• Title, Summary, Keyword: Mass Estimation

Search Result 706, Processing Time 0.035 seconds

Mass estimation using time-frequency analysis (시간-주파수 기법을 이용한 금속파편 질량 추정)

  • Choi, Young-Chul;Park, Jin-Ho;Yoon, Doo-Byung;Park, Keun-Bae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.1129-1134
    • /
    • 2006
  • Mass estimation was derived as functions of acceleration magnitude and primary frequency. The conventional method of mass estimation used frequency data directly in the frequency domain. The signals that can be obtained sensor contained noise as well as impact signal. Therefore, how well we can detect the frequency data in noise directly determines the quality of mass estimation. To find exact frequency data, we used time-frequency analysis. The time frequency method are expected to be more useful than the conventional frequency domain analyses for the mass estimation problem on a plate type structure. Also it has been concluded that the smoothed WVD can give more reliable means than the other methodologies for the mass estimation in a noisy environment.

  • PDF

Loose-part Mass Estimation Using Time-frequency Analysis (시간-주파수 기법을 이용한 금속파편 질량 추정)

  • Park, Jin-Ho;Yoon, Doo-Byung;Park, Keun-Bae;Choi, Young-Chul
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.16 no.8
    • /
    • pp.872-878
    • /
    • 2006
  • Mass estimation was derived as functions of acceleration magnitude and primary frequency. The conventional method of mass estimation used frequency data directly in the frequency domain. The signals that can be obtained sensor contained noise as well as impact signal. Therefore, how well we can detect the frequency data in noise directly determines the quality of mass estimation. To find exact frequency data, we used time-frequency analysis. The time-frequency methods are expected to be more useful than the conventional frequency domain analyses for the mass estimation problem on a plate type structure. Also it has been concluded that the smoothed WVD can give more reliable means than the other methodologies for the mass estimation in a noisy environment.

Mass Estimation of a Permanent Magnet Linear Synchronous Motor by the Least-Squares Algorithm (선형 영구자석 동기전동기의 최소자승법을 적용한 질량 추정)

  • Lee, Jin-Woo
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.11 no.2
    • /
    • pp.159-163
    • /
    • 2006
  • In order to tune the speed controller in the linear servo applications an accurate information of a mover mass including a load mass is always required. This paper suggests the mass estimation method of a permanent magnet linear synchronous motor(PMLSM) 4y using the parameter estimation method of Least-Squares algorithm. First, the deterministic autoregressive moving average(DARMA) model of the mechanical dynamic system is derived. Then the application of the Least-Squares algorithm shows that the mass can be accurately estimated both in the simulation results and in the experimental results.

Estimation of Inlet Air Mass Flow for Air-Fuel Raito Control of Gaseous-Fuel Engines (기체연료 엔진에서 공연비제어를 위한 흡입공기량 추정)

  • 심한섭;이강윤;선우명호;송창섭
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.9 no.5
    • /
    • pp.131-139
    • /
    • 2001
  • Highly accurate control of the air-fuel ratio is important to reduce exhaust gas emissions of the gaseous-fuel engines. In order to achieve this purpose, inlet air mass flow must be measured exactly, and precise engine models are necessary to design engine control systems. In this paper, the effects of water vapor and gaseous fuel that change the air mass flow are studied. The effective air mass ratio is defined as the air mass flow divided by the mixture mass flow, and also it is applied to the estimation of the inlet air mass flow. The presence of the gaseous fuel and the water vapor in the mixture reduces the air partial pressure and the effective air mass ratio of the gaseous-fuel engines. The Experimental results for an LPG engine show that the estimation of the inlet ai mass flow based upon the effective air mass ratio is more accurate than that of the normal air mass flow.

  • PDF

Mass Estimation of a Permanent Magnet Linear Synchronous Motor by the Least-Squares Algorithm (선형 영구자석 동기전동기의 최소자승법을 적용한 질량 추정)

  • Lee, Jin-Woo
    • Proceedings of the KIPE Conference
    • /
    • /
    • pp.427-429
    • /
    • 2005
  • In order to tune the speed controller in the linear servo applications the accurate information of a mover mass including a load mass is always required. This paper suggests the mass estimation method of a permanent magnet linear synchronous motor(PMLSM) by using the parameter estimation method of Least-Squares algorithm. First, the deterministic autoregressive moving average(DARMA) model of the mechanical dynamic system is derived. The application of the Least-Squares algorithm shows that the mass can be accurately estimated both in the simulation results and in the experimental results.

  • PDF

Mass Estimation of a Permanent Magnet Linear Synchronous Motor Applied at the Vertical Axis (수직축 선형 영구자석 동기전동기의 질량 추정)

  • Lee, Jin-Woo;Ji, Jun-Keun;Mok, Hyung-Soo
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.13 no.6
    • /
    • pp.487-491
    • /
    • 2008
  • Tuning of the speed controller in the linear servo applications needs the accurate information of a mover mass including a load mass. Therefore this paper proposes the mass estimation method of a permanent magnet linear synchronous motor(PMLSM) applied at the vertical axis by using the recursive Least-Squares estimation algorithm. First, this paper derives the deterministic autoregressive moving average(DARMA) model of the mechanical dynamic system used at the vertical axis. The application of the Least-Squares algorithm to the derived DARMA model gives the mass estimation method. Matlab/Simulink-based simulation and experimental results show that the total mover mass of a PMLSM applied at the vertical axis can be accurately estimated at both no-load and load conditions.

