• 전자공학회논문지C
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• 제35C권8호
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• pp.68-74
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• 1998

The neural network predictiv econtroller (NNPC) is proposed for the attempt to mimic the function of brain that forecasts the future. It consists of two loops, one is for the prediction of output (NNP:neural network predictor) and the other one is for control the plant(NNC: neural network controller). The output of NNC makes the control input of plant, which is followed by the variation of both plant error and predictin error. The NNP forecasts the future output based upon the current control input and the estimated control output. The input and the output data of a system and a new method using evolution strategy are used to train the NNP. A two-step NNPC is applied to control the temeprature in boiler systems. It was compared with PI controller and auto-tuning PID controller. The computer simulaton and experimental results show that the proposed method has better performances than the other method.

• 한국전자통신학회논문지
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• 제19권5호
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• pp.853-860
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• 2024

본 연구에서는 최근, 산업 전자 기기에서 요구되는 다중 출력 전압을 가지는 PWM 제어 기반 단일 입력/단일 출력 강압형 DC-DC 컨버터 설계 방법을 연구하였다. 강압형 DC-DC 컨버터의 기본 이론을 기반으로 강압형 컨버터의 설계 방법을 결정하였고 다중 레벨의 출력 전압을 선택적으로 얻을 수 있는 단일 입력, 단일 출력 강압형 컨버터에 대한 PWM 제어 기반의 전압 제어 알고리즘을 개발하였다. 설계 방법론의 유효성을 검증하기 위해 하나의 시작품을 설계, 시험 제작하였다. 다음, 시작품을 기반으로 하는 시험 환경 하에서, 고정 입력 전압과 가변 입력 전압에 대해 목표 전압들이 선택적으로 결정될 때 다중 출력 전압들이 목표 전압들을 오차율 7%이내에서 추종하는 것을 확인함으로써 PWM 제어 기반의 전압 제어 방법의 유효성을 검증할 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1496-1499
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• 1996

A nonlinear tracking control technique developed for the control of nonlinear systems has been applied to the autopilot design of missile system. The difficulties in the application of inversion based control methods such as input-output feedback linearization and sliding mode control due to nonminimum phase characteristics are discussed. To avoid the stability problem associated with unstable zero dynamics, the input-output feedback linearization is applied with output-redefinition method to normal acceleration control. The output-redefinition method gives an indirect way to apply the nonlinear controls to nonminimum phase plants by redefining the plant output such that the tracking control of the modified output ensures the asymptotic tracking of the original output. The numerical simulation shows satisfactory results both for nominal and for slightly perturbed missile systems adopting the sliding mode control technique. However, the robustness problem in this method is briefly investigated and verified with the simulation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.301-305
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• 2005

This paper introduces a novel technique to detect and isolate the failures of multiple actuators connected to a system. Failure of actuator considered in this study could be any type of erroneous input that is different from commanded one. The interaction matrix technique allows the development of input-output equations that are only influenced by one target input. These input-output equations serve as an effective toot to monitor the integrity of each actuator regardless of the status of the other actuators. The method is capable of real-time actuator failure detection and isolation under any type of input excitation. The laboratory experiment using 8-bay NASA truss structure verifies the feasibility of the proposed method.

• 한국지역지리학회지
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• 제8권4호
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• pp.480-491
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• 2002

본 연구의 목적은 정보가 계약된 조건하에서의 다지역에 대한 지역간 산업연관표를 작성하고 이에 대한 정확성을 평가하는 데 있다. 지역간 산업연관표의 작성 방법은 이미 지난 1950년대 초 Isard 및 Leontief 등에 의하여 개발된 이 후 다양한 기법들이 제시되어왔다. 이들 기법 중에서 정확성 면에서는 실제 조사를 통하여 지역간 산업연관표를 작성하는 것이 가장 바람직하지만, 이 경우 많은 시간과 경비를 부담해야만 하는 현실적 어려움이 수반된다. 따라서 은 연구에서는 정보, 특히 지역수준에서 최종수요 및 지역간 상품의 흐름에 대한 정보가 제약된 조건하에서 우리나라의 전국을 5개 지역으로, 그리고 전 산업을 13개 부문으로 구분하여 비조사방법에 의하여 지역간 산업연관표를 작성하였다. 비조사방법에 의하여 지역간 산업연관표를 작성하는 방법에도 여러 가지가 있지만, 본 인구에서는 기본적인 LQ 기법을 원용하여 이를 다지역 모형으로의 확장을 시도하였다. 끝으로 추정된 투입계수의 정확성을 평가하기 위하여, 특정 지역 투자의 지역 및 지역간 파급효과를 분석하고, 이를 기존의 실제 조사를 통한 투입계수와 비교 해 보았다.

