Soft Transistor Valve for Versatile and Fast Soft Vacuum Gripper

Vacuum grippers are popular for their simplicity, reliability, and strength. However, their rigidity limits them to grip only relatively flat objects. To design a soft vacuum gripper, leakage through a suction cup must be prevented if the suction cup is not in contact with the object. Various soft valves have been proposed that mimic the working principle of conventional rigid valves. Still, they have limitations, such as the inability to grip objects with various surface characteristics and slow gripping speed. In this letter, we propose a new soft valve for a versatile and fast soft vacuum gripper. The proposed valve is inspired by the working principle of the air fuse, and the feasibility of the mechanism has been experimentally confirmed. Two performance indices are proposed for the optimization of the proposed valve. Analytical models are proposed to predict the pressure conservation and operating time according to the geometric parameters of the proposed valve, and the validity of the model is experimentally confirmed. The performance of the proposed soft valve has been compared with the existing vacuum saving methods. Finally, a soft vacuum gripper with the proposed valves was fabricated to verify that the proposed valve can grip objects with various surface characteristics rapidly.