Automatic calibration equipment and calibration method for line laser sensor

Abstract

The invention belongs to the field of industrial robot visual control, and provides an automatic calibration device and method for a line laser sensor, the device comprises a calibration ball, a base and a bending connecting rod, one end of the bending connecting rod is movably connected to the base, and the bending connecting rod can adjust the included angle formed by the bending connecting rod and the base on the base; the other end of the bending connecting rod is sleeved with the calibration ball, and the calibration ball can rotate on the bending connecting rod. The calibration device is composed of the calibration ball, the base and the bent connecting rod, and is compact in structure and easy to operate. The design of the bending connecting rod allows the position and the angle of the calibration ball to be adjusted in multiple directions, and the flexibility and the accuracy of calibration are improved. Through introduction of the rotary joint and the angle measuring device, angle adjustment in the calibration process is more accurate, and angle data can be recorded in real time.

Description

Technical Field

[0001] The invention belongs to the field of industrial robot vision control, and in particular relates to an automatic calibration device and a calibration method for a line laser sensor. Background Art

[0002] Line laser sensors can be installed on industrial robot arms, using the collected laser data points to provide position information for the industrial robot, guiding the industrial robot arm to complete tasks such as welding, painting, and handling. Line laser sensors can emit line structured light to form a light plane that intersects with an object, and then the integrated visual sensor collects the coordinate information of the intersecting light pattern. The coordinate system corresponding to this coordinate information is the sensor coordinate system. After the line laser is installed on the industrial robot arm, its tool coordinate system needs to be determined. , the data point coordinates collected by the line laser sensor can be converted to the robot coordinate system through the following formula, thereby guiding the robot to work. The process is called calibration of the robot and laser sensor.

[0003] in, For the Laser point cloud The coordinates of the data points in the robot coordinate system; For the The robot end coordinate system corresponding to the laser point cloud; Laser point cloud The point cloud The coordinates of the data point in the sensor coordinate system.

[0004] Generally, a line laser sensor is used to scan a sphere. is correct, then all These data points will be located on a sphere and share a center. For one Matrix, there are 7 unknowns, which are the coordinates and angles of the laser sensor coordinate system in the robot's terminal coordinate system. If there is no error in the robot's posture and the laser point cloud position, the robot only needs to sample 7 sets of point clouds in 7 different postures to solve T. However, the robot's positioning accuracy and the laser sensor's measurement accuracy cannot be error-free. According to statistics, the robot's positioning error, that is, the absolute accuracy (not the repositioning accuracy) is generally around 0.2mm, and the accuracy of the laser point cloud is also around 0.1mm. In this case, solve the optimization formula of the following formula. When E is the minimum, T is the optimal solution.

[0005] in, The center of the calibration ball.

[0006] Tool coordinate system The accuracy directly affects the positioning effect of the industrial robot laser sensor and is very important. In order to improve the calibration accuracy, the sampling points should meet the following requirements: The number of sampling points needs to be much larger than 7, generally larger than 30, to form an overdetermined system of equations to find its optimal solution.

[0007] The position and angle differences of the robot end coordinate system between each sampling point should be as large as possible. Because if the difference is small, when Ti satisfies one equation, it also almost satisfies other equations. In extreme conditions, if the difference is 0, it is equivalent to repeated sampling.

[0008] The radius of the arc formed by the intersection of the plane where the laser line in each sampling point is located and the calibration sphere cannot be too small, and generally cannot be less than 0.2R, where R is the radius of the calibration circle. If R is too small, the coordinate error of the sphere center calculated by the image processing algorithm will increase. In extreme cases, when the radius is 0, the plane where the laser line is located is tangent to or separated from the calibration sphere, and the corresponding sphere center cannot be calculated, then the sampling point is an invalid point.

