Adaptive Fixed-Time Nonsingular Terminal Sliding Mode Attitude Tracking Control for Spacecraft with Actuator Saturations and Faults

Zhiguo Han,Minghao Wang,Hang Qian,Xunliang Yan,Paolo Castaldi

doi:10.1155/2021/8838784

Abstract

This paper focuses on the potential actuator failures of spacecraft in practical engineering applications. Aiming at the shortcomings and deficiencies in the existing attitude fault-tolerant control system design, combined with the current research status of attitude fault-tolerant control technology, we carry out high-precision, fast-convergent attitude tracking algorithms. Based on the adaptive nonsingular terminal sliding mode control theory, we design a kind of fixed-time convergence control method. This method solves the problems of actuator faults, actuator saturation, external disturbances, and inertia uncertainties. The control method includes control law design and controller design. The designed fixed-time adaptive nonsingular terminal sliding mode control law is applicable to the development of fixed-time fault-tolerant attitude tracking controller with multiple constraints. The designed controller considers the saturation of the actuator output torque so that the spacecraft can operate within the saturation magnitude without on-line fault estimation. Lyapunov stability analysis shows that under multiple constraints such as actuator saturation, external disturbances, and inertia uncertainties, the controller has fast convergence and has good fault tolerance to actuator fault. The numerical simulation shows that the controller has good performance and low-energy consumption in attitude tracking control.

Highlights

As my country continues to carry out deep-space missions such as the lunar exploration program and Mars exploration, the requirements for the stability, reliability, and autonomous operation capabilities of the entire spacecraft system, especially the spacecraft control system, have been significantly improved
According to foreign spacecraft’s on-orbit attitude control system failure statistics, actuator and sensor failures accounted for 68% of the entire attitude control system failures, of which actuator failures accounted for 44% and sensor failures accounted for 24%
Fault-tolerant control technology is an effective means to solve this problem without increasing the cost of system design

Summary

Introduction

As my country continues to carry out deep-space missions such as the lunar exploration program and Mars exploration, the requirements for the stability, reliability, and autonomous operation capabilities of the entire spacecraft system, especially the spacecraft control system, have been significantly improved. [11] solves the problem of finite-time fault-tolerant attitude stability control for rigid spacecraft under the conditions of actuator faults or failure, external disturbances, and modelling uncertainty. Under the assumption that the upper bound of the uncertainties is known, the existing literature has designed a high-precision, finite-time convergence attitude fault-tolerant control law They can achieve high precision and stability of the attitude control system, they do not consider other control index requirements, and engineering application value. The convergence time of the system is further reduced, the control saturation can be completely avoided, and less energy consumption is required (2) The attitude convergence time is further reduced, and the performance of the control algorithm is further improved: Combining the design method of sliding mode surface and control law in the existing literature, this paper presents a new control law.

Materials and the Models for Tracking Spacecraft’s Attitude

Step 1

Step 2

Simulation Results Analysis

Conclusions

Future Recommendation