Hydraulic Cylinders-Response in Fluid Power Control Systems

Fluid Power Control Systems are mostly used in power plants. System design may change according to the required application and specified output quality. Mathematical model is important to get accurate expectation for system performance. Static and dynamic response of a fluid power control system under different operating conditions, considering supply pressure and temperature variation has been investigated. Different system designs implementing different system stiffness and different types of control valves have been constructed in a linear displacement control system, then experimented and evaluated. Sequence and time of operations has been controlled using PLC controller. Conclusions reveal that the power consumed could be decreased by simplifying system design using one high-response valve instead of two low-response valves. In addition, system dynamics could be improved from 50 % up to 79 % depending on working conditions. Mathematical model for the control system has been predicted, descending from the linear theoretical relationship between flow rate and valve opening according to Bernoulli equation. Supply pressure variation and flow force effects have been considered. The predicted relationship achieved remarkable agreement with the experimental performance of the system.