• 전자공학회논문지
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• 제52권5호
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• pp.190-196
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• 2015

본 논문은 항법장치 위치보정을 위해 칼만필터를 적용한 GPS/INS융합의 다중보정방법을 제안한다. 연구에서는 관성항법장치를 구현하기 위해 9축 항법장치로 보정알고리즘을 적용하여 위치오차를 감소시킨 방법을 적용했다. 일반적으로 GPS/INS는 위치정보를 얻어낼 수 있지만 위치정보를 구하는 과정에서 오차 또한 더불어 커지게 되기에 이를 보정하기 위한 강인한 오차 보정 알고리즘이 필요하다. 본 논문에서는 9축 관성센서(mpu-9150)의 외란에 대한 강인성 향상을 위해 가속도계 보정 알고리즘을 사용하여 tilt보정을 수행했으며, 제어 대상체의 정확한 방위를 파악할 수 있도록 Yaw각 재정의 알고리즘을 적용하였다. 최종적으로 GPS/INS와 칼만 필터를 함께 결합한 통합시스템을 구현하였다.

• 정보저장시스템학회논문집
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• 제7권1호
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• pp.19-24
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• 2011

Holographic Data Storage System, one of the next generation data storage devices, is a 2-dimensional page oriented memory system using volume holograms in writing and retrieving process. Recently photopolymer with disc type substrate was selected as a media for the Holographic Data Storage System. The disc tilt occurs when the media rotates and the external disturbance applies. The disc tilt causes the change of the angle between the reference beam and the media, the data cannot be retrieved with the right angle or other data page is retrieved. The tilt is generated in a 2-axis direction (tangential, radial). The tangential tilt direction is the same with the multiplexing plane, while the radial tilt direction is a perpendicular to the multiplexing plane. In this research we propose 2-axis tilt angle servo system. The tilt errors are measured by using external photo detector and the additional red laser. Then the tangential direction tilt is compensated by using the galvano mirror. Also the radial direction tilt is compensated by the rotating prism between the relay lens in the reference field. Finally we confirm the compensation results through the Signal to Noise Ratio(SNR) and Bit Error Rate(BER).

• 제어로봇시스템학회논문지
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• 제20권2호
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• pp.149-156
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• 2014

A magnetic compass module must be calibrated accurately before use. Moreover, the calibration process must be performed taking into account any magnetic dip if the magnetic compass module has tilt angles. For this, a calibration method for a magnetic compass module is explained. Tilt error of the magnetic compass module is compensated using a biaxial accelerometer generally. The accelerometer error causes a tilt angle calculation error that gives rise to an azimuth calculation error. For error property analysis, error equations are derived and simulations are performed. In the simulation results, the accuracy of derived error equations is verified. If a biaxial magnetic compass module is used instead of a triaxial one, the magnetic dip and z-axis magnetic compass data must be estimated for tilt compensation. Lastly, estimation equations for the magnetic dip and z-axis magnetic compass data are derived, and the performance of the equations is verified based on a simulation.

• ETRI Journal
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• 제27권3호
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• pp.280-288
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• 2005

This paper presents an efficient algorithm for using the two-axis magnetic compass in portable devices. The general magnetic compass module consists of a three-axis magnetic compass and a two-axis inclinometer to calculate tilt-compensated azimuth information. In this paper, the tilt error is compensated using just a two-axis magnetic compass and two-axis accelerometer. The third-axis data of the magnetic compass is estimated using coordinate information that includes the extended dip angle and tilt information. The extended dip angle is estimated during the normalization process. This algorithm can be used to provide the tilt-compensated heading information to small portable devices such as navigation systems, PDAs, cell phones, and so on.

• 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.

