An Accurate Force Regulation Mechanism for High-Speed Handling of Fragile Objects Using Pneumatic Grippers

Abstract

Controlling the gripping force on fragile objects has been a challenging task for industrial grippers. The solution often requires an electric gripper with embedded force sensors and control feedback. This approach is costly and leads to extra gripper complexity. To avoid damage while handling fragile objects, this paper presents a novel force regulation mechanism (FRM) to be installed on pneumatic grippers. Without using additional sensors and control, the FRM can passively produce an adjustable contact force between the gripper jaws and objects of various sizes. Together with pneumatic grippers that have a higher gripping speed, lower cost, and simpler structure, this approach offers a more attractive solution than the use of electric grippers. In this paper, the design and analysis of the FRM are presented. A prototype of the FRM is illustrated to demonstrate the effectiveness and accuracy of force regulation. This novel mechanism is expected to serve as a reliable alternative for fragile object manipulation. Note to Practitioners —Pneumatic grippers are popular due to their low cost and simple structure. However, it is difficult to control the gripping force to handle fragile objects without damage. The FRM has a small size and can be easily installed on pneumatic grippers to provide fast force regulation. The gripping force depends on axial preload of the FRM rather than air pressure of the gripper. Axial preload is passively regulated using a screw or spacer. No additional source of power or sensor is required. The FRM has a large force adjustment range and can grip objects of various sizes using the same force. Applications include the automation in electronics, food, agricultural, and medical industries.