# US 2019/0168385 A1 · Robot arm calibration device and method thereof

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- Number: US 2019/0168385 A1
- Document ID: US20190168385A1
- Status: Published application
- Kind: A1
- Application number: 15/936,103
- Filed: 2018-03-26
- Published: 2019-06-06
- Earliest claimed: 2017-12-05
- Assignees: Industrial Technology Research Institute
- Applicants: Industrial Technology Research Institute
- Inventors: Yan-Yi DU; Cheng-Chuan CHAO; Shu HUANG; Hung-Hsiu YU
- Web page: https://patentgrep.com/patent/US20190168385A1

## CPC

- B25J 9/1638: {compensation for arm bending/inertia, pay load weight/inertia}
- B25J 9/0087: {Dual arms (double SCARA arms B25J9/043)}
- B25J 9/1692: {Calibration of manipulator}
- B25J 9/1694: {characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion}
- G05B 2219/39045: Camera on end effector detects reference pattern
- Y10S 901/09: Closed loop, sensor feedback controls arm movement
- Y10S 901/46: Sensing device
- B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50})
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A robot arm calibration device is provided, which includes a light emitter, a light sensing module, a cooperative motion controller and a processing module. The light emitter is disposed on at least one robot arm to emit a light beam. The light sensing module is disposed on at least another robot arm to receive the light beam and the light beam is converted into a plurality of image data. The cooperative motion controller is configured to drive the light emitter and light sensing module on at least two robot arms to a corrected position and a position to be corrected, respectively. The processing module receives the image data and the motion parameters of the at least two robot arms to calculate an error value between the corrected position and the position to be corrected, and analyzes the image data to output a corrected motion parameter for modifying motion command.

## Claims

### Claim 1

A robot arm calibration device, comprising:
a light emitter disposed on at least one robot arm to emit a light beam;
a light sensing module disposed on at least another robot arm to receive the light beam and the light beam being converted into a plurality of image data, wherein the light sensing module comprises a plurality of light sensing units, and the light emitter sequentially projects the light beam onto the light sensing units to generate the plurality of image data;
a cooperative motion controller configured to drive the light emitter and the light sensing module on the at least two robot arms to a corrected position and a position to be corrected respectively; and
a processing module for receiving the image data and motion parameters of the at least two robot arms to calculate an error value between the corrected position and the position to be corrected and analyzing the image data to output a corrected motion parameter, wherein the cooperative motion controller modifies a motion command of at least one of the at least two robot arms according to the corrected motion parameter.

### Claim 2 (depends on 1)

The calibration device according to claim 1, wherein the at least two robot arms comprises a corrected robot arm and a robot arm to be corrected, when the two robot arms are in a motion posture, the light emitter and the light sensing module on the two robot arms are held in a relative position, and the light emitter emits the light beam so that the light beam sequentially projects onto the light sensing units, when the two robot arms change to another motion posture, the light emitter and the light sensing module on the two robot arms are held in another relative position, and the light emitter emits the light beam again so that the light beam sequentially projects onto the light sensing units.

### Claim 3 (depends on 2)

The calibration device according to claim 2, wherein the light emitter and the light sensing module are respectively disposed on the corrected robot and the robot arm to be corrected, and the processing module calculates a corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the robot arm to be corrected and the image data corresponding to the light beam for the cooperative motion controller to modify the motion command of the robot arm to be corrected according to the corrected motion parameter.

### Claim 4 (depends on 1)

The calibration device according to claim 1, wherein the at least two robot arms comprises a corrected robot arm and a plurality of robot arms to be corrected, and the light emitter is disposed on the corrected robot arm, and at least one beam splitter further disposed on the corrected robot arm, wherein the light beam is split into a first light beam and a second light beam via the at least one beam splitter, an included angle formed between the first light beam and the second light beam is a fixed angle, the light sensing module comprises two light sensing modules respectively disposed on two of the robot arms to be corrected, and the first light beam and the second light beam respectively project onto the corresponding two light sensing modules.

