一、前言大回转加工件的径向尺寸(以下简称大直径)的在线实时测量,是一个急待解决的难题。大直径(如汽轮机的高压转子,大型船舶或舰艇的地轴等)工件的加工周期长,工艺复杂,毛胚锻件目前尚需进口……。因此,它的造价十分昂贵(如一个高压转子高达十几万元)。一旦报废,经济损失巨大。当前,国家还规定,超过4万元的另部件报废时,经济法庭还要追究法律责任。而大直径工件,多数是由于最后精加工时,尺寸(外径或内径)测量不准确,造成超差而报废。国内目前依然使用机械大卡尺进行大直径尺寸的直接量测。这种 I. INTRODUCTION Online real-time measurement of the radial size of large-swing machining parts (hereinafter referred to as large diameter) is an urgent problem to be solved. Large diameter (such as high-pressure steam turbine turbines, large ships or naval vessels and other geosynchronous) long processing cycle, complex process, the hair forgings still need to import ... .... Therefore, its cost is very expensive (such as a high-pressure rotor up to tens of thousands of yuan). Once scrapped, huge economic losses. At present, the state also stipulates that more than 40,000 yuan when the other parts scrapped, the economic court also held legal responsibility. The large diameter of the workpiece, mostly due to the final finishing, size (OD or ID) measurement is not accurate, resulting in tolerance and scrapped. Domestic still use mechanical calipers for direct measurement of large diameter size. This