Tactile hyperacuity for robotics

Hyperacuity is a general aspect of animal perception that exploits spatially overlapping sensory receptive fields to perceive at finer acuity than the sensor resolution. Following a recent demonstration of hyperacuity in robot touch, we present a detailed and systematic analysis of localization acuity for both a biomimetic fingertip and a region of tactile skin. We identify three key factors for hyperacuity: (i) the sensor is constructed with multiple overlapping, broad but sensitive receptive fields; (ii) the tactile perception method interpolates between receptors (taxels) to attain sub-taxel acuity; (iii) active perception ensures robustness to unknown initial contact location. All factors follow from active Bayesian perception applied to biomimetic tactile sensors based on a capacitive technology. In consequence, we attain extreme hyperacuity with a thirty-fold improvement of localization acuity (0.12mm) over sensor resolution (4mm). We envisage that these principles will enable cheap, high-acuity tactile sensors that are highly customizable to suit various applications in robot touch.