Abstract:
Automatic controllers for insulin infusion are used in arti cial pancreas for
treatment of diabetes type 1 patients. Controllers are designed based on
some models of blood glucose-insulin system. A physiologically veri ed model
that governs the characteristics of human blood glucose is Bergman's nonlinear
model. Using this model we have designed an adaptive backstepping
based nonlinear controller for diabetes type 1 patients. For controller glucose
e ectiveness factor of blood is treated as an unknown parameter and
numerical values of controller gain and tuning function are selected to produce
best possible results. A complete mathematical derivation of nonlinear
controller is described and simulation results are discussed using MATLAB
SIMULINK. Lyapunov stability theorems are used to analyze stability and
convergence of blood glucose level to a desired concentration. Lyapunov
theorems propose exponential stability of controlled glucose concentration.
Simulation results also indicate faster convergence in tracking response and
overshoot/undershoot characteristics as compared to some recently developed
techniques in literature. In the end a simple backstepping based nonlinear
controller is also proposed. Again its exponential stability is proved
mathematically and shown in simulations also. Comparison of SIMULINK
results with adaptive backstepping based controller is discussed in the last
chapter.
