WO2018119642A1

WO2018119642A1 - Method and device for calibrating tool coordinate system origin of industrial robot

Info

Publication number: WO2018119642A1
Application number: PCT/CN2016/112328
Authority: WO
Inventors: 叶根
Original assignee: 深圳配天智能技术研究院有限公司
Priority date: 2016-12-27
Filing date: 2016-12-27
Publication date: 2018-07-05
Also published as: CN109311155B; CN109311155A

Abstract

Disclosed in an embodiment of the present invention is a method for calibrating a tool coordinate system origin of an industrial robot. The method comprises: controlling an industrial robot to drive a to-be-calibrated tool mounted on a tail end of the robot to move, so that a tool coordinate system origin of the to-be-calibrated tool reaches a fixed reference point along N different tracks; respectively recording a rotation angle of each shaft of the robot when the tool coordinate system origin reaches the reference point each time; and computing coordinate values of the tool coordinate system origin in a flange coordinate system of the robot according to the recorded N sets of rotation angles. In this way, coordinates of a tool coordinate system origin can be calibrated by means of movements of the industrial robot, without an external standard measurement tool.

Description

Method and device for calibrating origin of tool coordinate system of industrial robot

[Technical Field]

Embodiments of the present invention relate to the field of robots, and in particular, to a calibration method and apparatus for an origin of a tool coordinate system of an industrial robot.

【Background technique】

In the use of the robot, it is generally necessary to assemble tools at the end of the robot to achieve the corresponding functions. In order to obtain better processing results, it is often necessary to calibrate the position and posture of the tool relative to the robot end coordinate system (flange coordinate system) after the tool and equipment are completed. At present, the standard measurement tool is generally used to measure the coordinates of the tool coordinate system (Tool Center Point, TCP) in the flange coordinate system, and there are technical problems such as high cost and complicated operation.

[Summary of the Invention]

The embodiment of the invention provides a calibration method and device for the origin of the tool coordinate system of the industrial robot, so as to solve at least part of the problems caused by the calibration of the origin of the tool coordinate system by means of a standard measuring tool in the prior art.

In order to solve the above technical problem, a technical solution adopted by the embodiment of the present invention is to provide a calibration method for the origin of the tool coordinate system of the industrial robot, comprising: controlling the robot to drive the tool to be calibrated installed at the end of the robot, so that the tool to be calibrated The origin of the tool coordinate system reaches a fixed reference point along N different trajectories. When the origin of the tool coordinate system reaches the reference point along different trajectories, the connection between the origin of the flange coordinate system of the robot and the origin of the tool coordinate system does not coincide. , N is an integer greater than or equal to 3; respectively record the rotation angle of each axis of the robot when the origin of the tool coordinate system reaches the reference point; calculate the origin of the tool coordinate system in the flange coordinate system of the robot according to the recorded N sets of rotation angles Coordinate value.

The step of calculating the coordinate value of the tool coordinate system origin in the flange coordinate system of the robot according to the recorded N sets of rotation angles comprises: arbitrarily selecting three groups from the recorded N sets of rotation angles, and calculating a corresponding flange coordinate system. The three sets of homogeneous matrices; the coordinate values of the origin of the tool coordinate system in the flange coordinate system are calculated by three sets of homogeneous matrices.

Wherein, the three groups are randomly selected from the recorded N sets of rotation angles, and the steps of calculating the three sets of homogeneous matrices of the corresponding flange coordinate system include: calculating the corresponding three sets of rotation angles by using the positive kinematics algorithm respectively The three sets of homogeneous matrices of the flange coordinate system are expressed as:

as well as

In the above expression, R ₁ , R ₂ and R ₃ are respectively 3×3 matrices for respectively indicating the direction of the flange coordinate system when the origin of the three tool coordinate system corresponding to the three sets of rotation angles reaches the reference point, O ₁ , O ₂ and O ₃ are 3×1 matrices respectively, which are used to respectively represent the coordinates of the origin of the flange coordinate system when the origin of the three tool coordinate system corresponding to the three sets of rotation angles reaches the reference point.

The step of calculating the coordinate values of the tool coordinate system origin in the flange coordinate system by the three sets of homogeneous matrices includes: calculating the coordinate values of the tool coordinate system origin in the flange coordinate system by using the following formula:

O _T =(R ₁ +R ₃ -2R ₂ ) ^-1 (2O ₂ -O ₁ -O ₃ )

In the above expression, O _T is a 3 × 1 matrix, which is used to represent the coordinate value of the origin of the tool coordinate system in the flange coordinate system.