[0009] Based on the above three requirements, the workload of manual calibration sampling is very large, and it is necessary to manually guide the robot to collect more than 30 data points, which is very troublesome. At the same time, the calibration of the robot and the line laser sensor is a task that needs to be carried out frequently, and it needs to be performed every time the position of the line laser sensor is changed. Therefore, it is very important to develop an automated calibration method for line laser sensors and robots.

[0010] To meet the above three conditions, the robot needs to perform automated sampling. First, the rotation center of the robot end must be determined when sampling. This is because the robot has a large arm span, generally greater than 1m. If the actual rotation center position is significantly different from the optimal rotation position, the posture of the robot end coordinate system will change slightly during the sampling process, and the laser line will separate from the calibration ball, making it impossible to obtain a valid sampling point. At the same time, there are many types of optimization algorithms to choose from, such as Newton's downhill method, least squares method, etc. These optimization algorithms are all local optimization algorithms and cannot achieve global optimization. These optimization algorithms can only seek an optimal solution near the initial solution and cannot obtain the final accurate solution. Summary of the invention

[0011] The object of the present invention is to provide an automated calibration device and a calibration method for a line laser sensor, so as to solve the problem that the accurate value of the tool coordinate system cannot be obtained and the workload of manual sampling is large.

[0012] To achieve the above object, the present invention adopts the following technical solutions: In the first aspect, the present invention provides an automatic calibration device for a line laser sensor, comprising a calibration ball, a base and a bending connecting rod, wherein one end of the bending connecting rod is movably connected to the base, and the bending connecting rod can adjust the angle formed with the base on the base; the calibration ball sleeve is installed on the other end of the bending connecting rod, and the calibration ball can rotate on the bending connecting rod.

[0013] Furthermore, one end of the bending connecting rod is a straight rod, and the other end is a gate-shaped bending rod. The proximal end of the gate-shaped bending rod is fixedly connected to the straight rod, and the straight rod is connected to the base through a hinge support. The bending connecting rod can swing in the horizontal direction around the connection point; the distal end of the gate-shaped bending rod is parallel to the base, and is arranged in the calibration sphere to coincide with the diameter of the calibration sphere.

[0014] Furthermore, a rotation joint is arranged on the straight rod and the distal end of the gate-shaped bending rod. The straight rod has a vertical rotation joint, and the distal end of the gate-shaped bending rod has a horizontal rotation joint. The distal ends of the straight rod and the gate-shaped bending rod can rotate.

[0015] Furthermore, the rotating joints are all provided with angle measuring devices.

[0016] Furthermore, the bent connecting rod is a steel connecting rod.

[0017] Furthermore, a semicircular red aiming line is provided on the surface of the calibration ball, and a counterweight is provided on the semicircle corresponding to the semicircular red aiming line.

[0018] Furthermore, the center position of the counterweight is coplanar with the plane where the semicircular red aiming line is located, and the plane where the semicircular red aiming line is located is perpendicular to the horizontal plane.

[0019] In a second aspect, the present invention provides a calibration method for an automated calibration device of a line laser sensor, comprising: Adjust the two rotating joints so that the red aiming line of the calibration ball coincides with the laser plane, and determine the initial value of the tool coordinate system of the laser sensor; Determine the rotation center of the laser sensor when the robot is automatically sampling, and complete the calibration of the line laser and the robot tool coordinate system.

[0020] Furthermore, the initial value of the tool coordinate system of the laser sensor is determined, including: Estimate the range of motion of the effective measurement area of ​​the robotic arm, where the light plane of the laser sensor intersects with the calibration sphere; Loosen the hinge support, adjust the straight rod section of the calibration device to coincide with the Z axis of the robot coordinate system, and then lock it; Loosen the horizontal rotation joint, adjust the distal end of the gate-shaped bending rod of the calibration device to coincide with the X-axis of the robot coordinate system, and then lock it; Loosen the hinge support and rotate the calibration ball until the plane where the semicircular red aiming line is located is parallel to the Z axis of the robot coordinate system; at this time, the direction from the center of the circle to the origin of the semicircular red aiming line is the same as and opposite to the Z axis of the robot coordinate system. When they are the same, the direction is:

[0021] Using the calibrated TCP, touch the midpoint of the red meridian to determine the coordinates of the point.

