• Title/Summary/Keyword: Open loop response

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A study on the Parameter Regulation of PID Output Feedback Controllers (PID출력귀환 제어기의 변수조정에 관한 연구)

  • 성원기;최종수;하용수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.10 no.4
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    • pp.184-192
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    • 1985
  • The parameter regulation of proportional-plus-intergral-plus-derivative output feedback controllers is presented in the practical compter simulation and the time-domain analysis. Particularly, the restriction of parameter regulation for PID controller utilization is investigated as a result of simulation method. It is finally noted that one may resort to the design of controllers, as investigated, for rapid steady-state response, disturbance rejection, and transient response performance (over 3rd-order process) without computing the open-loop transfer functionmatrix. in consequence is presented the block diagram of sensor base system for PID output feedback controllers.

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Responses of Droplet Evaporation to High-Pressure Oscillations (강한 압력 교란에 구속된 고압 액적의 연소 응답)

  • Kim, Sung-Yup;Yoon, Woong-Sup
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1286-1291
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    • 2004
  • In order for studying pressure-coupled dynamic responses of droplet vaporization, open-loop experiment of an isolated droplet vaporization exposed to pressure perturbations in stagnant gaseous environment is numerically conducted. Governing equations are solved for flow parameters at gas and liquid phases separately and thermodynamic parameters at the interfacial boundary are matched for problem closure. For high-pressure effects, vapor-liquid interfacial thermodynamics is rigorously treated. A series of parametric calculations in terms of mean pressure level and wave frequencies are carried out employing a n-pentane droplet in stagnant gaseous nitrogen. Results show that wave instability in view of pressure-coupled vaporization response seems more susceptible at higher pressures and higher wave frequencies. Mass evaporation rate responding to pressure waves is amplified with increase in pressure due to substantial reduction in latent heat of vaporization. Augmentation of perturbation frequency also enhances amplification due to the reduction of phase differences between pressure perturbation and surface temperature fluctuation.

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Modified Direct Torque Control using Algorithm Control of Stator Flux Estimation and Space Vector Modulation Based on Fuzzy Logic Control for Achieving High Performance from Induction Motors

  • Rashag, Hassan Farhan;Koh, S.P.;Abdalla, Ahmed N.;Tan, Nadia M.L.;Chong, K.H.
    • Journal of Power Electronics
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    • v.13 no.3
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    • pp.369-380
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    • 2013
  • Direct torque control based on space vector modulation (SVM-DTC) protects the DTC transient merits. Furthermore, it creates better quality steady-state performance in a wide speed range. The modified method of DTC using SVM improves the electrical magnitudes of asynchronous machines, such as minimizing the stator current distortions, the stator flux with electromagnetic torque without ripple, the fast response of the rotor speed, and the constant switching frequency. In this paper, the proposed method is based on two new control strategies for direct torque control with space vector modulation. First, fuzzy logic control is used instead of the PI torque and a PI flux controller to minimizing the torque error and to achieve a constant switching frequency. The voltages in the direct and quadratic reference frame ($V_d$, $V_q$) are achieved by fuzzy logic control. In this scheme, the switching capability of the inverter is fully utilized, which improves the system performance. Second, the close loop of stator flux estimation based on the voltage model and a low pass filter is used to counteract the drawbacks in the open loop of the stator flux such as the problems saturation and dc drift. The response of this new control strategy is compared with DTC-SVM. The experimental and simulation results demonstrate that the proposed control topology outperforms the conventional DTC-SVM in terms of system robustness and eliminating the bad outcome of dc-offset.

