Thermal vacuum chamber control optimization

Abstract

In a laboratory of the Aerospace Engineering department of the Polytechnic University of Milano (Italy) there is a thermal vacuum chamber. The objective of this type of machines is to test space components. The machine is being improved by student’s projects. This thesis has the objective of including optimal control capabilities for machine’s operation. The typical way of working of the thermal vacuum chamber is the following. An object is put inside the chamber. Then, the chamber is sealed and all air is realised. From this point, the object could be cooled or heated. The heat process is controlled by a PID controller while the cooling is controlled by an on-off control. For this reason, the study of chamber’s heating and cooling is completely different. How the heat has more flexibility to be optimized, this project has the aim of studying a possible change of the PID controller for a new microcontroller that would improve the performances of the system in terms of energy consumption. The idea is to design a smoother and more stable working method that reduces the electricity consumption. Furthermore, with the nowadays microcontrollers calculus power, it is possible to design an algorithm that changes its parameters according to machine’s working conditions. That is to say that, when the Chamber starts the process, are analysed its performances and are chosen the best parameters to work in that moment. Remember that the Chamber heating performances will change every time because of the thermal characteristics of the object that is inside. To carry out the study it has been used the theory of control of physical machines by output prediction with difference equations systems. This mathematical theory is based on the fact that, for any physical system, it is possible to predict its response (output) to any stimulation (input). All software and graphics used in this thesis has been written using the numerical computing environment MATLAB. The future code to be compiled in the microcontroller will be a compilation of the codes used in this work.