• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2015.07a
• /
• pp.507-508
• /
• 2015

본 논문에서는 알 수 없는 주파수의 정현파외란(sinusoidal disturbance)을 가지는 선형시불변(linear time-invariant) 시스템에 대해 그 외란의 주파수 추정과 억제를 목표로 하는 알고리즘을 설계한다. 제시된 알고리즘은 주파수 추정을 위한 적응관측기(adaptive observer)와 외란 제거를 위한 출력조정기(output regulator)로 구성된다. 기존에 연구에 비하여 모델불확실성에 대한 강인성은 유지하면서 제어기의 초기값(initial value) 설정에 의존하지 않는 안정도 및 성능을 가진다. 제안된 알고리즘은 외란의 주파수를 완벽하게 추정하며, 그 정보를 바탕으로 외란 제거 성능을 보장할 수 있다. 또한, 실제 광디스크 시스템(optical disc drive systems)에 대한 시뮬레이션을 통하여 그 효과를 보여준다.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.53 no.6
• /
• pp.395-401
• /
• 2004

By using an adaptive algorithm, together with an additional dynamic system, this paper proposes a new approach to design of a state observer for a class of uncertain systems. We enlarge the class of linear systems from the canonical form of [1] by proposing an adaptive observer that allows unknown parameters to affect those unmeasured states. The result is based on a recent result which presents a design algorithm for an additional system to replace output derivative measurements with the additional dynamics. A numerical example illustrates the design procedure of the state observer.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.50 no.2
• /
• pp.80-86
• /
• 2001

We design a sliding mode cascade observer to estimate derivatives of the output. In the 1st step of the observer, the output will be estimated, and the 1st order derivative of the output will be estimated via the 2nd step of the observer. Also, nth order derivative of the output will be estimated in the n+1th step of the observer. Exponential convergence of the estimation errors is shown under the bounded initial condition. Numerical examples will be presented to show the validity of the proposed observer.

• Proceedings of the KIPE Conference
• /
• 2007.07a
• /
• pp.369-371
• /
• 2007

Due to the measurement noise or system noise, the performance of photovoltaic power generation system can be degraded. If this noise is contained in the solar array voltage measurement signal, the correct operation of the maximum power point tracker can not be guaranteed. The application of the extended Kalman filter to the photovoltaic system can obtain enhanced states estimation result. The Kalman filter provides a recursive solution to optimally estimate from random noise signals. Additionally, as a consequence of Kalman filter, the unmeasurable state such as inductor current can be estimated without current sensor. The methods for system modeling and extended Kalman filter design are presented and the experimental results verify the validity of the proposed system.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.1149-1151
• /
• 1996

In the last several years, considerable attention has been focused on the problem of designing observers for linear systems with unknown inputs. Since UIO(unknown inputs observer) has the derivative of the outputs, it is very sensitive to measurement noises. Therefore this note propose an algebraic approach to UIO design to alleviate the prescribed problems. Since the proposed method has simple form to estimate state and unknown input and robustness to sensor noise, we believe that it is very attractive in practice.

• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.1138-1141
• /
• 2003

This paper proposes a new speed and flux estimation method which has the robustness against the variation of the electrical parameters of the motor and the superiority in the dynamic characteristics compared with the conventional sensorless schemes. In the proposed method, the stator currents and the rotor fluxes are observed on the stationary reference frame using the sliding mode concept. And the rotor speed is estimated using the current estimation errors and the observed rotor fluxes based on the Lyapunov stability theory. Also a design method of the observer gain is proposed to minimize the effect of the speed estimation error on the rotor flux observation. The experimental results verified that the proposed method shows more robust and improved performances than the previous estimation method under the variations of motor resistance and inductance.

• Proceedings of the KIEE Conference
• /
• 2003.07d
• /
• pp.2046-2048
• /
• 2003

In this paper, a neural disturbance observer(NDO) is developed and its application to the control of a nonlinear system with the internal and/or external disturbances is presented. To construct the NDO, a parameter tuning method is proposed and shown to be useful in adjusting the parameters of the NDO. The tuning method employes the disturbance observation error to guarantee that the NDO monitors unknown disturbances. Each of the nodes of the hidden layer in the NDO network is a radial basis function(RBF). In addition, the relationships between the suggested NDO-based control and the conventional adaptive controls reported in the previous literatures are discussed. And it is shown in a rigorous manner that the disturbance observation error converges to a region of which size can be kept arbitrarily small. Finally, an example and some computer simulation results are presented to illustrate the effectiveness and the applicability of the NDO.

• Proceedings of the KIEE Conference
• /
• 1993.07a
• /
• pp.296-298
• /
• 1993

In this paper, a new design procedure is proposed for constructing the observer for linear discrete-time systems with unknown inputs. An existence condition for the suggested observer is also presented. The observer design procedure does not use any transformation technique, augmentation technique and has a clear physical meaning, so it is easy to understand and to design the observer. It directly estimates the unknown inputs from that outputs only, so it is different from other pre-works in which the reconstruction of the unknown inputs arc performed with the additional output derivatives.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.5
• /
• pp.751-754
• /
• 2015

This paper deals with a robust speed control problem of a vertical one-link manipulator in the presence of parameter uncertainties and unknown input disturbance. Uncertain load weight causes an additional sinusoidal disturbance in the rotation of the link. In order to improve the robustness against parameter uncertainties and external input disturbances, this paper employs an internal model-based disturbance observer approach. Comparative computer simulations are performed to test the performance of the proposed controller. The simulation results show the enhanced performance of the proposed method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.16 no.6
• /
• pp.80-86
• /
• 2002

In this paper, we present a method of fuzzy controller design for the power plant superheater in the form of bilinear system. For the steam temperature control, the input variables are constructed by the area of difference between the profiles estimated from bilinear observer and reference profiles, and the time rate of change. We estimate the control rules by T. Takagi and M. Sugeno's fuzzy model. The feasibilities of the suggested method are illustrated via the computer simulation results.