VP1-08 A Study on Optimization of Power Receiving Coil for Real-Time Vital Signs Measurement in Small Laboratory Animals
Creators: Kota Hase
Tatsuki Omori
Fumihiro Sato
Yoshiki Furuya
Kenichi Sagara
Syu Sasaki and Takeo Yoshikawa
Publisher: name: IEEE
Year: 2025

Animal experiments are useful in drug discovery and medical technology development. In current animal experiments, activity meters are implanted in the bodies of small laboratory animals to measure their vital signs, and the most common method is to supply power to the meter via batteries or a wired connection to a power source. However, there are concerns that these methods may adversely affect the health of laboratory animals due to stress. Therefore, this study proposes a power supply method using wireless power transfer and examines the optimization of the power receiving coil. It is important that the power transmission system is not affected by the position and posture of the laboratory animals. To achieve this, the transmitting coil should be shaped to generate a rotating magnetic field, and the receiving coil should be shaped so that it is chained to the rotating magnetic field at any angle to efficiently receive the rotating magnetic field. Fig.1 shows a model of a power receiving coil based on this idea, in which two curved coils are attached to the upper and lower surfaces of a magnetic core with a circular cross-sectional shape. Since the angles of the upper and lower coils are offset by 90deg, both coils feed the power if the receiving coil is oriented vertically, and if it is oriented horizontally, the coil facing a different direction from the axis of rotation of the circular orbit of the rotating magnetic field feeds the power. Confirm that the devised receiving coil is capable of stable power supply without being affected by its angle or misalignment. The output voltage fluctuations at load release were measured when the receiving coil was fixed on the transmitting coil in the vertical and horizontal orientations, respectively, and rotated 360deg in 15deg increments. The experimental results for the vertical orientation are shown in Fig.2. The experimental results, including the horizontal orientation, confirmed that the output voltage was supplied without interruption, and thus it can be said that stable power supply is possible regardless of the orientation or angle of the receiving coil.References: H. Mei, K. A. Thackston, R. A. Bercich, J. G. R. Jefferys, and P. P. Irazoqui, IEEE. Trans. Biomed. Eng. 64, 775 (2017). S. T. Lee, P. A. Williams, C. E. Braine, D.-T. Lin, S. W. M. John, and P. P. Irazoqui, IEEE Trans. Neural Syst. Rehabilitation Eng. 23, 655 (2015). F. Sato, H. Kotake, T. Takura, T. Sato, H. Matsuki, and S. Yamada, J. Magn. Soc. Jpn. 35, 404 (2011).
Animal experiments are useful in drug discovery and medical technology development. In current animal experiments, activity meters are implanted in the bodies of small laboratory animals to measure their vital signs, and the most common method is to supply power to the meter via batteries or a wired connection to a power source. However, there are concerns that these methods may adversely affect the health of laboratory animals due to stress. Therefore, this study proposes a power supply method using wireless power transfer and examines the optimization of the power receiving coil. It is important that the power transmission system is not affected by the position and posture of the laboratory animals. To achieve this, the transmitting coil should be shaped to generate a rotating magnetic field, and the receiving coil should be shaped so that it is chained to the rotating magnetic field at any angle to efficiently receive the rotating magnetic field. Fig.1 shows a model of a power receiving coil based on this idea, in which two curved coils are attached to the upper and lower surfaces of a magnetic core with a circular cross-sectional shape. Since the angles of the upper and lower coils are offset by 90deg, both coils feed the power if the receiving coil is oriented vertically, and if it is oriented horizontally, the coil facing a different direction from the axis of rotation of the circular orbit of the rotating magnetic field feeds the power. Confirm that the devised receiving coil is capable of stable power supply without being affected by its angle or misalignment. The output voltage fluctuations at load release were measured when the receiving coil was fixed on the transmitting coil in the vertical and horizontal orientations, respectively, and rotated 360deg in 15deg increments. The experimental results for the vertical orientation are shown in Fig.2. The experimental results, including the horizontal orientation, confirmed that the output voltage was supplied without interruption, and thus it can be said that stable power supply is possible regardless of the orientation or angle of the receiving coil.References: H. Mei, K. A. Thackston, R. A. Bercich, J. G. R. Jefferys, and P. P. Irazoqui, IEEE. Trans. Biomed. Eng. 64, 775 (2017). S. T. Lee, P. A. Williams, C. E. Braine, D.-T. Lin, S. W. M. John, and P. P. Irazoqui, IEEE Trans. Neural Syst. Rehabilitation Eng. 23, 655 (2015). F. Sato, H. Kotake, T. Takura, T. Sato, H. Matsuki, and S. Yamada, J. Magn. Soc. Jpn. 35, 404 (2011).