Inflatable Robotic Manipulator for Space Debris Mitigation by Visual Servoing

Abstract

This paper describes the latest application of the inflatable robotic manipulator called POPUP. It consists of two inflatable links, made of fibers with high elastic module, electric motors and a gripper. This architecture allows volume and weight reduction, still maintaining the same payload compared to traditional solutions if the internal pressure is set properly. This robot, specifically designed for space application, here goes into action for debris mitigation by means of a vision system. First, some of the aspects related to the physical modelling are discussed to point out the working ranges of such a system, mainly defined by wrinkling effects. Then, a debris capture procedure is simulated to investigate the possibility to catch the target despite the soft nature of the robot. The multibody model takes into account robot dynamics and contact forces with the target. A control strategy based on closed loop inverse kinematics and visual servoing is proposed. The strategy relies on joint velocity command, computed starting from signals of two camera systems, one observing from the robot base, another moving with the end-effector. This ensures the correct tracking of the target and allows to overcome potential errors deriving from a flexible kinematic chain. Results show the POPUP successfully reaching the target and dictate the next steps for a real-world application.