System for controlling a rolling mill and method of controlling a rolling mill

Abstract

The invention generally relates to a method of controlled rolling of a metal strip moving through a rolling mill. The method comprises: monitoring a plurality of input control parameters; and generating a plurality of responsive operational control parameters in the rolling mill to selectively control the rolling mill and selectively control a plurality of output parameters of the rolling mill. A control system for controlled rolling of a metal strip moving through a rolling mill is also provided.

1 . A control system for controlled rolling of a metal strip moving through a rolling mill comprising: 
 a plurality of stands each of which includes a plurality of work rolls and a plurality of backup rolls associated with the plurality of work rolls;    a plurality of work roll devices that monitor speed of the work rolls and may actuate speed of the work rolls which work roll devices are associated with at least some of the plurality of work rolls;    a plurality of loading devices and a plurality of loading device position monitors associated with at least some of the plurality of stands;    a plurality of load cells associated with at least some of the plurality of stands;    a plurality of tensiometers located proximate to the metal strip moving through the work rolls;    a plurality of thickness gauges located proximate to the metal strip moving through the work rolls,    a plurality of metal strip speed monitors located proximate to the metal strip moving through the work rolls,    wherein the work roll devices, the loading devices, the loading device position monitors, the load cells, the tensiometers, the thickness gauges and the metal strip speed monitors monitor a plurality of input control parameters to the control system which generates a plurality of responsive operational control parameters in the rolling mill to selectively control the rolling mill and selectively control a plurality of output parameters in the rolling mill.    
   
   
       2 . The system of  claim 1  wherein the work rolls are rotating at a certain speed, 
 wherein the metal strip is moving at a certain speed,    wherein a load is applied to the metal strip,    wherein tension is applied to the metal strip between the stands,    wherein the metal strip has a certain thickness, and    wherein the input control parameters are selected from the group consisting of monitoring a position of the loading devices, the speed of the work rolls, the speed of the metal strip, the load applied to the metal strip, the tension applied to the metal strip between the stands, and the thickness of the metal strip as it exits some of the work rolls.    
   
   
       3 . The system of  claim 1  wherein the work rolls are rotating at a selected speed, and 
 wherein the plurality of responsive operational control parameters are selected from the group consisting of adjusting a position of the loading device and adjusting the speed of the work rolls.    
   
   
       4 . The system of  claim 1  wherein the metal strip has tension between the stands, 
 wherein a load is applied by the work rolls to the metal strip,    wherein the metal strip has a thickness,    wherein the metal strip is moving at a certain speed, and    wherein the output control parameters are selected from the group consisting of adjusting the tension in the metal strip between the stands, the load applied by the rolls to the metal strip, the thickness of the metal strip and the speed of the metal strip.    
   
   
       5 . The system of  claim 1  wherein the responsive operational control parameters are continuously calculated.  
   
   
       6 . The system of  claim 5  wherein a deviation in the responsive operational control parameters is determined and the responsive operational control parameters are adjusted and updated.  
   
   
       7 . The system of  claim 1  wherein the responsive operational control parameters are calculated about every 2 to 5 milliseconds.  
   
   
       8 . The system of  claim 1  wherein tension is applied to the metal strip between the stands, 
 wherein tension in the metal strip is partially controlled by the equation −R −1 (x)B′K(x)x, and    wherein −R −1  is a matrix inverse of a control weighting matrix, B′ is a matrix transposition of a control matrix, K(x) is a state dependent solution of an algebraic Riccati equation and x is a state vector.    
   
   
       9 . The system of  claim 1  wherein tension is applied to the metal strip between the stands, and 
 wherein tension in the metal strip is partially controlled by solving matrix equations.    
   
   
       10 . The system of  claim 1  wherein the metal strip has a certain thickness, 
 wherein the metal strip is moving at a certain speed, and    wherein the thickness of the metal strip is partially controlled by taking a selected metal strip speed and dividing that metal strip speed with another selected metal strip speed and multiplying that product by the metal strip thickness at a selected point which is then multiplied by a correction factor.    
   
   
       11 . A method of controlled rolling of a metal strip moving through a rolling mill comprising: 
 monitoring a plurality of input control parameters; and    generating a plurality of responsive operational control parameters in the rolling mill to selectively control the rolling mill and selectively control a plurality of output parameters of the rolling mill.    
   
   
       12 . The method of  claim 11  wherein the work rolls are moving at a selected speed, 
 wherein tension is applied to the metal strip between a plurality of stands, and    wherein the monitoring of the input control parameters includes monitoring a position of the loading device, the speed of the work rolls and the tension applied to the metal strip between the stands.    
   
   
       13 . The method of  claim 12  wherein a load is applied to the metal strip, 
 wherein the metal strip has a certain thickness, and    wherein the monitoring of the input control parameters further comprises monitoring the load applied to the metal strip and the thickness of the metal strip as it exits some of the work rolls.    
   
   
       14 . The method of  claim 11  wherein the rolling mill has work rolls moving at a selected speed, and 
 wherein the selective control of the rolling mill includes adjusting a position of a loading device associated with a stand and adjusting the speed of the work rolls.    
   
   
       15 . The method of  claim 11  wherein the metal strip has tension between a plurality of stands, 
 wherein a load is applied by the work rolls to the metal strip,    wherein the metal strip has a thickness, and    wherein the output parameters include adjusting the tension in the metal strip between the stands, the load applied by the work rolls to the metal strip and the thickness of the metal strip.    
   
   
       16 . The method of  claim 15  wherein the metal strip is moving at a selected speed, and 
 wherein the output parameters further comprises adjusting the speed of the metal strip.    
   
   
       17 . The method of  claim 11  wherein the responsive operational control parameters are continuously calculated.  
   
   
       18 . The method of  claim 17  wherein a deviation in the responsive operational control parameters is determined and the responsive operational control parameters are adjusted and updated.  
   
   
       19 . The method of  claim 11  wherein the responsive operational control parameters are calculated about every 2 to 5 milliseconds.  
   
   
       20 . The method of  claim 11  wherein tension is applied to the metal strip between a plurality of stands, 
 wherein tension in the metal strip is partially controlled by the equation −R −1 (x)B′K(x)x, and    wherein −R −1  is a matrix inverse of a control weighting matrix, B′ is a matrix transposition of a control matrix, K(x) is a state dependent solution of an algebraic Riccati equation and x is a state vector.    
   
   
       21 . The method of  claim 11  wherein tension is applied to the metal strip between a plurality of stands, and 
 wherein tension in the metal strip is partially controlled by solving matrix equations.    
   
   
       22 . The method of  claim 11  wherein the metal strip has a certain thickness, 
 wherein the metal strip is moving at a certain speed, and    wherein the thickness of the metal strip is partially controlled by taking a selected metal strip speed and dividing that metal strip speed with another selected metal strip speed and multiplying that product by the metal strip thickness at a selected point which is then multiplied by a correction factor.