A semi-autonomous compound motion pattern using multi-flipper and multi-arm for unstructured terrain traversal

Disaster response crawler robot OCTOPUS has four arms and four flippers for better adaptability to disaster environments. To further improve the robot mobility and terrain adaptability in unstructured terrain, we propose a new locomotion control method called compound motion pattern (CMP) for multi-limb robots like OCTOPUS. This hybrid locomotion by cooperating the arms and flippers would be effective to adapt to the unstructured terrain due to combining the advantages of crawling and walking. As a preliminary study on CMP, we proposed a fundamental and conceptual CMP while clarifying problems in constructing CMP, and developed a semi-autonomous control system for realizing the CMP. Electrically-driven OCTOPUS was used to verify the reliability and correctness of CMP. Results of experiments on climbing a step indicate that the proposed control system could obtain relatively accurate terrain information and the CMP enabled the robot to climb the step. We thus confirmed that the proposed CMP would be effective to increase terrain adaptability of robot in unstructured environment, and it would be a useful locomotion method for advanced disaster response robots.