External parameter calibration method and device, intelligent robot and computer-readable storage medium

Abstract

The present application discloses an external parameter calibration method for calibrating external parameters for a radar. The external parameter calibration method includes: generating multiple groups of test external parameters at predetermined step intervals within a predetermined external parameter range; calculating the reference height of the reference surface detected by the radar based on the multiple groups of test external parameters, and generating multiple groups of test heights; obtaining the test external parameter corresponding to the test height with the smallest difference from the reference height in the multiple groups of test heights as the external parameter to be selected; judging whether the height difference between the test height corresponding to the external parameter to be selected and the reference height is within a preset range; and if so, determining that the external parameter to be selected is the external parameter after radar calibration. The present application also discloses an external parameter calibration device, an intelligent robot, and a computer-readable storage medium. The external parameter calibration method of the present application is simple to operate, can greatly save manpower and time costs in the radar calibration process, and can obtain a higher calibration accuracy.

Description

[0001] This application is a divisional application of patent application No. 202010161044.8 (the filing date of the original application is March 10, 2020, and the invention name is external parameter calibration method and device, intelligent robot and computer-readable storage medium. Technical Field

[0002] The present application relates to the technical field of sensor external parameter calibration, and more specifically, to an external parameter calibration method and device, an intelligent robot, and a computer-readable storage medium. Background Art

[0003] LiDAR sensors are widely used in mobile robots for mapping, positioning, navigation, and obstacle avoidance. Obstacle avoidance requires the ability to identify obstacles. For accurate identification of obstacles on the ground, LiDAR sensors are the primary choice. The LiDAR's external parameters are crucial for accurate obstacle identification, directly impacting the robot's overall performance. However, installation errors are unavoidable for actual robots, and prolonged operation can also affect the LiDAR's external parameters. Therefore, automatic calibration of LiDAR's external parameters is crucial. Manual calibration is inefficient and inaccurate. Summary of the Invention

[0004] In view of this, the present invention aims to solve at least one of the problems in the related art to a certain extent. To this end, the embodiments of the present application provide an extrinsic parameter calibration method and apparatus, an intelligent robot, and a computer-readable storage medium.

[0005] The external parameter calibration method of the embodiment of the present application is used to calibrate the external parameters of the radar, and the external parameter calibration method includes: generating multiple groups of test external parameters at predetermined step intervals within a predetermined external parameter range; calculating the reference height of the reference surface detected by the radar based on the multiple groups of test external parameters, and generating multiple groups of test heights; obtaining the test external parameter corresponding to the test height with the smallest difference from the reference height in the multiple groups of test heights as the selected external parameter; judging whether the height difference between the test height corresponding to the selected external parameter and the reference height is within a preset range; and if so, determining that the selected external parameter is the external parameter after the radar calibration.

[0006] The external parameter calibration method of the implementation mode of the present application first generates multiple groups of test external parameters at a predetermined step interval within a predetermined external parameter range, and then calculates the reference height of the reference plane detected by the radar based on the multiple groups of test external parameters, and generates multiple groups of test heights at the same time, and obtains the test external parameter corresponding to the test height with the smallest difference with the reference height in the multiple groups of test heights as the selected external parameter, and finally determines whether the height difference between the test height corresponding to the selected external parameter and the reference height is within a preset range. If so, it is determined that the selected external parameter is the external parameter after radar calibration. Therefore, the external parameter calibration method of the present application selects appropriate external parameters from multiple test external parameters through calculation, is suitable for radars installed at any angle, is simple to operate, and can greatly save manpower and time costs in the radar calibration process, and can also obtain higher calibration accuracy.

[0007] In some embodiments, the reference height of the reference plane detected by the radar is calculated based on multiple sets of the test external parameters, and multiple sets of test heights are generated, including: obtaining a point cloud on the reference plane; filtering the point cloud blocked by the mounting carrier of the radar in the point cloud to form a first point cloud; and calculating the height of the first point cloud based on multiple sets of the test external parameters to generate multiple sets of test heights.

[0008] In this embodiment, the point cloud on the reference surface is first obtained, and then the point cloud blocked by the radar mounting carrier is filtered to form a first point cloud. Finally, the height of the first point cloud is calculated based on multiple sets of test external parameters to generate multiple sets of test heights. Thus, valid point clouds are used when calculating the test heights, avoiding errors caused by calculating the test height of the point cloud blocked by the mounting carrier, and making the obtained test height value more accurate.

[0009] In some embodiments, the radar is capable of rotating around a rotation axis relative to a mounting carrier of the radar, and the external parameter calibration method further includes: setting an angle interval based on the angle range of rotation of the radar around the rotation axis to form a plurality of calibration areas; and performing external parameter calibration for the radar at least once in each of the calibration areas.

[0010] In this embodiment, the radar can rotate around the rotation axis relative to the mounting carrier of the radar. Therefore, the installation position of the radar on the mounting carrier is not fixed. First, an angle interval is set according to the angle range of the radar's rotation around the rotation axis to form a plurality of calibration areas. At the same time, the radar is calibrated with external parameters at least once in each calibration area. Therefore, the radar can obtain a set of calibrated external parameters in each calibration area, so that when the radar rotates around the rotation axis, the external parameters of the radar are always calibrated external parameters, so that the radar can accurately identify obstacles when it is rotated to any angle.

[0011] In some embodiments, the radar is installed on an intelligent robot, and the reference plane is the driving surface of the intelligent robot. Before calculating the reference height of the reference plane detected by the radar based on multiple sets of test external parameters and generating multiple sets of test heights, the external parameter calibration method also includes: controlling the intelligent robot to move to a position within a preset range where there are no obstacles and the driving surface is flat.

