Tactile integrated circuit sensor realized with a piezoelectric polymer

A two-dimensional, electrically-multiplexed tactile sensor was realized by coupling a piezoelectric polyvinylidene fluoride (PVDF) polymer film to a monolithic silicon integrated circuit (IC). The IC incorporates 64 sensor electrodes arranged in a symmetrical 8×8 matrix. Each electrode occupies a 400×400 μm square area, and they are separated from each other by 300 μm. A 40-μm thick piezoelectric PVDF polymer film was attached to the electrode array with a non-conductive urethane adhesive. The response of the tactile sensor is linear for loads spanning 0.8 to 135 grams-of-force (gmf) (0.008-1.35 Newtons (N)). The time required to electrically interrogate, measure, and record the response of the sensor´s set of 64 taxels is less than 50 ms, the hysteresis level is tolerable, and, for operation in the sensor´s linear range, taxel crosstalk is negligible. The historically persistent stability and response reproducibility limitations associated with piezoelectric-based tactile sensors have been resolved by implementing a pre-charge voltage bias technique to establish known pre- and post-load sensor responses. A rudimentary tactile object image measurement procedure has been devised to recognize the silhouette of a sharp edge, square, trapezoid, isosceles triangle, circle, toroid, slotted screw, and cross-slotted screw