• 전자공학회논문지 IE
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• 제49권2호
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• pp.9-17
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• 2012

음성 인식 시스템의 용용에서 실제 문제점의 하나는 음성신호의 왜곡에 의한 인식성능의 저하이다. 음성신호의 왜곡에 가장 중요한 원인은 부가적인 잡음이다. 이 논문은 잡음에 강인한 음성인식을 위하여, 스펙트럼 피크 향상 기법과 효과적인 잡음 차감 기법에 기초한 스펙트럼 보상 방법을 기술한다. 제안한 방법은 음성 스펙트럼의 포먼트 구조를 향상시키고 스펙트럼 기울기를 보상하면서도 광 대역폭 스펙트럼 요소는 그대로 유지한다. 백색 가우스 잡음, 자동차 잡음, 음성 잡음 또는 지하철 잡음에 의해 왜곡된 음성을 이용한 인식실험을 수행한 결과, 새로운 방법은 스펙트럼 보상을 하지 않은 경우에 비해, 높은 SNR(Signal to Noise Ratio) 환경에서는 평균 오인식율을 약간 줄였으며, 낮은 SNR(10 dB) 환경에서는 평균 오인식율을 1/2로 크게 줄였다.

• 소음진동
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• 제10권4호
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• pp.584-595
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• 2000

We design a new actuator for high density optical device in order to control the radial tilting motion. The newly designed actuator makes it possible to control the tilting motion actively, while the coventional actuator compress tilting motion with passive spring. First of all, We present 3-dimensional modeling of actuator and accomplish the modal analysis and magnetic analysis of actuator. Due to these results, a new designed actuator has performance of high sensitivity and high second resonance frequency. Secondly, We present the 3-DOF dynamic modeling of the 4-wire spring type actuator. sensitivity analysis is performed to consider the assembling error, such as the difference of mass center and force center. From these results, the sensitivities of rotation due to the assembly error are revealed and design criteria of rotation is presented. And experimental results of a newly designed actuator are presented and compared with theoretical results. Finally, We propose a dynamic tilt compensation and high acceleration actuator for high density optical storage devices.

• Journal of Magnetics
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• 제21권4호
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• pp.524-528
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• 2016

Eddy current (EC) sensor works based on the electromagnetic induction principle and has been widely applied in the industrial testing and evaluation due to its robustness and environmental adaptability. Meanwhile, tilt angle measurement is mainly based on the laser or visual method, which is strict with the measurement environment and not suitable for the industrial applications. In this paper, a novel tilt angle measurement method based on arrayed EC sensors is proposed. Both the simulation and experiments indicate that the measured error is approximately linear with tilt angle and the accuracy after compensation is $0.25^{\circ}$. In conclusion, this research cannot only broaden the scope of EC application, but also overcome the shortcomings of existing angle measurement methods.

• 한국정밀공학회지
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• 제17권10호
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• pp.147-154
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• 2000

A new hardware compensation method reducing displacement measurement errors, caused by tilt of index scale in moire linear encoders, has been developed. In conventional moire linear encoders, the detectors are aligned perpendicular to the line of moire fringes this structure is very sensitive to an unwanted tilt of the gratings. In this paper, a newly designed grating, called a phase-modulated grating, is developed to compensate for non-orthogonal errors. By using the phase-modulated grating instead of a conventional index, it is possible to reduce non-orthogonal errors of moire linear encoders.

• 전자공학회논문지SC
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• 제48권1호
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• pp.1-8
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• 2011

MR 센서에 의해 지구자기장의 세기를 측정하여 방위각을 결정하는 전자 Compass의 정밀도는 MR센서 및 OP-Amp.의 온도 Drift, DC Offset등 소자에 의한 오차, 측정주변 자성체에 의한 자기장의 왜곡, 및 Compass Tilt에 의한 오차 등의 영향을 받는다. 본 연구에서는 Set/Reset Pulse 방법에 의해 MR 센서 및 OP-Amp의 온도 Drift 및 DC Offset에 의한 오차를 해결하였고, 주변 자성체에 의한 자기장의 왜곡에 의한 오차를 Hard-Iron Calibration 루틴 수행에 의해 보상하였으며, Compass Tilt에 의한 오차를 Euler Rotational Equation에 의해 보상할 수 있는 3축 MR 센서 및 3축 Accelerometer를 기반으로 하는 전자 Compass 를 설계하였다. 특히 이와 샅이 설계한 전자 Compass를 가지고 3측 MR 센서의 서로 다른 Sensitivity와 OP-Amp.의 서로 다른 Gain등을 규준화하기 위한 Sensitivity Calibration 루틴 수행 시 Tilt의 발생으로 야기되는 오차를 정량적으로 분석하였으며, 이를 바탕으로 $1^{\circ}$정도(精度) Compass를 설계할 수 있었다.