a class of nonlinear flight control systems with bounded external disturbances and unknown actuator effectiveness loss faults. Firstly, the nonlinear flight control system models of an aircraft are given. When some actuators occur the unknown loss of effectiveness faults, the faulty flight control systems is further established. To obtain the accurately fault estimated value, an adaptive fault estimation observer is designed for the faulty flight control systems. Then, an active fault tolerant controller design approach is proposed by using terminal sliding mode technique and the obtained estimated value of unknown actuator fault, which could asymptotically accommodate the effects of actuator faults and guarantees the stability of the closed-loop flight control systems in the case of actuator loss of effectiveness faults. Finally, these results in simulation indicate the efficiency of our presented fault tolerant control (FTC) scheme.