Pneumatic Soft Actuator Using Self-Excitation Based on Automatic-Jet-Switching-Structure

Pneumatic pressure is a widely used power source in soft actuators as it has advantages such as simplicity of design, structure, and driving principle. However, electromagnetic valves are used for controlling pneumatic pressure, and these tend to be large and heavy, thus reducing flexibility in the main body. In this study, we devised a mechanism that generates self-excited vibration via changes in the flow path by deforming the flexible structure. Because self-excited vibration induces pressure for a certain input, actuators can be driven without using a valve in vibrating applications, which simplifies the structure of the actuator. The proposed actuator operates based on this mechanism; it has a simple structure, and thus, it can be molded easily using a 3D printer. A theoretical model of the proposed actuator was constructed, and its operating frequency was obtained via simulation. Four types of prototypes were produced, and their experimental values were compared with the theoretical values. The results of the comparison confirmed that an actuator can be designed based on the target operating frequency.