Weaving machine with device and method for detecting variations in pile-forming

Weaving machine, in which, in successive weft insertion cycles, at least one weft yarn is inserted between ground warp yarns so as to form together a ground fabric, and pile-warp yarns are interlaced according to a predefined weave pattern into the ground fabric in a figure-forming manner, or are incorporated in a non-figure-forming manner, comprising a yarn tensioning system for keeping at least one pile-warp yarn under tension and a detection device for detecting abnormal variations in pile-forming, wherein this detection device:

• comprises a measuring system, for measuring pile-warp yarn consumption xm of the at least one pile-warp yarn per cycle unit of one or more weft insertion cycles;
• comprises a reference system for determining on the basis of the predefined weave pattern, for each cycle unit, whether the at least one pile-warp yarn is interlaced in a figure-forming manner, and for determining the expected pile-warp yarn consumption xt for the at least one pile-warp yarn;
• and
• comprises a computing system, for comparing, for each cycle unit, the measured pile-warp yarn consumption xm with the expected pile-warp yarn consumption xt when the at least one pile-warp yarn, in this cycle unit, is interlaced in a figure-forming manner, and for, on the basis of this comparison, detecting abnormal variations;
• wherein the yarn tensioning system comprises a local control unit, comprises a drive motor Wand comprises a drive roller, wherein the drive motor is controllable with the local control unit for the driving of the drive roller in order to feed the at least one pile-warp yarn and keep it under tension, and wherein the measuring system is provided to measure the pile-warp yarn consumption xm with the aid of the drive motor and the local control unit, wherein the drive motor Wand the local control unit, for this purpose, form part of the measuring system.