Experimental and theoretical study of dynamic characteristics of Bernoulli gripper

The Bernoulli gripper, which is widely employed in automated production lines, is a pneumatic manipulator capable of noncontact suction and gripping. Previous studies of Bernoulli grippers have focussed on its steady state suction force. This study experimentally and theoretically investigates the dynamic characteristics of the Bernoulli gripper. In practical applications, the gripped workpiece is lifted by placing the gripper immediately above the workpiece and then supplying compressed air to the gripper. In our pick-up experiment, the workpiece started to oscillate vertically after lifting, and then, the oscillation amplitude decreased until the workpiece became stable. Based on this experimental observation, we propose a mass-spring-damper model in which the steady state suction force is considered a spring and the squeeze-film flow exerts an additional damping force. Furthermore, the effects of the initial gap height and outer diameter on the motion of the workpiece are individually investigated. It was found that a small initial gap height and a large diameter aids in reducing the oscillation amplitude. In addition, the mass-spring-damper model could accurately predict the motion of the workpiece despite changes in the initial gap height and outer diameter.