Geometric Gait Design for a Starfish‐Inspired Robot Using a Planar Discrete Elastic Rod Model

Abstract

A starfish‐inspired robotic platform consisting of multiple soft fluidic bending actuator arms arranged with radial symmetry about a rigid hub is described. Intrinsic properties of the soft actuators are estimated via computer vision for varying input fluid pressures. The dynamic motion of individual arms and the full robot are modeled using the planar discrete elastic rod (PDER) theory. Locomotion gaits (periodic shape changes) that result in translation in the plane, separately considering fixed or rotating anchors at the end of each arm, are derived. Gait efficiency is defined as the displacement magnitude divided by a measure of the input control effort over each gait cycle, including a cost for anchor attachment. Through numerical computation, optimally efficient gaits are found and the desired motion with a pneumatic hardware prototype is demonstrated.