A sensorless physiological control algorithm for left ventricular assist device for heart failure patients

In order to evaluate ventricular assist devices in heart failure (HF) patients, an optimised lumped parameter model of cardiovascular system (CVS) in conjunction with left ventricle assist devices (LVAD) was used to investigate different control strategies. This paper presents the design of an advanced physiological method for the control of average pump flow in LVADs. The purpose of the proposed control method is to automatically adjust the pump speed to meet for changes in physiological demand. We propose an innovative approach combining a feed-forward and a dynamic sliding mode control (SMC) to determine an appropriate pump flow. Sensor-less measurement of pulse width modulation (PWM) signal is used as inputs to the dynamical model for pump flow estimation previously developed and verified in our laboratory using dogs data. The performance of the proposed control method is tested by carefully examining the immediate response of the controllers to short term of circulatory changes ranging from rest to exercise in CVS - LVAD interactions. Simulation results demonstrate that the developed controller properly tracks the desired reference flow in presence of model uncertainties and external disturbances for LVADs.