Modelagem e otimização de protótipo de controlador fuzzy de temperatura para cultivo de microalgas em fotobiorreator para biodiesel

Abstract

This project modeled and optimized a prototype of a fuzzy temperature controller for use in microalgae cultivation in a photobioreactor, employing Simulated Annealing for controller tuning and optimization of the fuzzy defuzzification equations. The prototype consisted of a thermal bath with two temperature sensors, a vessel with electric heating, a cooling water vessel, a water pump, a solenoid valve, and the use of an open-source prototyping platform in C++ (Arduino), LabVIEW for thermal control supervision, and MATLAB for system modeling and optimization. The fuzzy controller was developed using temperature membership functions: Very Low, Low, Optimal, High, and Very High. These parameters were incorporated into the manipulation of electrical heating power, associated with adjustable constants, so that the optimizer could tune the controller to maintain the photobioreactor temperature as close as possible to the desired value. For cooling, the membership functions were also incorporated into the manipulation of the cold-water valve opening, along with other constants. To optimize the constants used in the fuzzy logic, the system developed experimentally was modeled in MATLAB using an energy balance and the Simulated Annealing optimization method. As a result, it was possible to determine the best parameters for the defuzzification equations of this system for application in the temperature controller prototype.