• 대한전기학회논문지:시스템및제어부문D
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• 제53권6호
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• pp.433-439
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• 2004

The Helicopter Simulator System is non-linear and complex. Futhermore, because of absence of its accurate mathematical model, it is difficult to control accurately its attitudes such as elevation angle and azimuth one. Therefore, we proposed a Hybrid GA-PID WAVENET(Genetic Algorithm Proportional Integral Derivative Wavelet Neural Network)control technique to control efficiently these angles. The proposed Hybrid GA-PID WAVENET is made through the following process. First, the WAVENET fundamental functions are defined. And their dilation and translation values are adjusted by GA to construct the optimal WAVENET controller. Secondly, the proportional, integral, and derivative gain coefficients of PR controller are tuned optimally. Finally, WAVENET controller which has a good transient characteristic and GA-PE controller which has a good steady state characteristic is adequately combined in hybrid type. Through the computer simulations, it is proved that the Hybrid GA-PE WAVENET control technique has a more excellent dynamic response than PID control technique and GA-PID one.

• 제어로봇시스템학회논문지
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• 제13권3호
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• pp.273-278
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• 2007

In this paper, a performance comparison between CLOS(Command to Line-of-Sight) guidance law and PN(Proportional Navigation) guidance law is made, based on a short range surface-to-air missile simulation program called KNUCLOS. This simulation program has a full nonlinear aerodynamic missile model, a tracker model for missile and target, and target model. According to the simulation results, the PN guidance law has a better performance than CLOS guidance law under various target speed.

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.877-885
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• 2018

Various controllers such as proportional-integral-derivative (PID) controllers have been designed and optimized for load-following issues in nuclear reactors. To achieve high performance, gain tuning is of great importance in PID controllers. In this work, gains of a PID controller are optimized for power-level control of a typical pressurized water reactor using particle swarm optimization (PSO) algorithm. The point kinetic is used as a reactor power model. In PSO, the objective (cost) function defined by decision variables including overshoot, settling time, and stabilization time (stability condition) must be minimized (optimized). Stability condition is guaranteed by Lyapunov synthesis. The simulation results demonstrated good stability and high performance of the closed-loop PSO-PID controller to response power demand.

• 한국정밀공학회지
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• 제15권12호
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• pp.142-147
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• 1998

Developing robot hands with multi-degree-of-freedom is one of the topics that researchers have recently begun to improve the limitation by adding flexibility and dexterity. In this study, an articulated servo-pneumatic robot hand system with direct-drive joints has been developed whose main feature is the minimization of the dimension. The servo-pneumatic system is advantageous to fabricate a dexterous robot hand system due to the high torque-to-weight and torque-to-volume ratio. This enables the design of a finger joint with an integrated rotary vane type actuator which produces high output torque without reduction gears, being very robust. In order to control the servo-pneumatic finger joints, a miniature proportional valve that can be attached to the robot hand is required. In this paper, a flapper nozzle type 4/3-way proportional directional valve has been designed and tested. The experimental results show that the developed valve can control a finger joint satisfactorily without much vibratory joint movements and acoustic noises.

• 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.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.16-21
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• 2008

In order to protect the environment from the refrigerant pollution, the $CO_2$ may be regarded as one of the most attractive alternative refrigerants for an automotive air-conditioning system. Control methods for a $CO_2$ system should be different because of $CO_2$'s unique properties as a refrigerant. Especially, the high-side pressure of a $CO_2$ system should be controlled for the effective operation of the system. High-side pressure algorithms, which were composed of the pressure setpoint algorithm and the pressure setpoint reset algorithm, were developed. Pressure setpoint algorithms, by using a neural network and by using a least square method, were developed and compared. Pressure setpoint reset algorithms, by using a fuzzy logic and by using a proportional logic, were also developed and compared. Simulation results showed that a least square method was more useful than a neural network for the pressure setpoint algorithm. And a proportional logic was more practical than a fuzzy logic for the pressure setpoint reset algorithm.

• 드라이브 ㆍ 컨트롤
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• 제9권4호
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• pp.32-41
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• 2012

Most diagnosis methods for servo valves requires installing spool displacement sensor or flow sensor as well as pressure sensor. The measurement of flow is hard to implement and many kinds of servovalves or proportional direction valves do not have a built-in spool displacement sensor. In this study, static performances of servovalve or proportional-direction-valve are studied theoretically and a diagnosis technique, which uses only load pressure and input current signal, is assessed. An experimental setup was made based upon a personal computer and the LabVIEW graphical language. A series of diagnosis tests were performed and the analysis results showed it possible to measure the pressure gain, hysteresis and null bias in a relatively simple methodology.

• IEIE Transactions on Smart Processing and Computing
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• 제5권1호
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• pp.35-42
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• 2016

Developments in power electronics have enabled the widespread application of Pulse Width Modulation (PWM) inverters, notably for connecting renewable systems to the grid. This study demonstrates that a high-quality power can be achieved using a stand-alone inverter, whereby the comparison between the power quality of the stand-alone inverter with battery storage (off-grid) and the power quality of the utility network is presented. Multi-loop control techniques for a single phase stand-alone inverter are used. A capacitor current control is used to give active damping and enhance the transient and steady state inverter performance. A capacitor current control is cheaper than the inductor current control, where a small current sensing resistor is used. The output voltage control is used to improve the system performance and also control the output voltage. The inner control loop uses a proportional gain current controller and the outer loop is implemented using internal model control proportional-integral-derivative to ensure stability. The optimal controls are achieved by using the Sisotool tool in MATLAB/Simulink. The outcome of the control scheme of the numerical model of the stand-alone inverter has a smooth and good dynamic performance, but also a strong robustness to load variations. The numerical model of the stand-alone inverter and its power quality are presented, and the power quality is shown to meet the IEEE 519-2014. Furthermore, the power quality of the off-grid system is measured experimentally and compared with the grid power, showing power quality of off-grid system to be better than that of the utility network.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.249-251
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• 2006

In this study, a systematic and effective tuning method of the actuator control parameters of the control loading system for aircraft based on control theory is presented. Firstly, to raise the time response of the system, the proportional gain and the integral gain of the velocity control loop is maximized within the range where vibration and noise does not occur. And then the position control loop is composed by getting the transfer function of the control loading system including the velocity control loop. With the root locus of the composed position control loop, the proportional gain of the position control loop that keeps stable transient state and leads good time response of the system is predicted, and the simulations are performed by using the predicted gain. Lastly, the actuator control parameters of actual control loading system are set to the previously obtained gain values. And the experiments to actuate the control loading system are executed. It shows that the tuning method of the actuator control parameter proposed in this study is applied to actual control loading system very well by comparing the results of the experiments with those of the simulations.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1862-1866
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• 2003

A control system design with Coefficient Diagram Method (CDM) is proven that effective for SISO control design. But the control system design for MIMO via CDM is not concrete procedure. In this paper presents the control system design method for quadruple-tank process via CDM. By using the decentralized method for both non-minimum phase and minimum phase are made. The results from Integral-Proportional (I-P) controller’s design via CDM and standard Proportional-Integral (PI) controls are also shown to compare the merits of the proposed controllers.