Masters Degrees (Electrical and Electronic Engineering)

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Browsing Masters Degrees (Electrical and Electronic Engineering) by Subject "A closed-loop System"

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    A closed-loop system between intra-ear canal monitoring and general anesthesia
    (Stellenbosch : Stellenbosch University, 2021-03) Setati, Tiro; Perold, Willem; Fourie, Pieter; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: South Africa has a shortage of workers in the healthcare sector, and this short-age extends into anesthesiology as well. With this need, it would be helpfulto introduce a system that administers anesthesia automatically to lighten theload on anesthesiologists as well as to help distribute available anesthesiologistsmore evenly across the South African population. Therefore, a closed-loopcontrol system maintaining a patient’s depth of anesthesia was designed.The system designed consists of an intra-ear electrode and monitor, readingmid-latency auditory evoked potentials (MLAEP) from a patient, a controlsystem and an infusion pump to infuse anesthetic to a patient. The focus ofthis study will be the design of the closed-loop control system interfacing theintra-ear monitoring system and the infusion of anesthetic.The closed-loop control system will have a reference MLAEP latency orplasma concentration that it will need to follow, and the intra-ear monitor willsend the latencies read from the patient. These will be the inputs to the controlsystem’s model predictive controller (MPC), which incorporates a model of thepatient within the controller so that the infusion regime it determines is basedon patient-specific parameters. Once the amount of infusion is determined,the system will send infusion instructions to the infusion pump to administerthe correct amount of anesthetic to the patient.The designed control system was simulated, and its performance was com-pared to a simulated closed-loop control system based on a PID controller.This controller shows overall better control because of the shorter settlingtime, smaller overshoot, and smaller errors between the reference value and the measured output that the MPC control loop achieves. The effect of mea-surement noise on MPC control system was also investigated and the resultsshowed that the system was able to operate adequately with signal-to-noiseratio (SNR) down to 15 dB.From the simulations conducted, it was shown that the closed-loop controlsystem could keep a simulated patient adequately sedated using the MLAEPas an adequate control signal to keep the patient sedated.