• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.101-106
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• 2004

Measurements of linear motion accuracy for one axis of NC lathe have achieved with laser interferometer system, but measurement of plane motion accuracy for two axes on zx-plane of NC lathe have not achieved with the above system. Therefore in this study, measuring unit system is organized using two optical linear scales in order to acquire error. data during of plane motion of ATC(Automatic Tool Change.) of NC lathe by reading zx-plane coordinates. Two optical linear scales of measuring unit are fixed on zx-plane of NC lathe, and moving part of the scales are fixed to the ATC and then error motion data of z, x-coordinates of the ATC are received from the scales through the PC counter card inserted in computer at constant time intervals using tick pulses coming out from computer. And then, error motion data files acquired from measuring are saved in computer memory and the aspect of plane motion are modeled to plots, and range of the error data, means. average deviations, and standard deviations etc. are calculated by means of statistical treatments using computer programs.

• Journal of KSNVE
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• v.8 no.6
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• pp.1023-1029
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• 1998

When one attempts to construct a hologram. one finds that there are many sources of measurement errors. These errors are even amplified if one predicts the pressures close to the sources. The pressure estimation errors depend on the following parameters: the measurement spacing on the hologram plane. the prediction spacing on the prediction plane. and the distance between the hologram and the prediction plane. This raper analyzes quantitatively the errors when these are distributed irregularly on the hologram plane The sensor mismatch and inaccurate measurement location. position mismatch. are mainly addressed. In these cases. one can assume that the measurement is a sample of many measurement events. The bias and random error are derived theoretically. Then the relationship between the random error amplification ratio and the parameters mentioned above is examined quantitatively in terms of energy.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.419-428
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• 2011

This paper suggests a judgement method for an inclined plane before entrance of it and the detection of obstacle position. Main idea is started from the assumption that obstacle is always on the bottom plane, and corner appears at this position. The process to detect the obstacle consists of three steps. First the 3D data using stereo matching is acquired to detect an obstacle. Second a bottom plane is extracted by using limit condition. Last the obstacle position is found by using Harris corner detection. Obstacle position detection on an inclined plane was verified by outdoor and indoor experiment. In error analysis, it is confirmed that an average error of obstacle detection in outdoor was larger than the error in indoor but the error are within about 0.030 m. This method will be applied to unmanned vehicles to navigate under various environment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.379-382
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• 2002

Among the CMM calibration techniques, the calibration with standard specimen is most accurate way to acquire the required precision. When there is no standard specimen, the calibration of CMM with itself is possible. This calibration method is called "self-calibration". In this paper, we developed self-calibration algorithm for CMM XY plane. It is possible to calculate the in-plane error and out-of-plane error of CMM with 3 different measurement of same artifact. Experimental result shows that the non-orthogonality error is dominant in in-plane error and the self-calibration result and laser interferometer measured result have almost same value.ame value.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.5
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• pp.664-675
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• 1998

The purpose of this study was to isolate the observational error included in plane photogrammetric data and suggest more accurate and suitable method for body shape measurement. Three experiments were carried out in this study. First of all, the variables which can be obtained from photogrammetric method were selected among the data which can be measured improperly by direct measurement or showing large deviations between the samples. Secondly, the height, the width and the depth of 50 subjects were measured by plane photogrammetry. The result showed that plane photogrammetric data contain significant observational error even for the same variables, as the angle of which photos had been taken changes. Therefore, in order to reduce the observational error and to measure the human body accurately, three-dimensional measurement, stereo photogrammetry was employed in the last experiment. As it is important to isolateonly the observational error by plane photogrammetry and to exclude the accidental error caused by movement of human body subject, body shape model(manikin) was used as subject. The result showed that the average observational error by plane photogrammetry was more than 4 cm in the height, 0.85-1.29cm in the width and 0.49cm in the depth. In conclusion, it is not adequate to use the height obtained from plane photogrammetric data as human body measurement data. And the width and the depth should be used cautiously, even though they are relatively less significant, the error still can make some difference on clothing construction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.108-108
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• 2003

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.8 no.2
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• pp.35-43
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• 1990

In this paper a two dimensional network adjustment theory is developed to analyze the plane trilateration network of single triangle network, of quadrilateral network, of polygon trilateration network and of combined network. The characteristics of error were analysed by developing an error propagation equation for each form of plane trilateration network. In case of combined network, the result of error analysis was represented by error ellipses and gross error detection was carried out by data snooping method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.1
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• pp.56-62
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• 1988

For shape description, a fast sequential method for polygonal approximation of chaincoded plane curves which are object boundaries is proposed. The proposed method performs polygonal approximation by use of the distance error from one point to a line, and its performance is enhanced by the smoothed slopes of lines. Furthermore, accumulated distance error and variable distance error threshold are proposed in order to consider and implement the visual characteristics of the human being.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1325-1328
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• 2007

When we visualize the sound field radiated from a spherical sound source, spherical acoustic holography is proper among acoustic holography methods. However, there are measurement errors due to sensor position mismatch, sensor mismatch, directivity of sensor, and background noise. These errors are amplified if one predicts the pressures close to the sources: backward prediction. The goal of this paper is to quantitatively examine the effects of the error due to sensor position mismatch on acoustic pressure estimation. This paper deals with the cases of which the measurement deviations are distributed irregularly on the hologram plane. In such cases, one can assume that the measurement is a sample of many measurement events, and the cause of the measurement error is white noise on the hologram plane. Then the bias and random error are derived mathematically. In the results, it is found that the random error is important in the backward prediction. The relationship between the random error amplification ratio and the measurement parameters is derived quantitatively in terms of their energies.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.1149-1152
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• 1999

In this paper we analyzed each region of specific points and ｅ-Δｅphase plane in order to make fuzzy rule base. After we composed the fuzzy control rules which can decrease rise time, delay time, maximum overshoot than basic fuzzy control rules. The composed method are converged more rapidly than single rule base in convergence region. Proposed method is alternately use at specific points of ｅ-Δｅphase plane with two fuzzy control rules, that is one control rule occruing the steady state error used in transient region and another fuzzy control rule use to decrease the steady state error and rapidly converge at the convergence region. Two fuzzy control rules in the ｅ-Δｅ phase plane decide the change time according to response characteristics of plants. As the results of simulation through the second order plant and the delay time plan, Proposed dual fuzzy control rules get the good response compare with the basic fuzzy control rule.