[0022]

[0023] At this time, the center of the circle The coordinates of

[0024] Among them, is the position of the midpoint of the semicircular red aiming line, is the distance from the origin of the laser coordinate system to the midpoint of the semicircular red aiming line; Reset the readings of the angle measuring devices of all rotating axes to zero and establish a posture at the center of the sphere. The posture is expressed as:

[0025] The robot is located at the center of the sphere, and its X, Y, and Z axes are parallel to the robot's X, Y, and Z axes. Guide the robot to ensure that the line laser is projected onto the calibration sphere. The plane where the line laser is located should pass through the center of the sphere, and the (0,0) point of the line laser should be located at the vertex of the hemisphere. Loosen all rotating joints, adjust the rotation angle of the horizontal and vertical axes to make the semicircular red meridian coincide with the projection line of the laser, and record the axis readings. and ; According to the rotation process of the calibration ball, the direction of the line laser X axis in the robot coordinate system The calculation method is:

[0026]

[0027] Similarly, the direction of the Z axis of the line laser in the robot coordinate system The calculation method is:

[0028]

[0029] At this time, the direction of the Y1 axis of the line laser is determined by the right-hand rule

[0030] The posture of the line laser in the robot coordinate system is expressed as:

[0031] in, , , For vector The three components of , , For vector The three components of , and For vector The three components of At the same time, record the coordinate system of the robot flange where the laser is installed as ,have:

[0032] Initial value of the tool coordinate system of the laser sensor .

[0033] Furthermore, the rotation center of the laser sensor is determined when the robot is automatically sampling, and the calibration of the line laser and the robot tool coordinate system is completed, including: In the process of collecting point clouds, when the sensor is translated, is the tool coordinate system, Initial posture, along , , The laser sensor is translated to obtain the sampling points of the flange posture as follows:

[0034] During the point cloud collection process, the sensor The axis rotates with is the tool coordinate system, is the initial posture, and the flange posture is calculated as follows:

[0035]

[0036]

[0037] in, is the i-th sampling The angle of rotation, , , for The three components of During the rotation of the laser sensor, the laser plane intersects the spherical surface and passes through the center of the sphere. The calculation method and Around same; Will and And the corresponding point cloud data, and the initial tool coordinate system into the optimization formula: in, The center of the calibration ball The tool coordinate system of the line laser sensor in the robot system is calculated and calibrated.

[0038] Compared with the prior art, the present invention has the following technical effects: The calibration device of the present invention is composed of a calibration ball, a base and a bending connecting rod, and has a compact structure and is easy to operate. The design of the bending connecting rod allows the position and angle of the calibration ball to be adjusted in multiple directions, thereby improving the flexibility and accuracy of the calibration. The introduction of the rotating joint and the angle measuring device makes the angle adjustment in the calibration process more accurate, and the angle data can be recorded in real time.

[0039] The semicircular red aiming line set on the surface of the calibration ball provides an intuitive reference for calibration and simplifies the calibration process. The setting of the counterweight ensures the stability of the calibration ball during rotation and improves the reliability of calibration.

[0040] The present invention provides a basis for determining the initial value of the tool coordinate system of the laser sensor by adjusting the rotating joint so that the red aiming line of the calibration ball coincides with the laser plane. Detailed step-by-step instructions (such as estimating the robot's range of motion, adjusting the corresponding relationship between the calibration device and the robot coordinate system, rotating the calibration ball, etc.) ensure the accuracy and operability of the calibration. By using the calibrated TCP to touch the midpoint of the red meridian, combined with the data from the angle measurement device, the center coordinates of the calibration ball and the initial posture of the laser sensor can be accurately calculated.