• 전기의세계
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• 제23권2호
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• pp.46-54
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• 1974

The purposes of this paper are to deal with the design of m-input, m-output linear systems by the state variable feedback, and to extend the design capability of the state variable feedback design. The design requirements are decoupling and the exact realigation of desired transfer functions. Some methods are proposed to insert series compensators in the fixed plant in the cases when series compensators are needed to meet the input-output transfer matrix specification. The method for adding series compensators to the input channels of the fixed plant is shown by examples to lead both to the loss of the ability to decouple the augmented plant by the state variable feedback, and to the loss of desired zeroes. A method which avoids these two hazards is developed in which series compensators are put on the output channels of the fixed plant: it is proved that the augmented plant is F-invariant. By treating each subsystem individually, the designer can apply some of the previous developed knowledge of the state variable design of single-input, single-output systems.

• 동력기계공학회지
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• 제6권3호
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• pp.49-56
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• 2002

This study suggests a trajectory tracking controller composed of an input output linearization compensator and a linear controller. The input output linearization compensator is derived from the nonlinear equations of a pneumatic control system and it algebraically transforms a nonlinear system dynamics into a linear one, so that input output characteristics of the control system is linearized regardless of the variation of the operating point and linear control techniques can be applied. The results of nonlinear simulations show that the proposed controller tracks the given trajectories more accurately than a state feedback controller does.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.687-692
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• 1991

To reduce the complexity in constructing a fuzzy logic controller of multivariable systems, three major methods are presented. One is the method of constructing single-input-single-output fuzzy logic controllers after decoupling the target system. Another is the method of using fuzzy relation matrices which indicate the relation between each input and output. The other is the method of using the hierarchically classified inputs which dominantly influence one output than other inputs. Using the last two methods, simulation results of fuzzy logic controller implemented on 160MW boiler-turbine plant model are also shown.

• 전기학회논문지
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• 제62권3호
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• pp.355-364
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• 2013

Respect to the input AC voltage and output DC voltage, conventional three-phase PWM rectifier is classified as the voltage type rectifier with boost capability and the current type rectifier voltage with buck capability. Conventional PWM rectifier can not at the same time the boost and buck capability and its bridge is weak in the shoot- through state. These problems can be solved by Z-source PWM rectifier which has all characteristic of voltage and current type PWM rectifier. By shoot-through duty ratio control, the Z-source PWM rectifier can buck and boost at the same time, also, there is no need to consider the dead time. This paper proposes the input AC voltage sensorless control method of a three-phase Z-source PWM rectifier in order to accomplish the unity input power factor and output DC voltage control. The proposed method is estimated the input AC voltage by using input AC current and output DC voltage, hence, the sensor for the input AC voltage detection is no needed. comparison of the estimated and detected input AC voltage, estimated phase angle of the input voltage, the output DC voltage response for reference value, unity power factor, FFT(Fast Fourier Transform) of the estimated voltage and efficiency are verified by PSIM simulation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.395-400
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• 2004

In most physical processes, the transfer function includes time-delay, and in the general distributed control system using computer network, there exists inherent time-delay caused by the spatial separation between controllers and actuators. This work deals with the synthesis of a discrete-time controller for a nonlinear system and proposes a new effective method to compensate the influence of input time-delay. The controller is synthesized by using input/output linearization. Under the circumstance that input time-delay exists, the system response has more overshoot and tends to diverge. For these reasons, the controller has to produce future input value that will be needed for the system. In order to calculate the future input value, some predictors are adopted. Using the discretization via Euler's method, numerical simulations about the Van der Pol system are performed to evaluate the performance of the proposed method.