Control For Near Space Vehicles Research Articles

Adaptive Robust Tracking Control for Near Space Vehicles with Multi-Source Disturbances and Input–Output Constraints

In this paper, considering the simultaneous influence of multi-source disturbances, system modeling uncertainties and input–output constraints, an adaptive robust attitude tracking control scheme is proposed for near space vehicles (NSVs) which is expressed as a stochastic nonlinear system. A multi-dimensional Taylor polynomial network (MTPN) is utilized to handle the system uncertainties, and the nonlinear disturbance observer (NDO) based on MTPN is designed to estimate the external disturbances. Furthermore, by constructing the auxiliary system to tackle the input saturation and introducing the Tan-type barrier Lyapunov function (TBLF) to solve the output constraint, the constrained control strategy can be obtained. Combining with backstepping control (BC) technique and stochastic control method, an adaptive robust stochastic control scheme is developed based on NDO, MTPN, and auxiliary system, and the closed-loop system stability in the sense of probability is analyzed based on stochastic Lyapunov stability theory. Finally, numerical simulations further demonstrate the feasibility of the proposed tracking control scheme.

Adaptive sliding mode backstepping control for near space vehicles considering engine faults

A fault tolerant control methodology based adaptive sliding mode (ASM) backstepping is proposed for near space vehicle (NSV) attitude control system under engine faults. The proposed scheme combined adaptive backstepping with the sliding mode control strategy could guarantee the system's stability and track desired signals under external disturbances and engine faults. Firstly, attitude mode description and the engine faulty model are given. Secondly, a nominal control law is designed. Thirdly, a sliding mode observer is given later in order to estimate both the information of engine faults and external disturbances. An adaptive sliding mode technology based on the previous nominal control law is developed via updating faulty parameters. Finally, analyze the system's fault-tolerant performance and reliability through experiment simulation, which verifies the proposed design of fault-tolerant control can tolerate engine faults, as well as the strong robustness for external disturbance.

Adaptive neural prescribed performance tracking control for near space vehicles with input nonlinearity

In this paper, an adaptive neural tracking controller with prescribed performance is developed for near space vehicles (NSVs) with unknown parametric uncertainties, external disturbances and input nonlinearities including input saturation and dead-zone. By placing the right inverse of the dead-zone before the input nonlinearity, the serial input nonlinearity consisting of input saturation and dead-zone can be regarded as an equivalent input saturation which is solved by a common constrained control method. To guarantee the prescribed performance of the closed-loop system including the transient and steady-state performance, the constrained prescribed performance is changed into unconstrained transformation error using error transformed technology. Meanwhile, the radial basis function neural networks (RBFNNs) are adopted to tackle the system uncertainties. Then, using the auxiliary system and backstepping technology, an adaptive tracking control scheme is proposed, and all the closed-loop system signals are proved to be bounded. Finally, extensive simulations are given for the attitude motion of the NSV to illustrate the effectiveness of the developed adaptive neural control scheme.

Fault Tolerant Control for Near Space Vehicles with Input Saturation Using Disturbance Observer and Neural Networks

In this paper, a fault tolerant sliding mode control scheme is derived for near space vehicles with actuator faults, unknown external disturbance, system uncertainty and input saturation based on disturbance observer and neural networks (NNs). To deal with actuator faults, the radial basis function NNs are employed. The nonlinear disturbance observer is designed to eliminate the effect of external disturbance and system uncertainty. To tackle input saturation, the known bound of saturation is used to design the control law such that the control input is within the bounded range. Lyapunov stability analysis shows that the closed-loop system is stable and all closed-loop signals are uniformly ultimately bounded. Simulation results demonstrate the effectiveness of the developed fault tolerant control scheme, when actuator faults, unknown external disturbance, system uncertainty and input saturation appear simultaneously.

Adaptive neural observer‐based backstepping fault tolerant control for near space vehicle under control effector damage

In this study, a theoretical framework for reconfigurable flight control is developed and applied to near space vehicle (NSV) attitude dynamics. First, NSV reentry mode is described. Second, an adaptive neural network observer is proposed, which ensures asymptotic convergence of the state observer error to zero under control effector damage and uncertainty. Next, a reconfigurable command-filter backstepping controller is designed based on the adaptive neural network observer. The authors focus is on the accommodation of the control effector damage, uncertainty and resulting disturbances. It is shown that the presented new control design results in asymptotic convergence of the attitude tracking error to zero. Finally, simulation results are given to demonstrate the effectiveness and potential of the proposed fault tolerant control scheme.