[0041] In the process of collecting point clouds, the present invention can automatically collect data points by translating and rotating the laser sensor, thereby improving the sampling efficiency. A method for calculating the robot posture during sampling is given to ensure that the laser plane intersects with the calibration sphere and the distance is reasonable, providing a reliable data basis for subsequent optimization calculations.

[0042] By bringing the collected data points and the initial tool coordinate system into the optimization formula, the precise tool coordinate system of the line laser sensor in the robot system can be calculated.

[0043] The application of optimization formula makes the calibration process more scientific and accurate, and can automatically search for local optimization solutions, improving the accuracy and efficiency of calibration.

[0044] The entire calibration process of the present invention only requires workers to install the equipment and ensure that the red aiming line of the calibration ball coincides with the laser plane, and the remaining steps can be completed in an automated manner, greatly reducing labor costs.

[0045] The operation of the equipment is simple and easy to understand, does not require high technical skills from workers, and is easy to promote and apply.

[0046] This technical solution achieves accurate and automatic calibration of line laser sensors and robot tool coordinate systems through equipment design and systematic calibration methods. The equipment has a simple structure, flexible operation, low cost, and a scientific, accurate, and efficient calibration method. The promotion and application of this technology will help improve the integration and efficiency of robots and line laser sensors, and provide strong support for the development of industrial automation and intelligent manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the structure of the present invention.

[0048] Figure 2 Schematic diagram of correct and incorrect rotation center. DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with the accompanying drawings: Example 1, please refer to Figure 1 The present invention provides an automatic calibration device for a line laser sensor, comprising a calibration ball 1, a base 4 and a bending connecting rod 2, wherein one end of the bending connecting rod 2 is movably connected to the base 4, and the bending connecting rod 2 can adjust the angle between the base 4 and the base 4 on the base 4; the calibration ball 1 is sleeved and installed on the other end of the bending connecting rod 2, and the calibration ball 1 can rotate on the bending connecting rod 2.

[0050] The calibration device of the present invention is composed of a calibration ball, a base and a bending connecting rod, and has a compact structure and is easy to operate. The design of the bending connecting rod allows the position and angle of the calibration ball to be adjusted in multiple directions, thereby improving the flexibility and accuracy of the calibration. The introduction of the rotating joint and the angle measuring device makes the angle adjustment in the calibration process more accurate, and the angle data can be recorded in real time.

[0051] Embodiment 2, the present invention provides an automatic calibration device for a line laser sensor, specifically comprising: The calibration ball 1 is a standard sphere with a radius of , which is generally between 15 and 40 mm. There is a through hole in the center of the ball, which passes through the center of the ball and has a length equal to the diameter of the ball. The diameter of the through hole is slightly larger than the diameter of the bent connecting rod 2. The diameter of the through hole should ensure that the calibration ball can rotate under the action of external force and that the position of the calibration ball remains unchanged after the external force is removed.

[0052] On the surface of the calibration ball, there is a red semicircular red aiming line 11, see Figure 1 The width of the semicircular red aiming line 11 should be as small as possible, but should ensure that the human eye can quickly identify it, generally about 1 mm.

[0053] The bottom of the calibration ball 1 is a counterweight 3, the center of which is coplanar with the plane formed by the semicircular red aiming lines 11 and is located below the semicircular meridian. In this way, the calibration ball is placed on the connecting rod, and the rotation switch on the AB axis is turned on. Under the action of the counterweight, the plane formed by the semicircular red aiming lines 11 will automatically be perpendicular to the horizontal plane.

[0054] The base 4 is a steel plate or other material with strong rigidity. There are three fulcrums under the plate, which can form a triangle, preferably an isosceles triangle, which is more stable. The number of fulcrums should not exceed 3, because any 3 points can determine a plane. If the remaining points are not coplanar with these 3 points due to processing reasons, it will cause the support and the calibration ball to shake, resulting in an increase in the calibration error.

[0055] The base and the bent connecting rod are connected by a hinge support 5 with a switch function. When the hinge support is opened, the bent connecting rod can rotate around the connection point. After the shaft is locked, the position of the connecting rod remains unchanged.

