Method and Device for the Control of a Feed Mechanism

Abstract

A method for the control of a feed mechanism of a web-fed printing press, i.e., for the control of tensile stress and/or web tension of a printing material web to be taken into the printing unit by the feed mechanism, wherein thereby an actual value is compared with a desired value. According to the discrepancy between the actual value and the desired value, a control device for the tensile stress and/or the web tension produces a correcting variable for the feed mechanism. The actual value of the tensile stress and/or the web tension is determined by calculation based on a model.

1 .- 10 . (canceled) 
     
     
         11 . A method for automatically controlling at least one of a web tensile stress and a web tension of a web of printing material drawn into a printing unit by a feed mechanism, the method comprising:
 comparing an actual value of at least one of a web tensile stress and a web tension of a web of printing material of a drive of the feed mechanism with a setpoint value of the drive of the feed mechanism;   generating a correction variable for the feed mechanism based at least in part on the deviation of the actual value of the drive of the feed mechanism from the setpoint value of the drive of the feed mechanism; and   computing the actual value of the at least one of the web tensile stress and the web tension based on a model.   
     
     
         12 . The method in accordance with claim  10 , wherein an input to the model comprises at least one of:
 a motor torque of a drive of the feed mechanism   an electric current that creates the motor torque,   a friction torque of the feed mechanism,   a web tensile stress value,   a web tension value supplied by a reel changer located upstream of the feed mechanism,   a quantity that forms the web tensile stress value, and   a quantity that forms the web tension value.   
     
     
         13 . The method in accordance with  claim 12 , wherein the friction torque of the feed mechanism is a constant friction torque. 
     
     
         14 . The method in accordance with  claim 13 , wherein the model determines the actual value of at least one of the web tensile stress and the web tension as follows:
     X   IST   =G 2 X   RW   a*[G 1( M   MOT )+ c]     
       where
 X IST  is the computed actual value of the at least one of the web tensile stress and the web tension, 
 X RW  is the value of at least one of the web tensile stress and the value of the web tension of the reel changer, 
 M MOT  is the motor torque of the drive, 
 G 1  and G 2  are smoothing functions, and 
 a and c are constants. 
 
     
     
         15 . The method in accordance with  claim 12 , wherein the friction torque of the feed mechanism is a speed-dependent friction torque and,
 the input to the model further comprises the speed of the drive of the feed mechanism.   
     
     
         16 . The method in accordance with  claim 15 , wherein the model determines the actual value of the at least one of the web tensile stress and the web tension as follows:
     X   IST   =G 2( X   RW )+ a*[G 1( M   MOT )+ m*N   IST   +c]     
       where
 X IST  is the computed actual value of the web tensile stress and/or the web tension, 
 X RW  is the value of the web tensile stress and/or the value of the web tension of the reel changer, 
 M MOT  is the motor torque of the drive, 
 G 1  and G 2  are smoothing functions, 
 N IST  is the speed of the drive, and 
 a, m, and c are constants. 
 
     
     
         17 . The method in accordance with  claim 11 , wherein the method further comprises:
 superimposing the automatic control of the at least one of the web tensile stress and the web tension on an automatic control of a speed of the drive of the feed mechanism; and   outputting an offset for a setpoint value of the speed of the drive of the feed mechanism as a correcting variable.   
     
     
         18 . The method in accordance with  claim 11 , wherein the method further comprises:
 superimposing the automatic control of the at least one of the web tensile stress and the web tension on an automatic control of a state of the drive of the feed mechanism; and   outputting an offset for a setpoint value of the state of the drive of the feed mechanism as a correcting variable.   
     
     
         19 . A device for automatically controlling the at least one of a web tensile stress and a web tension of a web of printing material to be drawn into a printing unit by a feed mechanism, the device comprising:
 a control system for the at least one of the web tensile stress and the web tension configured to generate a correcting variable for the feed mechanism as a function of a deviation of an actual value of the at least one of the web tensile stress and the web tension from a setpoint value of the at least one of the web tensile stress and the web tension,   wherein the device is further configured to determine the actual value the at least one of the web tensile stress and the web tension based on a model.   
     
     
         20 . A device in accordance with  claim 19 , wherein the device for automatic controlling the at least one of a web tensile stress and a web tension is integrated in a drive controller of a drive of the feed mechanism. 
     
     
         21 . The method in accordance with  claim 15 , wherein the speed-dependent friction torque is linearized.