Wherein, N is an integer greater than or equal to 4, the method further comprising: calculating a tool coordinate system origin in the flange coordinate system according to at least one of the three sets of homogeneous matrices, O _T and the remaining at least one set of rotation angles The error of the coordinate value.

The step of calculating the error of the coordinate value of the tool coordinate system origin in the flange coordinate system according to at least one of the above three sets of homogeneous matrices, O _T and the remaining at least one set of rotation angles comprises: using a forward kinematic algorithm The remaining at least one set of rotation angles is calculated to obtain at least one fourth set of homogeneous matrices of the corresponding flange coordinate system, and expressed as:

In the above expression, R ₄ is a 3×3 matrix, which is used to indicate the direction of the flange coordinate system when the origin of the tool coordinate system corresponding to the remaining at least one set of rotation angles reaches the reference point, and O ₄ is 3×1. a matrix, configured to represent coordinates of an origin of a flange coordinate system when the origin of the tool coordinate system corresponding to the remaining at least one set of rotation angles reaches the reference point; according to at least one of the three sets of homogeneous matrices, O _T and the fourth group The sub-matrix calculates the error of the coordinate value of the tool coordinate system origin in the flange coordinate system.

The step of calculating the error of the coordinate value of the tool coordinate system origin in the flange coordinate system according to at least one of the three sets of homogeneous matrices, the O _T and the fourth set of homogeneous matrices includes: calculating the tool coordinate system by using the following formula The error of the coordinate value of the origin in the flange coordinate system:

T _n =R _n O _T +O _n

T ₄ =R ₄ O _T +O ₄

Err=|T _n -T ₄ |

In the above expression, R _n and O _n are respectively any one of R ₁ , R ₂ and R ₃ and a corresponding one of O ₁ , O ₂ and O ₃ in the above three sets of homogeneous matrices, and err represents an error. value.

In order to solve the above technical problem, a technical solution adopted by the embodiment of the present invention is to provide a calibration device for the origin of the tool coordinate system of the industrial robot, comprising: a control unit for controlling the movement of the tool to be calibrated installed at the end of the robot by the robot The origin of the tool coordinate system of the tool to be calibrated reaches a fixed reference point along N different trajectories. When the origin of the tool coordinate system reaches the reference point along different trajectories, the origin of the flange coordinate system of the robot and the origin of the tool coordinate system The connection lines do not coincide, N is an integer greater than or equal to 3; the recording unit is used to separately record the rotation angle of each axis of the robot when the origin of the tool coordinate system reaches the reference point; the coordinate calculation unit is used for the N groups according to the record The rotation angle calculates the coordinate value of the tool coordinate system origin in the robot's flange coordinate system.

The coordinate calculation unit includes: a first sub-coordinate calculation unit configured to arbitrarily select three groups from the recorded N sets of rotation angles, and calculate three sets of homogeneous matrices of the corresponding flange coordinate system; the second sub-coordinate calculation unit , used to calculate the coordinate value of the origin of the tool coordinate system in the flange coordinate system according to the three sets of homogeneous matrices.

The first sub-coordinate calculation unit uses the forward kinematics algorithm to calculate three sets of homogeneous matrices of the corresponding flange coordinate system from the selected three sets of rotation angles, respectively expressed as:

as well as

The second sub-coordinate calculation unit calculates the coordinate values of the tool coordinate system origin in the flange coordinate system by using the following formula:

O _T =(R ₁ +R ₃ -2R ₂ ) ^-1 (2O ₂ -O ₁ -O ₃ ) (2)

Wherein, N is an integer greater than or equal to 4, the apparatus further includes an error calculation unit, configured to calculate a tool coordinate system origin according to at least one of the three sets of homogeneous matrices, O _T and the remaining at least one set of rotation angles The error of the coordinate value in the blue coordinate system.

The error calculation unit includes: a first sub-error calculation unit configured to calculate, by using a forward kinematics algorithm, at least one fourth group of homogeneous matrices of the corresponding flange coordinate system from the remaining at least one set of rotation angles, and expressed as :

In the above expression, R ₄ is a 3×3 matrix, which is used to indicate the direction of the flange coordinate system when the origin of the tool coordinate system corresponding to the remaining at least one set of rotation angles reaches the reference point, and O ₄ is 3×1. a matrix, configured to represent coordinates of an origin of a flange coordinate system when the origin of the tool coordinate system corresponding to the remaining at least one set of rotation angles reaches the reference point; and a second sub-error calculation unit configured to be based on at least the three sets of homogeneous matrices One, O _T and the fourth set of homogeneous matrices calculate the error of the coordinate values of the tool coordinate system origin in the flange coordinate system.

