Calibration method, calibration equipment and computer readable storage medium

Abstract

The invention discloses a calibration method, calibration equipment and a computer readable storage medium, and the method comprises the steps: controlling a first tool center point to make contact with a target tip point, and recording a first pose matrix of a flange coordinate system under a base coordinate system during contact; acquiring a second pose matrix of the flange coordinate system under the base coordinate system when the second tool center point is in contact with the target tip point; obtaining a first target pose matrix of the second tool center point under the flange coordinate system, and obtaining a first pose matrix and a first position matrix of the second tool center point under the flange coordinate system according to the first target pose matrix; and obtaining a second position matrix of the first tool center point under the flange coordinate system according to the inverse matrix of the first pose matrix, the second pose matrix and the first position matrix. According to the method, the position of the first tool center point can be quickly determined.

Description

Technical Field

[0001] The present application relates to the field of robotics technology, and in particular to a calibration method, a calibration device, and a computer-readable storage medium. Background Art

[0002] At present, the calibration of the tool center point (TCP point) of industrial robots is usually achieved by the four-point method. The specific operation is: fix a tip point in the robot workspace, determine a working point at the end of the robot tool as the center point of the tool (i.e., TCP point), operate the robot in four different postures to make the TCP point contact the tip point, and complete the calibration of the TCP point. However, this method requires the operator to ensure the precise alignment of the points, but it is impossible to observe whether the points are aligned from a single direction in space. At this time, the operator needs to observe the working point and the tip point from different directions during the calibration process, resulting in low calibration efficiency. In addition, if one point is not aligned during this process, the calibration accuracy will be poor. In view of this, how to quickly and accurately calibrate the TCP point of the tool has become an urgent problem to be solved. Summary of the invention

[0003] The present application provides a calibration method, a calibration device and a computer-readable storage medium, which can quickly determine the position matrix of a first tool center point in a flange coordinate system.

[0004] A first aspect of an embodiment of the present application provides a calibration method, which includes: controlling a first tool center point on a first tool mounted on an end of a robot to contact a target tip point, and recording a first pose matrix of the flange coordinate system of the robot in the base coordinate system of the robot when the contact occurs, wherein the target tip point is fixed in the working space of the robot; obtaining a second pose matrix of the flange coordinate system in the base coordinate system of the robot when a second tool center point on a second tool mounted on the end of the robot contacts the target tip point; obtaining a first target pose matrix of the second tool center point in the flange coordinate system obtained by calibrating the second tool, and obtaining a first pose matrix and a first position matrix of the second tool center point in the flange coordinate system based on the first target pose matrix; obtaining a second position matrix of the first tool center point in the flange coordinate system based on the inverse matrix of the first pose matrix, the second pose matrix and the first position matrix.

[0005] According to a second aspect of an embodiment of the present application, there is provided a calibration device, which comprises: a control module, which is used to control the first tool center point on the first tool mounted on the end of the robot to contact with the target tip point, and record the first pose matrix of the flange coordinate system of the robot in the base coordinate system of the robot when the contact occurs, wherein the target tip point is fixed in the working space of the robot; a first acquisition module, which is used to acquire the second pose matrix of the flange coordinate system in the base coordinate system of the robot when the second tool center point on the second tool mounted on the end of the robot contacts with the target tip point; a second acquisition module, which is used to acquire the first target pose matrix of the second tool center point in the flange coordinate system obtained by calibrating the second tool, and to acquire the first pose matrix and the first position matrix of the second tool center point in the flange coordinate system according to the first target pose matrix; a calibration module, which is connected to the control module, the first acquisition module and the second acquisition module, and is used to acquire the second position matrix of the first tool center point in the flange coordinate system according to the inverse matrix of the first pose matrix, the second pose matrix and the first position matrix.

[0006] A third aspect of an embodiment of the present application provides a calibration device, which includes a processor, a memory, and a communication circuit. The processor is coupled to the memory and the communication circuit, respectively. The memory stores program data. The processor implements the steps in the above method by executing the program data in the memory.

