Soft Sensors for Soft and Wearable Robots

Abstract

With a growing need for safer human-robot interactions and taking the human skin properties as biological inspiration, the technological field of soft sensors has grown considerably in the last few years. Conventional tactile sensors integrated on robot gripers are nowadays available in multiple formats. Nonetheless, most of the tasks performed by robots demand complex rotational movements. Sensors adaptable to their host can turn robotic devices into safer technology to interact with and are easier to integrate in wearable devices since they do not interfere with their mechanical performance. The ease of access to soft materials and fabrication methods of customized objects through 3D printing, allows the development of soft sensors with desired geometries using low cost and simple methods. This work addresses the development of two distinct soft sensors, with embedded liquid-metal microchannels, by casting a liquid elastomer into 3D printed molds engraved with micro-dimensioned features. The first type of stretchable sensor, was designed for strain-sensing and can be applied in multiple devices to give information about joint angles and posture of prosthetic hands. The second designed sensor is intended to detect contact forces during manipulation and assembly. This project is a good example of how a mix of multidisciplinary knowledge coming from materials engineering, electronics, and robotics can form the basis of engineering state-of-art devices which can contribute to the further study and development of artificial skins with multiple sensing capabilities.