• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.1
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• pp.10-15
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• 2004

We present a state-space approach to make non-square linear systems strictly passive by using an input-dimensional parallel feedforward compensator. A necessary and sufficient condition for the existence of the parallel feedforward compensator is given by the static output feedback formulation, which enables to utilize linear matrix inequality. By modifying the structure of the compensator the additional technical assumption in the previous result [1] is removed. The effectiveness of the proposed method is illustrated by some numerical examples which can be stabilized by the proportional-derivative (PD) and proportional-derivative-integral (PID) control laws. The proposed control scheme can successfully replace the measurements of derivative terms in the control laws.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.82-92
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• 1999

In this paper, we realize the active PFC(Power Factor Correction) system of the BF(Boost Forward) converter with the PWM-PFM control technique to control DC output voltage, to rermve the noise like hanronics at the output voltage, amd to control the input ClUTent with sinusoidal wave synchronized by the source voltage. We take the simulation and analyze the switching signal of the BF converter, input/output voltage and current, its harmonics and power factor through PSpice. And it has bren obtained harmonic reduction and efficiency improverrent.errent.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1196-1198
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• 1996

It is well known that the controller output limits have a significant effect on the closed loop system performance. GPC has many tuning-knobs which can he used to minimize actuator activity. Especially, increasing the control weighting $\lambda$ cuts down the controller output variance. Using this property, we propose the GPC with Input constraints(GPCIC) which is based on the relation between control weighting $\lambda$ and optimal solution of the unconstrained GPC. The GPCIC algorithm is the calculation of the optimal $\lambda$ such that the output of the unconstrained GPC is satisfied with the rate Ind the level constraint.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.571-575
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• 1986

The squirrel-cage induction motor can be characterized as a nonlinear and multi-input, multi-output system, and has the unmeasurable states which are the rotor currents. In this paper, the time-delayed output feedback method is applied to the speed control of induction motor driven by the current-controlled PWM inverter and its performance is investigated by using the computer simulation.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.2
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• pp.104-109
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• 2000

In this paper, the output feedback stabilizing problem is solved using any given state feedback control law. Compared to the linear systems is not so straightforward for nonlinear systems. We briefly explain the intrinsic obstructions for this problem and provide new output feedback scheme which achieves the semi-global stabilization with the high-gain state observer. THe overall uniform observability of the plant. Therefore, the result can be regarded as an extension of the separation principle for linear systems in some aspect.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1045-1052
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• 2000

In this paper, we propose a method to apply the Input Shaping Technique (IST) to multi-input multi-output (MIMO) systems. In MIMO systems, there is a high possibility of multi-mode residual vibration. The IST filter designed for this multi mode may need a longer time to suppress the residual vibration. Previous works prove that we can shorten the time lag by using negative sequence. This negative sequence, however, causes another problem - it requires excessive control input. In this paper, we provide a remedy to reduce the size of control input by limiting the reference input by limiting the reference input and its derivative. The result of simulations and experiments on a 2 link flexible arm confirmed the effectiveness of the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1711-1716
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• 2004

This paper presents identification and control of a 10-m antenna via accelerometers and angle encoder data. Artificial Neural Networks can be used effectively for the identification and control of nonlinear dynamical system such as a large flexible antenna. Some identification results are shown and compared with the results of conventional prediction error method. And we use a neural network inverse model for control the large flexible antenna. In the neural network inverse model, a neural network is trained, using supervised learning, to develop an inverse model of the antenna. The network input is the process output, and the network output is the corresponding process input. The control results show the validation of the ANN approach for identification and control of the 10-m flexible antenna.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.10
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• pp.165-171
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• 1998

An axial electromagnetic levitation system using attractive force is a highly nonlinear system due to the nonlinearity of materials, variable air gap and flux density. To control the levitating system with large air gap, a conventional PID control based on the linear model is not satisfactory to obtain the desired performance and the position tracking control of the sinusoidal motion by simulation results. Thus, sliding mode control(SMC) based on the input-output linearization is suggested and evaluated by simulation and experimental approaches. Usefulness of the SMC to this system is conformed experimentally. If the expected variation of added mass can be included in the gain conditions and the model, the position control performance of the electromagnetic levitation system with large air gap will be improved with robustness.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.58-60
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• 2017

In the offshore crane system, the requirements on the operating safety are extremely high due to many external factors. This paper describes a model for studying the dynamic behavior of the offshore crane system. The obtained model allows to evaluate the fluctuations of the load arising from the elasticity of the rope. Especially, in this paper, the authors design control system in which just winch rotation angle and rope tension are used without load position information. The controller design based on input-output feedback linearization theory is presented which can handle the effect of the elasticity of the rope and track the load target trajectory input. Besides that, a full order observer is designed to estimate unknown states. Finally, By the experiment results, the effectiveness of proposed control method is evaluated and verified.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.619-621
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• 2005

This paper proposes apractical design method for ship-to-ship missiles' autopilot. When the pre-designed analogue autopilot is implemented in digital way, theygenerally suffer from severe performance degradation and instability problem even for a sufficiently small sampling time. Also, aerodynamic uncertainties can affect the overall stability and this happens more severely when the nonlinear autopilot is digitally implemented. In order to realize a practical autopilot, two main issues, digital implementation problem and compensation for the aerodynamic uncertainties, are considered in this paper. MIMO (multi-input multi-output) nonlinear autopilot is presented first and the input and output of the missile are discretized for implementation. In this step, the discretization effect is compensated by designing an additional control input. Finally, we design a parameter adaptation law to compensate the control performance. Stability analysis and 6-DOF (degree-of-freedom) simulations are presented to verify the proposed adaptive autopilot.