Magnetically Suspended Rotary Blood Pump (Keynote)

2005 ◽  
Author(s):  
Hooshang Heshmat ◽  
James F. Walton ◽  
Michael J. Tomaszewski ◽  
Said Jahanmir
Keyword(s):  
High Reliability ◽  
Medical Center ◽  
Magnetic Bearing ◽  
Operating Conditions ◽  
Active Magnetic Bearing ◽  
Blood Pump ◽  
Rotary Blood Pump ◽  
Centrifugal Blood Pump ◽  
Pump Rotor ◽  
Blood Flows

MiTiHeart™ LVAD is a rotary centrifugal blood pump with a hybrid passive/active magnetic bearing support system. It exhibits low power loss, low vibration, and high reliability under transient operating conditions. Unique features of the design include a simple and direct flow path for both main and washing blood flows, non-contact pump rotor, i.e., no rubbing surfaces, and relatively large clearances between the pump rotor and housing. The first prototype was constructed from medical grade polycarbonate. To reduce the possibility of thrombosis, the internally exposed surfaces were coated with a biocompatible polymer. Hemolysis test results showed a low normalized index of hemolysis of 0.01 mg/dL. An acute animal test was successfully completed at the Hershey Medical Center. During the test, the pump was implanted in a calf and operated in parallel with the heart. Following the acute test a chronic 200-hour implant study was completed. A second prototype was constructed using a titanium alloy for all blood contacting surfaces and incorporating a redundant hydrodynamic thrust bearing. This prototype was successfully evaluated in two chronic implant studies in a calf animal model for a total of 130 hours.

Hybrid Magnetic Bearings for a Centrifugal Blood Pump

2007 ◽  
Author(s):  
Zhaohui Ren ◽  
Said Jahanmir ◽  
Hooshang Heshmat ◽  
James Walton
Keyword(s):  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Force Balance ◽  
Blood Pump ◽  
Axial Position ◽  
Circulatory Support ◽  
Radial Clearance ◽  
Axial Stiffness ◽  
Element Analysis ◽  
Centrifugal Blood Pump

A hybrid passive/active magnetic bearing system was designed for a rotary centrifugal blood pump being developed for long-term circulatory support for heart failure patients. This system consists of two axially spaced bearing combinations for complete magnetic levitation of the rotor using only a single-axis active control. Each bearing combination comprises a pair of axially oppositely polarized permanent magnet rings on the rotor and a similar pair in the stator housing for both radial support and axial bias flux, and an electromagnetic coil to actively control the rotor axial position. The design permits a relatively large radial clearance between rotor and stator, and provides sufficient radial/axial stiffness, active controllability over the desired axial travel of the rotor. The bearing characteristics were evaluated by electromagnetic finite element analysis. The prototype pump was fabricated and levitated using a PID controller with zero-force balance algorithm to stabilize the rotor in the thrust direction and minimize the power draw. The experimental results confirmed the efficacy of the proposed magnetic bearing design and associated control algorithm.

Some Nonlinear Effects of Magnetic Bearings

1999 ◽  
Author(s):  
Norbert Steinschaden ◽  
Helmut Springer
Keyword(s):  
Equations Of Motion ◽  
Period Doubling ◽  
Path Following ◽  
Nonlinear Effects ◽  
Magnetic Bearing ◽  
Operating Conditions ◽  
Active Magnetic Bearing ◽  
Nonlinear Phenomena ◽  
Amb System ◽  
Large Rotor

Abstract In order to get a better understanding of the dynamics of active magnetic bearing (AMB) systems under extreme operating conditions a simple, nonlinear model for a radial AMB system is investigated. Instead of the common way of linearizing the magnetic forces at the center position of the rotor with respect to rotor displacement and coil current, the fully nonlinear force to displacement and the force to current characteristics are used. The AMB system is excited by unbalance forces of the rotor. Especially for the case of large rotor eccentricities, causing large rotor displacements, the behaviour of the system is discussed. A path-following analysis of the equations of motion shows that for some combinations of parameters well-known nonlinear phenomena may occur, as, for example, symmetry breaking, period doubling and even regions of global instability can be observed.

scholarly journals 3D Printing of Functional Assemblies with Integrated Polymer-Bonded Magnets Demonstrated with a Prototype of a Rotary Blood Pump

2018 ◽  
Vol 8 (8) ◽  
pp. 1275 ◽  
Author(s):  
Kai von Petersdorff-Campen ◽  
Yannick Hauswirth ◽  
Julia Carpenter ◽  
Andreas Hagmann ◽  
Stefan Boës ◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Permanent Magnets ◽  
Low Cost ◽  
Magnetic Bearing ◽  
Blood Pump ◽  
Rotary Blood Pump ◽  
Pump Impeller ◽  
Fused Deposition ◽  
Magnetic Components ◽  
Deposition Modeling

