Robot external actuator calibration method, device and equipment

Abstract

The invention discloses a calibration method, device and equipment for an external actuator of a robot, and the method comprises the steps: enabling the tail end of a mechanical arm with a calibration plate to be in contact with the actuator in different poses, and obtaining two different circular mark points and a preset transformation matrix; calculating a three-dimensional point cloud coordinate of the circular mark point based on a mapping relation between a pixel coordinate and a point cloud coordinate in the structured light system; calculating a pose transformation matrix between two poses at the tail end of the mechanical arm according to a preset transformation matrix; according to the three-dimensional point cloud coordinates, the pose transformation matrix and a preset hand-eye matrix, the actuator coordinates of the tail end of the actuator under the mechanical arm base coordinate system are calculated; direction vectors of the tail ends of the actuators are calculated through the coordinates of the two different actuators; and calculating a homogeneous transformation matrix calibrated and aligned at the tail end of the actuator according to the direction vector to obtain a calibration result. The technical problem that the actual calibration scene requirement is difficult to meet due to the problems of low precision, complex measurement process, high cost and the like in the prior art can be solved.

Description

Technical Field

[0001] The present application relates to the field of robot control technology, and in particular to a robot external actuator calibration method, device and equipment. Background Art

[0002] In the fields of electronic manufacturing and aviation industry, robots are often used to assemble electronic products and assemble screws on wing skins. The robot's operating actuator is often located at the end of the robot arm. Compared with this type of actuator, the actuator located outside the robot is more adaptable to flexible assembly systems; the latter can adapt to holes of different sizes and postures during assembly operations; it has the advantages of flexible operation, no reliance on teaching operations, and a wide range of applicable workpieces. However, when using this type of actuator located outside the robot for assembly operations, it is difficult to determine the posture transformation relationship of the external actuator relative to the robot arm base coordinate system.

[0003] Existing methods mainly include visual tracking and laser interferometer measurement. Among them, the visual tracking method has low measurement accuracy. Although the laser interferometer has high measurement accuracy, its measurement degree of freedom is single, the operation process is complicated, the equipment cost is high and it is sensitive to environmental disturbances. Therefore, it is difficult to meet the calibration operation requirements in various scenarios. Summary of the invention

[0004] The present application provides a robot external actuator calibration method, device and equipment, which are used to solve the technical problems of low accuracy, complex measurement process and high cost in the prior art, which make it difficult to meet the needs of actual calibration scenarios.

[0005] In view of this, the first aspect of the present application provides a robot external actuator calibration method, comprising:

[0006] The end of the robot arm with the calibration plate contacts the actuator in different postures to obtain two different circular marking points and the corresponding preset transformation matrix from the base of the robot arm to the end;

[0007] Based on the mapping relationship between the pixel coordinates and the point cloud coordinates in the structured light system, the three-dimensional point cloud coordinates of the two circular marking points are calculated respectively;

[0008] Calculating the transformation matrix between the two postures of the end of the robotic arm according to the preset transformation matrix to obtain a posture transformation matrix;

[0009] Calculate the position of the actuator end in the robot arm base coordinate system according to the three-dimensional point cloud coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates;

[0010] Calculating the direction vector of the actuator end in the robot arm base coordinate system through two different actuator coordinates;

[0011] A homogeneous transformation matrix for calibration and alignment of the actuator end is calculated according to the direction vector to obtain a calibration result.

[0012] Preferably, the end of the robot arm with the calibration plate contacts the actuator in different postures to obtain two different circular marking points and a corresponding preset transformation matrix from the base of the robot arm to the end, and the method also includes:

[0013] The calibration plate is fixedly set at the end of the robotic arm, the posture of the robotic arm end is adjusted multiple times, and multiple images are taken and the posture of the robotic arm end is recorded to obtain the posture of the robotic arm end;

[0014] Determine the mapping relationship between pixel coordinates and point cloud coordinates based on the intrinsic parameter matrix of the camera and projector of the structured light system;

[0015] The matrix from the camera coordinate system to the robot arm base coordinate system is calibrated according to the robot arm end posture and the intrinsic parameter matrix to obtain a preset hand-eye matrix.

