On robust estimation of the location parameter

AIAA Guidance, Navigation, and Control Conference

The science objectives of a spacecraft mission place stringent performance requirements on the spacecraft attitude control system. However, it remains an open problem how to guarantee consistent control performance necessary to meet these requirements, especially in the event of actuator faults and input saturation. Motivated by this fact, in this paper, we address the problem of attitude tracking control with prescribed performance guarantees for a rigid spacecraft subject to unknown but constant inertia parameters, unexpected disturbances, actuator faults, and input saturation. First, certain performance functions specified a priori by the designer are adopted to impose desired performance metrics on the attitude tracking errors. Then, the original attitude tracking error dynamics with performance constraints is transformed into an equivalent “state-constrained” one whose robust stabilization is shown to be sufficient to solve the stated problem via a novel error transformation. Subsequently, based on the transformed system, an adaptive fault-tolerant controller is derived by incorporating backstepping control, the barrier Lyapunov function, and Nussbaum gains. It is proved that the designed controller is able to guarantee the satisfaction of the prespecified constraints on the transformed errors, as well as the boundedness of all other closed-loop signals, without resorting to a judicious selection of the control parameters. Finally, the effectiveness of the proposed control scheme is evaluated by means of simulation experiments carried out on a microsatellite.

Adaptive Fault-Tolerant Attitude Tracking Control of Spacecraft With Prescribed Performance

A smooth attitude-stabilizing control law is derived from which known limits on the control authority of the system are rigorously enforced. Unknown disturbance torques, assumed to be of lesser magnitude than the control limits, are included in the formulation. A smooth control signal containing hyperbolic tangent functions that rigorously obeys a known maximum-torque constraint is introduced. The controller can be viewed as a smooth analog of the variable-structure approach, with the degree of sharpness of the control permitted to vary with time according to a set of user-defined parameters. Lyapunov analysis is employed to ensure global stability, and asymptotic convergence of the angular velocity is guaranteed via the Barbalat lemma. Attitude errors, expressed as Euler parameters, are shown via simulation to vanish whenever certain design parameters are selected appropriately, and guidelines for selection of those parameters are provided in depth.

Globally stabilizing saturated attitude control in the presence of bounded unknown disturbances

This brief examines the problem of attitude tracking control with prescribed performance guarantees for a spacecraft subjected to actuator faults and input saturation. To pursue this, the open-loop tracking error dynamics with certain designer-specified performance constraints is first transformed into an equivalent “state-constrained” one, via an error transformation; furthermore, the resulting dynamics is augmented with a dynamic system, which is tactfully constructed to ensure that the control input satisfies the magnitude limits. Subsequently, a robust fault-tolerant controller is developed by using a low-pass filter and an auxiliary system in conjunction with adaptive backstepping design. It is shown that the control algorithm developed not only achieves the stable attitude tracking with prescribed behavioral metrics but also guarantees the boundedness of all the closed-loop signals. Finally, simulation results are given to evaluate the efficacy of the proposed scheme.

Fault-Tolerant Prescribed Performance Attitude Tracking Control for Spacecraft Under Input Saturation

Fixed-time extended state observer based non-singular fast terminal sliding mode control for a VTVL reusable launch vehicle

Spacecraft play an increasingly important role in various areas of modern society, such as telecommunication, earth observation, and space exploration It is estimated that there have been more than 7000 spacecrafts launched all over the world Despite rigorous testing many of these spacecraft fail on orbit due to various reasons [1], which consequently often lead to the failure of the whole mission According to [2], over 30% of spacecraft failures occur at the subsystem level of the Attitude and Orbit Control System (AOCS) Moreover about 50% of the AOCS failures are attributed to actuator errors The purpose of this paper is to present an actuator fault-tolerant attitude control

/pdf/adaptive-fault-tolerant-control-of-spacecraft-attitude-441hbxgyvp.pdf

Adaptive Fault-Tolerant Control of Spacecraft Attitude Dynamics with Actuator Failures

INS/VisNav/GPS relative navigation system for UAV

Adaptive fault-tolerant control for a VTVL reusable launch vehicle

This paper studies a novel adaptive fixed-time sliding mode attitude tracking control for a submarine-launched missile, which is affected by sea winds, sea waves, ocean currents and other disturbances during the water-exit process. Firstly, the nonlinear water-exit dynamic model of the submarine-launched missile is established, and then it is transformed into a simple second-order attitude tracking system. Subsequently, a novel non-singular fixed-time fast terminal sliding mode surface (NFFTSMS) with fixed-time convergence is presented, and the pre-established settling time is also developed. Moreover, a novel adaptive non-singular fixed-time fast terminal sliding mode control (ANFFTSMC) is presented by employing a fixed-time disturbance observer, a fixed-time differentiator and the proposed NFFTSMS. Closed-loop stability of the proposed controller is proved by utilizing the Lyapunov methodology. Finally, numerical simulations including two typical launch trajectories of the missile are carried out to demonstrate the strong robustness of the proposed control scheme.

Naigang Cui

Papers

Fixed-time extended state observer based non-singular fast terminal sliding mode control for a VTVL reusable launch vehicle

Adaptive Fault-Tolerant Control of Spacecraft Attitude Dynamics with Actuator Failures

INS/VisNav/GPS relative navigation system for UAV

Adaptive fault-tolerant control for a VTVL reusable launch vehicle

Fixed-time sliding mode attitude tracking control for a submarine-launched missile with multiple disturbances