Development and evaluation of motor-driven, pusher-plate-type artificial heart system

提出了一种固定占空比、可变电压的脉宽调制（PWM）算法，用于驱动和控制血泵植入式机电作动器。与直流无刷电机集成的致动器连接到推板式血泵上。电机的旋转通过滚珠丝杠转换成线性运动。用安装在背板上的霍尔效应传感器和附接到板的磁体监测推板的位置。对于泵的开环操作，不需要任何其他监测器。驱动器的尺寸为50 mm OD和30 mm长，重量为480 g。采用8位和16位微处理器分别驱动电机和控制整个系统，详细研究了电机的转矩特性，开发了无反馈控制电机转速和输入电压的软件。结果表明，该泵满足规定的性能要求。16位微处理器控制泵的操作，监测推板在收缩期的位置，并使用微控制器中的计时器。8位微处理器根据转矩测试数据表控制旋转磁场的相位和电机的输入电压，用模拟环行器研究了系统的性能，达到了设计要求。在100 mmHg的后负荷下，以约100 bpm的速率获得6 l/min的泵流出量。温升和泵效率分别为6%和18 ℃左右.

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.