在工業自動化領域中,機台健康監測是一份相當重要的工作。拜微製程技術的成熟所賜,市面上已經可以取得便宜且性能優越的微機電系統(MEMS)感測元件,我們將溫度感測元件PT1000與MEMS加速規ADXL335集成在一直徑小於一公分的電路板中,封裝後的感測元件(含金屬外殼)也可壓縮在小於一點五公分的直徑範圍。在感測模組體積大幅縮小的情況下,我們可以將感測元件嵌入至機台的特定位置上,當機台處在不同狀態下移動,我們可以量測對應之溫升與震動變化情形,藉以達到監控機台健康之目的,在本次貢獻中,我們改變的機台參數有:滑軌平行度與預壓力。 在調整平行度方面我們將感測器埋入至滑塊正上方的位置並觀察進給平台側向軸(Y軸)回饋的訊號,觀察的結果如下:我們置入間隙片的厚度為1-20條,造成的不平行度範圍為1-14條,我們發現感測器回饋特徵頻率在未調整平行度時約在290Hz左右,當塞入的墊片越厚,造成平行度偏移量越大時,該特徵頻將會有顯著的下降,根據實驗結果顯示,當末端不平行度達5.9條時,機台尾端所激發的特徵頻將從290Hz下降至176Hz,但若墊片厚度超過14條,又會造成特徵頻上升之現象。 在調整螺帽預壓力方面,我們採用更改鋼珠大小的方式做參數上的改變,我們選用(+1、+2、+3、+4μm)的四種大小的鋼珠,並使用市售拉力計和自製的感測器分別觀測預壓力的變化與特徵頻率的變化,我們將感測器埋入至螺帽座並觀察其進給軸(X軸)特徵頻,根據實驗結果顯示,當鋼珠直徑上升時,感測器回饋的特徵頻會從1338Hz上升至1530Hz。 在溫度部分,我們僅建立可用的複合式模組,尚未做訊號分析與比較。
Effective health monitoring in working machines is really important for ensuring high-quality workpieces and low cost on machine maintenance as well as reducing machine downtime in currently automation industrial manufacturing. We developed embedded sensing system for feed drive/ball screw health monitoring. The sensing system includes a 3 mm glass coated platinμm thin film resistance temperature detector (RTD) PT1000 for temperature sensing and a MEMS accelerometer ADXL 335 device for vibration detection. In this study, we built a single axis feed drive system to perform the experiment about linear guides non-parallelism and ball screw preload. In linear guides non-parallelism we find out that if we adjust more non-parallelism, characteristic frequency detected by y axis accelerometer drop from 290Hz to 176Hz. In ball screw preload we find out that if we replace the balls with bigger size, characteristic frequency detected by x axis accelerometer rise from 1338Hz up to 1530Hz. In temperature sensing, we just built up an available module, we haven’t analysed the signals change neither in linear guides adjusting nor in ball screw preload.