Tadahiko Shinshi

A magnetically levitated centrifugal blood pump (MedTech Dispo) has been developed for use in a disposable extracorporeal system. The design of the pump is intended to eliminate mechanical contact with the impeller, to facilitate a simple disposable mechanism, and to reduce the blood-heating effects that are caused by motors and magnetic bearings. The bearing rotor attached to the impeller is suspended by a two degrees-of-freedom controlled radial magnetic bearing stator, which is situated outsi

A magnetically levitated (maglev) centrifugal blood pump (CBP), intended for use as a ventricular assist device, needs to be highly durable and reliable for long-term use without any mechanical failure. Furthermore, maglev CBPs should be small enough to be implanted into patients of various size and weight. We have developed a compact maglev CBP employing a two-degree-of-freedom controlled magnetic bearing, with a magnetically suspended impeller directly driven by an internal brushless direct cu

Fast steering mirrors (FSMs) are used to correct images observed by satellites. FSMs need to have large apertures and realize high precision and the positioning of the mirror in the tip-tilt and axial directions needs to be highly precise and highly responsive in order to capture large-scale, high-resolution images. An FSM with a large-diameter mirror supported by a compact magnetic suspension and driven by long-stroke voice coil motors (VCMs) is proposed in this paper. The magnetic suspension a

Centrifugal blood pumps that employ hybrid active/passive magnetic bearings to support noncontact impellers have been developed in order to reduce bearing wear, pump size, the power consumption of the active magnetic bearing, and blood trauma. However, estimates made at the design stage of the vibration of the impeller in the direction of passive suspension during pump operation were inaccurate, because the influence of both the pumping fluid and the rotation of the impeller on the dynamic chara

As the rotational speed of conventional rotor systems supported by oil-film bearings has increased, vibration problems such as oil whip and oil whirl have become apparent. Our group proposed the use of active magnetic bearings (AMBs)/bearingless motors (BELMs) to stabilize these systems. In such a system, measuring the variable stiffness and damping of the oil-film bearings, the current-force and displacement-force parameters of the AMBs/BELMs, and the residual unbalanced force is necessary to s

To enhance the durability and reduce the blood trauma of a conventional blood pump with a cone-shaped impeller, a magnetically levitated (MagLev) technology has been applied to the BioPump BPX-80 (Medtronic Biomedicus, Inc., Minneapolis, MN, USA), whose impeller is supported by a mechanical bearing. The MagLev BioPump (MagLev BP), which we have developed, has a cone-shaped impeller, the same as that used in the BPX-80. The suspension and driving system, which is comprised of two degrees of freed

In the field of extracorporeal circulation, the use of high cost NdFeB magnets (PMs) in the disposable pump head of centrifugal blood pumps (CBP) need be avoided. In this paper, a bearingless slice motor consisting of a solid iron rotor and a reusable part having ring PMs which can be applied to a CBP is introduced. It realizes a cost- effective disposable pump head and a compact reusable part. To eliminate PMs from the disposable rotor, two PM rings and two iron rings are axial-symmetrically ar