Inertia-Enhancement Effect Of Divergent Flow On The Force Characteristics Of A Bernoulli Gripper

Bernoulli grippers, which are widely employed in automated production lines, are pneumatic manipulators capable of noncontact adsorption that utilize the decelerating inertial effect of the radial air flow to generate negative pressure and a suction force. This paper proposes an innovative design for the Bernoulli grippers in which divergent flow is formed through a tiny-inclination cone structure between the gripper and the workpiece, and the inertia-enhancement effect of the divergent flow is exploited to greatly increase the negative pressure and suction force (hereafter, this is referred to as a divergent-flow gripper). First, a theoretical model of the divergent flow between the divergent-flow gripper and the workpiece was formulated. The theoretical formulas for calculating the pressure distribution and suction force were then derived. Suction force measurement experiments were then conducted, whose results indicated that the proposed divergent-flow gripper can increase the suction force by several factors compared with that of an unmodified gripper with a flat surface. The influence of the divergent flow on the inertial and viscous effects of the gripper was examined both theoretically and experimentally, and the main factors leading to the increase in suction force were analyzed. In addition, this paper discusses the influence of the inclination angle and diameter of the gripper. As a result, through changes in the geometric structure and velocity distribution, the proposed divergent-flow gripper has the advantages of a large suction force and simple structure, and these findings serve as important theoretical and experimental references for the design of the Bernoulli gripper.