Design of Multi-Coil Wireless Power Transfer System for Gastrointestinal Capsule Robot

doi:10.1007/s12204-021-2263-y

Abstract

Abstract: The existing wireless power transfer (WPT) systems for gastrointestinal capsule robot have the problems of small coupling coefficient and low power transmission efficiency (PTE). The reasons are due to the longdistance between the transmitting coil and the receiving coil and the large difference in size. A new type of WPT system is designed, which uses three sets of small coil pairs to form a power supply unit (PSU), and utilizes multiple PSUs to form a multi-coil WPT system. Compared with single-coil system, the multi-coil system can achieve higher power utilization by switching between PSUs, instead of opening all PSUs. ANSYS Maxwell is used to perform finite element modeling on the PSU, analyzing the characteristics of the transmitting magnetic field. The results of the experiment show that when the distance between the small coil pairs in the PSU is 180 mm, the magnetic field has relatively good uniformity, and the magnetic strength change relative to the center point is less than 5%. The average received power of the system is greater than 800mW, and the PTE is up to 5.1%.

Key words: gastrointestinal capsule robot| multi-coil system| power supply unit| finite element modeling| magnetic
field uniformity

摘要： The existing wireless power transfer (WPT) systems for gastrointestinal capsule robot have the problems of small coupling coefficient and low power transmission efficiency (PTE). The reasons are due to the longdistance between the transmitting coil and the receiving coil and the large difference in size. A new type of WPT system is designed, which uses three sets of small coil pairs to form a power supply unit (PSU), and utilizes multiple PSUs to form a multi-coil WPT system. Compared with single-coil system, the multi-coil system can achieve higher power utilization by switching between PSUs, instead of opening all PSUs. ANSYS Maxwell is used to perform finite element modeling on the PSU, analyzing the characteristics of the transmitting magnetic field. The results of the experiment show that when the distance between the small coil pairs in the PSU is 180 mm, the magnetic field has relatively good uniformity, and the magnetic strength change relative to the center point is less than 5%. The average received power of the system is greater than 800mW, and the PTE is up to 5.1%.

关键词: gastrointestinal capsule robot| multi-coil system| power supply unit| finite element modeling| magnetic
field uniformity

CLC Number:

CHEN Fanji (陈范吉), JIANG Pingping (姜萍萍), YAN Guozheng (颜国正), WANG Wei (汪炜), MENG Yicun (孟一村). Design of Multi-Coil Wireless Power Transfer System for Gastrointestinal Capsule Robot[J]. J Shanghai Jiaotong Univ Sci, 2021, 26(1): 76-83.

References 18

[1]	CAN G, MUSHANI T, AL RAJHI B H, et al. Theglobal burden of cancer pain [J]. Seminars in OncologyNursing, 2019, 35(3): 315-321.
[2]	MOGLIA A, MENCIASSI A, DARIO P, et al. Capsuleendoscopy: Progress update and challenges ahead [J].Nature Reviews Gastroenterology & Hepatology, 2009,6(6): 353-362.
[3]	GUO S, YANG Q, BAI L, et al. Development of multiplecapsule robots in pipe [J]. Micromachines, 2018,9(6): 259.
[4]	KIM H M, YANG S, KIM J, et al. Active locomotion ofa paddling-based capsule endoscope in an in vitro andin vivo experiment (with videos) [J]. GastrointestinalEndoscopy, 2010, 72(2): 381-387.
[5]	CIUTI G, MENCIASSI A, DARIO P. Capsule endoscopy:From current achievements to open challenges[J]. IEEE Reviews in Biomedical Engineering,2011, 4: 59-72.
[6]	SUN T, XIE X, LI G, et al. A two-hop wireless powertransfer system with an efficiency-enhanced power receiverfor motion-free capsule endoscopy inspection [J].IEEE Transactions on Biomedical Engineering, 2012,59(11): 3247-3254.
[7]	HUANG S T, ZHANG W, ZHANG P F, et al. Largescale uniform electromagnetic field simulation basedon Helmholtz coil [J]. Journal of Beijing University ofAeronautics and Astronautics, 2015, 41(2): 203-208(in Chinese).
[8]	SHI Y, YAN G Z, ZHU B Q. Portable wireless powertransmitting system for video capsule endoscopes [J].Optics and Precision Engineering, 2014, 22(1): 132-137 (in Chinese).
[9]	YANG K, YAN G Z, GAO J Y. Design of wirelesspower supply system for robotic capsule [J]. BeijingBiomedical Engineering, 2016, 35(5): 510-515 (in Chinese).
[10]	ZHANG X, LU X, ZHANG X, et al. A novel three-coilwireless power transfer system and its optimization forimplantable biomedical applications [J]. Neural Computingand Applications, 2020, 32(11): 7069-7078.
[11]	WANG W, YAN G, WANG Z, et al. A novel expandingmechanism of gastrointestinal microrobot: Design,analysis and optimization [J]. Micromachines, 2019,10(11): 724.
[12]	LI D W, JIANG P P, KE Q, et al. Optimal designof wireless power transfer system for gastrointestinalrobots [J]. Journal of Shanghai Jiao Tong University,2018, 52(9): 1031-1037 (in Chinese).
[13]	LUO W J, KUNCORO C B D, PRATIKTO, et al.Single-layer transmitter array coil pattern evaluationtoward a uniform vertical magnetic field distribution[J]. Energies, 2019, 12(21): 4157.
[14]	BATRA T, SCHALTZ E, AHN S. Reduction of magneticemission by increasing secondary side capacitorfor ferrite geometry based series-series topologyfor wireless power transfer to vehicles [C]//16th EuropeanConference on Power Electronics and Applications.Piscataway, NJ, USA: IEEE, 2014: 1-11.
[15]	RYUM, KIM J D, CHIN H U, et al. Three-dimensionalpower receiver for in vivo robotic capsules [J]. Medical& Biological Engineering & Computing, 2007, 45(10):997-1002.
[16]	PU P X, YAN G Z, WANG Z W, et al. Design and experimentof expanding mechanism and power receivingcoil for micro intestinal robot [J]. Journal of ShanghaiJiao Tong University, 2019, 53(10): 1143-1150 (in Chinese).
[17]	MENG Y, WANG Z, JIANG P, et al. Optimizationand analysis of Helmholtz-like three-coil wireless powertransfer system applied in gastrointestinal robots [J].Journal of Power Electronics, 2020, 20(4): 1088-1098.
[18]	KE Q, JIANG P P, YAN G Z. Standardized design of the transmitting coils in inductive coupled endoscoperobot driving systems [J]. Journal of Power Electronics,2017, 17(3): 835-847.