Position control of a valve controlled asymmetric cylinder system with time delay

Existence of the long pipeline in hydraulic system will worsen the system dynamic performance. Aiming to acquire a simple control system model, a mass-damping dynamic model was used to simulate pipeline element by analyzing kinetic feature and physical properties of fluid in pipeline, and pipeline transfer function was derived. Mathematic model of position control of valve controlled asymmetric cylinder was established, and the high order plant was disposed to be second-order model with time delay in frequency domain. A PI-PD-Smith predictor was designed, and the parameters of controller were optimized according to integral time absolute error (ITAE) optimization criterion. The system with PI-PD-Smith predictor and conventional Smith predictor was compared by simulation. The result shows that PI-PD-Smith predictor has better control quality than conventional Smith predictor for position control of electro-hydraulic servo system with long pipelines.