A Gripper for Object Search and Grasp Through Proximity Sensing

Robots need to adapt themselves to various surroundings in order to achieve robust object search and grasp in unknown environments. For this adaptation, robot motions should be implemented as combination of primitive motions which are based on sensor reaction. Among various sensing methods, non contact sensing is required as a means of preventing operation failures such as pushing objects. Especially, proximity sensors have been proved effective in avoiding occlusion problems. In this paper, we first develop a gripper on which proximity sensors are mounted all around, and then calculate distance between the gripper and objects using proposed calibration method. This enables robots to recognize detailed shapes of objects surrounding the gripper. We also propose primitive motions for object search and grasp, and describe the contents of each motion. The motions are based on sensor information obtained from the gripper. We verify the effectiveness of our system through an experiment in which a real robot performs complex tasks by combination of the primitive motions.