Disturbance observer-based fault-tolerant attitude tracking control for rigid spacecraft with finite-time convergence

Author(s):  
Qun Zong ◽  
Xiuyun Zhang ◽  
Shikai Shao ◽  
Bailing Tian ◽  
Wenjing Liu

In this paper, finite-time fault-tolerant attitude tracking control is investigated for rigid spacecraft system with external disturbances, inertia uncertainties and actuator faults. A novel finite-time disturbance observer combined with a nonsingular terminal sliding mode controller is developed. Using an equivalent output error injection approach, a finite-time disturbance observer with simple structure is firstly designed to estimate lumped uncertainty. Then, to remove the requirement of prior knowledge about lumped uncertainty and reduce chattering, an adaptive finite-time disturbance observer is further proposed, and the estimations converge to the neighborhood of the true values. Based on the designed observer, a unified finite-time attitude controller is obtained automatically. Finally, both additive and multiplicative faults are considered for simulations and the results illustrate the great fault-tolerant capability of the proposed scheme.

2020 ◽  
Vol 29 (13) ◽  
pp. 2050212
Author(s):  
Zhi Gao ◽  
Zhihao Zhu ◽  
Yu Guo

For multi-spacecraft with actuator saturation, inertia uncertainties and external disturbances, a distributed finite-time coordinated attitude tracking control problem for the spacecraft with the communication topology containing fewer information paths is investigated. Aiming at reducing the communication path, a class of distributed finite-time state observers is designed. To speed up the convergence rate of the multiple spacecraft system, a fast nonsingular terminal sliding mode function is proposed. Moreover, an adaptive control term is proposed to suppress the impact of the external state-dependent disturbances and unknown time-varying inertia uncertainties. Further considering the actuator saturation owing to its physical limitations, a saturation function is designed. With the distributed finite-time observers, the fast nonsingular terminal sliding mode function, the adaptive update law and the saturation function, a distributed finite-time coordinated attitude tracking saturation controller is designed. Using the proposed controller, the follower can synchronize with the common leader with time-varying trajectory in finite time. Simulation results demonstrate the effectiveness of the designed controller.


Author(s):  
Cheng Huang ◽  
Yan Wang ◽  
Xing-lin Chen

This paper studies the problem of attitude tracking control for spacecraft rendezvous and docking based on a physical ground simulation system. Two finite-time controllers based on quaternion are proposed by using a novel fast nonsingular terminal sliding mode surface associated with the adaptive control, the novel fast nonsingular terminal sliding mode surface not only contains the advantages of the fast nonsingular terminal sliding mode surface, but also can eliminate unwinding caused by the quaternion. The first controller, which is continuous and chattering-free, can compensate unknown constant external disturbances, while the second controller can both compensate parametric uncertainties and varying external disturbances with unknown bounds without chattering. Lyapunov theoretical analysis and simulation results show that the two controllers can make the closed-loop system errors converge to zero in finite time and guarantee the finite-time stability of the system.


Author(s):  
Bing Huang ◽  
Ai-jun Li ◽  
Yong Guo ◽  
Chang-qing Wang ◽  
Jin-hua Guo

This paper investigates the finite-time attitude tracking control problem for spacecraft in the presence of external disturbances and actuator faults. Two anti-unwinding attitude tracking control schemes have been proposed based on the rotation matrix and sliding mode control technology. Utilizing a fast terminal sliding mode surface, the first controller can fulfill the finite-time attitude tracking control task with disturbance rejection ability. The second controller can improve the system reliability when the actuator fault occurs. Rigorous mathematical analysis and proof concludes that the proposed controllers can make a spacecraft track the desired attitude command in finite time. Numerical simulation results are presented to demonstrate the effectiveness of the proposed controllers.


Author(s):  
Haitao Chen ◽  
Shenmin Song

This article investigates the attitude tracking control problem of a rigid spacecraft under the modeling inaccuracy, environmental disturbance, and input magnitude and rate saturations. A robust controller is proposed based on several nonlinear control methods, including the integral terminal sliding mode control, adaptive control, backstepping control, auxiliary system, and nonlinear observer methods. Within the control framework, a new integral terminal sliding mode surface (ITSMS) is first designed which integrates the fast nonsingular terminal sliding mode surface (FNTSMS) with a first-order filter to achieve the finite time stability without the input singularity problem. And adaptive laws are employed to compensate for the modeling inaccuracy and environmental disturbance with no prior knowledge. To satisfy the input magnitude and rate saturation constraints, a dynamic model in the form of a first-order filter is built up to restrict the dynamics of the actuators, which is then associated with the auxiliary system. Meanwhile, a nonlinear observer is used to avoid calculating the derivative of the expected virtual control signal. Semi-globally uniformly ultimate bounded stability is proved for the closed-loop system, and the tracking errors can converge to small regions around the expected equilibrium in finite time. Finally, numerical simulation results are presented to demonstrate the effectiveness of the proposed controller.


Author(s):  
Zeng Wang ◽  
Yuxin Su ◽  
Liyin Zhang

This paper addresses the finite time attitude tracking for rigid spacecraft with inertia uncertainties and external disturbances. First, a new nonsingular terminal sliding mode (NTSM) surface is proposed for singularity elimination. Second, a robust controller based on NTSM is designed to solve the attitude tracking problem. It is proved that the new NTSM can converge to zero within finite time, and the attitude tracking errors converge to an arbitrary small bound centered on equilibrium point within finite time and then go to equilibrium point asymptotically. The appealing features of the proposed control are fast convergence, high precision, strong robustness, and easy implementation. Simulations verify the effectiveness of the proposed approach.


2021 ◽  
Author(s):  
Jie Wang ◽  
YuShang Hu ◽  
Wenqiang Ji

Abstract This paper investigates the problem of the finite-time attitude tracking control for rigid spacecrafts with external disturbances and inertia uncertainties. Firstly, a finite-time approach is designed to achieve attitude tracking control of the rigid spacecraft in absence of disturbances and inertia uncertainties and the time of convergence can be chosen in advance. Then, the integral sliding mode combined with barrier function-based adaptive laws is proposed to reject the disturbances and inertia uncertainties, and at the same time, a barrier function-based adaptive method can also ensure the solutions of the rigid spacecraft system belonging to a stipulated vicinity of the intended variables starting from the initial moment and the uncertainties' upper bound is not overestimated. Finally, numerical simulation is provided to illustrate the efficiency of the proposed control protocol.


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