Control of industrial robots for hardware-in-the-loop simulation of satellite docking

摘要

One of the most challenging and risky missions for spacecraft is to perform Rendezvous and Docking (RvD) autonomously in space. To ensure a safe and reliable operation, such a mission must be carefully designed and thoroughly verified before a real space mission can be launched. This paper describes the impact-contact dynamics simulation capability of a new, robotics-based, hardware-in-the-loop (HIL) RvD simulation facility which uses two industrial robots to simulate 6-DOF dynamic maneuvering of two docking satellites. The facility is capable of physically simulating the final approaching within 25-meter range and the entire docking/capturing process in a satellite on-orbit servicing mission. The paper briefly discusses the difficulties of using industrial robots for HIL contact dynamics simulation and how these problems are solved. Admittance control strategy is proposed to control the robotic system to make the robot dynamically behave like the spacecraft during a physical interception. The control strategy works as an outer loop on the top of the existing control system of the industrial robot and hence, it does not require altering the joint control hardware and software which are inaccessible for an industrial robot. A simulation study has shown that the methodology can accurately simulate the impact-contact dynamics behavior of the spacecraft in a docking operation.