A Pilot Study on the Muscle Activities in Step Input Test as an Indicator of the Vehicle Characteristics

  • Kong, Yong-Ku;Jung, Myung-Chul;Lee, In-Seok;Hyun, Young-Jin;Kim, Chang-Su;Seo, Min-Tae
    • Journal of the Ergonomics Society of Korea
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    • v.32 no.3
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    • pp.217-227
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    • 2013
  • Objective: The purpose of this study was to analyze 'response time', 'peak response time' and 'overshoot value' for each muscle by applying the EMG signal to the vehicle response in ISO 7401 and to quantify the response of the driver according to vehicle characteristics by comparing vehicle characteristics and muscle responses of the driver. Background: The Open-loop test defined in international standards ISO 7401 is the only method for evaluating the performance of the vehicle. However, this test was focused only on mechanical responses, not driver's ones. Method: One skilled male driver(22 yrs. experience) was participated in this experiment to measure muscle activities of the driver in transient state. Then the seven muscle signals were applied to calculate 'response time', 'peak response time', and 'overshoot value'. Results: In the analyses of the EMG data, the effects of vehicle type and muscle were statistically significant on the 'response time' and 'peak response time'. Also, the effects of vehicle type, muscle, and lateral acceleration level were statistically significant on the 'overshoot value' in this study. According to the analyses of the vehicle motion data, vehicle motion variable(LatAcc, Roll, YawVel) was statistically significant on the 'response time' and vehicle type, vehicle motion variable, and lateral acceleration level were statistically significant on the 'peak response time', respectively. Conclusion: In the analyses of the 'response time' and 'overshoot value', the data of muscle activities(EMGs) was better index that could evaluate the vehicle characteristic and performance than the data of vehicle motion. In case of peak response time, both EMG and vehicle motion data were good index. Application: The EMGs data from a driver might be applicable as index for evaluation of various vehicle performances based on this study.

Performance Evaluations of Four MAF-Based PLL Algorithms for Grid-Synchronization of Three-Phase Grid-Connected PWM Inverters and DGs

  • Han, Yang;Luo, Mingyu;Chen, Changqing;Jiang, Aiting;Zhao, Xin;Guerrero, Josep M.
    • Journal of Power Electronics
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    • v.16 no.5
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    • pp.1904-1917
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    • 2016
  • The moving average filter (MAF) is widely utilized to improve the disturbance rejection capability of phase-locked loops (PLLs). This is of vital significance for the grid-integration and stable operation of power electronic converters to electric power systems. However, the open-loop bandwidth is drastically reduced after incorporating a MAF into the PLL structure, which makes the dynamic response sluggish. To overcome this shortcoming, some new techniques have recently been proposed to improve the transient response of MAF-based PLLs. In this paper, a comprehensive performance comparison of advanced MAF-based PLL algorithms is presented. This comparison includes HPLL, MPLC-PLL, QT1-PLL, and DMAF-PLL. Various disturbances, such as grid voltage sag, voltage flicker, harmonics distortion, phase-angle and frequency jumps, DC offsets and noise, are considered to experimentally test the dynamic performances of these PLL algorithms. Finally, an improved positive sequence extraction method for a HPLL under the frequency jumps scenario is presented to compensate for the steady-state error caused by non-frequency adaptive DSC, and a satisfactory performance has been achieved.

Construction of Current Sensor Using Hall Sensor and Magnetic Core for the Electric and Hybrid Vehicle (홀소자와 자기코어를 이용한 하이브리드 및 전기자동차용 전류센서 제작)

  • Yeon, Kyoheum;Kim, Sidong;Son, Derac
    • Journal of the Korean Magnetics Society
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    • v.23 no.2
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    • pp.49-53
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    • 2013
  • A current sensor is one of important component which is used for the electrical current measurement during charge and discharge of the battery, and monitoring system of the motor controller in the electric and hybrid vehicle. In this study, we have developed an open loop type current sensor using GaAs Hall sensor and magnetic core has an air gap. The Hall sensor detect magnetic field produced by the current to be measured. The 3 mm air gap core was made by HGO electrical steel sheets after slitting, winding, annealing, molding, and cutting. Developed current sensor shows 0.03 % linearity within DC current range from -400 A to +400 A. Operating temperature range was extended to the range of $-40{\sim}105^{\circ}C$ using temperature compensating electronic circuit. To Improve frequency bandwidth limit due to the air flux of PCB (Printed Circuit Board) and Hall sensor, We employed an air flux compensating loop near Hall sensor or on PCB. Frequency bandwidth of the sensor was 100 kHz when we applied sine wave current of $40A{\cdot}turn$ in the frequency range from 100 Hz to 100 kHz. For the dynamic response time measurement, 5 kHz square wave current of $40A{\cdot}turn$ was applied to the sensor. Response time was calculated time reach to 90 % of saturation value and smaller than $2{\mu}s$.

