Two-Hand-Arm Manipulation Based on Tri-axial Tactile Data

Tactile sensing ability is important for social robots, which perform daily work instead of persons. The authors have developed a three-axis tactile sensor based on an optical measurement method. Since our optical three-axis tactile sensor can measure distributed tri-axial tactile data, a robot equipped with the tactile sensors can detect not only grasping force but also slippage from its hands. In this paper, the authors have two objectives: one of them is evaluation of the three-axis tactile sensor in actual robotic tasks; the other is to demonstrate effectiveness of tri-axial tactile data for motion control. To accomplish these objectives, the authors have developed a two-hand-arm robot equipped with three-axis tactile sensors. In the robot motion control, we implement a recurrent mechanism in which the next behavior is induced by the tactile data to make the robot accept intention embedded in the environment. Since this mechanism is based on the tactile data, it is easy to apply it to communication between the hand-arms to obtain the best timing for cooperative work. In a series of experiments, the two-hand-arm robot performed object transfer and assembling tasks. Experimental results show that this tri-axial tactile base programming works well because appropriate behavior is induced according to slippage direction.