Servo valve-line hydraulic system

Abstract

The objective of this project is to analyze the effects of electrohydraulic system due to hydraulic parametric variation by using control theory and mathematical modelling technique. The electrohydraulic system in this project consists of hydraulic pump, pipeline, servovalve, accumulator and variable orifice.

There are 5 different cases of hydraulic systems to be analyzed using lumped parameter analysis approach. The response of the hydraulic system subjected to step input and different variation of physical parameters, such as the length of pipeline and the load on variable orifice, was performed and studied.

By using Matlab simulation, step response analysis, root locus analysis, Bode diagram, and Nyquist plot were applied to the system. Lastly, recommendation for response improvement was carried out by adding a designed controller to the hydraulic system. In this project, SISO design tool is successfully applied to improve the response.

Based on the results, it is found that the system’s stability is highly related the length of the pipeline. Load on variable orifice which is caused by varying the diameter of orifice, and is found to contribute little effect on the response’s stability. Meanwhile, during the supply breakout, accumulator is proven to maintain good stability of the system by absorbing the pressure shock and vibration efficiently.