Development of methods for adaptive compensation of print misregistration errors based on drive control of web printing presses

Abstract

The purpose of the paper is to develop and experimentally validate methods for adaptive compensation of print registration errors through active control of web press drives. The study focuses on reducing the amplitude of MD and CD deviations in transient and steady operating modes. The methodology combines mathematical modeling of inter-section dynamics with experimental parameter identification. A generalized “drive–tension–position error” interaction model was constructed, taking into account inertia, web elasticity, and gear backlash. Encoder and load cell signals were used for state evaluation and recorded at a sampling rate of 1 kHz. Model parameters were identified using the least squares method based on actual phase shift measurements. An online error estimation algorithm and corrective action generation for shaft speed and phase adjustment were developed. The adaptive controller accounts for inter-section coupling and drive constraints. Experimental validation was carried out on a four-section web press with a format width of 820 mm and 7.5 kW servo drives. During acceleration without compensation, the maximum registration error reached 0.038 mm. After activation of the algorithm, it decreased to 0.017 mm. The settling time was reduced from 126 ms to 78 ms under nominal conditions. The integral oscillation criterion decreased by 43%. When the web tension was disturbed by 20 N, the system restored synchronization within 95 ms. Under a 6 N·m torque impulse, overshoot did not exceed 4.1%. A long production run confirmed stable error levels within 0.014 mm without manual operator intervention. The practical significance lies in the possibility of integrating the algorithm into industrial PLC systems via EtherCAT without modifying the mechanical structure of the press. The proposed approach reduces waste and improves section synchronization accuracy. The scientific novelty consists in the integrated combination of inter-section dynamic modeling and adaptive control that considers real drive and web tension parameters. The obtained results confirm the effectiveness of the compensation methods for serial application in web printing machines.