Wherein, the second sub-error calculation unit calculates the error of the coordinate value of the origin of the tool coordinate system in the flange coordinate system by using the following formula:

T _n =R _n O _T +O _n

T ₄ =R ₄ O _T +O ₄

Err=|T _n -T ₄ |

In order to solve the above technical problem, a technical solution adopted by the embodiment of the present invention is to provide a calibration device for the origin of the tool coordinate system of the industrial robot, including a processor and a memory connected to the processor, wherein the processor runs through the memory The stored program performs the above steps.

The beneficial effects of the embodiments of the present invention are: in the calibration method and device for the origin of the tool coordinate system of the industrial robot provided by the embodiment of the present invention, the calibration tool of the industrial robot can be used for calibration only by using the external standard measurement tool. The tool coordinate system origin coordinates are obtained, and the calibration error can be further given.

[Description of the Drawings]

1 is a schematic structural view of an industrial robot according to a first embodiment of the present invention;

2 is a flow chart showing a calibration method of an origin of a tool coordinate system of an industrial robot according to a second embodiment of the present invention;

3 is a schematic block diagram of a calibration device for an origin of a tool coordinate system of an industrial robot according to a third embodiment of the present invention;

4 is a schematic block diagram of a calibration device for the origin of a tool coordinate system of an industrial robot according to a fourth embodiment of the present invention.

【detailed description】

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

As shown in FIG. 1, FIG. 1 is a schematic structural view of an industrial robot according to a first embodiment of the present invention. The industrial robot of the present embodiment mainly includes a base 11,

robot arms

12, 13, and a tool 14 equipped at the end of the robot arm 13. The mechanical arm 12 and the base 11 and between the

mechanical arms

12 and 13 are respectively connected by the rotating

shafts

15 and 16, and the tool 14 is driven to reach different positions by controlling the rotation of the

rotating shafts

15 and 16.

In order to conveniently describe the movement or pose change of the robot, it is generally prescribed that the robot has the following coordinate system: (1) the world coordinate system, the user specifies a coordinate system fixed to the earth, and the coordinate system does not change during the operation, for example In Fig. 1, the coordinate system defined by the origin o1 and the coordinate axes x1 and y1; (2) the base coordinate system, based on the coordinate system of the robot base, generally does not change during operation, for example, the origin o2 and The coordinate system defined by the axes x2 and y2. Generally speaking, when multiple robots cooperate, each robot has its own base coordinate system, and the world coordinate system is the common reference coordinate system of the base coordinate system; (3) the flange coordinate system, the connection tool at the end of the robot The coordinate system of the robot arm, for example The coordinate system defined by the origin o3 and the coordinate axes x3 and y3 in Fig. 1. In general, when the attitude of the robot changes, the flange coordinate system changes. (4) Tool coordinate system, a coordinate system located on the tool, such as the coordinate system defined by the origin o4 and the coordinate axes x4 and y4 in FIG.

Further, as shown in FIG. 2, FIG. 2 is a flow chart showing a calibration method of the origin of the tool coordinate system of the industrial robot according to the second embodiment of the present invention. In the present embodiment, the tool coordinate system origin coordinates can be obtained by calibration of the industrial robot without the aid of an external standard measurement tool, and the calibration error can be further given. Specifically, the calibration method of this embodiment includes the following steps:

Step 21: The control robot drives the to-be-calibrated tool 14 installed at the end of the robot to move, so that the tool coordinate origin d4 of the tool to be calibrated 14 reaches a fixed position along N different trajectories (for example, the trajectory shown by the dotted line in FIG. 1). Reference point o5;

In this step, N is an integer greater than or equal to 3, and further preferably, when the tool coordinate system origin o4 reaches the reference point o5 along different trajectories, the origin of the flange coordinate system o3 of the robot is connected with the origin o4 of the tool coordinate system. The lines do not coincide, for example, when the tool coordinate system origin o4 reaches the reference point o5 along different tracks, the angle between the above lines is greater than 5 degrees;

Step 22, respectively recording the rotation angle of each axis of the robot (for example, the rotating shafts 15, 16) when the tool coordinate system origin o4 reaches the reference point o5;

In step 23, coordinate values of the tool coordinate system origin o4 in the flange coordinate system of the robot (the coordinate system defined by o3, x3, and y3 in Fig. 1) are calculated according to the recorded N sets of rotation angles.

