• 대한임베디드공학회논문지
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• 제9권1호
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• pp.43-52
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• 2014

This paper presents a tracking system using images captured from a camera on a moving platform. A camera on an unmanned flying vehicle generally moves and shakes due to external factors such as wind and the ego-motion of the machine itself. This makes it difficult to track a target properly, and sometimes the target cannot be kept in view of the camera. To deal with this problem, we propose a new system for stable tracking of a target under such conditions. The tracking system includes target tracking and 3-axis camera motion compensation. At the same time, we consider the simulation of the motion of flying vehicles for efficient and safe testing. With 3-axis motion compensation, our experimental results show that robustness and stability are improved.

• 한국정밀공학회지
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• 제34권1호
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• pp.53-58
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• 2017

A fine stage is developed for the 3-DOF error compensation of a linear axis in order to improve the positioning accuracy. This stage is designed as a planar parallel mechanism, and the joints are based on a flexure hinge to achieve ultra-precise positioning. Also, the effect of Abbe's offsets between the measuring and driving coordinate systems is minimized to ensure an exact error compensation. The mode shapes of the designed stage are analyzed to verify the desired 3-DOF motions, and the workspace and displacement of a piezoelectric actuator (PZT) for compensation are analyzed using forward and inverse kinematics. The 3-DOF error of a linear axis is measured and compensated by using the developed fine stage. A marked improvement is observed compared to the results obtained without error compensation. The peak-to-valley (PV) values of the positional and rotational errors are reduced by 92.6% and 91.3%, respectively.

• 한국기계가공학회지
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• 제6권3호
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• pp.53-57
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• 2007

This paper presents a geometrical error compensation of tool alignment for B axis controlled machine. In precision machining, tool alignment is crucial parameter for machined surface. To decrease tool alignment error, plus tilted tool from B axis center is touched to reference work piece and checked the deviation from original position. Same process is performed in minus tilt. Comparing these 2 touch positions, wheel alignment error in X axis and Z axis can be calculated on B axis center. Experimental results show that this compensation method is efficient to correct tool alignment.

• 한국정밀공학회지
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• 제16권8호
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• pp.122-129
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• 1999

A 5-axis CNC machine tool is more useful compared with a 3-axis machine tool, because the position and the orientation of a tool tip can be controlled simultaneously. Unlike the 3-axis machine tool, the 5-axis machine tool has the volumetric position error and volumetric orientation error due to the quasi-static error of each machine tool joint which is a major source of machined part error. So, the generalized error synthesis model of the 5-axis CNC machine tool was developed to predict and to compensate for the volumetric position error and the volumetric orientation error. It was proposed that a compensation algorithm to correct simultaneously the volumetric position error and the volumetric orientation error of the 5-axis CNC machine by error inverse kinematic.

• 한국정밀공학회지
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• 제14권11호
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• pp.84-92
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• 1997

The purpose of this study is to develop a geometric error model and path compensation algorithm for rotating axes of the 5-axis machine tools, by a method to calibrate a rotary table using one master ball and three LVDTs. It was developed a new methodology to measure 3 translation errors of the rotary table and with a compensation procedure for setup errors of the master ball. The method is experimentally verified using a ball-table and on-machine inspection method. The results showed that the geometric error models with the path compensation strategy can be practically used as a means for improving the accuracy of the machine tools with rotary table.

• 한국정밀공학회지
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• 제32권7호
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• pp.643-651
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• 2015

Multi-axis magnetic and accelerometer sensor are widely used in consumer product such as smart phones. The vector output of multi-axis sensors have errors on each axis such as offset error, scale error, non-orthogonality. These errors cause many problems on the performance of the applications. In this paper, we designed the effective inline compensation algorithm for calibrating of 3 axis sensors using ellipsoid for mass production of multi-axis sensors. The outputs with those kinds of errors can be modeled by ellipsoid, and the proposed algorithm makes sequential mappings of the virtual ellipsoid to perfect sphere which is calibrated function of the sensor on three-dimensional space. The proposed calibrating process composed of four main stages and is very straightforward and effective. In addition, another imperfection of the sensor such as the drift from temperature can be easily inserted in each mapping stage. Numerical simulation and experimental results shows great performance of the proposed compensation algorithm.

