Measuring information transfer in a soft robotic arm

TL;DR

This paper introduces an information-theoretic method to quantify and visualize how actuation effects propagate through a soft robotic arm, capturing delays and dynamics to better understand soft body behaviors.

Contribution

It extends momentary information transfer measures to soft robotics, enabling quantitative analysis of delayed actuation propagation and local information dynamics in soft bodies.

Findings

Successfully characterizes delayed actuation propagation

Visualizes information transfer through the soft body

Demonstrates applicability on an octopus-inspired robot

Abstract

Soft robots can exhibit diverse behaviors with simple types of actuation by partially outsourcing control to the morphological and material properties of their soft bodies, which is made possible by the tight coupling between control, body, and environment. In this paper, we present a method that will quantitatively characterize these diverse spatiotemporal dynamics of a soft body based on the information-theoretic approach. In particular, soft bodies have the ability to propagate the effect of actuation through the entire body, with a certain time delay, due to their elasticity. Our goal is to capture this delayed interaction in a quantitative manner based on a measure called momentary information transfer. We extend this measure to soft robotic applications and demonstrate its power using a physical soft robotic platform inspired by the octopus. Our approach is illustrated in two ways. First, we statistically characterize the delayed actuation propagation through the body as a strength of information transfer. Second, we capture this information propagation directly as local information dynamics. As a result, we show that our approach can successfully characterize the spatiotemporal dynamics of the soft robotic platform, explicitly visualizing how information transfers through the entire body with delays. Further extension scenarios of our approach are discussed for soft robotic applications in general.