In this step, it is preferable to arbitrarily select three groups from the recorded N sets of rotation angles, calculate three sets of homogeneous matrices of the corresponding flange coordinate system, and further calculate the origin of the tool coordinate system o4 by the three sets of homogeneous matrices. The coordinate value in the flange coordinate system.

Specifically, using the forward kinematics algorithm, the three sets of homogeneous matrices of the corresponding flange coordinate system are respectively calculated from the selected three sets of rotation angles, which are respectively expressed as:

as well as

Wherein, R ₁ , R ₂ and R ₃ are respectively a matrix of 3×3, which are respectively used to indicate the direction of the flange coordinate system when the origin o4 of the three-tool coordinate system corresponding to the three sets of rotation angles reaches the reference point o5, O ₁ , O ₂ and O ₃ are respectively a matrix of 3 × 1 for respectively indicating the coordinates of the origin o3 of the flange coordinate system when the origin o4 of the three-tool coordinate system corresponding to the three sets of rotation angles reaches the reference point o5. In the above expression, the world coordinate system or the base coordinate system can be used as the reference coordinate system to calculate the direction of the flange coordinate system and the coordinates of the origin o3. Further, the calculation of the homogeneous matrix based on the rotation angle of each axis of the robot using the forward kinematics algorithm is common knowledge in the art, and will not be described herein.

Subsequently, further defined:

Wherein, O _T is a matrix of 3×1, and X _T , Y _T , and Z _{T are} used to represent coordinate values of the tool coordinate system origin o4 in the flange coordinate system. Further, since the tool coordinate system origin o4 corresponding to the three sets of rotation angle data reaches the same reference point o5 during the motion, that is, the coordinate of the tool coordinate system origin o4 corresponding to the three sets of rotation angle data is the same, so it can be listed as follows equation:

Expanded to get:

R ₁ O _T +O ₁ =R ₂ O _T +O ₂

R ₃ O _T +O ₃ =R ₂ O _T +O ₂

Add the above two equations left and right to get:

(R ₁ +R ₃ )O _T +O ₁ +O ₃ =2R ₂ O _T +2O ₂

(R ₁ +R ₃ -2R ₂ )O _T =2O ₂ -O ₁ -O ₃

Finally available:

O _T =(R ₁ +R ₃ -2R ₂ ) ^-1 (2O ₂ -O ₁ -O ₃ )

Furthermore, using the above formula, the coordinate values of the origin of the tool coordinate system in the flange coordinate system can be calculated.

It can be seen that the above method can be used to calibrate the coordinates of the origin of the tool coordinate system origin o4 in the flange coordinate system without the aid of an external standard measuring tool.

Further, as shown in FIG. 2, the method of this embodiment is further preferred and does not have to include:

In step 24, the error of the coordinate value of the tool coordinate system origin o4 in the flange coordinate system is calculated.

At this time, it is necessary to control the tool coordinate system origin o4 to reach the reference point o5 along at least four different trajectories in

steps

21 and 22, and record at least four sets of rotation angles, that is, N is an integer greater than or equal to 4, and according to the above steps Calculating at least one of the above three sets of homogeneous matrices, O _T and the remaining at least one set of rotation angles to calculate an error of the coordinate value of the tool coordinate system origin in the flange coordinate system.

Specifically, at least one fourth set of homogeneous matrices of the corresponding flange coordinate system is calculated from the remaining at least one set of rotation angles using a forward kinematics algorithm and expressed as:

Wherein, R ₄ is a 3×3 matrix, which is used to indicate the direction of the flange coordinate system when the origin of the tool coordinate system corresponding to the remaining at least one set of rotation angles reaches the reference point, and O ₄ is a matrix of 3×1, and is used for Representing the coordinates of the origin of the flange coordinate system when the origin of the tool coordinate system corresponding to the remaining at least one set of rotation angles reaches the reference point, and further according to at least one of the above three sets of homogeneous matrices, O _T and the fourth set of homogeneous matrices Calculate the error of the coordinate value of the tool coordinate system origin in the flange coordinate system. Specifically calculate the error of the coordinate value of the tool coordinate system origin in the flange coordinate system by the following formula:

T _n =R _n O _T +O _n

T ₄ =R ₄ O _T +O ₄

Err=|T _n -T ₄ |

In the above steps, the error of the coordinate value of the tool coordinate system origin in the flange coordinate system may be respectively calculated according to the remaining two or more rotation angles, and finally the calculated two or more errors are averaged to obtain the final Error.

