Laser calibration method, laser calibration device and computer storage medium

Abstract

The invention provides a laser calibration method, a laser calibration device and a computer storage medium. The laser calibration method is applied to laser external parameter calibration of a single-steering-wheel vehicle body model. The laser calibration method comprises the following steps: issuing a linear control sequence to the single-steering-wheel vehicle body model; obtaining a first odometer pose transformation sequence and a first laser coordinate system pose transformation sequence which are solved under the control of the linear control sequence; according to the first speedometer pose change sequence, obtaining a first vehicle body movement track calculated by the speedometer; acquiring a second vehicle body movement track observed by laser according to the first laser coordinate system pose transformation sequence; and solving a yaw angle of the laser extrinsic parameter according to a rotation transformation relation between the first vehicle body motion trail and the second vehicle body motion trail. By means of the laser calibration method, laser dynamic calibration of a single-steering-wheel vehicle type is achieved.

Description

Technical Field

[0001] This application relates to the field of sensor calibration technology, and in particular to a laser calibration method, a laser calibration device, and a computer storage medium. Background Technology

[0002] With the continuous evolution of sensor technology and indoor 2D SLAM (simultaneous localization and mapping) technology, sensor fusion technology is gradually emerging as a major trend in robot mapping and localization research. Robots achieve high-precision mapping and localization of their surroundings by fusing data from multiple sensors and establishing constraints between the data. However, when robots use wheel encoders for assisted mapping and localization, factors such as mechanical manufacturing and installation errors, as well as tire deformation, slippage, and wear caused by prolonged robot operation, can lead to slight changes in the internal and external parameters of the odometer. These slight changes significantly affect the robot's mapping and localization performance, thus requiring regular parameter calibration to ensure the accuracy and stability of mapping and localization.

[0003] For mobile robots, errors caused by wear and tear during factory assembly and long-term use are unavoidable in determining the laser parameters mounted on the mobile laser. Manual calibration is often inefficient and inaccurate. Summary of the Invention

[0004] To address the aforementioned technical problems, this application proposes a laser calibration method, a laser calibration device, and a computer storage medium.

[0005] To address the aforementioned technical problems, this application proposes a laser calibration method. This laser calibration method is applied to the laser extrinsic parameter calibration of a single steering wheel vehicle body model. The laser calibration method includes: Send a linear control sequence to the single-steering wheel vehicle model; Obtain the first odometer pose transformation sequence and the first laser coordinate system pose transformation sequence solved under the linear control sequence; The first vehicle body motion trajectory calculated by the odometer is obtained based on the first odometer pose change sequence. The second vehicle motion trajectory observed by laser is obtained based on the pose transformation sequence of the first laser coordinate system. Based on the rotational transformation relationship between the first vehicle trajectory and the second vehicle trajectory, the yaw angle of the laser extrinsic parameters is calculated.

[0006] The laser calibration method further includes, after solving for the yaw angle of the laser extrinsic parameters: Send arc control sequences with different steering wheel angles to the single steering wheel vehicle model; Obtain the second odometry pose transformation sequence and the second laser coordinate system pose transformation sequence obtained under the control of the arc control sequence; By combining the second odometry pose transformation sequence and the second laser coordinate system pose transformation sequence, a set of translation constraint equations is obtained; wherein, the set of translation constraint equations includes the yaw angle of the laser extrinsic parameters; The offset of the laser extrinsic parameters is obtained by solving the translation constraint equations.

[0007] The step of obtaining the offset of the laser extrinsic parameters by solving the translation constraint equations includes: The translation constraint equations are converted into a matrix equation system. The matrix equations are solved using the least squares method to obtain the extrinsic translation vector. The X-direction offset and Y-direction offset of the laser extrinsic parameters are determined based on the elements of the extrinsic parameter translation vector.

[0008] Before issuing the arc control sequence with different steering wheel angles to the single steering wheel vehicle model, the laser calibration method further includes: Obtain the zero-bias value of the steering wheel corresponding to the different steering wheel angles; The single-steering wheel vehicle model is compensated based on the zero bias value of the steering wheel at different steering wheel angles.