[0056] The bending connecting rod is provided with two rotating joints on the axes AB and CD, and an angle measuring device is provided on the rotating axis. When the switch is on, the connecting rod can rotate around the axis; when the switch is on, the calibration ball can rotate around the horizontal axis. When the switch is off, the connecting rod and the calibration ball can rotate again. The bending connecting rod needs to have a large rigidity, so that after all switches are locked, the slight shaking of the calibration ball will not have a significant impact on the calibration error. Therefore, the bending connecting rod is preferably made of steel. At each locking, the reading of the angle measuring device should automatically return to zero.

[0057] The Y axis of the calibration device is the ray from B to C, and the Z axis is the ray from A to B.

[0058] The technical effect analysis of the automated calibration equipment for this line laser sensor is as follows: By using a standard sphere as the calibration ball, the accuracy and consistency of the calibration benchmark is ensured. The radius of the sphere is between 15 and 40 mm, which is easy to operate and ensures sufficient accuracy. The semicircular red aiming line design on the calibration ball allows the human eye to quickly identify and align, improving the efficiency of calibration.

[0059] The setting of the counterweight ensures that the calibration ball can automatically adjust to a stable state after being placed, so that the plane formed by the semicircular red aiming lines is perpendicular to the horizontal plane, further improving the accuracy of the calibration.

[0060] The base is made of a highly rigid material, and the number and layout of the fulcrums (isosceles triangle) are carefully designed to ensure the stability of the entire calibration equipment and reduce shaking and errors caused by external factors.

[0061] The design of the bent connecting rod and the hinge support connected to it allow the calibration ball to be flexibly adjusted in multiple directions to meet the needs of different calibration scenarios.

[0062] The rotating joint and angle measuring device on the connecting rod not only allow the calibration ball to rotate, but also accurately measure the rotation angle, providing more data support for the calibration process.

[0063] The switch function of the hinged support allows the connecting rod to rotate freely when needed, and maintain its position when locked, improving the convenience and accuracy of operation.

[0064] The bent connecting rod is made of steel, which ensures its high rigidity and stable performance even during long-term use, reducing calibration errors caused by connecting rod deformation.

[0065] The design of the angle measuring device automatically returning to zero each time it is locked simplifies the preparation work before calibration and improves the accuracy of calibration.

[0066] The design of the entire calibration equipment takes easy maintenance into consideration. Replacement of the calibration ball, cleaning and lubrication of the connecting rod, etc. are all relatively simple and convenient.

[0067] This automated calibration equipment effectively improves the calibration efficiency and accuracy of line laser sensors through its precise, stable, flexible and durable design.

[0068] The use of the equipment not only simplifies the calibration process, but also reduces the skill requirements for operators, making the calibration work more convenient and reliable.

[0069] In fields such as industrial automation and intelligent manufacturing, this device is expected to provide strong technical support for the widespread application of line laser sensors.

[0070] In summary, the automated calibration equipment for this line laser sensor has significant technical advantages and effects, and can meet the calibration requirements of high precision and high efficiency.

[0071] Embodiment 3, a calibration method of an automated calibration device for a line laser sensor, comprising: Adjust the two rotating joints so that the red aiming line of the calibration ball coincides with the laser plane, and determine the initial value of the tool coordinate system of the laser sensor; Determine the rotation center of the laser sensor when the robot is automatically sampling, and complete the calibration of the line laser and the robot tool coordinate system.

[0072] Specific: Step 1: Determine the initial solution of the tool coordinate system.

[0073] (1) Estimate the range of the robot's effective measurement area and ensure that the laser sensor's light plane intersects the calibration sphere after installation. Then, place the three legs on the base of the standard device in a flat and stable position.

