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Development of Real-time Heading Estimation Algorithm using Magnetometer/IMU
Wonmo Koo,Sangkyung Sung,Young Jae Lee 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
This paper presents a real-time heading estimation algorithm using IMU and strapdown magnetometerwithout any other external heading reference system. To calibrate the output deviation of magnetometer, sensor errors caused by hard, soft iron effect and initial heading of strapdown magnetometers are considered. First, for the estimationof heading angle, system and measurement model is derived, which reveals to be nonlinear. Then particle filter and extended Kalman filter is introduced for the performance comparison. The proposed algorithm for the integration ofIMU and magnetometer is verified via numerical simulation in Matlab. Simulation result demonstrates accurate headingestimation error less than 1 degree for both algorithms when there exist small initial heading error and hard iron effect,yet particle filter provides more robust and precise result than the extended Kalman filter in case the initial heading errorand biases are large.
Koo Wonmo,Lee Joohyun,Ryu Myungseok 대한침도의학회 2023 대한침도의학회지 Vol.7 No.1
Background: The aim of this study is to report the improved case with acupotomy and acupuncture treatment on Mild Cognitive Impairment (MCI). Methods: One patient with mild cognitive impairment was treated with acupotomy and acupuncture. Mini-Mental State Examination-Korean (MMSE-K) and Subject Memory Complaints Questionnaire (SMCQ) were used to evaluate the effect of the treatment. Results: In the case, MMSE-K score maintainted over 23 during treatment and SMCQ score was declined from 11 to 5 after 2 acupotomy treatments and 3 acupuncture treatments. Conclusion: These results suggest acupotomy and acupuncture treatment can be effective for mild cognitive impairment patients on not only preventing conversion to dementia but also improving memory complaints.
Error Calibration of Magnetometer Using Nonlinear Integrated Filter Model With Inertial Sensors
Wonmo Koo,Sangkyung Sung,Young Jae Lee IEEE 2009 IEEE transactions on magnetics Vol.45 No.6
<P>This paper presents an onboard heading estimation algorithm using IMU and strapdown magnetometer without other external heading references. To calibrate the magnetic deviation, sensor errors caused by hard iron effect and initial heading of strapdown magnetometers are considered. In our approach, sensor output distortion due to the soft iron effect is ignored, which is relatively small. First, for the estimation of heading angle, system and measurement model is presented. Then particle filter and extended Kalman filter is introduced for performance comparison. The proposed algorithm for the integration of IMU and magnetometer is verified via numerical simulation using Matlab. Simulation result demonstrates accurate heading estimation error under 1 degree for both algorithms when there exists a small initial heading error and hard iron effect, yet particle filter provides more robust and accurate result than the extended Kalman filter in case the initial heading error and biases are large.</P>
저가형 GPS/IMU를 이용한 UAV 비행 제어 시스템 개발
구원모(Wonmo Koo),천세범(Sebum Chun),원대희(Dae Hee Won),강태삼(Taesam Kang),이영재(Young Jae Lee),성상경(Sangkyung Sung) 제어로봇시스템학회 2008 제어·로봇·시스템학회 논문지 Vol.14 No.5
UAVs(Unmanned Aerial Vehicles) have many applications in military and commercial areas. The flight control system of UAVs is more important than manned aircraft"s because the mission of UAVs must be operated without a human pilot. But very heavy and expensive navigation system makes it difficult to develop UAV flight control system. In this research, GPS/IMU integrated navigation filter was developed for light weight/low cost flight control system of small UAVs. With this navigation filter, full flight control system which has real time operating capability has been developed. The performance of the flight control system is basically checked by HILSIM (Hardware In the Loop SIMulation). Finally, the flight control system is verified by showing performance test result under real flight environment.
구원모(Wonmo Koo),이창진(Changjin Lee) 한국추진공학회 2007 한국추진공학회지 Vol.11 No.4
The irregular fuel surface was observed by the visualization of hybrid rocket combustion. Even though the test condition maintained oxidizer rich environment, the irregular dark fuel surface was formed as the result of incomplete combustion. In order to investigate the correlation of the characteristics of oxidizer flow and the irregular fuel surface, various flow conditions were imposed such as swirl flow, induced swirl flow by helical fuel configuration and straight flow. Test results revealed no correlation was found between oxidizer flow condition and irregular fuel surface. And this can be a commonly observed phenomena in the tests with different fuel/oxidizer combination. Thus, the irregular fuel surface can be a result of the interaction of blowing flow of vaporized fuel and the boundary layer of oxidizer flow. A further study will be required to confirm the assumption for the formation of irregular fuel surface.