• Journal of Advanced Marine Engineering and Technology
• /
• 제15권4호
• /
• pp.54-69
• /
• 1991

This study deals with the position control of a hydraulic cylinder system operated by two port 3-way high speed solenoid valve in Pulse-Width-Modulation mode, instead of using conventional electro-hydraulic servovalve. Due to the complexity and the relatively poor reliability of the servovalve, an actuator using simpler and more study high speed solenoid valve will be presented. The high speed solenoid valve acts as converters of electronic pulse signal to hydraulic ones. It has been pointed out that there are practical problems to be solved in the PWM system, that is (1) accuracy of positioning control becomes considerably insufficient because the system is affected by on/off action of the solenoid valves, and (2) serious nonlinerality appears in the valve characteristics as a result of the switching behavior of the valves. As a method to overcome these defects, the differential PWM driving method of a hydraulic cylinder that improved the steady-state-error, flow rate nonlinearity in simple PWM, and the hydraulic hunting of dead time compensated-PWM driving is proposed in this study.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2009년도 제40회 하계학술대회
• /
• pp.824_825
• /
• 2009

This paper deals with the characteristics of SPMSM for hydraulic actuator according to the slot number. As a design variable, slot number affects the winding configuration and this leads to the total variation of motor characteristic. Therefore number of slot should be cautiously determined. Three SPMSMs are designed and THD of back emf, cogging torque, and torque ripple are compared. Among three SPMSMs, 36slots with 12 pole is chosen for further development considering motor characteristics and manufacturing.

• 대한기계학회논문집
• /
• 제8권2호
• /
• pp.104-110
• /
• 1984

본 연구에서는 유압식 방법보다 절삭 정밀도가 높고 전기신호를 사용함으로 인한 조작과 증폭이 간단하고 특성 개선을 위한 조작과 증폭이 간단하고 특성 개선을 위한 계의 보상(sysyem compensation)을 할 수 있는 전기 유압식 모방장치를 설계, 제 작하여 그 성능을 실험적으로 해석하였다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2008년도 춘계학술대회논문집
• /
• pp.171-176
• /
• 2008

Active suspension controls stiffness and damping between unsprung mass and sprung mass in order to increase the ride quality. However, to increase the riding quality, the handling quality should be decreased and the rattle space should be increased. So, active suspension should cope with these conflict conditions. Therefore its actuating devices have to produce sufficient actuating force and have sufficiently short response time. In this paper, the dynamic characteristics of 1/4 car model with an active suspension is studied according to hydraulic design variables. The active suspension consists of a hydraulic servo valve and a hydraulic cylinder. It shows better performance when it has more powerful and faster actuator.

• Journal of Advanced Marine Engineering and Technology
• /
• 제23권1호
• /
• pp.69-78
• /
• 1999

In this study a new pattern of pressure control of hydraulic cylinder using high speed On-Off solenoid valve in the electro-hydraulic system has been suggested. The control valve is 3-way high speed On-Off solenoid valve which is operated by PWM(Pulse Width Modulation)control signal. The high speed On-Off solenoid valve has a tendency to induce severe pressure fluctuation in the hydraulic actuator so it has not been used for the purpose of closed loop control with direct pres-sure feedback. In this study closed loop control with direct pressure feedback is enabled by using a digital filter which has linear minimum mean square filter algorithm. Through some experiments it is confirmed that stable pressure control can be realized by the proposed control technique.

• 한국추진공학회지
• /
• 제14권6호
• /
• pp.89-102
• /
• 2010

본 논문에서는 항공우주분야의 구동장치와 여러 산업분야에서 응용되고 있는 미래 지향적 구동기의 기술에 대한 사항과 발전방향에 대해 연구하였다. 특히, 항공기 비행조종면 구동장치의 경우 기존에는 기계식 링키지나 무게 대비 출력이 높은 유 공압 구동기가 많이 사용되었으나 최근에는 대부분의 항공기에서 사용 중인 Fly-By-Wire 시스템과 더 나아가 'More Electric', 'All Electric' 시스템으로의 변화가 이루어지고 있다. 전기식 유압구동기와 전기식 구동장치의 경우 효율이나 안전성 그리고 비용적인 측면에서 우수하기 때문에 근래에 지속적인 개발이 진행되고 있다. 또한, 최근에는 구동기의 무게와 정밀도 그리고 응답속도의 향상을 위해 신소재를 이용한 새로운 분야의 구동기들이 개발되고 있다. 따라서 본 연구를 통해서 차세대 항공우주분야 구동장치와 신개념 구동기들의 세부기술 및 발전방향을 제시하고자 한다.

