• Journal of international Conference on Electrical Machines and Systems
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• 제2권2호
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• pp.184-189
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• 2013

This paper proposes a method for improving the performance of a position sensorless control system for a slotless surface permanent magnet synchronous motor (SPMSM) in a very low-speed region. In position sensorless control based on a motor model, accurate motor parameters are required because parameter errors would affect position estimation accuracy. Therefore, online parameter identification is applied in the proposed system. The error between the reference voltage and the voltage applied to the motor is also affect position estimation accuracy and stability, thus it is compensated to ensure accuracy and stability of the sensorless control system. In this study, two voltage error compensation methods are used, and the effects of the compensation methods are discussed. The performance of the proposed sensorless control method is evaluated by experimental results.

• 항공우주시스템공학회지
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• 제15권3호
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• pp.57-64
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• 2021

본 연구에서는 KV의 유도조종오차를 최소화하여 직격요격 성능을 확보하고자 DACS 구동장치에 대한 위치정확도 점검방안을 제안하였다. DACS 구동장치의 정확도 성능은 탄도미사일 요격에 중요한 성능 중 하나이다. DACS 구동장치의 정확도 성능을 검증하기 위해 위치정확도란 점검 항목을 도출하였고, 이에 대한 점검시스템 설계 및 점검절차를 기술하였다. 핀틀 위치정확도 점검시스템은 레이저 변위센서를 이용하여 핀틀의 구동변위를 외부 계측할 수 있도록 구성하였고, 외부 계측한 데이터는 실시간으로 구동명령 및 피드백 데이터와 비교분석할 수 있도록 설계하였다. 본 논문에서 제안하는 위치정확도 점검시스템은 DACS 조립체 뿐만 아니라 유도탄 조립체 단위에서도 점검이 가능하도록 설계하였다. 설계된 점검시스템을 이용하여 핀틀의 위치정확도 점검을 수행하였고, 점검 결과를 분석하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권8호
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• pp.452-461
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• 2003

The reliability and accuracy of the information on control rod position are very important to the reactor safety and the design of the core protection system. A survey on the RSPT(Reed Switch Position Transmitter) type control rod position indicator system and its actual implementation in the existing nuclear power plants in Korea was performed first. The control rod position indicator having the high performance for SMART was developed on the basis of RSPT technology identified through the survey. The arrangement of permanent magnet and reed switches is the most important procedure in the design of control rod position indicator. The hysteresis of reed switches is one of the important factors in a repeat accuracy of control rod position indicator as well. This paper investigates efficiency of the magnetic flux concentrator and the hysteresis using FEM and verified differences in physicals characteristics by comparing the results of FEM and those of the experiment. As a result, it is shown that the characteristics of prototype control rod position indicator have a good agreement with the results of FEM.

• 제어로봇시스템학회논문지
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• 제7권5호
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• pp.399-406
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• 2001

This paper presents a dynamic modeling and a sliding mode controller for the high-speed/high-accuracy position control system. The selected target system is the wire bonder assembly which is used in the semiconductor assembly process. This system is a reciprocating one around the pivot point that consists of VCM(voice coil motor) as an actuator and transducer horn as a bonding tool. For the modeling elements, the sys-tem is divided into electrical circuit, magnetic circuit and mechanical system. Each system is modeled using the bond graph method and united into the full system. Two major aims are considered in the design of the controller. The first one is that the horn must track the given reference trajectory. The second one is that the controller must be realizable by using the DSP board. Computer simulation and experimental results show that the designed sliding mode controller provides better performance than the PID controller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.820-825
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• 1996

This paper is concerned with effective operating method of pneumatic on-off valves for improving position control accuracy, valve life-time and position settling time using modified pulse width modulation with dead-zone. The pneumatic system using on-off valves studied in this paper has advantage of simple construction and low cost compared with a system with servo-valves. The performance of proposed control system is investigated experimentally for the position control of a pneumatic cylinder using on-off valves. Experimental results show that the proposed algorithm for valve operation can be used to obtain fast and accurate position control and to prevent on-off valves from unnecessary switching.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.434-434
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• 2000

