• Transactions of The Korea Fluid Power Systems Society
• /
• v.2 no.4
• /
• pp.7-13
• /
• 2005

This paper presents modeling and ostimator/controller design for the hydraulic system in Vehicle Stability Control(VSC) system. A nonlinear mathematical model of the VSC hydraulic system is proposed and its accuracy is experimentally verified. A brake pressure estimator is then designed based on the derived mathematical model of VSC hydraulic system. And a disturbance observer, which compensates the estimation error between the brake pressure and the computed brake pressure is also designed to enhance the accuracy of the estimator. The proposed controller has the form of a feedback controller and determines explicitly the on/off ratio of valves' driving PWM signals by means of making use of the simplified mathematical model in the VSC hydraulic system. The performance of the designed controller whose feedback signal is generated by the brake pressure estimator is validated through experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2010.10a
• /
• pp.421-426
• /
• 2010

With hydraulic noise test facility, a variety of tests were performed to investigate the pulsation pressure generation mechanism and its transmission characteristics and to derive the noise control methodology. Many experiments were carried out by changing average pressure, flow rate, pump speed, hose length and MCV spool condition. From the test results, the correlations between pulsation pressure and other design parameters, such as static pressure, flow rate and MCV spool opening area and length of hose, were found out. And also each contribution factors were evaluated from the regression analysis. By changing hose length, the pulsation pressure resonance phenomenon was investigated. In order to find out the pulsation pressure reduction measures pulsation pressure analysis, such as pulsation pressure of hydraulic pump itself and pulsation pressure of hydraulic system, by using AMESim were studied. In addition hydraulic silencer was developed based on the Helmholtz resonator. And its performance was evaluated by installing the silencer at the excavator.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.21 no.12
• /
• pp.1152-1158
• /
• 2011

In this paper a configuration of the load evaluation device for the tilting actuator using hydraulic power is presented, which makes it possible to measure the force action on the tilting actuator. It is possible to measure only current using the conventional electro-mechanical actuator when the bogie is in the process of the tilting. This makes impossible to measure the force acting on the tilting actuator. In order to overcome this problem a kinetic mechanism test system using hydraulic cylinder is proposed. The system are consisted of hydraulic cylinder for the tilting actuation, control system to control hydraulic power, sensors to measure for force and displacement and monitoring system for the user interface.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.248-252
• /
• 2007

As Waterpower Generation generates electricity using the difference of altitude of water, also let the turbine revolves through water pipe, at this time the revolving turbine causes exceedingly huge noise. Accordingly, not only those workers in the hydraulic turbine dynamo room are suffering the difficulties in mutual communication, but also those workers in the adjacent office are enduring the obstruction to the business due to the noise. Therefore, this Study has analyzed the reduction effect on the noise of hydraulic turbine dynamo room utilizing computer simulation, through the preceding research with the optimized model for architectural acoustic factor of the hydraulic turbine dynamo room. It is considered that such research result could be applied as the useful material for improvement of acoustic performance and noise-reduction effect at other similar hydraulic turbine dynamo room in the future.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2004.11a
• /
• pp.367-371
• /
• 2004

Bio-degradable hydraulic oil using polyolester base oil is formulated for the applications of heavy duty hydraulic machineries. It has proved quality and market price competitiveness by assessment of reliability test in vehicle manufacturer and specific vehicle related institute. Contribution of bio-degradable oil keep the working environment clean and increase export competitiveness in European market. Leakage or waste of mineral types of hydraulic oils in heavy duty machineries causes pollution of river, ocean, underground water. Drinkable-water pollution is serious problem in Europe. In some European countries, using bio-degradable hydraulic oils become an obligation in heavy duty machineries. New product of bio-degradable oils satisfy the European regulations(OECD 302B) and shows excellent performance in compare with European products.

• Journal of Sensor Science and Technology
• /
• v.23 no.1
• /
• pp.19-23
• /
• 2014

A new hydraulic tube structure for WIM sensor of a new generation is presented in this paper. The double-tube structure has been developed in order to improve the performance of the hydraulic load cell. The double-tube structure hydraulic element could be reduced by 46% in pressure changes according to temperature compared to a single-tube structure. In addition to the nonlinearity can be reduced by 67.19% at the same load condition. The hydraulic load cell shows an excellent linearity and measurement accuracy as the result of the static load test.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.10a
• /
• pp.225-230
• /
• 2002

Machine of textiles let off is equipment supplying constantly fabrics. Nowdays, as it is replaced band - brake type with hydraulic motor driven type, we looked into characteristic of hydraulic solenoid pilot direction valve(SPDV) for controlling acceleration performance of hydraulic motor. This study deals with controlling the initial speed of textiles let off machine. Finally, to control the initial speed of hydraulic motor, we controlled the adjustment screw of SPDV by a hand. Test which was carried out in the laboratory shows that initial speed of textiles let off could be improved by controlling adjustment screw of SPDV. Also, the results of experiment work were compared with dynamic characteristic of other on/off solenoid direction valve(SDV).

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.3
• /
• pp.89-96
• /
• 2003

An electro-hydraulic manipulator using hydraulic actuators has many nonlinear abetments, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to realize not only stable but also accurate trajectory control for the autonomous assembly tasks using hydraulic manipulators. In this report, we propose a two-degree-of-freedom control including parallel feedforward compensator (PFC) where PFC plays a very important role in the stability of a proposed control system. In the experimental results of the 6-link electro hydraulic manipulator, it is verified that the stability and the model matching performance are improved by using the proposed control method.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.16 no.1
• /
• pp.166-174
• /
• 2008

Recently, the automotive industry has been developing rapidly. With the progress parts of the automobile components need high quality and the reliability. Among them, braking unit is essential device, and acquire the reliability through the performance test of brake. This study was aimed to design the performance-test-bench to measure the drag torque which has effect on caliper in braking unit. In this progressive technology, it is vital importance to use hydraulic and pneumatic, and to combine test bench with instrumentation engineering technology. This system to construct the design of hydraulic and pneumatic circuit, interface technique between sensors and personal computer, data acquisition and display design, and integrated control are very important technology. Moreover, reliable data are obtained through vacuum system and hydraulic and pneumatic system by using of booster and brake master cylinder which are actually applied to automobile. Then, data signal detector sensors for speed, pressure and torque is attached on this system. Therefore, in this study, we designed a performance-test-bench by and we also made an total control system using personal computer which is more progressive and flexible method than existing PLC control.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.194-194
• /
• 2010

The variable demand on the energy market, as well as the limited energy storage capabilities, requires a great flexibility in operating hydraulic turbines. But, present in Korea, the absence of testing laboratories and technical criteria for the performance test of small hydropower degrades the efficiency of the domestic hydropower machines, A performance guarantees for hydro turbines shall be contain, as a minimum, guarantees covering power, discharge and specific hydraulic energy, efficiency, maximum momentary overspeed and maximum momentary pressure and/or maximum steady-state runaway speed, as well as guarantees related to cavitation. Performance test are conducted by the test standard. Test codes based on extensive research data are written under the leadership of an IEC. Performance evaluation is carry out several test(performance test, cavitation test and runaway test). The paper presents the international turbine test laboratory and performance test standard.