Use of Dynamic Scaling for Trajectory Planning of Floating Pedestal and Manipulator System in a Microgravity Environment

In this paper, motion planning and coordination is investigated for a space robot composed of a floating pedestal and manipulator. In some cases, such as a manipulator grasping a higher quality target, the dynamic coupling can occur leading to under-actuation of the floating pedestal (that is, the required control force of the pedestal exceeds the thrust limit). As a result, the desired operation may not be achieved due to large control error. Therefore, we propose an innovative planning method, termed dynamic scaling planning method, to avoid pedestal under-actuation and guarantee accuracy of manipulator operations. Furthermore, to validate the proposed method, an experimental model of a space robot operating in a magnetic-liquid hybrid suspension microgravity simulation environment was developed. Results of the experimental simulations demonstrate that the proposed method can effectively avoid under-actuation of the pedestal. Moreover, the end-effector of the manipulator follows a desired path to successfully reach its target location.