It is the main problem to measure the position and orientation of a robot end effector for the calibration of robots. The calibration methods can be used as a tool to improve the accuracy of robots without change of the arm or control architecture of robots. But such calibration methods require the accurate measurements. Dynamic measurement of position and orientation Provides a solution of this problem and improves dynamic accuracy by dynamic calibration o( robots. This paper describes the development o( the laser tracking system capable of determining the static and dynamic performance of industrial robots. The structure and system components are presented and basic experimental results are included to demonstrate the instrument performance. The system can be applied to the remote controlled mobile robots as weil as the calibration of robots.

• 한국산학기술학회논문지
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• 제14권1호
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• pp.94-100
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• 2013

본 연구에서는 VRS GNSS(GPS/GLONASS)를 이용하여 지적측량에서의 위치결정 정확도를 분석하여 보고, 이를 토대로 성과결정의 정확도 향상 가능성을 제시하고자 하였다. 연구결과 GPS 위성데이터만을 수신 한 결과 보다 GPS/GLONASS 위성데이터을 통합으로 수신해 위치를 결정한 결과가 대략 3cm 정도 위치정확도가 높은 것으로 분석되었다. 따라서 VRS GNSS 통합 수신 방식이 지적측량에 도입된다면 위치 정확도 향상을 기대할 수 있을 것으로 보인다.

• 제어로봇시스템학회논문지
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• 제6권11호
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• pp.987-994
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• 2000

A Linear Pulse Motor (LPM) is a direct drive motor that has good performance in terms of accuracy, velocity and acceleration compared to the conventional rotating system with toothed belts and ball screws. However, since an LPM needs supporting devices which maintain constant air-gap and has strong nonlinearity caused by leakage magnetic flux, friction and cogging, etc., there are many difficulties in improvement on accuracy with conventional control theory. Moreover, when designing the position controller of LPM, the modeling error and load variations has not been considered. In order to compensate these components, the neural network with conventional feedback controller is introduced. This neural network of feedback error learning type changes the current commands to improve position accuracy. As a result of experiments, we observes that more accurate position control is possible compared to conventional controller.

• Spatial Information Research
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• 제9권2호
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• pp.263-275
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• 2001

NGIS 사업으로 구축된 1/1,000 수치지도의 활용이 급증하면서 이를 활용하기에 앞서 수치지도의 위치정확도 검증이라는 문제가 대두되고 있다. 본 연구에서는 학교 시설물관리시스템 구축에 기반이 되는 소규모 지역에 대한 1/1,000 수치지도의 위치 정확도를 평가하고, 위치오차가 발생한 지역에 대한 수치지도 수정/갱신 방안을 제시하였다. RTK방법으로 교내 주요건물에 대한 위치오차를 평가해 볼 때, 측량관계법령에서 규정하고 있는 0.5mm 보다 크게 나타났다. 이에 대한 위치정확도 확보방안으로 먼저, 교내에 Static 측량을 실시하여 측량기준점을 선정한 후 기준점으로부터 주요건물에 대한 좌표값을 평가하여 RTK 방법으로 측량한 좌표값과 비교하였다. 두 번째로는 지도를 변환하였으며 그 결과를 RTK 측량성과와 비교하였다. 첫 번째 방법과 두 번째 방법을 검토하여 소규모 적합한 수치지도 위치정확도 확보방안을 제시하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.521-527
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• 2002

This paper presents a dynamic modeling and a robust PID controller design process for the wire bonder head assembly. For the modeling elements, the system is divided into electrical system, magnetic system, and mechanical system. Each system is modeled by using the bond graph method. The PID controller is used for high speed/high accuracy position control of the wire bonder assembly. The Taguchi method is used to evaluate the more robust PID gain combinations than conventional one. This study makes use of an L18 array with three parameters varied on three levels. Computer simulations and experimental results show that the designed PID controller provides more improved signal to noise ratio and reduced sensitivity than the conventional PID controller.