[0009] The step of obtaining the second odometry pose transformation sequence and the second laser coordinate system pose transformation sequence obtained under the control of the arc control sequence includes: Obtain the vehicle's linear velocity and angular velocity over a period of time under the control of the arc control sequence; The change in vehicle angle is determined based on the vehicle body angular velocity and the control time. The change in vehicle position is determined based on the change in vehicle angle, the length of control time, and the linear velocity of the vehicle. The change in vehicle body rotation is determined based on the change in vehicle body angle; The vehicle body posture change is determined based on the vehicle body position change and the vehicle body rotation change; Based on the vehicle body pose change, solve for the second odometer pose transformation sequence; Obtain the laser point cloud over a period of time under the control of the arc control sequence; The second laser coordinate system pose transformation sequence is obtained by solving the laser coordinate system pose transformation between two adjacent frames of laser point clouds.

[0010] Before issuing the linear control sequence to the single-steering wheel vehicle model, the laser calibration method further includes: Obtain the zero bias value of the steering wheel when the steering wheel angle is 0; The single-steering wheel vehicle model is compensated based on the zero bias value of the steering wheel.

[0011] The step of compensating the single-steering-wheel vehicle model based on the zero-bias value of the steering wheel includes: The single-steering wheel zero bias value is compensated for by a microcontroller through a zero bias setting interface on the single-steering wheel vehicle model.

[0012] The zero bias value of the steering wheel is obtained by calculating the steering wheel angle measurement value using a non-constant value function.

[0013] To address the aforementioned technical problems, this application also proposes a laser calibration device, which includes a memory and a processor coupled to the memory; wherein the memory is used to store program data, and the processor is used to execute the program data to implement the laser calibration method as described above.

[0014] To address the aforementioned technical problems, this application also proposes a computer storage medium for storing program data, which, when executed by a computer, is used to implement the aforementioned laser calibration method.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: the laser calibration device guides the single-steering wheel vehicle model to run in a straight line by issuing a linear control sequence, so that only linear control is used when calibrating the laser extrinsic angle, ensuring the accuracy of the laser extrinsic angle calculation; due to the linear control operation, the vehicle motion trajectory calculated by the odometer and the vehicle motion trajectory observed by the laser differ only by a rotation transformation. Based on this hand-eye calibration principle, the yaw angle of the laser extrinsic can be directly solved, effectively simplifying the laser calibration process and improving calibration efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic flowchart of an embodiment of the laser calibration method provided in this application; Figure 2 This is a schematic diagram of the structure of an embodiment of the single-steering wheel vehicle body model provided in this application; Figure 3This is a schematic diagram of the single-steering wheel vehicle motion model provided in this application; Figure 4 This is a schematic flowchart of another embodiment of the laser calibration method provided in this application; Figure 5 This is a scene diagram of the hand-eye calibration constraint model provided in this application; Figure 6 This is a schematic diagram of an embodiment of the laser calibration device provided in this application; Figure 7 This is a schematic diagram of the structure of an embodiment of the computer storage medium provided in this application. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0018] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] This application proposes a laser dynamic calibration method for single-steering wheel vehicle models. The main calibration object, i.e. the solution variable, is the laser extrinsic parameter, including but not limited to: the x-direction offset x of the laser extrinsic parameter, the y-direction offset y of the laser extrinsic parameter, and the yaw angle yaw of the laser extrinsic parameter.

[0020] It should be noted that the laser type calibrated in this application is a 2D laser. The actual external parameters of the laser relative to the vehicle body should be 6-dimensional. Since the laser tilt angle has been verified before the laser dynamic calibration in this application, it is assumed that the laser roll angle and pitch angle are almost strictly 0. Therefore, the external parameters of the laser to be calibrated are reduced from the original six-dimensional to a three-dimensional form.

[0021] Please refer to the details. Figure 1, Figure 1 This is a schematic flowchart of an embodiment of the laser calibration method provided in this application.

[0022] The laser calibration method of this application is applied to a laser calibration device, which can be a server, a terminal device, or a system in which the server and the terminal device cooperate with each other. Accordingly, the various parts of the laser calibration device, such as each unit, subunit, module, and submodule, can all be set in the server, all in the terminal device, or separately in the server and the terminal device.

[0023] Furthermore, the aforementioned server can be either hardware or software. When the server is hardware, it can be implemented as a distributed server cluster consisting of multiple servers, or as a single server. When the server is software, it can be implemented as multiple software programs or software modules, such as software or software modules used to provide distributed server functionality, or as a single software program or software module; no specific limitations are made here.

[0024] It should be noted that the laser calibration device in this application can be a mobile robot equipped with a laser calibration function module, i.e., a single-steering wheel vehicle.

[0025] like Figure 1 As shown, the specific steps are as follows: Step S11: Send a linear control sequence to the single-steering wheel vehicle model.