[0016] Preferably, the three-dimensional point cloud coordinates of the two circular marking points are calculated based on the mapping relationship between the pixel coordinates and the point cloud coordinates in the structured light system, including:

[0017] Move the two circular marking points of the calibration plate into the field of view of the structured light system, and capture images of the marking points;

[0018] Perform a circle center mark fitting operation according to the mark point image to obtain the circle center pixel coordinates;

[0019] The point cloud coordinates corresponding to the circle center pixel coordinates are calculated based on the mapping relationship between the pixel coordinates and the point cloud coordinates to obtain the three-dimensional point cloud coordinates of the circular marking point.

[0020] Preferably, the calculating the position of the actuator end in the robot arm base coordinate system according to the three-dimensional point cloud coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates includes:

[0021] Calculating point cloud homogeneous coordinates according to the three-dimensional point cloud coordinates;

[0022] The position of the actuator end in the robot arm base coordinate system is calculated according to the point cloud homogeneous coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates.

[0023] Preferably, the step of calculating a homogeneous transformation matrix for calibration and alignment of the actuator end according to the direction vector to obtain a calibration result includes:

[0024] The rotation axis vector is obtained by performing a vector cross product calculation based on the normalized direction vector and the normal vector of any point in the robot base coordinate system;

[0025] Constructing a rotation matrix according to the rotation axis vector and the vector angle, wherein the vector angle is the angle between the direction vector and the normal vector of the arbitrary point;

[0026] A homogeneous transformation matrix for calibration and alignment of the actuator end is calculated according to the rotation matrix and the preset translation vector to obtain a calibration result.

[0027] Preferably, the step of calculating a homogeneous transformation matrix for calibration and alignment of the actuator end according to the rotation matrix and the preset translation vector to obtain a calibration result further includes:

[0028] The actuator coordinates calculated for the first time are used as the pose homogeneous coordinates of the current circular mark point when the end of the robot arm is in the first pose state;

[0029] The preset translation vector is constructed according to the pose homogeneous coordinates and the coordinates of the arbitrary point.

[0030] A second aspect of the present application provides a robot external actuator calibration device, comprising:

[0031] A posture marking unit is used to contact the actuator with different postures through the end of the robot arm with a calibration plate to obtain two different circular marking points and the corresponding preset transformation matrix from the base of the robot arm to the end;

[0032] A coordinate calculation unit, used to calculate the three-dimensional point cloud coordinates of the two circular marking points respectively based on the mapping relationship between the pixel coordinates and the point cloud coordinates in the structured light system;

[0033] A matrix transformation unit, used for calculating the transformation matrix between the two postures of the end of the robot arm according to the preset transformation matrix to obtain a posture transformation matrix;

[0034] An end positioning unit is used to calculate the position of the actuator end in the robot arm base coordinate system according to the three-dimensional point cloud coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates;

[0035] A vector calculation unit, used for calculating the direction vector of the actuator end in the robot arm base coordinate system through two different actuator coordinates;

[0036] A homogeneous calibration unit is used to calculate a homogeneous transformation matrix for calibration alignment of the actuator end according to the direction vector to obtain a calibration result.

[0037] Preferably, the coordinate calculation unit is specifically used for:

[0038] Move the two circular marking points of the calibration plate into the field of view of the structured light system, and capture images of the marking points;

[0039] Perform a circle center mark fitting operation according to the mark point image to obtain the circle center pixel coordinates;

[0040] The point cloud coordinates corresponding to the circle center pixel coordinates are calculated based on the mapping relationship between the pixel coordinates and the point cloud coordinates to obtain the three-dimensional point cloud coordinates of the circular marking point.

