Design and Modeling of a New Drive System and Exaggerated Rectilinear-Gait for a Snake-Inspired Robot

Abstract

In recent years, snake-inspired locomotion has garnered increasing interest in the bio-inspired robotics community. This positive trend is largely due to the unique and highly effective gaits utilized by snakes to traverse various terrains and obstacles. These gaits make use of a snake's hyper-redundant body structure to adapt to the terrain and maneuver through tight spaces. Snakeinspired robots utilizing rectilinear motion, one of the primary gaits observed in natural snakes, have demonstrated favorable results on various terrains. However, previous robot designs utilizing rectilinear gaits were slow in speed. This paper presents a design and an exaggerated rectilinear gait concept for a snake-inspired robot which overcomes this limitation. The robot concept incorporates high speed linear motion and a new multi-material, variable friction force anchoring concept. A series of traction experiments are conducted to determine appropriate materials to be used in the friction anchor design. The gait concept includes four unique gaits: a forward and a turning gait, which both emphasize speed for the robot; and a forward and turning gait which emphasize traction. We also report a comparative study of the performance of prototype robot designed using these concepts to other published snake-inspired robot designs.

Design and Analysis of a Miniature Modular Inchworm Robot

“…The Maryland Snake Inspired Robot [14] consisted of 3-DOF joint modules each with 2 revolute joints, that rotated in orthogonal planes with respect to one another, and a prismatic joint. Joint modules were stacked serially with 90 degree offsets and a 1-DOF friction-anchor module was placed at either end of the robot to grip the environment.…”

“…However, because of the wasted time and energy spent on lifting and lowering the modules normal to the robots trajectory, this motion can result in low forward velocities and limited range. Additionally, the extra required energy necessitates a larger chassis for storing additional sources of energy and makes these robots less suitable for operation in confined spaces [14].…”

Analysis of rectilinear motion of a three-segment snake robot under action of dry friction

“…Thus taking relations (12) and (16), the functionḠ(v), which is a average sum of f i , also monotonically decreases inv and may have discontinuity points determined by inequalitȳ…”

“…We apply the averaging method to the first-order equation (12) under the assumption that 1, which means the maximum frictional force acting on each segment is rather small in comparison with the propelling force. Besides, due to the physical property of actuators, the average velocitȳ V ∈ U , and the set of U is bounded and open.…”

“…presented a snake-inspired robot utilizing an exaggerated rectilinear gait to locomote, which enables the robot to achieve a high speed linear motion [12]. This kind of gaits are realized by using friction force anchoring concept.…”