• Title/Summary/Keyword: Test Error

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Developement of Measuring Units of circular Motion Accuracy on NC Lathe (NC선반의 원 운동정도 측정장치의 개발)

  • 김영석;김재열
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.10 no.6
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    • pp.1-7
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    • 2001
  • It is very important to test circular motion accuracy of NC machine tools as it affects all other machines machined by them in industries. In this paper, it has become possible to detect errors of linear displacement of radial directions for circle tar motion accuracy test using newly assembled magnetic type of linear scale so called Magnescale ball-bar system. It has also organized computer program systems using tick pulses come out from computer for getting error motion data at colt start time interval in circular motion test on NC lathe. Error data gotten from test is expressed to plots and analysed to numerics by various statistical treatments.

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Extension of Absolute Evaluation Technique for Ratio Error and Phase Displacement of Core Type Current Transformers: Ip =$5\;kA{\sim}40\;kA$ (철심형 전류변성기의 비오차 및 위상오차 절대 평가 기술의 확장 : 1차 전류 = $5\;kA{\sim}40\;kA$)

  • Kim, Yoon-Hyoung;Han, Sang-Gil;Jung, Jae-Kap;Han, Sang-Ok
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.57 no.4
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    • pp.431-436
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    • 2008
  • We have extended an absolute evaluation method to obtain the ratio error and phase displacement of a current transformer (CT) up to primary current of 40,000 A by measuring four parameters of equivalent circuit in CT. The method was applied to CTs under test with the current ratios in the range of 5,000 A / 5 A - 40,000 A / 5 A. The ratio error and phase displacement of the CTs under test obtained in this study are consistent with those measured at the national institutes in Canada and Germany using the same CTs under test within an expanded uncertainty (k = 2) in the overall current ratios.

GNSS Airborne Multipath Error Modeling Under UAV Platform and Operating Environment

  • Kim, Minchan;Kim, Kiwan;Lee, Dong-Kyeong;Lee, Jiyun
    • Journal of Positioning, Navigation, and Timing
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    • v.4 no.1
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    • pp.1-7
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    • 2015
  • In the case of an unmanned aerial vehicle (UAV) equipped with a GNSS sensor, a boundary line where the vehicle can actually exist can be calculated using a navigation error model, and safe navigation (e.g., precise landing and collision prevention) can be supported based on this boundary line. Therefore, for the safe operation of UAV, a model for the position error of UAV needs to be established in advance. In this study, the multipath error of a GNSS sensor installed at UAV was modeled through a flight test, and this was analyzed and compared with the error model of an existing manned aircraft. The flight test was conducted based on a scenario in which UAV performs hovering at an altitude of 40 m, and it was found that the multipath error value was well bound by the error model of an existing manned aircraft. This result indicates that the error model of an existing manned aircraft can be used in operation environments similar to the scenario for the flight test. Also, in this study, a scenario for the operation of multiple UAVs was considered, and the correlation between the multipath errors of the UAVs was analyzed. The result of the analysis showed that the correlation between the multipath errors of the UAVs was not large, indicating that the multipath errors of the UAVs cannot be canceled out.

Development of Displacement Measuring Sensor for Roll Eccentricity Contro1 at Hot Strip Mill (롤 편심제어를 위한 편심 측정장치 개발)

  • 전종학
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.167-167
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    • 2000
  • This study aims at the development of REC sensor causing the gauge error in the hot strip rolling process, and the improvement of the hydraulic AGC (Automatic Gauge Control) system. The gauge error outbreaks from the various reasons, however, mainly the roll eccentricity is considered to cause a such kind of error. In the study, the REC (Roll Eccentricity Control System) sensor is designed using sensor An On - line test of the system shows the comprehensive effects of controlling the gauge error of the hot strip. On - Line test shows the possibility of enhancing the accuracy for gauge.

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Tests of Factor Effect Using Saturated Design in $K^n$ Factorial Design ($K^n$ 요인배치법에서 포화실험에 의한 요인효과의 검정)

  • Choi, Sung-Woon
    • Proceedings of the Safety Management and Science Conference
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    • 2008.04a
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    • pp.295-299
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    • 2008
  • This paper discusses tests of factor effect or contrast by the use of saturated design $k^n$ factorial design. The nine nonparametric rank measures in normality test using normal probability pot are proposed. Length's PSE(Pseduo Standard Error) test [4] which relies on the concept of effect sparsity is also introduced and extended to the margin of error(ME) and Simultaneous margin of error(SME).

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Reliability of the redundant system with dependent human error (인간실수를 고려한 중복시스템의 신뢰도 분석)

  • 김명기;장순흥
    • Journal of the Ergonomics Society of Korea
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    • v.1 no.2
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    • pp.11-15
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    • 1982
  • There is the possibility that human error during testing and maintenance brings about the failure of the system, the reliability of which depends on mechanical failure and human error. This paper deals with the calculation of the reliability of the redundant system with the dependent hunman error through Karnaugh Map. Two cases are considered. One is the reli- ability of the system neglecting the test interval of each component and the other is that considering the test interval of each component.