[0026] In this embodiment of the application, the laser calibration device sends a linear control sequence to the single steering wheel vehicle model to control the single steering wheel vehicle to run in a straight line, thereby obtaining data for solving the laser angle.

[0027] Specifically, please refer to the single-steering wheel vehicle model studied in this application. Figure 2 , Figure 2 This is a schematic diagram of the structure of an embodiment of the single-steering wheel vehicle body model provided in this application.

[0028] like Figure 2 As shown, solid arrows indicate the X and Y directions of the vehicle coordinate system, while dashed arrows indicate the X and Y directions of the laser coordinate system. The positive X-axis of the vehicle coordinate system points towards the front of the vehicle. The front wheels of the chassis are single steering wheels, capable of both driving and steering. The two rear wheels of the chassis are fixed follower wheels, lacking driving and steering capabilities. In this application, it is assumed that the zero bias of the two rear fixed follower wheels is strictly zero, and that the coordinates of the three wheels in the vehicle coordinate system are known quantities.

[0029] Before issuing the linear control sequence, the laser calibration device can also perform odometer calibration on the single steering wheel vehicle to obtain relevant calibration parameters.

[0030] Specifically, assuming that the zero-bias of the steering wheel has been obtained through odometer calibration for steering wheel angles of 0 degrees, +90 degrees, and -90 degrees, the zero-bias of the steering wheel at any steering wheel angle can be obtained through linear interpolation. The zero-bias value of the steering wheel corresponding to a steering wheel angle of 0 degrees is compensated through the zero-bias setting interface, and an open-loop straight-line travel command is issued to the single-steering-wheel vehicle.

[0031] It should be noted that since the steering wheel angle in this straight path has been compensated through the zero-bias setting interface, the observed steering wheel angle value is directly used as the true value of the steering wheel angle for odometer calculation.

[0032] In this application, zero-bias setting interface technology is used in the odometer calibration process. The zero bias of the steering wheel is compensated by a single-chip microcomputer, so that the zero bias of the steering wheel does not need to be manually compensated during each odometer calculation.

[0033] In conventional zero-bias models, the zero bias of the steering wheel is often modeled as a constant, meaning that regardless of how the steering wheel angle changes, the zero bias remains constant.

[0034]

[0035] in, This represents the true value of the steering wheel angle. The measured value of the steering wheel angle is calculated using an angle encoder. For zero deflection of the steering wheel, It is a constant.

[0036] Through relevant experiments, the staff of this application discovered a correlation between the zero-bias ratio of the steering wheel and the measured steering wheel angle, namely:

[0037]

[0038] in, It is a very value function.

[0039] In one specific implementation, to simplify model calculations, this application may further modify the functional relationship. Model it as a piecewise linear function, that is:

[0040] in, , , , All are constants.

[0041] Step S12: Obtain the first odometer pose transformation sequence and the first laser coordinate system pose transformation sequence solved under linear control sequence.

[0042] In this embodiment of the application, when the single steering wheel vehicle is running in a straight line, the laser calibration device collects encoder data and laser data through various sensors on the single steering wheel vehicle, timestamps the two data, and solves the odometer pose transformation sequence and the laser coordinate system pose transformation sequence.

[0043] Specifically, this application proposes an odometer model and uses closed-loop integration to solve the odometer pose transformation sequence.

[0044] Known in linear velocity of the vehicle body within a time interval and angular velocity .

[0045] Changes in vehicle body angle over time .

[0046] The changes in the vehicle's position over time are as follows:

[0047] Vehicle body position change over time for:

[0048] in, .

[0049] The data used to solve the odometer pose transformation sequence is: vehicle linear velocity. and angular velocity This can be achieved by inputting encoder data as follows: Figure 3 The single steering wheel vehicle motion model shown is used for forward kinematic modeling.

[0050] Specifically, given the measured values ​​of the steering wheel drive speed, steering wheel angle, steering wheel radius, and steering wheel wheelbase, the linear velocity and angular velocity of the chassis are calculated based on kinematics.

[0051] The forward kinematic model is as follows:

[0052]

[0053]

[0054]

[0055] in, The rotational speed is calculated from the value of the steering wheel speed encoder. The radius of the steering wheel, The steering wheel angle measurement value is calculated from the front wheel angle encoder value. Wheelbase For zero deflection of the steering wheel, This represents the functional relationship between the zero bias of the steering wheel and the steering wheel angle.

