Modified active disturbance rejection control scheme with sliding mode compensation for airborne star tracker driven by Permanent Magnet Synchronous Motor. (October 2022)

• Record Type: Journal Article
• Authors: Wang, Fan; Cheng, Tianji; Zhu, Hua; Liu, Zhiwen; Han, Chongyang; Wang, Ranjun; Liu, Enhai
• Is Part Of: Control engineering practice. Volume 127(2022)
• Publication Date: 2022-10
• Subjects: Star tracker -- Active disturbance rejection control (ADRC) -- Robustness -- Modified extended state observer (MESO) -- Input to state stability (ISS) -- Sliding mode (SM) control; Automatic control -- Periodicals; 629.89
• DOI: 10.1016/j.conengprac.2022.105267
• Languages: English
• ISSNs: 0967-0661

Abstract

Abstract: For an airborne star tracker, pointing and switching the target stars with high precision and fast response is necessary for the star observation. However, under airborne circumstances, the control performance of star tracker will be deteriorated by multiple types of disturbance. Therefore, the disturbance suppression is indispensable. In this paper, a high-precision position control scheme for a Permanent Magnet Synchronous Motor (PMSM) driven airborne star tracker is presented based on active disturbance rejection control (ADRC) to overcome the disturbance and improve the robustness of the system. Firstly, to reduce the disturbance estimation error, a modified extended state observer (MESO) with predictive factor is proposed. The stability analysis verifies its feasibility based on input to state stability (ISS) framework and parameter tuning method of MESO via frequency domain analysis is also given. Secondly, aiming at the problem of insufficient disturbance compensation ability of classical ADRC because of the estimation error in control gain and of chattering phenomenon in the conventional sliding mode control, a chattering-reduced sliding mode (SM) component is added to the state error feedback. It is proved that the SM component can make the system reach the sliding surface in limited time via Lyapunov theory and the closed loop stability of the controller can also be ensured. Finally, comparative simulations and experiments are conducted to verify the effectiveness of the proposed control scheme. The simulations show the superiorities of the proposed methods in anti-disturbance capability and robustness. The experimental results testify to the feasibility and better performance of the proposed methods in practical applications of star tracker. Highlights: A novel ADRC scheme is proposed for the pointing and positioning of star tracker. A modified ESO (MESO) with predictive factor is put forward for better states estimation performance. A novel chattering-free sliding component is added in the feedback of the controller. Stability and frequency analysis testifies the theoretically feasibility of the proposed methods. Comparative simulations and experiments validate the effectiveness of proposed control scheme.