Development of Opto-Pneumatic On/Off Control Valve

An optical servo system is a new control system that can be used in hazardous environments. The purpose of our study is to develop such an optical control system. In a previous study, we had realized an optical control system that executed cart positioning using optical control signals instead of electric signals. We developed an optical servo valve in which the output pressure was proportional to input optical power. As a next step, we need to develop another type of optical valve in order to get higher pressure-gain. In this study, we propose and produce an optical on/off valve that consists of an optical on/off device and a fluid amplifier, and the structure, operating principle and fundamental characteristics of the valve are investigated. As the result, we obtain a higher output pressure of the tested valve compared with the previous one. And we propose the analytical model of the optical on/off device and identify the system parameters. We confirm their validity by comparing them with experimental results. And finally, we improve the dynamics of the device by using a feedback passage plate based on analytical results of the device.