Dynamic Simulation of a Position-Controlled Electrohydraulic System Using EASY5 1999-01-2855

A servovalve - controlled hydraulic motor - driven positioning system was built. The hydraulic system was modeled and simulated using EASY5 software which had predefined hydraulic components models in addition to the ability of defining new ones. EASY5 model made it possible to study the dynamic behavior of the system under varied conditions of entrained air, motor displacement, motor leakage, and mass changes. Different systems components were tested in order to have the required data needed to build the final model. Pump flow rate, motor leakage, servovalve leakage, and slide table friction were experimentally measured. The slide table dynamic model was proposed and the performance data was measured. Eigenvalue sensitivity analysis showed that fluid line between the hydraulic motor and the servovalve is the most influential factor on system stability.

The results showed that using 0.1in³ displacement motor reduced total time although it increased time delay compared with the 0.15in³ and 0.3in³ displacement Motors. On the other hand using shorter conductor reduced the total time compared with the longer lines. Also, increasing tubing length increased the pressure in motor outlet port.