• Title, Summary, Keyword: Error compensation

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Development and Experimental Verification of an Error Compensation Model for a Five-axis Machine Tool using an Error Matrix (오차행렬을 이용한 5축 공작기계의 오차보정모델 생성 및 실험적 검증)

  • Kweon, Sung Hwan;Lee, Dong Mok;Yang, Seung Han
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.5
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    • pp.507-512
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    • 2013
  • This paper proposes a new model to compensate for errors of a five-axis machine tool. A matrix with error components, that is, an error matrix, is separated from the error synthesis model of a five-axis machine tool. Based on the kinematics and inversion of the error matrix which can be obtained not by using a numerical method, an error compensation model is established and used to calculate compensation values of joint variables. The proposed compensation model does not need numerical methods to find the compensation values from the error compensation model, which includes nonlinear equations. An experiment using a double ball-bar is implemented to verify the proposed model.

A Method of Boresight Error Compensation for Missile Radome (유도탄용 레이돔 시선각 오차 보정 기법)

  • Kim, Gwang-Hee
    • Journal of the Korea Institute of Military Science and Technology
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    • v.8 no.3
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    • pp.56-63
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    • 2005
  • The radome boresight error degrades the microwave seeker ability and the missile guidance performance. It increases the miss distance, also. This paper propose a method of radome boresight error measurement and compensation. The compensation method consist of radome analysis and radome compensation. In the radome analysis stage, we can know that the electromagnetic characteristics distorted by radome. In the compensation stage, the look-up table is built and used for compensation. The test uses a FMS(Flight motion simulator) and adjusts the FMS setup error for more accuracy. The result shows that not using an elaborate radome measurement equipment, the radome boresight error is well compensated easily.

Analysis, Modeling and Compensation of Dynamic Imbalance Error for a Magnetically Suspended Sensitive Gyroscope

  • Xin, Chaojun;Cai, Yuanwen;Ren, Yuan;Fan, Yahong;Xu, Guofeng;Lei, Xu
    • Journal of Magnetics
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    • v.21 no.4
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    • pp.529-536
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    • 2016
  • Magnetically suspended sensitive gyroscopes (MSSGs) provide an interesting alternative for achieving precious attitude angular measurement. To effectively reduce the measurement error caused by dynamic imbalance, this paper proposes a novel compensation method based on analysis and modeling of the error for a MSSG. Firstly, the angular velocity measurement principle of the MSSG is described. Then the analytical model of dynamic imbalance error has been established by solving the complex coefficient differential dynamic equations of the rotor. The generation mechanism and changing regularity of the dynamic imbalance error have been revealed. Next, a compensation method is designed to compensate the dynamic imbalance error and improve the measurement accuracy of the MSSG. The common issues caused by dynamic imbalance can be effectively resolved by the proposed method in gyroscopes with a levitating rotor. Comparative simulation results before and after compensation have verified the effectiveness and superiority of the proposed compensation method.

RVDT Phase Error Compensation for Absolute Displacement Measurement (절대 변위 측정용 RVDT의 위상 오차 보상)

  • Shin Dong-Yun;Yang Yoon-Gi;Lee Chang-Su
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.7
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    • pp.658-665
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    • 2006
  • RVDT is a transducer that presents rotary phase angle according to the displacement of eccentric rotor such as press machine. However a study on the phase error of RVDT that affects precision is not enough. This paper analyzes RVDT phase error and obtains compensation curves with serial or parallel resistance through simulation. First, error compensation procedure that analyses errors due to the unbalance of reference inductances of each pole and uses parallel resistance as a compensation is proposed. Second, error compensation procedure due to the amplitude unbalance of the sensor driving currents is examined by serial compensation resistance. Experimentally, we got stable RVDT with phase error under $1^{\circ}$ by the proposed method.

Development of Calibration and Real-Time Compensation System for Total Measuring Accuracy in a Commercial CMM (상용 3차원 측정기의 전체 측정정밀도 교정 및 실시간 보정시스템)

  • 박희재;김종후
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.9
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    • pp.2358-2367
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    • 1994
  • This paper presents techniques for evaluation and compensation of total measuring errors in a commercial CMM. The probe errors as well as the machine geometric errors are assessed from probing of the mechanical artefacts such as shpere, step, and rings. For the error compensation, the integrated volumetric error equations are considered, including the probe error adn the machine geometric error. The error compensation is performed on the absolute scale coordinate system, in order to overcome the redundant degree of freedom in the CMM with multi-axis probe. A interface box and corresponding software driver are developed for data intercepting/correction between the machine controller and machine, thus the volumetric errors can be compensated in real time with minimum interference to the operating software and hardware of a commercial CMM. The developed system applied to a practical CMM installed on the shop floor, and demonstrated its performance.

