Abstract
The high accuracy position servo system of pneumatic cylinder is already reported by using a diaphragm-type electro-pneumatic converter. In this paper, a novel simple high accuracy position servo system are shown by using high response solenoid valves. The actuating part consists only of two valves and a cylinder. The valves open or close by a pulsating signal and charge the air to the cylinder or discharge from the cylinder directly. The pulse time duration and interval change with position of piston and this is not same as the conventional PWM method. To realize high accuracy piston displacement, the interval becomes as short as 0.005 s when the piston approaches near by the desired point.
The characteristics of this servo system are given by using a system model, and the relationship between stability of the piston displacement and valve opening duration can be shown theoretically. The single rod-type cylinder with 40 mm bore and 100 mm stroke is tested experimentally. As a result of repeated positioning test, it was shown that the piston keeps moving slightly at the desired point but it is able to position within 0.01 mm to the point.
