Bio-compatible Piezoresistive Pressure Sensing Skin Sleeve for Millimetre-Scale Flexible Robots: Design, Manufacturing and Pitfalls

Safe interactions between humans and robots require the robotic arms and/or tools to recognize and react to the surrounding environment via pressure sensing. With small-scale surgical interventions in mind, we have developed a flexible skin with tens of pressure sensing elements, designed to cover a 5mm diameter tool. The prototype uses only biocompatible materials: soft silicones, carbon powder and metal wires. The material performance, sensing element design, manufacturing technology, and the readout electronics are described. Our prototype demonstrates the feasibility of using this technology in various intervention scenarios, from endoscopic navigation to tissue manipulation. We conclude by identifying research directions that maximise the potential of the proposed technology.