Self-excited three-passage switching valve capable of generating traveling wave and reversing wave direction

Abstract In recent years, pneumatically driven soft robots have been studied extensively. Usually, these soft robots contain multiple air chambers, and continuous motion such as locomotion is generated by pressurizing them sequentially. However, long air tubes are required when driving a soft robot far from the air pressure source. Consequently, it takes a long time for the air pressure to reach the chamber, and the motion of the soft robot is delayed. In this paper, we propose a device that self-excitedly switches the airflow passage by supplying continuous airflow. The device had two inputs and three outputs. Pressurizing input 1 switched the airflow passage in sequence, whereas pressurizing input 2 reversed the switching order. Connecting this device to a soft robot enables the robot to be driven without using solenoid valves. We experimentally confirmed that this device could drive a soft robot. We also discuss adjusting the motion frequency, switching pressure, and duty ratio in order to apply this device to other soft robots.