Abstract: An analysis of the automatic tape laying (ATL)process reveals that ATL is sequential and dynamic process of creeping and reversion of the prepreg under processing pressure.Based on a discussion of the prepreg creep process,the article proposes that the ATL header pressure be adjusted by stages to maintain a steaty processing pressure and therefore ensure the uniformity of prepreg thickness after the laying up.A control algorithm of the ATL header pressure adjustment by stages is advanced on the ATL path control points combied with the ATL CAM software.Corresponding control programs are designed by means of the universal motion and automation controller (UMAC)system,and a control subsystem for the processing pressure adjustment by stages is finally constructed.

Key words: automatic tape laying, processing pressure, creep, control, prepreg