結合撓性結構設計與摩擦力模型於線性馬達運動精度影響之研究

Abstract

微米級運動中，摩擦力會導致運動誤差(Kinematic error)，影響定位精度與重複性。為提升控制性能，本研究設計單軸運動平台，使用Dahl與LuGre模型分析摩擦行為，並透過6D雷射干涉儀量測運動精度，量測數據顯示滑軌(Linear guide)間平行度誤差(Straightness error)導致平台變形。為降低所導致摩擦行為不穩定，設計不鏽鋼撓性結構(Flexure structure)降低特定方向剛性吸收應力，以提升運動重複性。實驗結果顯示，撓性結構可使最大靜摩擦力(Stiction friction)與庫倫摩擦力(Coulomb friction)有效降低，並顯著減少摩擦力變化，使用比例積分微分控制器(Proportional-Integral-Derivative, PID)結合前饋控制器，均方根(Root mean square, RMS)之追蹤誤差(Tracking error)為1.84 µm，證實其提升運動精度與穩定性。

In micron-scale motion, friction induces kinematic errors that affect positioning accuracy and repeatability. To enhance control performance, this study designed a single-axis motion platform and analyzed friction behavior using Dahl and LuGre friction models. A 6D laser interferometer was employed to measure motion accuracy. Measurement data revealed that straightness errors between linear guides caused stage deformation. To decrease the results from friction-induced instability, a stainless steel flexure structure was designed to reduce stiffness in specific directions, thereby absorbing stress and improving repeatability. Experimental results showed that the flexure structure effectively reduced both stiction friction and Coulomb friction, furthermore, significantly decreasing friction variations. Through PID controller combining with feedforward controller, the root mean square (RMS) tracking error was reduced to 1.84 µm, demonstrating improvement on motion accuracy and stability.