• Title/Summary/Keyword: proportional control valve

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Development of a constant pressure feed system using a constant pressure proportional control mode (정압비례제어방식을 적용한 정압급수장치의 개발)

  • 김주명;김광열;이건기
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.5
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    • pp.1026-1031
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    • 2003
  • Automatic feed pumps are operated and stopped by a pressure switch. Thus, because of repeated operations and stops of the pumps according to fluctuations of water volume, operation with constant rate and pressure is impossible. Moreover, because of repeated running of the pump, keeping up of constant pressure is impossible and damage and energy loss are weak points of the pimps. To make up for defects of an automatic feed pump, this paper designed and made a static pressure feed system which was composed of a feed water control valve, a flow sensor and a control system. The valve device plays an important part in reducing load of pumps by constant water supply regardless of outflow of water. Outflow of water is determined by infrared diode of the flow sensor. The control system is made of a 8 bit micro-processor and the pump was controled by a specific control algorithm. With the constant pressure feed system, discharge pressure was kept at fixed pressure, accurate operations and stops were smoothly accomplished and the pump was operated with constant pressure. Thus, the constant pressure feed system can be considered as an advanced system which made up for the weak points in the current automatic feed systems.

A Development of Forklift Shift and Constant Speed Endurance Test Controller for Dynamometer Test (다이나모 시험용 지게차 변속 및 정속 내구시험 제어기 개발)

  • Jung, G.H.;Lee, G.H.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.4 no.3
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    • pp.13-21
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    • 2007
  • A forklift is a motive machine powered by LPG, diesel engine or electric motors. The internal combustion engine type forklift is equipped with automatic transmission to meet the required drive load as well as the easy operation of the vehicle. This paper deals with the shift control and endurance test controller which is developed for the functional test of the newly designed automatic transmission on a dynamometer test bench. Its major function is to control the proportional solenoid currents, which is directly related to clutch pressures, for the given reference current trajectory during shift and sequential operation of shift schedule designed for the durability test at each gear. It also has the ability to monitor all the necessary test data through RS232 communication and log them to disk files. The current controller of embedded system is designed from the identified dynamics of solenoid coil and the current reference can be easily modified with a user interface software on PC so as to match the shift data by experiments.

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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.

Motion Control of a Single Rod Cylinder-Load System Driven by a Proportional Directional Control Valve (비례방향제어밸브에 의해 구동되는 차동 실린더 부하계의 운동제어)

  • Lee, M.W.;Cho, S.H.
    • 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.

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Development of a Tracked Vehicle Model for Real-time Simulation of Semi-active Suspension System (반능동 현수장치의 실시간 시뮬레이션용 궤도차량 모델 개발)

  • 손영일;이종호;송병석
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.4
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    • pp.135-143
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    • 2003
  • In this study, a real-time simulation model was developed for tracked vehicles with in-arm type semi-active hydro-pneumatic suspension unit using MATLAB S-functions. Since the vehicle model uses relative coordinates and massless link elements, the developed model has an enhanced analytic time performance. Through the comparison of simulation results with multi-body software(DADS), the vehicle model is verified. A controller using on-off skyhook control algorithm is designed with the pilot-centre]led proportional valve based on conventional damper characteristics. Exploiting the developed tracked vehicle model with other subsystem model such as a controller model, a suspension unit model, and a test road model, computer simulations are carried out. Control simulation results with the developed tracked vehicle model show that the semi-active suspension control system has a better performance than the conventional suspension system.

Study on Flow-Shifted Region Depending on Spool Displacement in Hydraulic Servo Valve with Hybrid Lap (하이브리드 랩 방식 유압 서보 밸브의 스풀 변위에 따른 유동 천이 영역에 대한 연구)

  • Jeong, Hwang-Hun;Yun, So-Nam;Lee, Sung-Soo;Yang, Joo-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.37 no.3
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    • pp.213-219
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    • 2013
  • This study examined the static characteristics of a spool valve with a hybrid lap between the spool land and the sleeve. The static equation for the pressure characteristics was derived from flow equations that depend on the spool displacement, and the final model was derived from $q_a=q_b=0$ because the pressure characteristics test needs to block the control port in the valve. The static equation for the flow characteristics was derived from the pressure characteristics when the control port is open ($q_a=q_b$, $p_a=p_b$). The characteristic equation in the shifted region was assumed from the proportional relationship between the pressure-flow characteristics and the spool displacement.

