Optopneumatic Interface for Controlling Pneumatic Power Circuits
Guido Belforte and Gabriella Eula
Department of Mechanics, Politecnico di Torino, C.so Duca degli Abruzzi, 24 - 10129 Torino - Italy
This paper presents a study of an optopneumatic interface integrated with a pressure amplifier stage. The interface works using photothermicity to generate a weak pressure signal in its control chambers. In photothermicity, infrared light strikes a black body a few microns thick, increasing the temperature of the black body and air close to it. If this air is in the control chamber of the optopneumatic interface, its expansion generates a pressure control signal, amplified to make it suitable for common low/high commercial pressure valves. This control enables the command of pneumatic actuators in hazardous environments, with the electrical signal transformed into optical and transported using optical fiber; all electrical parts can be located at a distance from direct application. Our results showed that the device’s response times, accuracy, and repeatability are suited to many applications. Below is an example of a command integrating electric, optical, and pneumatic techniques and operating by an infrared source with very low light power.