[1] SUNG H, FERLAY J, SIEGEL R L et al. Global cancer statistics 2020： GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries[J]. CA： a Cancer Journal for Clinicians, 71, 209-249(2021).

[2] [2] 2汪炜， 颜国正， 王志武， 等. 肠道机器人扩张机构设计与优化［J］. 光学 精密工程， 2017， 25（7）： 1815-1824. doi: 10.3788/OPE.20172507.1815WANGW， YANG ZH， WANGZH W， et al. Design and optimization of expanding mechanism of intestinal robot［J］. Optics and Precision Engineering， 2017， 25（7）： 1815-1824. （in Chinese）. doi: 10.3788/OPE.20172507.1815

[3] [3] 3孟一村， 颜国正， 汪炜， 等. 用于微型胃肠道胶囊机器人供能的U型发射线圈无线能量传输系统设计与实验［J］. 光学 精密工程， 2021， 29（8）： 1881-1890. doi: 10.37188/OPE.20212908.1881MENGY C， YANG ZH， WANGW， et al. Design and experiment： u-shaped transmitting coil wireless power transfer system for micro gastrointestinal capsule robot［J］. Optics and Precision Engineering， 2021， 29（8）： 1881-1890. （in Chinese）. doi: 10.37188/OPE.20212908.1881

[4] [4] 4庄浩宇， 颜国正， 赵凯， 等. 用于肠道机器人的螺旋式平板发射线圈对设计［J］. 光学 精密工程， 2021， 29（1）： 84-90. doi: 10.37188/OPE.20212901.0084ZHUANGH Y， YANG ZH， ZHAOK， et al. Design of spiral flat transmitting coil pair for intestinal robot［J］. Optics and Precision Engineering， 2021， 29（1）： 84-90.（in Chinese）. doi: 10.37188/OPE.20212901.0084

[5] KHAN S R, PAVULURI S K, CUMMINS G et al. Wireless power transfer techniques for implantable medical devices： a review[J]. Sensors （Basel， Switzerland）, 20, 3487(2020).

[6] OKINAGA T, YAMAMOTO T, KOSHIJI K. Transcutaneous energy transmission system for a totally implantable artificial heart using a two-wire Archimedean spiral coil[C], 5407-5410(2021).

[7] MIAH M S, JAYATHURATHNAGE P, ICHELN C et al. High-efficiency wireless power transfer system for capsule endoscope[C], 1-5(2019).

[8] [8] 8邝帅， 颜国正， 王志武， 等. 无线胶囊内窥镜新型接收线圈结构设计与分析方法［J］. 仪器仪表学报， 2019， 40（11）： 55-63. doi: 10.1166/jmihi.2020.3205KUANGSH， YANG ZH， WANGZH W， et al. Structural design and analysis method of new receiving coil for wireless capsule endoscope［J］. Chinese Journal of Scientific Instrument， 2019， 40（11）： 55-63.（in Chinese）. doi: 10.1166/jmihi.2020.3205

[9] [9] 9姜萍萍， 付文浩， 王志武， 等. 用于胃肠道微型机器人的组合螺线管式无线能量发射系统研究［J］. 仪器仪表学报， 2021， 42（2）： 114-122. doi: 10.19650/j.cnki.cjsi.J2007161JIANGP P， FUW H， WANGZH W， et al. Research on combined solenoid wireless power transmitting system for gastrointestinal micro-robot［J］. Chinese Journal of Scientific Instrument， 2021， 42（2）： 114-122.（in Chinese）. doi: 10.19650/j.cnki.cjsi.J2007161

[10] BASAR M R, AHMAD M Y, CHO J et al. Performance evaluation of power transmission coils for powering endoscopic wireless capsules[C], 2263-2266(2015).

[11] [11] 11汪佐儿， 王志武， 汪炜， 等. 用于胃肠道机器人的C型组合式无线能量发射线圈的设计与实验［J］. 仪器仪表学报， 2022， 43（9）： 255-265.WANGZ E， WANGZH W， WANGW， et al. Design and experiment of C-shaped combined wireless power transmitting coils for the gastrointestinal capsule robot［J］. Chinese Journal of Scientific Instrument， 2022， 43（9）： 255-265.（in Chinese）

[12] BASAR M R, AHMAD M Y, CHO J et al. Stable and high-efficiency wireless power transfer system for robotic capsule using a modified Helmholtz coil[J]. IEEE Transactions on Industrial Electronics, 64, 1113-1122(2017).

[13] ZHANG X, LU X H, ZHANG X et al. A novel three-coil wireless power transfer system and its optimization for implantable biomedical applications[J]. Neural Computing and Applications, 32, 7069-7078(2020).

[14] MENG Y, YAN G, JIANG P et al. A novel wireless power transfer system with two parallel opposed coils for gastrointestinal capsule robot[J]. Sensors and Actuators A： Physical, 321, 112413(2021).

[15] YANG Y, CUI J L, CUI X. Design and analysis of magnetic coils for optimizing the coupling coefficient in an electric vehicle wireless power transfer system[J]. Energies, 13, 4143(2020).

[16] YE Z H, SUN Y, LIU X F et al. Power transfer efficiency analysis for omnidirectional wireless power transfer system using three-phase-shifted drive[J]. Energies, 11, 2159(2018).

[17] LIN D Y, ZHANG C, HUI S Y R. Mathematic analysis of omnidirectional wireless power transfer-part-II three-dimensional systems[J]. IEEE Transactions on Power Electronics, 32, 613-624(2017).

[18] NG W M, ZHANG C, LIN D Y et al. Two- and three-dimensional omnidirectional wireless power transfer[J]. IEEE Transactions on Power Electronics, 29, 4470-4474(2014).