• Title/Summary/Keyword: construction control

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Trajectory Control of Excavator Actuators Using IMV (IMV를 이용한 굴착기 작업장치 궤적제어)

  • Jung, Gyuhong
    • Journal of Drive and Control
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    • v.17 no.2
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    • pp.45-54
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    • 2020

  • The IMV is a combination of four two-way valve systems which replace a conventional four-way spool valve to improve efficiency mostly in excavator hydraulics. As the environmental regulations for construction equipment have tightened, some overseas advanced companies have released commercial excavators in which the MCV is implemented with the IMVs. Development of the IMV type MCV relies on the control algorithm as well as the robust performance of proportional flow control valves. In this study, the IMV controller was designed and verified with experiments for the excavator working unit, which determines the IMV mode of operation and the extent of the valve opening in consideration of the load conditions on hydraulic actuators. First, the open-loop controller was designed with a joystick command vs. a PSV reference current map comprising several control parameters in to compensate for the different flow characteristics and non-linearities of two-way flow control valves. Second, the closed-loop controller was designed with the PI control fed by the actuator displacement and outputs actuator percent effort equivalent to the operator's joystick command. Finally, the performance of the IMV type MCV was verified with the trajectory control of position references derived from the energy consumption test standard. Experimental results showed the control performance of the IMV developed in this study, and suggest that future studies to be conducted to advance technical progress.

  • https://doi.org/10.7839/ksfc.2020.17.2.045 인용 PDF KSCI

Development of Construction Cost Model through the Analysis of Critical Work Items (코스트 중요항목 분석을 통한 공사비 예측모델 연구)

  • Lee Yoo-Seob
    • Korean Journal of Construction Engineering and Management
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    • v.4 no.4 s.16
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    • pp.212-219
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    • 2003

  • In construction project planning and control, a cost model performs a critical role such as cost determination on a contract stage and cost tracing. The model can maximize owner's profit and value within the project budget and optimize cost management works on overall construction implementation stages. A BoQ(Bill of Quantities) generally adopted in a unit price contract has been applied as an important tool for cost control and forecast. However a previous cost model based on the BoQ has shown limitations in that it requires too detailed information and heavy manpower on cost management and difficulty in keeping relationship with construction planning, scheduling and progress management. The each cost items and unit prices which constitute of construction works are individually very important management factors but the relative weight for each items and prices have a difference on the contents and conditions of each conditions of each construction works. In consideration of this structural mechanism of cost determination, this research is aimed at examining the critical factors affecting the construction cost determination and propose and verify a new cost forecasting model which is more simple and efficient and also keeps the accuracy of cost management.

  • PDF KSCI