• Journal of Power Electronics
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• v.11 no.1
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• pp.59-63
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• 2011

This paper presents the modeling of the sampling effect in the p-type average current mode control. The prediction of the high frequency components near half of the switching frequency in the current loop gain is given for the p-type average current mode control. By the proposed model, the prediction accuracy is improved when compared to that of conventional models. The proposed method is applied to a buck converter, and then the measurement results are analyzed.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.916-924
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• 2008

In this paper dynamic modeling parameters were estimated using a frequency domain estimation method. A systematic flight test method was employed using preprogrammed multistep excitation of the swashplate control input. In addition when one axis is excited, the autopilot is engaged in the other axis, thereby obtaining high-quality flight data. A dynamic model was derived for a small scale unmanned helicopter (CNUHELI-020, developed by Chungnam National University) equipped with a Bell-Hiller stabilizer bar. Six degree of freedom equations of motion were derived using the total forces and moments acting on the small scale helicopter. The dynamics of the main rotor is simplified by the first order tip-path plane, and the aerodynamic effects of fuselage, tail rotor, engine, and horizontal/vertical stabilizer were considered. Trim analysis and linearized model were used as a basic model for the parameter estimation. Doublet and multistep inputs are used to excite dynamic motions of the helicopter. The system and input matrices were estimated in the frequency domain using the equation error method in order to match the data of flight test with those of the dynamic modeling. The dynamic modeling and the flight test show similar time responses, which validates the consequence of analytic modeling and the procedures of parameter estimation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.425-430
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• 2002

An automatic transmission model using the bond graph techniques is developed for analyzing shift characteristics of vehicles. Bond graph models can be systemically manipulated to yield state space equations of standard form. Bond graph techniques are applied for modeling overall automatic transmission systems and shift models. A fuzzy controller is synthesized for the verification of a shifting model in the ${1^st} gear to the {2^nd}$ gear. Simulation results show the fitness of models by the bond graph techniques.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.243-246
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• 1994

In this paper, a self-learning fuzzy controller is designed with a fuzzy approximation of an inverse model. The aim of an identification is to find an input command which is control of a system output. It is intuitional and easy to use a classical adaptive inverse modeling method for the identification, but it is difficult and complex to implement it. This problem can be solved with a fuzzy approximation of an inverse modeling. The fuzzy logic effectively represents the complex phenomena of the real world. Also fuzzy system could be represented by the neural network that is useful for a learning structure. The rule of a fuzzy inverse model is modified by the gradient descent method. The goal is to be obtained that makes the design of fuzzy controller less complex, and then this self-learning fuzz controller can be used for nonlinear dynamic system. We have applied this scheme to a nonlinear Ball and Beam system.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.83-89
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• 2000

This paper presents a dynamic modeling and a sliding mode controller for the high-speed / high-accuracy position control system. Selected target system is the wire bonder head assembly which is used in semiconductor assembly process. This system is a reciprocating one around the pivot point that consists of VCM(voice coil motor) as a actuator and transducer horn as a bonding tool. For the modeling elements, the system is divided into electrical circuit, magnetic circuit and mechanical system. Each system is modeled by using the bond graph method and united into the full system. Two major aims are considered in the design of the controller. The first one is that the horn must track the given reference trajectory. The second one is that the controller must be realizable by using the DSP board. Computer simulation and experimental results show that the designed sliding mode controller provides better performance than the PID controller.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1463-1471
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• 2009

In this paper, a new algorithm of Integrated Volt/Var Control (IVVC) is proposed using Volt/Var control for the Distribution Automation System (DAS) based on the modeling of the distributed load and the distributed current. In the proposed, the load flow based on the modeling of the distributed load and the distributed current are estimated from constants of four terminals using the measurement of the current and power factor from a Feeder Remote Terminal Unit (FRTU). For Integrated Volt/Var Control (IVVC), the gradient method is applied to find optimal solution for tap and capacity control of OLTC (On-Load Tap Changers), SVR (Step Voltage Regulator), and SC (Shunt Condenser). What is more Volt/Var control method is proposed using moving the tie switch as well as IVVC algorithm using power utility control. In the case studies, the estimation and simulation network have been testified in Matlab Simulink.

• Journal of Power Electronics
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• v.10 no.1
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• pp.97-105
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• 2010

This paper presents the modeling, control and simulation of an interconnection system (ICS) of cascaded distributed generation (DG) modules for both grid-tied and stand-alone operations. The overall configuration of the interconnection system is given. The interconnection system consists of a cascaded DC/DC boost converters and a DC/AC inverter. Detailed modeling of the interconnection system incorporating a cascaded architecture has not been considered in previous research. In this paper, suitable control systems for the cascaded architecture of power electronic converters in an interconnection system have been studied and modeled in detail. A novel control system for DC/DC boost converters is presented based on a droop voltage controller. Also, a novel control strategy for DC/AC inverters based on the average large signal model to control the aggregated DG modules under both grid-tied and stand-alone modes is demonstrated. Simulation results indicate the effectiveness of the proposed control systems.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.12
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• pp.81-90
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• 1995

Anti-lock Brake System has been developed to reduce tendency for wheel lock and improve vehicle control during sudden braking on slippery road surfaces. This is achieved by controlling the braking pressure avoiding wheel lock, while retaining handling and brake performance. This paper is concerned about characteristics of a solenoid valve in hydraulic modulator for controlling brake pressure. First, it was modeling the electromagnet by the permeance method. Second, it was modeling the commercial Maxwell poackage program. And then, a experiment was performed in order to justify modeling. The result of modeling coincided with teh result of experiment and commercial packabe program. As a result, these modelings will be able to use in analysis of dynamic character- istics of the solenoid valve for braking.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1935-1944
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• 2018

With the increase of the production of energy from renewable, it becomes important to look at techniques to store this energy. Therefore, a single winding bearingless flywheel motor (SWBFM) specially for flywheel energy storage system is introduced. For the control system of SWBFM, coupling between the torque and the suspension subsystems exists inevitably. It is necessary to build a reasonable radial force mathematical model to precisely control SWBFM. However, SWBFM has twelve independently controlled windings which leads to high-order matrix transformation and complex differential calculation in the process of mathematical modeling based on virtual displacement method. In this frame, a Maxwell tensor modeling method which is no need the detailed derivation and complex theoretical computation is present. Moreover, it possesses advantages of universality, accuracy, and directness. The fringing magnetic path is improved from straight and circular lines to elliptical line and the rationality of elliptical line is verified by virtual displacement theory according to electromagnetic torque characteristics. A correction function is taken to increase the model accuracy based on finite element analysis. Simulation and experimental results show that the control system of SWBFM with radial force mathematical model based on Maxwell tensor method is feasible and has high precision.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.2
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• pp.1-6
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• 2007

During the last few decades, excavation automation has been investigated to protect the operator from the hazardous working environment and to relieve the cost of the skilled operator. Therefore, a number of modelling and controller design methods of the hydraulic excavator are proposed in many literatures to realize the excavation automation. In this article, a geometric approach far the multi-body system modeling is adopted to develop the excavator mechanism model that contains 4 kinematic loops and 12 links. Considering a simple soil mechanism model with a number of uncertain soil parameters, an adaptive trajectory tracking control strategy based on the developed excavator model is proposed. The improved performance of the designed controller over the simple PID controller is validated via the simulation study.