A Stretchable Tactile Sleeve for Reaching Into Cluttered Spaces

We present a highly conformable stretchable sensory skin made of soft components. The skin uses low pressure pneumatic taxels and stretchable channels to conduct pressure signals to off-board micro-electromechanical systems (MEMS) pressure sensors. The force sensing range captures down to 0.01 N and has a roll-off frequency of 102 Hz. Due to pressure equilibration, the signals are substantially unaffected as the channels stretch and flex over robot joints with up to 100% elongation. The design permits additional floating taxels which, though less insensitive to stretch, provide sensing of contacts across joints and gaps. With no conductive elements or rigid components, the skin is robust to impacts and withstands many cycles of stretch and immersion in water. We apply the skin to a robotic wrist with two intersecting axes and show that it has sufficient sensitivity and bandwidth to detect the onset of sliding as the robot contacts objects. We demonstrate the skin in object acquisition tasks in a constrained environment for which extraneous contacts are unavoidable.