[0012] In this embodiment, the radar is installed on the intelligent robot, and the reference surface is the driving surface of the intelligent robot. The intelligent robot is controlled to move to a position within a preset range where there are no obstacles and the driving surface is flat. In this way, the influence of the point cloud on the obstacle on the calculated test height can be avoided, and the inaccurate calculated test height caused by the unevenness of the driving surface can be avoided, which further leads to inaccurate external parameters. Therefore, the radar can obtain accurate external parameters.

[0013] In some embodiments, the external parameters include the installation height, pitch angle, and roll angle of the radar.

[0014] In this embodiment, the external parameters include the installation height, pitch angle and roll angle of the radar. Therefore, the best installation height, pitch angle and roll angle of the radar can be obtained through the external parameter calibration method, so that the radar can better identify obstacles.

[0015] In some embodiments, the test extrinsic parameter corresponding to the test height having the smallest difference with the reference height among the multiple groups of test heights obtained is the external parameter to be selected, including: when the test height having the smallest difference with the reference height corresponds to multiple groups of test extrinsic parameters, the test extrinsic parameter of the test height obtained for the first time is taken as the external parameter to be selected.

[0016] In this embodiment, when there are multiple sets of test external parameters corresponding to the test height with the smallest difference from the reference height, the test external parameter that obtains the minimum test height for the first time is taken as the external parameter to be selected. In this way, the problem of having multiple sets of test external parameters and being unable to determine the external parameter to be selected can be avoided. At the same time, taking the test external parameter for the first time is conducive to reducing errors and making the obtained external parameter to be selected more accurate.

[0017] In some embodiments, the extrinsic parameter calibration method further includes: when it is determined that the height difference between the test height corresponding to the selected extrinsic parameter and the reference height is not within a preset range, resetting the extrinsic parameter range and / or the step interval.

[0018] In this embodiment, when the height difference between the test height corresponding to the selected external parameter and the reference height is not within the preset range, the external parameter range and / or step interval are reset, thereby enabling the radar to obtain appropriate external parameters with a greater probability when recalibrating the external parameters, thereby avoiding the situation where appropriate external parameters cannot be obtained due to repeated calculation of previous data.

[0019] The external parameter calibration device of the embodiment of the present application is used to calibrate the radar and is applied to an intelligent robot. The external parameter calibration device includes a generation module, a calculation module, an acquisition module, a judgment module and a determination module. The generation module is used to generate multiple groups of test external parameters at a predetermined step interval within a predetermined external parameter range; the calculation module is used to calculate the reference height of the reference plane detected by the radar based on the multiple groups of test external parameters, and generate multiple groups of test heights; the setting module is used to obtain the test external parameter corresponding to the test height with the smallest difference from the reference height in the multiple groups of test heights as the selected external parameter; the judgment module is used to judge whether the height difference between the test height corresponding to the selected external parameter and the reference height is within a preset range; the determination module is used to determine that the selected external parameter is the external parameter after the radar calibration when the result of the judgment module is yes.

[0020] In the external parameter calibration device of the embodiment of the present application, first, multiple groups of test external parameters are generated within a predetermined external parameter range at a predetermined step interval, and then the reference height of the reference plane detected by the radar is calculated respectively based on the multiple groups of test external parameters, and multiple groups of test heights are generated at the same time. The test external parameter corresponding to the test height with the smallest difference with the reference height in the multiple groups of test heights is obtained as the selected external parameter, and finally it is judged whether the height difference between the test height corresponding to the selected external parameter and the reference height is within a preset range. If so, it is determined that the selected external parameter is the external parameter after radar calibration. Therefore, the external parameter calibration method of the present application selects appropriate external parameters from multiple test external parameters through calculation, is suitable for radars installed at any angle, is simple to operate, and can greatly save manpower and time costs in the radar calibration process, and can also obtain higher calibration accuracy.

[0021] In some embodiments, the calculation module is also used to: obtain a point cloud on the reference plane; filter the point cloud blocked by the mounting carrier of the radar to form a first point cloud; and calculate the height of the first point cloud based on multiple sets of the test external parameters to generate multiple sets of the test heights.

[0022] In this embodiment, the point cloud on the reference surface is first obtained, and then the point cloud blocked by the radar mounting carrier is filtered to form a first point cloud. Finally, the height of the first point cloud is calculated based on multiple sets of test external parameters to generate multiple sets of test heights. Thus, valid point clouds are used when calculating the test heights, avoiding errors caused by calculating the test height of the point cloud blocked by the mounting carrier, and making the obtained test height value more accurate.

[0023] In some embodiments, the radar is capable of rotating around a rotation axis relative to a mounting carrier of the radar, and the external parameter calibration device is further used to: set angle intervals based on the angle range of rotation of the radar around the rotation axis to form multiple calibration areas; and perform external parameter calibration for the radar at least once in each of the calibration areas.

[0024] In this embodiment, the radar can rotate around the rotation axis relative to the mounting carrier of the radar. Therefore, the installation position of the radar on the mounting carrier is not fixed. First, an angle interval is set according to the angle range of the radar's rotation around the rotation axis to form a plurality of calibration areas. At the same time, the radar is calibrated with external parameters at least once in each calibration area. Therefore, the radar can obtain a set of calibrated external parameters in each calibration area, so that the radar's external parameters are always calibrated external parameters during the process of the radar rotating around the rotation axis, which is conducive to the radar's accurate identification of obstacles.