[0041] Preferably, the homogeneous calibration unit is specifically used for:

[0042] The rotation axis vector is obtained by performing a vector cross product calculation based on the normalized direction vector and the normal vector of any point in the robot base coordinate system;

[0043] Constructing a rotation matrix according to the rotation axis vector and the vector angle, wherein the vector angle is the angle between the direction vector and the normal vector of the arbitrary point;

[0044] A homogeneous transformation matrix for calibration and alignment of the actuator end is calculated according to the rotation matrix and the preset translation vector to obtain a calibration result.

[0045] A third aspect of the present application provides a robot external actuator calibration device, the device comprising a processor and a memory;

[0046] The memory is used to store program code and transmit the program code to the processor;

[0047] The processor is used to execute the robot external actuator calibration method described in the first aspect according to the instructions in the program code.

[0048] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0049] In the present application, a method for calibrating an external actuator of a robot is provided, including: contacting the actuator with the end of a robotic arm with a calibration plate in different postures to obtain two different circular marking points and a corresponding preset transformation matrix from the base of the robotic arm to the end; calculating the three-dimensional point cloud coordinates of the two circular marking points based on the mapping relationship between the pixel coordinates and the point cloud coordinates in the structured light system; calculating the transformation matrix between the two postures of the end of the robotic arm according to the preset transformation matrix to obtain the posture transformation matrix; calculating the position of the actuator end in the robotic arm base coordinate system according to the three-dimensional point cloud coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates; calculating the direction vector of the actuator end in the robotic arm base coordinate system through two different actuator coordinates; calculating the homogeneous transformation matrix of the calibration alignment of the actuator end according to the direction vector to obtain the calibration result.

[0050] The robot external actuator calibration method provided by the present application configures a calibration plate at the end of the robotic arm, and solves the posture information of the actuator end based on the marking points obtained by two contacts. This operation can eliminate the influence caused by the repeated positioning error of the robotic arm; and the three-dimensional point cloud coordinates of the marking points solved by the structured light system have higher accuracy in the Z-axis direction; thereafter, the homogeneous transformation matrix of the calibration result is determined by specific matrix, vector and other calculation methods, which does not rely on complex operation processes and can ensure the accuracy of the calculation results; the actual operation action is only to take points at different postures of the calibration plate, which can meet the calibration requirements of multiple postures and does not involve high cost investment. Therefore, the present application can solve the technical problems of low accuracy, complex measurement process and high cost in the prior art, which make it difficult to meet the actual calibration scene requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of a flow chart of a robot external actuator calibration method provided in an embodiment of the present application;

[0052] Figure 2 A schematic diagram of the structure of a robot external actuator calibration device provided in an embodiment of the present application;

[0053] Figure 3 A schematic diagram of the overall structure of a robot external actuator calibration device provided in an embodiment of the present application;

[0054] Figure 4 A schematic diagram of the relationship between the circular marking points left on the calibration plate by the actuator provided in an embodiment of the present application and the corner points of the calibration plate;

[0055] Figure 5 Schematic diagram of circular marking points on the calibration plate provided in an embodiment of the present application. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings 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.

[0057] For easier understanding, see Figure 1 , an embodiment of a robot external actuator calibration method provided by the present application includes:

[0058] Step 101: The end of the robot arm with a calibration plate contacts the actuator in different postures to obtain two different circular marking points and corresponding preset transformation matrices from the base of the robot arm to the end.

[0059] Furthermore, step 101, before that, also includes:

[0060] The calibration plate is fixedly set at the end of the robot arm, the posture of the end of the robot arm is adjusted multiple times, and multiple images are taken and the posture of the end of the robot arm is recorded to obtain the posture of the end of the robot arm;

[0061] Determine the mapping relationship between pixel coordinates and point cloud coordinates based on the intrinsic parameter matrix of the camera and projector of the structured light system;

[0062] The matrix from the camera coordinate system to the robot base coordinate system is calibrated according to the end pose of the robot arm and the intrinsic parameter matrix to obtain the preset hand-eye matrix.