[0074] (2) Loosen the hinge support, adjust the Z axis of the calibration device to roughly coincide with the Z axis of the robot coordinate system, and then lock it. For the robot coordinate system with a vertical Z axis, due to the influence of the calibration ball counterweight, after loosening the vertical rotation joint, under the action of gravity, the plane where the semicircular red aiming line 11 is located will automatically move to be parallel to the Z axis of the robot coordinate system.

[0075] (3) Loosen the horizontal rotation joint, adjust the X-axis of the calibration device to roughly coincide with the X-axis of the robot coordinate system, and then lock it.

[0076] Loosen the hinge support and rotate the calibration ball until the plane where the semicircle meridian is located is parallel to the Z axis of the robot coordinate system. For the robot coordinate system with a vertical Z axis, due to the influence of the calibration ball counterweight, after loosening the joint O, under the action of gravity, the plane where the semicircle red aiming line 11 is located will automatically move to be parallel to the Z axis of the robot coordinate system. At this time, the direction from the center of the circle to the origin of the semicircle red aiming line 11 is the same as and opposite to the Z axis of the robot coordinate system. When the same, the direction is:

[0077] (4) Use the calibrated TCP of other mechanical devices, such as the tip of the welding gun wire, to touch the midpoint of the semicircular red aiming line 11 and determine the coordinates of the point. .

[0078]

[0079] At this time, the center of the circle The coordinates of

[0080] Among them, is the position of the midpoint of the semicircular red aiming line 11, is the distance from the origin of the laser coordinate system to the midpoint of the semicircular red aiming line 11. and If they are the same, the value is the maximum value of the Z coordinate of the laser point cloud, otherwise it is the minimum value.

[0081] (5) Figure 1 The readings of all the rotation axes in the sphere are reset to zero. A posture is established at the center of the sphere, and its posture can be expressed as:

[0082] From the adjustment process from 2 to 4 steps, we can see that: The robot is located at the center of the sphere, and its X, Y, and Z axes are parallel to the robot's X, Y, and Z axes.

[0083] (6) Guide the robot to ensure that the line laser is projected onto the calibration sphere. The plane where the line laser is located should roughly pass through the center of the sphere, and the (0,0) point of the line laser should be roughly located at the vertex of the hemisphere.

[0084] (7) Loosen joints N and M, and adjust the rotation angles of the horizontal and vertical axes so that the semicircular red aiming line 11 roughly coincides with the projection line of the laser. The positions of the horizontal and vertical axes are shown in Figure 1 . And record the axis reading and Since the center of the ball is located on the axis of the two rotation axes, the position of the center of the ball remains unchanged during the rotation process. According to the rotation process of the calibration ball, the direction of the line laser X axis in the robot coordinate system The calculation method is:

[0085]

[0086] Similarly, the direction of the Z axis of the line laser in the robot coordinate system The calculation method is:

[0087]

[0088] At this time, the direction of the Y1 axis of the line laser is determined by the right-hand rule.

[0089]

[0090] At this time, the posture of the line laser in the robot coordinate system can be expressed as:

[0091] in, , , For vector The three components of , , For vector The three components of , and For vector The three components.

[0092] At the same time, record the coordinate system of the robot flange where the laser is installed as ,have:

[0093] therefore:

[0094] At this point, the initial value of the tool coordinate system of the laser sensor is obtained According to the results of multiple actual tests, the position error of the initial value is less than 5 mm, and the angle error is less than 5 degrees. Although this accuracy cannot be used in actual work, such as welding, handling and testing, it can be used as the initial value for solving the optimization problem (2) and then finding the global optimal solution.

[0095] The second step is to determine the rotation center of the laser sensor.

[0096] During the point cloud acquisition process, the laser sensor will undergo two types of motion, one is translation and the other is rotation. When rotating, the rotation center of the laser sensor needs to be correctly defined. Otherwise, during the acquisition process, when the sensor rotates, the laser point cloud will deviate too far from the positioning sphere, resulting in the laser plane being unable to intersect with the calibration sphere and the point cloud on the sphere being unable to be acquired.