[0007] A fourth aspect of an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program can be executed by a processor to implement the steps in the above method.

[0008] The beneficial effect is: the calibration method of the present application utilizes the property that the position of the target tip point remains unchanged during the calibration process to determine the second position matrix of the first tool center point in the flange coordinate system, and in the process of calibrating the first tool center point, the first tool center point only needs to contact the target tip point once, which is simple to operate, can save calibration time and improve calibration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0010] Figure 1It is a flow chart of an implementation method of the calibration method of the present application;

[0011] Figure 2 It is a structural schematic diagram of an implementation method of a calibration device of the present application;

[0012] Figure 3 It is a structural schematic diagram of another implementation method of the calibration device of the present application;

[0013] Figure 4 It is a structural schematic diagram of an implementation method of a computer-readable storage medium of the present application. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0015] It should be noted that the terms "first" and "second" in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0016] See also Figure 1 , Figure 1 : is a flow chart of an implementation method of the present application, the calibration method comprising:

[0017] S110: Control the first tool center point on the first tool installed at the end of the robot to contact the target tip point, and record the first position matrix of the flange coordinate system of the robot in the base coordinate system of the robot when in contact, wherein the target tip point is fixed in the working space of the robot.

[0018] Specifically, a tip point (that is, the target tip point) is fixed in the robot's working space in advance, and the position of the tip point remains unchanged during the entire subsequent calibration process. That is to say, at any time during the calibration process, the position of the target tip point in the robot's base coordinate system is always the same.

[0019] The first tool center point on the first tool is the target TCP point to be calibrated. After the first tool is installed on the end flange of the robot, a working point is determined on the first tool as the first tool center point, and then the robot is controlled so that the first tool center point contacts the target tip point, and when the first tool center point contacts the target tip point, the pose matrix of the robot's flange coordinate system in the robot base coordinate system (that is, the pose matrix of the robot's end flange in the robot base coordinate system) is recorded, and the pose matrix is ​​defined as the first pose matrix T new .

[0020] S120: Obtain a second pose matrix of the flange coordinate system in the base coordinate system of the robot when the center point of the second tool on the second tool installed at the end of the robot contacts the target tip point.

[0021] Specifically, before the first tool is installed on the end flange of the robot, the second tool is installed on the end flange, and the tool center point on the second tool is defined as the second tool center point. When the second tool is installed on the end of the robot, the robot is controlled so that the second tool center point on the second tool contacts the target tip point, and when the second tool center point contacts the target tip point, the pose matrix of the robot's flange coordinate system in the robot base coordinate system is recorded, and the pose matrix is ​​defined as the second pose matrix T old .

[0022] S130: Acquire a first target pose matrix of the center point of the second tool in the flange coordinate system obtained by calibrating the second tool, and obtain a first posture matrix and a first position matrix of the center point of the second tool in the flange coordinate system based on the first target pose matrix.

[0023] Specifically, when the second tool is installed on the end flange, the center point of the second tool is also calibrated to obtain the pose of the center point of the second tool in the flange coordinate system, that is, the first target pose matrix T Tool .

[0024] The first target pose matrix T Tool By dividing into blocks, we can get:

[0025]

[0026] Among them, R Toolis the posture matrix of the second tool center point in the flange coordinate system, which is defined as the first posture matrix here, P Tool is the position matrix of the second tool center point in the flange coordinate system, which is defined here as the first position matrix.

[0027] S140: Obtain a second position matrix of the first tool center point in the flange coordinate system according to the inverse matrix of the first pose matrix, the second pose matrix, and the first position matrix.

[0028] It can be understood that the position is represented by three-dimensional XYZ coordinates, and the first position matrix P Tool It can be represented as a matrix with three rows and one column.

[0029] At the same time, before calibrating the first tool center point, the second tool center point has been calibrated in advance, and the first target pose matrix T of the second tool center point is obtained. Tool .

