Precision electronic absolute and relative position sensing device and method of using same
First Claim
1. A precision electronic absolute position device comprising:
- a scale disposed along a position line defined by a set of position segments;
said scale having machine readable indicia fixed thereon in an arrangement and a combination along the position line such that at least two indicia are disposed in each of said segments and the arrangement of said indicia is such that a line position relationship between the at least two indicia in each segment is unique to define the segment, and the combination of the line positions of the at least two indicia defines a precise position along the position line within each segment;
a machine reading means movable with respect to said scale along the position line such that said reading means extends adjacent said position line a length sufficient for reading the at least two indicia of each segment, for reading and converting to electrical signals the at least two indicia in the at least one segment of said scale such that said electrical signals indicate the line position relationship between the at least two indicia, the combination of the line positions of the at least two indicia and a relative line position of the machine reading means with respect to the indicia;
electronic memory means for retaining and electronically communicating for each segment a segment indication corresponding to the line position relationship between the at least two indicia of each segment, and an indication of precise position along the position line corresponding to the segment indication and the combination of line positions of the at least two indicia of said segment; and
position determining means electrically connected to said machine reading means and said memory means for receiving said electronic signals from said reading means, interpreting said signals by electrically communicating with said memory means to determine a segment indication corresponding to said signals and an indication of position along the position line corresponding to said signals, and determining therefrom an absolute position along said position line of said reading means with respect to said scale.
3 Assignments
0 Petitions
Accused Products
Abstract
A novel position sensing device and novel method for determining position use an electronic memory to retain a look up table for calibrated position indicia on a scale. The position indicia are preferably arranged along the scale so that at least two indicia are positioned at unique distances apart in each length segment of the scale. A reader electrically reads the at least two indicia of a segment and the electronic memory look up table allows the at least two indicia to determine the segment, position within segment, and the position relationship between the position within the segment and the reader. Preferably, the indicia are slits in a scale bar, and the reader is a light source and charge-coupled device. The position of the slits is preferably determined using more than one pixel of the charge-coupled device.
43 Citations
28 Claims
-
1. A precision electronic absolute position device comprising:
-
a scale disposed along a position line defined by a set of position segments; said scale having machine readable indicia fixed thereon in an arrangement and a combination along the position line such that at least two indicia are disposed in each of said segments and the arrangement of said indicia is such that a line position relationship between the at least two indicia in each segment is unique to define the segment, and the combination of the line positions of the at least two indicia defines a precise position along the position line within each segment; a machine reading means movable with respect to said scale along the position line such that said reading means extends adjacent said position line a length sufficient for reading the at least two indicia of each segment, for reading and converting to electrical signals the at least two indicia in the at least one segment of said scale such that said electrical signals indicate the line position relationship between the at least two indicia, the combination of the line positions of the at least two indicia and a relative line position of the machine reading means with respect to the indicia; electronic memory means for retaining and electronically communicating for each segment a segment indication corresponding to the line position relationship between the at least two indicia of each segment, and an indication of precise position along the position line corresponding to the segment indication and the combination of line positions of the at least two indicia of said segment; and position determining means electrically connected to said machine reading means and said memory means for receiving said electronic signals from said reading means, interpreting said signals by electrically communicating with said memory means to determine a segment indication corresponding to said signals and an indication of position along the position line corresponding to said signals, and determining therefrom an absolute position along said position line of said reading means with respect to said scale. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
-
-
22. A precision electronic position device comprising:
-
a scale disposed along a position line defined by a set of position segments; said scale having machine readable indicia fixed thereon disposed along the position line; a machine reading means movable with respect to said scale along the position line for reading and converting said indicia to electrical signals; a memory means comprising a look up table for retaining and a electrically communicating for each indicia an indication of relative position of said indicia along said position line; and position determining means for receiving said electrical signals from said reading means, interpreting said electrical signals using said memory means, and determining therefrom a relative position along said position line of said reading means with respect to said scale. - View Dependent Claims (23, 24)
-
-
25. A method of determining a position of a machine reader with respect to a scale having position indicia thereon comprising:
-
calibrating the scale by recording in an electronic memory determined positions of the indicia thereon as indicated by a position calibration machine so as to create a look up table in the electronic memory of calibrated positions with respect to the scale of each of the position indicia; reading the position indicia of the scale with the machine reader; and using the look up table of the electronic memory to determine the calibrated position of the machine reader with respect to the scale. - View Dependent Claims (26)
-
-
27. A method of determining an absolute position of a machine reader with respect to a scale defined by a set of position segments, comprising:
-
forming position indicia on said scale such that at least two indicia are disposed in an arrangement and a combination in each position segment of said scale and the arrangement of the indicia is such that a position relationship between the at least two indicia in each segment is unique to define each segment and the combination of the positions of the at least two indicia in each segment defines a position within each segment, calibrating the scale by recording in an electronic memory the position relationship between the at least two indicia and a position defined by the combination of the positions of the at least two indicia so as to form a look up table in the electronic memory for each segment of relationship and combination position information, all as indicated by a position calibration machine; reading the at least two indicia of a segment of the scale with the machine reader; and using the look up table of the electronic memory to determine the segment and combination position of the at least two indicia read so as to determine thereby the absolute position of the machine reader with respect to the scale. - View Dependent Claims (28)
-
Specification