Register System Modeling And Control For Gravure Printing Machines

Gravure printing is the most common means of printing.Compared with other types of printing machines,gravure printing machines have the characteristics of bright color,high anticounterfeiting,high printing durability and seamlessness.Therefore,the gravure printing machine is mainly suitable for copying and engraving of color art,securities,and long-distance printing.Because of its small footprint,short pre-registration time,fast printing speed,and re-overprinting,the electronic shaftless gravure printing machine replaces the shaft gravure printing machine.However,this kind of shaftless gravure printing machine is a non-linear system with multiple input and output variables.Due to the sudden change of the speed of each printing roller,the fluctuation of the tension of the coil,the change of the characteristics of the coil,the registration error will be generated,and the anti-disturbance Registration control has always been a problem that restricts printing accuracy.Traditional control methods have not been able to accommodate the fast response and high precision requirements for tension,speed and print registration in shaftless gravure presses,so modeling and model-based anti-disturbance registration of multicolor shaftless gravure printing press systems Control methods are both necessary and urgent.Aiming at the above problems,this paper takes the unit type electronic shaftless gravure printing machine as the research object,deeply analyzes the various parts of the gravure printing machine and models it,and studies the advanced control strategy of the gravure printing machine system.main tasks as follows:(1)Firstly,the control of the rewinding and unwinding of the gravure printing machine is studied,and the force analysis of the winding and unwinding is carried out respectively,and the tension model of the rewinding and unwinding is established.On this basis,three equivalent control loops are established by cascade control and simulated analysis is performed.Finally,combined with the input and output unit,the tension control system of the gravure printing machine is constructed,and the tension and speed control of the gravure retracting and unwinding roll is realized.(2)For the two-dimensionality of the register error of the gravure printing machine,the longitudinal(in the vertical direction of the printing direction)registration error is analyzed and modeled.Based on the characteristics of this model,a feedforward controller is designed to control.The experimental results show that the designed controller has better anti-disturbance control performance than PID.(3)The focus of the registration is horizontal(same as the printing direction)registration,so the horizontal registration model of the two-color gravure system is established based on the definition of hypothesis and registration.On this basis,a multi-color gravure registration register model is proposed.The model was simulated and the simulation results were compared with the actual gravure machine experimental data to verify the accuracy of the model.(4)Finally,based on the multi-color horizontal registration model,two innovative decoupling methods are proposed.On this basis,the feedforward auto disturbance rejection control strategy is further proposed.For the four-color gravure printing system,the controller design and system package are realized on MATLAB.The experimental results show that the control strategy can effectively suppress various interferences,and the control accuracy and performance are better than the traditional control methods.Finally,through the above work,the various parts of the gravure printing machine form a unified mutual influence system,so that each system of the gravure printing machine forms an organic dynamic whole,which realizes precise control of tension,speed and registration error,and makes the system resistant.The ability to interfere and control has reached a new level.