As shown in FIG. 3, FIG. 3 is a tool coordinate system of an industrial robot according to a third embodiment of the present invention. A schematic block diagram of the calibration device for the point. The calibration device of this embodiment includes a control unit 31, a recording unit 32, and a coordinate calculation unit 33. The control unit 31 is configured to control the movement of the tool to be calibrated 14 installed at the end of the robot, so that the origin o4 of the tool coordinate system of the tool to be calibrated reaches a fixed reference point o5 along N different trajectories, where N is greater than or An integer equal to 3. When the tool coordinate system origin o4 reaches the reference point o5 along different trajectories, the origin of the robot's flange coordinate system origin o3 does not coincide with the line of the tool coordinate system origin o4.

The recording unit 32 is for separately recording the rotation angle of each axis of the robot each time the tool coordinate system origin o4 reaches the reference point o5. The coordinate calculation unit 33 is configured to calculate the coordinate value of the tool coordinate system origin o4 in the flange coordinate system of the robot based on the recorded N sets of rotation angles.

Further, the calculation unit 33 includes a first sub-coordinate calculation unit 331 and a second sub-coordinate calculation unit 332. The first sub-coordinate calculation unit 331 is configured to arbitrarily select three groups from the recorded N sets of rotation angles, and calculate three sets of homogeneous matrices of the corresponding flange coordinate system, and the second sub-coordinate calculation unit 332 is configured to The group homogeneous matrix is calculated to obtain the coordinate value of the origin of the tool coordinate system in the flange coordinate system.

Specifically, the first sub-coordinate calculation unit 331 calculates the three sets of homogeneous matrices of the corresponding flange coordinate system by using the positive kinematics algorithm from the selected three sets of rotation angles, respectively:

as well as

In the above expression, R ₁ , R ₂ and R ₃ are respectively 3×3 matrices for respectively indicating the direction of the flange coordinate system when the origin o2 of the three-tool coordinate system corresponding to the three sets of rotation angles reaches the reference point o5. , O ₁ , O _{2 ,} and O ₃ are respectively a matrix of 3×1, and are used to respectively represent the coordinates of the origin o3 of the flange coordinate system when the origin o4 of the three-tool coordinate system corresponding to the three sets of rotation angles reaches the reference point o5.

The second sub-coordinate calculation unit 332 calculates the coordinate value of the tool coordinate system origin o4 in the flange coordinate system using the following formula:

O _T =(R ₁ +R ₃ -2R ₂ ) ^-1 (2O ₂ -O ₁ -O ₃ ) (2)

In the above expression, O _T is a 3 × 1 matrix for indicating the coordinate value of the tool coordinate system origin o4 in the flange coordinate system.

Still further preferred embodiment, N is an integer greater than or equal to 4, said apparatus further comprising a calibration error calculating unit 34, according to the above-described three homogeneous matrix of at least one, O _T and at least a set of rotating the remaining The angle calculation tool coordinate system origin o4 error in the coordinate value of the flange coordinate system.

Specifically, the error calculation unit 34 includes a first sub-error calculation unit 341 and a second sub-error calculation unit 342. The first sub-error calculating unit 34 is configured to calculate at least one fourth set of homogeneous matrices of the corresponding flange coordinate system from the remaining at least one set of rotation angles by using a forward kinematics algorithm, and is expressed as:

In the above expression, R ₄ is a 3×3 matrix for indicating the direction of the flange coordinate system when the tool coordinate system origin o4 corresponding to the remaining at least one set of rotation angles reaches the reference point o5, and O ₄ is 3×. A matrix of 1 for indicating the coordinates of the origin of the flange coordinate system when the tool coordinate system origin o4 corresponding to the remaining at least one set of rotation angles reaches the reference point o5.

