超音波PWMバルブによる空気圧シリンダの位置および力制御 (第1報)

シミュレーションと実験による制御法の検討

抄録

Pneumatic cylinders are used in factories because of easy handling, and large power. But the usage manners of the pneumatic cylinders are in many cases, under ON-OFF control. The stop positions of pneumatic cylinder are fixed beforehand so there is no flexibility in positioning. In the case of positioning, mechanical stoppers are used, which cause a large impact force to the equipments. The reasons why the position and velocity feedback control is not realized in the pneumatic cylinder are the characteristics of air compressibility and the lack of high performance valves. Recently some closed loop control systems are developed, in pneumatic system using proportional valves or other fast response valves. But commonly their cost performance is not so good, and the system is rather complicated. In this report, a new positioning and force control method is proposed, which uses ultrasonic valves under PWM control. The ultrasonic valve is switched by ultrasonic sound produced electrically actuated vibrator, so it has simple structure and the cost is low. In this report the response time of the ultrasonic valve is estimated experimentally. A test experimental equipment of closed pneumatic positioning system is constructed. The measured response time of ultrasonic valve is about 40 ms. The total performance is estimated by numerical simulation and by some experimental results, under the restriction of the valve response time.