Modelling and control of an hydraulic press for the tile industry

To sum up, the objective of the project was to construct a mathematical model that would sufficiently describe the behaviour of the complex hydraulic press system under analysis. Through the Simscape tool inside the Simulink environment, it was possible to select elementary blocks that expressed similar physical behaviour with respect to those corresponding elements comprising the real machine. The second goal of the project was to analyze different control designs, that could be implemented given the control variables at disposal, to minimize the filling error inside the piston chamber. Such error if present could cause instability in the vertical motion of the hydraulic cylinders, as well as deviation of pressure value inside the chamber from the optimal one, requested to achieve good performances in the tile formation process. The current open-loop behaviour has been shown to generate large filling errors during the pressing cycle, and such errors have been drastically reduced up to an order of $10$, by implementing the closed-loop control schemes presented. The first control scheme is based on a feedback measurement coming from an hydraulic volumetric flow rate sensor, and even though it showed good performances relative to the minimization of the filling error, it lacks in practicality, since such sensor is not available in the real setup. Therefore, a closed-loop control scheme based on the pressure measurement feedback, and an hysteresis controller, forcing the pressure signal to remain inside a bandwidth around the optimal value, has produced similar if not better results with respect to the more theoretical approach but with the advantage of practicality.