A sensorless approach to control of a turbodynamic left ventricular assistsystem

A fuzzy logic controller for a rotary, turbodynamic left ventricular assist system was developed to optimize the delivery of blood flow without induci ng suction in the ventricle, The controller is based on the putsatility in blood flow through the pump and assumes that the natural heart is still abl e to produce some pumping action. To avoid the use of flow transducers, whi ch are not reliable for long term use, the controller estimates flow using a model of the assist device. The controller was tested in computer simulat ion, a mock circulatory system, and in animal experiments. Simulation studi es suggest that the fuzzy logic controller is more robust to parameter chan ges than a traditional proportional-integral (PI) controller. Experimental results in animals showed that the controller is able to provide satisfacto ry flows at adequate perfusion pressures while avoiding suction in the left ventricle.