[1] [1] WANG SH Y, LENG X F, HE F Y, et al.. Rotary varifocal mechanism driven by ultrasonic motor［J］. Opt. Precision Eng., 2009, 17(11): 2814-2819.(in Chinese)

          WANG SH Y, LENG X F, HE F Y, et al.. Rotary varifocal mechanism driven by ultrasonic motor［J］. Opt. Precision Eng., 2009, 17(11): 2814-2819.(in Chinese)

[2] [2] ZHANG Q M, WANG H, KIM N, et al.. Direct evaluation of domain-wall and intrinsic contributions to the dielectric and piezoelectric response and their temperature dependence on lead zirconate-titanate ceramics［J］. Journal of Applied Physics, 1994, 75(1): 454-459.

          ZHANG Q M, WANG H, KIM N, et al.. Direct evaluation of domain-wall and intrinsic contributions to the dielectric and piezoelectric response and their temperature dependence on lead zirconate-titanate ceramics［J］. Journal of Applied Physics, 1994, 75(1): 454-459.

[3] [3] ZHANG X L, CHEN Z X, CROSS L E, et al.. Dielectric and piezoelectric properties of modified lead titanate zirconate ceramics from 4.2 to 300 K［J］. Journal of Materials Science, 1983, 18(4): 968-972.

          ZHANG X L, CHEN Z X, CROSS L E, et al.. Dielectric and piezoelectric properties of modified lead titanate zirconate ceramics from 4.2 to 300 K［J］. Journal of Materials Science, 1983, 18(4): 968-972.

[4] [4] XIE J, TIAN SH, XU Y L, et al.. Study of the influence of Sn on PMN-PZT low-temperature stability and piezoelectric properties［J］. Journal of Functional Materials, 2000, 31(1): 77-78, 81.(in Chinese)

          XIE J, TIAN SH, XU Y L, et al.. Study of the influence of Sn on PMN-PZT low-temperature stability and piezoelectric properties［J］. Journal of Functional Materials, 2000, 31(1): 77-78, 81.(in Chinese)

[5] [5] WANG J P, ZHOU H P, JIN J M, et al.. Friction behavior on contact interface of linear ultrasonic motor with hard contact materials［J］. Transactions of Nanjing University of Aeronautics and Astronautics, 2015, 32(2): 174-179.

          WANG J P, ZHOU H P, JIN J M, et al.. Friction behavior on contact interface of linear ultrasonic motor with hard contact materials［J］. Transactions of Nanjing University of Aeronautics and Astronautics, 2015, 32(2): 174-179.

[6] [6] QIU W, MIZUNO Y, NAKAMURA K. Tribological performance of ceramics in lubricated ultrasonic motors［J］. Wear, 2016: 188-195.

          QIU W, MIZUNO Y, NAKAMURA K. Tribological performance of ceramics in lubricated ultrasonic motors［J］. Wear, 2016: 188-195.

[7] [7] LI S, SHAO M C, DUAN C J, et al.. Tribological behavior prediction of friction materials for ultrasonic motors using Monte Carlo-based artificial neural network［J］. Journal of Applied Polymer Science, 2019, 136(10): 47157.

          LI S, SHAO M C, DUAN C J, et al.. Tribological behavior prediction of friction materials for ultrasonic motors using Monte Carlo-based artificial neural network［J］. Journal of Applied Polymer Science, 2019, 136(10): 47157.

[8] [8] LI S, ZHANG N, YANG Z H, et al.. Tailoring friction interface with surface texture for high-performance ultrasonic motor friction materials［J］. Tribology International, 2019, 136: 412-420.

          LI S, ZHANG N, YANG Z H, et al.. Tailoring friction interface with surface texture for high-performance ultrasonic motor friction materials［J］. Tribology International, 2019, 136: 412-420.

[9] [9] QU J J, ZHANG Y H, TIAN X, et al.. Wear behavior of filled polymers for ultrasonic motor in vacuum environments［J］. Wear, 2015, 322: 108-116.

          QU J J, ZHANG Y H, TIAN X, et al.. Wear behavior of filled polymers for ultrasonic motor in vacuum environments［J］. Wear, 2015, 322: 108-116.

[10] [10] GONG W, CHU X CH, LI L T. Research on friction material for traveling wave ultrasonic motor［J］. Piezoelectrics & Acoustooptics, 2003, 25(4): 305-307.(in Chinese)

          GONG W, CHU X CH, LI L T. Research on friction material for traveling wave ultrasonic motor［J］. Piezoelectrics & Acoustooptics, 2003, 25(4): 305-307.(in Chinese)

[11] [11] FAN Y, DING Q J, ZHAO CH SH. Research on PTFE-based friction materials of ultrasonic motor［J］. Lubrication Engineering, 2011, 36(7): 36-39.(in Chinese)

          FAN Y, DING Q J, ZHAO CH SH. Research on PTFE-based friction materials of ultrasonic motor［J］. Lubrication Engineering, 2011, 36(7): 36-39.(in Chinese)

[12] [12] DING Q J, YAO ZH Y, ZHENG W, et al.. Experimental study of friction material adhere to the stator of the traveling wave type rotary ultrasonic motor［J］. Tribology, 2007, 27(6): 578-582.(in Chinese)

          DING Q J, YAO ZH Y, ZHENG W, et al.. Experimental study of friction material adhere to the stator of the traveling wave type rotary ultrasonic motor［J］. Tribology, 2007, 27(6): 578-582.(in Chinese)

[13] [13] ZHAO G, WU C H, ZHANG L C, et al.. Friction and wear behavior of PI and PTFE composites for ultrasonic motors［J］. Polymers for Advanced Technologies, 2018, 29(5): 1487-1496.

          ZHAO G, WU C H, ZHANG L C, et al.. Friction and wear behavior of PI and PTFE composites for ultrasonic motors［J］. Polymers for Advanced Technologies, 2018, 29(5): 1487-1496.

[14] [14] LIU X L, SONG J F, CHEN H C, et al.. Enhanced transfer efficiency of ultrasonic motors with polyimide based frictional materials and surface texture［J］. Sensors and Actuators A-physical, 2019, 295: 671-677.

          LIU X L, SONG J F, CHEN H C, et al.. Enhanced transfer efficiency of ultrasonic motors with polyimide based frictional materials and surface texture［J］. Sensors and Actuators A-physical, 2019, 295: 671-677.

[15] [15] ZHAO CH SH. Ultrasonic Motors Technologies and Applications［M］. Beijing: Science Press, 2007. (in Chinese)

          ZHAO CH SH. Ultrasonic Motors Technologies and Applications［M］. Beijing: Science Press, 2007. (in Chinese)

[16] [16] SONG F Z, YANG Z H, ZHAO G, et al.. Tribological performance of filled PTFE-based friction material for ultrasonic motor under different temperature and vacuum degrees［J］. Journal of Applied Polymer Science, 2017, 134(39): 45358.

          SONG F Z, YANG Z H, ZHAO G, et al.. Tribological performance of filled PTFE-based friction material for ultrasonic motor under different temperature and vacuum degrees［J］. Journal of Applied Polymer Science, 2017, 134(39): 45358.

[17] [17] WANG Q H, ZHENG F, WANG T M. Tribological properties of polymers PI, PTFE and PEEK at cryogenic temperature in vacuum［J］. Cryogenics, 2016, 75: 19-25.

          WANG Q H, ZHENG F, WANG T M. Tribological properties of polymers PI, PTFE and PEEK at cryogenic temperature in vacuum［J］. Cryogenics, 2016, 75: 19-25.