一般而言，回授控制在伺服控制系統中扮演了舉足輕重的角色。因此能夠抑制雜訊干擾的回授訊號源，不但可以提升控制系統的性能，更可以降低控制器設計的複雜度。在伺服馬達的轉速控制方面，中高轉速控制皆已相對成熟，而低轉速控制主要會遭遇到的困難在於編碼器所產生的離散位置資訊少，造成速度回授雜訊較大；以及摩擦力對系統所產生的干擾及誤差。有鑒於此，本論文的主要目的在於使用解析度較高的速度觀測器估測法則，搭配論文中所提出的改良型干擾量觀測器補償架構，以解決伺服馬達在低速運轉時觀測器所遭遇的估速與摩擦力干擾問題；另外透過AC伺服馬達搭載一負載進行實驗，分析比較各種摩擦力補償架構間的性能差異，以驗證改良型的干擾量觀測器補償架構確實能提供較好的抑制摩擦力效果。其中，有別於一般使用所費不貲的頻譜分析儀進行系統鑑別，本論文所使用的系統參數估測策略，能夠更簡單且有效的決定系統參數。

Generally speaking, feedback control plays an important role in servo control systems. Therefore, a high-accuracy feedback signal can not only improve the system performance, but also reduce the controller design complexity. When it comes to velocity control of servomotors, high-velocity and medium-velocity control techniques have relatively matured. However, low-velocity control encounters two main difficulties. These difficulties are frictional disturbances within the servomotors and the noise in velocity feedback caused by the lack of discrete-time position information. Hence, the aim of this thesis is to use a velocity observer with higher velocity feedback resolution and a modified disturbance observer compensation structure to deal with the problems that the observer-based method will face under low speed operation. In the experiment, five different friction compensation structures are used to control an AC servomotor to drive a disk mass, respectively. Experimental results indicate that the modified disturbance observer compensation structure provides the best performance. In addition, when identifying a system model, we used a simple model identification strategy which identifies the system more easily and efficiently than the more commonly used and more expensive approach of using a spectrum analyzer.

參考文獻
[1] R. H. Brown, S. C. Schneider, and M. G. Mulligan, “Analysis of algorithms for velocity estimation from discrete position versus time data, ” IEEE Transactions on Industrial Electronics, vol. 39, pp. 11-19, 1992.
[2] R. D. Lorenz and K. W. Van Patten, “High-resolution velocity estimation for all-digital, AC servo drives, ” IEEE Transactions on Industry Applications, vol. 27, pp. 701-705, 1991.
[3] R. D. Lorenz, T. A. Lipo, and D. W. Novotny, “Motion control with induction motors, ” Proceedings of the IEEE, vol. 82, pp. 1215-1240, 1994.
[4] S. Sakai and Y. Hori, “Ultra-low speed control of servomotor using low resolution rotary encoder, ” in Proceedings of the 1995 IEEE IECON 21st International Conference on Industrial Electronics, Control, and Instrumentation, vol. 1, pp. 615-620, 1995.
[5] S. M. Yang and S. J. Ke, “Performance evaluation of a velocity observer for accurate velocity estimation of servo motor drives,” IEEE Transactions on Industry Applications, vol. 36, pp. 98-104, 2000.
[6] F. C. Lin and S. M. Yang, “Adaptive fuzzy logic-based velocity observer for servo motor drives, ” Mechatronics, vol. 13, pp. 229-241, 2003.
[7] L. Kovudhikulrungsri and T. Koseki, “Precise Speed Estimation From a Low-Resolution Encoder by Dual-Sampling-Rate Observer, ” IEEE/ASME Transactions on Mechatronics, vol. 11, pp. 661-670, 2006.
[8] 郭奕玲,沈慧君, 物理學演義, 凡異出版社, 1996。
[9] D. Karnopp, “Computer simulation of slip-stick friction in mechanical dynamic systems, “ASME Journal of Dynamic Systems, Measurement, and Control, ” vol. 107, pp. 100-103, 1985.
[10] B. Armstrong, “Friction: Experimental, Modeling and Compensation,” in Proceedings of the 1988 IEEE International Conference on Robotics and Automation, pp.1422-1427, 1988.
