Modeling and Dynamic Behavior Analysis of a Hydraulic Servo System with Consideration of Pipeline Effect

The long pipeline in hydraulic system has some influence on system performances and even causes the system to become unstable. Aiming at a hydraulic servo system with long pipelines between hydraulic power supply and servovalve, a mathematical model considering pipeline effect was established by means of the theories of transmission line dynamics and hydraulic control systems, in which pipeline characteristics were depicted by lumped-parameter model. The impact on system dynamic behaviors were investigated theoretically, a simulation was carried out in AMESim, and the influences of pipeline structural parameters on hydraulic system dynamic characteristics were analyzed. The results indicate that system response time rises with the pipeline length increasing and the diameter shrinking, but there will be no improvement in performance while the diameter is over a certain value. By analyzing accumulator function for eliminating pipeline effect, it is shown that accumulators configuration at inlets of servovalve and supply and return pipelines can eliminate the adverse effect of pipelines preliminarily, and improve system dynamic qualities.