Development of piezoelectric pump for closed-loop glucose level control

The objective of this thesis is to develop a closed-loop compact, energy-efficient, and valveless piezoelectric actuated micro insulin pump, its simulation model and controller to keep glucose levels in the desired range for T1DM (Type-I Diabetes Mellitus) patients. The pump, designed with a novel approach, is different from the syringe-type pumps/artificial pancreas studies in the literature, including multiple controllers and embedded insulin-glucose models. 3D piezoelectric-structural-fluid coupled finite element analyzes (FEA) of the piezoelectric actuated pump were performed in COMSOL Multiphysics. An integrated simulation environment was created in MATLAB / Simulink environment with the reduced-order (ROM) piezoelectric actuated pump model from the analysis model, the insulin-glucose models of Ackerman, Bergman and Sorensen, the designed proportion integral derivative (PID), the optimal and model predictive control (MPC) controllers. While optimizing the design, different analyzes have been made to have the most efficient pump according to energy requirements and geometric constraints. The nozzle/diffuser divergence angle, nozzle/diffuser diameters, lengths, chamber height, excitation voltage and frequency are optimized for the highest net flow rate and the minimum power consumption. After the parameters determined according to the analyses results were verified analytically, the piezoelectric pump experiment setup was manufactured and assembled. When the pump which was experimented with different voltage and frequency excitation, was actuated with 100Vp-p and 100Hz sine signal, a current consumption of 0.4mA and a flow rate of 300μL / min was obtained. While the requirements of insulin infusion were met from this flow rate, simulation models including three different insulin-glucose models with different patient parameters were run and PID, optimal and MPC controllers were designed. PID parameters were optimized according to Ackerman, Bergman, and Sorensen. The optimal and MPC controllers were designed using Ackerman's model and applied to all insulin-glucose models. While the energy-efficient piezoelectric actuated pump was being developed, an energy harvesting system from a human body that could meet some or all its energy needs was researched, as well. Energy harvesting methods from the human body were investigated. Consequently, one of the harvesting methods, which is piezoelectric energy harvester was selected as an example. 3D piezoelectric-structural coupled FEA studies and experiments were carried out. With a piezoelectric energy harvester placed on the sole of the foot, it has been shown that part of the energy requirement for the system is met by the energy obtained during walking and running. It has been shown that this energy harvesting method which will be obtained from different parts of the body can meet the needs of the whole system in the future.