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.