• 센서학회지
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• 제21권3호
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• pp.198-203
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• 2012

In this paper, the driving information system of the bicycle has been studied by using the 3-axis acceleration sensor. The sensor module composed of 3-axis acceleration sensor and MCU(Microcontroller Unit) was mounted onto the handle of bicycle and the experiments were conducted on the flatland, uphill and downhill of bicycle road. Three axis acceleration values were converted to the pitch and roll angles, then four major compensation methods have been applied to achieve meaningful data for driving information system. The experimental results of pitch angles showed 2.46, -1.26, 7.79 degrees in case of flatland, uphill, downhill, respectively. When the steering handle turned to the left direction, roll angles showed -29.35, -41.67, -36.98 degrees at each road condition. With the right-turn, roll angles presented 20.05, 33.75, 24.44 degrees in case of flatland, uphill, and downhill, respectively. The pitch angle has been increased more than 40 degrees at stop mode. By using the change of pitch and roll angles, we could obtain the driving information system of bicycle successfully.

• 한국기계가공학회지
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• 제8권3호
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• pp.1-6
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• 2009

This paper presents a geometrical error compensation of tool alignment for sharp edge bite on B axis controlled machine. In precision micro patterning, bite alignment is crucial parameter for machined surface. To decrease bite alignment error, plus tilted bite from B axis center is touched to reference work piece(pin gauge) and checked the deviation from original position. Same process is repeated for maximum touch deviation value. From this touched position value, wheel alignment error in X axis and Z axis can be calculated on B axis center. Experimental results show that this compensation method is efficient to correct sharp edge bite alignment.

• 정보저장시스템학회논문집
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• 제3권4호
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• pp.191-195
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• 2007

The optical disc drive has used a high NA objective lens and a shorter wavelength laser diode for high recording density. But high NA and shorter wavelength cause several margins to become short. Focusing and tracking servo has to be more accurate and active tilt compensation mechanism is also needed for coma aberration compensation. In this paper, we proposed 3-axis moving magnet type actuator. For 3-DOF motion, moving coil actuator has to be equipped with 6 wires for supplying 3 independent signals. However, moving magnet type actuator doesn't need to change the configuration of wires because coils are in stator. So, we added a tilt mechanism to the 2-axis moving magnet actuator which is designed in previous research. Addition of the tilt mechanism cuts down the focus sensitivity. So, maximization the tilting sensitivity and securing the focusing sensitivity are objectivities of this research. DOE (design of experiments) procedures of electromagnetic circuit are performed for parameter study and the optimization is also performed to maximize the tilt sensitivity. And then the final design is suggested and its performance is verified by FE simulation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1033-1036
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• 2007

The optical disc drive has used a high NA objective lens and a shorter wavelength laser diode for high recording density. But high NA and shorter wavelength cause several margins to become short. Focusing and tracking servo has to be more accurate and active tilt compensation mechanism is also needed for coma aberration compensation. In this paper, we proposed 3-axis moving magnet type actuator. For 3-DOF motion, moving coil actuator has to equip 6 wires for supplying 3 independent signals. However, moving magnet type actuator doesn't need to change the configuration of wires because coils are in stator. So, we added tilting mechanism to 2-axis moving magnet actuator which is designed in previous research. Addition of the tilting mechanism cuts down the focusing sensitivity. So, maximization the tilting sensitivity and securing the focusing sensitivity are objectivities of this research. DOE (design of experiments) procedures of electromagnetic circuit are performed for parameter study and the optimization is also performed to maximize the tilt sensitivity. And then the final design is suggested and its performance is verified by FE simulation.