### Claim 5 (depends on 4)

The calibration device according to claim 4, wherein the at least one beam splitter includes a first beam splitter, a second beam splitter and a third beam splitter, wherein the light beam is split into the first light beam and the second light beam via the first beam splitter, the first light beam is split into a first sub-beam and a second sub-beam via the second beam splitter, and the second light beam is split into a third sub-beam and a fourth sub-beam via the third beam splitter, the light sensing module comprises four light sensing modules respectively disposed on four of the robot arms to be corrected, and the first sub-beam, the second sub-beam, the third sub-beam and the fourth sub-beam respectively project onto the four corresponding light sensing modules.

### Claim 6 (depends on 4)

The calibration device according to claim 4, wherein the light sensing module comprises a first light sensing module and a second light sensing module, and the first light sensing module is disposed on a first robot arm of the robot arms to be corrected, the processing module calculates a first corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the first robot arm to be corrected and the plurality of image data corresponding to the first light beam for the cooperative motion controller to modify the motion command of the first robot arm to be corrected according to the first corrected motion parameter; and
wherein the second light sensing module is disposed on a second robot arm of the robot arms to be corrected, the processing module calculates a second corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the second robot arm to be corrected and the plurality of image data corresponding to the second light beam for the cooperative motion controller to modify the motion command of the second robot arm to be corrected according to the second corrected motion parameter.

### Claim 7 (depends on 1)

The calibration device as claimed in claim 1, wherein the at least two robot arms comprise a corrected robot arm and a plurality of robot arms to be corrected, and the light sensing module is disposed on the corrected robot arm, the light emitter comprises a first light emitter and a second light emitter respectively disposed on two of the robot arms to be corrected, the first light emitter and the second light emitter respectively emit a first light beam and a second light beam, the first light beam projects onto one of the light sensing units and the second light beam projects onto another one of the light sensing units.

### Claim 8 (depends on 7)

The calibration device according to claim 7, wherein the first light emitter is disposed on a first robot arm of the robot arms to be corrected, and the processing module calculates a first corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the first robot arm to be corrected and the plurality of image data corresponding to the first light beam for the cooperative motion controller to modify the motion command of the first robot arm to be corrected according to the first corrected motion parameter; and
wherein the second emitter is disposed on a second robot arm of the robot arms to be corrected, the processing module calculates a second corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the second robot arm to be corrected and the plurality of image data corresponding to the second light beam for the cooperative motion controller to modify the motion command of the second robot arm to be corrected according to the second corrected motion parameter.

### Claim 9 (depends on 1)

The calibration device according to claim 1, further comprising an image capturing device for capturing a pattern mark on the light sensing module, wherein the image capturing device identifies the pattern mark to determine a relative position of the light emitter and the light sensing module.

### Claim 10 (depends on 4)

The calibration device according to claim 4, further comprising an image capturing device for capturing a pattern mark on the light sensing module, wherein the image capturing device identifies the pattern mark to determine a relative position of the light emitter and the light sensing module.

### Claim 11 (depends on 7)

The calibration device according to claim 7, further comprising an image capturing device for capturing a pattern mark on the light sensing module, wherein the image capturing device identifies the pattern mark to determine a relative position of the light emitter and the light sensing module.

### Claim 12

A robot arm calibrating method, comprising:
disposing a light emitter and a light sensing module on at least two robot arms respectively;
driving the light emitter and the light sensing module on the at least two robot arms to a corrected position and a position to be corrected respectively;
emitting a light beam by the light emitter to project the light beam onto the light sensing module;
receiving the light beam by the light sensing module and converting the light beam into a plurality of image data, wherein the light sensing module comprises a plurality of light sensing units, and the light emitter sequentially projects the light beam onto the light sensing units respectively to generate the plurality of image data;
calculating an error value between the corrected position and the position to be corrected according to the plurality of image data and the motion parameters of the at least two robot arms and analyzing the plurality of image data to output a corrected motion parameter; and
modifying a motion command of at least one of the at least two robot arms according to the corrected motion parameter.

### Claim 13 (depends on 12)

The calibration method according to claim 12, wherein the at least two robot arms comprises a corrected robot arm and a robot arm to be corrected, when the two robot arms are in a motion posture, the light emitter and the light sensing module on the two robot arms are held in a relative position, and the light emitter emits the light beam so that the light beam sequentially projects onto the light sensing units, when the two robot arms change to another motion posture, the light emitter and the light sensing module on the two robot arms are held in another relative position, and the light emitter emits the light beam again so that the light beam sequentially projects onto the light sensing units.

