• 대한전기학회논문지:시스템및제어부문D
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• 제49권1호
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• pp.33-40
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• 2000

In this paper, an integrated method for the path planning and motion control of wheeled mobile robots using a hybrid system model and control is presented. The hybrid model including the continuous dynamics and discrete dynamics with the continuous and discrete state vector is derived for a two wheel driven mobile robot. The architecture of the hybrid control system for real time path planning and following is designed which has the 3-layered hierarchical structure : the discrete event system using the digital automata as the higher process, the continuous state system for the wheel velocity controls as the lower process, and the interface system as the interaction process between the continuous system as the low level and the discrete event system as the high level. The reference motion commands for autonomous navigation are generated by the abstracted motion in the discrete event system. The motion control tasks including the feasible path planning and autonomous motion control with various initial conditions are investigated as the applications by the simulation studies.

• 제어로봇시스템학회논문지
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• 제18권2호
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• pp.149-155
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• 2012

This paper provides an efficient model predictive control for the output voltage control of three-phase inverter system which includes output LC filters. Use of SVPWM (Space Vector Pulse-Width-Modulation) and the rotating d-q frame is made to obtain an input constrained dynamic model of the inverter system. From the measured/estimated output current and reference output voltage, corresponding equilibrium values of the inductor current and the control input are computed. Derivation of a feasible and invariant set around the equilibrium state is made and then a receding horizon strategy which steers the current state deep into the invariant set is proposed. In order to remove offset error, use of disturbance observer is made in the form of state estimator. The efficacy of the proposed method is verified through simulations.

• 한국통신학회논문지
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• 제22권5호
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• pp.1026-1035
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• 1997

본 연구는 RBFN의 일종인 GPFN과 PNN을 이용한 음소인식에 관한 연구이다. RBFN의 구조는 계층형 신경망의 구조와 유사하지만, hidden층에서 활성화함수, 참조벡터 및 학습알고리듬의 선택이 다르다. 특히 PNN은 시그모이드 함수가 지수를 포함한 함수들의 한 분류로 대체된다는 것이며, 학습이 필요없으므로 전체계산 시간이 빠르게 수행된다. 5모음, 12자음을 대상으로 한 음소인식 실험에서 평가데이터, VQ와 LVQ에 의한 코드북 데이터를 사용한 경우에 음성의 통계적 특성을 잘 반영하고 있는 RBFN의 일종인 GPFN과 PNN의 인식결과가 MLP보다 우수하였다.

• 한국통신학회논문지
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• 제33권1C호
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• pp.94-101
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• 2008

본 논문에서는 실시간으로 빛의 편광상태(SOP)를 파악할 수 있는 장치를 소개한다. 소개하는 장치는 광파를 수평 선형편광과 수직 선형편광 성분으로 분리하고, 각각을 기준 광원의 수평 선형편광 및 수직 선형편광 성분들과 중첩시키고 이로부터 발생한 비트신호들을 시간 영역에서 측정하여 비교함으로써 광파의 SOP를 파악해 내는 순방향(feed-forward) 측정 시스템으로서 귀환(feedback) 방식을 이용하는 기존의 방식들에 비해 SOP 측정시간을 실시간으로 단축시키는 장점을 갖고 있다. 본 논문에서는 또한 SOP 측정 과정에서 수반될 수 있는 광소자의 복굴절 변화에 의한 측정 오차를 매우 간편하고 정확하게 제거할 수 있는 새로운 오차 보정 방식을 소개한다. 제안하는 시스템의 동작과 성능을 모의실험 및 광학 실험을 통해 입증하였다.

• 한국정보통신학회논문지
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• 제14권5호
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• pp.1295-1302
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• 2010

본 논문에서는 LVQ(Learning Vector Quantization) 네트워크를 이용한 수신 신호 세기(Received Signal Strength Indication) 기반 실내 위치인식 시스템을 제안하였다. 제안한 방식의 유용성을 확인하기 위하여 실험을 수행하였고, 일반적인 삼각측량 방법과 비교하였다. 실험실을 40개의 영역으로 나누고 6개의 고정 노드를 설치하였다. 무선 채널의 대수-정규 경로 손실 모델을 구성하고, 수신 신호 강도를 거리로 변환하였다. 변환한 정보를 LVQ의 입력으로 사용하였다. LVQ 네트워크의 학습을 위해 영역의 인덱스를 목표값으로 설정하였다. 실험을 통해서 최적의 서브클래스 개수를 결정하였고, LVQ 네트워크의 훈련을 통해서는 96%, 테스트를 통해서는 91%의 성능을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.135-141
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• 2002

