[1] DENG Y T, LI H W, WANG J L, et al.. Speed control for PMSM based on predictive functional control and disturbance observer［J］. Opt. Precision Eng., 2014, 22(6): 1598-1605. (in Chinese)

[2] DENG Y T, LI H W, WANG J L, et al.. Adaptive sliding mode control for AC servo system based on Kalman filter［J］. Opt. Precision Eng., 2014, 22(8): 2088-2095. (in Chinese)

[3] LI H W, DENG Y T, WANG J L. Digital integration of PMSM speed controller based on FPGA［J］. Opt. Precision Eng., 2015, 23(4): 1105-1113. (in Chinese)

[4] DENG Y T, LI H W, WANG J L, et al.. Design of telescope servo system based on DSP and FPGA［J］. Infrared and Laser Engineering, 2014, 43(3): 908-914. (in Chinese)

[5] DENG Y T, LI H W, WANG J L, et al.. Main axes AC servo control system for 2 m telescope［J］. Opt. Precision Eng., 2017, 25(1): 163-171. (in Chinese)

[6] DENG Y T, LI H W, WANG J L, et al.. Large telescope low speed control based on adaptive sliding mode control［J］. Chinese Optics, 2016, 9(6): 713-720. (in Chinese)

[7] XI X C, POO A N, HONG G S. Tracking error-based static friction compensation for a bi-axial CNC machine［J］. Precision Engineering, 2010, 34(3): 480-488.

[8] CHO H C, FADALI M S, LEE K S, et al.. Adaptive position and trajectory control of autonomous mobile robot systems with random friction［J］. IET Control Theory & Applications, 2010, 4(12): 2733-2742.

[9] SU Y X, ZHENG C H, MUELLER P C, et al.. A simple improved velocity estimation for low-speed regions based on position measurements only［J］. IEEE Transactions on Control Systems Technology, 2006, 14(5): 937-942.

[10] CHOI S H, KO J S, KIM I D, et al.. Precise position control using a PMSM with a disturbance observer containing a system parameter compensator［J］. IEE Proceedings-Electric Power Applications, 2005, 152(6): 1573-1577.

[11] JI K H, SHEN J X. A low speed servo motor drive system with disturbance torque observers［J］. Proceedings of the CSEE, 2012, 32(15): 100-106. (in Chinese)

[12] HIRAIDE T, TAKAHASHI K, NANDAYAPA M, et al.. Acceleration control of AC servo motor considering cogging torque at low velocities for haptics［C］. Proceedings of the 2012 IEEE International Symposium on Industrial Electronics, IEEE, 2012: 1668-1673.

[13] SIROTA M J, THOMPSON P M, JEX H R. Azimuth and elevation servo performance of the W.M. Keck telescope［J］. SPIE, 1994, 2199: 126-141.

[14] DENG Y T, LI H W, WANG J L, et al.. Application of structural filter to principal axis system of telescope［J］. Opt. Precision Eng., 2017, 25(4): 900-909. (in Chinese)