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
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