• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1429-1432
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• 2005

This work is towards the development of a low-cost, small-sized inertial navigation system(INS) which consists of 3 accelerometers, 3 semiconductor gyros and a magnetic compass sensor. This paper explains in detail the structure of the developed system and proposes a 3 dimensional attitude estimation algorithm with Indirect Kalman Filter. The experiments are performed with the developed system attached to a 6 DOF robot for showing the effectiveness of the algorithm.

• 로봇학회논문지
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• 제5권4호
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• pp.309-317
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• 2010

This paper proposes an efficient measurement system for the velocity and direction of the wind using the dual rotor wind power generator in vessel. Conventional digital measurement system recognizes the direction and the velocity of the wind using the electric compass or synchronous motor and Vane probe method using hall sensors. But each system has its own short-comings: the synchronous motor has a larger measurement error than the magnetic compass and magnetic compass is weak for the external disturbances such as fluctuation of the vessel. To compensate these short-comings, this paper proposes a new compensation algorithm for the fluctuation errors according to the external interference and the unexpected movement of the vessel along the roll and pitch directions. The proposed system is implemented with the dual compasses and a synchronous motor. The proposed independent power generation system can be operated by itself and can raise the efficiency of the wind power generation systems of 30 ~ 400 W installed along the vertical and horizontal axes. The proposed system also realizes the efficient and reliable power production system by the MPPT algorithm for the real-time recognition of the wind direction and velocity. An advanced switching algorithm for the battery charging system has been also proposed. Effectiveness of the proposed algorithm has been verified through the real experiments and the results are demonstrated.

• 제어로봇시스템학회논문지
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• 제19권5호
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• pp.481-487
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• 2013

This paper presents an FIR (Finite Impulse Response) fixed-interval smoothing filter for fast and exact estimating state variables of a discrete nonlinear system with modeling uncertainty. Conventional IIR (Infinite Impulse Response) filter and smoothing filter can estimate state variables of a system with an exact model when the system is observable. When there is an uncertainty in the system model, however, conventional IIR filter and smoothing filter may cause large errors because the filters cannot estimate the state variables corresponding to the uncertain model exactly. To solve this problem, FIR filters that have fast estimation properties and have robustness to the modeling uncertainty have been developed. However, there is time-delay estimation phenomenon in the FIR filter. The FIR smoothing filter proposed in this paper makes up for the drawbacks of the IIR filter, IIR smoothing filter, and FIR filter. Therefore, the FIR smoothing filter has good estimation performance irrespective of modeling uncertainty. The proposed FIR smoothing filter is applied to the integrated navigation system composed of a magnetic compass based DR (Dead Reckoning) and a GPS (Global Positioning System) receiver. Even when the magnetic compass error that changes largely as the surrounding magnetic field is modeled as a random constant, it is shown that the FIR smoothing filter can estimate the varying magnetic compass error fast and exactly with simulation results.

• ETRI Journal
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• 제34권3호
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• pp.379-387
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• 2012

In this paper, an error compensation technique for a dead reckoning (DR) system using a magnetic compass module is proposed. The magnetic compass-based azimuth may include a bias that varies with location due to the surrounding magnetic sources. In this paper, the DR system is integrated with a Global Positioning System (GPS) receiver using a finite impulse response (FIR) filter to reduce errors. This filter can estimate the varying bias more effectively than the conventional Kalman filter, which has an infinite impulse response structure. Moreover, the conventional receding horizon Kalman FIR (RHKF) filter is modified for application in nonlinear systems and to compensate the drawbacks of the RHKF filter. The modified RHKF filter is a novel RHKF filter scheme for nonlinear dynamics. The inverse covariance form of the linearized Kalman filter is combined with a receding horizon FIR strategy. This filter is then combined with an extended Kalman filter to enhance the convergence characteristics of the FIR filter. Also, the receding interval is extended to reduce the computational burden. The performance of the proposed DR/GPS integrated system using the modified RHKF filter is evaluated through simulation.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.177-180
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• 2002

In this paper, we has been studied self controlled mobile robot system with CCD camera. This system consists of TMS320F240 digital signal processor, step motor, RF module and CCD camera. 2-axis compass and magnetic sensor, we used wireless RF module for movable command transmiting between robot and host PC. This robot go straight until 95 percent filled screen with white color both side from input image. And the robot recognizes obstacle about 95 percent filled something, so it could turn for avoid the obstacle and conclude new path plan. it could get turning angle from 2-axis compass and magnetic sensor.

