Analytical model of conductive graphite foam based sensors characteristics
Sensors play an important role in the control systems, because they provide the necessary information from surroundings to the controller of an automated systems. Today’s sensors are very sophisticated, with high accuracy, fast acquisition rate and good signal-to-noise ratio. But most of these sensors are too much expensive. Low cost sensor for measuring the force (pressure) or the displacement could be realized by utilizing conductive elastomer that exhibits property of changing the electrical resistance when the elastomer is deformed. This paper introduced a novel conductive graphite foam based sensors. The sensors are formed by inserting two thin copper wires within conductive foam, parallel to each other at the two opposite sides. The main problem of conductive foam based sensors is that the force-electrical resistance characteristic, or the displacement-electrical resistance characteristic, of conductive foam is highly nonlinear. This paper presents the analytical model of the conductive graphite foam sensors for measurement of the displacement. By measuring the changes in the electric resistance between two points of the foam and using the developed analytical model it should be possible to accurately estimate the displacement when the conductive foam is deformed.