This paper presents an implementation of high-dynamic performance of position sensorless motion control system of Reluctance Synchronous Motor(RSM) drives for an industrial servo system with direct torque control(DTC), The problems of DTC for high-dynamic performance and maximum efficiency RSM drive due to a saturated stator linkage flux and nonlinear inductance curve with various load currents, The accurate estimation of the stator flux and torque are obtained using stator flux observer of which a saturated inductance Ld and Lq can be compensated by adapting from measurable the modulus and angle of the stator current space vector. To obtain fast torque response and maximum torque/current with varying load current, the reference command flux is ensured by imposing Ids=Iqs. This control strategy is proposed to fast response and optimal efficiency for RSM drive. In order to prove rightness of the suggested control algorithm, the actual experiment carried out at ${\pm}$20 and ${\pm}$1500 rpm. The developed digitally high-performance control system are shown some good response characteristic of control results and high performance features using 1.0kW RSM of which has 2.57 Ld/Lq salient ratio.

• Journal of Information Processing Systems
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• 제16권1호
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• pp.120-131
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• 2020

In order to solve the problem of point clouds coordinate conversion of non-directional scanners, this paper proposes a basic Rodrigues rotation method. Specifically, we convert the 6 degree-of-freedom (6-DOF) rotation and translation matrix into the uniaxial rotation matrix, and establish the equation of objective vector conversion based on the basic Rodrigues rotation scheme. We demonstrate the applicability of the new method by using a bar-shaped emboss point clouds as experimental input, the three-axis error and three-term error as validate indicators. The results suggest that the new method does not need linearization and is suitable for optional rotation angle. Meanwhile, the new method achieves the seamless splicing of point clouds. Furthermore, the coordinate conversion scheme proposed in this paper performs superiority by comparing with the iterative closest point (ICP) conversion method. Therefore, the basic Rodrigues rotation method is not only regarded as a suitable tool to achieve the conversion of point clouds, but also provides certain reference and guidance for similar projects.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계합동학술대회 논문집
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• pp.112-116
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• 2002

A sensorless control strategy for permanent magnet synchronous motors is presented in this paper. A speed control scheme based on the measurement and observation of stator current, voltage. and flux vector is proposed. Two phase voltages and two stator currents are measured and processed in discrete form in DSP. The rotor position and speed are estimated through the stator flux and its derivative estimation. Flux and its derivative are calculated in the stationary reference frame and used to estimate the speed and position. The rotor position angle is then used in a microcontroller to produce the appropriate stator current command signals for the hysteresis current controller of the inverter. The closed-loop speed control has been shown to be effective from standstill to rated speed. Moreover, a flux drift problem caused by the integration can be eliminated so that a stable sensorless starting and running operation can be achieved. Computer simulation and experimental results are presented to demonstrate the effectiveness of the proposed scheme.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1377-1379
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• 1996

In this paper, each parameter was identified by the gradient descent method to overcome difficulty deciding fuzzy rules of FLC for the unknown process and the type of membership Junctions. Usually PID or optimal control theories have been mostly usee in control field so far. However, optimal control requires much time for calculation because of adaptation for disturbance and nonlinearity. And intricate technique such as MRAS which can be realized only by an expert are limited to be used in the systems requiring rapid and precise response because of comparatively longer calculating time and complicateness. Gradient descent method is a method to find Z minimizing a function about a certain vector Z. And required output of FLC is gained using gradient approaching method in order to adapt control rule parameters of FLC. Simulation proved validation of this algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 에너지변화시스템부문
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• pp.32-34
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• 2009

The field oriented control of induction motors is widely used in high performance applications. However, detuning caused by parameter disturbance still limits the performance of these drives. In order to accomplish variable speed operation, conventional PI-like controllers are commonly used. These controllers provide limited good Performance over a wide range of operation, even under ideal field oriented conditions. This paper is proposed model reference adaptive fuzzy control(MFC) and artificial neural network(ANN) based on the vector controlled induction motor drive system. Also, this paper is proposed control of speed and current using fuzzy adaption mechanism(FAM), MFC and estimation of speed using ANN. The proposed control algorithm is applied to induction motor drive system using FAM, MFC and ANN controller. Also, this paper is proposed the analysis results to verify the effectiveness of this controller.