Modelling and fault tolerant control for near space vehicles with vertical tail loss

This work focuses on modelling and fault tolerant algorithm design of a damaged near space vehicle. A novel radial basis function (RBF) neural network backstepping fault-tolerant control methodology is developed for attitude control system with damage, which can make system stable and accurately track the desired signals in the presence of vertical tail loss. First, the changing aerodynamic parameters caused by vertical tail loss are used to model damaged attitude dynamics. Second, in view of the established damaged model, a nominal backstepping controller is designed. Then a RBF neural network technology is designed to update the related parameters, which can compensate effects caused by damage and make the system still stable and track the desired signals. Finally, simulation results are provided to show the effectiveness of the proposed RBF neural network backstepping fault-tolerant control scheme.

Active fault‐tolerant control for near space vehicles based on reference model adaptive sliding mode scheme

SUMMARYIn this paper, an adaptive sliding mode (ASM) scheme is proposed for fault identification and fault‐tolerant control of near space vehicles (NSVs). First, the attitude dynamic model is introduced, and a baseline controller based on reference sliding mode scheme is designed in the case of no faults. Then fault parameterizations with actuator dynamics is presented for several classes of faults: lock‐in‐place, float, hard‐over, and loss of effectiveness. On the basis of adaptive observer design, fault parameters can be accurately estimated on‐line. Furthermore, an ASM fault‐tolerant controller is designed for both cases of actuator dynamic faults and control effector damage. Finally, simulation experiments show that the proposed ASM scheme is able to quickly and accurately identify faults and reconfigure the controller, resulting in excellent overall system performance. Copyright © 2012 John Wiley & Sons, Ltd.

Sliding Mode Control for NSVs with Input Constraint Using Neural Network and Disturbance Observer

The sliding mode control (SMC) scheme is proposed for near space vehicles (NSVs) with strong nonlinearity, high coupling, parameter uncertainty, and unknown time-varying disturbance based on radial basis function neural networks (RBFNNs) and the nonlinear disturbance observer (NDO). Considering saturation characteristic of rudders, RBFNNs are constructed as a compensator to overcome the saturation nonlinearity. The stability of the closed-loop system is proved, and the tracking error as well as the disturbance observer error can converge to the origin through the Lyapunov analysis. Simulation results are presented to demonstrate the effectiveness of the proposed flight control scheme.

DSC‐backstepping based robust adaptive LS‐SVM control for near space vehicle's reentry attitude

PurposeThe purpose of this paper is to propose a robust control scheme for near space vehicle's (NSV's) reentry attitude tracking problem under aerodynamic parameter variations and external disturbances.Design/methodology/approachThe robust control scheme is composed of dynamic surface control (DSC) and least squares support vector machines (LS‐SVM). DSC is used to design a nonlinear controller for HSV; then, to increase the robustness and improve the control performance of the controller. LS‐SVM is presented to estimate the lumped uncertainties, including aerodynamic parameter variations and external disturbances. The stability analysis shows that all closed‐loop signals are bounded, with output tracking error and estimate error of LS‐SVM weights exponentially converging to small compacts.FindingsSimulation results demonstrate that the proposed method is effective, leading to promising performance.Originality/valueFirst, a robust control scheme composed of DSC and adaptive LS‐SVM is proposed for NSV's reentry attitude tracking problem under aerodynamic parameter variations and external disturbances; second, the proposed method can achieve more favorable tracking performances than conventional dynamic surface control because of employing LS‐SVM to estimate aerodynamic parameter variations and external disturbances.

Fault tolerant control for near space vehicle: A survey and some new results

A review on fault-tolerant control (FTC) for near space vehicle (NSV) is presented. First, the concept of near space is introduced, the background of NSV is emphasized, and the model characteristics of NSV in faulty case are investigated. Then, a comparison of different existing approaches is briefly carried out, and achievements on the current research in this field are also presented in the view of the practical application. Furthermore, several existing advanced FTC results for nonlinear flight control systems are given. Finally, the recent literature of NSV are pre- sented to provide an overall view of future developments in this area.