System and method for verifying the roll roundness of rolls of paper used for newspapers

摘要

The present invention is directed to a system and method for verifying roll roundness of a cylindrical object and more particularly for verifying the roundness of rolls of papers used for newspaper printing. According to the present invention, a roll rotator is configured with a plurality of ultrasonic sensors, which are activated when a roll of paper is lifted and rotated by the roll rotator. The roll of paper is rotated an entire revolution and a plurality of distance measurements are taken at each sensor. As the readings are taken, a filter algorithm may be applied to remove values that are too far out of range, such as values which are representative of a torn wrapper or other defects in the covering surface of the roll. Once the readings have been taken, an average of the readings is calculated and the roundness algorithm compares each reading with the average for each of the sensors. The difference between each reading and the average are summed and squared and the standard deviation is calculated from the square root of that value. If the standard deviation is greater than a predetermined value the roll fails the roundness test. The predetermined value is dependent on a number of factors, including hardware tolerances, and can be altered for different requirements. In the case of a failure, the roll of paper is set aside in a designated reject area for further analysis. Rolls that pass the roll roundness test are sent on for use in the newspaper printing press.