[0030] because Therefore, the first posture matrix R of the second tool center point in the flange coordinate system can be obtained. Tool , the first position matrix P of the second tool center point in the flange coordinate system Tool .

[0031] At the same time, the second tool center point is controlled to contact the target tip point, and the second posture matrix T of the flange coordinate system in the base coordinate system of the robot is obtained when the second tool center point contacts the target tip point. old .

[0032] At the same time, due to Therefore, we can also get the posture matrix R of the flange coordinate system in the robot's base coordinate system when the second tool center point contacts the target tip point: old And the position matrix P old .

[0033] According to the second pose matrix T of the flange coordinate system in the base coordinate system of the robot when the second tool center point contacts the target tip point, old And the first target pose matrix T of the second tool center point Tool , we can get the pose matrix T of the second tool center point in the base coordinate system when the second tool center point contacts the target tip point E , the specific calculation formula is as follows:

[0034]

[0035] For the sake of convenience, the above formula is recorded as Formula 1, R Eis the posture matrix of the second tool center point in the base coordinate system when the second tool center point contacts the target tip point, P E It is the position matrix of the second tool center point in the base coordinate system when the second tool center point contacts the target tip point.

[0036] It can be understood that when the second tool center point contacts the target tip point, the second tool center point and the target tip point are the same point. Therefore, when the second tool center point contacts the target tip point, the position matrix P of the second tool center point in the base coordinate system is E It is also the position matrix of the target tip point in the base coordinate system when the second tool center point contacts the target tip point, that is, the position matrix P E It is both the position matrix of the second tool center point in the base coordinate system when the second tool center point contacts the target tip point, and the position matrix of the target tip point in the base coordinate system when the second tool center point contacts the target tip point.

[0037] From the above formula 1, we can know that P E =R old ×P Tool +P old .

[0038] At the same time, if P Tool for According to the second pose matrix T old Construct the first intermediate matrix P M , so that the first intermediate matrix P M The number of rows and the second pose matrix T old The number of columns is equal, and the specific construction process is as follows: Tool The number of rows added on the basis of , and the value in the newly added row is 1, that is, adding row one, specifically, let the first intermediate matrix P M for At this time, the following equation exists:

[0039]

[0040] So we can get the equation:

[0041] Because P E It is also the position matrix of the target tip point in the base coordinate system when the second tool center point contacts the target tip point. Therefore, the following conclusions can be drawn:

[0042] When the second tool center point contacts the target tip point, the position matrix P of the target tip point in the base coordinate system E Add one (i.e. ) is equal to the second pose matrix T of the flange coordinate system in the robot's base coordinate system when the second tool center point contacts the target tip pointold With the first intermediate matrix P M The result of multiplication, where the first intermediate matrix P M It is based on the first position matrix P of the second tool center point in the flange coordinate system Tool To be constructed.

[0043] After replacing the second tool with the first tool, according to the above derivation process, we can also get the following conclusions:

[0044] When the first tool center point contacts the target tip point, the position matrix P of the target tip point in the base coordinate system F Add one (i.e. ) is equal to the first pose matrix T of the flange coordinate system in the robot's base coordinate system when the first tool center point contacts the target tip point. new With the second intermediate matrix P N The result of multiplication, that is, P F =T nww ×P N If the second position matrix of the first tool center point in the flange coordinate system is According to the first pose matrix T new Construct the second intermediate matrix P by the number of columns N , so that the second intermediate matrix P N The number of rows and the first pose matrix T new The number of columns is equal, and the specific construction process is as follows: T ′ ool The number of rows added on the basis of , and the value in the newly added row is 1, that is, adding row one, specifically, the second intermediate matrix That is, the second intermediate matrix P N The second position matrix P of the first tool center point in the flange coordinate system T ′ ool The relative relationship between the first intermediate matrix P M The first position matrix P of the second tool center point in the flange coordinate system Tool The relative relationship is the same.

