Compliant Fins for Locomotion in Granular Media

TL;DR

This paper introduces an origami-inspired compliant fin mechanism for granular media locomotion, utilizing enhanced resistive force theory and simulation to optimize robot gait and demonstrate improved mobility in granular environments.

Contribution

It presents a novel compliant fin design with asymmetric gait control, combined with an extended resistive force theory and simulation framework for optimized granular propulsion.

Findings

Successful prototype demonstrating effective granular locomotion

Optimized fin design improves propulsion efficiency

Simulation-based gait optimization enhances robot performance

Abstract

In this paper, we present an approach to study the behavior of compliant plates in granular media and optimize the performance of a robot that utilizes this technique for mobility. From previous work and fundamental tests on thin plate force generation inside granular media, we introduce an origami-inspired mechanism with non-linear compliance in the joints that can be used in granular propulsion. This concept utilizes one-sided joint limits to create an asymmetric gait cycle that avoids more complicated alternatives often found in other swimming/digging robots. To analyze its locomotion as well as its shape and propulsive force, we utilize granular Resistive Force Theory (RFT) as a starting point. Adding compliance to this theory enables us to predict the time-based evolution of compliant plates when they are dragged and rotated. It also permits more rational design of swimming robots where fin design variables may be optimized against the characteristics of the granular medium. This is done using a Python-based dynamic simulation library to model the deformation of the plates and optimize aspects of the robot's gait. Finally, we prototype and test robot with a gait optimized using the modelling techniques mentioned above.