Construcción de un controlador de temperatura basado en lógica difusa aplicado al sistema de enfriamiento del láser de una máquina de corte CNC.

Abstract

The following investigation is about the construction of a water-cooling system for a carbon dioxide (CO₂) laser tube of 100 W with a fuzzy control. First, an analysis was done to identify the physical elements to be part of the system. Once the system was implemented, an experimental method and data processing with Matlab were used to obtain the mathematical model that represents it. Based on the model obtained, a proportional- integral- derivative controller (PID) to maintain the refrigerant of the system in the ideal operational conditions was developed. After that, two controllers were designed using the fuzzy logic. For these controllers, the error and the derivative of error were used as the input, and as an output the percentage of the work cycle in a signal with Pulse Width Modulation (PWM) was used. For both controllers the same fuzzification process was followed. On the other hand, for the inference and defuzzification stage the method Mamdani and Takagi- Sugeno- Kang (TSK) were applied to compare them. The third controller was developed using the fuzzy logic with the inference method TSK to the proportional- integral- derivative controller in the variation of the variable gains proportional and integral. The controllers developed were applied and the cooling system performance was analyzed with every controller in transitory and stationary time. After the assessment, it was determined that performance with the controllers based on the fuzzy logic is better than the performance with the derivative controllers. We came to this conclusion because when the Mamdani and TSK inference methods were applied, no alterations over the limit were observed and the settling temperature time was inferior. On the other hand, with the derivative controllers with variable gains applying the TSK method, the results obtained were better depending on the base of the rules used.