Configuration Optimization for Free-Floating Space Robot Capturing Tumbling Target

Abstract

The maximum contact force is one of the most important indicators for contact problems. In this paper, the configuration optimization is conducted to reduce the maximum contact force for a free-floating space robot capturing tumbling target. First, the dynamics model of a free-floating space robot is given, with which the inertial properties perceived at the end-effector can be derived. Combing the inertial properties of the contact bodies, a novel concept of integrated effective mass is proposed. It tries to transform the complex contact process into the energy change of a virtual single body with integrated effective mass. On this basis, a more general continuous contact model is established, which is also suitable for non-central collisions between space robot and the tumbling target. Thereafter, the maximum contact force is derived as an important indicator for the null-space optimization method to reduce the maximum contact force. Finally, numerical simulations with a 3-degree-of-freedom free-floating space robot and a 7-degree-of-freedom free-floating space robot, as the research objects, are carried out respectively and the results show the effectiveness of the method proposed.

Risk Assessment Model-Guided Configuration Optimization for Free-Floating Space Robot Performing Contact Task

“…And the analytical expression of the maximum contact force can be approximately expressed as [20] ( )…”

“…This method can improve the computational efficiency, and give an analytic solution of the contact information, but there exist singularity problems for certain configurations, and for the space robot in free-floating mode, especially with the initial velocity of the base, there exists an obvious error of the contact information. In the follow-up research, Zhang solves the problems of singularity and obvious errors for certain cases by introducing the base attitude variable into the integrated effective mass and gives the analytical expression of the maximum contact force under non-central contact for the first time [20].…”