This research focuses on the detumbling planning and control method for the dual-arm space robot post-capturing a non-cooperative tumbling target, which takes the uncertainty of target's inertial parameters and generalized input constraints of robotic system into consideration. Firstly, based on the concept of task compatibility, an efficient detumbling strategy without optimization algorithm is pro-posed, where the target's desired acceleration is in the opposite direction of its velocity with the magnitude determined by scaling factor. Next, a compliance control scheme is designed to track the desired trajectory and the desired contact forces by establishing impedance control for the target and end-effectors. Finally, considering the target's dynamic uncertainties, an adaptive controller is included to compensate the effects of uncertainty and ensure stable detumbling. The simulation results are presented for detumbling a target with inertial parameter uncertainties using a 7 degree-of-freedom dual-arm space robot, which demonstrate the effectiveness of the proposed method.(c) 2023 COSPAR. Published by Elsevier B.V. All rights reserved.

针对多臂空间机器人以软指接触形式抓捕目标后的情形,提出了一种综合考虑摩擦约束及机械臂能力约束的目标期望合外力的载荷分配方法.首先,建立空间机器人系统与目标的动力学方程,作为载荷分配问题的基础.然后,在地面机器人相关研究的基础上,建立机械臂末端与目标表面的软指接触模型,并建立二者之间的运动约束关系.为简化优化计算,将摩擦锥约束线性化,并建立考虑关节扭矩限制的机械臂能力约束,从而将抓捕力优化的非线性规划问题转化为线性规划问题.最后,采用双臂空间机器人模型进行数值仿真,表明所提方法针对日标各种形式运动进行载荷分配的有效性.

SUMMARYThe dynamic manipulability of a manipulator refers to the capacity to generate accelerations given the joint torques, which is an important indicator for motion planning and control. In this paper, the dynamic manipulability analysis is extended to the multi-arm space robot, and further to the closed-loop system composed of the space robot and the captured target. According to the dynamic equations, the relation between the joint torques and the end-effector accelerations in the open-loop space robot and that between the joint torques and the target accelerations in the closed-loop system are derived. On this basis, the dynamic manipulability factor and dynamic manipulability ellipsoid are proposed as two tools for the dynamic manipulability measure, where the effects of the bias acceleration are considered. The influences of dynamic parameters, link lengths, joint variables, and velocities on the dynamic manipulability measure are mainly studied.

The base pose of a free-floating space robot can be disturbed by the motion of its manipulators. When a multi-arm space robot captures a space target, a closed-loop system will be formed, and the dynamic coupling between the base and manipulators or the target are more complex. This paper analyzes the dynamic coupling effect of the open-loop multi-arm space robot and the closed-loop system. According to the momentum conservation equation, the velocity correlation matrices between the base and the joints or end-effectors in the open-loop free-floating space robot, and those between the base and the joints or target in the closed-loop system are derived. On this basis, the dynamic coupling factors and coupling ellipsoids are proposed as two tools to measure the coupling degree. The coupling factors proposed in this paper are based on the singular values of the correlation matrices to expand the scope of application. The two tools are applied to analyze the coupling of a dual-arm space robot and its composite body with the captured target, where the influences of dynamic parameters, link lengths and joint variables are mainly studied.