DYNAMIC VELOCITY-MEASUREMENTS OF PAPER WE BS WITH CORRELATION TECHNIQUES

In this paper a newly developed, contactless velocity measurement syst em for measuring the velocity of 2-dimensional objects will be present ed. The measurement system has already been tested successfully with d ifferent objects e.g. paper webs, rubber, textiles, sheet metal and di fferent road surfaces with a typical measurement error smaller than 1 % dependent on the dynamic response oi the system. The measurement sys tem consists of a sensor unit, transforming the roughness of the surfa ce into two signals with a delay time tau, and a correlation unit ext racting the delay time and calculating the velocity of the surface. Fi rst different pre-examinations will be presented to detemine the accur acy of the measurement system under different environmental conditions . Errors according to the measurement principle will be explained. Sec ond velocity fluctuations of a paper web in different sections of two industrial paper machines will be examined.