Hybrid Magnetorheological Transmission for Total Artificial Heart

Abstract

　In this paper, we developed a hybrid magnetorheological transmission for flow balance control of total artificial hearts. The transmission consists of input and output shafts, magnetorheological fluid, permanent magnets, and an electromagnet with adjustable current. A motor rotates the input shaft of the transmission. The transmission transfers the torque to the output shaft that rotates with decelerated rotational speed according to the apparent viscosity of the magnetorheological fluid. First, we analyzed that magnetic flux density distribution according to the current by 3D finite element method. Analyzed results showed that magnetic flux density was regulated by field weakening. Second, we measured the output rotational speed when load torque was 5 mNm and the input rotational speed was 2000 rpm. The difference between input and output rotational speed changed from 4 rpm to 235 rpm since we applied current at 0.5 A. From analyzed and experimental results, it was clarified that the developed transmission had small size, low power consumption and sufficient transmission performance.