Characteristic model-based H 2/H ∞ robust adaptive control during the re-entry of hypersonic cruise vehicles

Abstract

This paper aims at introducing H 2 and H∞ robustness into the well-known characteristic modelbased golden-section adaptive control law, and applying the robust adaptive control scheme to the attitude control of hypersonic cruise vehicles that are subject to external disturbances and aerodynamic coefficients uncertainties. When maneuvering at ultra high speeds, the attitude system of the hypersonic cruise vehicle is extremely sensitive to external disturbances and aerodynamic coefficients variations, and therefore the adaptiveness and the robustness of the attitude system are crucial during the controller design. To enhance the robustness of the existing golden-section adaptive control law, a golden-section robust adaptive control law is proposed. Compared to the existing control law where the design of the parameter λ depends on experience and is carried out offline, linear matrix inequality-based synthesis of λ is proposed such that the closed-loop system is stable with guaranteed H 2 and H∞ performance. It is suitable for online computing and provides a time-varying λ(k) that is adjusted towards the optimal H 2 and H∞ performance. When being applied to the attitude control of hypersonic vehicles during re-entry, the adaptive nature of the proposed control law provides the attitude system the capability to accommodate large flight conditions, and its H 2 and H∞ robustness brought by λ(k) guarantees satisfying tracking performance in the presence of disturbances including both external disturbance and absolute aerodynamic coefficients errors. Keywords golden-section adaptive control, characteristic model, H 2 and H∞ analysis, hypersonic vehicle, attitude control Citation Huang H, Zhang Z. Characteristic model-based H2/H∞ robust adaptive control during the re-entry of hypersonic cruise vehicles.

Sampled-data feedback and stability for a class of uncertain nonlinear systems based on characteristic modeling method

“…At this point, we have shown the characteristic model (10) of the error system (7) and the corresponding golden-section adaptive control (14). Moreover, it can be seen from (14) that our proposed control law has a simple linear structure, rendering it convenient for engineering applications.…”

“…The performance of the closed-loop system under the golden-section adaptive controller given in (14) is demonstrated by the following theorems. For convenience, we introduce the time invariant matrix…”

“…In addition, the equivalence in the output of the resultant characteristic models and controlled plants has been investigated. As regards the closed-loop stability problem, current research is primarily restricted to stability analysis of discrete-time closed-loop systems consisting of characteristic models and corresponding discrete-time controllers (e.g., [1,[11][12][13][14]). However, very little research has been conducted on hybrid closed-loop systems comprised of continuous plants and sampled-data controllers.…”

Attitude controller design for reusable launch vehicles during reentry phase via compound adaptive fuzzy H-infinity control

“…This control approach is an efficient way to cope with the model uncertainties and external disturbances even if the boundaries of uncertainties and disturbances are unknown. Moreover, FLS are always combined with other control strategies, such as adaptive control [35], robust control [36], fault-tolerant control [37] and so on, with the goal to improve the tracking control performance of the flight control system and achieve a good robustness simultaneously. Besides, adaptive fuzzy control method is often combined with robust or Hinfinity control method in many applications [38][39] [40].…”

Second-order continuous characteristic model based adaptive control for a class of linear systems

“…Therefore, it is significant to alter the old modeling method based on accurate dynamic and mathematical description or based on approximation through lowering order with a new modeling method based upon plant characteristic description. To overcome these difficulties, an integrated and practical all-coefficient adaptive control theory and method based on the discrete characteristic model were proposed by Wu in 1980s, and have already been applied to many fields such as astronautics and industry successfully [5][6][7][8][9][10][11]. The so-called characteristic modeling is based on both the plant dynamic characteristics and control performance requirements, rather than based on only accurate plant dynamic analysis.…”