Safety-enhanced optimal control of turbodynamic blood pumps.

A safety-enhanced optimal (SEO) control algorithm for turbodynamic blood pump is proposed. Analysis of in vivo animal experimental data reveals that two new control indices-the gradient of pulsatility of pump pressure head with respect to pump speed and the gradient of minimum pump flow-have their peak within a proximity to the suction point but not at the exact suction point. They were also verified to satisfy the requirement of cost function for the extremum seeking control (ESC). New cost functions were tested for ESC to find and track the new operating point--SEO operating point--where sufficient cardiac perfusion and safety margin to suction is guaranteed. By computer simulation, it is confirmed that the SEO operating point was successfully found and tracked in both fixed and varying hemodynamic load scenarios using proposed control indices without resorting to a slope seeking control algorithm where the reference slope must be supplied.