Integrating discrete force cells into multi-modal artificial skin

In this paper, we present a new version of our multi-modal artificial skin, building from hexagonal shaped, intelligent unit cells. Our focus lies on the design of a discrete normal force sensor cell and its integration next to existing sensors for pre-contact, vibration/motion and temperature. The new force cell is cheap and easy to manufacture, scalable in size and force range, and addresses common drawbacks like hysteresis, noise, robustness and bandwidth. We locally sample and pre-process signals at 2.5 kHz and transfer filtered data at 250 Hz, enabling signal to noise ratios above 50 dB. Our rigid unit cells are encapsulated into 3D printed elastomer molds - we now mix hard and soft materials in the epidermal skin layer, in order to support enhanced force sensing. We provide detailed experimental characterization of the new force sensing modality on a custom dynamic test bench.