• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.238-243
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• 1986

Distillation columns are widely used in almost every chemical plant. The use of multivariable control for such units is attractive because of the strong interactions exhibited between outputs and inputs and the desire to control simultaneously both top and bottom products. In this research design of a robust multivariable controller for distillation column was considered; output feedback controller with proportional and integral modes was designed using pole assignment. The transfer function matrix was obtained by fitting the step response realtions between single input double output pairs of variables. This matrix was then converted to linear time invariant state space model by multivariable realization technique. With the proposed multivariable proportional and integral controller applied to the process, the result of the digital computer simulation showed a good performance of asymtotic tracking. The limited experimental performance of this multivariable control was compared with the result from simulation. It was found that the proposed controller performed satisfactorily for the distillation column which separated binary mixture of methanol and water.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.620-622
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• 2000

Linear pulse motor have many advantages. (simple control circuit, high stiffness characteristics, etc.) So, it may replace the solenoid as the valve driving device without difficulty and give full play to control the valve accurately. In this paper, we will analyze the LPM for designed proportional control valve and will conform the complex magnetic circuits to be composed LF and TF path.

• 한국군사과학기술학회지
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• 제10권2호
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• pp.53-60
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• 2007

This paper presents a robust nonlinear autopilot design method based on dynamic inversion and PI(Proportional-Integral) control law. The new controller structure which is different from previous work is composed of classical linear PI control law and nonlinear fast dynamic inversion. A pitch axis model of highly maneuverable missiles and a linearized model for designing Pl controller are presented. The performance of proposed method is illustrated via nonlinear simulations including aerodynamic uncertainties and actuator dynamics.

• 한국정밀공학회지
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• 제11권5호
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• pp.25-32
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• 1994

A nonlinear control algorithm for the depth control of underwater vehicles is presented. In order to consider the deadzone effect of the flow control valve, a nonlinear fuzzy logic controller (FLC) is synthesized and combined with a linear proportional-derivative-acceleration (PDA) controller, which is called the PDA/FLC controller. And to show the effectiveness of the PDA/FLC control system, it is compared with the linear PDA control system through computer simulation. It is found that the PDA/FLC control system is suitable one to maintain the desirable depth of underwater vehicles with deadzone.

• Earthquakes and Structures
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• 제18권5호
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• pp.609-623
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• 2020

This paper presents a displacement-based seismic design procedure for new structures with fluid viscous dampers and/or for existing structures, where these devices are required as a retrofit measure and damage control. To consider the non-proportional damping produced by these devices in a conventional modal spectral analysis, the effect of the fluid viscous dampers is approximated as the sum of a proportional damping matrix and a complementary matrix which is representative of non-proportional damping matrix. To illustrate the application of this procedure and evaluate the performance of structures designed with the procedure proposed, five regular plane frames: 8, 12, 17, 20 and 25-storey, and an 8-storey building are designed. The seismic demands used for design and validation were the records obtained at the SCT site during the 1985 Michoacan earthquake, and that of the 2017 Morelos - Puebla earthquake obtained at the Culhuacan site, both stations located on soft soil sites. To validate the procedure proposed, the performances and damage distributions used as design targets were compared with the corresponding results from the nonlinear step-by-step analyses of the designed structures subjected to the same seismic demands.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.109-114
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• 2002

The purpose of this study is to propose the general method for evaluating the equivalent damping ratios of a structure with supplemental response control dampers. We define Lyapunov function of which derivative can be expressed in autoregressive form and evaluate the equivalent damping ratios by using Lyapunov function and its derivative. This Lyapunov function may be called as generalized structural energy. In this study, it is assumed that the response of a structure is stationary random process and control dampers do not affect the modal shapes of a structure, and the structure has proportional damping. Proposed method can be used to get the equivalent damping ratios of a structure with non-linear control dampers such as friction dampers as well as linear control dampers. To show the effectiveness of the proposed method. we evaluate the equivalent damping ratios of a structure with viscous dampers. AMDs. and friction dampers. The equivalent damping ratios from proposed method are compared to those from eigenvalue analysis for linear control dampers. and those from time history analysis for non-linear control dampers. respectively.

• 전력전자학회논문지
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• 제19권6호
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• pp.538-548
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• 2014

This study provides a robust control of a grid-connected three-phase two-level photo voltaic inverter. The introduced control method uses the cascade control strategy to regulate AC-side current and DC-link voltage. A robust controller with integration action is used for the inner-loop AC-side current control, which maximizes the convergence rate using a linear matrix inequality-based optimization design method and eliminates the offset error. The robust controller design method considers the parameter uncertainty set to accommodate parameter mismatch and un-modeled components in the inverter model. An outer-loop proportional-integral controller is used to regulate DC-link voltage with linearization of DC/AC relation. The proposed control strategy is applied to a grid-connected 100 kW photo voltaic inverter.

• 드라이브 ㆍ 컨트롤
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• 제14권4호
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• pp.61-70
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• 2017

In this study, an extended-state-observer (ESO) based non-linear servo control is introduced for an electro-hydrostatic actuator (EHA). Almost hydraulic systems not only are highly non-linear system that has mismatched uncertainties and external disturbances, but also can not measure some states. ESO that only use an output signal can be used to compensate these uncertainties and estimate unmeasurable states. To improve the position tracking performance, the barrier Lyapunov function (BLF) that can guarantee an output tolerance is introduced for the position tracking error signal of back stepping control procedures. Finally, the proposed servo control is compared with the proportional-integral (PI) control.

• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.460-466
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• 2008

This paper deals with the stability analysis of a missile guidance loop employing an integrated proportional navigation guidance law. The missile guidance loop is formulated as a closed-loop control system consisting of a linear time-invariant feed-forward block and a time-varying feedback gain. Based on the circle criterion, we have defined the concept of absolute stability margins and obtained the gain and phase margins for the system assuming 1 st order missile/autopilot dynamics. The correlation between the absolute stability margins and the margins derived from the frozen system analysis is also discussed.

• 제어로봇시스템학회논문지
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• 제7권7호
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• pp.622-631
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• 2001

This paper presents a fuzzy modified PID controller that uses linear fuzzy inference method. In this structure, the proportional and derivative gains vary with the output of the system under control. 2-input PD type fuzzy controller is designed to obtain the varying gains. The proposed fuzzy PID structure maintains the same performance as the same performance as the general-purpose linear PID controller, and enhances the tracking performance over a wide range of input. Numerical simulations and experimental results show the effectiveness of the fuzzy PID controller in comparison with the conventional PID controller.