Abstract
When a robot grasps an object, posture errors between the hand and the object has a major influence on grasp success. So we have proposed to correct it before touching with Net-Structure Proximity Sensor (NSPS). This sensor can detect posture errors and distance to the object within tens of millimeters from the sensor. The sensor has characteristics of fast response (<1 [ms]), simple wiring (only 6 wires), and easy implementation. In this paper, we demonstrate simultaneous control of posture errors and distance of the fingertip before grasping. In order to archive this motion, we use a fingertip equipped with the proximity detector array, which can detect fingertip-object distance and postures simultaneously. Through this preparatory motion (called “pre-grasp”), it is possible to adjust fingertip position to vertical from the object surface. The robot hand can adjust fingertip postures for objects of various shapes automatically. So number of programs corresponding to shapes are not necessary. And it is also suitable for grasping of a fragile object, because it is kept low pressure of the object surface.