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A Study on Comparison of the Characteristic Test of Discharge Water Flowmeters (Electromagnetic Flowmeter, Parshall Flume) (방류수 유량계(전자기유량계, 파샬플룸)의 특성평가 연구)

  • An, Yang-ki;Kim, Jee-young;Kim, Kum-hee;Jang, Hee-soo;Jung, Jung-pil;Choi, Jong-woo
    • The KSFM Journal of Fluid Machinery
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    • v.18 no.6
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    • pp.57-62
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    • 2015
  • The test of comparing liquid flow calibration system (approved by KOLAS) for accuracy and structure change test was performed in the test bed in order to evaluate the typical characteristics of the electromagnetic flow meters and parshall flume that are generally used in the water discharging facilities. The results of the accuracy comparing test with liquid flow calibration system showed the error of less than 2%. Pharshall plume got error up to -8.3% (low flow) from the flow rate test, but less than 4% from the accumulated flow test because of offset error at high flow rate and low flow rate. Evaluation of structual change test was tested with only parshall flume using structure and it consisted of installation angle (parshall flume and level sensor) and position change. Installation angle, water level sensor angle and position changing test for parshall flume had errors of 3.1%~-9.2%, 0.4%~-5.6% and 0.2%~1.3% respectively. Especially, the error showed the largest increase when the water level sensor measured the point of decreased flow by the structure change. Therefore, error factors (change of straight pipe length, installation of obstacle or effect of foreign substances on water level sensor) that can often occur in the field should be derived and the research for optimized installation method should be carried out continuously.

Experimental Study on Effects of Speed Error Disturbance on Reaction Wheel Control (속도 오차 외란이 반작용 휠 제어에 미치는 영향에 관한 실험적 연구)

  • Kim, Jichul;Lee, Hyungjun;Yoo, Jihoon;Oh, Hwasuk
    • Journal of Aerospace System Engineering
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    • v.10 no.1
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    • pp.95-102
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    • 2016
  • There are many possible disturbance sources on such a spacecraft, but reaction wheel assembly (RWA) which is generally used for spacecraft attitude control is anticipated to be the largest. These effects on degradation of performance of spacecraft such as attitude stability. In reaction wheel, disturbance caused by imbalance and speed error. It is hard to emulate speed error disturbance because it is not coincide with wheel frequency. This paper concentrates on emulating and analyzing the speed error disturbance. Firstly, classify the causes that lead to speed error disturbance which generate RPM fluctuation. Secondly, simulated with disturbance driver module and reaction wheel assembly which are developed by Spacecraft Control Lab. Experimental investigations have been carried out to test the disturbance emulator module as a disturbance generator for RWA. Measurements and test have been conducted on various fault. Frequency analysis of test data show that speed error disturbance effects on wheel settling wheel speed or fluctuation type.

Relationship between Normal Measurement and Error Rate of Output Voltage Linear Ratio of Seismic Accelerometer in Use (사용 중 지진 가속도계의 정상 측정과 출력전압 선형비 오차율 관계 분석)

  • Min-Jun Kim;Seong-Cheol Cho;Yong-Hun Jung;Jeong-Hun Won
    • Journal of the Korean Society of Safety
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    • v.39 no.2
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    • pp.65-74
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    • 2024
  • We analyzed the relationship between the normal measurement of the seismic accelerometer (SA) and the error rate of the output voltage linear ratio to propose an evaluation method to determine whether the SA in use is measuring normally. Utilizing a test bed, the regular operation of SA in use was evaluated using acceleration data measured through impact tests since there are no regulations regarding performance testing of SA in use. For the used SA, the error rate of the output voltage linear ratio, which is a major performance criterion, was evaluated. We analyzed common characteristics of the SA that satisfied the impact test and the performance criteria of the output voltage linear ratio error rate. The results indicated that we must consider the decreasing trend and convergence of the error rate as the measurement angle increases, ensuring that the average value of the output voltage linear ratio error rate is within 1%.

A Study on Teaching Method of One-Sample Test for Population Mean (일표본 모평균 검정의 지도에 관한 연구)

  • 김용택;이장택
    • The Mathematical Education
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    • v.42 no.3
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    • pp.419-423
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    • 2003
  • The main purpose of this paper is to investigate effects of skewness and kurtosis on the one-sample test. We have found that type I error brought about a little bit change which is ignorable in relation to kurtosis. Also the change of type I error was completely based on skewness under the same size of the sample. We conclude that using t-test is more similar to robust than using z-test. In introductory statistics classes where data analysis includes techniques for detecting skewness, we recommend the t-test when skewness is smaller than the value 1 to the one-sample test for a mean when the variances is unknown using the probability of a type I error as the criterion of interest.

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