Motion control of a snake robot on multiple inclined planes

This paper proposes a control method to realize trajectory tracking for snake robots on multiple inclined planes. By explicitly controlling the relative relationship between the robot and the environmental plane, the robot gets into contact with the environmental plane and operates while switching the grounded plane during propulsion. The robot is controlled based on a kinematic model to follow the position and orientation of the head to target trajectory along each plane. The kinematic model is derived by combining the velocity constraint indicating that the wheels do not slip laterally and the kinematic relationship between the robot and the environmental plane. By switching the constraint conditions and the controlled variables, both the head trajectory tracking and maintaining the appropriate relative relationship between the robot and the environmental plane is realized. The effectiveness of the proposed control method was verified through experiments using a physical simulator, and the proposed methods realized the head trajectory tracking on the multiple planes. However, in experiments with actual robot, errors in joint angles and position and rotation of the head accumulated in the direction of the robot body, making it impossible to maintain the appropriate relative relationship, and propulsion was not achieved.