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개폐식 3방향 전자밸브의 펄스폭 변조 구동에 의한 압력제어 특성에 관한 연구
정헌술,Jeong, Heon-Sul 대한기계학회 1997 大韓機械學會論文集A Vol.21 No.3
Pressure control is possible driving a simple ON/OFF 3-way valve of hydraulic servo system by pulse width modulation signal. But the pressure varies according to the duty ratio and carrier frequency and repeated on-off action induces pressure fluctuation. So equations for mean pressure and ripple amplitude are theoretically derived as a function of on/off time, the system parameters which decide the pressure characteristics are arranged and they are verified by experimental study. As the result selection criteria for the major design parameters are established and the basic strategy to suppress the unnecessary fluctuation can be provided for a hydraulic pressure control system using these type of valves.
동적 구속조건을 적용한 자동변속장치의 효과적인 시뮬레이션방법에 관한 연구
정헌술,이교일,Jeong, Heon-Sul,Lee, Kyo-Ill 대한기계학회 1998 大韓機械學會論文集A Vol.22 No.3
Degree-Of-Freedom(DOF) for most power transmission system varies according to the operation status which consists of friction elements to change the power flow or to adjust the speed ratio such as clutches, brakes or one-way clutches. To simulate the dynamic characteristics of automatic power transmission system which is a typical example of such a variable DOF systems, many sets of governing equations and complicated phase decision routines are necessary. In this paper dynamic constraint theorem is derived explaining the torque transmission characteristics during the clutch engagement process and a robust stable algorithm is developed describing this phase transition phenomenon effectively by introducing the concept of direct torque and virtual damping. Finally, applying this algorithm to a passenger car automatic transmission gear consisting of several friction elements, an efficient simulation methods for such a complex system will be suggested that is very simple and systematic.
유압 블리드-오프 회로의 특성 재검토 및 실험적 동특성 모델링
정헌술,이광헌,김형의,Jeong, Heon-Sul,Lee, Gwang-Heon,Kim, Hyeong-Ui 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.8
Meter-in, meter-out and bleed-off circuits are widely utilized in order to adjust the speed of a hydraulic actuator by using a flow control valve and in order to regulate the pressure of a hydraulic volume by using a simple on-off valve. In these circuits, a relief valve serves either to maintain constant system pressure or to protect the system from over-pressure loading. The relief valve of a bleed-off circuit is the second case frequently undergoing on-off action during operation. It makes the analysis of the pressure control characteristics of the circuit highly difficult. In this paper, steady-state flow rate, pressure, heat loss and efficiency of the three circuits are reexamined and basic experiments far obtaining the characteristics of a pump and relief valve are conducted. Finally, simple empirical first-order dynamic models of decreasing and increasing pressure were separately proposed and verified by comparison with experiment. As the result, the basis for the theoretical analysis of the pressure control characteristics of a bleed-off circuit using a simple on-off valve is established.
정헌술,김형의,Jeong, Heon-Sul,Kim, Hyoung-Eui 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.8
By way of driving a 2-way on/off solenoid hydraulic valve with a pulse width modulation (PWM) signal, control of the pressure in a certain volume is frequently used in various applications. However, the pressure built-up according to the duty ratio and carrier frequency of the PWM signal is not so well understood. In order to clarify the characteristics of 2-way valve hydraulic pressure control systems, in this paper two formula fur the mean and ripple of the load pressure were derived through theoretical analysis. And the accuracy of the derived formula were verified by comparison with the experimental test result. Generally 2-way valve systems are constructed as a bleed-off circuit, while 3-way valves are used as a control element in a meter-in circuit pressure control system. In a bleed-off circuit, the system supply pressure from a hydraulic power pack does not remain constant, but changes according to their external load. In turn, the relief valve in the hydraulic power pack reacts accordingly showing complicated dynamic behavior, which makes an analytical study difficult. In order to resolve the problem, simple but accurate empirical dynamic models fer a bleed-off system were used in the course of formula derivation. As the result, selection criteria for two major control parameters of the driving signal is established and the basic strategy to suppress the unnecessary pressure fluctuation can be provided for a hydraulic pressure control system using a 2-way on/off solenoid valve.
정헌술(Heon-Sul Jeong),정승욱(Seung-Wook Jeong) 유공압건설기계학회 2009 유공압건설기계학회 학술대회논문집 Vol.2009 No.11
Hydraulic systems are widely used as a power transfer and/or power control system due to its flexibility, controllability, accuracy and high power density. Valve controlled and/or pump controlled systems are normally was adopted as a control device, but nowadays motor controlled systems are emerging as new energy-efficient hydraulic control systems. In this paper the motor controlled system for the cylinder position control of a counter balance circuit is investigated by using AMESim simulation study. And position control experiments was carried out verifying the possibility and efficiency of the motor controlled system.
정헌술(Heon-Sul Jeong),남지우(Ji-Woo Nam),한성민(Sung-Min Han),한종대(Jong-Dae Han),권순우(Soon-Woo Kwon) 유공압건설기계학회 2010 유공압건설기계학회 학술대회논문집 Vol.2010 No.10
Because of the increasing demand on the high precision and high response of a machinery, proportional control valves are widely adopted at various application fields. This paper studies on the static and dynamic characteristics of a Multi-stage proportional pressure control valve. An experimental apparatus including hydraulic pump, variable speed inverter, pressure and flow sensors and data aquisition system was set up. And various experiments such as P-V-Q curves, step responses due to input voltage and flow rate, hysteresis, frequency response of the proportional valve was carried out and the results are discussed.
[동력전단계부문] 자동변속기 변속특성 및 유연변속의 이론적 해석
정헌술(Heon-Sul Jeong),박진성(Jin-Sung Park),이교일(Kyo-Ill Lee) 한국자동차공학회 1999 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Current torque sensors are too expensive to be used for controller on production vehicle. To provide a basic strategy for smooth jerk shift by usage of RPM sensors only and to accomplish the shift within the designated time for clutch life, detail analysis of shift characteristics was studied. Finally The desired trajectory of slip speed was proposed for indirect jerk shift and clutch torque related with this trajectory was derived which can be used as a controller.
파일럿 비례압력제어밸브의 정특성 및 동특성에 관한 실험적 분석
정헌술(Heon-sul Jeong),남지우(Ji-woo Nam) 유공압건설기계학회 2011 드라이브·컨트롤 Vol.8 No.4
Because of the increasing demand on the high precision and high response of a machinery, proportional control valves are widely adopted at various application fields. This paper studies on the static and dynamic characteristics of a pilot proportional pressure control valve. An experimental apparatus including hydraulic pump, variable speed inverter, pressure and flow sensors and data aquisition system was set up. And various experiments such as P-Q-V curves, step responses due to input voltage and flow rate, hysteresis, frequency response of the proportional valve was carried out and the results are discussed.
정헌술(Heon-sul Jeong),남지우(Ji-woo Nam),임효준(Hyo-joon Lim),정승욱(Seung-wook Jung),한성민(Sung-min Han) 유공압건설기계학회 2010 유공압건설기계학회 학술대회논문집 Vol.2010 No.6
Because of the increasing demand on the high precision and high response of a machinery, electronic control valves are widely adopted at various application fields. This paper studies on the static characteristic of a first-stage proportional pressure control valve. At first an experimental apparatus including hyd. pump variable speed inverter, pressure and data aquisition system was setted up with the experimental apparatus, various tests such as P-Q-W test, hyd, pump, dynamic, static, frequency response test of the proportional valve was carride out and the results are discussed.