Ruiyun Qi

Adaptive output feedback fault-tolerant control design for hypersonic flight vehicles

Abstract In this paper, an adaptive output feedback fault-tolerant controller is developed for the longitudinal dynamics of a generic hypersonic flight vehicle in the presence of parameter uncertainties, actuator faults and external disturbances. Firstly, the derivatives of the output are calculated repeatedly so that the relative degree of the system is obtained. Then feedback linearization is used to design the nominal controller. Considering the occurrence of actuator faults, a fault-tolerant controller is developed based on the nominal feedback linearization controller to accommodate the effect of actuator fault, ensure system stability and recover desirable tracking performance. Since some of the states are difficult to measure during actual hypersonic flight, the high-gain observer technique is adopted to achieve output feedback fault-tolerant control. Adaptive laws are designed for updating the controller parameters when both the plant parameters and actuator fault parameters are unknown. Closed-loop stability and output tracking performance are analyzed rigorously. Simulation results verify the effectiveness of the proposed adaptive fault-tolerant control scheme.

Adaptive backstepping control for a hypersonic vehicle with uncertain parameters and actuator faults

For a hypersonic vehicle with redundant elevators, an adaptive backstepping fault-tolerant control scheme is designed for its longitudinal motion model. In the backstepping design, the dynamic surface control strategy is adopted to eliminate the explosion of complexity in calculating the derivatives of virtual control inputs by introducing two first-order filters. An appropriate controller structure is proposed and the matching conditions are derived for adaptive fault compensation for the vehicle with redundant elevators subject to uncertain actuator faults. The adaptation laws are designed to update parameter estimates to implement the adaptive controller. The closed-loop stability under the proposed adaptive actuator fault compensation scheme is analyzed. Both analytical and simulation results are given to verify the effectiveness of the design and demonstrate the desired performance for altitude and velocity control.

Adaptive control schemes for discrete-time T-S fuzzy systems with unknown parameters and actuator failures

This paper develops a new solution framework with detailed system modeling, and control design, analysis and evaluation, for adaptive control of discrete-time input-output multiple-delay T-S fuzzy systems with unknown parameters and uncertain actuator failures. A multiple-delay prediction fuzzy system model is derived and its minimum phase property is clarified. Based on a model-based approach, the design and analysis are presented for an adaptive control scheme for multiple-delay T-S fuzzy systems, and an adaptive actuator failure compensation for systems with redundant actuators subject to uncertain failures, for which new system parametrizations and controller structures are developed. Illustrative examples and simulation results are presented to demonstrate the studied new concepts and to verify the desired performance of the new types of adaptive fuzzy control systems.

Adaptive control of discrete-time state-space T--S fuzzy systems with general relative degree

This paper develops a new solution framework for adaptive control of general discrete-time state-space T-S fuzzy systems with a relative degree ρ (1 ≤ ρ ≤ n). A new procedure is proposed to construct a global T-S fuzzy system model from local state-space models in non-canonical form, which has an explicit relative degree structure and a specific input-output signal causality relationship in the sense that it does not include any future values of fuzzy membership functions. An adaptive feedback control scheme is designed based on the global T-S fuzzy model, to ensure desired stability and tracking. As an illustrative example, a T-S fuzzy system is constructed based on the linearized local models of a transport airplane. Simulation results have demonstrated the developed new concepts and verified the desired performance of the new type of adaptive fuzzy control systems.

An adaptive actuator failure compensation scheme for a class of nonlinear MIMO systems

Abstract This paper develops an adaptive actuator failure compensation scheme for control of a class of nonlinear multi-input–multi-output systems with redundant actuators subject to uncertain failures. The design method is to estimate the failure pattern parameters and the failure signal parameters first, and then use the parameter estimates to construct the adaptive failure compensation controller, the control law calculation is done simultaneously with parameter estimation without explicit failure detection. Closed-loop signal boundedness and asymptotic output tracking, despite the actuator failure uncertainties, are ensured analytically and verified by simulation results from its application to attitude control of a near space vehicle dynamic model.

A discrete-time parameter estimation based adaptive actuator failure compensation control scheme

This paper studies discrete-time adaptive failure compensation control of systems with uncertain actuator failures, using an indirect adaptive control method. A discrete time model of a continuous-time linear system with actuator failures is derived and its key features are clarified. A new discrete-time adaptive actuator failure compensation control scheme is developed, which consists of a total parametrization of the system with parameter and failure uncertainties, a stable adaptive parameter estimation algorithm, and an on-line design procedure for feedback control. This work represents a new design of direct adaptive compensation of uncertain actuator failures, using an indirect adaptive control method. Such an adaptive design ensures desired closed-loop system stability and asymptotic tracking properties despite uncertain actuator failures. Simulation results are presented to show the desired adaptive actuator failure compensation performance.

An adaptive actuator failure compensation scheme for an attitude dynamic model of near space vehicles

An adaptive actuator failure compensation scheme is developed for control of a class of nonlinear multi-input multioutput systems with redundant actuators subject to uncertain failures. A new feature of this adaptive control scheme is the adaptation of the failure pattern parameter estimates, together with that of the failure signal parameter estimates, for direct adaptive actuator failure compensation, without explicit failure detection. It is shown that such an adaptive design is able to ensure the desired closed-loop stability and asymptotic output tracking despite the actuator failure uncertainties. Simulation results from its application to attitude control of a near space vehicle dynamic model are presented to verify the desired system performance with adaptive actuator failure compensation.

A Multiple-Model Based Adaptive Actuator Failure Compensation Scheme for Control of Near-Space Vehicles*

Abstract This paper presents a new adaptive actuator failure compensation control scheme for nonlinear systems motivated from a near space vehicle control application, using a multiple-model failure estimation and control approach. Such a design employs multiple controllers, each of which is designed for each failure pattern in the failure pattern set of interest and is constructed with parameters from adaptive estimates of the failure parameters of a specific actuator failure. Each estimator is based on a complete parametrization of the corresponding actuator failure. A switching mechanism is set up, based on finding the minimal performance cost index from the estimation errors, to select the most appropriate controller to generate the current control signal. Simulation results from the attitude control of a near space vehicle dynamic model in the presence of uncertain actuator failures are presented to show the desired adaptive actuator failure compensation performance.

Adaptive actuator failure compensation design for spacecraft attitude control

An adaptive actuator failure and disturbance compensation scheme is developed for attitude tracking control of spacecraft. The proposed scheme consists of a composite parameter adaptation design that incorporates an adaptive backstepping feedback control law and an adaptive feedforward actuator failure compensator; it can guarantee the overall closed-loop system stability and asymptotic tracking. Illustrative simulation results of an application to a spacecraft model show that the designed actuator failure compensation controller ensures system stability and tracking performance.

An adaptive state tracking control scheme for T–S fuzzy models in non-canonical form and with uncertain parameters☆

Abstract This paper develops a novel adaptive state tracking control scheme based on Takagi–Sugeno (T–S) fuzzy models with unknown parameters. The proposed method can deal with T–S models in a non-canonical form and allows the number of inputs to be less than state variables, which is more practical and has wider applications. The needed matching conditions for state tracking are relaxed by using a T–S fuzzy reference model to generate desired state reference signals. A new fuzzy estimator model is constructed whose states are compared with those of the T–S fuzzy model to generate the estimator state error which is used for the parameter adaptive law. Based on the Lyapunov stability theory, it has been proven that all the signals in the closed-loop system are bounded and the asymptotic state tracking can be achieved. The effectiveness of the proposed scheme is demonstrated through a magnetic suspension system and a transport airplane model.