Modular snake robot velocity for side-winding gaits

This paper considers a kinematic model that captures the speed and heading angle of a modular snake robot performing side-winding gaits. Modular snake robot locomotion is controlled in joint space. Consequently, the motion is achieved by continuous changes of the robot's body shape. In light of this behavior, this work describes a method to determine the position and orientation of a floating frame of reference to capture the robot's attitude in real-time, while executing side-winding gaits. A simple velocity model based on ground static contacts that determine the magnitude and direction of the robot's motion is proposed based on that frame. This model is validated by comparisons with experiments. The benefit of the proposed floating frame formulation and the velocity model for side-winding gaits depends on the fact that their calculation relied only in the gait control parameters, hence they could be determined analytically on-line.