[0025] In some embodiments, the radar is installed on an intelligent robot, and the reference plane is the driving surface of the intelligent robot. Before calculating the reference height of the reference plane detected by the radar based on multiple sets of test external parameters and generating multiple sets of test heights, the external parameter calibration device is also used to: control the intelligent robot to move to a position within a preset range where there are no obstacles and the driving surface is flat.

[0026] In this embodiment, the radar is installed on the intelligent robot, and the reference surface is the driving surface of the intelligent robot. The intelligent robot is controlled to move to a position within a preset range where there are no obstacles and the driving surface is flat. In this way, the influence of the point cloud on the obstacle on the calculated test height can be avoided, and the inaccurate calculated test height caused by the unevenness of the driving surface can be avoided, which further leads to inaccurate external parameters. Therefore, the radar can obtain accurate external parameters.

[0027] In some embodiments, the external parameter calibration device is used to calibrate the installation height, pitch angle and roll angle of the radar.

[0028] In this embodiment, the external parameters include the installation height, pitch angle and roll angle of the radar. Therefore, the best installation height, pitch angle and roll angle of the radar can be obtained through the external parameter calibration device, so that the radar can better identify obstacles.

[0029] In some embodiments, the acquisition module is further configured to: when a test height having the smallest difference from the reference height corresponds to multiple sets of test extrinsic parameters, take the test extrinsic parameter obtained for the first time as the to-be-selected extrinsic parameter.

[0030] In this embodiment, when there are multiple sets of test external parameters corresponding to the test height with the smallest difference from the reference height, the test external parameter that obtains the minimum test height for the first time is taken as the external parameter to be selected. In this way, the problem of having multiple sets of test external parameters and being unable to determine the external parameter to be selected can be avoided. At the same time, taking the test external parameter for the first time is conducive to reducing errors and making the obtained external parameter to be selected more accurate.

[0031] In some embodiments, the determination module is further configured to: when it is determined that the height difference between the test height corresponding to the selected external parameter and the reference height is not within a preset range, reset the external parameter range and / or the step interval.

[0032] In this embodiment, when the height difference between the test height corresponding to the selected external parameter and the reference height is not within the preset range, the external parameter range and / or step interval are reset, thereby enabling the radar to obtain appropriate external parameters with a greater probability when recalibrating the external parameters, thereby avoiding the situation where appropriate external parameters cannot be obtained due to repeated calculation of previous data.

[0033] The intelligent robot of an embodiment of the present application includes one or more processors, a memory; and one or more programs, wherein the one or more programs are stored in the memory and executed by the one or more processors, and the program includes instructions for executing the external parameter calibration method described in any of the above embodiments.

[0034] In the intelligent robot of the embodiment of the present application, first, multiple groups of test external parameters are generated within a predetermined external parameter range at a predetermined step interval, and then the reference height of the reference plane detected by the radar is calculated respectively based on the multiple groups of test external parameters, and multiple groups of test heights are generated at the same time. The test external parameter corresponding to the test height with the smallest difference with the reference height in the multiple groups of test heights is obtained as the selected external parameter, and finally it is judged whether the height difference between the test height corresponding to the selected external parameter and the reference height is within a preset range. If so, it is determined that the selected external parameter is the external parameter after radar calibration. Therefore, the external parameter calibration method of the present application selects appropriate external parameters from multiple test external parameters through calculation, is suitable for radars installed at any angle, is simple to operate, and can greatly save manpower and time costs in the radar calibration process, and can also obtain higher calibration accuracy.

[0035] The computer-readable storage medium of the embodiment of the present application, when the computer-executable instructions are executed by one or more processors, enables the processor to execute the external parameter calibration method described in any embodiment.

[0036] In the computer-readable storage medium of the embodiment of the present application, multiple groups of test external parameters are first generated within a predetermined external parameter range at a predetermined step interval, and then the reference height of the reference plane detected by the radar is calculated respectively based on the multiple groups of test external parameters, and multiple groups of test heights are generated at the same time. The test external parameter corresponding to the test height with the smallest difference with the reference height in the multiple groups of test heights is obtained as the selected external parameter, and finally it is determined whether the height difference between the test height corresponding to the selected external parameter and the reference height is within a preset range. If so, it is determined that the selected external parameter is the external parameter after radar calibration. Therefore, the external parameter calibration method of the present application selects appropriate external parameters from multiple test external parameters through calculation, is suitable for radars installed at any angle, is simple to operate, and can greatly save manpower and time costs in the radar calibration process, and can also obtain higher calibration accuracy.

[0037] Additional aspects and advantages of the embodiments of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0039] Figure 1 is a flow chart of an external parameter calibration method for some embodiments of the present application;

[0040] Figure 2 is a schematic diagram of a module of an intelligent robot according to some embodiments of the present application;

[0041] Figure 3 This is a schematic diagram of a module of an external parameter calibration device in some embodiments of the present application;

[0042] Figure 4 is a flow chart of an external parameter calibration method for some embodiments of the present application;

[0043] Figure 5 is a schematic structural diagram of an intelligent robot according to some embodiments of the present application;

[0044] Figure 6 is a schematic structural diagram of an intelligent robot according to some embodiments of the present application;

[0045] Figure 7 Schematic diagram of a scenario of an external parameter calibration method in some embodiments of the present application;

[0046] Figure 8 Schematic diagram of a scenario of an external parameter calibration method in some embodiments of the present application;

[0047] Figure 9It is a flowchart of the external parameter calibration method of some embodiments of the present application;

[0048] Figure 10 Schematic diagram of a scenario of an external parameter calibration method in some embodiments of the present application;

[0049] Figure 11 Schematic diagram of a scenario of an external parameter calibration method in some embodiments of the present application;

[0050] Figure 12 is a flow chart of an external parameter calibration method for some embodiments of the present application;

[0051] Figure 13 is a flow chart of an external parameter calibration method for some embodiments of the present application;

[0052] Figure 14 It is a flowchart of the external parameter calibration method of some embodiments of the present application;

[0053] Figure 15 It is a flowchart of the external parameter calibration method of some embodiments of the present application;

[0054] Figure 16 This is a connection diagram of a computer-readable storage medium and a processor in some embodiments of the present application. DETAILED DESCRIPTION

[0055] The following further describes the embodiments of the present application in conjunction with the accompanying drawings. The same or similar reference numerals in the accompanying drawings represent the same or similar elements or elements with the same or similar functions.

