Yueyong Lv

6 DOF synchronized control for spacecraft formation flying with input constraint and parameter uncertainties.

This paper treats the problem of synchronized control of spacecraft formation flying (SFF) in the presence of input constraint and parameter uncertainties. More specifically, backstepping based robust control is first developed for the total 6 DOF dynamic model of SFF with parameter uncertainties, in which the model consists of relative translation and attitude rotation. Then this controller is redesigned to deal with the input constraint problem by incorporating a command filter such that the generated control could be implementable even under physical or operating constraints on the control input. The convergence of the proposed control algorithms is proved by the Lyapunov stability theorem. Compared with conventional methods, illustrative simulations of spacecraft formation flying are conducted to verify the effectiveness of the proposed approach to achieve the spacecraft track the desired attitude and position trajectories in a synchronized fashion even in the presence of uncertainties, external disturbances and control saturation constraint.

Input-to-state stable cooperative attitude regulation of spacecraft formation flying

Abstract In this paper, the problem of cooperative attitude control under the concept of input-to-state stability for spacecraft formation flying is discussed in the presence of external disturbances. More specifically, the relative attitude quaternion and relative angular velocity are firstly introduced to describe the relative attitude motion between different formation agents. A novel proportional-derivative type controller is then developed including bounded cooperative attitude control term composed of relative quaternion and angular velocity. Associated Lyapunov stability analysis shows that the closed-loop system is proved to be semi-globally input-to-state stable from the generalized disturbance (i.e. cooperative attitude control term and external disturbance) to system states. Besides, the selecting constraint on control parameters is given in the sense of input-to-state stability as one of the main contributions of this paper. Numerical simulation results are also presented which not only highlight the ensuring closed-loop performance benefits from the control law derived here but also shows a rapid transient process and high accuracy.

Backstepping sliding mode control for combined spacecraft with nonlinear disturbance observer

To attenuate the effects of inertia uncertainty and external disturbance of combined spacecraft on attitude control accuracy and stability, a composite control law by combining nonlinear disturbance observer (NDO) and backstepping sliding mode control is proposed. In this paper, the nonlinear disturbance observer (NDO) is added to observe the unknown inertia and external disturbance, and asymptotic stability of the backstepping sliding mode control with NDO is demonstrated. The performance of the proposed attitude control for combined spacecraft is discussed, and the simulation results demonstrate the effectiveness and feasibility of the proposed controller.

Attitude cooperative control of spacecraft formation via output‐feedback

Purpose – The purpose of this paper is to propose a decentralized output feedback controller for cooperative attitude regulation of spacecraft formation in absence of angular velocity feedback.Design/methodology/approach – The nonlinear relative attitude dynamic and kinematic equations represented by relative quaternion and relative angular velocity, respectively, are considered in this paper. The lead filter is employed to synthesize virtual angular velocity signal so that the design of output feedback controller is achieved. Lyapunov method is adopted to prove the stability of closed‐loop system. Considering the external disturbance, the theory of L2‐gain disturbance attenuation is employed to improve the designed controller. Numerical simulations are carried out to verify the controllers proposed.Findings – It is found that the closed‐loop system can be guaranteed asymptotically stable in absence of external disturbance. When disturbance is considered, as long as the sufficient condition proposed is sa...

Finite-time attitude quantised control for rigid spacecraft

ABSTRACT This paper investigates the quantised finite-time attitude control for rigid spacecraft in the presence of external disturbance. First, a novel quantiser is designed with the combination and improvement of the traditional hysteresis logarithmic quantiser and hysteresis uniform quantiser, so that the innovative quantiser in this paper has the advantages of both hysteresis and uniform quantisers in ensuring chattering free and acceptable quantisation errors for better transient and steady-state performances. Second, a finite-time controller is synthesised even under disturbances and quantisation errors, and the closed-loop system/state converges to the region near zero in finite time. Finally, the attitude stabilisation and attitude tracking simulation results for the rigid spacecraft are presented to illustrate the effectiveness and feasibility of the proposed control strategy.

Cooperative Surrounding Control with Collision Avoidance for Multiple Euler-Lagrange Systems

This paper investigates the cooperative surrounding control problem for the multi-agent systems with nonlinear Euler-Lagrange dynamics. To guarantee the motion safety for the multi-agent systems, a cooperative surrounding control algorithm with collision avoidance is proposed for each agent such that all agents can surround the static target by applying the potential function between each agent and its neighbors into the control algorithm. At the same time, the configuration among target and agents is formed in the process of surrounding. The Lyapunov theory is used to prove the stability of the cooperative surrounding control algorithm. Finally, the simulation example illustrates the effectiveness of the proposed control algorithm.

Super-twisting Sliding Mode Observer Based Finite-Time Attitude Control of Combined Spacecraft

A novel finite-time controller integrated with disturbance observer is proposed for a combined spacecraft in the presence of inertia uncertainty and external disturbance. As a stepping-stone, a super-twisting sliding mode disturbance observer(STDO) is designed firstly such that the reconstruction of lumped disturbances is accomplished in finite time and the observer error is convergence. Then, with the reconstructed information, a finite-time controller synthesized with the backstepping method, and command filter is used to avoid the too cumbersome analytic derivation, then the closed-loop system/state is proved to be finite-time stable. Numerical simulation results for the combined spacecraft show good performances, which validate the effectiveness and feasibility of the proposed scheme.

Switch-based adaptive nonsingular sliding mode control for spacecraft formation flying

This paper investigates the relative position control problem for a two-agent spacecraft formation. The modified nonlinear dynamic based on C-W equation is adopted to describe relative position between the leader and follower. Considering the system uncertainty and external disturbance, adaptive sliding mode control laws based on linear and terminal sliding surface are proposed respectively. In addition, a switching mechanism is employed to make a selection between the general and terminal surfaces so as to avoid singularity. The convergence of closed-loop system is proved by Lyapunov stability theory. Numerical simulations illustrates the validity of the control law proposed.

Back-stepping based integrated orbit and attitude control for on-orbit servicing spacecraft

This paper investigates the integrated orbit and attitude modelling and control problem for on-orbit servicing spacecraft. The integrated relative kinematic and dynamic model for the on-orbit servicing spacecraft and the target is established on the base of dual-quaternion. A backstepping control law is proposed, which is improved then in consideration of system uncertainties. Globally asymptotical stability is analyzed through Lyapunov stability for the closed-loop system. Numerical simulations demonstrate the effectiveness and validity of the proposed methods.

Terminal sliding mode attitude control for satellite

A finite time control method based on terminal sliding mode (TSM) is presented for satellite attitude control system in this paper. Using the concepts of finite time stability and TSM, a finite time stable sliding mode is designed, and then a continuous TSM finite time controller using the inverse dynamic method is designed for the second-order dynamic system of the satellite. In order to eliminate the oscillation, a new type of saturation function is also designed to replace the conventional symbolic function. The validity for the proposed algorithm is testified through simulations.