[0045] Since the position of the target tip in the base coordinate system remains unchanged during the entire calibration process, P E =P F , and then T old ×P M =T new ×P N , and finally get:

[0046]

[0047] Therefore, according to the above formula, the first pose matrix T new , the second pose matrix T ild With the first position matrix P Tool Multiply them in sequence and finally get the second intermediate matrix P N After that, remove the second intermediate matrix P N Row 1 in , so we can get the second position matrix P T ′ ool .

[0048] From the above content, it can be seen that the present application utilizes the property that the position of the target tip point remains unchanged during the calibration process to determine the second position matrix of the first tool center point in the flange coordinate system, and in the process of performing the above calibration on the first tool center point, it is only necessary for the first tool center point to contact the target tip point once, which is simple to operate, can save calibration time and improve calibration efficiency.

[0049] In one embodiment, after step S140, the method further includes:

[0050] S150: Using the first posture matrix as the second posture matrix of the first tool center point in the flange coordinate system.

[0051] Specifically, the first posture matrix R of the second tool center point in the flange coordinate system is Tool The second posture matrix of the first tool center point in the flange coordinate system is determined, that is, the posture matrix of the first tool center point in the flange coordinate system is considered to be the same as the posture matrix of the second tool center point in the flange coordinate system.

[0052] S160: Obtain a second target posture matrix of the first tool center point in the flange coordinate system according to the second position matrix and the second posture matrix.

[0053] Specifically, the second target pose matrix T of the first tool center point in the flange coordinate system can be determined according to the following formula: Tool_new :

[0054]

[0055] Among them, R Tool is the first posture matrix of the second tool center point in the flange coordinate system, and is also the second posture matrix of the first tool center point in the flange coordinate system, P T ′ ool is the second position matrix of the first tool center point in the flange coordinate system.

[0056] In the above implementation, considering that the posture requirements for the tool center point are not strict in some application scenarios, as long as the position of the tool center point is accurate, in the above implementation, it is considered that the posture of the second tool center point in the flange coordinate system is the same as the posture of the first tool center point in the flange coordinate system. Therefore, according to the second position matrix and the second posture matrix, the position and posture matrix of the first tool center point in the flange coordinate system can be determined to complete the calibration of the first tool center point.

[0057] In one embodiment, considering that the posture requirement for the tool center point on the welding gun is not high when welding with the welding gun, in one embodiment, the first tool and the second tool are both welding guns.

[0058] In other embodiments, the first tool and the second tool may both be fixtures, or in other embodiments, the types of the first tool and the second tool may be different, for example, the first tool is a welding gun and the second tool is a fixture. In short, the present application does not limit the types of the first tool and the second tool.

[0059] In one embodiment, the second tool center point is calibrated in advance using a four-point method to obtain a first target pose matrix T of the second tool center point in the flange coordinate system. Tool , wherein, during the calibration process using the four-point method, the second tool center point is controlled to contact the target tip point at least four times in succession.

[0060] Specifically, the specific process of calibrating the second tool center point using the four-point method is: the operator controls the robot so that the second tool center point contacts the target tip point, and records the pose matrix of the robot's end flange in the base coordinate system when the second tool center point contacts the target tip point, that is, the pose matrix of the flange coordinate system in the base coordinate system, and then changes the robot's posture, controls the second tool center point to contact the target tip point again, and also records the pose matrix of the robot's end flange in the base coordinate system when the second tool center point contacts the target tip point, repeats the above steps, and controls the second tool center point to contact the target tip point at least four times in succession. Since the target tip point remains different during the calibration process, the position of the target tip point in the robot's base coordinate system is the same, so according to this constraint relationship, the pose matrix of the second tool center point in the robot's flange coordinate system can be calculated. Therefore, the first target pose matrix T of the second tool center point in the flange coordinate system can be obtained by the four-point calibration method. Tool .