[0097] If the rotation center of the sensor is defined at the center of the calibration sphere during point cloud acquisition, then no matter how large the rotation angle is, the laser will always shine on the calibration sphere and the rotation plane will pass through the center of the sphere.

[0098] If during the process of collecting point clouds, the sensor is moved horizontally, is the tool coordinate system, Initial posture, along , , The laser sensor can be translated to obtain the sampling points of the flange posture as For example, the method is as follows:

[0099] If the sensor The axis rotates with is the tool coordinate system, is the initial posture, and its flange posture is calculated as follows:

[0100]

[0101]

[0102] in, is the i-th sampling Angle of rotation. , , for The three components.

[0103] The calculation method is the same when rotating around the other two axes.

[0104] From this calculation method, we can know that although this method changes the direction of the posture, it does not change the position of the posture. No matter how big the laser sensor is, the Z axis of the sensor coordinate system still passes through the center of the calibration sphere. This ensures that during the rotation of the laser sensor, the laser plane always intersects the sphere and passes through the center of the sphere. The calculation method for the other two axes is the same as Around same.

[0105] Will and And the corresponding point cloud data, and the initial tool coordinate system into the optimization formula: , The center of the calibration ball The tool coordinate system of the line laser sensor in the robot system can be accurately calculated to achieve high-precision calibration of the two.

[0106] The present invention provides a device and method for efficiently and accurately completing the calibration of a robot and a laser. The method can instruct the robot to automatically collect the data required for calibration and calculate the tool coordinates in Formula 1.

[0107] When in use, workers only need to project the laser line onto the surface of the calibration ball, and then rotate the calibration ball so that the red line on the calibration ball is roughly aligned with the laser line. This method can automatically determine the rotation center of the robot end during calibration and determine a more accurate initial value of the tool coordinates.

[0108] Using this rotation center, the robot can significantly change the rotation posture of the end coordinate system and ensure that the light plane intersects with the calibration sphere, efficiently collecting multiple data points; using the initial value of the tool coordinates, various optimization algorithms can be used to determine the precise value of the tool coordinate system to avoid the optimization algorithm giving an unreasonable local optimization solution.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An automatic calibration device for a line laser sensor, characterized in that: The device comprises a calibration ball (1), a base (4) and a bending connecting rod (2), wherein one end of the bending connecting rod (2) is movably connected to the base (4), and the bending connecting rod (2) can adjust the angle formed with the base (4) on the base (4); the calibration ball (1) is sleeved and mounted on the other end of the bending connecting rod (2), and the calibration ball (1) can rotate on the bending connecting rod (2).

2. The automatic calibration device for a line laser sensor according to claim 1, characterized in that: One end of the bending connecting rod (2) is a straight rod, and the other end is a gate-shaped bending rod. The proximal end of the gate-shaped bending rod is fixedly connected to the straight rod, and the straight rod is connected to the base (4) via a hinge support (5). The bending connecting rod (2) can swing in the horizontal direction around the connection point; the distal end of the gate-shaped bending rod is parallel to the base (4) and is arranged in the calibration ball (1) to coincide with the diameter of the calibration ball (1).

3. The automatic calibration device for a line laser sensor according to claim 2, characterized in that: Rotation joints are arranged on the straight rod and the distal ends of the gate-shaped bending rod. The straight rod has a vertical rotation joint, and the distal end of the gate-shaped bending rod has a horizontal rotation joint. The distal ends of the straight rod and the gate-shaped bending rod can rotate.

4. The automatic calibration device for a line laser sensor according to claim 3, characterized in that: Angle measuring devices are provided on the rotating joints.

5. The automatic calibration device for a line laser sensor according to claim 1, characterized in that: The bent connecting rod (2) is a steel connecting rod.

6. The automatic calibration device for a line laser sensor according to claim 1, characterized in that: A semicircular red aiming line (11) is provided on the surface of the calibration ball (1), and a counterweight (3) is provided on the semicircle corresponding to the semicircular red aiming line (11).

