Object Manipulation Using a Robotic Hand with an Active Ball at the Fingertip

–Application to Apple Picking–

Abstract

This paper proposes a 3-finger robot hand with an active ball at each fingertip, which is capable of bin picking and in-hand manipulation. The active ball is a rubber-coated steel ball, which is rotated by two motors located orthogonally. Appropriate rotations of the three balls enable a grasped object to rotate in all directions. A parallel link mechanism is adopted for picking objects while avoiding contact the fingers with surrounding objects; a vacuum type is adopted for picking up the objects; image processing is used for detecting the feature point. We demonstrate the apple shipping process to verify the feasibility. Experimental results show that the hand was capable of picking an apple even if it was located at the corner and that the active balls rotated the apple to orient the stem upwards using image processing.