• Journal of the Korean Institute of Telematics and Electronics
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• v.7 no.2
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• pp.26-32
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• 1970

Among the various methods used for determining control system dynamics, the method using cross-correlation function seems useful if the white noise can be available as a test signal. In this paper, results are reported of a M-sequence generator which was built by means of IC shift register as it designed by the authors. This signal appears very useful and promises future applications in adaptive control systems.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.26-35
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• 2004

As part of thrust control technology research on turbopump-fed type liquid-propellant rocket engine system, the low frequency dynamic characteristics of turbopump was investigated. It can be described that a turbopump system has a 1st-order lag element. When the value, which was resulted by subtraction of the variation of turbine moment with respect to the variation of revolution number from the variation of pump moment with respect to the variation of revolution number, was positive, the time constant of the 1st-order lag element was positive which stood for a stable system. Increasing the above-mentioned valve within positive range leaded to the increase of response and to the decrease of controllability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.7
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• pp.618-626
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• 2011

In order to complete missions in a complicated terrain or highly dangerous area, an unmanned aerial vehicle(UAV) needs a fine controller to precisely follow the desired path. A PID controller used for the path following feeds forward path curvature information to the control input to improve the path following performance. High gain for PID controller is necessary to follow path tightly. However the high gain could cause instability or performance degradation when the vehicle has slow dynamics. We present PID controller design method which considers response delay of vehicle as well as path curvature. In order to obtain path curvature the desired path is described as a 3rd order polynomial by applying cubic spline interpolation. We apply the proposed controller to the path following of a UAV which is operated in high altitude and has very slow lateral dynamics. The lateral dynamics are modelled as a first order delayed system in the controller design. Nonlinear simulation shows the UAV with proposed controller follows an arbitrary path very tightly.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.5
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• pp.349-359
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• 2022

The aim of this study is to analyze the dynamic characteristics of proportional control valves according to various working conditions as a basic study for developing proportional control valves for auto-steering tractors. The dynamic characteristics of proportional valves were measured using hydraulic characteristics measurement system, and the power was analyzed using measured flow rate and pressure data. As the experimental conditions, the tractor engine speed and steering angle was selected as the main variables, and the experiment was performed on urethane road conditions. As a result, it was found that the flow rate, pressure, and power of the proportional control valve increased as the tractor engine speed and steering angle increased. In particular, as the steering angle increased at the same engine speed, the flow rate, pressure, and power tended to increase by up to 190%, 172%, and 273%, respectively. Similarly, as the engine speed increased at the same steering angle, the flow rate, pressure, and power tended to increase up to 161%, 122%, and 168%, respectively. Therefore, it can be seen that the steering angle has a higher influence on the dynamic characteristics of the proportional control valve than the engine speed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.333-338
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• 2002

자기베어링의 회전정밀도에 영향을 미치는 인자로 PWM 전력증폭기, 위치 센서 등과 같은 자기베어링 구성 장치의 동특성 및 정밀도, 시스템의 정확한 모델링, 제어기법, 런아웃 등이 있다. 본 연구에서는 능동 자기베어링을 제어하기 위해 자기베어링의 PWM 전력증폭기와 회전축을 모델링하고 이를 바탕으로 능동 자기베어링 제어를 위한 PID 제어기를 구성하였으며, 변위 센서의 부착위치 및 회전축의 진원도의 영향으로 발생하는 주기적인 런아웃 요소를 첨가하여 런아웃의 영향을 확인하였으며, 런아웃 (Runout)에 의해 발생하는 에러(Error)를 효과적으로 제어하여 자기베어링의 제어 정밀도를 향상시키기 위한 방법으로 기본적인 PID 제어기에 최소평균자승(Least Mean Square, LMS) 알고리즘을 적용한 적응 피드포워드 제어기를 구성하여 자기베어링의 능동 제어에서 발생하는 주기적인 런아웃을 효과적으로 제어할 수 있음을 MATLAB을 통한 시뮬레이션을 통해 확인하였다.

• Resources Recycling
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• v.10 no.6
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• pp.15-21
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• 2001

Shape-controlled copper oxides have been recovered from copper-containing waste etchant by neutralization with alkalihydroxide. Large amount of copper-containing waste etchant is generated from Printed Circuit Board industry. In an environmental and economic point of view, retrieve of the valuable natural resource from the waste is important. In recycling process of copper oxide from the waste etchant, reaction temperature controls shapes and sizes of the products. Copper oxide recovered below reaction temperature $40^{\circ}C$ was of a needle shape, while copper oxide comes in a platy shape above $40 ^{\circ}C$ . Physical properties of samples have been characterized using SEM, XRD, TGA and Atomic absorption spectroscopy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.5
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• pp.97-103
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• 2004

Nowadays, many kinds of research for airship are studying with increasing of interests of airship. But these are far from perfect. The data acquisition from the actual flight test has lots of difficulties because of the characteristics from the slow dynamic response and high sensitivity for external environment. In this paper, through the actual flight test, appropriateness of the mathematical dynamic model applied here was verified by comparing the test data with simulation data in same control conditions.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.3
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• pp.205-212
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• 2007

This paper presents a direct instantaneous torque control (DITC) of Switched Reluctance Motor (SRM) with a novel 4-level converter to develop a uniform torque and to improve a dynamic performance. The DITC method can reduce a high torque ripple of SRM. Drive efficiency and dynamic performance with conventional drive are low due to a slow excitation current build-up. Since the 4-level converter can obtain an addition boosted voltage to have a fast excitation and demagnetization, it can Improve dynamic performance and efficiency easily. To apply the DITC technique to a 4-level converter, a novel control scheme is presented according to the operating modes. Additionally, selection of capacitances of boosted capacitor and efficiency improvement of 4-level converter are analyzed. At last, the validity of proposed method is verified by some computer simulations md comparative experiments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.529-532
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• 2012

This paper presents the system modeling, analysis, and controller design and implementation with a inverted pendulum system in order to test robust algorithm for sweeping machine. The balancing of an inverted pendulum by moving pendulum robot like as 'segway' along a horizontal track is a classic problem in the area of control. This paper will describe two methods to swing a pendulum attached to a cart from an initial downwards position to an upright position and maintain that state. The results of real experiment show that the proposed control system has superior performance for following a reference command at certain initial conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3821-3826
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• 2014

This paper proposes a methodology for developing the performance of a solenoid valve for vehicles based on the dynamic analysis model by an electromagnetic field. The high performance solenoid model with a low current and high thrust was induced through the shape optimal design of the yoke and plunger. To perform the dynamic analysis of the solenoid valve, the input current profile was analyzed. The speed and thrust information was analyzed by FEM with this current profile. The co-simulation method of the circuit model of control logic and electromagnetic model of the solenoid valve was also proposed to analyze the performance with several current patterns. Finally, the performance of the original model and optimal one was compared.