[0061] Of course, in other implementations, other calibration methods may be used to pre-calibrate the second tool center point, and the present application does not limit the specific calibration method of the second tool center point.

[0062] It can be seen from the above calibration process that in the process of calibrating the second tool center point using the four-step method, the second tool center point will contact the target tip point at least four times in succession. Therefore, in one embodiment, in the process of calibrating the second tool center point using the four-point method, when the second tool center point contacts the target tip point, the second pose matrix T of the flange coordinate system in the base coordinate system is recorded. old For example, in the process of calibrating the second tool center point, the second tool center point contacts the target tip point four times in succession. Then, when the second tool center point contacts the target tip point for the first time, the second pose matrix T of the flange coordinate system in the base coordinate system can be recorded. old , or the second pose matrix T of the flange coordinate system in the base coordinate system can be recorded when the second tool center point contacts the target tip point for the second, third or fourth time. old Of course, in other implementations, the second posture matrix T may not be obtained during the calibration of the second tool center point. old , but before or after the second tool center point is calibrated, when the second tool center point is controlled to contact the target tip point, the second pose matrix T of the flange coordinate system in the base coordinate system is recorded at this time old .

[0063] See also Figure 2 , Figure 2 It is a structural diagram of an embodiment of the calibration device of the present application. The calibration device 200 includes a processor 210, a memory 220 and a communication circuit 230. The processor 210 is coupled to the memory 220 and the communication circuit 230 respectively. The memory 220 stores program data. The processor 210 implements the steps in any of the above-mentioned implementation methods by executing the program data in the memory 220. The detailed steps can be found in the above-mentioned implementation, which will not be repeated here.

[0064] The calibration device 200 may be any device with algorithm processing capability, such as a mobile phone, a robot control cabinet, etc., and is not limited here.

[0065] See also Figure 3 , Figure 3 The calibration device 300 includes a control module 310 , a first acquisition module 320 , a second acquisition module 330 and a calibration module 340 .

[0066] The control module 310 is used to control the contact between the first tool center point on the first tool installed at the end of the robot and the target tip point, and record the first pose matrix of the robot's flange coordinate system in the robot's base coordinate system when in contact, wherein the target tip point is fixed in the robot's workspace.

[0067] The first acquisition module 320 is used to acquire a second pose matrix of the flange coordinate system in the base coordinate system of the robot when the second tool center point on the second tool installed at the end of the robot contacts the target tip point.

[0068] The second acquisition module 330 is used to obtain the first target pose matrix of the second tool center point in the flange coordinate system obtained by calibrating the second tool, and obtain the first posture matrix and the first position matrix of the second tool center point in the flange coordinate system based on the first target pose matrix.

[0069] The calibration module 340 is connected to the control module 310, the first acquisition module 320 and the second acquisition module 330, and is used to obtain the second position matrix of the first tool center point in the flange coordinate system according to the inverse matrix of the first pose matrix, the second pose matrix and the first position matrix.

[0070] In one embodiment, the calibration module 340 is also used to: use the first posture matrix as the second posture matrix of the first tool center point in the flange coordinate system; and obtain the second target posture matrix of the first tool center point in the flange coordinate system based on the second position matrix and the second posture matrix.

[0071] In one embodiment, the calibration module 340 is also used to: pre-calibrate the second tool center point using the four-point method to obtain a first target pose matrix of the second tool center point in the flange coordinate system, wherein, during the calibration process using the four-point method, the second tool center point is controlled to contact the target tip point at least four times in succession.

[0072] The calibration device 300 may be any device with algorithm processing capability, such as a mobile phone or a robot control cabinet, and is not limited here.

[0073] Among them, the calibration device 300 executes the method steps in any of the above-mentioned implementation modes when working. The detailed steps can be found in the above-mentioned implementation modes and will not be repeated here.

[0074] See also Figure 4 , Figure 4 The computer-readable storage medium 400 stores a computer program 410, which can be executed by a processor to implement the steps in any of the above methods.

