Hijikata Wataru, Rao Jun, Abe Shodai, Takatani Setsuo, Shinshi Tadahiko
Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama, Japan.
Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan.
Artif Organs. 2015 Jul;39(7):559-68. doi: 10.1111/aor.12440. Epub 2015 Apr 29.
Controlling the flow rate in an implantable rotary blood pump based on the physiological demand made by the body is important. Even though various methods to estimate the flow rate without using a flow meter have been proposed, no adequate method for measuring the blood viscosity, which is necessary for an accurate estimate of the flow rate, without using additional sensors or mechanisms in a noninvasive way, has yet been realized. We have developed a sensorless method for measuring viscosity in magnetically levitated rotary blood pumps, which requires no additional sensors or mechanisms. By applying vibrational excitation to the impeller using a magnetic bearing, we measured the viscosity of the working fluid by measuring the phase difference between the current in the magnetic bearing and the displacement of the impeller. The measured viscosity showed a high correlation (R(2) > 0.992) with respect to a reference viscosity. The mean absolute deviation of the measured viscosity was 0.12 mPa·s for several working fluids with viscosities ranging from 1.18 to 5.12 mPa·s. The proposed sensorless measurement method has the possibility of being utilized for estimating flow rate.
根据身体的生理需求控制植入式旋转血泵中的流速非常重要。尽管已经提出了各种不使用流量计来估计流速的方法，但尚未实现一种在不使用额外传感器或机制的情况下以非侵入性方式测量血液粘度的适当方法，而血液粘度对于准确估计流速是必要的。我们开发了一种用于测量磁悬浮旋转血泵中粘度的无传感器方法，该方法不需要额外的传感器或机制。通过使用磁轴承对叶轮施加振动激励，我们通过测量磁轴承中的电流与叶轮位移之间的相位差来测量工作流体的粘度。测量的粘度与参考粘度显示出高度相关性（R(2) ＞ 0.992）。对于几种粘度范围从1.18至5.12 mPa·s的工作流体，测量粘度的平均绝对偏差为0.12 mPa·s。所提出的无传感器测量方法有可能用于估计流速。
