Development of soft and distributed tactile sensors and the application to a humanoid robot

This paper describes soft and distributed tactile sensors which give contact information to humanoid robots. In this paper, two types of tactile sensor element are proposed: one is a multi-valued touch sensor which has multi-level pressure thresholds. It is capable of covering wide areas of robot surfaces. The driving circuit is made as a module and scans the 128 switch elements which have two pressure thresholds in 1[ms]. The first pressure threshold is set to 25[gf/cm/sup 2/]. The other sensor is made of conductive gel which has remarkable softness. This conductive gel has the advantage of its softness compared with other sheet type tactile sensors. The impedance of the gel changes by approximately 20% from 0 to 400 [gf/cm/sup 2/]. The tactile sensor consists of 8/spl times/8 sensing points on the intersection of the electrodes, and the processing module scans all the points in 30[ms]. We apply them to a wheeled humanoid robot referred to as "H4". The detail of the sensor system on the robot and some experiments on the robot using tactile information are shown.