Xuelian Yao

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.

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.

Adaptive actuator failure compensation and disturbance rejection scheme for spacecraft

An adaptive actuator failure compensation scheme is proposed for attitude tracking control of spacecraft with unknown disturbances and uncertain actuator failures. A new feature of this adaptive control scheme is the adaptation of the failure pattern parameter estimates, as well as the failure signal parameter estimates, for direct adaptive actuator failure compensation. Based on an adaptive backstepping control design, the estimates of the disturbance parameters are used to solve the disturbance rejection problem. The unknown disturbances are compensated completely with the stability of the whole closed-loop system. The scheme is not only able to accommodate uncertain actuator failures, but also robust against unknown external disturbances. Simulation results verify the desired adaptive actuator failure compensation performance.

An adaptive reconfigurable longitudinal trajectory control applied to the damaged space shuttle for approach and landing

This paper presents an adaptive reconfigurable longitudinal trajectory control system applied to the damaged Space Shuttle for un-powered approach and landing. The controller is decomposed into four feedback loops: pitch-rate, angle-of-attack, flight-path-angle and altitude loop, among which the altitude loop is in the outer most and the pitch-rate loop is in the inner most. The pitch-rate loop is based on dynamic inversion technique and the other loops are in a backstepping control scheme. The onboard models used by dynamic inversion and backstepping are linearized models at some equilibrium points, and inversion model errors are compensated by online learning neural networks. The results of high-fidelity simulation indicate that the control system can maintain desirable stability and performance properties in the presence of wing damage.

An adaptive actuator failure compensation scheme for spacecraft with unknown inertia parameters

An adaptive actuator failure compensation scheme is developed for attitude tracking control of a spacecraft with unknown inertia parameters. The proposed scheme employs a composite parameter adaptation design which incorporates an adaptive backstepping feedback control law and an adaptive feedforward actuator failure compensator and guarantees the overall closed-loop system stability and asymptotic tracking. 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. Illustrative simulation results of an application to a spacecraft model show that the desired properties are achieved in the presence of the unknown inertia matrix and uncertain actuator failures.

Tracking control of underactuated ships with uncertain actuator failures using switching control

This paper develops an actuator failure accommodation control scheme for an underactuated ship dynamic system model with uncertain actuator failures, using a switching control design. Such a design employs multiple controllers, each of which is designed for each failure pattern in the failure pattern set of interest. To stabilize the system under uncertain actuator failures, control signal selection is based on comparing the performance indices from prediction errors generated by multiple state predictors, each of which is designed for one failure pattern. Different from those problems addressed in the literature, the key feature of the underactuation problem considered in this paper is that it is unknown when and which actuator fails during system operation. Simulation results from a ship system model in the presence of uncertain actuator failures are presented to show the desired system stability and asymptotic tracking properties.

An adaptive actuator failure compensation scheme for spacecraft with momentum wheels

An adaptive actuator failure compensation scheme is developed for attitude tracking control of a spacecraft with four reaction momentum wheels, in the presence of unknown spacecraft inertia parameters, nonlinear dynamics of wheel angular momentum and uncertain actuator failures. The proposed scheme employs a composite adaptive control design which incorporates an adaptive backstepping feedback control law and an adaptive feedforward actuator failure compensator whose parameters are adaptive estimates of failure pattern and value parameters. All possible failures can be estimated based on a complete parametrization without explicit failure detection. Based on a new compensation framework, the unknown system parameters can be estimated directly and the additional disturbances introduced by the nonlinear dynamics can be compensated completely, so that the stability of the closed-loop system and asymptotic attitude tracking can be achieved despite the presence of the unknown inertia matrix and uncertain actuator failures. Illustrative simulation results are presented to verify the desired system properties.