Desenvolvimento de controladores Fuzzy para o processo de torração do café arábica

Abstract

Roasting is a thermal process in which coffee beans are subjected to the development of aroma, flavor and texture. Some process variables are required to be controlled, such as air and heat flow, roaster temperature, roasting time, among others; being the most important factor the relationship between the. To achieve system control, operators perform remainder comes as a consequence based on their knowledge and experience. An alternative is automatic control, which can be done using electronic and computational resources. In this manuscript, intelligent fuzzy modeling approaches are addressed for temperature control. Based on fuzzy set theory and fuzzy logic. It is widely used in nonlinear process control mainly in situations in which there are no specific methodologies and known differential equations to be considered for the system under study. The objective of the present study is to develop fuzzy systems to control the temperature of the coffee roasting process. The methodology is based on the design of a fuzzy PD and a fuzzy PID controllers according to fuzzy system fundamentals, which are fuzzification, inference to a rule base, and defuzzification. The MATLAB software was used for controller design and preliminary process simulations, the latter being done within the Simulink environment. First, we validate the dynamic of the roasting process by analyzing it in open loop. Then the performance of the fuzzy closed-loop system regarding the transient and stationary responses is analyzed. The results obtained contribute to the study of the coffee roasting process behavior. The results support the importance of fuzzy intelligent control to track the irregular trajectory of desired temperatures. In addition, this study can be considered an initial step for the automation of the Arabica roasting process.