自励振動法による電油サーボ弁の線形近似伝達関数の同定

第1報 流量検出遅れが無視できる自励振動系の場合

抄録

This paper shows a simple method to identify the approximate transfer function of an instrument as a standard 2nd order delay system, and illustrates its application for an electro-hydraulic servo-valve. It is shown that the dynamic performance parameters, i.e., the damping ratio ζ_υand undamped natural frequency ω_nυ of the electro-hydraulic servo-valve can be identified by analyzing the self-excited oscillation waves in the bang-bang integrated flow-rate control system.
The experimental setup of the self-excited vibration system consists of an electro-hydraulic servo-valve, a flow-rate sensing system, an integrator and nonlinear electro-circuit. The dynamic performance parameters ζ_υ ω_nυ of the electro-hydraulic servo-valve under general operational conditions are obtained by means of the self-excited vibration system, and in addition, the frequency responses of the hydraulic servo-valve are measured. Then, the frequency characteristics of the identified transfer function and of the measured data are compared to confirm the coincidence of both characteristics within the band width where the phase angle of frequency response becomes -75--90°.