Design and experiment with a plastic mulch wrapper using a hydraulic system

  • Park, Hyo Je;Lee, Sang Yoon;Park, Yong Hyun;Kim, Young Keun;Choi, Il Su;Nam, Young Jo;Kweon, Gi Young
    • Korean Journal of Agricultural Science
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    • v.47 no.1
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    • pp.43-58
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    • 2020
  • Mulching plastic is used for the purpose of maintaining soil temperature, moisture, and weed and pest prevention in agriculture. Any remaining plastic after use may contaminate the soil and damage crop growth. To solve this problem, mulching plastic wrappers have been studied and developed, but the actual use rate is quite low due to their poor performance and frequent tearing of the plastic on the field. In this study, we developed a tractor attachable mulching plastic wrapper to minimize the tearing of the mulched plastic. The developed mulching plastic wrapper consists of hydraulic motors and pumps, valves, a microcontroller, and sensors. The collecting speed of the plastic mulch was calculated considering the tractor's travel speed and the radius of the collecting drum. A proportional controller was designed to control the rotating speed of the hydraulic motor as the plastic was wound around the collection drum and the radius increased. The performance of an indoor experiment was quite promising because the difference between the collecting speed predicted by the calculation and the actual collecting speed was 2.71 rpm. Based on a field verification test, the speed difference was max. 14.28 rpm; thus, the, proportional integral derivative (PID) controller needs to be considered to control the drum speed precisely. Another issue was found when the soil covered at the edge of the plastic was hardened or the road surface was uneven, the speed control was unstable, and the plastic was torn. In future research, vibrational plows will be equipped to break-up the harden soil for collecting the plastic smoothly.

Nonlinear adaptive control of a quarter car active suspension (1/4 차 능동현가계의 비선형 적응제어)

  • Kim, Eung-Seok
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.45 no.4
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    • pp.582-589
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    • 1996
  • In this paper, an adaptive control problem of a hydraulic actuator for vehicle active suspension controller is divided into two parts: the inner loop controller and the outer loop controller. Inner loop controller, which is a nonlinear adaptive controller, is designed to control the force generated by the nonlinear hydraulic actuator acting under the effects of Coulomb friction. For simplicity of designing a nonlinear controller, the spool valve dynamics of a hydraulic actuator is reduced using a singular perturbation technique. The estimation error signal used to an indirect parameter adaptation is calculated without a regressor filtering. The absolute velocity of a sprung mass will be damped down by its negatively proportional term(sky-hook damper) adopted as an outer loop controller. Simulation results are presented to show the importance of controlling the actuator force and the validity of the proposed adaptive controller. (author). refs., figs. tab.

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A Control of CVT Hydraulic System using Embedded System (임베디드 시스템을 이용한 CVT 유압시스템 제어)

  • Han, K.W.;Ryu, W.S.;Jang, I.G.;Jean, J.W.;Kim, H.S.;Hwang, S.H.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.4 no.1
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    • pp.18-24
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    • 2007
  • The continuously variable transmission (CVT) of which speed ratio can change continuously in a fixed range has the benefits of low fuel consumption and exhaust gas because it enables the engine of a vehicle to operate in a high efficiency range regardless of vehicle speed. The speed ratio of belt type CVT is controlled by adjusting line pressure. The one of the line pressure control methods, mechanical-hydraulic control is usually adopting VDT's control method, in which the secondary solenoid valve has two functions both a regulator and a line pressure controller. However, this control method could not show the high performance of CVT with optimal driving capability because of the limitation of simple control algorithm, and it could not gain market share sufficiently in spite of the advantage of CVT with low fuel consumption. On the other hand, the electro-hydraulic control method gives the enhancement of power performance and low fuel consumption by implementing various driving mode using the proportional control or PWM control. The key of CVT technique is to develop a control algorithm of the electro-hydraulic solenoid valve in order to implement the speed ratio efficiently. In this paper, the line pressure control algorithm is proposed and the hydraulic system is controlled using metal belt type CVT test rig and the embedded ECU platform.

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Laboratory Test on Total Flow Control for Ice Slurry System with Inverter Fed Motor Pump (인버터구동 모터펌프를 이용한 아이스 슬러리형 빙축열시스템 전유량제어 운전시험)

  • Choi, Byoung-Youn;Lee, Kyoung-Ho;Lee, Sang-Ryoul;Lee, Hak-Joo
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.260-265
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    • 2001
  • This paper describes total flow control of an ice slurry system for pump energy saving. Similar turbo machinery has a characteristic that input power ratio is proportional to the three time of revolution speed ratio. To reduce the energy cost of brine pump in ice slurry storage systems, inverter is adapted instead of 3-way valve to control the speed of brine pump motor. One type of cooling load profile was used as driving load of the system, generated by a boiler and warm water storage tank. As results of the laboratory test, energy consumption and cost of the pump were reduced by 11.4%.

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