[0075] Among them, the computer-readable storage medium 400 can specifically be a device that can store the computer program 410, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, or it can also be a server that stores the computer program 410. The server can send the stored computer program 410 to other devices for execution, or it can also run the stored computer program 410 by itself.

[0076] The above description is only an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A calibration method, characterized in that: The method comprises: Controlling a first tool center point on a first tool mounted at the end of the robot to contact with a target tip point, and recording a first pose matrix of a flange coordinate system of the robot in a base coordinate system of the robot when contacting, wherein the target tip point is fixed in a working space of the robot; Acquire a second pose matrix of the flange coordinate system in the base coordinate system of the robot when a second tool center point on a second tool mounted on the end of the robot contacts the target tip point; Acquire a first target pose matrix of the center point of the second tool in the flange coordinate system obtained by calibrating the second tool, and obtain a first posture matrix and a first position matrix of the center point of the second tool in the flange coordinate system according to the first target pose matrix; A second position matrix of the first tool center point in the flange coordinate system is obtained according to the inverse matrix of the first posture matrix, the second posture matrix and the first position matrix.

2. The method according to claim 1, characterized in that The method further comprises: Using the first posture matrix as the second posture matrix of the first tool center point in the flange coordinate system; A second target posture matrix of the first tool center point in the flange coordinate system is obtained according to the second position matrix and the second posture matrix.

3. The method according to claim 1, characterized in that The first tool and the second tool are both welding guns.

4. The method according to claim 1, characterized in that: The method further comprises: The second tool center point is calibrated in advance using the four-point method to obtain the first target pose matrix of the second tool center point in the flange coordinate system, wherein, during the calibration process using the four-point method, the second tool center point is controlled to contact the target tip point at least four times in succession.

5. The method according to claim 4, characterized in that The method further comprises: In the process of calibrating the second tool center point by using the four-point method, when the second tool center point contacts the target tip point, the second pose matrix of the flange coordinate system in the base coordinate system is recorded.

6. A calibration device, characterized in that: The calibration equipment comprises: a control module, configured to control a first tool center point on a first tool mounted at the end of the robot to contact with a target tip point, and record a first pose matrix of a flange coordinate system of the robot in a base coordinate system of the robot when contact is made, wherein the target tip point is fixed in a working space of the robot; A first acquisition module is used to acquire a second pose matrix of the flange coordinate system in the base coordinate system of the robot when a second tool center point on a second tool mounted on the end of the robot contacts the target tip point; A second acquisition module is used to acquire a first target pose matrix of the center point of the second tool in the flange coordinate system obtained by calibrating the second tool, and obtain a first posture matrix and a first position matrix of the center point of the second tool in the flange coordinate system according to the first target pose matrix; A calibration module is connected to the control module, the first acquisition module and the second acquisition module, and is used to obtain a second position matrix of the first tool center point in the flange coordinate system according to the inverse matrix of the first posture matrix, the second posture matrix and the first position matrix.

7. The calibration device according to claim 6, characterized in that: The calibration module is also used to: use the first posture matrix as the second posture matrix of the first tool center point in the flange coordinate system; and obtain a second target posture matrix of the first tool center point in the flange coordinate system based on the second position matrix and the second posture matrix.

8. The calibration device according to claim 6, characterized in that: The calibration module is used to: pre-calibrate the second tool center point using the four-point method to obtain the first target pose matrix of the second tool center point in the flange coordinate system, wherein, during the calibration process using the four-point method, the second tool center point is controlled to contact the target tip point at least four times in succession.

9. A calibration device, characterized in that: The calibration device includes a processor, a memory and a communication circuit, the processor is coupled to the memory and the communication circuit respectively, the memory stores program data, and the processor implements the steps in the method as described in any one of claims 1 to 5 by executing the program data in the memory.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program can be executed by a processor to implement the steps in the method according to any one of claims 1 to 5.

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