Independently driven, dual sided scanner heads

Patent metadata

Field	Value
Publication number	US-10088305-B2
Application number	US-201414470744-A
Country	US
Kind code	B2
Filing date	Aug 27, 2014
Priority date	Aug 27, 2014
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A scanning measurement system includes independently driven, self-aligning, dual-sided heads. The system is configured to perform a method that includes receiving information associated with a discrepancy in a desired cross direction alignment of a first sensor head and a second sensor head that are disposed on opposite sides of a web of material and that are configured to move in a cross direction relative to the web. The method also includes adjusting a velocity of at least one of the sensor heads based on the received information to improve the cross direction alignment of the first sensor head and the second sensor head.

First claim

What is claimed is:

1. A method comprising:
receiving information associated with a discrepancy in a cross direction alignment of a first sensor head and a second sensor head that are disposed on opposite sides of a web of material, the first sensor head configured to move along a first track in a cross direction relative to the web, the second sensor head configured to move along a second track in the cross direction; and
controlling a first motor associated with the first sensor head to adjust a velocity of the first sensor head relative to a velocity of the second sensor head based on the received information to improve the cross direction alignment of the first sensor head and the second sensor head,
wherein the first motor is different from a second motor associated with the second sensor head, and
wherein the received information comprises first absolute cross direction position information from a first position sensor coupled to the first sensor head and second absolute cross direction position information from a second position sensor coupled to the second sensor head, wherein the first absolute cross direction position information is determined relative to a first calibrated scale along the first track and the second absolute cross direction position information is determined relative to a second calibrated scale along the second track.

2. The method of claim 1 , wherein adjusting the velocity of the first sensor head comprises using the received information in a position feedback control loop to determine an adjusted velocity of the first sensor head.

3. The method of claim 1 , wherein:
adjusting the velocity of the first sensor head comprises using the received information in a position feed forward control loop to determine an adjusted velocity of the first sensor head; and
the position feed forward control loop uses an estimated misalignment based on a historically determined error correction.

4. The method of claim 1 , wherein the received information further comprises a difference in cross direction position or velocity between the first sensor head and the second sensor head.

5. The method of claim 1 , wherein the cross direction alignment of the first sensor head and the second sensor head comprises a desired offset in cross direction positions of the sensor heads.

6. The method of claim 5 , further comprising:
changing the desired offset between a zero offset value and a non-zero offset value.

7. An apparatus comprising:
a first sensor head configured to be disposed on a first side of a web of material, the first sensor head comprising at least one controller configured to:
control a first motor configured to move the first sensor head along a first track in a cross direction relative to the web;
receive information associated with a discrepancy in a cross direction alignment of the first sensor head and a second sensor head disposed on a second side of the web opposite the first side, the second sensor head configured to move along a second track in the cross direction; and
control the first motor to adjust a velocity of the first sensor head relative to a velocity of the second sensor head based on the received information to improve the cross direction alignment of the first sensor head and the second sensor head,

wherein the first motor is different from a second motor configured to move the second sensor head, and
wherein the received information comprises first absolute cross direction position information from a first position sensor coupled to the first sensor head and second absolute cross direction position information from a second position sensor coupled to the second sensor head, wherein the first absolute cross direction position information is determined relative to a first calibrated scale along the first track and the second absolute cross direction position information is determined relative to a second calibrated scale along the second track.

8. The apparatus of claim 7 , wherein the at least one controller is configured to use the received information in a position feedback control loop to determine an adjusted velocity of the first sensor head.

9. The apparatus of claim 7 , wherein:
the at least one controller is configured to use the received information in a position feed forward control loop to determine an adjusted velocity of the first sensor head; and
the position feed forward control loop uses an estimated misalignment based on a historically determined error correction.

10. The apparatus of claim 7 , wherein the received information further comprises a difference in cross direction position or velocity between the first sensor head and the second sensor head.

11. The apparatus of claim 7 , wherein the cross direction alignment of the first sensor head and the second sensor head comprises a desired offset in cross direction positions of the sensor heads.

12. The apparatus of claim 11 , wherein the at least one controller is further configured to change the desired offset between a zero offset value and a non-zero offset value.

13. A system comprising:
a first sensor head and a second sensor head, the first sensor head configured to be disposed on a first side of a web of material and to move along a first track in a cross direction relative to the web, the second sensor head configured to be disposed on a second side of the web opposite the first side and to move along a second track in the cross direction;
a first motor configured to move the first sensor head; and
a second motor configured to move the second sensor head,
wherein the first sensor head is further configured to:
receive information associated with a discrepancy in a cross direction alignment of the first sensor head and the second sensor head; and
control the first motor to adjust a velocity of the first sensor head relative to a velocity of the second sensor head based on the received information to improve the cross direction alignment of the first sensor head and the second sensor head,

wherein the received information comprises first absolute cross direction position information from a first position sensor coupled to the first sensor head and second absolute cross direction position information from a second position sensor coupled to the second sensor head, wherein the first absolute cross direction position information is determined relative to a first calibrated scale along the first track and the second absolute cross direction position information is determined relative to a second calibrated scale along the second track.

14. The system of claim 13 , wherein the first sensor head is configured to use the received information in a position feedback control loop to determine an adjusted velocity of the first sensor head.

15. The system of claim 13 , wherein:
the first sensor head is configured to use the received information in a position feed forward control loop to determine an adjusted velocity of the first sensor head; and
the position feed forward control loop uses an estimated misalignment based on a historically determined error correction.

16. The system of claim 13 , wherein the received information further comprises a difference in cross direction position or velocity between the first sensor head and the second sensor head.

17. The system of claim 13 , wherein the cross direction alignment of the first sensor head and the second sensor head comprises a desired offset in cross direction positions of the sensor heads.

18. A non-transitory computer readable medium embodying a computer program, the compute

Assignees

• Honeywell Asca Inc
• Honeywell Ltd

Inventors

• Beselt Ronald E
• Andronic Cristian
• Hofman Gertjan
• Thalore Sudhir

Classifications

• G01N21/8903

  using a multiple detector array · CPC title

• G01N21/8901

  Optical details; Scanning details (per se G02B) · CPC title

• G01B2210/44

  with detectors on both sides of the object to be measured · CPC title

• G01B7/31

  for testing the alignment of axes · CPC title

• G01B21/24 Primary

  for testing alignment of axes · CPC title