Browsing by Author "Anteneh, Nebyu"

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    Design of Fuzzy Sliding Mode Controller for Heartbeat Pacemaker Based on ECG Signal Tracking
    (Addis Ababa University, 2020-11) Anteneh, Nebyu; Dereje, Shiferaw (PhD)
    Every year, heart disease is becoming the major cause of death. Therefore, the need arises to find advanced approaches to keep the patients safety. Implantable cardiac pacemakers are an electronic device that can track and boost the heart rate and manage rhythm disorders. This thesis presents nonlinear control of heartbeat model. Because of certain severe cardiac arrhythmias display nonlinear feature which is usually correlated with unpredictable and oscillatory behavior, a nonlinear technique is used to model heart electrical activity. Zeeman’s heartbeat model was used to generate ECG signals. Existing model of heartbeat was analyzed and revised by integrating the control input to add the control mechanisms as a pacemaker. In this study, sliding mode control (SMC) is applied to heartbeat model in order to track and generate real ECG signal. Fuzzy logic algorithm was also used with SMC to reduce chattering happened due to high frequency oscillations around the sliding surface that will shorten the life span of pacemaker. Therefore, a fuzzy sliding mode controller (FSMC) for cardiac pacemaker based on ECG signal reference tracking system was designed. In addition, since the heartbeat pacemaker is disturbed by the brain signal and sensor output delay, the robustness of the system to disturbance, parameter variations and possible time delay on the feedback system were analyzed. The effectiveness of the proposed method was verified through simulation studies using Matlab/ Simulink software. The proposed control law has shown satisfactory performance in terms of tracking ECG signal of the actual data, obtained from the MIT- Boston’s Beth Israel Hospital (BIH), and the physioNet database by eliminating chattering compared with the use of SMC controller. In addition, the result of root mean square error was reduced by 0.00005 % and total harmonic distortion analyzed from FFT window was reduced by 121.35 % when FSMC was applied to the system compared with SMC. The control strategy was also found to be robust with respect to external disturbances, parameter variations and random feedback delay. Therefore, control algorithm will be applied in dual sensor cardiac pacemakers for clinical use.