An integrated miniature fingertip sensor

This paper describes an integrated fingertip for robotic (and even prosthetic) hands, which incorporates different types of sensors as well as signal preprocessing electronics. The core of the fingertip is an army of 64 piezoresistive sensors arranged in space-variant geometry as a high-resolution tactile "focus of attention". The space resolution of the sensor is 1 mm in the center and 4 mm in the periphery, whereas the force sensing range is comprised between 0.1 and 8 N, with a bandwidth of 100 Hz. A piezoelectric dynamic sensor is also included in the fingertip, providing sensitivity to vibrations during the exploration of object surfaces or in the event of slippage. The bandwidth of this sensor after processing exceeds 500 Hz. The fingertip incorporates a preprocessing circuitry implemented on two multilayer miniature boards based on SMD technology. The embedded processor is an 8-bit microcontroller and a parallel port provides PC-compatible I/O to the controller of the hand on which the fingertip is expected to be mounted. The integrated fingertip may be a useful tool for investigating exploratory and manipulation tasks in robotics.