[0056] In addition, the embodiments of the present application described below in conjunction with the accompanying drawings are exemplary and are only used to explain the embodiments of the present application and should not be understood as limiting the present application.

[0057] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0058] See also Figure 1 and Figure 2 The external parameter calibration method of the embodiment of the present application is used to perform external parameter calibration for the radar 40, and the external parameter calibration method includes the following steps:

[0059] S010: generating multiple groups of test external parameters at predetermined step intervals within a predetermined external parameter range;

[0060] S020: Calculating reference heights of reference surfaces detected by the radar 40 based on multiple sets of test external parameters, and generating multiple sets of test heights;

[0061] S030: obtaining, from among the multiple groups of test heights, a test extrinsic parameter corresponding to a test height having the smallest difference from a reference height as a candidate extrinsic parameter;

[0062] S040: Determine whether the height difference between the test height and the reference height corresponding to the selected external parameter is within a preset range; and

[0063] S050: If yes, determine that the external parameter to be selected is the external parameter after calibration of the radar 40.

[0064] The intelligent robot 100 of the embodiment of the present application includes one or more processors 10, a memory 20 and one or more programs, wherein the one or more programs are stored in the memory 20 and executed by the one or more processors 10, and the program includes instructions for executing the external parameter calibration method of the embodiment of the present application. When the processor 10 executes the program, the program 10 can be used to implement steps S010, S020, S030, S040 and S050, that is, the processor 10 can be used to: generate multiple groups of test external parameters at predetermined step intervals within a predetermined external parameter range; calculate the reference height of the reference surface detected by the radar 40 based on the multiple groups of test external parameters, and generate multiple groups of test heights; obtain the test external parameter corresponding to the test height with the smallest difference from the reference height in the multiple groups of test heights as the selected external parameter; determine whether the height difference between the test height corresponding to the selected external parameter and the reference height is within a preset range; and if so, determine that the selected external parameter is the external parameter after calibration of the radar 40.

[0065] See also Figure 3The external parameter calibration device 200 of the embodiment of the present application includes a generation module 210, a calculation module 220, an acquisition module 230, a judgment module 240 and a determination module 250. The generation module 210, the calculation module 220, the acquisition module 230, the judgment module 240 and the determination module 250 can be used to implement step S010, step S020, step S030, step S040 and step S050 respectively. That is, the generation module 210 is used to generate multiple groups of test external parameters at a predetermined step interval within a predetermined external parameter range; the calculation module 220 is used to calculate the reference height of the reference plane detected by the radar 40 based on the multiple groups of test external parameters, and generate multiple groups of test heights; the acquisition module 230 is used to obtain the test external parameter corresponding to the test height with the smallest difference from the reference height in the multiple groups of test heights as the external parameter to be selected; the judgment module 240 is used to judge whether the height difference between the test height corresponding to the external parameter to be selected and the reference height is within a preset range; and the determination module 250 is used to determine that the external parameter to be selected is the external parameter after calibration of the radar 40 when the result of the judgment module 240 is yes.

[0066] In the external parameter calibration method, external parameter calibration device 200 and intelligent robot 100 of the embodiment of the present application, first, multiple groups of test external parameters are generated within a predetermined external parameter range at a predetermined step interval, and then the reference height of the reference plane detected by the radar 40 is calculated respectively based on the multiple groups of test external parameters, and multiple groups of test heights are generated at the same time. The test external parameter corresponding to the test height with the smallest difference with the reference height in the multiple groups of test heights is obtained as the selected external parameter, and finally it is judged whether the height difference between the test height corresponding to the selected external parameter and the reference height is within a preset range. If so, it is determined that the selected external parameter is the external parameter after calibration of the radar 40. Therefore, the external parameter calibration method of the present application selects appropriate external parameters from multiple test external parameters by calculation, and is suitable for radars 40 installed at any angle. It is simple to operate and can greatly save manpower and time costs in the calibration process of the radar 40, and at the same time can obtain a higher calibration accuracy.

[0067] The intelligent robot 100 may be an industrial robot, an agricultural robot, a household robot, a service robot, a cleaning robot, or the like, without limitation. Furthermore, the cleaning robot may be a sweeper, a scrubber, a vacuum cleaner, or the like. The intelligent robot 100 may also include components such as a communication interface 30 and a cleaning execution device. The intelligent robot 100 may be used to clean surfaces such as floors, tiles, pavement, or cement. The radar 40 may be a laser radar, a microwave radar, a millimeter-wave radar, or the like, without limitation.

[0068] Furthermore, the embodiment of the present application is described by taking the installation carrier of the radar 40 as the intelligent robot 100 as an example. It is understood that the installation carrier of the radar 40 can be other and is not limited here. At the same time, the radar 40 is functionally described as a laser radar. The radar 40 can be other types of radars and is not limited here.

