• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.58-60
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• 2020

본 논문에서는 2개의 인-휠 브러쉬리스 모터로 구동하는 차량의 실시간 위치 추종 제어방법을 제안한다. 2개의 모터를 사용하여 구동되는 차량의 경우 방향 및 이동이 각 모터의 제어를 기반으로 결정된다. 하지만 컨트롤러에 의해 지령된 위치까지 모터의 제어가 정확하게 된다 하더라도 차량의 실제 위치는 바퀴와 바닥면사이의 슬립이나 외부 요인에 의해 오차가 발생하게 된다. 따라서 이렇게 발생하는 오차를 보상하기 위해 차량의 실시간 각도 추정이 가능한 IMU(Inertia Measrement Unit) 센서를 기반으로 진행 각도를 보정하며 주행 중 발생하는 위치오차를 보상하기 위해 모터의 홀센서로부터 계산되는 위치와 IMU 센서의 데이터를 조합하여 실시간 위치 추종 제어방법을 제안한다.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.79-86
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• 2008

This paper proposed the appropriate installation angle of skewed sensors for measuring vehicle wandering data, which are collected to figure out the location of dynamic weight of a moving vehicle on roadways. We developed a device using tape-switch sensors and a computer program and collected vehicle wandering data with the device and probe vehicles. As a result, the steeper the skewed sensor was installed, the lower the error was shown. However, we could not collect proper data when a skewed sensor was set up higher than $30^{\circ}$ due to tandem axle. Therefore, this study suggested the appropriate angle of skewed sensors as a degree of $20^{\circ}$ to $25^{\circ}$ for gathering wandering data.

• The Journal of Korean Society for Radiation Therapy
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• v.32
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• pp.61-71
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• 2020

Purpose: To investigate the effect of collimator angle on plan quality of PAN-Pelvis Multi-isocenter VMAT plan, dose reproducibility at the junction and impact on set-up error at the junction. Material and method: 10 adult patients with whole pelvis cancer including PAN were selected for the study. Using Trubeam STx equipped with HD MLC, we changed the collimator angle to 20°, 30°, and 45° except 10° which was the default collimator angle in the Eclipse(version 13.7) and all other treatment conditions were set to be the same for each patient and four plans were established also. To evaluate these plans, PTV coverage, coverage index(CVI) and homogeneity index (HI) were compared and clinical indicators for each treatment sites in normal tissues were analyzed. To evaluate dose reproducibility at the junction, the absolute dose was measured using a Falmer type ionization chamber and dose changes at the junction were evaluated by moving the position of the isocenter in and out 1~3mm and setting up the virtual volume at the junction. Result: CVI mean value was PTV-45 0.985±0.004, PTV-55 0.998±0.003 at 45° and HI mean value was PTV-45 1.140±0.074, and PTV-55 1.031±0.074 at 45° which were closest to 1. V20Gy of the kidneys decreased by 9.66% and average dose of bladder and V30 decreased by 1.88% and 2.16% at 45° compared to 10° for the critical organs. The dose value at the junction of the plan and the actual measured were within 0.3% and within tolerance. At the junction, due to set-up error the maximum dose increased to 14.56%, 9.88%, 8.03%, and 7.05%, at 10°, 20°, 30°, 45°, and the minimum dose decreased to 13.18%, 10.91%, 8.42%, and 4.53%, at 10°, 20°, 30°, 45° Conclusion: In terms of CVI, HI of PTV and critical organ protection, overall improved values were shown as the collimator angle increased. The impact on set-up error at the junction by collimator angle decreased as the angle increased and it will help improve the anxiety about the set up error. In conclusion, the collimator angle should be recognized as a factor that can affect the quality of the multi-isocenter VMAT plan and the dose at the junction, and be careful in setting the collimator angle in the treatment plan.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.108-109
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• 2019

현대 산업기기의 큰 비중을 차지하는 전동기는 벡터 제어를 위해 각도 정보를 필수적으로 요구한다. 따라서, 엔코더와 권선형 레졸버 그리고 릴럭턴스 레졸버와 같은 많은 각도 센서가 활발히 사용되고 있다. 센서리스와 같이 센서를 이용하지 않고 각도를 추정하는 연구도 많이 진행되고 있지만, 높은 안정성을 요구하는 시스템에서는 여전히 각도 센서가 주를 이루고 있다. 각도 센서 중에서 높은 정확도와 안정성 그리고 내구성을 가지는 레졸버가 각광받고 있으며, 특히 릴럭턴스 레졸버(Variable Reluctance Resolver)가 많이 사용된다. 본 논문은 전동기의 제어 성능과 안정성을 높이기 위한 고성능 레졸버 설계의 내용을 담고 있으며, 기존의 릴럭턴스 레졸버와 달리 레졸버 고정자의 치폭을 변조하여 각도 오차를 줄이는 내용을 다루고 있다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.8
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• pp.16-21
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• 2012