The second sub-error calculating unit 342 is configured to calculate an error of the coordinate value of the tool coordinate system origin o4 in the flange coordinate system according to at least one of the three sets of homogeneous matrices, O _T and the fourth set of homogeneous matrices. Specifically, the second sub-error calculation unit 342 calculates the error of the coordinate value of the tool coordinate system origin o4 in the flange coordinate system using the following formula:

T _n =R _n O _T +O _n

T ₄ =R ₄ O _T +O ₄

Err=|T _n -T ₄ |

As shown in FIG. 4, FIG. 4 is a schematic block diagram of a calibration device for the origin of the tool coordinate system of the industrial robot according to the fourth embodiment of the present invention. The calibration apparatus of this embodiment includes a processor 41 and a memory 42. The processor 41 is connected to the memory 42 and executes the steps in the calibration method shown in the second embodiment of the present invention described with reference to Fig. 2 by running a program stored in the memory 42.

In summary, those skilled in the art can easily understand that in the calibration method and device for the origin of the tool coordinate system of the industrial robot provided by the embodiment of the present invention, it is only necessary to pass the self-movement of the industrial robot without using the external standard measurement tool. The tool coordinate system origin coordinates can be calibrated and the calibration error can be further given.

The above is only the embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformation, or direct or indirect, using the description of the present invention and the contents of the drawings. The use of other related technical fields is equally included in the scope of patent protection of the present invention.

Claims

A method for calibrating an origin of a tool coordinate system of an industrial robot, comprising:

Controlling the robot to drive the tool to be calibrated installed at the end of the robot, so that the origin of the tool coordinate system of the tool to be calibrated reaches a fixed reference point along N different trajectories, wherein the origin of the tool coordinate system arrives along different trajectories In the reference point, the origin of the flange coordinate system origin of the robot does not coincide with the line connecting the origin of the tool coordinate system, and N is an integer greater than or equal to 3;

Recording, respectively, a rotation angle of each axis of the robot each time the origin of the tool coordinate system reaches the reference point;

The coordinate values of the tool coordinate system origin in the flange coordinate system of the robot are calculated according to the recorded N sets of rotation angles.
The method according to claim 1, wherein the step of calculating the coordinate value of the tool coordinate system origin in the flange coordinate system of the robot according to the recorded N sets of rotation angles comprises:

Three groups are randomly selected from the recorded N sets of rotation angles, and three corresponding homogeneous matrices of the flange coordinate system are calculated;

The coordinate values of the origin of the tool coordinate system in the flange coordinate system are calculated by the three sets of homogeneous matrices.
The method according to claim 2, wherein the step of arbitrarily selecting three groups from the recorded N sets of rotation angles, and calculating the corresponding three sets of homogeneous matrices of the flange coordinate system comprises:

Using the forward kinematics algorithm, the three sets of homogeneous matrices of the corresponding flange coordinate system are respectively calculated from the selected three sets of rotation angles, which are respectively expressed as:

as well as

Wherein R 1 , R 2 and R 3 are respectively a matrix of 3×3 for respectively representing the flange coordinate system when the origin of the tool coordinate system corresponding to the three sets of rotation angles reaches the reference point The directions, O 1 , O 2 and O 3 are respectively 3×1 matrices for respectively representing the flange coordinates when the origin of the tool coordinate system corresponding to the three sets of rotation angles reaches the reference point The coordinates of the origin.
The method according to claim 3, wherein the step of calculating the coordinate values of the tool coordinate system origin in the flange coordinate system by the three sets of homogeneous matrices comprises:

Calculating the coordinate values of the origin of the tool coordinate system in the flange coordinate system by using the following formula:

O T =(R 1 +R 3 -2R 2 ) -1 (2O 2 -O 1 -O 3 )

Wherein, O T is a matrix of 3×1 for indicating the coordinate value of the origin of the tool coordinate system in the flange coordinate system.
The method according to claim 4, wherein N is an integer greater than or equal to 4, the method further comprising:

Calculating an error of a coordinate value of the tool coordinate system origin in the flange coordinate system according to at least one of the three sets of homogeneous matrices, O T and the remaining at least one set of rotation angles.
The method according to claim 5, wherein said calculating said tool coordinate system origin in said flange coordinate system according to at least one of three sets of homogeneous matrices, O T and remaining remaining at least one set of rotation angles The steps of the error in the coordinate values include:

Calculating, by using a positive kinematics algorithm, at least one fourth set of homogeneous matrices of the corresponding flange coordinate system from the remaining at least one set of rotation angles, and expressing:

Wherein R 4 is a 3×3 matrix, which is used to indicate the direction of the flange coordinate system when the tool coordinate system origin corresponding to the remaining at least one set of rotation angles reaches the reference point; O 4 is 3× a matrix of 1 for indicating coordinates of an origin of the flange coordinate system when the tool coordinate system origin corresponding to the remaining at least one set of rotation angles reaches the reference point;

