MAMDANI-TYPE FUZZY CONTROLLER TO DETERMINE BLOOD PRESSURE LEVELS BY REFLECTION PPG

This document presents the design of a fuzzy control system applying photoplethysmography techniques to generate input data and Mamdani-type fuzzy logic for its processing and generation of system output values, through which blood pressure levels can be indicated based on the parameters recommended by the medical area for an adult person. The integral design of the system includes the acquisition of the input signals, obtained through the reflection photoplethysmography technique, by means the optical coupling between IR light-emitting diodes and photo receptors, which allow the flow of current proportional to the amount of reflected light by blood, which is related to the flow level of the cardiac cavities, derived from the systolic and diastolic stages of the cardiac cycle. The fuzzy control was designed with two inputs and one output of 5 triangular membership functions each using the hardware description language (VHDL), the fuzzification, inference, aggregation and defuzzification stages were designed using the COSAA method. The response values ​​obtained using the Test Bench tool of ISE Design suite were compared with theoretical values ​​and with values ​​obtained with the Fuzzy Logic Designer tool of Matlab, the results showed an excellent approximation.