[0063] Please note that Figure 3 The device of this embodiment includes a calibration plate, a structured light scanner, a robotic arm, and an external actuator. After the calibration plate is set at the end of the robotic arm, the posture of the robotic arm end can be adjusted multiple times to take photos in different postures, obtain the captured images and record the posture of the robotic arm end at the corresponding time, and obtain the posture of the robotic arm end, which is recorded as .

[0064] After the camera and projector inside the structured light scanner in the structured light system are calibrated by the calibration plate set at the end of the robotic arm, their intrinsic parameter matrices are obtained. The intrinsic parameter matrices of the camera and projector can be expressed as and , specifically expressed as:

[0065]

[0066]

[0067] in, , , , are the focal lengths of the camera and projector on the x-axis and y-axis respectively, and their values ​​are the ratios of the actual focal lengths of the camera and projector to the pixel sizes on their sensors. , , , are the x- and y-axis coordinates of the intersection of the camera and projector optical axes with their image planes, respectively. , Respectively represent the non-orthogonality between the camera and projector coordinate axes. Ideally, , The value is 0. When the imaging planes of the two are not orthogonal, the value is not 0.

[0068] According to the end-arm position and intrinsic matrix, the preset hand-eye matrix of the camera coordinate system to the base coordinate system of the robot can be calibrated. Specifically, according to the multiple calibration plate images obtained above, the transformation relationship between the camera coordinate system and the origin coordinate system of the calibration plate mark point can be obtained. ; Through the transformation relationship between the origin coordinates of the calibration plate and the end of the robot arm Transformation relationship from the base of the robot to the end of the robot The system of equations can be constructed:

[0069]

[0070] in, To preset the hand-eye matrix, the equation is , where i is the number of calibration plate photos when calibrating the internal reference, which is generally between 25 and 40; the equation has and The invariance of; using the Kronecker product method to solve, we can get the preset hand-eye matrix :

[0071]

[0072] in, and They represent the rotation transformation relationship and translation transformation relationship from the camera coordinate system to the robot base coordinate system, where the robot base coordinate system is the world coordinate system; preset hand-eye matrix The size is , and represents a rigid body transformation with 6 degrees of freedom.

[0073] The preset transformation matrix from the base to the end of the robot arm is expressed as:

[0074]

[0075] in, and They respectively represent the transformation relationship from the robot base coordinate system to the robot end coordinate system. This embodiment requires operating the robot end twice, which can be recorded as posture 1 and posture 2. When the robot end with the calibration plate moves to posture 1, the actuator end with the color ink droplet will contact the calibration plate, thereby leaving a circular mark on the calibration plate. At the same time, the transformation matrix from the robot base to the end in posture 1 is also recorded, that is, the preset transformation matrix Similarly, the end-arm can be moved to position 2 again, and another circular marker point and the corresponding preset transformation matrix can also be determined. It should be noted that the posture 2 of this embodiment is within the field of view of the light scanner of the structured light system.

[0076] Step 102: Calculate the three-dimensional point cloud coordinates of two circular marking points based on the mapping relationship between pixel coordinates and point cloud coordinates in the structured light system.

[0077] Further, step 102 includes:

[0078] Move the two circular marking points on the calibration plate into the field of view of the structured light system and take images of the marking points;

[0079] Perform circle center mark fitting operation according to the mark point image to obtain the circle center pixel coordinates;

[0080] Based on the mapping relationship between pixel coordinates and point cloud coordinates, the point cloud coordinates corresponding to the pixel coordinates of the circle center are calculated to obtain the three-dimensional point cloud coordinates of the circular marking point.

[0081] The above operation can achieve different postures by moving the end of the manipulator and determine two different circular markers and the corresponding preset transformation matrix; please refer to Figure 4 and Figure 5 Then, the two circular marking points of the calibration plate can be moved to the field of view of the structured light system, and the marking point image can be captured; according to the geometric characteristics of the image, the center of the circle can be fitted on the marking point image to obtain the pixel coordinates of the center of the circle, which are recorded as , expressed as , which uses the origin of the calibration plate as the reference coordinate system and has a size of .