Calculating an error of a coordinate value of the tool coordinate system origin in the flange coordinate system according to at least one of the three sets of homogeneous matrices, O T and the fourth set of homogeneous matrices.
The method according to claim 6, wherein said calculating said tool coordinate system origin according to said method according to at least one of said three sets of homogeneous matrices, O T and said fourth set of homogeneous matrices The steps of the error of the coordinate values in the blue coordinate system include:

Calculating the error of the coordinate value of the origin of the tool coordinate system in the flange coordinate system by using the following formula:

T n =R n O T +O n

T 4 =R 4 O T +O 4

Err=|T n -T 4 |

Wherein R n and O n are respectively any one of R 1 , R 2 and R 3 and a corresponding one of O 1 , O 2 and O 3 in the three sets of homogeneous matrices, and err represents an error value.
A calibration device for an origin coordinate of a tool coordinate system of an industrial robot, characterized in that the device comprises:

a control unit, configured to control the movement of the tool to be calibrated installed at the end of the robot, so that the origin of the tool coordinate system of the tool to be calibrated reaches a fixed reference point along N different trajectories, wherein the tool coordinate system origin When the reference point is reached along different trajectories, the origin of the flange coordinate system origin of the robot does not coincide with the line connecting the origin of the tool coordinate system, and N is an integer greater than or equal to 3;

a recording unit, configured to separately record a rotation angle of each axis of the robot each time the origin of the tool coordinate system reaches the reference point;

And a coordinate calculation unit configured to calculate coordinate values of the tool coordinate system origin in the flange coordinate system of the robot according to the recorded N sets of rotation angles.
The calibration device according to claim 8, wherein the coordinate calculation unit comprises:

a first sub-coordinate calculation unit, configured to arbitrarily select three groups from the recorded N sets of rotation angles, and calculate three corresponding homogeneous matrices of the flange coordinate system;

And a second sub-coordinate calculation unit configured to calculate coordinate values of the tool coordinate system origin in the flange coordinate system according to the three sets of homogeneous matrices.
The calibration device according to claim 9, wherein the first sub-coordinate calculation unit calculates three sets of the corresponding flange coordinate systems by using the positive kinematics algorithm from the selected three sets of rotation angles. The matrix is expressed as:

as well as

Wherein R 1 , R 2 and R 3 are respectively a matrix of 3×3 for respectively representing the flange coordinate system when the origin of the tool coordinate system corresponding to the three sets of rotation angles reaches the reference point The directions, O 1 , O 2 and O 3 are respectively 3×1 matrices for respectively representing the flange coordinates when the origin of the tool coordinate system corresponding to the three sets of rotation angles reaches the reference point The coordinates of the origin.
The calibration device according to claim 10, wherein the second sub-coordinate calculation unit calculates a coordinate value of the tool coordinate system origin in the flange coordinate system by using the following formula:

O T =(R 1 +R 3 -2R 2 ) -1 (2O 2 -O 1 -O 3 )

Wherein, O T is a matrix of 3×1 for indicating the coordinate value of the origin of the tool coordinate system in the flange coordinate system.
The calibration apparatus according to claim 11, wherein N is an integer greater than or equal to 4, and said apparatus further comprises an error calculation unit for performing at least one of said three sets of homogeneous matrices, O T and The remaining at least one set of rotation angles calculates an error of coordinate values of the tool coordinate system origin in the flange coordinate system.
The calibration apparatus according to claim 12, wherein the error calculation unit comprises:

a first sub-error calculating unit configured to calculate, by using a forward kinematics algorithm, at least one fourth set of homogeneous matrices of the corresponding flange coordinate system from the remaining at least one set of rotation angles, and expressed as:

Wherein R 4 is a 3×3 matrix, which is used to indicate the direction of the flange coordinate system when the tool coordinate system origin corresponding to the remaining at least one set of rotation angles reaches the reference point; O 4 is 3× a matrix of 1 for indicating coordinates of an origin of the flange coordinate system when the tool coordinate system origin corresponding to the remaining at least one set of rotation angles reaches the reference point;

a second sub-error calculating unit, configured to calculate coordinates of an origin of the tool coordinate system in the flange coordinate system according to at least one of the three sets of homogeneous matrices, O T and the fourth set of homogeneous matrices The error of the value.
The calibration apparatus according to claim 13, wherein the second sub-error calculation unit calculates an error of a coordinate value of the tool coordinate system origin in the flange coordinate system by using the following formula:

