Speed control of the Implantable Centrifugal Blood Pump to avoid aortic valve stenosis: Simulation and implementation

Abstract

This paper presents a computational simulation and implementation of electromechanical actuator performance of the Implantable Centrifugal Blood Pump (ICBP) as part of a speed controller study to avoid aortic valve stenosis. The ICBP as Left Ventricular Assist Device (LVAD) is an electromechanical device designed for long-term assist left heart in performing its functions. The centrifugal pumps are controlled by varying the rotor (impeller) speed. ICBP successful operation depends on an appropriate rotational speed control system, ensuring: 1) no reverse flow through the pump during left ventricle diastolic phase, and 2) aortic valve correct opening, avoiding later valve stenosis. A computational model of the actuator done in Matlab / Simulink (R2010b, Mathworks, Massachusetts, USA) was used in the simulations. Control and signal processing was used Labview (National Instruments, Austin, USA). Signals equivalent to intraventricular pressure and a variable rotational reference were used to evaluate motor and speed controller performance. Speed values were chosen so that pressure pump exceeds intraventricular pressure only after the opening of aortic valve. The proposed controller is Proportional-Integral (PI) type. The simulation results were satisfactory, no steady error in response speed. Practical tests showed satisfactory results to follow speed reference signal, as simulated. Future studies will evaluate the bands control.