Friction Modeling and Compensation for Feed Drive Motions of CNC Milling Machines

電腦數值控制銑床工具機之進給驅動運動摩擦力建模與補償

葉賜旭(Syh-Shiuh Yeh) ； 孫金柱(Jin-Tsu Sun)

《中國機械工程學刊》 33卷1期 (2012/02) Pp. 39-47

https://doi.org/10.29979/JCSME.201202.0005

摘要

摩擦力存在於電腦數值控制銑床工具機的軸向驅動伺服機構，並且往往會惡化軸向驅動的運動結果。儘管有許多研究展示摩擦力補償可提供良好的軸向運動結果，簡化的摩擦力模型仍然限制電腦數值工具機的軸向驅動運動精度。在本研究中，分離實驗與定速實驗被應用於電腦數值控制銑床工具機的軸向驅動伺服機構，以獲得分析靜摩擦力與速度關聯摩擦力的資料數值。並且，推展靜摩擦力補償表與速度關聯摩擦力模型的過程同時考慮不同的負載條件，以降低摩擦力對軸向運動的不良影響。本研究因此發展整合型的摩擦力模型可考量摩擦力負載效應與摩擦力位置相依性於摩擦力補償；並且，一種前饋摩擦力補償架構則進一步地被發展以控制銑床工具機的軸向驅動運動。許多實驗與運動測試在一台三軸電腦數值控制銑床工具機上完成，以說明本研究所發展摩擦力補償方法的可行性。實驗結果指出，使用本研究所發展的整合摩擦力模型，可使摩擦力補償運動控制系統達到平均最大值29.13%與方均根值42.58%的輪廓誤差降低率。

並列摘要

Friction exists in the feed drive servomechanisms of CNC milling machines and usually deteriorates their motion. Although many studies have demonstrated good motion results by applying friction compensation, the simplified model of friction still limits the motion accuracy of feed drives of CNC machine tools. In this study, breakaway and constant velocity experiments were performed to obtain data for analyzing the static and velocity-dependent friction of a feed drive servomechanism in CNC milling machines. Moreover, different payload conditions were considered in developing friction compensation lookup tables and velocity-dependent friction models for reducing the adverse effects induced by static and velocity-dependent friction. An integrated friction model that considers the payload effects and position dependency of friction was thus developed in this study for friction compensation, and a feedforward friction compensation structure was further developed for controlling the motions of the feed drives of CNC milling machines. Several experiments and motion tests were performed on a three-axis CNC milling machine to illustrate the feasibility of the friction compensation method developed in this study. The experimental results indicate that the friction-compensated motion control system with the integrated friction model developed in this study achieves a reduction of 29.13% (on average) for the maximum value and a reduction of 42.58% (on average) for the root-mean-square value of the contouring errors.

並列關鍵字

friction modeling ； friction compensation ； feed drive motion ； CNC milling machine