• Title/Summary/Keyword: nonlinear adaptive control

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Improved extended kalman filter design for radar tracking

  • Park, Seong-Taek;Lee, Jang-Gyu
    • 제어로봇시스템학회:학술대회논문집
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    • 1996.10a
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    • pp.153-156
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    • 1996
  • A new filtering algorithm for radar tracking is developed based on the fact that correct evaluation of the measurement error covariance can be made possible by doing it with respect to the Cartesian state vector. The new filter may be viewed as a modification of the extended Kalman filter where the variance of the range measurement errors is evaluated in an adaptive manner. The structure of the proposed filter allows sequential measurement processing scheme to be incorporated into the scheme, and this makes the resulting algorithm favorable in both estimation accuracy and computational efficiency.

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Periodic Disturbance Cancellation by using Dual-Input Describing Function (DIDF) Method (DIDF 방법을 이용한 주기성 외란의 제거)

  • Choe, Yeon-Wook;Lee, Hyung-Ki
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.1
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    • pp.168-175
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    • 2010
  • The issue of rejecting periodic disturbances arises in various applications dealing with rotating machinery. A new method using DIDF (Dual-Input Describing Function) is presented for the rejection of periodic disturbances with uncertain frequency. This can be added to an existing feedback control system without altering the closed-loop system stability. The objective is to design a nonlinear compensator to secure specified oscillation amplitude and frequency which are the same as disturbances. We suggest two procedures to determine coefficients for DIDF's synthesis. The structure of the proposed DIDF is so simple that we can easily synthesize. A number of computer simulations were carried out to demonstrate the salient feature of the proposed DIDF compared to the conventional ones(that is, adaptive algorithms).

Frequency Stabilization of a Nonlinear Two-Generator Five-Bus Power System using Adaptive Fuzzy Control (퍼지 적응 제어를 이용한 전력게통 주파수 안정화의 비선형 2기 5모선 모의 적용)

  • Moon, Un-Chul
    • Journal of KIISE:Software and Applications
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    • v.27 no.9
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    • pp.952-960
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    • 2000
  • 본 논문에서는 퍼지 자동회귀 이동평균 (Fuzzy Auto-Regressive Moving Average, FARMA)제어기를 전력계통의 비선형 2기 5모선 (Two Machine - Five Bus)모형의 주파수 안정화에 적용한 결과를 제시한다 퍼지 자동회귀 이동 평균 제어기는 기존의 전문가에 의존하였던 퍼지제어 규칙을 실시간으로 형성해 나가는 구조이다. 복잡성, 비선형성 등 전력계통의 일반적인 특징들을 기술하고, 그 특징을 표현할 수 있는 비선형 2기5모선 모형을 제시한다. 제시된 모형을 바탕으로 기존 제어 방식과의 성능 비교를 실시하였고, 이를 통하여 FARMA 제어기의 우수성을 확인하였다.

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Deadzone Compensation of Positioning Systems using Fuzzy Logic

  • Minkyong Son;Jang, Jun-Oh;Lee, Pyeong-Gi;Park, Sang-Bae;Ahn, In-Seok;Lee, Sung-Hwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.102.4-102
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    • 2002
  • A deadzone compensator is designed for a positioning system using fuzzy logic. The classification property of fuzzy logic systems make them a natural candidate for the rejection of errors induced by the deadzone, which has regions in which it behaves differently. A tuning algorithm is given for the fuzzy logic parameters, so that the deadzone compensation scheme becomes adaptive, guaranteeing small tracking errors and bounded parameter estimates, formal nonlinear stability proofs are given to show that the tracking error is small. The fuzzy logic deadzone compensator is implemented on a positioning system to show its efficacy. 1. Deadzone Compansation 2. XY positioning table 3. Fuzzy Logic 4. Actuator nonlinearity

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Self-tuning of PID controller using diagonal recurrent neural networks (Diagonal 리커런트 신경망을 이용한 PID 제어기의 자기동조)

  • Shin, Jong-Wook;Chai, Chang-Hyun;Kim, Sang-Hee;Choi, Han-Go
    • Proceedings of the KIEE Conference
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    • 1997.07b
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    • pp.609-611
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    • 1997
  • In this paper, we propose the self-tuning of PID controller using diagonal recurrent neural networks. The characteristic of the proposed structure is on-line adaptive learning scheme in spite of variations of feedback, signals. Control performance is compared with that of neural network based PID controller which was proposed by Iwasa. Computer simulation results show that the proposed controller is effective in controlling of unknown nonlinear plants.

