Reaction Force Analysis for Obstacle-Aided Locomotion of Snake Robot Using Piecewise Helixes

Snake robots can use numerous joints to move in various manners. One of them is the obstacle-aided locomotion, a method in which a robot moves by pushing obstacles. In our previous study, we proposed a three-dimensional obstacle-aided locomotion using piecewise helixes, which is composed of an obstacle-contacting part and a grounding part. However, this method is imperfect. This is because when depending on the contact condition with obstacles, the reaction force may make it difficult for the robot to maintain contact with the obstacles or to propel itself. In this study, we analyze the reaction force received from obstacles during the obstacle-aided locomotion to improve the performance of the method. Using these analysis results, we evaluate the contact points of the obstacle-contacting part from two perspectives. The first considers the maintenance of contact with the obstacle, and the second considers the factors that interfere with propulsion. The reaction force was confirmed experimentally using a force sensor. Additionally, the theory of the factors that interfere with the propulsion and maintenance of contact with the obstacle was verified using experiments of the obstacle-aided locomotion in several environments.