• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.582-587
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• 1987

In this paper, a controller design method for the DC motor driving system is described emphasizing the specified degree of accuracy undergoing large time varying disturbances, coulomb friction and arm-load resonance. A feedforward compensation technique using the current controller is proposed, and resulting in the performance improvement as well as the implementational simplicity. A time-weighted quadratic performance index is used in the optimization of the controller, which is a salient way of obtaining better closed-loop performance in a simple manner. Computer simulations are also given to show the usefulness of the proposed techniques.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.407-409
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• 1998

In order to improve the tracking performance of $2{\times}2$ multivariable control systems, a fuzzy control algorithm with feedforward compensator is represented. The method consists in two steps. First, neglecting interconnections. one designs a fuzzy controller to each individual loop. In the second stage, low-order transfer functions of outputs to reference inputs are estimated. We propose a design method of the feed forward compensator based on the transfer functions. An illustrative example are shown.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.81-85
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• 2010

This paper deals with the issue of motion control of a single rod cylinder-load system using simple adaptive control (SAC) method. Prior to controller design, the experiment of open-loop response has been performed. Based on it, design parameters of transfer function are obtained. The effect of parallel feedforward compensator has been investigated by computer simulation, suppressing the oscillatory motion. Through experiments it is conformed that the SAC method gives good tracking performance compared to the PD control method.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.6
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• pp.576-581
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• 1997

DC-DC converter with chopper is seen to have problems, such as, loop instability and degradation of transient response, due to the interaction between input filter and switching regulator. In this paper, the switching regulator consisting of input filter and double chopper is analyzed, and the state space model at continuous current mode and the transfer function between duty ratio of switching pulse and output voltage are derived. The controller in this paper is designed as feedforward(P) and feedback(PI) control scheme to minimize the variation of output voltage, and computer simulation results are presented to show the performance of the proposed controller.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.44 no.4
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• pp.447-452
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• 1995

In this paper a simple method of a position control for brushless DC motor is presented. For precise position control, a high performance torque controller is needed and a novel current control method is proposed. The current controller detects the uncommutating mode current for every 60.deg. (elec. angle) and controls it with PI controller. The current control loop includes the feedforward of back EMF and the feedforward of the neutral voltage between the neutral point of the inverter and the neutral point of the machine. In the position control, the acceleration pattern is calculated from the position reference. Then the speed trajectory is calculated from the acceleration pattern. The experimental results are presented to verify the proposed methods.

• Journal of Advanced Navigation Technology
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• v.8 no.2
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• pp.184-190
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• 2004

A feedforward linear power amplifier (FLPA) has been developed for UHF-band RFID reader applications. The main and error amplifiers are composed of a 2 stage so that linearity of the FLPA can be improved. The FLPA has been implemented on an FR-4 substrate (Er=4.7 and thickness=0.8 mm) with 3-dB and 10-dB hybrid couplers for input/output power divider and combiner. For 2-tone measurement (input level=-11 dBm at $f_1$=915 MHz and $f_2$=916 MHz), the FLPA exhibits a -18.52 dBm of $IMD_3$, which indicates that $IMD_3$ cancellation with feedforward loop is more than 27 dB. From 890 to 960 MHz, 1-dB gain compression output power and power gain of the FLPA are higher than 30 dBm and 40 dB, respectively.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.1
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• pp.58-64
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• 2016

This study presents a design method for a single-loop voltage controller that is suitable for an arbitrary waveform generator (AWG). The voltage control algorithm of AWG should ensure high dynamic performance and should attain sufficient robustness to disturbances such as inverter nonlinearity, sensor noise, and load current. By analyzing the power circuit of AWG, control limitation and control target are presented to improve the dynamic performance of AWG. The proposed voltage control algorithm is composed of a single-loop output voltage control, an inverter current feedback term to improve transient response, and a load current feedforward term to prevent voltage distortion. The guideline for setting control gain is presented based on output filter parameters and digital time delay. The performance of the proposed algorithm is proven by experimental results through comparison with the conventional algorithm.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.5
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• pp.152-158
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• 1996

A novel resonant pulse control technique which generates high-quality sinusoidal output voltage from a resonant dc link inverter is presented for UPS applicatons. The proposed control technique limits resonant voltae overshoot without any passive or active clamp circuit, resulting in resonant pulses iwth uniform amplitude and high efficiency. The output voltage is controlled by the third order contorller iwth an inner loop of th efilter inductor current and the feedforward controller. Analysis and design of the proposed control technique are illustrated and verified on a 5kVA experimental unit.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.1140-1145
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• 1989

A general dynamic iterative learning control scheme is proposed for a class of nonlinear systems. Relying on stabilizing high-gain feedback loop, it is possible to show the existence of Cauchy sequence of feedforward control input error with iteration numbers, which results in a uniform convergance of system state trajectory to the desired one.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.236-241
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• 1988

This note considers the class of controllers with integral action which arise directly from appropriate system models. Via internal model principle approach, a corresponding class of self-tuning controller is shown to have both integral action in controller and offset removal in the tuning algorithm. The key idea is to constrain the estimator in each step in order to ensure that dc gain of feedforward and feedback polynomial of adaptive controller are always equal, thus allowing the loop integrator to work properly.