Identification of Docking Possibility Criteria including Recovery from Incomplete Grasping of Docking Mechanism for Nanosatellite

Abstract

This paper deals with a docking methodology for inspection and measurement missions with nanosatellites (less than 50kg in mass). According to the proposed docking concept where a docking procedure is divided into an approaching/grasping phase and a guiding phase, a functional test model for docking mechanism is designed and assembled to conduct verification experiments. In the paper, the docking methodology, the docking mechanism, and a docking control algorithm are introduced briefly. Three dimensional microgravity experiments using a drop shaft are conducted. In the experiments, the authors classify grasping conditions into two types called “complete grasping” and “incomplete grasping”. In the complete grasping, the docking mechanism can easily guide the nanosatellite to the docking port, but in case of the incomplete grasping, it is difficult to recover from the incomplete grasping to the complete one. The incomplete grasping condition is explained experimentally, and a guiding control algorithm for recovery from the condition is proposed. Finally, docking possibility criteria are identified, and feasibility of the methodology is clarified.