• Title/Summary/Keyword: Rotating System

Search Result 76, Processing Time 0.119 seconds

A study on the computer simulation model of the closed rotating system about the closed system (폐쇄된 계의 닫힌 회전 운동에 대한 컴퓨터 씨뮬레이션 모델에 관한 연구)

  • Chung, Byung-Tae
    • Journal of the Korea Computer Industry Society
    • /
    • v.8 no.3
    • /
    • pp.181-186
    • /
    • 2007
  • The movement in the closed system's internal and external, consists of linear open motion and linear closed motion, as well as non-linear motion and non-linear closed motion. When the linear closed motion receives external forces such as friction, closed motion is activated. It explains that even closed rotating systems that are subjected to external forces such as friction becomes a confined rotating system. Through fluid experiments the closed rotating system and confined system's quantitative data was observed and closed rotating system was confirmed to formulate the computer simulation function model concerning closed motion and confined motion. A basic graphic configuration of the motion device is also introduced.

  • PDF

Fault Diagnosis of Rotating System Mass Unbalance Using Hidden Markov Model (HMM을 이용한 회전체 시스템의 질량편심 결함진단)

  • Ko, Jungmin;Choi, Chankyu;Kang, To;Han, Soonwoo;Park, Jinho;Yoo, Honghee
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.25 no.9
    • /
    • pp.637-643
    • /
    • 2015
  • In recent years, pattern recognition methods have been widely used by many researchers for fault diagnoses of mechanical systems. The soundness of a mechanical system can be checked by analyzing the variation of the system vibration characteristic along with a pattern recognition method. Recently, the hidden Markov model has been widely used as a pattern recognition method in various fields. In this paper, the hidden Markov model is employed for the fault diagnosis of the mass unbalance of a rotating system. Mass unbalance is one of the critical faults in the rotating system. A procedure to identity the location and size of the mass unbalance is proposed and the accuracy of the procedure is validated through experiment.

Linearity and Nonlinearity of Rotor System Analysis (로터 시스템 회전운동 선형 및 비선형성)

  • Yun, Seong-Ho;Ren, Li-Min
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2008.04a
    • /
    • pp.190-196
    • /
    • 2008
  • The dynamical rotor system is investigated through the derivation and formulations of the dynamic equation of the rotating system in terms of both inertial and fixed frame of the system as well as quaternion. The investigation is aimed at analyzing the dynamical rotating system precession speed. The resulting equations of motion consist of the consistent mass matrix and gyroscopic matrix. The formulation shows its features and difference between its linearity and nonlinearity.

  • PDF

Stability Analysis of a Rotating System Due to the Effect of Ball Bearing Waviness (Waviness가 있는 볼베어링으로 지지된 회전계의 안정성 해석)

  • 정성원;장건희
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2002.05a
    • /
    • pp.181-189
    • /
    • 2002
  • This research presents an analytical model to investigate the stability due to the ball bearing waviness in a rotating system supported by two ball bearings. The stiffness of a ball bearing changes periodically due to the waviness in the rolling elements as the rotor rotates, and it can be calculated by differentiating the nonlinear contact forces. The linearized equations of motion can be represented as a parametrically excited system in the form of Mathieu's equation, because the stiffness coefficients have time-varying components due to the waviness. Their solution can be assumed as a Fourier series expansion so that the equations of motion can be rewritten as the simultaneous algebraic equations with respect to the Fourier coefficients. Then, stability can be determined by solving the Hill's infinite determinant of these algebraic equations. The validity of this research is proved by comparing the stability chart with the time responses of the vibration model suggested by prior researches. This research shows that the waviness in the rolling elements of a ball bearing generates the time-varying component of the stiffness coefficient, whose frequency is called the frequency of the parametric excitation. It also shows that the instability takes place from the positions in which the ratio of the natural frequency to the frequency of the parametric excitation corresponds to i/2 (i= 1,2,3..).

  • PDF

TURBO TYPE AIR COMPRESSOR DESIGN FOR LOW VIBRATION LEVEL (저진동을 위한 터보형 공기압축기의 설계)

  • Kim, Myeong-Kuk;Jung, Yong-Soo;Park, No-gill
    • 유체기계공업학회:학술대회논문집
    • /
    • 1998.12a
    • /
    • pp.159-165
    • /
    • 1998
  • Bearing design of turbo type geared centrifugal air compressor for low vibration level has been studied. The Transfer Matrix Method was used in this paper to analyze the air-compressor consisting of impellers, multi-stage geared rotors, and oil-film hearings. We have to consider this air-compressor as multi-geared rotating system, because characteristics of rotor-bearing system are different from conventional characteristics of non-rotating system. From the view point of Rotordynamics, the stiffness and damping coefficient of oil-film bearing in case of compressor system are more sensitive than other design parameters such as shaft length, shaft diameter and the weight of impellers, etc. Therefore, the stiffness and damping coefficients on each bearing were considered as design parameters. As the result of this study, turbo type air compressor with low vibration level can be achieved.

  • PDF

Position-Synchronous Control of a Rotating System by Adding Disturbance Observer to Coupling Structure (커플링구조와 외란관측기를 결합한 회전시스템의 위치동기제어)

  • 변정환
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.20 no.3
    • /
    • pp.66-73
    • /
    • 2003
  • In this study, a methodology of synchronous control which can be applied to position synchronization of a two-axis rotating system is developed. Based on coupling structure, the synchronous control system is composed of disturbance observer, speed and synchronous controllers. The speed controller is designed to follows speed reference. The disturbance observer is designed to restrain synchronous error. In addition, the synchronous controller is designed for a viewpoint of accurate synchronization in lead compensation law. The effectiveness of the proposed method is verified through simulation.

Computer Simulation for Dynamic Analysis of Rigid Body Suspension System for Waching Machine (세탁기용 강제 현가시스템의 동특성 해석을 위한 전산 시뮬레이션)

  • 정경렬;이종범;임무생;윤종만
    • Journal of KSNVE
    • /
    • v.3 no.1
    • /
    • pp.65-75
    • /
    • 1993
  • In this study, we identify the structural dynamic characteristics of the rigid body suspension system of waching machine containing rotating system, and consider the methods for the reduction of noise and vibration due to the structural problems. The structural dynamic characteristics of the suspension system have been studied by the computer simulation, in which the commercial software package, "DYMES(Dynamics of Mechanical System)" is used. The behaviour of the supporter by the rotating system has been parametrically studied by computer simulation, and the force and torque which are transferred to the fixed body through the suspension bar also has been calculated. The possibility to decide the position and the stability of the rigid body suspension system for waching machine is demonstrated based on various simulation results.n results.

  • PDF