7. The automatic calibration device for a line laser sensor according to claim 6, characterized in that: The center position of the counterweight (3) is coplanar with the plane where the semicircular red aiming line (11) is located, and the plane where the semicircular red aiming line (11) is located is perpendicular to the horizontal plane.

8. A calibration method for an automated calibration device for a line laser sensor according to any one of claims 1 to 7, characterized in that: include: Adjust the two rotating joints so that the red aiming line of the calibration ball coincides with the laser plane, and determine the initial value of the tool coordinate system of the laser sensor; Determine the rotation center of the laser sensor when the robot is automatically sampling, and complete the calibration of the line laser and the robot tool coordinate system.

9. The calibration method of the automatic calibration equipment of a line laser sensor according to claim 8, characterized in that: Determine the initial value of the tool coordinate system of the laser sensor, including: Estimate the range of motion of the effective measurement area of ​​the robotic arm, where the light plane of the laser sensor intersects with the calibration sphere; Loosen the hinge support, adjust the straight rod section of the calibration device to coincide with the Z axis of the robot coordinate system, and then lock it; Loosen the horizontal rotation joint, adjust the distal end of the gate-shaped bending rod of the calibration device to coincide with the X-axis of the robot coordinate system, and then lock it; Loosen the hinge support and rotate the calibration ball until the plane where the semicircular red aiming line is located is parallel to the Z axis of the robot coordinate system; at this time, the direction from the center of the circle to the origin of the semicircular red aiming line is the same as and opposite to the Z axis of the robot coordinate system. When they are the same, the direction is: Use the calibrated target center point TCP to touch the midpoint of the red meridian to determine the coordinates of the point. At this time, the center of the ball The coordinates of in, is the position of the midpoint of the semicircular red aiming line, is the distance between the origin of the laser coordinate system and the midpoint of the semicircular red aiming line, It is the direction vector from the origin of the laser coordinate system to the midpoint of the semicircular red aiming line; Reset the readings of the angle measuring devices of all rotating axes to zero and establish a posture at the center of the sphere. The posture is expressed as: The X, Y, and Z axes of the robot are parallel to the X, Y, and Z axes of the robot. Guide the robot to ensure that the line laser is projected onto the calibration sphere. The plane where the line laser is located should pass through the center of the sphere, and the (0,0) point of the line laser should be located at the vertex of the hemisphere. Loosen all rotating joints, adjust the rotation angle of the horizontal and vertical axes to make the semicircular red meridian coincide with the projection line of the laser, and record the axis readings. and ; According to the rotation process of the calibration ball, the direction of the line laser X axis in the robot coordinate system The calculation method is: Similarly, the direction of the Z axis of the line laser in the robot coordinate system The calculation method is: At this time, the direction of the Y1 axis of the line laser is determined by the right-hand rule The posture of the line laser in the robot coordinate system is expressed as: in, , , For vector The three components of , , For vector The three components of , and For vector The three components of At the same time, record the coordinate system of the robot flange where the laser is installed as ,have: Initial value of the tool coordinate system of the laser sensor .

10. The calibration method of the automatic calibration equipment of the line laser sensor according to claim 9, characterized in that: Determine the rotation center of the laser sensor when the robot is automatically sampling, and complete the calibration of the line laser and robot tool coordinate system, including: In the process of collecting point clouds, when the sensor is translated, is the tool coordinate system, Initial posture, along , , The laser sensor is translated to obtain the sampling points of the flange posture as follows: During the point cloud collection process, the sensor The axis rotates with is the tool coordinate system, is the initial posture, and the flange posture is calculated as follows: in, is the i-th sampling The angle of rotation, , , for The three components of During the rotation of the laser sensor, the laser plane intersects the spherical surface and passes through the center of the sphere. The calculation method and Around same; Will and And the corresponding point cloud data, and the initial tool coordinate system into the optimization formula: in, The center of the calibration ball The tool coordinate system of the line laser sensor in the robot system is calculated and calibrated.

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