[0069] Specifically, the radar 40 is installed on the intelligent robot 100 and can be used for mapping, positioning, navigation and obstacle avoidance of the intelligent robot 100. In step S010, multiple groups of test external parameters are generated at predetermined step intervals within a predetermined external parameter range. The predetermined external parameter range can be an external parameter range set by the user. The external parameter range is the value range of the external parameter when performing external parameter calibration. Different external parameters can be set with different external parameter ranges. The external parameter range can be a combination of multiple external parameters. For example, the external parameter range can include a combination of an installation height range, a pitch angle variation range, a roll angle variation range, a heading angle external parameter range, etc., which is not limited here.

[0070] In step S020, the reference height of the reference surface detected by the radar 40 is calculated based on multiple sets of test external parameters, and multiple sets of test heights are generated. Since the reference surface itself has a reference height, the reference height of the reference surface is calculated using external parameters to obtain the test height, thereby enabling a better comparison of the difference between the test height and the reference height. At the same time, multiple sets of test external parameters are generated in step S010. The reference height of the reference surface detected by the radar 40 is calculated based on each set of test external parameters, and a test height can be obtained. Therefore, by determining the accuracy of the test height, it can be used to reversely infer the accuracy of the test external parameter. At the same time, the same reference surface is conducive to the subsequent selection of the selected external parameter. The reference surface can be a plane of any height, for example, the reference surface is the ground, the floor, or a calibration plate parallel to the ground.

[0071] In step S030, the test extrinsic parameter corresponding to the test height with the smallest difference from the reference height in multiple groups of test heights is obtained as the extrinsic parameter to be selected. In step S020, multiple groups of test heights are obtained. Since the reference plane objectively has a reference height, the height difference between the test height obtained according to the test extrinsic parameter and the reference height is the smallest, that is, the closer the test height is to the reference height, the more accurate the extrinsic parameter corresponding to the test height with the smallest difference from the reference height is, and the error is smaller. Thus, the test extrinsic parameter corresponding to the test height with the smallest difference from the reference height in multiple groups of test heights is obtained as the extrinsic parameter to be selected, and the selection of the extrinsic parameter to be selected is closer to the most accurate extrinsic parameter. Wherein, the difference can refer to the absolute value of the difference between the test height and the reference height, and the difference can be set by the user, and can be 0.05 meters, 0.03 meters, 0.01 meters, 0.04 meters, 0.08 meters, etc., without limitation.

[0072] In step S040, it is determined whether the height difference between the test height corresponding to the to-be-selected external parameter and the reference height is within a preset range, where the preset range may be a range set by the user, indicating an error that the user can accept. Since the height difference between the test height corresponding to the to-be-selected external parameter and the reference height is the smallest, it is only necessary to determine whether the minimum height difference exceeds the preset range to determine whether the to-be-selected external parameter is a suitable external parameter.

[0073] Furthermore, if the result in step S040 is yes, step S050 is executed to determine that the candidate extrinsic parameter is a calibrated extrinsic parameter of the radar 40. That is, the height difference between the test altitude corresponding to the candidate extrinsic parameter and the reference altitude is within a preset range, indicating that when the extrinsic parameter of the radar 40 is the candidate extrinsic parameter, the data acquired by the radar 40 is relatively accurate and has a small error. Therefore, the extrinsic parameter calibration method according to the embodiment of the present application can calibrate the extrinsic parameter of the radar 40, enabling the radar 40 to accurately acquire data.

[0074] Among them, see Figure 4 In some embodiments, step S010 includes:

[0075] Step S011: setting the initial value, range and step interval of the external parameter;

[0076] Step S012: continuously accumulating a step interval from the initial value, generating a set of test external parameters for each accumulated step interval; and

[0077] Step S013: until the test external parameters cover the external parameter range, the cumulative step interval ends and multiple groups of test external parameters are generated.

[0078] First, set the initial value, range, and step interval of the extrinsic parameter. Starting from the initial value, continue accumulating a step interval. Each step interval generates a set of test extrinsic parameters until the test extrinsic parameters can cover the extrinsic parameter range. This can generate more test extrinsic parameters, which is conducive to obtaining the most appropriate calibration extrinsic parameters. Among them, the step interval, initial value, and extrinsic parameter range can all be set by the user.

[0079] See also Figure 5 and Figure 6The radar 40 includes multiple external parameters, including, in some embodiments, installation height z, pitch angle, and roll angle roll. The installation height z is the distance between the radar 40 and the bottom of the intelligent robot 100, the pitch angle pitch is the angle between the radar 40 and the horizontal plane, and the roll angle roll is the angle between the radar 40 and the vertical plane. The external parameter calibration method of this embodiment can calibrate the installation height z, pitch angle, and roll angle roll of the radar 40, enabling the radar 40 to obtain appropriate installation height z, pitch angle, and roll angle roll, thereby making the radar 40 more accurate in obstacle recognition. Of course, in addition to the external parameters such as installation height z, pitch angle, and roll angle roll, other external parameters can also be calibrated.

[0080] Please combine Figure 4 In one embodiment, the radar 40 is a laser radar, and the external parameters of the laser radar that need to be calibrated are the installation height z, pitch angle, and roll angle. The initial values ​​of the installation height z, pitch angle, and roll angle are: z = 0.4 m, pitch = 30°, and roll = 5°, respectively. The external parameter ranges for the installation height z, pitch angle, and roll angle are: delta_z = 0.05 m, delta_pitch = 5°, and delta_roll = 2°. The step interval is: step_z = 0.01 m, step_pitch = 0.5°, and step_roll = 0.2°. The step interval can be a cumulative step of step_z, a cumulative step of step_pitch, or a cumulative step of step_roll starting from the installation height z, without limitation. Continue to accumulate step intervals until the installation height z, pitch angle pitch, and roll angle roll have covered the corresponding extrinsic parameter ranges, that is, the test extrinsic parameter of the installation height z covers delta_z, the test extrinsic parameter of the pitch angle pitch covers delta_pitch, and the test extrinsic parameter of the roll angle roll covers delta_roll, thereby ending the accumulation and generating multiple sets of test extrinsic parameters. As a result, the laser radar has achieved traversal in the three extrinsic parameters of installation position z, pitch angle pitch, and roll angle roll, and can be applied to laser radars installed at various angles.