[0056] Regarding the solution of the laser coordinate system pose transformation sequence, this application adopts the laser matching (2d-ICP) method to solve the pose transformation of the laser coordinate system between two frames of laser point clouds, thereby obtaining the pose transformation sequence of the laser coordinate system.

[0057] Step S13: Obtain the first vehicle body motion trajectory calculated by the odometer based on the first odometer pose change sequence.

[0058] Step S14: Obtain the second vehicle body motion trajectory observed by laser based on the pose transformation sequence of the first laser coordinate system.

[0059] In this embodiment, the laser calibration device obtains the first vehicle motion trajectory calculated by the odometer based on the first odometer pose change sequence, and obtains the second vehicle motion trajectory observed by the laser based on the first laser coordinate system pose transformation sequence. The calculation method can be as follows: the vehicle pose and laser pose at each moment are obtained as trajectory points based on the pose change sequence; then, the trajectory points are fitted and sorted according to time sequence through motion trajectory fitting to obtain the corresponding motion trajectory.

[0060] Step S15: Solve for the yaw angle of the laser extrinsic parameters according to the rotational transformation relationship between the first vehicle trajectory and the second vehicle trajectory.

[0061] In this embodiment, according to the definition of zero yaw of the steering wheel, it can be known that the actual angle of the steering wheel is strictly 0 at this time. Therefore, the vehicle trajectory calculated by the odometer and the vehicle trajectory observed by the laser differ only by a rotation transformation. The laser calibration device can solve for the laser angle, i.e., the yaw angle, using the following formula:

[0062] in, This represents the x-direction component of the pose transformation vector in the laser coordinate system. The y-direction component represents the pose transformation vector of the laser coordinate system. This represents the x-direction component of the pose transformation vector in the vehicle coordinate system. This represents the y-direction component of the pose change vector in the vehicle coordinate system.

[0063] In this application, the calibration device guides the single-steering wheel vehicle model to run along a straight line by issuing a linear control sequence. This ensures that only linear control is used when calibrating the laser extrinsic angle, guaranteeing the accuracy of the laser extrinsic angle calculation. Due to the linear control operation, the vehicle trajectory calculated by the odometer and the vehicle trajectory observed by the laser differ only by a rotation transformation. Based on this hand-eye calibration principle, the yaw angle of the laser extrinsic can be directly solved, effectively simplifying the laser calibration process and improving calibration efficiency.

[0064] based on Figure 1 The calculated yaw angle of the laser extrinsic parameters can also be used to calibrate the offset of the laser extrinsic parameters. Please refer to the following for details. Figure 4 , Figure 4 This is a schematic flowchart of another embodiment of the laser calibration method provided in this application.

[0065] like Figure 4 As shown, the specific steps are as follows: Step S21: Send arc control sequences with different steering wheel angles to the single steering wheel vehicle model.

[0066] In this embodiment of the application, the laser calibration device sends an arc control sequence to the single steering wheel vehicle model to control the single steering wheel vehicle to run in an arc direction, thereby obtaining data for solving the laser offset.

[0067] It should be noted that before issuing the arc control sequence, the laser calibration device can also calculate the required zero offset using interpolation and compensate for the zero offset value of the single steering wheel vehicle model through the zero offset setting interface. The steering wheel zero offset value can be calculated based on the zero offset model provided in this application combined with encoder data, or it can be calculated using interpolation based on the currently calculated steering wheel zero offset value.

[0068] Step S22: Obtain the second odometry pose transformation sequence and the second laser coordinate system pose transformation sequence obtained under the control of the arc control sequence.

[0069] In this embodiment of the application, the process of solving the pose transformation sequence is basically the same as the process of step S12 above, and will not be described again here.

[0070] Step S23: Combine the second odometry pose transformation sequence and the second laser coordinate system pose transformation sequence to obtain the translation constraint equation set; wherein, the translation constraint equation set includes the yaw angle of the laser extrinsic parameters.

[0071] In this embodiment, the laser calibration device primarily solves for the laser offset using the theory of a hand-eye calibration constraint model. Therefore, the hand-eye calibration constraint model involved in this application is introduced below: Please refer to the details. Figure 5 , Figure 5 This is a scene diagram of the hand-eye calibration constraint model provided in this application.

