Decentralized Model Reference Adaptive Control of a Class of Interconnected Continuous Systems

유준,김성수,임인성,Lyou, Joon,Kim, Sung-Soo,Yim, In-Sung The Institute of Electronics and Information Engin 1987 전자공학회논문지 Vol.24 No.6

This paper presents a decentralized model reference adaptive control scheme for an interconnected continuous linear system composed of a number of single input single output subsystems. The scheme can treat the unknown strengh of interconnections as well as the uncertainty of subsystems. The scheme automatically adjusts the local feedback gains so that the output of each subsystem exponetially tracks that of the reference model.

Adaptive Control of Robot Manipulators Using Lyapunov Design

유준,남상우,김병연,박은영,Lyou, Joon,Nam, Sang-Woo,Kim, Byung-Yeun,Park, Eun-Young The Institute of Electronics and Information Engin 1987 전자공학회논문지 Vol.24 No.6

This paper prexents an adaptive control scheme which adjusts any deviations of the manipulator from a desired trajectory. The scheme combines a new adaptive control and the conventional nominal control which drives the manipulator to the neighborhood of the trajectory. The proposed adaptive control is developed based on the lineatized perturbation equations in the vicinity of the trajectory and the Lyapunov design method, which makes the perturbations exponentially decay and has less computational requirements than the existing ones.

GPS/INS 통합시스템의 측정치 시간지연오차 보상

유준,임유철,Lyou Joon,Lim You-Chol 대한전자공학회 2004 電子工學會論文誌-SC (System and control) Vol.41 No.1

INS는 위치, 속도 및 자세정보를 고속으로 제공하며 스스로 항법정보를 제공하는 장점이 있으나 오차가 시간에 따라 증가하는 단점이 있다. 반면에 GPS는 데이터를 저속으로 제공하며 재밍(Jamming)에 영향을 쉽게 받으나 오차가 시간에 상관없이 일정하다는 장점이 있다. 따라서 상호보완적인 특성을 가지는 INS와 GPS를 통합하였을 때 더욱더 정확한 항법해를 제공할 수 있다. 그러나 INS와 GPS를 통합하는 과정에서 INS정보와 GPS정보의 정확한 시각적 동기가 어려우며, 시각적 비동기에 의한 오차는 일정한 측정오차를 유발하며 고속으로 운항하는 경우에는 큰 영향을 미치게 된다. 본 연구는 GPS/INS 통합항법 시스템에서 측정치 시간지연에 의해 유발되는 오차를 효과적으로 줄이기 위해 바이어스 분리형 칼만필터를 이용한 시간지연오차 보상기법을 강결합 방식과 약결합 방식에 대하여 각각 제안하였다. 각각의 통합모델에서 위치와 속도보정의 측정방정식을 지연시간에 관하여 선형화하였고 지연 상태변수를 기존의 선형 오차방정식에 추가하고 바이어스 분리형 칼만필터를 적용하여 시간지연을 초기에 추정하여 보상하도록 구성하였으며 시뮬레이션을 통하여 성능을 검증하였다. The INS(Inertial Navigation System) provides high rate position, velocity and attitude data with good short-term stability while the GPS(Global Position System) provides position and velocity data with long-term stability. By integrating the INS with GPS, a navigation system can be achieved to Provide highly accurate navigation Performance. For the best performance, time synchronization of GPS and INS data is very important in GPS/INS integrated system But, it is impossible to synchronize them exactly due to the communication and computation time-delay. In this paper, to reduce the error caused by the measurement time-delay in GPS/INS integrated systems, error compensation methods using separate bias Kalman filter are suggested for both the loosely-coupled and the tightly-coupled GPS/INS integration systems. Linearized error models for the position and velocity matching GPS/INS integrated systems are Int derived by linearizing with respect to its time-delay and augmenting the delay-state into the conventional state equations for each case. And then separate bias Kalman Inter is introduced to estimate the time-delay during only initial navigation stage. The simulation results show that the present method is effective enough resulting in considerably less position error.

무인기를 위한 광류 실험장치 구현

유준(Joon Lyou),이준민(JunMin Lee),정하형(HaHyoung Jung) 대한전기학회 2015 정보 및 제어 심포지엄 논문집 Vol.2015 No.4

무인기 또는 드론의 호버링시 MEMS 기반의 자세측정센서로는 비행체가 한쪽으로 흐르는 편류현상이 발생한다. 본 연구는 시뮬레이터 개발로, 바닥을 지향한 카메라를 1축 모션 스테이지에 장착하고 일정 속도로 움직임을 인가하여 얻은 영상으로부터 광류 알고리즘을 적용하여 흐르는 방향과 그 양을 구한다. 궁극적으로 광류에 의한 카메라의 움직임을 추정하고 제자리 비행 실현에 유용함을 보인다.