[0081] The generation module 210 may be further configured to execute steps S011 , S012 , and S013 , and the processor 10 may be further configured to execute steps S011 , S012 , and S013 .

[0082] See also Figures 7 to 9 In some embodiments, step S020 includes the steps of:

[0083] S021: Get the point cloud on the reference surface;

[0084] S022: filtering the point cloud that is blocked by the mounting carrier of the radar 40 to form a first point cloud D; and

[0085] S023: Calculate the height of the first point cloud D based on multiple sets of test external parameters to generate multiple sets of test heights.

[0086] In this embodiment, the point cloud on the reference surface is first obtained, and then the point cloud blocked by the mounting carrier of the radar 40 is filtered out to form a first point cloud D. Finally, the height of the first point cloud D is calculated based on multiple sets of test external parameters to generate multiple sets of test heights. If the point cloud is blocked by the mounting carrier, the point cloud used for calculation may be the point cloud on the mounting carrier, resulting in a large error. Therefore, filtering the point cloud blocked by the mounting carrier of the radar 40 in the point cloud can make the calculated test height more accurate.

[0087] Specifically, the radar 40 acquires a point cloud on the reference surface. If any of the acquired point clouds is blocked by the intelligent robot 100, for example Figure 7 The point cloud blocked by the intelligent robot 100 is the point cloud in the dotted box. The point cloud blocked by the intelligent robot 100 is filtered, that is, the point cloud in the dotted box is filtered out, and the remaining point cloud is the first point cloud D. If the acquired point cloud is not blocked by the mounting carrier of the radar 40, for example Figure 8 In the example, if the point cloud on the reference plane is not blocked by the intelligent robot 100, the obtained point cloud is the first point cloud D.

[0088] Furthermore, in one embodiment, the external parameters of the radar 40 that need to be calibrated are the installation height z, the pitch angle pitch, and the roll angle roll, wherein the coordinates of the point cloud in the radar 40 coordinate system are (x, y), wherein the installation height z, the pitch angle pitch, and the roll angle roll are the external parameters in the reference coordinate system, and in step S010, multiple groups of test external parameters are obtained, that is, multiple groups of combinations of installation height z, pitch angle pitch, and roll angle roll. Therefore, in step S020, the formula for calculating the reference height of the reference surface monitored by the radar 40 is h. The calculation formula is: h i =|z-xsin(pitch)+ycos(pitch)sin(roll)|, substitute z, pitch, and roll corresponding to multiple external parameters into the calculation formula for calculating the reference height h, so that multiple sets of test heights can be calculated by calculating the reference height.

[0089] The calculation module 220 may be further configured to execute steps S021 , S022 , and S023 , and the processor 10 may be further configured to execute steps S021 , S022 , and S023 .

[0090] See also Figures 10 to 12 In some embodiments, the radar 40 is capable of rotating about a rotation axis M relative to a mounting carrier of the radar 40 , and the extrinsic parameter calibration method further includes the steps of:

[0091] S001: setting an angle interval α according to the angle range of the radar 40 rotating around the rotation axis M to form a plurality of calibration areas X; and

[0092] S002: Perform at least one external parameter calibration for the radar 40 in each calibration area X

[0093] Specifically, using the intelligent robot 100 as an example, the installation position of the radar 40 on the intelligent robot 100 is not fixed. The external parameters of the radar 40 vary depending on the installation position. Therefore, calibration is required for the external parameters at each installation position. The radar 40 can rotate on the intelligent robot 100. The radar 40 can rotate about the center of the intelligent robot 100, where the center of the intelligent robot 100 serves as the rotation axis M. Alternatively, the radar 40 can rotate about a specific rotation axis on the intelligent robot 100, without limitation. An angular interval α is set based on the rotation angle range of the radar 40 about the rotation axis M, dividing the rotation angle range into multiple calibration areas X. The radar 40 then performs external parameter calibration at least once in each calibration area X, i.e., performing steps S010, S020, S030, S040, and S050 at least once.

[0094] First, an angular interval is set based on the angular range of the radar 40's rotation axis, dividing the range into multiple calibration zones. Finally, external parameter calibration is performed at least once within each calibration zone. This ensures that the radar 40 maintains appropriate external parameter acquisition data during rotation, facilitating obstacle avoidance, mapping, and other tasks. The angular interval can be set by the user based on the mechanical structure of the radar 40's mounting platform. The angular interval is constrained by the drive motor; smaller angular intervals place higher demands on the drive motor.

[0095] In one embodiment, please combine Figure 10 and Figure 11The radar 40 can rotate 360° around the rotation axis M, with an angular gap between [5°, 360°]. When the angular gap is 5°, the radar 40 needs to be calibrated at least a number of times, N = 360° / 5° = 72. When the angular gap is 360°, the radar 40 needs to be calibrated at least a number of times, N = 360° / 360° = 1. When the angular gap is less than 5°, the external parameters of the radar 40 do not change much when rotating through one angular gap. Furthermore, the smaller the angular gap, the more calculations are required when calculating the test height, which takes longer and reduces work efficiency. Therefore, an angular gap between [5°, 360°] can achieve better results while also requiring less calculations.

