System and method to measure force or location on an l-beam

Abstract

Force and location sensing systems and methods are disclosed. A method comprises bending a L-beam at an initially unknown location on a force-supporting portion of the L-beam, the L-beam substantially having a tension side and a compression side, measuring a first local stress at a first location on the tension side, measuring a second local stress at a second location on the tension side, measuring a third local stress at a third location on the compression side, and measuring a fourth local stress at a fourth location on the compression side. A weight-sensing storage system capable of tracking removed items is disclosed with a product image captured via a camera, a plurality of sensors on an L-beam, a first signal from the plurality of sensors indicating a first state prior to change of the product image, and a second signal indicating lower strain on the L-beam than the first signal.

What is claimed is: 
     
         1 . A location-sensing method for approximating location of an object on an L-beam, comprising: receiving an unknown force at an unknown location “x” oriented along a force-receiving portion of an L-beam; sensing a tension stress “t1” from a pair of tension-side sensors; sensing a compression stress “c1” from a pair of compression-side sensors; where a thickness “h1” of a leg portion of the L-beam is known; where a distance “d1” from a lowest tension-side sensor to the force-receiving portion is known; and where a quotient “q1” is obtained from the sum of t1 and c1. 
     
     
         2 . the location-sensing method of  claim 1 , further comprising: approximating the unknown location x=((t1/q1)*h1)/d1 oriented along the force-receiving portion. 
     
     
         3 . the location-sensing method of  claim 2 , further comprising: a load indicator, where the load indicator is imaged on the display after the unknown location has been approximated. 
     
     
         4 . the location-sensing method of  claim 2 , further comprising: sensing a second tension stress “t2”; sensing a second compression stress “c2”; where a second thickness “h2” (200) of leg portion of L-beam is known; where a second distance “d2” ( 202 ) from the sensor to the horizontal section of L-beam or the length of the vertical section is known; where a quotient “q2” is obtained from the sum of t2 and c2; and where x=((t2/q2)*h2)/d2 approximates the unknown location oriented along the L-beam. 
     
     
         5 . the location-sensing method of  claim 4 , where each sensor is a Wheatstone bridge-type sensor. 
     
     
         6 . the location-sensing method of  claim 5 , where each sensor provides an output in local stress units. 
     
     
         7 . the location-sensing method of  claim 6 , where the tension stress value and the compression stress value are not obtained by measuring vertical shear. 
     
     
         8 . the location-sensing method of  claim 1 , further comprising: locating an unknown force on a L-beam by receiving an “x” input and a “y” input; 
     
     
         9 . the location-sensing method of  claim 8 , further comprising: signaling a safety problem if an any of the following is out of a safety threshold, selected from: the “x” input and the “y” input, the “x” input alone, or the “y” input alone. 
     
     
         10 . the location-sensing method of  claim 9 , further comprising: approximating the unknown location.