[0082] The mapping relationship between pixel coordinates and point cloud coordinates can be expressed as:

[0083]

[0084] That is, a mapping from a two-dimensional point set to a three-dimensional point set, where:

[0085]

[0086] This process uses the pixel coordinates of the center of the circle In three-dimensional point set Find the corresponding point cloud coordinates in , that is, the three-dimensional point cloud coordinate C, which is established in the camera coordinate system of the structured light system.

[0087] Step 103: Calculate the transformation matrix between the two postures of the end of the robot arm according to the preset transformation matrix to obtain the posture transformation matrix.

[0088] The two preset transformation matrices corresponding to the two circular marking points in this embodiment are respectively expressed as , According to these two preset transformation matrices, the posture transformation of the end of the robot arm from posture 1 to posture 2 can be calculated to obtain the posture transformation matrix , which can be specifically expressed as:

[0089]

[0090] Step 104: Calculate the position of the actuator end in the robot arm base coordinate system according to the three-dimensional point cloud coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates.

[0091] Furthermore, step 104 includes:

[0092] Calculate the homogeneous coordinates of the point cloud based on the coordinates of the three-dimensional point cloud;

[0093] The position of the actuator end in the robot arm base coordinate system is calculated according to the point cloud homogeneous coordinates, the pose transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates.

[0094] According to the above calculation, the three-dimensional point cloud coordinates C = Can calculate point cloud homogeneous coordinates , the specific process is expressed as:

[0095]

[0096] in, , , .

[0097] According to the homogeneous coordinates of the point cloud , pose transformation matrix and preset hand-eye matrix Calculate actuator coordinates The process is expressed as:

[0098]

[0099] in, is the first pose state, that is, the actuator coordinates calculated in the pose 1 state, so it is also recorded as the pose homogeneous coordinates .

[0100] By repeating the above operation of the end position of the robot arm, the position coordinates of another set of different circular markers in the robot arm base coordinate system can be calculated, that is, another actuator coordinate system Specifically, you only need to operate the end of the robot arm to contact the end of the actuator again, shoot the circular mark point, and record the mark point and preset transformation matrix in the state of posture 3 and posture 4. , , and then the specific actuator coordinates can be calculated according to the above method However, in this embodiment, it is required to avoid that the contact marks of the previous and the next two times are located at the same position, which leads to singularity in the equation, so the preset transformation matrix , The following conditions must be met:

[0101]

[0102]

[0103] And the dot product of the pose transformation matrix from pose 1 to pose 2 and the pose transformation matrix from pose 4 to pose 3 is the unit matrix, that is:

[0104]

[0105] in:

[0106]

[0107] in, is the pose transformation matrix of the end of the robot arm from pose 4 to pose 3, and its size is , and the actuator coordinates The coordinates in the robot base coordinate system can be expressed as:

[0108]

[0109] in:

[0110]

[0111] in, It represents the pose transformation matrix of the end of the robot arm from pose 1 to pose 3, and its size is , is the transformation matrix from the end of the robot to the base in the posture 1 state, and the transformation matrix from the base of the robot to the end in the posture 1 state are inverse matrices of each other.

[0112] Step 105: Calculate the direction vector of the actuator end in the robot arm base coordinate system through two different actuator coordinates.

[0113] According to the two different actuator coordinates obtained above , The direction vector m of the actuator end in the robot base coordinate system can be calculated. The specific process of determining the direction vector m is expressed as:

[0114]

[0115] Step 106: Calculate the homogeneous transformation matrix of the actuator end alignment according to the direction vector to obtain a calibration result.

