Mechanics of the Whole Skin Locomotion Mechanism Concentric Solid Tube Model: The Effects of Geometry and Friction on the Efficiency and Force Transmission Characteristics

Abstract

In this paper, the effects of cross-sectional geometry and friction on the mechanical advantage and efficiency of the whole skin locomotion (WSL) mechanism concentric solid tube (CST) model are presented. WSL is a novel locomotion mechanism for mobile robots, which is inspired by the motility mechanisms of single celled organisms that use cytoplasmic streaming to generate pseudopods for locomotion. It works by way of an elongated toroid which turns itself inside out in a single continuous motion, effectively generating the overall motion of the cytoplasmic streaming ectoplasmic tube in amoebae. WSL can be considered as a new class of mechanism that converts the expanding and contracting motion of rings to an everting motion of the body. A brief description of the WSL mechanism is presented first, followed by the mechanics of a single and multiple actuator rings over a CST showing the relationship between the input ring tension force and the output propulsion force for a quasi-static case. Then a study of the force transmission characteristics is presented by studying the effects of cross-section geometry and friction on the efficiency and mechanical advantage of a single actuator ring over a semicircular and composite cross section CST.

Toroidal skin drive for snake robot locomotion

“…Anhalt and Herron developed and patented the toroidal skin drive mechanism [20] which is the basis for this work. Ingram and Hong have since developed a mechanism similar in concept to the toroidal skin drive described in this paper [21] [22]. Their device is capable of traveling in a forward direction and maneuvering through small holes and can expand to nominal size.…”

A Bioinspired Soft Swallowing Gripper for Universal Adaptable Grasping

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The Development of an Incrementally Loaded Finite Element Model of the Whole Skin Locomotion Mechanism: Discovering the Relationship Between Its Shape and Motion

“…There are currently two methods being considered for this application. On a large scale, larger than .1[m], accordion like pneumatic rings embedded in the skin which expand and contract with changes in pressure can be utilized [2]. This method can deliver both the high strains and forces that would be necessary to generate motion in the WSL robot.…”

“…Note that the solid tube pictured has been replaced with fluid in current design iterations. [2] At this point though, we have no way to quantify this motion or the shape generated by the internal forces. Stated differently, the interactions between the skin, fluid, ground, and actuators are not well understood.…”

“…The ectoplasm outer skin at the end transforms back into the liquid form endoplasm at the rear. The net effect of this continuous ectoplasm-endoplasm transformation is the forward motion of the amoeba [2].…”