• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.795-796
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• 2013

• Journal of Biosystems Engineering
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• v.26 no.1
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• pp.11-20
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• 2001

Experiments under the stationary and harvesting condition, were performed in order to investigate the vibration characteristics of a head-feeding combine. 6 degrees of freedom components of acceleration at the location of the center of the gravity, and 3 degrees of freedom components of acceleration at the location of the operator seat were measured independently. The vibration characteristics of the combine were estimated with the power spectral density of the time series data of accelerations. From this research, the following results were obtained. 1. Vibration of a head-feeding combine under the stationary condition(engine, thresher and cutter are driven without harvesting) is mainly influenced by the engine. Further, 1/3, 1/2 (sub-harmonic) frequency components of the engine are observed besides engine driving frequency component(45Hz). 2. Vibration of a head-feeding combine under the harvesting condition is influenced by the engine, threshing unit and driving unit. Namely, some kinds of vibration frequency components in harvesting are observed compared with stationary condition. Further, sub-harmonic frequency components of the engine are observed besides engine driving frequency component as same as stationary condition. From these results, it may be concluded that vibration of a head-feeding combine is characteristics of semi-periodic and nonlinear vibration.

• 한국기계연구소 소보
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• s.18
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• pp.99-104
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• 1988

The method of simulation for ballistic feeding mechanical system is presented. Taking photograph of roller drived by a force of explosion, searches the motion of roller. The algorithm that a motion of roller is converted into a motion of cam is presented. Using central difference method, the angular velocity and acceleration of cam is evaluated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.382-386
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• 2002

The tapping is machining process that makes a female screw on the parts to be assembly together. It is used for the high-speed tapping machine with synchronizing function for the high productivity. This paper describes the development of the ultra high-speed tapping machine with 10,000rpm. The key factors in the tapping speed are the acceleration/deceleration velocity and the synchronizing errors between the spindle motor and feeding motor. To minimizing acceleration/deceleration time, the low inertia spindle with synchronous built-in servo motor is developed. To minimizing synchronizing errors, the tapping cycle algorithm under open architecture CNC environment is optimized. The developed tapping machine has 0.13sec/10,000rpm in acceleration/deceleration time and the synchronizing error below 4.0%. It has 0.55sec for cycle time of one female screw, M3 tap, 2 times depth of tap diameter.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.5
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• pp.596-602
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• 2010

In this study, a fmite element model was developed for analysis of feeding a structure in open loop control The finite element analysis (FEA) can simulate dynamic behavior of the structure of a machine tool rapidly traveling with a screw feeding driving system. The feeding mechanism was implemented with screw element of the FEA tool used in this study. The procedure was developed for the dynamic transient FEA. First, motion parameters such as jerk and velocity were introduced for the structure to be fed in open loop control When its traveling distance was determined, set-points for the distance were generated based on the motion parameters. The set-points were applied to the FE model constructed for the traveling structure. The FEA was executed and evaluated. In this study, the FEA procedure was applied to the column of a machine tool and the dynamic behavior of the column was evaluated. The FEA helps in evaluation of the motion characteristics of a structure. The convergence time of the structure vibration posterior to feeding termination can be estimated and the stiffness of the flexible structure is also evaluated against jerk, and acceleration. It provides the feeding force which is helpful in selection of the feeding motor.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.1008-1013
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• 2001

KSR-III propulsion system designed in KARI has a gas-pressurization system for propellant feeding system. This system uses a regulator for the control of the ullage pressure of propellant tank and a venturi for passive control of propellant flowrate. This system seems to be very reliable, but the flowrate of propellant varies according to the change of acceleration with the rocket flight. In this paper, dynamic characteristic of KSR-III propulsion feeding system was analyzed in flight condition. The purpose of this research is to find the variation of off ratio and propellant flowrate change for certification condition of engine reliability test.

• Smart Structures and Systems
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• v.14 no.6
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• pp.1055-1079
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• 2014

Substructure shake table testing is a class of real-time hybrid simulation (RTHS). It combines shake table tests of substructures with real-time computational simulation of the remaining part of the structure to assess dynamic response of the entire structure. Unlike in the conventional hybrid simulation, substructure shake table testing imposes acceleration compatibilities at substructure boundaries. However, acceleration tracking of shake tables is extremely challenging, and it is not possible to produce perfect acceleration tracking without time delay. If responses of the experimental substructure have high correlation with ground accelerations, response errors are inevitably induced by the erroneous input acceleration. Feeding the erroneous responses into the RTHS procedure will deteriorate the simulation results. This study presents a set of techniques to enable reliable substructure shake table testing. The developed techniques include compensation techniques for errors induced by imperfect input acceleration of shake tables, model-based actuator delay compensation with state observer, and force correction to eliminate process and measurement noises. These techniques are experimentally investigated through RTHS using a uni-axial shake table and three-story steel frame structure at the Johns Hopkins University. The simulation results showed that substructure shake table testing with the developed compensation techniques provides an accurate and reliable means to simulate the dynamic responses of the entire structure under earthquake excitations.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.1
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• pp.60-69
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• 2007

Ruminants eating dry forage secrete large volumes of saliva which results in decreased plasma volume (hypovolemia) and the loss of $NaHCO_3$ from the blood. The present research investigated whether or not hypovolemia and the loss of $NaHCO_3$ from the blood in goats brought about by dry forage feeding actually depresses feed intake and saliva secretion, respectively. The present experiment consisted of three treatments (NI, ASI, MI). In the control treatment (NI), a solution was not infused. In the ASI treatment, i.v. infusion of artificial parotid saliva was initiated 1 h before feeding and continued for the entire 2 h feeding period. In the MI treatment, iso-osmotic mannitol solution was infused. The NI treatment showed that hematocrit and plasma total protein concentration were increased due to decreased circulating plasma volume brought about by feeding. In the ASI treatment, the fluid and $NaHCO_3$ that were lost from the blood because of a feeding-induced acceleration of saliva secretion was replenished with an intravenous infusion of artificial parotid saliva. This replenishment lessened the levels of suppression on both feeding and parotid saliva secretion. When only the lost fluid was replenished with an intravenous infusion of iso-osmotic mannitol solution in the MI treatment, the degree of feeding suppression was lessened but the level of saliva secretion suppression was not affected. These results indicate that the marked suppression of feed intake during the initial stages of dry forage feeding was caused by a feeding-induced hypovolemia while the suppression of saliva secretion was brought about by the loss of $NaHCO_3$ from the blood due to increased saliva secretion during the initial stages of feeding.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.4
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• pp.75-82
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• 2001

KSR-III propulsion feeding system is designed to feed a certain amount of propellant to engine by the end of combustion. The oscillation of propellant to engine would cause combustion instability and thrust oscillation and POGO phenomenon. This article deal with analysis performed such as the effect of rocket acceleration on the propulsion system and POGO analysis to ensure the performance of KSR-III

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.292-297
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• 1990

An anti-swing controller for an overhead crane in the stop position is designed. The developed anti-swing controller improves on the poor damping characteristics of overhead crane by feeding back the crane acceleration as a function of swing angular speed. The experimental results show that this crane using the proposed controller yields small stop position error and rapid damping response characteristics.