Development of Computer Aided Measurement and Compensation System for Linear Pitch Error Correction in CNC Machine Tools Implementing a New Optimal Correction Algorithm (CNC 공작기계 선형피치오차의 최적 보정알고리즘을 구현하는 자동 측정 및 보정 시스템의 개발)

  • 이석원;박희재;주종남
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.1
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    • pp.69-77
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    • 1998
  • Linear displacement accuracy is one of the most important factors that determine machine tool accuracy The laser interferometer has been usually recommended for the measurement of linear displacement accuracy. In this paper, microcomputer aided measurement and compensation system has been developed for the pitch error in a CNC machine tool. For accurate pitch error calculation. the analysis code for the pitch error has been also implemented according to the international standards (ISO). The PC based automatic compensation system for the pitch error is also implemented. A new algorithm for calculating optimum value for pitch error compensation is proposed, minimizing the deviation at each target points. The development system has been applied to a practical CNC maching center and the performance has been demonstrated.

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Research into Head-body Thermal Bending for High-accuracy Thermal Error Compensation (고정도 열변위보정을 위한 주축대의 열적굽힘에 대한 연구)

  • Kim, Tae-Weon;Hah, Jae-Yong;Ko, Tae-Jo
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.1
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    • pp.56-64
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    • 2002
  • Machine tools are engineered to give high dimensional accuracy in machining operation. However, errors due to thermal effects degrade dimensional accuracy of machine tools considerably, and many machine tools are equipped with thermal error compensation function. In general, thermal errors can be generated in the angular directions as well as linear directions. Among them, thermal errors in the angular directions contribute a large amount of error components in the presence of offset distance as in the case of Abbe error. Because most of thermal error compensation function is based on a good correlation between temperature change and thermal deformation, angular thermal deformation is often to be the most difficult hurdle for enhancing compensation accuracy. In this regard, this paper investigates the effect of thermal bending to total thermal error and gives how to deal with thermally induced bending effects in thermal error compensation.

Compensation of Thermal Errors for the CNC Machine Tools (II) - Analysis of Error Compensation Algorithm for the PC-NC Controller - (CNC 공작기계의 열변형 오차 보정 (II) - PC-NC제어기용 오차보정 알고리즘 분석 -)

  • 이재종;최대봉;박현구
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.214-219
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    • 2001
  • One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric errors, thermally-induced errors, and the deterioration of the machine tools. Geometric and thermal errors of machine tools should be measured and compensated to manufacture high quality products. In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. In this study, the compensation device and temperature-based algorithm have been presented in order to compensate thermal error of machine tools under the real-time. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses, a designed spherical ball artifact, and five gap sensors. In order to compensate thermal characteristics under several operating conditions, experiments performed with five gap sensors and manufactured compensation device on the horizontal machining center.

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A study on the automatic compensation of machining error in NC turning (NC 선반가공에 있어서 가공오차의 자동 보정에 관한 연구)

  • 박천경;박동삼
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.6
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    • pp.1542-1551
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    • 1990
  • This paper shown how to measure the machining error in diameter of cylindrical workpiece and compensate the measured machining error in NC turning. Machining error is measured by the electric micrometer mounted on the tool post with the NC part program for probe location path analyzed. Correct NC part program for finish turning is automatically generated to compensate the measured machining error. These concepts have been effectively introduced to a newly developed software for error compensation. In turning experiments with the developed error compensation system, machining error was almost within the specified tolerance, which reveals the effectiveness of the developed system.

Algorithm of Thermal Error Compensation for the Line Center - System Interface - (CNC공작기계의 열변형 오차보정 (II) - 알고리즘 및 시스템 인터폐이스 중심 -)

  • 이재종;최대봉;박현구;류길상
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.417-422
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    • 2002
  • One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric errors, thermally-induced errors, and the deterioration of the machine tools. Geometric and thermal errors of machine tools should be measured and compensated to manufacture high quality products. In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. In this study, the compensation device and temperature-based algorithm have been implemented on the machining center in order to compensate thermal error of machine tools under the real-time. The thermal errors are predicted using the neural network and multi-regression modeling methods. In order to compensate thermal characteristics under several operating conditions, experiments performed with five gap sensors and manufactured compensation device on the horizontal machining center.

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