• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.415-420
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• 2012

This paper proposes a novel type of tactile device utilizing magnetorheological (MR) fluid which can be applicable for haptic master of minimally invasive surgery (MIS) robotic system. The salient feature of the controllability of rheological properties by the intensity of the magnetic field (or current) makes this potential candidate of the tactile device. As a first step, an appropriate size of the tactile device is designed and manufactured via magnetic analysis. Secondly, in order to determine proper input magnetic field the repulsive forces of the real body parts such as hand and neck are measured. Subsequently, the repulsive forces of the tactile device are measured by dividing 5 areas. The final step of this work is to obtain desired force in real implementation. Thus, in order to demonstrate this goal a neuro-fuzzy logic is applied to get the desired repulsive force and the error between the desired and actual force is evaluated.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.6
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• pp.578-586
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• 2009

Recently, horn-type rudders are generally being used at high speed container ships and are frequently suffering from the cavitation occurs on the rudder surface in the vicinity of the gap between the horn and rudder plate. In the present study, a fluid supplying device is employed as to decrease the gap cavitation of the horn-type rudder. The device is devised to inject the water against the pressure side through the nozzle installed inside of the gap to control the gap flow. Numerical calculations are performed to investigate the effectiveness of the device and the results show that the device can noticeably reduce the gap cavitation. The rates of water injection for achievement of the maximum retardations of gap flow are also sought.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.1
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• pp.57-63
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• 2009

Magneto-Rheological(MR) fluid composes of a base fluid and ferromagnetic particles less than tens of micrometer size dispersed in the fluid. It is called as a smart material because its rheological properties are changable by a magnetic field. Its important applications are active devices such as controllable dampers and controllable clutches. The merit of those products is that their functional characteristics are controllable such that they enable active control strategies. This paper proposes an idea for machine tool applications of the MR fluid clutch as a safety device for power transmission. FEM has been used for magnetic field analyses and the results are compared with some former experiments. Some design syntheses of the MR clutches are suggested and hopefully considered that it may be an effective safety device for power transmission of machine tools.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.3
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• pp.207-211
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• 2010

In this paper, the fluid AID(acoustic inspection device) was developed to measure SOS(speed of sound) since fluids used in most of industrial fields have different properties and its equipment is highly expensive. From AID developed, it is intended to get potentially the capability to distinguish the kind of fluid using the measurement by the SOS at various fields. In order to measure the sound speed of specific fluids, the measurement system and ultrasonic sensors are composed. The fluid used in the experimental work are soybean oil, glycerin, diesel oil and the error of time difference due to the container wall is extracted for preliminary experiment. As results, the variations of sound speed according to the temperature change of target fluid were analyzed and the polynomial equations were proposed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1997.04a
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• pp.151-166
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• 1997

ER clutch is a device using ER fluid, so called "intelligent material" and is a controlled system with electric field strength. Current problem of this device is that the temperature of ER fluid increases when ER clutch is operating and affects the performance of ER clutch. This study was undertaken to estimate this performance variation due to temperature increase of ER fluid. Analytic power transmission relationships and the temperature increase model using the rheological model of ER fluid were developed and the dynamic model of proposed ER clutch system was constructed, also. With this relationships, effects of changing geometric, kinetic parameters of ER clutch and ER fluid properties were described and performance variations due to temperature increases of ER fluid were estimated. In conclusion, compared with neglecting temperature increase effects, a performance of ER clutch was very differential. Therefore, to achieve uniform performance of ER clutch, we have to improve thermal stability of ER fluid with a view point of material development and design carefully ER clutch considering temperature increase effects with a view point of mechanical design skill.ign skill.

• The KSFM Journal of Fluid Machinery
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• v.8 no.2 s.29
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• pp.68-71
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• 2005

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.5
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• pp.516-522
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• 2009

This paper proposes a new haptic cue vehicle accelerator pedal device using magnetorheological(MR) brake. As a first step, an MR fluid-based haptic cue device is devised to be capable of rotary motion of accelerator pedal. Under consideration of spatial limitation, design parameters are optimally determined to maximize control torque using finite element method. The proposed haptic cue device is then manufactured and integrated with accelerator pedal. Its field-dependant torque is experimentally evaluated. Vehicle system emulating gear shifting and engine speed is constructed in virtual environment and communicated with the haptic cue device. Haptic cue algorithm using the feed-forward control algorithm is formulated to achieve optimal gear shifting in driving. Control performances are experimentally evaluated via feed-forward control strategy and presented in time domain.

• Transactions of The Korea Fluid Power Systems Society
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• v.7 no.1
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• pp.6-10
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• 2010

A measurement of very high torque for track drive unit in construction equipment is usually in difficulties due to the requirement of a torque meter with high capacity, and the limitation of geometry for an experimental set-up. To improve the troublesome problem, a new device was proposed, where a torque transmitted through the torque arm can be measured by load cells attached at each torque arm. The experimental set-up of the new device was carried out in order to measure the torque values for a mechanical feedback type planetary gear box, in which the power flow circulates itself in a closed-loop. The new device enables to measure torque values of 60,000Nm. Additionally, the measured values were estimated statistically in the aspect of their repeatability and reproducibility, so that an acceptable behaviour as a measuring device can be confirmed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.627-632
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• 2009

This paper proposes a new haptic cue vehicle accelerator pedal device using magnetorheological (MR) brake. As a first step, an MR fluid-based haptic cue device is devised to be capable of rotary motion of accelerator pedal. Under consideration of spatial limitation, design parameters are optimally determined to maximize control torque using finite element method. The proposed haptic cue device is then manufactured and integrated with accelerator pedal. Its field-dependant torque is experimentally evaluated. Vehicle system emulating gear shifting and engine speed is constructed in virtual environment and communicated with the haptic cue device. Haptic cue algorithm using the feed-forward control algorithm is formulated to achieve optimal gear shifting in driving. Control performances are experimentally evaluated via feed-forward control strategy and presented in time domain.

• Structural Engineering and Mechanics
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• v.5 no.2
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• pp.177-191
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• 1997

In the paper, a fractional derivative Kelvin-Voigt model describing the dynamic behavior of a special class of fluid viscous dampers, is presented. First of all, in order to verify their mechanical properties, two devices were tested the former behaving as a pure damper (PD device), whereas the latter as an elastic-damping device (ED device). For both, quasi-static and dynamic tests were carried out under imposed displacement control. Secondarily, in order to describe their cyclical behavior, a model composed by an elastic and a damping element connected in parallel was defined. The elastic force was assumed as a linear function of the displacement whereas the damping one was expressed by a fractional derivative of the displacement. By setting an appropriate numerical algorithm, the model parameters (fractional derivative order, damping coefficient and elastic stiffness) were identified by experimental results. The estimated values allowed to outline the main parameter properties on which depend both the elastic as well as the damping behavior of the considered devices.