• 수산해양기술연구
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• 제35권1호
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• pp.11-18
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• 1999

In order to secure accuracy and effectiveness of the electromagnetic compass as information sensor for ship's head up bearing with gyro compass, magnetic compass and electromagnetic compass on the sea and on the dock in land.The results obtained were as follows;1. Between the Northeast and the southsouthwest the deviation on ship's head up bearing on electromagnetic compass got easterly deviation with max. $53^{\cire}$on the East and between the Southwest and the Northnortheast westerly deviation with max. $34^{\cire}$ on the Northwest, of which values were not able to be corrected due to the angle excess of deviation adjustment.2. The varies of deviation seemed to have a tendency to increase easterly deviation on the Northeast and the East, easterly deviation after westerly deviation between the South and the Northwest, small one on the North and the Southeast.3. The varies of deviation of ship were larger than the one of around the dock, were extreme on the bow of forecastle deck and were stable on the ship's center line of compass deck at the dock in land.

• 한국항해항만학회지
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• 제28권10호
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• pp.851-859
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• 2004

본 연구에서는 고정된 나침 방위에서 측정한 단일 자차만을 이용하여 자차계수 B와 C를 추정할 수 있는 새로운 방법을 기술하였다. 먼저, 4척의 미해군 함정에서 실제 측정한 자차를 이용하여 자차계수 B와 C만을 적용하여 자차합성하는 경우의 문제점을 분석하였다. 그리고, 최적 추정계수 $\^{B}$와 $\^{C}$의 획득 이론과 절차를 전개하고, 제안한 방법의 유효성을 평가하였다. 평가결과, 추정한 $\^{B}$와 $\^{C}$의 측정한 단일 자차를 최적으로 근사할 수 있음을 나타냈다.

• 한국항해항만학회지
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• 제26권1호
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• pp.127-136
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• 2002

항공 대잠수함전에 사용되는 방향주파수분석저장 소노부위 (DIFAR Sonobuoy)에 방위정보를 제공하는 플럭스-게이트 콤파스의 위상감응검출 (PSD) 회로 설계와 구현에 관해서 기술하였다. PSD 회로는 쌍동-T RC 회로망을 갖는 능동형 대역필터로 구성하였다. PSD 회로에 대한 성능실험 결과, 대역통과 필터가 지구자장 방향에 비례하는 2Fe의 2차 고조파 신호를 효과적으로 걸러냄을 확인하였다. 그 결과 방위 신호 정보를 획득할 수 있었다.

• 한국항해항만학회지
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• 제27권4호
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• pp.413-424
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• 2003

이 논문에서 필자들은 유럽과 중국에서 거의 비슷한 시기에 나침반이 항해에 이용되었음을 역사적 기록과 최근까지의 연구성과들을 검토함으로써 밝히고자 하였다. 그 연구 결과는 다음과 같다. 첫째, 동서양 문명권에서 항해자들이 나침반을 항해에 이용하기까지 비슷한 과정을 거쳤다. 즉 표침, 축침, 콤파스 카드 순으로 항해용 나침반을 개발하여 사용하였다. 둘째, Frode의 사가(saga)를 고려해 볼 때 중국과 유럽에서는 11세기 경에 나침반을 항해에 이용하였다. 결론적으로 중국인들이 세계 최초로 나침반을 항해에 이용했다는 기존 주장과는 달리, 중국인들과 유럽인들은 거의 비슷한 시기에 서로 독자적으로 나침반을 항해에 이용하였다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권9호
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• pp.418-423
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• 2003

This paper describes an electronic compass using micromachined X- and Y-axis micro fluxgate sensors which were perpendicularly aligned each other to measure X- and Y-axis magnetic fields respectively. The fluxgate sensor was composed of rectangular-ring shaped magnetic core and solenoid excitation(49 turns) and pick-up(46 turns) coils. Excitation and pick-up coil patterns which were formed opposite to each other wound the magnetic core alternatively to improve the sensitivity and to excite the magnetic core in an optimal condition with reduced excitation current. The magnetic core has DC effective permeability of ~1000 and coercive field of ~0.1 Oe. The magnetic core is easily saturated due to the low coercive field and closed magnetic path for the excitation field. To decrease the difference of induced second harmonic voltages from X- and Y-axis, excitation condition of 2.8 $V_{P-P}$ and 1.2 MHz square wave was selected. Excellent linear response over the range of -100 $\mu$T to +100 $\mu$T was obtained with 210 V/T sensitivity. The size of each micro fluxgate sensor excluding pad region was about 2.6${\times}$1.7 $mm^2$ and the power consumption was estimated to be 14 mW.W.