Introduction
Despite the recent advancements in soft actuators and robots, integrating electronic functionalities into soft robotic systems remains a challenge. Particularly, a direct combination of conventional, rigid electronic components such as copper wires and soft robotic parts poses numerous problems with structural integrity and stability. This is because the mechanical property mismatch between the rigid electronic components and soft body generates points of stress concentration at the interface that typically becomes initiation points for failure during operations. Among possible solutions, developing soft conductors with comparable mechanical property to the soft robotic body seems to be a promising direction of development. However, although several types of inherently stretchable conductors have been developed for various sensors and electronic applications, functional incorporation of such materials into soft robotic systems tends to be tough. In this project, we present a two-step fabrication process that comprises of 3D printing a soft electronic circuitry on a soft base followed by an assembly with a molded soft robotic body. We demonstrate that the proposed approach can successfully fabricate a soft robotic hand with embedded soft electronic circuits, which can also light LEDs.
This project was performed by Pelkins Ajanoh and Jane Im. Pelkins majors in mechanical engineering at MIT, while Jane majors in computer science at Korea University, and is currently a special student at MIT. The team was supervised by Hyunwoo Yuk, a research assistant at MIT SAMs Lab.
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Objectives
The project’s objective is to demonstrate a facile method of embedding printable electronics into a pneumatically actuated soft robotic hand. In addition, the project aims to present a two-step fabrication process comprising of a combination of conventional mold-based fabrication of the soft robotic body and 3D printing of soft electronic circuitry.
We will describe the fabrication approach of molding and 3D printing in a step-by-step manner. We will also discuss the rationale behind the choice of conductive ink, and preparation of the soft electronic circuit. We will further demonstrate the design process and implementation of our proposed fabrication tactics for the miniature soft robotic hand, capable of accurately controlled gripping and flexing motion. The hand will have an embedded LED lighting circuit that will illustrate how the conductive material can be used.
We hope that the proposed method in this project will serve as a guide for those interested in embedding electronics in soft robots as well as those interested in exploring different fabrication methods like molding and 3-D printing in soft robotics.