An Inflatable 7-DOF Space Robotic Arm for Active Debris Removal

In this work a 7-degree-of-freedom inflatable robotic manipulator designed for space applications, named POPUP, is introduced demonstrating the capability to perform active debris removal. The robot has two inflatable links built with high stiffness modulus fibers, is actuated by electric motors, and presents a gripper on its end-effector. This novel design allows to obtain mass and volume reduction at launch, resulting in a cost-effective solution. In the proposed solution the inflatable robot is mounted on a free-floating chaser spacecraft and aims to capture a space debris. The physical model of the system is detailed, including the inflatable link model based on finite elements, under proper described hypothesis. The vision system implemented includes two camera systems: one on the spacecraft, to identify and follow the target, and another on the end-effector of the robot, for accurate final positioning and grasping. The redundancy in robotic architecture is exploited to minimize the norm of joint velocities. Simulation results of debris capture operation are proposed, demonstrating the feasibility of the grasping operation despite the soft links of the robot, and considering possible misalignments due to the inflating procedure, using visual servoing algorithms.