• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.154-160
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• 2004

Hydraulic breaker of excavator has been used for the destruction and disassembling of buildings, crashing road pavement, breaking rocks at quaky and etc. The performance of breakers is evaluated their own destructive force and the number of impact by input hydraulic flow rate and pressure on the operating conditions. Because hydraulic breakers generate high impact energy, the accurate measurement of the impact force has been facing a technical challenge. In this study, the hydraulic pressure transducer system was developed based on the characteristics of pressure variation in closed vessel fur testing the impact energy. The hydraulic pressure transducer system is consisted with a hydraulic cylinder, main base, pressure & temperature sensors, LVDT, data acquisition system and etc. The developed hydraulic pressure transducer system was applied to measure the impact energy for hydraulic breaker. The measured impact force was 438.8 kgf.m within the designed impact force bounds. The developed hydraulic pressure transducer system as a simple tester could be applied to measure the impact force and the number of impact.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.509-512
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• 2015

In this paper, several capacitive sensors for measuring the position of the piston in hydraulic cylinder was studied and designed. The inductive LVDT sensor has been widely used to measure the position of the piston because of its high accuracy, but this type of sensor is very expensive and has difficulty in use because of its complexity. To overcome these disadvantages, we studied the optimized non-contact capacitive sensors and designed several capacitive sensors for accurate measuring the location of piston in hydraulic cylinder. The proposed capacitive sensor has the possibility of practical use for hydraulic cylinder through experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1207-1212
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• 2011

This paper presents a study on the DSP(Digital Signal Processor) controller for the PBW(power-by-wire) system using BLDC(Brushless Direct Current) servo motor pump. The PBW hydraulic actuator was realized with hydraulic pump driven by BLDC servo motor, hydraulic cylinder and controller. This PBW system needs speed control of servo motor for linear thrust action of hydraulic cylinder. This paper implements a servo controller with vector control algorithm and MIN-MAX PWM technique. As CPU of a controller, TMS320F2812 DSP was adopted because it has PWM waveform generator, A/D converter, SPI(Serial Peripheral Interface) port and many input/output port etc.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.151-160
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• 2008

In this paper, the analysis results of synthetic resonance characteristics are described for the electrohydraulic thrust vector control actuation system. The synthetic resonance is induced by integration of position servo actuation system on the flexible launch vehicle mounting structure. The new resonance mode is synthesized due to composition of hydraulic resonance for electrohydraulic position servo system with inertia load condition and structural resonance for flexible mounting structure. This synthetic resonance can make stability of control system worse by feedback and amplification of control system. The exact nonlinear analysis model of this phenomenon is developed to predict and design a control algorithm for improvement characteristics. The DPF (Dynamic Pressure Feedback) control algorithm has been designed and has excellent resonance suppression capability.

• Transactions of the Korean Society of Mechanical Engineers
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• v.4 no.3
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• pp.96-104
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• 1980

유압이 변화할 때 증기기포의 크기를 구하는 공식을 제시하였다. 이 공식은 변화하는 유압하에서 기포의 크기를 상한과 하한으로 표시한 Hopper, Faucher 및 Eidlitz가 제시한 공식과, Plesset과 Zwick이 해결한 일정유압하에서 성립하는 기포에 관한 간단한 asymptotic 공식을 모두 대체 하기 위한 것이다. 여기에 제시한 새로운 공식의 정확성을 검토하기 위하여 Hooper, Faucher 및 Eidlitz가 보고한 실험결과와 이론적으로 얻은 결과와를 비교하여 보았다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1755-1759
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• 2003

The hydraulic excavator has been a popular research object for automation because of its multi-workings and economic efficiency. The objective of this paper is to design each components and to construct boom, arm, bucket circuit. These models modeled with AMESim show us change of variables and behavior of excavator. Simulation model will be used for simulator of excavator.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.9-10
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• 2006

본 논문은 기존 Reamer Bolt 사용시 발생하는 여러 가지 문제점를 해결하고 고가의 수입품을 대체하기 위한 유압식 커플링 볼트의 국산화를 소개하였다.

• Proceedings of the Korean Reliability Society Conference
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• 2000.11a
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• pp.75-86
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• 2000

본 연구사례는 댐 수문용 대형유압실린더(Piston Diameter :630mm, Stroke:8.3m, weight :30ton, Retraction Force:450ton)의 신뢰성평가를 위한 검토과정에서 제기된 문제를 보완하여, 평가규격을 정립하고, 시험장비를 구축하여, 초대형 유압실린더의 신뢰성 평가를 실시한 사례에 대하여 정리한 것이다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.335-340
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• 1992

유압 시스템(System)은 원동기의 기계적 에너지를 유압펌프가 작동유를 압력 에너지의 형태로변환 시켜 이것을 유합 실린더(Cylinder)등의 엑츄에이터(Actuator)가 다시 기계적 에너지로 변환시켜 부하 를 구동하게한다. 상용차(NT-1, KH 등)용 파워스티어링(Power Steering)에 장착되는 Vane Type Oil Pump (이하 VOP)가 바로 이와같은 역할을 담당하고 있다. 본 연구에서는 VOP의 성능과 관련되어지는 주요 제원(Parameter)인 미끄럼부에서의 틈새, 작동유점도, 압력변화, 회전수 등을 다양하게 변화시키는 모의실험(Simulation)을 통하여각각의 조건하에서얻어지는 누설 유량과 체적효율을 수치적 으로 예측하고 이것을 주요제원을 고려하여 해석해서 정량적인 값을 얻는 것을 목적으로한다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.60-65
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• 2002

최근 신규 공급되고 있는 트랙터와 같은 로외 승용형 차량 및 산업용차량에는 고가의 유압 장치들이 부착되어지고 있다(그림1, 그림2). 이러한 차량들에 장착되어지고 있는 유압장치들은 아직 국내의 기술로는 제품의 정확도 및 신뢰성 등이 문제시되어 대부분이 수입에 의존하는 고가의 장비들이므로 특별한 관리가 요구되어지고 있는 실정이다. (중략)