Haibin Sun

Continuous Finite-Time Output Regulation for Disturbed Systems Under Mismatching Condition

In this technical note, the problem of finite-time output regulation control for a class of disturbed system under mismatching condition is investigated via a composite control design manner. The composite controller is developed by using a finite time control technique and a finite time disturbance observer (FTDO). A key idea is to design virtual control laws based on estimation values of the disturbances and the ith (1 ≤ i ≤ n - 1 where n is the order of the system) order derivative of disturbances. Finite time stability analysis for the augmented system is presented by means of Lyapunov stability theorems, which shows that the system output is regulated to zero in finite time even in the presence of mismatched disturbances. A motion control application demonstrates the effectiveness and attractive properties of the proposed method.

Composite controller design for an airbreathing hypersonic vehicle

In this paper, a tracking control problem for the longitudinal model of an airbreathing hypersonic vehicle subject to external disturbances is investigated. Based on the characteristics of the longitudinal model, the model is divided into two subsystems, including an altitude subsystem and a velocity subsystem. A novel ideal is that, for each subsystem, some nonlinear coupling terms are considered to be parts of lumped disturbances, which are estimated by a nonlinear disturbance observer, and a corresponding feedforward design is then implemented to compensate the lumped disturbances. Meanwhile, by using a finite time control technique, a continuous finite time control law is introduced in the feedback control design. Then, a composite control scheme is obtained, which consists of a feedback control law based on the finite time control technique and a feedforward compensator based on the nonlinear disturbance observer technique. This scheme can guarantee stable tracking of the reference trajectories of velocity and altitude. Finally, simulation results are provided to demonstrate the effectiveness of the proposed method. The results show that the control performance of the proposed method in terms of both tracking and disturbance rejection are considerably better than the traditional method.

Robust adaptive integral-sliding-mode fault-tolerant control for airbreathing hypersonic vehicles

In this article, the problem of robust fault-tolerant tracking control is investigated for the longitudinal model of airbreathing hypersonic vehicle in the presence of actuator faults and external disturbances. First, a fault-tolerant control strategy based on finite time integral sliding mode is presented for the longitudinal model of airbreathing hypersonic vehicle, which guarantees that velocity and altitude track their reference signals in finite time. However, this method needs to know the minimum value of actuator efficiency factor and the upper bound of external disturbances. Then, an improved adaptive fault-tolerant control scheme is developed, where two adaptive laws are used to estimate the upper bound of external disturbances and the minimum value of actuator efficiency factor. Finally, simulation results show that the proposed control strategy is effective in rejecting external disturbances and handling actuator faults.

Adaptive fault-tolerant controller design for airbreathing hypersonic vehicle with input saturation

The problem of fault-tolerant control is discussed for the longitudinal model of an airbreathing hypersonic vehicle (AHV) with actuator faults and external disturbances. Firstly, a fault-tolerant control strategy is presented for the longitudinal model of an AHV, which guarantees that velocity and altitude track their reference trajectories at an exponential convergence rate. However, this method needs to know the minimum value of the actuator efficiency factor and the upper bound of the external disturbances, which makes it not easy to implement. Then an improved adaptive fault-tolerant control scheme is proposed, where two adaptive laws are employed to estimate the upper bound of the external disturbances and the minimum value of the actuator efficiency factor, respectively. Secondly, the problem of designing a control scheme with control constraints is further considered, and a new adaptive fault-tolerant control strategy with input saturation is designed to guarantee that velocity and altitude track their reference trajectories. Finally, simulation results are given to show the effectiveness of the proposed methods.

Finite-Time Control for 6DOF Spacecraft Formation Flying Systems

AbstractThis paper considers the finite-time control problem of 6DOF spacecraft formation flying (SFF) systems in the presence of external disturbances. First of all, based on nonsingular terminal sliding mode (NTSM) method, a local finite-time control law is proposed. Then a finite-time disturbance observer (FTDOB) is introduced to estimate the disturbances, and a composite control law which consists of a feedback control law based on NTSM method and a feed-forward compensation term based on FTDOB technique is constructed such that the follower spacecraft can track the desired trajectory in finite time. The major merit of the proposed method is that chattering is substantially reduced because the switching gain of the discontinuous control law is only required to be greater than the bound of disturbance estimation error rather than that of the disturbances. Furthermore, based on switching control method, continuous NTSM and FTDOB technique, a global finite-time control law is developed for 6DOF SFF syste...