• Journal of Biosystems Engineering
• /
• 제21권2호
• /
• pp.155-166
• /
• 1996

A direct injection sprayer was designed using the concepts of injection mixing and total flow control, flowrate-based system compensating for the variation of forwarding speed. A metered rate, proportionally to the actual diluent flow rate, of a tracer chemical was injected directly into the diluent stream. The injection of chemical may improve the precision and safety of chemical application process. The control system was evaluated for the variables of the control interval, tolerances and sensitivities of flow regulation valve and injection pump. Performance of the system was assessed as that the response time of flow rate, response time of injection rate, absolute steady state error, and the coefficient of variance(C.V.) of concentration were 8.5 and -0.53 seconds, 0.067 lpm(0.8%) and 3.15%, respectively, at optimal parameters of control interval of 1.0 sec, fast sensitivity of flow regulation valve, medium sensitivity of injection pump and medium tolerance of flow rate. Performance of the system can be improved by increasing the sensitivity of flow regulating valve and employing a high resolution velocimeter, such as Doppler radar.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1996년도 추계학술대회 논문집
• /
• pp.913-920
• /
• 1996

In this study, the counting method for multi-axial and multi-point load states was proposed. Using this counting method, the load spectrum is generated from the service load history which is measured for boom structure of excavator. Loading state for loading points of boom structure is described as a multi-dimensional state space. From this load spectrum, the stress spectrum was generated by FEM analysis using the superposition of the unit load. The cumulated damage at the severe damage point of In nm structure by the failure example is calculated by Palmgren-Miner's rule. As a result of this study, the fatigue life estimation using the multi-axial and multi-point load counting method is useful.

• 한국전자파학회논문지
• /
• 제10권3호
• /
• pp.329-339
• /
• 1999

LPDA(Log-Periodic X Dipole Antenna)에 비하여 안테나 붐의 길이가 짧으면 서도 복사특성이 우수한 대수주기 안테나로서 X 다이폴을 구성소자로 하는 LPXDA(Log-Periodic X Antennas)를 제안하였다. 500MHz~1,000MHz에서 동작하는 LPXDA를 설계하고 모멘트법을 이용하여 설계안테나의 본사특성을 해석하여 LPDA의 특성과 비교 검토하였다. 그 결과 본 논문에서 제시한 LPXDA가 LPDA보다 붐의 길이가 20%짧으면서도 주파수 변화에 따른 복사특성이 우수한 것으로 나타났으며 LPXDA의 측정결과도 계산결과에 근접하는 것으로 나타났다.

• 유공압시스템학회논문집
• /
• 제6권4호
• /
• pp.1-8
• /
• 2009

Nowadays with the high fuel prices, the demands for energy saving and green emission of construction machinery have highly been increased without sacrifice of working performance, safety and reliability. The aim of this paper is to propose a new energy saving hybrid excavator system using an electro-hydraulic actuator driven by an electric motor/generator for the regeneration of potential energy. A 5 ton class excavator is analyzed, developed with the boom for the evaluation of the designed system. The hardware implementation is also presented in this paper. A control strategy for the hybrid excavator is proposed to operate the machine with a highest efficiency. The energy saving ability of the proposed excavator is clearly verified through simulation and experimental results in comparison with a conventional hydraulic excavator.

• 드라이브 ㆍ 컨트롤
• /
• 제14권3호
• /
• pp.1-7
• /
• 2017

Energy consumption of conventional hydraulic excavators controlled by MCV is considerable when negative load is applied because the meter orifice and meter-out orifice are machined in one spool. Therefore, IMV is introduced to save energy use of hydraulic excavators, but existing hydraulic excavators have various advantages so it is difficult to make a clear comparison. In this study, we compare the use of an existing MCV excavator that has many advantages such as negative control, and IMV for boom up and down operation, and if IMV is used to save energy, we will examine the cause. If possible, for comparability under the same conditions, both systems use pressure balance valves to minimize power consumption when not using power in the actuator. The orifice area at each notch of each valve is calculated, and energy saving is verified by comparing the two systems through simulation.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.870-874
• /
• 2004

This paper presents a three dimensional modeling and simulations of operation and running of a wheel loader using the ADAMS program. A wheel loader consists of a bucket, a boom, a crank, a front frame, a rear frame, a bucket cylinder, two boom cylinders, two steering cylinders, nine spherical joints, six universal joints, five translation joints, three inline joints, a revolute and a fixed joint. Judging from the actual degrees of freedom of the wheel loader, proper kinematic joints are selected to exclude redundant constraints in the modeling. Through the running simulation over a bump with the three dimensional modeling, the joint reaction forces are calculated.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2002년도 추계학술대회 논문집
• /
• pp.481-486
• /
• 2002

Automation of Field Robot has many advantages for efficiency and convenience. In this paper, mathematical equation of field robot is established and automation system is constructed. Hydraulic and Dynamic equation of field robot are constructed in this paper. Inputs of system are angle data from each link (boom, arm, bucket, swing) and pressure data from in, out port of each cylinder. Outputs of system are voltage into electo-proportional valve.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2002년도 추계학술대회 논문집
• /
• pp.75-79
• /
• 2002

A hydraulic Excavator is applied for outdoor tasks in construction, agriculture and undersea etc. When a hydraulic Excavator works crane function tasks, most of disasters happen. In this study, In order to preventing these disasters, the safety equipment algorithm for crane working is developed, and the safety equipment algorithm for crane working is being developed. The proposed control algorithm(Zero Moment Point) is designed to avoid overload. The hydraulic excavator for crane function must work within a maximum limit of load. To accurately detect a working load, pressure sensors of boom, arm cylinder, and angle sensors of boom, arm and bucket joint are used.

• 대한기계학회논문집A
• /
• 제25권7호
• /
• pp.1097-1106
• /
• 2001

A telescopic handless is a kind of construction machinery for loading, carrying and unloading various cargos. A residual vibration of the boom, however, is often caused in carrying cargos to high workplace, especially in small motion and unloading operations, even when an expert of this machine handless the boom. To solve this vibrational problem, we applied TDC and newly proposed Commandless IST to the telescopic handler, and confirmed their effectiveness through experiments. These promising results show that the proposed control schemes can improve productivity, safety and ride comfort of the telescopic handler.

• 한국해양공학회지
• /
• 제19권1호
• /
• pp.71-76
• /
• 2005

This paper describes basic structural design for the large floating crane barge of fixed undulation type. Structural analysis was performed separately after dividing the floating crane into two parts, The crane part was composed of jib boom, back stay and back tower and the barge part supported the crane part. The structural strength for jib boom structural members are in compliance with JIS B 8821 and scantling of all barge structural members are in compliance with the requirement of KR (Korean Register of Shipping) Steel Barges and Rules for Classification of Steel Ships. For the structural analysis of large floating crane, MSC/NASTRAN and MSC/PATRAN software were used.