• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.404-408
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• 2013

In this Study, another way to accomplish the goal of meeting large steam-flow requirements is the use of multiple valves. Multiple valves can provide better control in meeting the precision pressure controller requirements. Simulation demonstrates the effectiveness of the pressure controller. The key point of this study is to precisely control the position of the control valve on the outside of the electro-hydraulic system using a special PID controller. Simulation and experiments verify the performance of the controller.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.54-59
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• 1994

In this study, a high-speed servo valve with no outer leakage is developed, which is used to drive flexible hydraulic actuators (FHA) for extreme environments. In the valve, multilayered PZT devices are used to drive a spool directly and quickly. A bellows is also used to prevent outer leak from the clearance between the spool and the sleeve. Employing a disturbance observer, the lack of the system damping of the valve is improved by feeding back the estimated velocity of the spool, as well as the estimated disturbance is fed back to eliminate effectively the hysteresis between input voltage and output displacement of the PZT devices.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.170.1-170
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• 2001

This paper developed the model for electro hydraulic force control system by identification method via ARMAX model. Implementation of Identification is performed on Pin-On-Disk type tribotester. The wear mechanism is an important mechanic property to select a material´s life and a optimum work condition. Pin-on-disk type tribotester is popular wear analysis experimental equipment and its mechanism is that adding a force on a rotating disk to simplify two surface contact´s wear experimental condition. Material´s rotating velocity and eccentricity rotation makes disturbance and it affects adding constant force. To get a high performance of force adding part, DDV(Direct Drive Valve) which has pressure control loop is used. To obtain a tribotester´ s ARMAX model, prediction error method(PEM) is used in case force adding part and rotating part is ...

• Journal of Mechanical Science and Technology
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• v.16 no.3
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• pp.283-291
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• 2002

The paper demonstrates the tracking performance of a sliding horizon feedback/feedforward preview optimal control when applied to a hydraulic motion simulator which has been built to provide a means of replicating the actual ride dynamics of an automobile seat/human system. The design was developed by solving an ordinary differential equation problem instead of a Ricatti equation. Simulation results indicate that the proposed technique has good performance improvement in phase tracking when compared to the classical design methods. It is also found that the controller can be adjusted more easily for robustness due to more tuning parameters.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.472-475
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• 2005

In this paper, we propose a Kalman-fuzzy control method using multi-sensor. The proposed method is to obtain a robust sensor data and to integrate multi-sensor data using fuzzy system. in order to verify the effectiveness of the proposed method, we performed the simulation for the position of an elertro hydraulic actuator. The results showed a good performance.

• Transactions of The Korea Fluid Power Systems Society
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• v.2 no.3
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• pp.1-5
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• 2005

There are two types of solenoid actuator for force and position control of the fluid power system. One is an on-off solenoid actuator and the other is an electro-magnetic proportional actuator. They have some different characteristics for attraction force according to solenoid shape. Attraction force of the on-off solenoid actuator only depends on flux density. And the stroke-force characteristics of the proportional solenoid actuator are determined by the shape of the control cone. In this paper, steady state characteristics of the solenoid actuator for electro-hydraulic proportional valve determined by the shape of control cone are analyzed using finite element method and it is confirmed that the proportional solenoid actuator has a constant attractive force in the control region independently on the stroke position. And the shape of control cone is optimized using 1+1 evolution strategy to get a constant force. In the optimization algorithm, control cone length, thickness and taper length are used as a design parameter.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.321-324
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• 2002

Hydraulic valve control the pressure and the How of fluid by the hydraulic oil transfered from pump but the ER fluid consists of solid particles of micrometer in size and insulating oil so in the general hydraulic valve. We invented ER-Valve using ER fluid as working fluid. The ER fluid, working fluid of ER-Valve is a functional fluid to represent the feature of fluid according to strength of electric field. In this research we made our own 4 types of plate type ER-Valve which has same surface but different width and length and then we conducted performance test. We measured flow rate and pressure drop of fluid which is flowing in the ER-Valve according to the electric field strength to conduct this test. We modeling ER-Valve relating to ER-Valve system and yield shear stress according to the strength of electric field. We used the pressure drop according to the strength of electric field by differential pressure gauge in the our own made ER-Valve. This test reviewed experimental the special changes of ER-Fluid in the steady flow condition.

• Journal of Mechanical Science and Technology
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• v.19 no.8
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• pp.1621-1631
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• 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.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.6
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• pp.567-572
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• 2009

The underwater launch system using an ATP consists of five parts: compressor tank, proportional flow control servo valve, expulsion spool valve, air turbine pump, and discharge tube. The purpose of this study is to develop an underwater launch system using an ATP and to verify the validity of the system. The proportional flow control servo valve is modeled as a 2nd order transfer function. The projectile is ejected by pressurized water through the air turbine pump, which is controlled by expulsion valve. The mathematical model is derived to estimate the dynamic characteristics of the system, and the important design parameters are derived by using simulations. The computer simulation results show the dynamic characteristics and the possibility of control for underwater launch system.

• International Journal of Automotive Technology
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• v.6 no.4
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• pp.391-402
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• 2005

Despite its superior braking performance to conventional vehicles on test tracks, the performance of the ABS-equipped car seems disappointing on real highway. The poor braking performance results from questionable design of the human-machine interface(HMI) of the brake system. Force-displacement relation at the brake pedal has a strong effect on the braking performance. Recently developed brake-by-wire (BBW) system may allow us to tailor the force feel at the brake pedal. This study aims at exploring analytical ways of designing human-machine interface of BBW system. In this paper, mathematical models of brake pedal feel for electro-hydraulic BBW (EH-BBW) system are developed, and the braking motion and the characteristics of the driver's leg action are modeled. Based on the dynamic characteristics of the brake pedal and the driver, two new HMI designs for EH-BBW system are proposed. In the designs, BBW system is modeled as a type of master-slave teleoperator. The effectiveness of the proposed designs is investigated using driving simulation.