A Dimension Reduced Ground Test Method of Dual-arm Space Robot for On-orbit Assembly

Dual-arm space robot used in on-orbit assembly is a free-floating space robot system. The key points of the prelaunch ground test are the realization of microgravity environment and the dynamics equivalent model of space robot. For a free-floating dual-arm space robot consists of one floating base and two six-DOF (degree of freedom) arms, we proposed an air bearing based ground microgravity test method. IMU (inertial measurement unit) and thrusters are mounted on the large base to monitor and counteract the disturbance of dual-arm motion to the base, respectively. A multipoint dynamic gravity compensation mechanism is designed to maintain the microgravity status of the robot in motion. The mechanism can avoid mutual interference of links. The dimension reduced three-DOF dynamics equivalent model in a plane is built from the six-DOF space arm. Finally, the method is validated by tracking the on-orbit trajectory of dual-arm unfolding and component assembly on an air bearing bed.