The gyro sensor that made by MEMS process is generated an accumulated error(drift) and escape the zero angle following during calculation of rotate angle. This study propose BACF(Boot Angle Compensation Filter) algorithm for prevent escape zero angle and DCF algorithm for remove accumulated error. DCF algorithm is designed for acquire accurate turn of ratio by remove offset and noise components. BACF algorithm is obtained average offset that removed noise components by recursively calculate. Experimental environment, two-axis gyro sensor and mobile OIS camera mounted control board and 5Hz oscillation of ${\pm}0.5^{\circ}$ for the experiments were carried out. BACF and DCF algorithm is applied and the resulting accumulated error did not occur and exactly zero angle following results were made.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.636-642
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• 1996

본 연구는 4축 또는 5축 NC 공작기계에 사용되는 Rotary Table의 오차를 측정하고 이를 보정하기 위한 연구이다. 먼저 일반적인 Rotary Table에 대한 오차모델이 설정되었으며, Rotary Table에서 존재하는 6가지의 오차를 각각 측정하였다. 측정방법은 3개의 길이오차는 1 개의 정밀볼(Master ball)과 3개의 LVDT, 3개의 각도 오차는 6각 폴리곤과 Autocollimator를 사용하여 측정하였다. 측정된 오차 성분들은 오차모델을 이용하여 보상치를 계산하였으며, 이 값은 추후 원래의 측정오차와 비교하는 방법으로 모델의 정확성을 검증할 것이다. NC 공작기계상에서 Rotary Table의 실제 보상 실험을 위하여 30$^{\circ}$간격으로 정밀한 볼이 장착된 볼-테이블을 설계하였다.

• Journal of Convergence for Information Technology
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• v.10 no.6
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• pp.14-18
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• 2020

In this paper, when two sets of cross-eye jammer antennas are installed vertically to jam a monopulse radar, the jamming effects according to the jammer's phase difference, amplitude ratio, and radar angle of engagement are analyzed. The phase difference and amplitude ratio of the cross-eye jammer can be adjusted in the jammer, but since the angle of engagement is relatively determined by the radar, it is very important to respond to changes in the angle of engagement. The orthogonally deployed jammer antennas can be considered as a good way to increase the jamming effect while minimizing the hardware configuration, and the jamming effect is analyzed while changing the angle of inclination from 0° to 360°. This jammer greatly improves the jamming effects at the angles of incidence 45°~135° and 225°~315°, compared to a single jammer. And it is expected to be useful in the design of cross-eye jammers for military aircraft and ships.

• Journal of Platform Technology
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• v.12 no.1
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• pp.44-54
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• 2024

The existing indoor positioning methods using beacons or tags suffer from issues such as occasional undetection or increased errors due to noise. In this paper, we propose a method for determining the indoor position of a robot using the distance and, the angle between the direction of a target object whose position is known and the direction in which the robot views the target object from the front. The method proposed in this paper utilizes a depth camera to measure distance and calculate angles. Distance is measured using depth information captured by the camera, while angles are determined using images captured by the camera to determine the orientation of the target object. The proposed method calculates coordinate displacements using distance and angle. And then the method determines the position of the mobile robot using these displacements and the coordinates of the target object. To show the applicability of the proposed method for indoor positioning, we conducted experimental implementation and compared measured displacements. The results showed errors within 50mm, but considering the size of the mobile robot, it is judged that the method proposed in this paper can be sufficiently used for indoor positioning.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.23-29
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• 2015

In this paper, we introduce a underwater ranging algorithm with Look-up Table (LUT) by modifying the existing method which is using the changes of angles of accoustic rays with SSP (Sound Speed Profile). We compare the horizontal distance errors and the calculation times. Our new algorithm exploits Time of Arriva l(ToA) - horizontal distance table based on SSP. This algorithm offers faster calculation speed than the previous one with the slight increase of the distance estimation error.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.2
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• pp.199-205
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• 2004

There are many antenna array errors. They will distort the array beam pattern and result in an increased sidelobe level. A calibration technique is proposed for correcting the antenna array errors such as mutual coupling and unequal feeder characteristics. These are modeled as a matrix representing the interaction between the radiating elements. The matrix is estimated from the measured array response vectors. The antenna array errors are corrected by modifying the beamforming weight vector. It is verified by the electromagnetic simulation and experiment that the proposed technique reduces the sidelobe level and increases the antenna gain.