System and method for utilizing a linear sensor

Abstract

Systems and methods for utilizing linear optoelectronic sensors are provided. A plurality of linear sensors may be utilized to obtain velocity measurements of a web material at two points. The acceleration of the web material may be determined from the velocity measurements and a control signal issued to a servo to maintain proper tension along the web material.

1 . A method for draw control of a web material, the method comprising:
 obtaining, using a first linear sensor, a first velocity measurement at a first point along the web material;   obtaining, using a second linear sensor, a second velocity measurement at a second point along the web material;   determining, using the first and second velocity measurements, an acceleration of the web material between the first and second points; and   adjusting tension on the web material based on the determined acceleration.   
     
     
         2 . The method of  claim 1  wherein the web material comprises a woven material. 
     
     
         3 . The method of  claim 1  wherein the web material comprises a non-woven material. 
     
     
         4 . The method of  claim 1  wherein the first linear sensor comprises a one dimensional sensor arranged approximately parallel to a direction of motion of the web material. 
     
     
         5 . The method of  claim 1  wherein the second linear sensor comprises a one dimensional sensor arranged approximately parallel to a direction of motion of the web material. 
     
     
         6 . The method of  claim 1  wherein adjusting tension on the web material based on the determined acceleration comprises modifying a speed of a motor configured to move the web material. 
     
     
         7 . The method of  claim 1  wherein the first linear sensor is located prior to a motor controlling speed of the web material and wherein the second linear sensor is located after the motor. 
     
     
         8 . The method of  claim 1  wherein adjusting tension on the web material based on the determined acceleration comprises sending a control signal to a motor. 
     
     
         9 . A system for draw control of a web material, the system comprising:
 a motor configured to provide motion to the web material;   a first linear sensor configured to obtain a first velocity at a first point along the web material;   a second linear sensor configured to obtain a second velocity at a second point along the web material;   a control unit configured to determine an acceleration of the web material between the first and second points using the first and second velocities and further configured to transmit a control signal to the motor to cause a change in acceleration of the web material thereby maintaining a tension along the web material within a predefined range.   
     
     
         10 . The system of  claim 9  wherein the web material comprises a woven material. 
     
     
         11 . The system of  claim 9  wherein the web material comprises non-woven material. 
     
     
         12 . The system of  claim 9  wherein the first linear sensor comprises a one dimensional sensor arranged approximately parallel to a direction of motion of the web material. 
     
     
         13 . The system of  claim 9  wherein the second linear sensor comprises a one dimensional sensor arranged approximately parallel to a direction of motion of the web material. 
     
     
         14 . A method for performing cut to length operation on a web material, the method comprising:
 determining, using a linear sensor, a length of the web material that has passed a predefined point;   generating a trigger signal to activate an actuator to perform an action on the web material; and   performing, by the actuator, the action on the web material, wherein the trigger signal is timed so that the action is performed on the web material at predefined distances along the web material.   
     
     
         15 . The method of  claim 14  wherein the generation of the trigger signal is performed by a control unit. 
     
     
         16 . The method of  claim 14  wherein the generation of the trigger signal is performed by the linear sensor. 
     
     
         17 . The method of  claim 14  wherein the predefined distance comprises substantially equal distances. 
     
     
         18 . The method of  claim 14  wherein the predefined distance comprises a set of variable distances. 
     
     
         19 . The method of  claim 14  wherein the action comprises cutting the web material. 
     
     
         20 . The method of  claim 14  wherein the action comprises printing on the web material. 
     
     
         21 . A system for performing cut to length operation on a web material, the system comprising:
 a linear sensor configured to determine a length of the web material passing a predefined point;   a control unit operative interconnected with the linear sensor, the control unit configured to generate a trigger signal;   an actuator, responsive to the trigger signal, configured to perform an action on the web material wherein the trigger signal is timed so that the action is performed on the web material at a predefined location on the web material.   
     
     
         22 . A method for ensuring quality control of a web material, the method comprising:
 obtaining a data set of statistical data from one or more points along the web material using one or more linear a sensors; and   calculating a quality score using the set of statistics.   
     
     
         23 . The method of  claim 22  wherein the statistical data comprises image-based data o the web material. 
     
     
         24 . The method of  claim 22  further comprising determining whether the calculated quality score meets a predefined minimum quality score; and
 in response to determining that the quality score does not meet the predefined minimum quality score, rejecting at least a portion of the web material.   
     
     
         25 . The method of  claim 22  wherein the set of statistical data comprises an average speed of the web material. 
     
     
         26 . The method of  claim 22  wherein the set of statistical data comprises a set of changes in tension along the web material.