A Soft 3D-Printed Robotic Hand Actuated by Coiled SMA

Eric Deng,Yonas Tadesse

doi:10.3390/act10010006

Abstract

Robotic hands with unique designs, capabilities and applications have been presented in the literature focusing on sensing, actuation, control, powering and manufacturing, most of which are created by manual assembly process. However, due to advancements in additive manufacturing, new capabilities have replaced traditional methods of manufacturing. In this paper, we present a soft 3D-printed robotic hand actuated by custom-made coiled shape memory alloy (SMA) actuators. The hand uses additive manufacturing of flexible thermoplastic polyurethane (TPU) material, which allows flexing at the joint and hence eliminates the need for additional assembly. Here, we present the full characteristics of the robotic hand such as object grasping categorized by size and weight from the ARAT kit and others. The robotic hand is 425 mm in length, weighs 235 g and is able to operate at a frequency of 0.125 Hz without active cooling. It can grasp an object of 55–81 mm widths, weighing up to 133 g, while consuming an average power of 7.82 W. We also show the time domain response of our custom-made coiled SMA to different current inputs, and its corresponding force and displacement. The current design yields a lightweight and low cost artificial hand with significantly simplified manufacturing for applications in robotics and prosthetics.

Highlights

Publisher’s Note: MDPI stays neu-Robotic hands have been researched for many years due to the need of grasping and manipulating complex objects to perform assistive functions for humans
We demonstrated the first usage of 3Dprinted soft thermoplastic polyurethane (TPU) elastomer in combination with coiled shape memory alloy (SMA)
As shown in the experimental results and accompanying videos, the TPU hand is capable of carrying significant amounts of weight with relatively fast response flexion times

Summary

Introduction

Robotic hands have been researched for many years due to the need of grasping and manipulating complex objects to perform assistive functions for humans. Robotic hands are the key components of social robots and industrial manipulators. There are many challenges in the design and development of robotic hands, including selection of actuators, design, control and manufacturing methods. These design decisions are often related to the application where the hand is going to be used. Our objective in this work is to design and develop a robotic hand that has as many of the following properties and capabilities as possible: tral with regard to jurisdictional clai-

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Conclusion