### Claim 14 (depends on 13)

The calibration method according to claim 13, wherein the light emitter and the light sensing module are respectively disposed on the corrected robot and the robot arm to be corrected, and the calibration method is performed by calculating the corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the robot arm to be corrected and the image data corresponding to the light beam to modify the motion command of the robot arm to be corrected according to the corrected motion parameter.

### Claim 15 (depends on 12)

The calibration method according to claim 12, wherein the at least two robot arms comprises a corrected robot arm and a plurality of robot arms to be corrected, and the light emitter is disposed on the corrected robot arm, and at least one beam splitter further disposed on the corrected robot arm, wherein the light beam is split into a first light beam and a second light beam via the at least one beam splitter, an included angle formed between the first light beam and the second light beam is a fixed angle, the light sensing module comprises two light sensing modules respectively disposed on two of the robot arms to be corrected, and the first light beam and the second light beam respectively project onto the corresponding two light sensing modules.

### Claim 16 (depends on 15)

The calibration method according to claim 15, wherein the at least one beam splitter includes a first beam splitter, a second beam splitter and a third beam splitter, wherein the light beam is split into the first light beam and the second light beam via the first beam splitter, the first light beam is split into a first sub-beam and a second sub-beam via the second beam splitter, and the second light beam is split into a third sub-beam and a fourth sub-beam via the third beam splitter, the light sensing module comprises four light sensing modules respectively disposed on four of the robot arms to be corrected, and the first sub-beam, the second sub-beam, the third sub-beam and the fourth sub-beam respectively project onto the four corresponding light sensing modules.

### Claim 17 (depends on 15)

The calibration method according to claim 15, wherein the light sensing module comprises a first light sensing module and a second light sensing module, and the first light sensing module is disposed on a first robot arm of the robot arms to be corrected, the calibration method is performed by calculating a first corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the first robot arm to be corrected and the plurality of image data corresponding to the first light beam to modify the motion command of the first robot arm to be corrected according to the first corrected motion parameter; and
wherein the second light sensing module is disposed on a second robot arm of the robot arms to be corrected, the calibration method is performed by calculating a second corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the second robot arm to be corrected and the plurality of image data corresponding to the second light beam to modify the motion command of the second robot arm to be corrected according to the second corrected motion parameter.

### Claim 18 (depends on 12)

The calibration method according to claim 12, wherein the at least two robot arms comprise a corrected robot arm and a plurality of robot arms to be corrected, and the light sensing module is disposed on the corrected robot arm, the light emitter comprises a first light emitter and a second light emitter respectively disposed on two of the robot arms to be corrected, the first light emitter and the second light emitter respectively emit a first light beam and a second light beam, the first light beam projects onto one of the light sensing units and the second light beam projects onto another one of the light sensing units.

### Claim 19 (depends on 18)

The calibration method according to claim 18, wherein the first light emitter is disposed on a first robot arm of the robot arms to be corrected, and the calibration method is performed by calculating a first corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the first robot arm to be corrected and the plurality of image data corresponding to the first light beam to modify the motion command of the first robot arm to be corrected according to the first corrected motion parameter; and
wherein the second emitter is disposed on a second robot arm of the robot arms to be corrected, the calibration method is performed by calculating a second corrected motion parameter according to the motion parameter of the corrected robot arm, the motion parameter of the second robot arm to be corrected and the plurality of image data corresponding to the second light beam to modify the motion command of the second robot arm to be corrected according to the second corrected motion parameter.

### Claim 20 (depends on 12)

The calibration method according to claim 12, further comprising capturing a pattern mark on the light sensing module by an image capturing device, wherein the image capturing device identifies the pattern mark to determine a relative position of the light emitter and the light sensing module.

### Claim 21 (depends on 15)

The calibration method according to claim 15, further comprising capturing a pattern mark on the light sensing module by an image capturing device, wherein the image capturing device identifies the pattern mark to determine a relative position of the light emitter and the light sensing module.

### Claim 22 (depends on 18)

The calibration method according to claim 18, further comprising capturing a pattern mark on the light sensing module by an image capturing device, wherein the image capturing device identifies the pattern mark to determine a relative position of the light emitter and the light sensing module.