Cold-rolled strip steel length compensation device and method

The invention provides a cold-rolled strip steel length compensation device and method.The length compensation device comprises a base, a tension roller used for detecting the tension of a strip and conveying the strip is installed on the base, and a pressing roller used for pressing the strip downwards is further installed on the base; and the strip output from the cold rolling mill is tensioned by the tension roller and then is directly conveyed to follow-up treatment or is conveyed to follow-up treatment after the oil cylinder drives the pressing roller to press downwards for compensating the length. The short oil cylinder is adopted to drive the arm and drive the swing arm to achieve the action of large-stroke and large-angle swing, the size and the design stroke of the oil cylinder are reduced, the dynamic corresponding speed of the oil cylinder is greatly increased, the rotational inertia of the mechanism is also greatly reduced, the length compensation response is fast, and the tension stability of the