Research and Ground Verification of the Force Compliance Control Method for Space Station Manipulator

Abstract

The space station manipulator does lots of tasks with contact force/torque on orbit. To ensure the safety of the space station and the manipulator, the contact force/torque of manipulator must be controlled. Based on analyzing typical tasks’ working flows and force control requirements, such as ORU (orbit replacement unit) changeout and dual arm collaborative payload transport, an impedance control method based on wrist 6 axis force/torque feedback is designed. For engineering implementation of the impedance control algorithm, the discretization method and impedance control parameters selection principle are also studied. To verify the compliance control algorithm, a ground experiment platform adopting industrial manipulators is developed. In order to eliminate the influence of gravity, a real-time gravity compensation algorithm is proposed. Then, the correctness of real-time gravity compensation and force compliance control algorithm is verified on the experiment platform. Finally, the ORU replacement and dual arm collaborative payload transport experiments are done. Experimental results show that the force compliance control method proposed in this paper can control the contact force and torque at the end of the manipulator when executing typical tasks.

ACP-Based Space Systems: Design, Development, and Operation

“…The NASA Johnson Space Center has spearheaded the development of the Trick General-purpose Simulation Environment, which is an open-source project. It has been applied in flight control tasks for projects such as the Orion spacecraft and the Space Station robotic arm [10]. The Jet Propulsion Laboratory (JPL) has utilized Dshell and Darts to establish a general purpose simulation environment that includes the Darts library for flexible multibody dynamic calculations and a component model library.…”