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.