[0116] Further, step 106 includes:

[0117] The rotation axis vector is obtained by performing a vector cross product calculation based on the normalized direction vector and the normal vector of any point in the robot base coordinate system;

[0118] Construct a rotation matrix based on the rotation axis vector and the vector angle, where the vector angle is the angle between the direction vector and the normal vector of any point;

[0119] The homogeneous transformation matrix for the calibration alignment of the actuator end is calculated according to the rotation matrix and the preset translation vector to obtain the calibration result.

[0120] Furthermore, the homogeneous transformation matrix of the actuator end calibration alignment is calculated according to the rotation matrix and the preset translation vector to obtain the calibration result, which also includes:

[0121] The actuator coordinates calculated for the first time are used as the pose homogeneous coordinates of the current circular mark point when the end of the robot arm is in the first pose state;

[0122] Construct a preset translation vector based on the pose homogeneous coordinates and the coordinates of any point.

[0123] It should be noted that after the direction vector m is calculated above, the direction vector m is normalized to obtain , the specific process is:

[0124]

[0125] in, , , They represent the components of the vector m on the three coordinate axes x, y, and z in the spatial rectangular coordinate system, where the modulus of the unnormalized direction vector m is:

[0126]

[0127] For any point in the robot base coordinate system, it can be expressed as , its normal vector can be written as Before calibration calculation, the pose homogeneous coordinates defined above are required. and the coordinates of any point Constructing a preset translation vector :

[0128]

[0129] According to the normalized direction vector and the normal vector of any point A rotation axis-rotation angle model can be constructed, where the rotation axis is the cross product of two vectors, and the rotation axis is recorded as the vector cross product vector a:

[0130]

[0131] Among them, a x 、a y 、a z They respectively represent the components of the rotation axis a on the three coordinate axes x, y, and z in the spatial rectangular coordinate system.

[0132] Corner is the angle between two vectors:

[0133]

[0134] Then the rotation matrix can be expressed as:

[0135]

[0136] in, is the identity matrix, is the antisymmetric matrix of the rotation axis a, expressed as:

[0137]

[0138] According to the rotation matrix and preset translation vector The homogeneous transformation matrix for the calibration alignment of the actuator end can be calculated :

[0139]

[0140] According to the obtained homogeneous transformation matrix Any point P located in the base coordinate system of the robot arm can be aligned to the end of the external actuator of the robot arm. Based on this principle, the end of the robot arm with any workpiece to be processed or assembled can be moved to the end of the actuator to complete the processing or assembly task.

[0141] The robot external actuator calibration method provided in the embodiment of the present application configures a calibration plate at the end of the robotic arm, and solves the posture information of the actuator end based on the marking points obtained by two contacts. This operation can eliminate the influence caused by the repeated positioning error of the robotic arm; and the three-dimensional point cloud coordinates of the marking points solved by the structured light system have higher accuracy in the Z-axis direction; thereafter, the homogeneous transformation matrix of the calibration result is determined by specific matrix, vector and other calculation methods, which does not rely on complex operation processes and can ensure the accuracy of the calculation results; the actual operation action is only to take points at different postures of the calibration plate, which can meet the calibration requirements of multiple postures and does not involve high cost investment. Therefore, the embodiment of the present application can solve the technical problems of low accuracy, complex measurement process and high cost in the prior art, which make it difficult to meet the actual calibration scene requirements.

[0142] For easier understanding, see Figure 2 , the present application provides an embodiment of a robot external actuator calibration device, comprising:

[0143] A posture marking unit 201 is used to contact the actuator with different postures through the end of the robot arm with a calibration plate to obtain two different circular marking points and a corresponding preset transformation matrix from the base of the robot arm to the end;

[0144] A coordinate calculation unit 202, used to calculate the three-dimensional point cloud coordinates of two circular marking points based on the mapping relationship between the pixel coordinates and the point cloud coordinates in the structured light system;

[0145] The matrix transformation unit 203 is used to calculate the transformation matrix between two postures of the end of the robot arm according to the preset transformation matrix to obtain the posture transformation matrix;

[0146] The end positioning unit 204 is used to calculate the position of the actuator end in the robot arm base coordinate system according to the three-dimensional point cloud coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates;

[0147] A vector calculation unit 205, used to calculate the direction vector of the actuator end in the robot arm base coordinate system through two different actuator coordinates;

[0148] The homogeneous calibration unit 206 is used to calculate the homogeneous transformation matrix for calibration alignment of the actuator end according to the direction vector to obtain a calibration result.

