以速度控制軸向運動之摩擦力補償設計

在驅動伺服機構中會有摩擦力的存在，摩擦力往往造成系統不良影響。而這些摩擦力的影響，可以經由摩擦力數學模型的補償來減少，這種方法在電腦數值工具機的運動控制設計裡很常見。通常前饋摩擦補償結構的補償值大小都是藉由已知的速度命令、位置命令再經過摩擦力模型的計算而來。然而，對於某些用速度控制的伺服馬達組的軸向驅動伺服機構，一般的摩擦力的扭矩補償結構不能直接減少那些因摩擦所產生不良的運動結果。因此，需要設計一個新的以速度為基礎的摩擦補償結構與一個適用的摩擦力模型，才能在一定的範圍裡克服因摩擦所造成的不良影響。在補償結構，開發一個由附加速度指令產生的一個前置過濾器，而且還可以透過微調前置過濾器的參數，來減少運動誤差。在一台軸向驅動運動平台做試驗，來說明摩擦補償方法是可行的。從實驗結果我們能得知，此摩擦力補償方法補償前後位置誤差的RMS改善率有4.77%，補償前後位置誤差最大值改善率有12.16%。

關鍵字

摩擦補償；速度控制；軸向驅動運動

並列摘要

A velocity-based friction compensation scheme is developed for enhancing tool accuracy in computer numerical control (CNC) machining using velocity-controlled servomotors. Friction is known to adversely affect feed drive motion in CNC milling. Model-based friction compensation is widely applied in tool motion control to mitigate these adverse effects. The most widely used friction compensation scheme is feedforward friction torque compensation based on position and velocity commands and an integrated friction model. However, for mechanical systems that are actuated by velocity-controlled servomotor packs, the application of the torque compensation structure requires the introduction of an additional velocity-based friction compensator to achieve motion control. In this study, a directly applicable velocity-based friction compensation structure is proposed. The structure takes as an input an additional velocity command obtained by a prefilter that can be tuned systematically in order to minimize motion error induced by friction. The results of axial motion experimental show that the friction modeling and compensation methods developed in this study achieve a reduction of 4.77% in the root mean square position error and 12.16% in maximum position error.

並列關鍵字

Friction compensation ； Velocity control ； Feed drive motion

參考文獻

[9] S. S. Yeh and J. T. Sun, “Friction Modeling and Compensation for Feed Drive Motions of CNC Milling Machines,” Journal of the Chinese Society of Mechanical Engineers, in press.

[14] 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，台南，2002

[11] Y. T. Shih and A. C. Lee, “Survey on modeling and control for motion systems with friction,” Journal of the Chinese Society of Mechanical Engineers, vol. 24, no. 4, 2003, pp. 337-352.

[1] M. C. Tsai, I. F. Chiu, and M. Y. Cheng, “Design and implementation of command and friction feedforward control for CNC motion controllers,” IEE Proceedings: Control Theory and Applications, vol. 151, no. 1, 2004, pp. 13-20.

[2] S. S. Yeh and H. C. Su, “Development of Friction Identification Methods for Feed Drives of CNC Machine Tools,” International Journal of Advanced Manufacturing Technology, vol. 52, no. 1-4, 2011, pp. 263-278.

國際替代計量

以速度控制軸向運動之摩擦力補償設計

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