This paper presents the modelling and simulation of a hydraulic positioning system using Matlab/Simulink, including components such as the actuator, pressure relief valve, pipes, and proportional directional control valve. The system was analysed under various operating conditions to predict its behaviour. The proportional valve’s simulation was divided into static and dynamic parts. Manufacturer data for flow, pressure, and leakage were used to develop pseudo-section functions, representing the relationship between spool position and flow rate. A non-linear Simulink model was optimized using the Nelder-Mead simplex algorithm (NFR) and fitted to non-linear frequency response data. Multiple simulations validated the model, with results closely matching the manufacturer’s data. The valve model demonstrated a good positioning accuracy, with minor oscillations at 10% and 25%, and the 100% amplitude curve aligning closely with the manufacturer’s data, confirming the robustness of the simulation.