[0149] Further, the coordinate calculation unit 202 is specifically used for:

[0150] Move the two circular marking points on the calibration plate into the field of view of the structured light system and take images of the marking points;

[0151] Perform circle center mark fitting operation according to the mark point image to obtain the circle center pixel coordinates;

[0152] Based on the mapping relationship between pixel coordinates and point cloud coordinates, the point cloud coordinates corresponding to the pixel coordinates of the circle center are calculated to obtain the three-dimensional point cloud coordinates of the circular marking point.

[0153] Further, the homogeneous calibration unit 206 is specifically used for:

[0154] The rotation axis vector is obtained by performing a vector cross product calculation based on the normalized direction vector and the normal vector of any point in the robot base coordinate system;

[0155] Construct a rotation matrix based on the rotation axis vector and the vector angle, where the vector angle is the angle between the direction vector and the normal vector of any point;

[0156] The homogeneous transformation matrix for the calibration alignment of the actuator end is calculated according to the rotation matrix and the preset translation vector to obtain the calibration result.

[0157] The present application also provides a robot external actuator calibration device, the device comprising a processor and a memory;

[0158] The memory is used to store the program code and transmit the program code to the processor;

[0159] The processor is used to execute the robot external actuator calibration method in the above method embodiment according to the instructions in the program code.

[0160] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0161] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0162] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0163] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a number of instructions for executing all or part of the steps of the method described in each embodiment of the present application through a computer device (which can be a personal computer, server, or network device, etc.). The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk and other media that can store program codes.

[0164] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A robot external actuator calibration method, characterized in that: include: The end of the robot arm with the calibration plate contacts the actuator in different postures to obtain two different circular marking points and the corresponding preset transformation matrix from the base of the robot arm to the end; Based on the mapping relationship between the pixel coordinates and the point cloud coordinates in the structured light system, the three-dimensional point cloud coordinates of the two circular marking points are calculated respectively; Calculating the transformation matrix between the two postures of the end of the robotic arm according to the preset transformation matrix to obtain a posture transformation matrix; Calculate the position of the actuator end in the robot arm base coordinate system according to the three-dimensional point cloud coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates; Calculating the direction vector of the actuator end in the robot arm base coordinate system through two different actuator coordinates; A homogeneous transformation matrix for calibration and alignment of the actuator end is calculated according to the direction vector to obtain a calibration result.

2. The robot external actuator calibration method according to claim 1, characterized in that: The end of the manipulator with the calibration plate contacts the actuator in different postures to obtain two different circular marking points and a corresponding preset transformation matrix from the base of the manipulator to the end, which also includes: The calibration plate is fixedly set at the end of the robotic arm, the posture of the robotic arm end is adjusted multiple times, and multiple images are taken and the posture of the robotic arm end is recorded to obtain the posture of the robotic arm end; Determine the mapping relationship between pixel coordinates and point cloud coordinates based on the intrinsic parameter matrix of the camera and projector of the structured light system; The matrix from the camera coordinate system to the robot arm base coordinate system is calibrated according to the robot arm end posture and the intrinsic parameter matrix to obtain a preset hand-eye matrix.

3. The robot external actuator calibration method according to claim 1, characterized in that: The three-dimensional point cloud coordinates of the two circular marking points are calculated based on the mapping relationship between the pixel coordinates and the point cloud coordinates in the structured light system, including: Move the two circular marking points of the calibration plate into the field of view of the structured light system, and capture images of the marking points; Perform a circle center mark fitting operation according to the mark point image to obtain the circle center pixel coordinates; The point cloud coordinates corresponding to the circle center pixel coordinates are calculated based on the mapping relationship between the pixel coordinates and the point cloud coordinates to obtain the three-dimensional point cloud coordinates of the circular marking point.