• Journal of Mechanical Science and Technology
• /
• 제19권8호
• /
• pp.1621-1631
• /
• 2005

In this paper, making the best use of the features of the electro-rheological (ER) valve, a two-port pressure control valve using ER fluids is proposed and manufactured. The ER-Valve characteristics are evaluated by changing the intensity of the electric field and the number of electrode. As only with electrical signal change to the ER-Valve in which ER fluid flowing, ER fluid flow is controlled, so development of simple ER-Valves have been tried. The ER-Valves and pressure drop check method are considered to be applied to the fluid power industry. Using the manufactured pressure control valve, a one-link manipulator with FHA (Flexible Hydraulic Actuator) is driven. As a result, it is experimentally confirmed that the pressure control valve using ER fluids is applicable to use in driving actuator. If it applies characteristics of the ER fluids, it will be able to apply in the control system for the ER Valve which occurs from industrial controller. After having durability test, shear stress increased regularly because of starch particles crushed by pump and particle size that was almost the same. Moreover, Ra of copper electrode increased about 1.56 times rather than before those of performing durability test, and Rz increased about 2.2 times.

• 드라이브 ㆍ 컨트롤
• /
• 제16권2호
• /
• pp.30-35
• /
• 2019

EPPR (Electro-hydraulic Proportional Pressure Reducing) valves are pressure control valves. In this study, an independent metering valve (IMV), which is a combination of a spool valve opened and closed with the help of an EPPR valve, was discussed. The overall performance of the valve (IMV) was obtained by the respective modeling and simulation of the system. The valve investigated in this study is to be used for independent metering of hydraulic excavator actuator e.g. boom, arm, bucket etc. To design the model, continuity equations and force balance equations were used. The set of differential equations were then simulated in Simulink using ODE45 option in the configuration toolbox. The valve has to be able to control the flow rate going in and out of the cylinder separately, which is why the particular configuration was needed and selected.

• 한국자동차공학회논문집
• /
• 제19권6호
• /
• pp.140-147
• /
• 2011

The injection nozzle of an electro-hydraulic injector for the common rail Diesel fuel injection system is being opened and closed by movement of a injector's needle which is balanced by pressure at the nozzle seat and at the needle control chamber, at the opposite end of the needle. In this study, the slenoid actuator was considered as a prime movers in high pressure Diesel injector. Namely a solenoid-driven Diesel injector with different driving current types, as a general method driven by solenoid coil energy, has been applied with a purpose to develop the analysis model of the solenoid actuator to predict the dynamics characteristics of the hydraulic component (injector) by using the AMESim code. Aimed at simulating the hydraulic behavior of the solenoid-driven injector, the circuit model has been developed as a unified approach to mechanical modeling in this study. As this analytic results, we know the suction force and first order time lag for driving force can be endowed in solenoid-driven injector in controlling the injection rate. Also it can predict that the input current wave exerted on solenoid coil is the dominant factor which affects on the initial needle behavior of solenoid-driven injector than the hydraulic force generated by the constant injection pressure.

• 드라이브 ㆍ 컨트롤
• /
• 제13권3호
• /
• pp.32-38
• /
• 2016

For this paper, the position-control performances of dual EHA(electro-hydrostatic actuator) systems were investigated according to two cases wherein the double-rod- and single-rod-type hydraulic cylinders were combined. Since the control performance is significantly dependent on the load conditions including external forces such as the inertia load, it is proposed here that the two sub-EHAs are driven by separate position and force controllers, instead of two identical position controllers. According to the simulation results, the best performance was achieved by the position-controlled single-rod-type EHA that was combined with a force-controlled double-rod-type EHA. As the force-controlled double-rod-type EHA compensated for the external loads on the position-controlled single-rod-type EHA, the position-control performance was not influenced by external forces including the inertia load. In addition, the position-controlled single-rod-type EHA contributed to the enhancement of the damping ratio by absorbing the pressure peaks through its internal accumulator. Due to the symmetrical piston areas, the double-rod-type EHA is more suitable for force control than the single-rod- type EHA.