Multi-modal Sensing Soft End-Effector for Underwater Applications Volume 3 - Issue 3

Liam B Cross, Rafsan Al Shafatul Islam Subad and Kihan Park*

• Department of Mechanical Engineering, University of Massachusetts Dartmouth, USA

Received: December 24, 2021   Published: January 6, 2022

Corresponding author: Kihan Park, Department of Mechanical Engineering, University of Massachusetts Dartmouth, Dartmouth, MA02747, USA

DOI: 10.32474/ARME.2022.03.000166

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Abstract

The underwater domain of soft robotic end-effector development is an emerging field that calls for advancements to multimodal sensing solutions in order to achieve a wide fluctuation of conformable object manipulation. In this paper, the design of a 3-digit end-effector capable of 6 degrees of shape sensing and 12 points of force sensing is proposed. Integral to the end-effector’s design is the presentation of its waterproofed soft-robotic actuators, each capable of 2-point shape sensing and 4-point force sensing. The individual actuator is designed as a uni-directional, bellow-type, PneuNet actuator built from silicone material. Onboard sensors utilize widely available piezo-resistive components which allow the actuator to act as a low-cost entry to shape sensing and force sensing. Each actuator exhibits a 2-part compound radius flex-sensor array and a 4-part single-point force sensor array. Of unique design is the bellow-type actuator’s custom chamber layout which gives it the ability to resemble approximated closed curvature of a human pointer finger. A technique for shape reconstruction is presented that estimates the shape of the soft actuator based upon embedded flex sensor measurements. The actuator is interrogated under transient pressure range to examine its grasp performance, shape sensing, and force measuring capabilities. The actuator is tested as a stand-alone unit, tested in tandem with a secondary unit, and also equipped with the proposed 3-digit end-effector. Each actuator and servo motor are subjected to an underwater ground-fault test to examine preliminary electrical integrity when submerged below surface level water, whereas visual inspection of a single 3-digit grasp is performed on a cylindrical object under surface level water. The overall goal of this work is to exhibit a tangible design solution for waterproofed multi-modal sensing within the soft robotic design frame for various underwater robotic applications.

Keywords: Soft Robotics; Three-finger Gripper; Low-cost Shape Sensing; Multi-modal Sensing; Underwater Applications

Abstract| Introduction| Materials and Methods| Results and Discussions| Conclusions| References|