Repetitive Learning Sliding Mode Stabilization Control for a Flexible-Base, Flexible-Link and Flexible-Joint Space Robot Capturing a Satellite

Abstract

During the process of satellite capture by a flexible base–link–joint space robot, the base, joints, and links vibrate easily and also rotate in a disorderly manner owing to the impact torque. To address this problem, a repetitive learning sliding mode stabilization control is proposed to stabilize the system. First, the dynamic models of the fully flexible space robot and the captured satellite are established, respectively, and the impact effect is calculated according to the motion and force transfer relationships. Based on this, a dynamic model of the system after capturing is established. Subsequently, the system is decomposed into slow and fast subsystems using the singular perturbation theory. To ensure that the base attitude and the joints of the slow subsystem reach the desired trajectories, link vibrations are suppressed simultaneously, and a repetitive learning sliding mode controller based on the concept of the virtual force is designed. Moreover, a multilinear optimal controller is proposed for the fast subsystem to suppress the vibration of the base and joints. Two sub-controllers constitute the repetitive learning sliding mode stabilization control for the system. This ensures that the base attitude and joints of the system reach the desired trajectories in a limited time after capturing, obtain better control quality, and suppress the multiple flexible vibrations of the base, links and joints. Finally, the simulation results verify the effectiveness of the designed control strategy.

An Efficient Pose Estimation Algorithm for Non-Cooperative Space Objects Based on Dual-Channel Transformer

“…Non-cooperative space object pose estimation is an urgent problem to be solved in the space field; it has very important application value in relative navigation, rendezvous and docking, active debris removal (ADR) on-orbit servicing (OOS), etc. [1][2][3][4][5][6]. For the special environment of on-orbit work, the pose estimation [7,8] algorithm based on a lowquality, low-power monocular sensor provides a feasible scheme for space application, and it has received extensive attention from scientific research institutions and researchers.…”

A Fuzzy Logic Reinforcement Learning Control with Spring-Damper Device for Space Robot Capturing Satellite

“…At present, it is feasible to use a space robot to complete the capture task. This has therefore become one of the research hot spots of space exploration [1][2][3][4][5][6][7][8]. Generally, the process of capture operation can be divided into four stages: (1) the space robot observes the target satellite; (2) a pre-operation stage before capture operation, such as deceleration and detumbling control of the target satellite;…”

Fuzzy Luenberger Observer Design for Nonlinear Flexible Joint Robot Manipulator

“…Joint compliance transmission mechanisms can be implemented in parallel robotics manipulators to obtain high speed compared to ones that do not have compliance joints [9]. In [10], a fully flexible space robot with fast and flexible joints was used for capturing a satellite. A multilinear optimal controller was used for suppressing the vibration in the joints and the base.…”