オブザーバを用いた極限環境用外部漏れのない高速サーボ弁

概要

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In this study, a high-speed servo valve with no outer leakage is developed, which is used to drive flexible hydraulic actuators (FHA) in extreme environments. In the valve, multilayered PZT devices are used to drive a spool directly and quickly, and are connected to lever mechanisms to magnify the device motion. A bellows is also used to prevent outer leakage from the space between the spool and the sleeve. Employing a disturbance observer, the lack of system damping of the valve is improved by feeding back the estimated velocity of the spool ; the estimated disturbance is also fed back to eliminate effectively the hysteresis between input voltage and output displacement of the PZT devices. The sampling frequency of the observer is 10 kHz. As a result, excellent response of the servo valve is obtained, with the maximum spool displacement of 100μm and the frequency band width of about 300 Hz. It is ascertained that the control method is suitable for this type of servo valve.
1995-01-25