Augmenting curved robot surfaces with soft tactile skin

We present a novel, soft, tactile skin composed of a fabric-based, stretchable sensor technology based on the piezoresistive effect. Softness is achieved by a combination of a soft silicone padding covered by a skin of more durable, tearproof silicone with an imprinted surface pattern mimicking human glabrous skin, found e.g. in fingertips. Its very thin layer structure (starting from 2.5 mm) facilitates integration on existing robot surfaces, particularly on small and highly curved links. For example, we augmented our Shadow Dexterous Hand with 12 palm sensors, and 2 resp. 3 sensors in the middle resp. proximal phalanges of each finger. To demonstrate the usefulness and efficiency of the proposed sensor skin, we performed a challenging classification task distinguishing squeezed objects based on their varying stiffness.

I. Introduction

Augmenting robot hands and complete robot surfaces with a soft, tactile-sensitive skin is an active research topic promising many advantages for manipulation and safe human-robot interaction. Mimicking soft flesh using elastomer pulps increases compliance, friction, contact area, and thus also grasp stability and the amount of applicable wrenches [1]. Especially hyper elastic material can generate higher static friction [2]. A rather simply shaped end-effector [3] demonstrates the possibilities of form locking due to adaptability.