ULTRA-LIGHT AND ULTRA-ACCURATE PORTABLE COORDINATE MEASUREMENT MACHINE WITH MULTI-PIECE JOINT ENGAGEMENT

• US 20190249974A1
• Filed: 04/25/2019
• Published: 08/15/2019
• Est. Priority Date: 04/13/2017
• Status: Active Grant

• Current Assignee: SA08700334
• Original Assignee: SA08700334
• Inventors: SAJEDI, Allen
• Granted Patent: US 11,092,419 B2
• Time in Patent Office: Days
• CPC Class Codes: G01B 2210/58 Wireless transmission of information between a sensor or probe and a control or evaluation unit
• CPC Class Codes: G01B 5/0004 Supports G01B5/025 takes precedence
• CPC Class Codes: G01B 5/0016 due to weight on machine tools B23Q11/001
• CPC Class Codes: G01B 5/008 using coordinate measuring machines
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/37193 Multicoordinate measuring system, machine, cmm
• CPC Class Codes: G05B 2219/49054 Active damping of tool vibration
• CPC Class Codes: H04B 1/02 Transmitters

Abstract

A coordinate measurement machine (CMM) includes a manually-positionable articulated arm having first and second ends. The articulated arm includes a plurality of arm segments and a plurality of rotary joints. The first end includes a connector configured to connect to a measurement probe. The second end includes a base for mounting the CMM. A housing of at least one rotary joint from the plurality of rotary joints has a cylindrical outer surface that engages a) the base or b) a connecting portion that connects the at least one rotary joint to another rotary joint from the plurality of rotary joints, the housing welded to the base or to the connecting portion.

Claims

1. A coordinate measurement machine (CMM) comprising:

a manually-positionable articulated arm having first and second ends, the articulated arm including a plurality of arm segments and a plurality of rotary joints;

each of the rotary joints from the plurality of rotary joints including;

first and second bearings;

a shaft that engages an inner diameter of the first bearing and an inner diameter of the second bearing, the shaft configured to rotate about an axis of rotation of the first bearing and the second bearing;

a housing having at least one port that engages at least one of an outer diameter of the first bearing and an outer diameter of the second bearing; and

at least one transducer configured to output an angle signal corresponding to an angle of rotation of the shaft relative to the housing about the axis of rotation;

the first end including a connector configured to connect to a measurement probe; and

the second end including a base configured to be fastened to a mounting surface for mounting the CMM to the mounting surface,

the housing of at least one rotary joint from the plurality of rotary joints having a cylindrical outer surface that engages a) the base or b) a connecting portion that connects the at least one rotary joint to another rotary joint from the plurality of rotary joints, the housing welded to the base or to the connecting portion.

2. The CMM of claim 1, wherein the connecting portion connects the housing to a shaft of the another rotary joint.

3. The CMM of claim 1, wherein the housing is welded to the base such that at least one of the first and second bearings of the at least one rotary joint is disposed below a top surface of the base.

4. The CMM of claim 1, wherein

the base has a cavity formed thereon and a main printed circuit board of the CMM is disposed within the cavity, and

an encoder printed circuit board associated with the at least one rotary joint is disposed within the cavity parallel to the main printed circuit board.

5. The CMM of claim 1, wherein

the base has a cavity formed thereon and an encoder printed circuit board associated with the at least one rotary joint is disposed within the cavity.

6. The CMM of claim 1, wherein measurement error of the CMM introduced by inconsistent welding of the housing to the connecting portion is reduced by implementation of a kinematic model based on a generalized geometric error model.

7. A coordinate measurement machine (CMM) comprising:

a manually-positionable articulated arm having first and second ends, the articulated arm including a plurality of arm segments and a plurality of rotary joints;

an electrical circuit including a main printed circuit board and a plurality of encoder printed circuit boards;

at least one of the rotary joints from the plurality of rotary joints includes;

first and second bearings;

a shaft that engages an inner diameter of the first bearing and an inner diameter of the second bearing, the shaft configured to rotate about an axis of rotation of the first bearing and the second bearing;

a housing having at least one port that engages at least one of an outer diameter of the first bearing and an outer diameter of the second bearing; and

at least one transducer operably connected to an encoder printed circuit board from the plurality of encoder printed circuit boards, the at least one transducer configured to output an angle signal corresponding to an angle of rotation of the shaft relative to the housing about the axis of rotation;

the first end including a connector configured to connect to a measurement probe; and

the second end including a base plate for mounting the CMM, the base plate having a cavity with a bottom opening and a top opening that receives the housing of a first joint from the plurality of rotary joints, the housing welded to the base plate.

8. The CMM of claim 7, wherein the housing is welded to the base such that at least one of the first and second bearings of the first joint is disposed below a top surface of the base plate.

9. The CMM of claim 7, wherein

the main printed circuit board is disposed within the cavity, and

the encoder printed circuit board is disposed within the cavity parallel to the main printed circuit board.

10. The CMM of claim 7, wherein

the encoder printed circuit board is disposed within the cavity.

11. The CMM of claim 7, wherein the base plate has a circular lateral inner surface that encircles the cavity and the encoder printed circuit board is disposed within the circular lateral inner surface of the base plate.

12. The CMM of claim 7, wherein the top opening has a cylindrical inner surface that engages a cylindrical outer surface of the housing.

13. The CMM of claim 7, wherein the housing has a circular flange formed at a distal end of a cylindrical outer surface thereof and the base plate has a corresponding circular groove formed at an end of a cylindrical inner surface thereof, the circular flange engaging the circular groove.

14. The CMM of claim 7, the base plate shaped like a disk, the main printed circuit board disposed inside the disk, the housing partially inserted into a top opening of the disk.

15. A coordinate measurement machine (CMM) comprising:

a manually-positionable articulated arm having first and second ends, the articulated arm including a plurality of arm segments and a plurality of rotary joints;

at least one of the rotary joints from the plurality of rotary joints includes;

first and second bearings;

a shaft that engages an inner diameter of the first bearing and an inner diameter of the second bearing, the shaft configured to rotate about an axis of rotation of the first bearing and the second bearing;

a housing having at least one cylindrical portion having inside thereof a port that engages at least one of an outer diameter of the first bearing and an outer diameter of the second bearing, and a connecting portion that connects the at least one of the rotary joints to another rotary joint from the plurality of rotary joints, the cylindrical portion welded to the connecting portion; and

at least one transducer configured to output an angle signal corresponding to an angle of rotation of the shaft relative to the housing about the axis of rotation;

the first end including a connector configured to connect to a measurement probe; and

the second end including a base plate for mounting the CMM to a mounting surface.

16. The CMM of claim 15, wherein the connecting portion connects the housing to a shaft of the another rotary joint.

17. The CMM of claim 15, wherein measurement error of the CMM introduced by inconsistent welding of the housing to the connecting portion is reduced by implementation of a kinematic model based on a generalized geometric error model.