| Project/Area Number |
59870046
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
Thoracic surgery
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| Research Institution | National Cardiovascular Center |
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Principal Investigator |
HAYASHI Kozaburo National Cardiovascular Center, Department Director, その他, 研究員 (90026196)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Takao National Cardiovascular Center, Research Associate, 研究所生体工学部, 室員 (00142654)
SEKI Junji National Cardiovascular Center, Research Associate, 研究所生体工学部, 室員 (20163082)
UMEZU Mitsuo National Cardiovascular Center, Laboratory Head, 研究所人工臓器部, 室長 (90132927)
TAKANO Hisateru National Cardiovascular Center, Department Director, 研究所人工臓器部, 部長 (60028595)
AKUTSU Tetsuzo National Cardiovascular Center, Vice Director of Research Institute, 研究所, 副所長 (40150221)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥8,300,000 (Direct Cost: ¥8,300,000)
Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1985: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1984: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Keywords | Cardiac assist device / Artificial Heart / Motor / Pusher-plate / Pulse width modulation (PWM) / Microprocessor / ソフトウェア / ハードウェア |
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| Research Abstract |
A pulse width modulation (PWM) algorithm with fixed duty ratio and variable voltage has been developed to drive and control the implantable electro-mechanical actuator for blood pumps. The actuator incorporated with a dc brushless motor was attached to a pusher-plate-type blood pump. Rotation of the motor is converted into a linear motion by a ball screw. The position of the pusher-pate was monitored with a Hall-effect sensor mounted on the back plate and a magnet attached to the plate. Any other monitors are not necessary for the open-loop operation of the pump. The size of the actuator is 50 mm OD and 30 mm length, and the weight is 480 g. Eight-bit and sixteen-bit microprocessor-based systems were used to drive the motor and to control the whole system, respectively.
The torque performance of the motor assembled in the actuator was studied in detail for the development of the software which controls the speed and the input voltage of the motor without any feed back informations. The results indicated that the pump fulfills the specified performance.
Software was developed based on the results obtained from the torque test. The sixteen-bit microprocessor controls the operation of the pump, monitoring the position of the pusher-plate in the systolic phase and using a timer in the diastole. The eight-bit microprocessor controls the phase of rotating magnetic field and input voltage of the motor according to the data table derived from the torque test.
The system performance studied with a mock circulator satisfied the design specifications. The pump outflow of 6 1/min was obtained at the rate of around 100 bpm against the afterload of 100 mmHg. The temperature rise and the pump efficiency were around 6 % and 18 C, respectively.
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