• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.279-285
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• 1993

This paper presents a precision automatic measuring system for ball screw Pitch. Ball screw is mounted on a precision indexing table, and the ball screw pitch is measured via magnetic scale, where the indexing and measurement are performed by a PC. For precision indexing of ball screw, direct driven motor is coupled to the designed dead and live centers; the performance of the centers are assessed with a precision master sylinder,such as radial motion,tilt motion, and axial motions. An error compensation model is constructed for the measurement system of ball screw pitch, where the error motions of indexing system as well as the scale measurement system are combined to give the measurement error for the ball screw. The developed system proposes an automated precision measurement system for manufacturers and users of ball screw.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.619-623
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• 1996

This paper proposes the thermal characteristics of motor integrated spindle on high precision lathe and investigates the thermal deformation and the running error of spindle. The deformation and the running error of spindle shaft are continuously measured by the gapsensor mounted on machine. The temperature distribution is measured bythe thermal vision system and the thermocouple. The results show that the running error of spindle is dependent on the rotational speed and the thermal deformation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.1037-1038
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.851-852
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• 2009

• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.607-614
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• 2013

In this study, effect of the sensor gain error is theoretically analyzed and simulated when mixed sequential two-prove method(MTPM) is applied for the precision measurement of straightness error of a linear motion table. According to the theoretical analysis, difference of the gain errors between two displacement sensors increases measurement error dramatically and alignment error of the straightedge is also amplified by the sensor gain difference. On the other hand, if the gain errors of the two sensors are identical, most of error terms are cancelled out and the alignment error doesn't give any influence on the measurement error. Also the measurement error of the straightness error is minimized compared with that of the straightedge's form error owing to close relationship between straightness error and angular motion error of the table in the error terms.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.4
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• pp.44-48
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• 2006

Recently, demand the ultra precision product which is increasing rapidly is used extensively frontier industry field such as semi-conductor, computer, aerospace, precision machine. Ultra precision processing is the portion that is very needed to NT in the field of mechanical engineering. The latest date, together with radical advancement of electronic and photonics industry, necessity of ultra precision processing is on the increase for the manufacture of various kernel parts those are connected with these industrial fields. Specially, require motion accuracy of high resolution of nm order in stroke of hundreds millimeters according as diameter of processing object great and processing accuracy rises. In this case ,the response speed absolute delay because inertial mass of moving part is very large. Therefore, real time motion error compensation becomes very hardly. In this paper, we used ultra precision cutting unit(UPCU) to cope such problem. a UPCU is designed and tested to obtain sub-micrometer from accuracy in diamond turning of flat surfaces. The thermal growth spindle error is compensated for real time using a UPCU driven by piezoelectric actuator along with a laser encoder displacement sensor.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.64-71
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• 2004

The growing need for higher precision and productivity in manufacturing industry has lead to an increased interest in computer numerical control (CNC) systems. It is well known fact that the cross-coupling controller (CCC) is an effective method for contouring applications. In this paper, a multi-axis contour error controller (CEC) based on a contour error vector using parametric curve interpolator is introduced. The contour error vector is a vector from the actual tool position to the nearest point on the desired path. The contour error vector is the closest error model to the contour error. The simulation results show that the CEC is more accurate than the conventional CCC for a biaxial motion system. In addition, the experimental results on 3-axis motion system show that the CEC is simply applied to 3-axis motions and contouring accuracy is significantly improved.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.6 no.4
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• pp.71-75
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• 2007

Geometrical error of ultra-precision machining due to spherical tool alignment error is analyzed. Deviation of spherical edge, ranged several ten micrometers, generates vertical and horizontal error of tool path and affects profile accuracy of machined surface. Simulation of machined error shows effect of tool alignment error and enables to estimate alignment error. This work provides technical insights into the minimizing of geometrical error of ultra-precision machining.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.10
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• pp.1483-1488
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• 2012

This paper analyzed the precision and accuracy of the altitude-aided GNSS using the altitude information from digital map. The precision of altitude-aided GNSS is analysed using the theoretically derived DOP. It is confirmed that the precision of altitude-aided GNSS is superior to the general 3D positioning method. It is also shown that the DOP of altitude-aided GNSS is independent of altitude bias error while the accuracy was influenced by the altitude bias error. Furthermore, it is shown that, since the altitude bias error influenced differently to each pseudorange measurement, the effect of the altitude bias error is more serious than clock bias error which does not influence position error at all. The results are evaluated by the simulation using the commercial RF simulator and GPS receiver. It confirmed that altitude-aided GNSS could improve not only precision but also accuracy if the altitude bias error are small. These results are expected to be easily applied for the performance improvement to the land and maritime applications.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.6
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• pp.117-126
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• 1994

This paper describes an application step of a $R^{-{\theta}}$ method which measures circular movements in machining centers. The detection of composite errors of circular movements and a high precision cutting method in machining centers were investigated by the analysis of data measured by $R^{\theta }$method which can detect the rotating angle and is applicable to variable measuring radius. When the error by squareness error and unbalance of position-loop-gain were mixed, the detection method of each error was proposed. Although the errors by squarenss error and backlash compensation were mixed, the errors by squareness error be detected. If the errors by unbalance of position-loop-gain and backlash compensation were mixed, the errors by unbalance of position-loop-gain could not detected. A high precision cutting mehod, which uses the NC program compensated by using feed-back data from error measured by the $R^{\theta }$method, was proposed.