• Journal of the Korean Society for Precision Engineering
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• v.28 no.8
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• pp.904-914
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• 2011

The volumetric errors of CNC machining centers are determined by 21 errors, including 3 linear errors, 6 straightness errors, 3 perpendicular errors, 9 angular errors and non-rigid body errors of the machine tool. It is very time consuming and hard to measure all of these errors in which laser interferometer and other parts are used directly. Hence, as many as 21 separate setups and measurements are needed for the linear, straightness, angular and perpendicular errors. In case of the 5-axis machining centers, two more rotary tables are used. It can make 35 error sources of the movement. Therefore, the measured errors of multi movements of the 5-axis tables are very complicated, even if the relative measured errors are measured. This paper describes the methods, those analyze the error sources of the machining centers. Those are based on shifted diagonal measurements method (SDM), R-test and Double ball bar. In case, the angular errors of machine are small enough comparing with others, twelve errors including three linear position errors, six straightness errors and three perpendicular errors can be calculated by using SDM. To confirm the proposed method, SDM was applied to measuring 3 axes of machine tools and compared with directly measurement of each errors. In addition, the methods for measuring relative errors of multi-axis analysis methods using R-test and Double Ball Bar are introduced in this paper.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.347-354
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• 2021

In the equipment industry such as chemical plants, high temperature, high pressure, and toxic fluids move between various facilities through piping. The movement and damage of pipes due to changes in the surrounding environment such as temperature changes, vibrations, earthquakes, and ground subsidence often lead to major accidents involving personal injury. In order to prevent such an accident, various types of expansion joints are used to absorb and supplement various shocks applied to the pipe to prevent accidents in advance. Therefore, it is very important to measure the deformation of the used expansion joint and predict its lifespan to prevent a major accident. In this paper, the deformation of the expansion joint was understood as a kind of motion, and the change was measured using a Hall Effect Sensor and a 9-Axis Sensor. In addition, we studied a system that can predict the deformation of expansion joints by collecting and analyzing the measured data using a general-purpose microcomputer (Arduino Board) and C language.

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.3
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• pp.43-53
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• 1991

It is important to harmonize the occlusion with TMJ and neuromuscular system. However, clinically, how to harmonize is very difficult. The mandibular movement is the motion in which all component part of stomatognathic system participate. This study was performed to compare mandibular movement of mandibular prognathic patients group with that of normal group, to ascertain which components of mandibular movement have differences between two groups, and to use for occlusal treatment of mandibular movement. Thirteen adult who have physiologically normal occlusion and are free of TMJ dysfunction were selected as a control group(Group 1). Eight adult who are mandibular prognathic patient and have more than four anterior teeth crossbite, therefore have not anterior guidance function and have posterior interference at protrusion were selected as a experimental group(Group 2). Electronic pantograph, Denar Pantronic (Denar Corp., U.SA.), was used to record mandibular movement. Pantronic survey was performed by using an arbitrary hinge axis according to manufacturer's direction. Of the Pantronic recordings, immediate side shift (ISS), progressive side shift (PSS), orbiting condylar path (ORB), protrusive condylar path (PRO) between two groups were compared and analysed. The results were as follows: 1. The average protrusive and orbiting condylar inclination of mandibular prognathic patient$(28.44^{\circ},\;36.94^{\circ})$ was significantly lower than those of normal group$(40.15^{\circ},\;48.00^{\circ})$ (P<0.01). 2. There was no statistically significant difference between .the average immediate and progressive side shift of mandibular prognathic patient $(0.37mm,\;6.19^{\circ})$ and those of normal group$(0.52mm.\;5.96^{\circ})$ (P>0.01). 3. The significant correlation was found between orbiting condylar inclination and protrusive condylar inclination.

• Journal of radiological science and technology
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• v.33 no.4
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• pp.379-386
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• 2010

This study evaluated the motion of tumors during the entire period of therapy and the accuracy of radiosurgery among forty eight lung tumor patients who were underwent radiosurgery using the CyberKnife Synchrony Respiratory Tracking System. The motion of lung tumor was measured by the coordinates of a gold acupuncture needle inserted into the tumor or the area around the tumor using the CyberKnife image guided system. Then the accuracy of radiosurgery was evaluated based on the error of correlation computed with the motion tracking system. The lung tumor motion is Cranio-Caudal direction by an average of $2.63{\pm}1.87\;mm$, moved left-right direction by $1.13{\pm}0.71\;mm$, and anterior-posterior direction by $1.74{\pm}1.16\;mm$. The degree of rotational movement was $1.66{\pm}1.66^{\circ}$ on X axis, $1.20{\pm}0.97^{\circ}$ on Y axis, and $1.18{\pm}0.73^{\circ}$ on Z axis. The vector of translation movement was measured to be $3.78{\pm}2.00\;mm$ on the average. The results show that directions of Cranio-Caudal(p < 0.001), anterior-posterior direction(p < 0.029), and three dimensional vector value(p < 0.002) showed statistical significance, because the lower side of tumor showed more intensive movement compared to the upper side of tumor. The radiosurgery was carried out by compensating the motion of tumor after accurate investigation of the correlation error with the average of $0.95{\pm}0.62\;mm$ during the lung tumor radiosurgery with the CyberKnife Synchrony Respiratory Tracking System.

