LVAD Functional and Transient Response Analysis and Control

Talebian Ardestani, Mohammad Taher | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 46794 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Jahed, Mehran
  7. Abstract:
  8. When heart failure occurred, revascularization to body’s organs and consequently covering the metabolic demands of different sections faces with problem. Chronic heart failure is the first reason of mortality all over the world. Traditional treatment for CHF at end stage is heart transplantation. But some of patients don’t have the opportunity to benefit from heart transplantation because of aging, health conditions and lack of donors. On the other hand, Left Ventricular Assist Devices that are using for supporting a ventricle suffering from failure face with basic chalanges for example, backflow in lower speeds and suction in higher speed. These constrictions necessitate maximum and minimum values for pump speed in every physiological condition. For example, in a proportional controller heart rate had been estimated from base frequency of motor current waveform and had been considered as a linear function of rotational pump desired speed. From another approach it had been considered that adequate perfusion in tissues results when the pump speed is controlled in the way that the difference between the mean pressure of left ventricle and aorta (∆P) stays near a reference value (∆Pr) in every time moments. On the other hand, control of the nonlinear and non-certainty systems without using of mathematical modeling, encouraged lots of researchers using fuzzy logics for controlling the operation of LVADs. Fuzzy logic controllers could provide a systemic method for organizing and combining human mind into controller structure. Also, in optimal controllers predefined penalty functions are tried to be minimized. Multipurpose optimizations are used for satisfying a branch of constrictions like cardiac output and left ventricular pressure. This research, by using of a lumped parameter model of the heart and cardiovascular system attached by an LVAD, try to investigate the online operation behavior of the system that in a challenging topic at controlling point of view. The following a double part control structure designed that the first part is a proportional extermum seeking controller responsible for appropriate revascularization and the second part is a derivative controller that prevent the system from occurring suction
  9. Keywords:
  10. Cardiovascular System ; Controller ; Ventricular Assist Device ; Heart Pump

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