T n =R n O T +O n

T 4 =R 4 O T +O 4

Err=|T n -T 4 |

Wherein R n and O n are respectively any one of R 1 , R 2 and R 3 and a corresponding one of O 1 , O 2 and O 3 in the three sets of homogeneous matrices, and err represents an error value.
A calibration device for an origin coordinate of a tool coordinate system of an industrial robot, characterized in that the calibration device comprises a processor and a memory connected to the processor, wherein the processor executes by executing a program stored in the memory The following steps:

Controlling the robot to drive the tool to be calibrated installed at the end of the robot, so that the origin of the tool coordinate system of the tool to be calibrated reaches a fixed reference point along N different trajectories, wherein the origin of the tool coordinate system arrives along different trajectories In the reference point, the origin of the flange coordinate system origin of the robot does not coincide with the line connecting the origin of the tool coordinate system, and N is an integer greater than or equal to 3;

Recording, respectively, a rotation angle of each axis of the robot each time the origin of the tool coordinate system reaches the reference point;

The coordinate values of the tool coordinate system origin in the flange coordinate system of the robot are calculated according to the recorded N sets of rotation angles.
The calibration device according to claim 15, wherein the step of calculating the coordinate value of the tool coordinate system origin in the flange coordinate system of the robot according to the recorded N sets of rotation angles comprises:

Three groups are randomly selected from the recorded N sets of rotation angles, and three corresponding homogeneous matrices of the flange coordinate system are calculated;

The coordinate values of the origin of the tool coordinate system in the flange coordinate system are calculated by the three sets of homogeneous matrices.
The calibration device according to claim 16, wherein the step of arbitrarily selecting three groups from the recorded N sets of rotation angles, and calculating the corresponding three sets of homogeneous matrices of the flange coordinate system comprises:

Using the forward kinematics algorithm, the three sets of homogeneous matrices of the corresponding flange coordinate system are respectively calculated from the selected three sets of rotation angles, which are respectively expressed as:

as well as

Wherein R 1 , R 2 and R 3 are respectively a matrix of 3×3 for respectively representing the flange coordinate system when the origin of the tool coordinate system corresponding to the three sets of rotation angles reaches the reference point The directions, O 1 , O 2 and O 3 are respectively 3×1 matrices for respectively representing the flange coordinates when the origin of the tool coordinate system corresponding to the three sets of rotation angles reaches the reference point The coordinates of the origin.
The calibration apparatus according to claim 16, wherein the step of calculating the coordinate values of the tool coordinate system origin in the flange coordinate system by the three sets of homogeneous matrices comprises:

Calculating the coordinate values of the origin of the tool coordinate system in the flange coordinate system by using the following formula:

O T =(R 1 +R 3 -2R 2 ) -1 (2O 2 -O 1 -O 3 ) (2)

Wherein, O T is a matrix of 3×1 for indicating the coordinate value of the origin of the tool coordinate system in the flange coordinate system.
The calibration apparatus according to claim 18, wherein N is an integer greater than or equal to 4, and said processor further performs the following steps:

Calculating an error of a coordinate value of the tool coordinate system origin in the flange coordinate system according to at least one of the three sets of homogeneous matrices, O T and the remaining at least one set of rotation angles.
The calibration apparatus according to claim 19, wherein said homogeneous according to the three sets of at least one matrix, O T and at least a set of the remaining rotation angle is calculated in the origin of the tool coordinate system the method The steps of the error of the coordinate values in the blue coordinate system include:

Calculating, by using a positive kinematics algorithm, at least one fourth set of homogeneous matrices of the corresponding flange coordinate system from the remaining at least one set of rotation angles, and expressing:

Wherein R 4 is a 3×3 matrix, which is used to indicate the direction of the flange coordinate system when the tool coordinate system origin corresponding to the remaining at least one set of rotation angles reaches the reference point; O 4 is 3× a matrix of 1 for indicating coordinates of an origin of the flange coordinate system when the tool coordinate system origin corresponding to the remaining at least one set of rotation angles reaches the reference point;

Calculating the error of the coordinate value of the origin of the tool coordinate system in the flange coordinate system by using the following formula:

T n =R n O T +O n

T 4 =R 4 O T +O 4

Err=|T n -T 4 |

Wherein R n and O n are respectively any one of R 1 , R 2 and R 3 and a corresponding one of O 1 , O 2 and O 3 in the three sets of homogeneous matrices, and err represents an error value.