Precision 3D scanner base and method for measuring manufactured parts

• US 6,486,963 B1
• Filed: 06/20/2000
• Issued: 11/26/2002
• Est. Priority Date: 06/20/2000
• Status: Expired due to Fees

• Current Assignee: Charles A. Lemaire
• Original Assignee: PPT Vision, Inc. (Datalogic S.p.A.)
• Inventors: Holec, Henry V.
• Primary Examiner(s): Font, Frank G.
• Assistant Examiner(s): Punnoose, Roy M.
• Application Number:
  US09/597,795
• Time in Patent Office: 889 Days
• Field of Search: 356/601, 356/608, 356/611
• US Class Current: 356/601
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures

Abstract

In the context of a machine-vision system for inspecting a part, a method and apparatus to provide high-speed high accuracy 3D (three-dimensional) inspection of manufactured parts by reducing vibration. One system includes a machine-base unit and a table-base portion supported by the base unit. At least two upright portions are connected to the table-base portion. A first scanner support is coupled to the upright portions. An imager head is coupled to the scanner support, wherein the scanner support moves the imager head in a linear motion to scan the object. A connecting member including at least one vibration-absorbing portion connects to the upright portions to absorb vibrations of the upright portions. Also described is a method of reducing vibration in a three-dimensional scanning apparatus used to determine a geometry of an object having at least one surface to be measured, the scanning apparatus having two or more upright portions and a scanning mechanism coupled the upright portions for moving an imaging head. The method includes supporting the scanning mechanism on the upright portions, dampening vibrations of the upright portions, scanning the imaging head relative to the object, receiving image signals representing a three-dimensional geometry of the object into a computer, and calculating with the computer object-geometry data representing three-dimensional geometry of the object.

Claims

1. A machine-vision system for inspecting an object, comprising:

a machine-base unit;

a table-base portion supported by the base unit;

at least two upright portions connected to the table-base portion;

a first scanner support coupled to the upright portions;

an imager head coupled to the scanner support, wherein the scanner support moves the imager head in a linear motion to scan the object; and

a connecting member including at least one vibration-absorbing portion, wherein the connecting member is connected to the upright portions to reduce vibrations of the upright portions.

2. The machine-vision system of claim 1, wherein the vibration-absorbing portion comprises double-sided adhesive tape.

3. The machine-vision system of claim 1, wherein the vibration-absorbing portion comprising double-sided adhesive tape is mounted with one face of the tape attached to two non-coplanar adjacent surfaces of one of the upright portions, and with an opposite face of the tape attached to corresponding mating surfaces of the connecting member.

4. The machine-vision system of claim 1, wherein the first scanner support includes:

a support bar having a substantially horizontal long axis;

a scanner shuttle, wherein the imager head is attached to the scanner shuttle; and

a motor, wherein the motor moves the scanner shuttle relative to the support bar along a first substantially horizontal direction.

5. The machine-vision system of claim 4, wherein the first scanner support is attached to a plurality of second scanner supports, each of the second scanner supports attached to one of the upright portions, wherein each one of the second scanner supports moves the support bar of the first scanner support in a substantially vertical direction.

6. The machine-vision system of claim 4, wherein the motor is a linear motor.

7. The machine-vision system of claim 1, further comprising:

an inspection station that supports the object; and

a loader mechanism that moves the inspection station from a first position where the object is placed onto the inspection station to a second position where the object remains unmoving while the imager head is moved for a scanning operation, and wherein the inspection station is attached to the table-base portion.

8. The machine-vision system of claim 1, further comprising one or more isolation mounts between the machine base unit and the table-base portion to reduce transmission of vibration between the machine base unit and the inspection station.

9. The machine-vision system of claim 1, further comprising:

a computer coupled to the imager head; and

a comparator coupled to the computer, wherein the comparator compares one or more characteristics of the acquired three-dimensional object geometry data with an intended predetermined geometry to produce a signal indicative of any object geometry departure of an actual object geometry from the intended predetermined geometry.

10. The machine-vision system of claim 4, further comprising:

one or more mounts attached to the scanner shuttle of the first scanner support, each imager mount including a first angle adjustment and a second angle adjustment usable to adjust the imager head relative to a line parallel to the direction of scanning and relative to a line perpendicular to the direction of scanning.

11. A method of reducing vibration in a three-dimensional scanning apparatus used to determine a geometry of an object having at least one surface to be measured, the scanning apparatus having two or more upright portions and a scanning mechanism coupled the upright portions for moving an imaging head, the method comprising:

(a) supporting the scanning mechanism on the upright portions;

(b) connecting a member, the member having at least one rigid portion and at least one vibration-absorbing portion, to each upright portion and dampening vibrations of the upright portions;

(c) scanning the imaging head relative to the object;

(d) receiving image signals representing a three-dimensional geometry of the object into a computer; and

(e) calculating with the computer object-geometry data representing three-dimensional geometry of the object.

12. The method of claim 11, wherein the connecting a member and dampening vibrations comprises attaching a rigid connecting member to each upright portion using foam-core double-sided adhesive tape.

13. The method of claim 12, wherein the attaching includes mounting with one face of the tape attached to two noscoplanar adjacent surfaces of one of the upright portions, and with an opposite face of the tape attached to corresponding mating surfaces of the connecting member.

14. The method of claim 11, wherein the scanning function includes:

(f) providing a scan path having a substantially horizontal long axis; and

(g) moving a scanning shuttle along the scan path, wherein the imager head is attached to the scanner shuttle.

15. The method of claim 14, further comprising:

(h) fixing the scan path to a plurality of height-adjustment supports, each of the height-adjustment supports fixed to one of the upright portions; and

i) moving each one of the height-adjustment supports to move the scan path in a substantially vertical direction.

16. The method of claim 14, wherein the moving includes moving using a linear motor.

17. The method of claim 11, further comprising.

(j) supporting the object at an inspection station;

and

(k) moving the inspection station from a first position where the object is placed onto the inspection station to a second position where the object remains unmoving while the imager head is moved for a scanning operation.

18. The method of claim 11, further comprising

(l) isolating vibrations from being transmitted from a floor to the inspection station.

19. The method of claim 11, further comprising:

(m) comparing one or more characteristics of the calculated three-dimensional object geometry data with an intended predetermined geometry to produce a signal indicative of any object geometry departure of an actual object geometry from the intended predetermined geometry; and

(n) controlling a manufacturing process used for the object based on the signal.

20. The method of claim 14, further comprising:

(o) attaching the imager head to the scanner shuttle; and

(p) adjusting a first angle and a second angle to adjust the imager head relative to a line parallel to the direction of scanning and relative to a line perpendicular to the direction of scanning.

21. A machine-vision system for inspecting an objects comprising:

a light source that provides projected light on the object;

an imager, wherein the imager generates signals from the light representative of three-dimensional object-geometry data of the object;

a scanning mechanism that moves the imager relative to the object; and

means for reducing vibration of the imager during a scanning operation, including upright portion means, connecting means coupled to the upright means, and dampening means coupled to the connecting means to reduce vibration of the upright means.

22. The machine-vision system of claim 21, further comprising:

means for reducing vibration of both the object and the imager during a scanning operation.