Abstract-The axial flow maglev blood pump (AFMBP) has become a global research focus and emphasis for artificial ventricular assist device, which has no mechanical contact, mechanical friction, compact structure and light weight, can effectively solve thrombus and hemolysis. Magnetic suspension and impeller is two of the important parts in the axial flow maglev blood pump, and their structure largely determines the blood pump performance. The research adopts electromagnetic and fluid finite element analysis, and puts forward a method to design the magnetic suspension and impeller of axial flow blood pump, which tacks into account the small volume of axial blood pump. The magnetic bearing's characteristics are evaluated by electromagnetic finite element analysis. The Blades have been designed by calculating aerofoil bone line, and make simulation analysis for different thicken ways of blade by Fluent software, and make a conclusion that the blade thickened with certain rules has better characteristics in the same conditions. The results will provide some guidance for design of axial flow maglev blood pump, and establish theoretical basis for application of the implantable artificial heart pump.
Recently, magnetic bearings have been applied to many rotating machines such as turbo-molecular pumps, cooling gas compressor, flywheel energy storage systems. And high-power density is the future development trend of these machines, which demands that the rotor characterizes slender and high rotating speed and operates above the critical speeds. However, it is a big challenge for a flexible rotor to pass the bending critical speeds and operate above the critical speeds steadily and reliably. Based on above reasons, this article presented the design, modeling, and analysis framework of a flexible rotor test rig with active magnetic bearing (AMB). Special attention was paid to the flexible rotor dynamic model development, dynamic analysis, and model-based robust control design. First, the main structure features were illustrated in detail, including the key dimensions and parameters of the AMB components and rotor. Then models of components including power amplifier and displacement sensor were developed. The finite element method based on Timoshenko beam theory was applied to the rotor dynamics model. The dynamic analysis of the rotor is the foundation of the controller design. Hence, modal analysis had been done, obtaining rotor dynamic properties via synthesis of natural frequency, mode shapes, and Campbell plots. Reduced order model was obtained for controller design convenience. A robust H N controller was designed based on the system model and controller performance was validated with numerical simulation. The results indicate that the controller has good vibration suppression performance and makes the flexible rotor pass the first bending critical speed.
Semi-active isolation systems fill the gap between passive and active systems, delivering the versatility and adaptability of fully active systems, by expending a small amount of energy to change system parameters such as stiffness and damping. Magnetic suspension vibration isolation provides an excellent active isolation technology, and has shown useful characteristics including noncontact isolation, fast response, high reliability and long lifespan. However, because it is highly nonlinear and time variant, the control of magnetic suspension vibration isolation is an area that still requires further exploration. This paper presents a fuzzy control algorithm for a semi-active multi-degree-of-freedom vibration system. The fuzzy control is based on the minimization of the weighted sum of squared output forces. The output force response of the fuzzy, PID control semi-active vibration isolation system and passive system under the same excitation are simulated. The simulation results show that the fuzzy control system has much better performance in vibration isolation. An experimental platform is developed to test the performance of the magnetic suspension vibration isolation system and the proposed fuzzy control algorithm. The experimental results are found to be in good agreement with simulation.
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