• 한국정밀공학회지
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• 제25권2호
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• pp.49-56
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• 2008

In order to reduce energy consumption, secondary controlled system has been applied to many types of equipments. In lifting equipments or press machines using hydraulic cylinder, a hydraulic transformer is used as a control component instead of a valve for motion control and a component for recovering potential energy of load. The transformer is a combination of a variable displacement pump/motor as a secondary controlled element and a fixed displacement pump/motor. In this paper the effect of transformer is studied. Multiple closed loop controllers with displacement feedback of variable pump/motor, speed feedback and position feedback of cylinder are used. The efficiency and energy consumption when cylinder is driven up and down is calculated by simulation. Simulation results show that considerable energy saving is achieved by choosing load ratio, circuit type and supply pressure.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.917-922
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• 2008

In order to reduce energy consumption, secondary controlled system has been applied to many types of equipments. In lifting equipments or press machines using hydraulic cylinder, a hydraulic transformer is used as a control component instead of a valve for motion control and a component for recovering potential energy of load. The transformer is combination of a variable displacement pump/motor as a secondary controlled element and a fixed displacement pump/motor. Based on the nominal model derived from mathematical model, the feedback type two-degree-of-freedom controller is designed and implemented. From simulation results, the disturbances including nonlinear friction torque, leakage flow and load force can be compensated and good positioning accuracy is obtained. It show that the proposed controller is effective.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1075-1080
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• 2007

In order to reduce energy consumption, secondary controlled system has been applied to many types of equipments. In lifting equipments or press machines using hydraulic cylinder, a hydraulic transformer is used as a control component instead of a valve for motion control and a component for recovering potential energy of load. The transformer is a combination of a variable displacement pump/motor as a secondary controlled element and a fixed displacement pump/motor. In this paper the effect of transformer is studied. Multiple closed loop controllers with displacement feedback of variable pump/motor, speed feedback and position feedback of cylinder are used. The efficiency and energy consumption when cylinder is driven up and down is calculated by simulation. Simulation results show that considerable energy saving is achieved by choosing load ratio, circuit type and supply pressure.

• 유변학
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• 제11권1호
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• pp.1-8
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• 1999

본 논문은 높은 압력차의 유동모드 하에서의 정상전단거동을 고찰하였다. ER유체 조성에 사용된 비전도성 용매는 10cS의 점도를 갖는 트랜스포머 오일이 사용되었으며, 전도성 입자의 중량비를 20 wt%와 30 wt%로 조절하여 입자 중량비에 대한 영향을 고찰하였다. 두 가지로 조성된 수계 ER유체를 ERF 1과 ERF 2로 칭하였으며, 성능 비교를 위하여 외국의 우수하다고 알려진 비수계 ER유체인 ERF 3를 사용한 실험도 실시하였다. 높은 압력차의 유동모드를 발생시키기 위해, 양방향 유압 실린더를 이용하여 고압의 질소 가스로 작동되는 실험 장치를 자체 제작하였다. 전극 앞에 장착된 압력 센서를 통해 전극 양단의 압력차를 구하고, 실린더 로드에 부착된 변위센서로부터 측정한 피스톤 속도를 유량 계산의 기초 자료로 사용하였다. 유동모드에 대한 유체역학적 해석을 통해 유도된 수식을 인용했으며, 위의 기초 자료와 수식을 이용하여 유동모드형 응용 장치에 적용하기 위한 전단변형률에 대한 전단응력의 결과를 도출하였다.