An enhanced anti-disturbance guidance scheme for powered ... › publication › fulltext › An-enhan... › publication › fulltext › An-enhan...by J Xu · 2018 · Related articlesscheme for powered descent phase of Mars landing under actuator fault. Jianwei Xu1
An enhanced anti-disturbance guidance scheme for powered descent phase of Mars landing under actuator fault
International Journal of Advanced Robotic Systems January-February 2018: 1–9 ª The Author(s) 2018 DOI: 10.1177/1729881418759889 journals.sagepub.com/home/arx
Jianwei Xu1, Jianzhong Qiao1,2 and Lei Guo1,2
Abstract As a class of autonomous deep-space exploration robots, Mars lander is simultaneously affected by wind disturbance and actuator fault, which hinders precise landing on Mars. In this article, we propose a composite guidance approach by combining disturbance observer and iterative learning observer together. The Mars wind disturbance is dealt by the disturbance observer providing wind estimation which is rejected through feed-forward channel. Meanwhile, the iterative learning observer is used to estimate the deficiency of actuators. The proposed guidance scheme ensures not only the precision but also the reliability of the Mars guidance system. The stability of the closed-loop system is analyzed. Simulations made in different situations demonstrate the performance of the proposed approach. Keywords Powered descent phase, precise landing on Mars, iterative learning observer, disturbance observer, enhanced anti-disturbance guidance Date received: 5 July 2017; accepted: 22 January 2018 Topic: Special Issue—Intelligent Control Methods in Advanced Robotics and Automation Topic Editor: Andrey V Savkin Associate Editor: Junzhi Yu
Introduction Powered descent phase is the final regulation phase in Mars landing tasks.1,2 Unfortunately, landers will inevitably face Mars wind disturbance, which may result in far range away from the prespecified landing point, sometimes it even causes a crush into the ground.3–5 Besides, the Mars landing mission needs to endure a long stage including launching from the earth, in-orbit flying, and landing. Therefore, landers will probably occur fault which leads to the safety problem of landers.6,7 Reviewing the past 46 Mars exploration missions since 1960, only eight landing missions were successfully achieved due to the strong impact of disturbance and fault during the Mars landing process.8,9 Overall, improving the precision and reliability of Mars landers is a key issue that needs to be addressed.
Considering dynamics and constraints of the spacecraft guidance system, Apollo guidance approach gives a comprehensive reference trajectory satisfying mission requirements. A simple guidance framework is then set up to cancel the tracking error preserving the nominal performance. With the advantage of low calculation cost and
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School of Automation Science and Electrical Engineering, Beihang University, Beijing, China 2 Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Beihang University, Beijing, China Corresponding authors: Jianzhong Qiao and Lei Guo, School of Automation Science and Electrical Engineering, Beihang University, No. 37 Xueyuan Road, Haidian District, 100191, Beijing, China. Emails:
[email protected];
[email protected]
Creative Commons CC BY: This article is distributed under the terms of the Creative Commons Attribution 4.0 License (http://www.creativecommons.org/licenses/by/4.0/) which permits any use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/ open-access-at-sage).
2 parameters preassigned, the guidance technique of Apollo has been successfully applied in Lunar and Mars space exploration missions since 1970s.10–12 Gradually, based on the Apollo method and its extension, a great deal of attention has been focused on the guidance problem using zero-effort-miss/zero-effort-velocity theory, optimal nonlinear feedback guidance algorithm, and sliding mode guidance approach during Mars landing process. 13–17 Nevertheless, most studies ignore the effect of disturbances or just regard the disturbance as a norm bounded vector. Abandoning the prior information or not using measurable signals will bring great conservativeness to the system. Consequently, landers may consume extra energy when coming into unexpected disturbances during the landing process. Recently, anti-disturbance control theory is widely applied due to its advantage of achieving a better performance by fully making use of attainable disturbance information.18–21 The essential virtue of the anti-disturbance control has been introduced into the Mars landing problem to improve the anti-disturbance performance of landing system.22,23 Although guidance command is calculated to improve the precision of landers, unresolved actuator fault or deficiency issues still limit the ability of safely delivering the Mars lander to the prescribed landing point. Until now, some effective active and passive tolerant control methods have been provided to solve fault problems like partial loss of actuator effectiveness, saturation constraints, control allocation, and controller degradation.24–29 Recently, intelligent methods including adaptive-proportional int
