空気圧操作ピストンによる力の制御

抄録

A precise force control system is designed by using a pneumatic piston-cylinder, membrane type electro-pneumatic converter and microprocessor, and a favorable result is obtained. The pneumatic piston-cylinder has relatively large frictional force and its irregularity even if the stroke is short. Then a closed loop control circuit with microprocessor so called software servo-system are employed to eliminate the affection. To obtain a higher accuracy in operating force, the effect of PD and PI controls are examined with a simple feedback system.
A favorable result is obtained by changing the sensitivity of integral action with the change of error. The level of reproducibility in controlled force is obtainable better than 0.095% of desired value 20.3N in standard deviation. The settling time can be reduced by changing control mode. At the start, derivative action is added to proportional action, but PI combination is supposed to be best for the settling and to reduce the difference between desired value and set value. The stability of the control system is assured by Hurwitz's criterion and experiment.