[0096] In one embodiment, the angular gap is 15°, the radar 40 is a laser radar, and the laser radar can rotate 360° around the rotation axis M. The laser radar needs to be calibrated at least N times = 360° / 15° = 24. Therefore, when the laser radar rotates around the rotation axis M, the calibration times are less and better external parameters can be obtained, which makes the calibration efficiency of the laser radar higher.

[0097] The external parameter calibration device 200 can also be used to execute step S001 and step S002, and the processor 10 can also be used to execute step S001 and step S002.

[0098] See also Figure 13 In some embodiments, the radar 40 is mounted on the intelligent robot 100, and the reference surface is the driving surface of the intelligent robot 100. Before executing step S020, that is, before executing "calculating the reference heights of the reference surface detected by the radar 40 based on multiple sets of test extrinsic parameters and generating multiple sets of test heights", the extrinsic parameter calibration method further includes:

[0099] Step S014: Control the intelligent robot 100 to move to a location within a preset range where there are no obstacles and the driving surface is flat.

[0100] Specifically, the reference plane is the driving surface of the intelligent robot 100, that is, the intelligent robot 100 is driving on the reference plane. At this time, the theoretical reference height of the reference plane should be zero. If the reference plane is the driving surface, if the driving surface is uneven, the reference height detected by the radar 40 will also be different, resulting in a large error in the final external parameter, affecting the radar 40's recognition of obstacles. Furthermore, if there is an obstacle within the preset range of the intelligent robot 100, the radar 40 may detect the reference height of the reference plane as the reference height of the obstacle, resulting in inaccurate external parameter results and the radar 40 cannot correctly identify obstacles in subsequent operations. Moving the intelligent robot 100 to a location within the preset range where there are no obstacles and the driving surface is flat can reduce the error in calculating the final external parameter, which is beneficial for the radar 40 to identify obstacles. The preset range can be a range set by the user or a range that can be detected by the radar 40, which is not limited here.

[0101] The external parameter calibration device 200 may also be used to execute step S014, and the processor 10 may also be used to execute step S014.

[0102] See also Figure 14 In some implementations, step S030 further includes:

[0103] Step S031: When the test height having the smallest difference from the reference height corresponds to multiple sets of test extrinsic parameters, the test extrinsic parameter of the test height obtained first is taken as the extrinsic parameter to be selected.

[0104] Specifically, the corresponding test heights can be calculated based on multiple sets of test external parameters. There may be cases where the test heights are the same, that is, one test height corresponds to multiple sets of test external parameters. In order to avoid differences in the external parameters of the radar 40 calibration caused by multiple sets of test external parameters, the test external parameters of the test height obtained for the first time are taken as the external parameters to be selected. In this way, the external parameter results of the radar 40 calibration are more accurate and the amount of calculation can be reduced.

[0105] The acquisition module 230 may be further configured to execute step S031 , and the processor 10 may be further configured to execute step S031 .

[0106] See also Figure 15 In some embodiments, when the output result of step S040 is no, execute

[0107] Step S051: If not, reset the external parameter range and / or step interval.

[0108] Specifically, when the output result of step S040 is no, that is, it is determined that the height difference between the test height corresponding to the selected external parameter and the reference height is not within the preset range, the external parameter range and / or the step interval is reset. It can be to reset the external parameter range, or to reset the step interval, or to reset the external parameter range and the step interval. By resetting the external parameter range and / or the step interval, when the radar 40 performs external parameter calibration again, it is more likely to obtain the appropriate external parameter.

[0109] In one embodiment, the extrinsic parameter range is: delta_z = 0.05m, delta_pitch = 5°, delta_roll = 2°, and the step interval is: step_z = 0.01m, step_pitch = 0.5°, step_roll = 0.2°. If no suitable extrinsic parameters are obtained within the extrinsic parameter range and step interval, at least one of delta_z, delta_pitch and delta_roll can be reduced or increased, or at least one of step_z, step_pitch and step_roll can be reduced or increased, or at least one of delta_z, delta_pitch and delta_roll can be reduced or increased and at least one of step_z, step_pitch and step_roll can be reduced or increased at the same time, so that the most suitable z, pitch and roll can be obtained in subsequent steps.

[0110] The determination module 250 may be further configured to execute step S051 , and the processor 10 may be further configured to execute step S051 .

[0111] Please refer again Figure 2 In some embodiments, the memory 20 is used to store a computer program that can be run on the processor 10, and when the processor 10 executes the program, the external parameter calibration method in any of the above embodiments is implemented.

[0112] The memory 20 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory. Furthermore, the intelligent robot 100 may also include a communication interface 30, which is used for communication between the memory 20 and the processor 10.

[0113] If the memory 20, processor 10, and communication interface 30 are implemented independently, the communication interface 30, memory 20, and processor 10 can be connected to each other via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 10 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0114] Optionally, in a specific implementation, if the memory 20, the processor 10 and the communication interface 30 are integrated on a chip, the memory 20, the processor 10 and the communication interface 30 can communicate with each other through an internal interface.

[0115] The processor 10 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0116] See also Figure 16 The non-volatile computer-readable storage medium 300 of an embodiment of the present application includes computer-executable instructions 301. When the computer-executable instructions are executed by one or more processors 400, the processor 400 executes the external parameter calibration method of any embodiment of the present application.

