A study on the optimum position and repeatability control of a pneumatic cylinder actuator using PLC and proximity sensors

摘要

This research developed a position control system of the pneumatic cylinder to minimize an error of displacement of the pneumatic cylinder system and to increase the repeatability of displacement. The maximum air pressure of the position control test was 5 kg/cm~2 and the displacement accuracy of a stroke was measured by using a dial gauge. The supply-and discharge-side of air pressure and the length of the stroke of the pneumatic cylinder were adjusted and set before experiment. The test of the position control of the pneumatic cylinder was carried out 50 times at each supply- and discharge-side air pressure of 2.5/3.5, 3.0/4.0, 3.5/4.5, and 4.0/5.0 kg/cm~2 and replicated three times. The accuracy of the displacement of the pneumatic cylinder stroke increased as the supply- and discharge-side of air pressure increased with the fixed stroke length of 133 mm. Also it increased as the stroke length increased with the fixed supply- and discharge-side of air pressure of the pneumatic cylinder as 3.5/4.5 kg/cm~2. The most accurate displacement of the pneumatic cylinder (i.e., standard deviation of 0.01 mm) was obtained with the supply-and discharge-side of air pressure of 4.0/5.0 kg/cm~2and the stroke length of 170 and 190 mm.