서지주요정보
외부 가압 공기 베어링의 능동 제어에 관한 연구 = A study on active control of externally pressurized air bearings
서명 / 저자 외부 가압 공기 베어링의 능동 제어에 관한 연구 = A study on active control of externally pressurized air bearings / 이정배.
저자명 이정배 ; Lee, Jeong-Bae
발행사항 [대전 : 한국과학기술원, 1998].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8008320

소장위치/청구기호

학술문화관(문화관) 보존서고

DME 98024

휴대폰 전송

도서상태

이용가능

대출가능

반납예정일

리뷰정보

초록정보

Externally pressurized air journal bearing has been widely used in high-speed spindle system and precision machinery because of its characteristics such as substantially low frictional loss, low heat generation and averaging effect leading better running accuracy. But, like other fluid film bearings, air journal bearing has self-excited instability which is commonly called "whirl instability". Journal speed at the onset of this instability is the limit speed of journal operation. So, to increase the operation speed of spindle, which is supported by air journal bearing, suppression of the whirl instability is a very important subject. In this thesis, active control of bearing is proposed as a stabilization method of air journal bearing and results of theoretical and experimental investigations of the characteristics of actively controlled externally pressurized air journal bearing are presented. Linearized perturbation method, step jump method and nonlinear orbit method are selectively used to obtain the stability characteristics of active air journal bearings operating at zero steady-state eccentricity. Proportional-derivative control and synchronous control are used for the control algorithm of active air bearing. In proportional-derivative control, the speed at onset of instability is raised for both proportional and derivative control of bearing. Proportional control increased the stability threshold without affecting the whirl ratio. But in the case of derivative control, stability threshold increase is accompanied by a parallel reduction of the whirl ratio. For synchronous control of bearing, the stability of air bearing is greatly influenced by phase difference of bearing with respect to the rotor, there exists optimum phase difference which gives maximum stability threshold. The whirl ratio also influenced by the synchronous control of bearing. With respect to the running accuracy, actively controlled air bearing is investigated to overcome the defects of air bearing such as low stiffness and damping coefficients. Active thrust bearing and active journal bearing are designed and manufactured. The active air bearings are composed with air bearings, gap sensors, a controller, and piezo actuators. Proportional-Integral-Derivative controller is employed. Active air bearing is investigated numerically and experimentally. There is good agreement between the simulation and the experimental results. These results show that active control of bearing can be adopted for the stability improvement method of air journal bearing, also the stiffness and damping characteristics and positioning accuracy of air bearing can be improved by means of active control of bearing.

서지기타정보

서지기타정보
청구기호 {DME 98024
형태사항 xvii, 144 p. : 삽도 ; 26 cm
언어 한국어
일반주기 저자명의 영문표기 : Jeong-Bae Lee
지도교수의 한글표기 : 김경웅
지도교수의 영문표기 : Kyung-Woong Kim
학위논문 학위논문(박사) - 한국과학기술원 : 기계공학과,
서지주기 참고문헌 : p. 142-144
주제 능동 제어
훨 불안정성
안정 한계
위상
게인
Active control
Whirl instability
Whirl ratio
Phase
Gain
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