考量機械性能之NURBS曲線速度規劃運用於補償式插值器

NURBS Curve Feedrate Planning Based on Mechanical Specification for Compensated Interpolator

賴政賢(Cheng-Hsien Lai)

指導教授 ： 陳金聖

國立臺北科技大學/機電學院/自動化科技研究所/碩士(2011年)

https://doi.org/10.6841/NTUT.2011.00458

摘要

本論文針對NURBS曲線運動軌跡，提出ㄧ考量機械性能之NURBS曲線速度規劃運用於補償式插值器的方法，此方法首先利用適應性進給率求出滿足弦誤差與系統的最大進給率限制之各點估測進給率，利用“最低速優先進給率規劃法”搭配不同之加減速規劃；然後，透過本文所提之“補償式插值器”產生精確插值命令送至伺服迴路。由NURBS曲線可計算出各點之曲率並運用適應性進給率求得曲線上各點相對應之估測進給率，然後找尋區域曲率最大之位置且估測進給率低於系統的最大進給率限制做為區段分段點，這些點將該NURBS曲線分為數個區段，再將由適應性進給率所求得之各分段點所對應之估測進給率，利用“最低速優先進給率規劃法”方法進行進給率規劃，此方法可以減少因各區段內之減速距離不足而需重新規劃其他區段進給率之次數，搭配考量機械性能之S-Curve和S-Curve與直線混合的加減速規劃，透過“補償式插值器”計算插值命令，本論文所提之方法可同時考量弦誤差、機械性能、區段距離限制與進給率誤差，產生適當的命令規劃。除了以軟體模擬之外，最後並搭配一PC_based即時多工次系統與一多軸運動平台進行實機測試，驗證本論文所提方法之可行性。

關鍵字

速度規劃 ； 最低速優先進給率規劃法 ； 補償式插值器 ； 插值命令

並列摘要

This paper proposes a NURBS curve feedrate planning based on mechanical specification for compensated interpolator. First, the curvature of a NURBS curve is calculated, and the estimated feedrate corresponding to different curvature and chord error is evaluated by adaptive feedrate. Besides, the break points, which have the local maximum curvature and the corresponding estimated feedrate is smaller then the maximum feedrate limitation, are picked up. The NURBS curve will be separated into many segments by these break points and the estimated feedrate in these break points will be the initial starting and ending feedrate in these segments. Furthermore, the above break points and estimated feedrate will be fed into our proposed lowest feedrate first priority planning (LFFPP) algorithm, which applies two kinds of S-Curve and S-L-Curve ACC/DEC profiles based on mechanical specification, to generate accurate command by compensated interpolator. The proposed method simultaneously satisfies the specifications of chord accuracy, the limitation of maximum velocity, acceleration, jerk and feedrate error in each segment. Finally, two free form curves are simulated and experimented to verify the performance of our proposed methods.

並列關鍵字

NURBS Curve ； Feedrate Planning ； Compensated NURBS Interpolation ； LFFPP ； Adaptive Feedrate ； Break Points

參考文獻

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