Control of Focal Plane Compensation Device for Image Stabilization of Small Satellite Camera (소형 위성 카메라의 영상안정화를 위한 초점면부 보정장치의 제어)

  • Kang, Myoungsoo;Hwang, Jaihyuk;Bae, Jaesung
    • Journal of Aerospace System Engineering
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    • v.10 no.1
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    • pp.86-94
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    • 2016
  • In this paper, position control of focal plane compensation device using piezoelectric actuator is conducted. The forcal plane compensation device installed on earth observation satellite camera compensates micro-vibration from reaction wheels. In this study, four experimental models of the open-loop compensation device are derived using MATLAB system identification toolbox in the input range of 0~50Hz. Subsequently, the PID controller for each model is designed and the performance test of each controller is conducted through MATLAB/Simulink. According to frequency response analysis of the closed-loop compensation device system, the PID controller designed for 38~50Hz input range has enough tracking performance for the whole 0~50Hz input range. The maximum output error is about $1{\mu}m$ for the input range. The simulation results has been verified by the experimental method.

Controlling Factors of Open-Loop Combustion Response to Acoustic Pressures in Liquid Propellant Rocket Engine (강한 압력파동에 구속된 액체 추진제 연소응답의 지배인자)

  • Yoon Woongsup;Lee Gilyong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.10a
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    • pp.267-273
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    • 2004
  • This paper targets to define controlling factors of pressure-coupled combustion response and estimate their effects on droplet evaporation process. Dynamic characteristics of hydrocarbon propellant vaporization perturbed by acoustic pressure are numerically simulated and analyzed. 1-D droplet model including phase equilibrium between two phases is applied and acoustic wave is expressed by harmonic function. Effects of various design factors and acoustic pressure on combustion response are investigated with parametric studies. Results show that driving frequency of acoustic perturbation and ambient pressure have important roles in determining magnitude and phase of combustion response. On the other hand, other parameters such as gas temperature, initial droplet size and temperature, and amplitude of acoustic wave cause only minor changes to magnitude of combustion response. Resultant changes in phase of heat of vaporization and thermal wave in droplet highly influence magnitude and phase of combustion response.

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Simple Adaptive Position Control of a Hydraulic Cylinder-load System Driven by a Proportional Directional Control Valve (비례 방향제어 밸브에 의하여 구동되는 유압실린더-부하계의 단순 적응 위치제어)

  • Cho, Seung-Ho;Lee, Min-Woo
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.8
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    • pp.936-941
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    • 2011
  • 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 and used for controller design. 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.

Active Vibration Control of Slewing Smart Beam (회전지능보의 능동진동제어)

  • Nam, Sang-Hyun;Kwak, Moon-Kyu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.257-262
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    • 2000
  • This research is concerned with the active vibration control of slewing smart structures subjected to rotating disturbance. When cantilever beam rotates about axes perpendicular to the undeformed beam's longitudinal axis, it experiences inertial loading. Hence, the beam vibrates after the slewing ends. In this paper, the analytical model for a single slewing flexible beam with surface bonded piezoelectric sensor and actuator is developed using the Hamilton's principle with discretization by the assumed mode method. The theoretial model is verified by the experimental open loop frequency response data. The controller is designed for residual vibration suppression after slewing. The designed cotroller is a positive position feedback (PPF) controller for controlling the first mode vibration.

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