4. The robot external actuator calibration method according to claim 1, characterized in that: The step of calculating the position of the actuator end in the robot arm base coordinate system according to the three-dimensional point cloud coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates includes: Calculating point cloud homogeneous coordinates according to the three-dimensional point cloud coordinates; The position of the actuator end in the robot arm base coordinate system is calculated according to the point cloud homogeneous coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates.

5. The robot external actuator calibration method according to claim 1, characterized in that: The step of calculating the homogeneous transformation matrix for calibrating and aligning the actuator end according to the direction vector to obtain the calibration result includes: The rotation axis vector is obtained by performing a vector cross product calculation based on the normalized direction vector and the normal vector of any point in the robot base coordinate system; Constructing a rotation matrix according to the rotation axis vector and the vector angle, wherein the vector angle is the angle between the direction vector and the normal vector of the arbitrary point; A homogeneous transformation matrix for calibration and alignment of the actuator end is calculated according to the rotation matrix and the preset translation vector to obtain a calibration result.

6. The robot external actuator calibration method according to claim 5, characterized in that: The step of calculating the homogeneous transformation matrix for calibrating and aligning the actuator end according to the rotation matrix and the preset translation vector to obtain the calibration result further includes: The actuator coordinates calculated for the first time are used as the pose homogeneous coordinates of the current circular mark point when the end of the robot arm is in the first pose state; The preset translation vector is constructed according to the pose homogeneous coordinates and the coordinates of the arbitrary point.

7. A robot external actuator calibration device, characterized in that: include: A posture marking unit is used to contact the actuator with different postures through the end of the robot arm with a calibration plate to obtain two different circular marking points and the corresponding preset transformation matrix from the base of the robot arm to the end; A coordinate calculation unit, used to calculate the three-dimensional point cloud coordinates of the two circular marking points respectively based on the mapping relationship between the pixel coordinates and the point cloud coordinates in the structured light system; A matrix transformation unit, used for calculating the transformation matrix between the two postures of the end of the robot arm according to the preset transformation matrix to obtain a posture transformation matrix; An end positioning unit is used to calculate the position of the actuator end in the robot arm base coordinate system according to the three-dimensional point cloud coordinates, the posture transformation matrix and the preset hand-eye matrix to obtain the actuator coordinates; A vector calculation unit, used for calculating the direction vector of the actuator end in the robot arm base coordinate system through two different actuator coordinates; A homogeneous calibration unit is used to calculate a homogeneous transformation matrix for calibration alignment of the actuator end according to the direction vector to obtain a calibration result.

8. The robot external actuator calibration device according to claim 7, characterized in that: The coordinate calculation unit is specifically used for: Move the two circular marking points of the calibration plate into the field of view of the structured light system, and capture images of the marking points; Perform a circle center mark fitting operation according to the mark point image to obtain the circle center pixel coordinates; The point cloud coordinates corresponding to the circle center pixel coordinates are calculated based on the mapping relationship between the pixel coordinates and the point cloud coordinates to obtain the three-dimensional point cloud coordinates of the circular marking point.

9. The robot external actuator calibration device according to claim 7, characterized in that: The homogeneous calibration unit is specifically used for: The rotation axis vector is obtained by performing a vector cross product calculation based on the normalized direction vector and the normal vector of any point in the robot base coordinate system; Constructing a rotation matrix according to the rotation axis vector and the vector angle, wherein the vector angle is the angle between the direction vector and the normal vector of the arbitrary point; A homogeneous transformation matrix for calibration and alignment of the actuator end is calculated according to the rotation matrix and the preset translation vector to obtain a calibration result.

10. A robot external actuator calibration device, characterized in that: The device comprises a processor and a memory; The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the robot external actuator calibration method according to any one of claims 1-6 according to the instructions in the program code.

Images