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Construction of Adaptive Fuzzy Controller with Neural Network Architecture (신경회로망 구조를 가진 적응퍼지제어기의 구축)

  • 홍윤광;조성원
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1996.10a
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    • pp.249-252
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    • 1996
  • Fuzzy logic has been successfully used for nonlinear control systems. However, when the plant is complex or expert knowledge is not available, it is difficult to construct the rule bases of fuzzy systems. In this paper, we propose a new method of how to construct automatically the rule bases using fuzzy neural network. Whereas the conventional methods need the training data representing input-output relationship, the proposed algorithm utilizes the gradient of the object function for the construction of fuzzy rules and the tuning of membership functions. Experimental results with the inverted pendulum show the superiority of the proposed method in comparison to the conventional fuzzy controller.

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Parameter Identification of Nonlinear Systems using Hopfield Network (Hopfield 신경망에 의한 비선형 계통의 파라미터 추정)

  • Lee, Kee-Sang;Park, Tae-Geon;Ham, Jae-Hoon
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.710-713
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    • 1995
  • Hopfield networks have been applied to the problem of linear system identification. In this paper, Hopfield network based parameter identification scheme of non-linear dynamic systems is proposed. Simulation results demonstrate that Hopfield network can be used effectively for the identification of non-linear systems assuming that the system states and their time derivatives are available. Therefore, the proposed scheme can be applied in fault detection and isolation(FDI) and adaptive control of non-linear systems where the Hopfield networks perform on-line identification of system parameters.

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Continuous-Time Controller Design using Identification of Feedback System in Frequency Domain (주파수역 피드백시스템인식을 이용한 연속시간 제어기 설계)

  • Yang, Ho-Suk;Jung, Yu-Chul;Lee, Gun-Bok
    • Proceedings of the KSME Conference
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    • 2001.06b
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    • pp.664-669
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    • 2001
  • Continuous-time controller design is proposed using feedback system identification in frequency domain. System stability imposed by a new controller is checked in the function of a conventional closed-loop system, instead of a poorly modeled plant due to non-linearity and disturbance as well as unstable components, etc. The stability of the system is evaluated in view of Nyquist stability. All the equations are formulated in the framework of the discrete-time system. Simulation results are shown on the plant with input saturation and DC disturbance.

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Wavelet Network for Stable Direct Adaptive Control of Nonlinear Systems (비선형 시스템의 안정한 직접 적응 제어를 위한 웨이브렛 신경회로망)

  • 서승진;연정흠;전홍태
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.10a
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    • pp.317-323
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    • 1998
  • 이 논문에서는 웨이브렛 신경회로망을 사용하여 알려지지 않은 비선형 시스템을 안정하게 적응제어하는 문제를 다룬다. 비선형 시스템의 정확한 제어는 함수를 근사화하는 데 사용된 함수 근사화기의 정확성과 효율성에 의존한다. 이에 비선형 시스템 제어에 기준 함수의 선택이 자유롭고 함수 근사화 능력이 뛰어난 웨브렛 신경회로망을 사용한다. 초기 웨이브렛 신경회로망 제어기 설정은 웨이브렛 신경회로망 변수인 신축과 이동 값을 제어기 입력의 시-주파수 특성을 분석해서 구하고, 연결강도는 Lyapunov 안정성 이론에 기초한 적응 법칙을 사용하여 조절한다. 이를 비선형 시스템인 역 진자 시스템에 적용한다.

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A Study on the Vehicle Dynamics and Road Slope Estimation (차량동특성 및 도로경사도 추정에 관한 연구)

  • Kim, Moon-Sik
    • Journal of the Korean Society of Industry Convergence
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    • v.22 no.5
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    • pp.575-582
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    • 2019
  • Advanced driving assist system can support safety of driver and passengers which may require vehicle dynamics states as well as road geometry. It is essential to have in real-time estimation of related variables and parameters. Among the road geometry parameters, road slope angle which can not be measured is essential parameter in pose estimation, adaptive cruise control and others on sag road. In this paper, Kalman filter based method for the estimation of the vehicle dynamics and road slope angle using a nonlinear vehicle model is proposed. It uses a combination of Kalman filter as Cascade Extended Kalman Filter. CEKF uses measured vehicle states such as yaw rate, longitudinal/lateral acceleration and velocity. Unknown vehicle parameters such as center of gravity and inertia are obtained by 2 D.O.F lateral model and experimentally. Simulation and Experimental tests conducted with commercialized vehicle dynamics model and real-car.