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주행거리계의 기구적 오차에 강인한 개선된 상대 위치추정 알고리즘
나원상(Won-Sang Ra),황익호(Ick-Ho Whang),이혜진(Hye-Jin Lee),박진배(Jin Bae Park),윤태성(Tae-Sung Yoon) 제어로봇시스템학회 2008 제어·로봇·시스템학회 논문지 Vol.14 No.9
In this paper, a novel localization algorithm robust to the unmodeled systematic odometry errors is proposed for low-cost non-holonomic mobile robots. It is well known that the most pose estimators using odometry measurements cannot avoid the performance degradation due to the dead-reckoning of systematic odometry errors. As a remedy for this problem, we try to reflect the wheelbase error in the robot motion model as a parametric uncertainty. Applying the Krein space estimation theory for the discrete¬time uncertain nonlinear motion model results in the extended robust Kalman filter. This idea comes from the fact that systematic odometry errors might be regarded as the parametric uncertainties satisfying the sum quadratic constrains (SQCs). The advantage of the proposed methodology is that it has the same recursive structure as the conventional extended Kalman filter, which makes our scheme suitable for real-time applications. Moreover, it guarantees the satisfactory localization performance even in the presence of wheelbase uncertainty which is hard to model or estimate but often arises from real driving environments. The computer simulations will be given to demonstrate the robustness of the suggested localization algorithm.
선배열 마이크를 이용한 강인 도래각 추정기법 및 인지로봇 청각시스템 응용
나원상(Won-Sang Ra),한슬기(Seul-Ki Ha),주영은(Young Eun Joo),김영하(Yeongha Kim),이혜경(Hye-Kyung Lee) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
An efficient and practical DOA(direction of arrival) estimator using linear microphone array is proposed for developing cognitive robot ear. In the derivation of the acoustic signal measurement model for DOA estimation, the stochastic parameter uncertainty is inevitably included in the measurement matrix which causes the degradation of the estimation performance. As a remedy for this problem, the recently proposed robust least squares(RoLS) [1] can be used for DOA and frequency estimation. In spite of using the noisy measurement matrix, the estimation performance of the proposed scheme is by no means inferior to that of the optimal least squares-based method which cannot be realizable in actual situations. Simulation results show the superiority of the proposed method in estimation performance and computational efficiency.
나원상(Ra, Won-Sang) 대한전기학회 2023 전기의 세계 Vol.72 No.1
차량용 고해상도 레이더는 향상된 각도해상도와 우수한 탐지 성능으로 인해 자율주행차 인지 시스템의 신뢰성 확보에 중요한 역할을 할 것으로 예상된다. 고해상도 레이더의 저수준 데이터는 많은 표적 정보를 포함하고 있지만, 이를 표적 탐지/추적에 활용하는 데에는 여러 기술적 어려움이 뒤따르는 것으로 알려져 있다. 본고에서는 독자들이 차세대 주행환경 인지 시스템의 연구방향을 모색할 수 있도록, 고해상도 레이더 기술동향과 연구사례를 소개한다. High-resolution radar(HRR) has improved angular resolution and superior detection performance, which is expected to play an important role in securing reliability of the automotive perception system. An HRR is advantageous for acquiring plenty of target information, but there are many practical difficulties in implementing the target detection and tracking algorithm using it. To help readers’ future research on the automotive perception system, this review introduces the recent research trend and case strudies associated with HRRs.
나원상(Won-Sang Ra),신효상(Hyo-Sang Shin),정보영(Bo-Young Jung),황익호(Ick-Ho Whang) 대한전기학회 2019 전기학회논문지 Vol.68 No.1
This paper deals with the problem of generating the energy optimal trajectory which is intended to enhance the target tracking performance of a passive homing missile. Noticing that the essence of passive target tracking is the range estimation problem, the target information gathered by passive measurements can be readily analyzed by introducing the range estimator designed in line-of-sight(LOS) frame. Moreover, for the linear filter structure of the suggested range estimator, the cost function associated with the target information is clearly expressed as a function of the line-of-sight rate. Based on this idea, the optimal missile trajectory maximizing the target information is obtained by solving the saddle point problem for an indefinite quadratic cost which consists of the target information and the energy. It is shown that, different from the previous heuristic approaches, the guidance command producing the optimal passive homing trajectory is produced by the modified proportional navigation guidance law whose navigation constant is determined by the weighting coefficient for target information cost.