• Radiation Oncology Journal
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• v.26 no.4
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• pp.263-270
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• 2008

Purpose: This study aimed to quantitatively measure the movement of tumors in real-time and evaluate the treatment accuracy, during the treatment of a liver tumor patient, who underwent radiosurgery with a Synchrony Respiratory motion tracking system of a robot CyberKnife. Materials and Methods: The study subjects included 24 liver tumor patients who underwent CyberKnife treatment, which included 64 times of treatment with the Synchrony Respiratory motion tracking system ($Synchrony^{TM}$). The treatment involved inserting 4 to 6 acupuncture needles into the vicinity of the liver tumor in all the patients using ultrasonography as a guide. A treatment plan was set up using the CT images for treatment planning uses. The position of the acupuncture needle was identified for every treatment time by Digitally Reconstructed Radiography (DRR) prepared at the time of treatment planning and X-ray images photographed in real-time. Subsequent results were stored through a Motion Tracking System (MTS) using the Mtsmain.log treatment file. In this way, movement of the tumor was measured. Besides, the accuracy of radiosurgery using CyberKnife was evaluated by the correlation errors between the real-time positions of the acupuncture needles and the predicted coordinates. Results: The maximum and the average translational movement of the liver tumor were measured 23.5 mm and $13.9{\pm}5.5\;mm$, respectively from the superior to the inferior direction, 3.9 mm and $1.9{\pm}0.9mm$, respectively from left to right, and 8.3 mm and $4.9{\pm}1.9\;mm$, respectively from the anterior to the posterior direction. The maximum and the average rotational movement of the liver tumor were measured to be $3.3^{\circ}$ and $2.6{\pm}1.3^{\circ}$, respectively for X (Left-Right) axis rotation, $4.8^{\circ}$ and $2.3{\pm}1.0^{\circ}$, respectively for Y (Crania-Caudal) axis rotation, $3.9^{\circ}$ and $2.8{\pm}1.1^{\circ}$, respectively for Z (Anterior-Posterior) axis rotation. In addition, the average correlation error, which represents the treatment's accuracy was $1.1{\pm}0.7\;mm$. Conclusion: In this study real-time movement of a liver tumor during the radiosurgery could be verified quantitatively and the accuracy of the radiosurgery with the Synchrony Respiratory motion tracking system of robot could be evaluated. On this basis, the decision of treatment volume in radiosurgery or conventional radiotherapy and useful information on the movement of liver tumor are supposed to be provided.

• Journal of the Korean Solar Energy Society
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• v.21 no.4
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• pp.55-62
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• 2001

A parabolic dish concentrator used in a high temperature application of solar energy tracks the sun's movement by two axis sun tracking system. In such a system, sun tracking performance affects the system efficiency directly. Generally the higher the tracking accuracy is, the better the system performance is. A large number of parabolic dish type concentrators has been developed and implemented in the world. However none of them clearly provided a qualitative method of how the accuracy of the sun tracking system can be evaluated. The work presented here is the evaluation of sun tracking performance of parabolic dish concentrator, which follows the sun's movement by the sensor, using a computer vision system. We install a camera on the parabolic dish concentrator. While the concentrator follows the sun, sun's images are captured continuously. Then the performance of sun tracking system was evaluated by analyzing the variation of the position of the sun in the captured images.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.133-139
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• 2010

From the ancient times, there are waves in the ocean. And all the moving body have energy. We have a kind of hope to convert the wave energy into electric one. Finally we can find out a power generator mechanism that mainly use the principle of pulleys. We have made drawings for this and completed the wave energy converter. This wave energy converter consists of several pulleys, rope, generator, buoys and anchors. The distance between an anchor and buoy is changed according to the hight of waves. Several sets of anchors, pulleys and buoys can make the movement of rope, and the ropes wind up a converter axis. In case of 1 meter movement of the buoy, the winding distance will be amplified 2 or 3 times if we use several moving and fixed pulleys. Based on this concept, we developed 2 kind of prototypes. One is for the test in the laboratory and the other is for the field test. Through the two test, we could confirm the usability of this mechanism.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.16-20
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• 1988

This paper presents a new algorithm for solving the inverse kinematics in real-time applications. The end-tip movement of each link can be resolved into the basic resolution unit, .DELTA.l, which depends on link length, reduction ratio and resolution of the incremental encoder attached to the joint. When x- and y-axis projection of the end-tip movement are expressed in .DELTA.l unit, projectional increments .DELTA.x and .DELTA.y become -1, 0 or I by truncation. By using the incremental computation with these ternary value and some simple logic rules, a coordinate transformation can be realized. Through this approach, it should be noted that the floating-point arithmetic and the manipulation of trigonometric functions are completely eliminated. This paper demonstrates the proposed method in a parallelogram linkage type, two-link arm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.647-652
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• 2000

This paper presents a study on the position tracking control of robot system on the uncertain elastic base. The elastic base is modeled as a virtual robot which has passive joints and the control strategy is using approximate Jacobian operators. Jacobian operators represent the overall robot system including base movement. However, because we don't know the base movement we can't estimate the jacobian operators directly. The control algorithm is proposed which uses only Jacobian operators of a real robot as approximate Jacobian operators. The measured errors from external sensor are compensated by approximate Jacobian operators. The simulation results of a single-axis robot system show that the control strategy can be used for position tracking.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.408-408
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• 2000

A parabolic dish concentrator used in a high temperature application of solar energy tracks the sun's movement by two axis sun tracking system. In such a system, sun tracking performance affects the system efficiency directly. Generally the higher the tracking accuracy is, the better the system performance is. A large number of parabolic dish type concentrators has been developed and implemented in the world. However none of them clearly provided a qualitative method of how the accuracy of the sun tracking system can be evaluated. The work presented here is the evaluation of sun tracking performance of parabolic dish concentrator, which follows the sun's movement by the sensor, using computer vision system. We install a camera on the parabolic dish concentrator. While the concentrator follows the sun, sun's images are captured continuously. Then the performance of sun tracking system was evaluated by analyzing the variation of the position of the sun in the images.