• 동력기계공학회지
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• 제6권2호
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• pp.82-87
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• 2002

For the dynamic behavior evaluation of a semi-active vibration control system, it is very important to use an accurate mathematical model for the hydraulic damper applied to the control system. In this study, a mathematical model for a symmetric type hydraulic damper was suggested. In this model, the effects of gas volume and oil temperature variation on the bulk modulus of oil were considered. The dynamic behavior of the damper was investigated by experiments and simulations. It was confirmed that the pressure variation, damping force, and mean pressure variation could be estimated with comparatively good precision by the suggested mathematical model. Moreover, it was shown that excessive pressure rise can be generated by the oil expansion due to the heat energy transformed from the exciting energy of the damper for a short period of the damper operation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1991년도 춘계학술대회 논문집
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• pp.214-224
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• 1991

The porpose in this study is to simulate te force required in the measurement of the performance of the equipments or testipieces. For the simulation of the required force, the difference in eachchamber pressure in the hydraulic cylinder was controlled with Variable Structure Control (VSC) theory. Also, nonlinear Variable Structure Observer (VSO) was designed to estimate the derivative of the load pressure which is necessary to determine the sliding surface in VSC theory. In this paper, the digital computer simulation and experiments were executed.