Stretchable liquid tactile sensor for robot-joints

In this paper, we propose a stretchable tactile sensor composed of a pair of silicone rubber channels filled with electro conductive liquid. When a force was applied to this channel, its length and cross-sectional area deforms. By measuring the resistance change of the electro conductive liquid in the channel, its deformation can be measured. The proposed tactile sensor is composed of two parallel channel filled with electro conductive liquid, therefore, by comparing the resistance changes of each channel to the deformation, only the contacting force can be measured independently. Since a liquid is used for the sensing material, the proposed liquid tactile sensor can be easily attached to movable portions as the joints of robots. In the paper, we measured the sensing characteristics of the liquid tactile sensor to the stretch, bend, and contact force. Finally, the efficiency of the sensor was demonstrated by measuring the contact force from 0 to 3.0N by attaching the 20% stretched liquid tactile sensor to curved surfaces with 0.05mm^-1 in curvature.