[11] C. Canudas de Wit and V. Seront, “Robust Adaptive Friction Compensation,” in Proceedings of the 1990 IEEE International Conference on Robotics and Automation, vol. 2, pp. 1383-1388, 1990.
[12] C. Canudas de Wit, P. Moel, A. Aubin, B. Broglato and P. Drevet, “Adaptive Friction Compensation in Robot Manipulators: Low-velocities,” in Proceedings of the 1989 IEEE International Conference on Robotics and Automation, pp. 1352-1357, 1989.
[13] D. Haessig and B. Friedland, “On the Modeling and Simulation of Friction,” ASME Journal of Dynamic System, Measurement, and Control, vol. 113, no.3, pp. 354-362, 1991.
[14] C. Canudas de Wit, H. Olsson, K. J. strm and P. Lischinsky, “A new Model for Control of Systems with Friction,” IEEE Transactions on Automatic Control, vol.40, no. 3, pp. 419-425, 1995.
[15] H. S. Lee and M. Tomizuka, “Robust motion controller design for high-accuracy positioning systems,” IEEE Transactions on Industrial Electronics, vol. 43, pp. 48-55, 1996.
[16] T. Umeno and Y. Hori, “Robust speed control of DC servomotors using modern two degrees-of-freedom controller design,” IEEE Transactions on Industrial Electronics, vol. 38, pp. 363-368, 1991.
[17] S. Endo, H. Kobayashi, C. J. Kempf, S. Kobayashi, M. Tomizuka, and Y. Hori, “Robust digital tracking controller design for high-speed positioning systems,” Control Engineering Practice, vol. 4, pp. 527-536, 1996.
[18] E. C. Tseng, M. Y. Cheng, and M. C. Tsai, “Design of a PI-type torque observer for detecting abnormal load,” in Proceedings of the 1998 International Conference on Mechatronics Technology, pp. 147-152, 1998.
[19] M. C. Tsai, E. C. Tseng, and M. Y. Cheng, “Design of a torque observer for detecting abnormal load,” Control Engineering Practice, vol. 8, pp. 259-269, 2000.
[20] 唐佩忠, CNC伺服參數調整專家系統, 第二期, 1993。
[21] F. Ltd, Fanuc AC Servomotor alpha series, Parameter Manual, 1994.
[22] 孫宗瀛,楊英魁, Fuzzy控制：理論,實作與應用, 全華科技圖書, 2005。
[23] 李祖聖, Lecture Notes on Fuzzy Logic Control, 2002。
[24] A. V. Oppenheim, R. W. Schafer, and J. R. Buck, Discrete-Time Signal Processing, Prentice Hall, 1999.
[25] 楊家輝, Lecture Notes on Digital Signal Processing, 2003。
[26] 廖兼賢, 以離散位置資訊作速度與加速度估測之研究, 碩士論文,國立成功大學電機工程學系, 2004。
[27] C. de Wit, “A new model for control of systems with friction,” IEEE Transactions on Automatic Control, vol. 40, pp. 419-425, 1995.
[28] 林銘湧, 精密伺服控制系統之摩擦力分析及補償研究, 碩士論文,逢甲大學自動控制工程學系, 2002。
[29] C. T. Johnson and R. D. Lorenz, “Experimental identification of friction and its compensation in precise, position controlled mechanisms,” IEEE Transactions on Industry Applications, vol. 28, pp. 1392-1398, 1992.
[30] 邱奕範, 命令及摩擦力前饋控制於工具機之研究, 碩士論文,國立成功大學機械工程學系, 2002。
[31] 工研院, PMC32 韌體開發技術手冊 Ver2.0, 2002。
[32] 工研院, EPCIO-601-1 使用手冊, 2002。
[33] Panasonic, AC伺服馬達驅動器 MINAS-A 系列操作說明書。
[34] T. Instruments, TMS320 Float-Point DSP Optimizing C Compiler, 1991.
[35] T. Instruments, TMS320C3x C Source Debugger User's Guide, 1991.
[36] T. Instruments, TMS320C3x User's Guide, 1992.
[37] 張智星, MATLAB程式設計與應用, 2002。
[38] 惠汝生, 自動量測系統-LabView, 全華科技圖書, 2002。
[39] 謝勝治, 圖控式程式語言-LabView, 全華科技圖書, 2002。
[40] F. Ltd, Fanuc AC Servo Unit Maintenance Manual, 1987.