A Soft Sensorized Foot Module to Understand Anisotropic Terrains during Soft Robot Locomotion

The ability to move on an unstructured terrain and in confined spaces greatly increases the number of tasks terrestrial robots can carry out. To achieve this goal, robots should be aware of the different terrains on which they are moving. Here we present a soft sensorized foot module that can be used to better understand the interactions between the foot and the surfaces. The foot module detects force with repeatable and reliable information on flat, unstructured, and inclined surfaces. By characterizing the foot, we investigated the force interaction between the foot and the variable surface in three different conditions: i) normal loading on flat surface, ii) normal loading with obstacles (unstructured surface), and iii) tangential force. We further validated the measured forces applied by the soft foot module during a locomotion task performed both on flat and inclined surfaces. This study provides a better understanding of the interactions between the foot and the terrain and opens up to new way to design soft robots able to locomote on unstructured terrains.