Modeling for Hybrid Obstacle-Aided Locomotion (HOAL) of Snake Robots

Abstract

Snake robots able to operate in cluttered environments will be fit for a multitude of applications pertinent for society such as search-and-rescue operations, fire fighting and traversing otherwise unavailable tight spaces. Obstacle-aided locomotion is a propulsion strategy suitable for such applications, where obstacles in the workspace of the robot are used as assets for forward propulsion instead of avoided as hindrances in the path of the snake. To enable this, this paper extends and adapts the notion of classical hybrid position/force control and related concepts to obstacle-aided locomotion of snake robots. The resulting framework is denoted Hybrid Obstacle-Aided Locomotion (HOAL). The resulting library of concepts and notations and a suitable model of the snake robot and its environment enable us to partition the available degrees of freedom into orthogonal subspaces where control schemes for force and motion can be implemented independently. Furthermore, part of the mathematical model that makes up HOAL is presented to motivate its functionality.