상호 연결된 연속시간 시스템의 비집중 적응 모델 추종 제어

유준(Joon Lyou) 대한전자공학회 1986 대한전자공학회 학술대회 Vol.1986 No.12

야지 자율주행을 위한 환경에 강인한 지형분류 기법

성기열,유준,Sung, Gi-Yeul,Lyou, Joon 한국군사과학기술학회 2010 한국군사과학기술학회지 Vol.13 No.5

This paper presents a vision-based robust off-road terrain classification method against environmental variation. As a supervised classification algorithm, we applied a neural network classifier using wavelet features extracted from wavelet transform of an image. In order to get over an effect of overall image feature variation, we adopted environment sensors and gathered the training parameters database according to environmental conditions. The robust terrain classification algorithm against environmental variation was implemented by choosing an optimal parameter using environmental information. The proposed algorithm was embedded on a processor board under the VxWorks real-time operating system. The processor board is containing four 1GHz 7448 PowerPC CPUs. In order to implement an optimal software architecture on which a distributed parallel processing is possible, we measured and analyzed the data delivery time between the CPUs. And the performance of the present algorithm was verified, comparing classification results using the real off-road images acquired under various environmental conditions in conformity with applied classifiers and features. Experiments show the robustness of the classification results on any environmental condition.

이중 Moving Window 버퍼 기반 전달정렬 측정치 시간지연 보상기법

김천중,유준,Kim, Cheon-Joong,Lyou, Joon 한국군사과학기술학회 2011 한국군사과학기술학회지 Vol.14 No.4

Measurement time delay in the transfer alignment is very important. It has been well known that the time delay degrades the alignment performance and makes some navigation errors on the transfer alignment of slave INS(SINS). Therefore there are many schemes to eliminate that time delay but the compensation technique through the estimation by Kalman filter through modeling the time delay as a random constant is generally used. In the case of change over measurement time delay or the large measurement time delay, estimation performance in the existing compensation technique is degraded because model of time delay is not correct any more. In this paper, we propose the method to keep the time delay almost constant even though in the abnormal communication state and very small through feedback compensation using double buffer. Double buffer consists of two moving window to temporarily store measurements from master INS and slave INS in real time.

측정치 시간지연과 선체의 유연성을 고려한 전달정렬 기법

임유철,유준,Lim, You-Chol,Lyou, Joon 한국군사과학기술학회 2001 한국군사과학기술학회지 Vol.4 No.1

This paper deals with the transfer alignment problem of SDINS(StrapDown Inertial Navigation System) subjected to roll and pitch motions of the ship. Specifically, to reduce alignment errors induced by measurement time-delay and ship body flexure, an error compensation method is suggested based on delay state augmentation and DCM(Direction Cosine Matrix) partial matching. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then DCM partial matching is properly combined to reduce effects of a ship's Y axis flexure. The simulation results show that the suggested method is effective enough resulting in considerably less azimuth alignment errors.

표적추적센서의 측정 바이어스 오차 보상에 의한 사격통제장치 성능 향상 기법

김재훈,유준,Kim, Jae-Hun,Lyou, Joon 한국군사과학기술학회 2000 한국군사과학기술학회지 Vol.3 No.2

A practical method is proposed to improve hit probability of the digital gun fire control system, when the measured rate of the tracking sensor becomes biased under some operational situation. For ground moving target it is shown that the well-known Kalman filter which uses position measurement only can be optimally used to eliminate the rate bias error. On the other hand, for 3D moving aircraft we present a new algorithm which incorporate FIR-type filter, which uses position and rate measurement at the same time, and the fixed-lag smoother using position measurement only, and show that it has the optimal performance in terms of both estimation accuracy and response time.

폐회로 제어시스템의 강인한 고장진단 및 고장허용제어 기법 연구

이종효,유준,Lee, Jong-Hyo,Lyou, Joon 한국군사과학기술학회 2000 한국군사과학기술학회지 Vol.3 No.1

This paper presents a robust fault diagnosis and fault tolerant control method for the control systems in closed-loop affected by unknown inputs or disturbances. The fault diagnostic scheme is based on the disturbance-decoupled state estimation using a 2-stage state observer for state, actuator bias and sensor bias. The estimated bias show the occurrence time, location and type of the faults directly. The estimated state is used for state feedback to achieve fault tolerant control against the faults. Simulation results show that the method has definite fault tolerant ability against actuator and sensor faults, moreover, the faults can be detected on-line, isolated and estimated simultaneously.