Conventional magnet manufacturing is a significant bottleneck in the development processes of products that use magnets, because every design adaption requires production steps with long lead times. Additive manufacturing of magnetic components delivers the opportunity to shift to agile and test-driven development in early prototyping stages, as well as new possibilities for complex designs. In an effort to simplify integration of magnetic components, the current work presents a method to directly print polymer-bonded hard magnets of arbitrary shape into thermoplastic parts by fused deposition modeling. This method was applied to an early prototype design of a rotary blood pump with magnetic bearing and magnetic drive coupling. Thermoplastics were compounded with 56 vol.% isotropic NdFeB powder to manufacture printable filament. With a powder loading of 56 vol.%, remanences of 350 mT and adequate mechanical flexibility for robust processability were achieved. This compound allowed us to print a prototype of a turbodynamic pump with integrated magnets in the impeller and housing in one piece on a low-cost, end-user 3D printer. Then, the magnetic components in the printed pump were fully magnetized in a pulsed Bitter coil. The pump impeller is driven by magnetic coupling to non-printed permanent magnets rotated by a brushless DC motor, resulting in a flow rate of 3 L/min at 1000 rpm. For the first time, an application of combined multi-material and magnet printing by fused deposition modeling was shown. The presented process significantly simplifies the prototyping of products that use magnets, such as rotary blood pumps, and opens the door for more complex and innovative designs. It will also help postpone the shift to conventional manufacturing methods to later phases of the development process.

scholarly journals Nonlinear Control of an Active Magnetic Bearing System Achieved Using a Fuzzy Control with Radial Basis Function Neural Network

2014 ◽  
Vol 2014 ◽  
pp. 1-18 ◽  
Author(s):  
Seng-Chi Chen ◽  
Van-Sum Nguyen ◽  
Dinh-Kha Le ◽  
Nguyen Thi Hoai Nam
Keyword(s):  
Neural Network ◽  
Radial Basis Function ◽  
Basis Function ◽  
Fuzzy Logic Controller ◽  
Magnetic Bearing ◽  
Operating Conditions ◽  
Active Magnetic Bearing ◽  
Highly Nonlinear ◽  
Radial Basis ◽  
Amb System

Studies on active magnetic bearing (AMB) systems are increasing in popularity and practical applications. Magnetic bearings cause less noise, friction, and vibration than the conventional mechanical bearings; however, the control of AMB systems requires further investigation. The magnetic force has a highly nonlinear relation to the control current and the air gap. This paper proposes an intelligent control method for positioning an AMB system that uses a neural fuzzy controller (NFC). The mathematical model of an AMB system comprises identification followed by collection of information from this system. A fuzzy logic controller (FLC), the parameters of which are adjusted using a radial basis function neural network (RBFNN), is applied to the unbalanced vibration in an AMB system. The AMB system exhibited a satisfactory control performance, with low overshoot, and produced improved transient and steady-state responses under various operating conditions. The NFC has been verified on a prototype AMB system. The proposed controller can be feasibly applied to AMB systems exposed to various external disturbances; demonstrating the effectiveness of the NFC with self-learning and self-improving capacities is proven.

20315 Development of a Disposable Extracorporeal Centrifugal Blood Pump with Magnetic Bearing System

2009 ◽  
Vol 2009.15 (0) ◽  
pp. 213-214
Author(s):  
Wataru Hijikata ◽  
Pai Chi Nan ◽  
Tadahiko Shinshi ◽  
Akira Shimokohbe ◽  
Takeshi Someya ◽  
...  
Keyword(s):  
Magnetic Bearing ◽  
Blood Pump ◽  
Centrifugal Blood Pump ◽  
Bearing System

P-MB-05 A PM-EM TYPE MAGNETIC BEARING SYSTEM FOR A CENTRIFUGAL BLOOD PUMP

2003 ◽  
Vol 2003 (0) ◽  
pp. 377-378
Author(s):  
Tadahiko SHINSHI ◽  
Daisaku NISHINAKA ◽  
Junichi ASAMA ◽  
Hiroyuki KATAOKA ◽  
Setsuo TAKATANI ◽  
...  
Keyword(s):  
Magnetic Bearing ◽  
Blood Pump ◽  
Centrifugal Blood Pump ◽  
Bearing System

Design and Implementation of Redundant Sensors in Active Magnetic Bearing

2017 ◽  
Author(s):  
Zhengang Shi ◽  
Jiaji Yang ◽  
Ni Mo ◽  
Xingnan Liu ◽  
Yan Zhou
Keyword(s):  
High Reliability ◽  
Short Circuit ◽  
Stability Control ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Displacement Sensor ◽  
Special Equipment ◽  
Design And Implementation ◽  
Displacement Sensors ◽  
Redundancy Design

With the advantages of frictionless, no need of lubrication, no pollution, low consuming and long life, active magnetic bearing (AMB) is applied in the primary helium circulator of the High Temperature Gas-Cooled Reactor-Pebble bed Module (HTR-PM), which is under construction in Shidao Bay Nuclear Power Plant. Active magnetic bearing is a typical mechatronic system with interconnection of mechanical and electronic components with the function of picking up signals, processing and producing. Displacement sensor is an important component to pick up signals for stability control, and also the most susceptible part to fail due to variation of air temperature and vibration of high rotation speed. However, rotating system can’t run normally if a single sensor fails in AMB without redundancy design. For security considerations, higher reliability is required in some special equipment, especially in primary helium circulator of HTR-PM. Design and implementation of redundant sensors is an effective method. This paper reviewed the present research of fault diagnosis and redundant control of displacement sensors, simulation of coil’s short-circuit and open-circuit fault was made with MATLAB/SIMULINK. Parameters were optimized for fault diagnostic circuit by Multisim. Based on the high reliability demand, redundancy design was applied both on structure and control system in AMB. Schematic drawing and PCB board were finished by Altium Design, and experiments were carried out. The result showed that if the coils of sensor failed, AMB system could still work normally by switching to the redundant sensors automatically.

Sign in / Sign up

Export Citation Format

Share Document