Hydraulically Coupled Dielectric Elastomer Actuators for a Bioinspired Suction Cup.

Chi Zhang,Yuxi Ding,Qi Li,Kanghui Xu,Lei Liu,Pengfei Li,Zhonghong Dong

doi:10.3390/polym13203481

Abstract

Suction cups of cephalopods show a preeminent performance when absorbing irregular or flat objects. In this paper, an octopi-inspired suction cup, driven by hydraulically coupled dielectric elastomer actuators (HCDEAs), is proposed, which is considered to be controlled easily and have compact structure. To investigate the performance of suction cups, experiments have been conducted to clarify the effect of the pre-stretch ratio and chamber angle on suction forces. It could be seen that both factors have a complicated influence on suction forces, and the best performance obtained was a reasonable combination of the pre-stretch ratio and chamber angle. Here, we achieved a maximum suction force of 175 mN with λp = 1.2, α = 23° under a DC voltage of 3500 V. To enhance the capacity and adaptation of the suction cup, flat objects of various types of materials were introduced as targets. Experimental results displayed that for tested materials, including a dry/wet acrylic plate, CD, ceramic wafer, and aluminum plate, the suction cup showed outstanding performance of absorbing and lifting the target without any damage or scratch to them. Our research may serve as a guide to the optimal design and provide insights into the performance of the HCDEAs-actuated suction cup.

Highlights

In robotics, the ability of robots to grasp and manipulate fragile and irregular objects is of great concern, especially when the target is flat and easy to scratch
Inspired by protuberances in the suction cups of octopuses, Baik et al [7] designed an adhesive patch fully covered with micro suction cups by air trapped technology, which functioned well on human skin with hair and sweat
As a sub-category of electro-active polymers, dielectric elastomers (DEs) are considered as promising artificial muscles for their outstanding features, such as large strain, low cost, high energy efficiency and fast response [22,23,24,25], and thy have been applied in many fields, such as as biomimetic robots [26,27], energy harvesters [28,29] and various actuators [30,31,32], since they were first reported by Pelrine [18]

Summary

Introduction

The ability of robots to grasp and manipulate fragile and irregular objects is of great concern, especially when the target is flat and easy to scratch. Wang et al [16] employed magnetically sensitive materials to change the volume of a suction cup chamber, which achieved a fast-response adhesion and high energy efficiency, within a comparably compact size. As a sub-category of electro-active polymers, dielectric elastomers (DEs) are considered as promising artificial muscles for their outstanding features, such as large strain, low cost, high energy efficiency and fast response [22,23,24,25], and thy have been applied in many fields, such as as biomimetic robots [26,27], energy harvesters [28,29] and various actuators [30,31,32], since they were first reported by Pelrine [18].

Design of Prototype

Fabrication of the Suction Cup

Results