A new type of tactile sensor detecting contact force and hardness of an object

We propose a new type of tactile sensor that can detect both the contact-force and hardness of an object. It consists of a diaphragm with a mesa structure, a piezo-resistive displacement sensor on the diaphragm, and a chamber for pneumatical actuation. An array of these sensors can detect two-dimensional contact-force-distribution and hardness-distribution information, and the surface texture of the contacted object. We theoretically analyzed the operation of the tactile sensor, and designed its specifications for a device for detecting the touch of a human finger. We fabricated the device´s sensor element by micromachining technologies to prove the principle. The size is 3.0 mm /spl times/ 3.0 mm /spl times/ 0.4 mm, and it has a piezo-resistive displacement sensor element at the periphery of the diaphragm structure.