[0117] For example, when the computing executable instruction is executed by the processor 400, the processor 400 is configured to perform the steps:

[0118] S010: generating multiple groups of test external parameters at predetermined step intervals within a predetermined external parameter range;

[0119] S020: Calculating reference heights of reference surfaces detected by the radar 40 based on multiple sets of test external parameters, and generating multiple sets of test heights;

[0120] S030: obtaining, from among the multiple groups of test heights, a test extrinsic parameter corresponding to a test height having the smallest difference from a reference height as a candidate extrinsic parameter;

[0121] S040: Determine whether the height difference between the test height and the reference height corresponding to the selected external parameter is within a preset range; and

[0122] S050: If yes, determine that the external parameter to be selected is the external parameter after calibration of the radar 40.

[0123] A computer program is stored thereon, and when the program is executed by the processor 400, the above-mentioned external parameter calibration method is implemented.

[0124] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0125] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0126] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0127] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0128] In addition, the functional units in the various embodiments of the present application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The above-mentioned integrated module can be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. The above-mentioned storage medium can be a read-only memory, a magnetic disk or an optical disk, etc.

[0129] Throughout this specification, reference to the terms "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0130] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "plurality" means at least two, for example, two or three, unless otherwise specifically defined.

[0131] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A radar external parameter calibration method, characterized in that: The external parameter calibration method comprises: Generate multiple groups of test extrinsic parameters at predetermined step intervals within a predetermined extrinsic parameter range; Calculating the reference heights of the reference plane detected by the radar according to the multiple sets of test external parameters, and generating multiple sets of test heights; Obtaining, from the plurality of test heights, a test extrinsic parameter corresponding to a test height having the smallest difference with the reference height as a candidate extrinsic parameter; wherein the difference refers to the absolute value of the difference between the test height and the reference height; Determine whether the height difference between the test height corresponding to the selected external parameter and the reference height is within a preset range; and If so, determining that the to-be-selected external parameter is the radar calibrated external parameter; The step of calculating the reference heights of the reference plane detected by the radar based on the multiple sets of test external parameters and generating multiple sets of test heights includes: Acquire a point cloud on the reference plane; filtering point clouds blocked by the mounting carrier of the radar in the point cloud to form a first point cloud; and Calculating the heights of the first point cloud respectively according to the multiple sets of test extrinsic parameters to generate multiple sets of test heights; The radar is installed on the intelligent robot, and the reference surface is the driving surface of the intelligent robot. Before respectively calculating the reference heights of the reference surface detected by the radar based on the multiple sets of test extrinsic parameters and generating the multiple sets of test heights, the extrinsic parameter calibration method further includes: The intelligent robot is controlled to move to a position within a preset range where there are no obstacles and the driving surface is flat.

2. The external parameter calibration method according to claim 1, characterized in that The radar is capable of rotating about a rotation axis relative to a mounting carrier of the radar, and the external parameter calibration method further includes: Setting angle intervals according to the angle range of the radar rotation around the rotation axis to form a plurality of calibration areas; and Perform external parameter calibration for the radar at least once in each calibration area.

3. The external parameter calibration method according to claim 1, characterized in that The external parameters include the installation height, pitch angle and roll angle of the radar.

4. The external parameter calibration method according to claim 1, characterized in that The step of obtaining, from among the plurality of test heights, a test extrinsic parameter corresponding to a test height having the smallest difference from the reference height as a candidate extrinsic parameter, includes: When the test height having the smallest difference from the reference height corresponds to multiple sets of test extrinsic parameters, the test extrinsic parameter obtained for the first time for the test height is taken as the extrinsic parameter to be selected.

5. The external parameter calibration method according to claim 1, characterized in that: The external parameter calibration method also includes: When it is determined that the height difference between the test height corresponding to the to-be-selected external parameter and the reference height is not within a preset range, the external parameter range and / or the step interval are reset.

6. A radar external parameter calibration device, applied to an intelligent robot, characterized in that: The external parameter calibration device comprises: A generation module, the generation module is used to generate multiple groups of test extrinsic parameters at predetermined step intervals within a predetermined extrinsic parameter range; A calculation module, configured to calculate the reference heights of the reference plane detected by the radar according to the plurality of sets of test external parameters, and generate a plurality of sets of test heights; The step of calculating the reference heights of the reference plane detected by the radar based on the multiple sets of test external parameters and generating multiple sets of test heights includes: Acquire a point cloud on the reference plane; filtering point clouds blocked by the mounting carrier of the radar in the point cloud to form a first point cloud; and Calculate the height of the first point cloud according to multiple sets of test external parameters to generate multiple sets of test heights An acquisition module, the acquisition module being configured to acquire, as a candidate external parameter, a test extrinsic parameter corresponding to a test height having the smallest difference with the reference height among the plurality of test heights; wherein the difference refers to the absolute value of the difference between the test height and the reference height; A judgment module, configured to judge whether a height difference between a test height corresponding to the selected external parameter and the reference height is within a preset range; a determination module, configured to determine, when a result of the judgment module is yes, that the to-be-selected external parameter is the radar-calibrated external parameter; The radar is installed on the intelligent robot, and the reference surface is the driving surface of the intelligent robot. Before respectively calculating the reference heights of the reference surface detected by the radar based on the multiple sets of test extrinsic parameters and generating the multiple sets of test heights, the extrinsic parameter calibration method further includes: The intelligent robot is controlled to move to a position within a preset range where there are no obstacles and the driving surface is flat.

7. An intelligent robot, characterized in that: The intelligent robot comprises: One or more processors, memory; and One or more programs, wherein the one or more programs are stored in the memory and executed by the one or more processors, and the programs include instructions for executing the external parameter calibration method according to any one of claims 1 to 5.

8. A non-volatile computer-readable storage medium containing computer-executable instructions, which, when executed by one or more processors, causes the processors to execute the extrinsic parameter calibration method according to any one of claims 1 to 5.

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