An Engine Model of a Heavy-Duty Compressed Natural Gas Engine for Design of an Air-Fuel Ratio Controller (대형천연가스차량의 공연비제어기 설계를 위한 엔진모델)

  • 심한섭;이태연
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.12 no.5
    • /
    • pp.80-87
    • /
    • 2003
  • Air partial pressure ratio and inlet air mass flow are influenced by water vapor and gaseous fuel in mixture on Compressed Natural Gas (CNG) engines. In this paper, the effects of the water vapor and the gaseous fuel that change the air mass flow and the air-fuel ratio are studied. Effective air mass ratio is defined as the air mass flow divided by mixture mass flow, and also it is applied to the estimation of the inlet air mass flow and the air-fuel ratio. The presence of the gaseous fuel and the water vapor in the mixture reduces the air partial pressure and the effective air mass ratio of the CNG engines. The experimental results for the CNG engine show that estimation of the air-fuel ratio based upon the effective air mass ratio is more accurate than that of a normal mode.

Mass-estimation Algorithm by Vibration Response Measurement of Dynamic Balance (동적 저울의 진동응답 측정에 의한 질량 추정 알고리즘)

  • 김병삼
    • The Journal of the Acoustical Society of Korea
    • /
    • v.19 no.5
    • /
    • pp.71-78
    • /
    • 2000
  • Quickness and precision are the two most important requirements for an industrial scale used in production lines. In this paper, a new approach, "Mass-estimation algorithm by vibration-response measurement of dynamic balance", is presented to improve some of drawbacks in conventional scales. The system, consisted of velocity and displacement sensors, spring scale, analog-digital converter and microcomputer, is based on full utilization of dynamic mass measurement of velocity and displacement via microcomputer-assisted real time monitoring. The resulting system, when combined with appropriate mass estimation algorithm software, has shown its effectiveness in terms of two desirable characteristics required.

  • PDF

Markov chain-based mass estimation method for loose part monitoring system and its performance

  • Shin, Sung-Hwan;Park, Jin-Ho;Yoon, Doo-Byung;Han, Soon-Woo;Kang, To
    • Nuclear Engineering and Technology
    • /
    • v.49 no.7
    • /
    • pp.1555-1562
    • /
    • 2017
  • A loose part monitoring system is used to identify unexpected loose parts in a nuclear reactor vessel or steam generator. It is still necessary for the mass estimation of loose parts, one function of a loose part monitoring system, to develop a new method due to the high estimation error of conventional methods such as Hertz's impact theory and the frequency ratio method. The purpose of this study is to propose a mass estimation method using a Markov decision process and compare its performance with a method using an artificial neural network model proposed in a previous study. First, how to extract feature vectors using discrete cosine transform was explained. Second, Markov chains were designed with codebooks obtained from the feature vector. A 1/8-scaled mockup of the reactor vessel for OPR1000 was employed, and all used signals were obtained by impacting its surface with several solid spherical masses. Next, the performance of mass estimation by the proposed Markov model was compared with that of the artificial neural network model. Finally, it was investigated that the proposed Markov model had matching error below 20% in mass estimation. That was a similar performance to the method using an artificial neural network model and considerably improved in comparison with the conventional methods.

Model-based localization and mass-estimation methodology of metallic loose parts

  • Moon, Seongin;Han, Seongjin;Kang, To;Han, Soonwoo;Kim, Munsung
    • Nuclear Engineering and Technology
    • /
    • v.52 no.4
    • /
    • pp.846-855
    • /
    • 2020
  • A loose part monitoring system is used to detect unexpected loose parts in a reactor coolant system in a nuclear power plant. It is still necessary to develop a new methodology for the localization and mass estimation of loose parts owing to the high estimation error of conventional methods. In addition, model-based diagnostics recently emphasized the importance of a model describing the behavior of a mechanical system or component. The purpose of this study is to propose a new localization and mass-estimation method based on finite element analysis (FEA) and optimization technique. First, an FEA model to simulate the propagation behavior of the bending wave generated by a metal sphere impact is validated by performing an impact test and a corresponding FEA and optimization for a downsized steam-generator structure. Second, a novel methodology based on FEA and optimization technique was proposed to estimate the impact location and mass of a loose part at the same time. The usefulness of the methodology was then validated through a series of FEAs and some blind tests. A new feature vector, the cross-correlation function, was also proposed to predict the impact location and mass of a loose part, and its usefulness was then validated. It is expected that the proposed methodology can be utilized in model-based diagnostics for the estimation of impact parameters such as the mass, velocity, and impact location of a loose part. In addition, the FEA-based model can be used to optimize the sensor position to improve the collected data quality in the site of nuclear power plants.