[0072] like Figure 5 As shown, let O be the vehicle coordinate system, L be the laser coordinate system, the subscripts indicate the time corresponding to the coordinate system, X be the transformation matrix from the vehicle coordinate system to the laser coordinate system, A be the transformation matrix from the vehicle coordinate system at time t to the vehicle coordinate system at time t+1, and B be the transformation matrix from the laser coordinate system at time t to the laser coordinate system at time t+1. Then, the transformation matrix from the vehicle coordinate system at time t to the laser coordinate system at time t+1 can be represented in two ways, and they are equal:

[0073] Expanding the above equation yields the following form:

[0074] Where R is the rotation matrix component corresponding to the transformation matrix, t is the translation vector component corresponding to the transformation matrix, and the subscript corresponds to the transformation matrix.

[0075] Expanding the above equation further, we get the following form:

[0076]

[0077] The two equations above are called the rotational and translational constraints of hand-eye calibration, respectively.

[0078] Since the two-dimensional rotation matrix is ​​commutative with respect to matrix multiplication, the rotation constraint degenerates into:

[0079] Translation constraints can be simplified to the following form:

[0080] If the rotational transformation from the vehicle coordinate system at time t to the vehicle coordinate system at time t+1 is not an identity matrix (i.e., the angle of the vehicle in the world coordinate system has changed, which can be achieved by having the vehicle travel along an arc), then it can be proven that in the two-dimensional case, It is at full capacity, at this time There is a unique solution. Furthermore, if the rotation transformation has already been solved, then we can obtain:

[0081] In practical applications, to ensure the robustness of the solution, this application can collect multiple sets of arc walking data from different angles and use the least squares method to solve the problem. The closed-form solution.

[0082] Based on the hand-eye calibration constraint model described above, the laser calibration device can combine the pose transformation sequence of the laser coordinate system and the odometry pose transformation sequence to obtain a series of translation constraints:

[0083] The first superscript k indicates that this transformation occurs from timestamp k to k+1, and the second superscript... This indicates that the angle of the steering wheel during this transformation is .

[0084] To simplify the notation, the steering wheel angles corresponding to the arc paths are all integers after conversion to degrees (e.g., 0 degrees, 5 degrees, 10 degrees, etc.). The remaining notations maintain the same correspondence as above.

[0085] Furthermore, by combining the above translation constraints, we obtain the following system of translation constraint equations:

[0086] Step S24: Obtain the offset of the laser extrinsic parameters by solving the translation constraint equations.

[0087] In this embodiment of the application, the laser calibration device denotes the matrix within the left square brackets in the translation constraint equation set as... The vector within the right square brackets is denoted as The problem then becomes solving the following system of matrix equations:

[0088] Based on the derivation of the hand-eye calibration constraint condition in step S23, when the arc control sequence is issued, the rotation matrix corresponding to the laser coordinate system pose transformation matrix must not be equal to the identity matrix. Since the system of equations is of full rank, it has at most a unique solution.

[0089] And because The number of rows is much greater than 2, therefore this is an overdetermined system of equations. The solution then becomes finding the least-squares solution to the system, i.e.:

[0090] Therefore:

[0091]

[0092] Where x is the X-direction offset of the laser extrinsic parameter, and y is the Y-direction offset of the laser extrinsic parameter.

[0093] Specifically, matrix Each line is a "Issuing the arc control sequence" means that the robot's base coordinate system has undergone a real rotation, that is... (The rotation matrix is ​​not equal to the identity matrix).

[0094] when At that time, matrix The null space dimension is smaller than that of the translation vector. The dimension ensures that when there are multiple sets of data with different rotations, these... The matrix formed by stacking It is full rank in terms of columns. Full rank in terms of columns means that the matrix... The column vectors are linearly independent, and the unknowns are... The components are not mixed together and cannot be distinguished, thus ensuring that the problem is theoretically "solvable".

[0095] Furthermore, the laser calibration device obtains the vector by solving the aforementioned overdetermined system of equations. It represents the coordinates of the origin of the lidar coordinate system in the robot base coordinate system, i.e., the extrinsic translation vector.

[0096] Representing vectors The first element. This element is defined as the x-component of the laser extrinsic parameters, that is, the X-direction offset of the lidar in the base coordinate system.

[0097] Representing vectors The second element. This element is defined as the y-component of the laser extrinsic parameters, that is, the Y-direction offset of the lidar in the base coordinate system.

[0098] Those skilled in the art will understand that, in the above-described method of the specific implementation, the order in which each step is written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of each step should be determined by its function and possible internal logic.

[0099] To implement the above-mentioned laser calibration method, this application also proposes a laser calibration device, for details please refer to [link / reference needed]. Figure 6 , Figure 6 This is a schematic diagram of an embodiment of the laser calibration device provided in this application.

[0100] The laser calibration device 400 in this embodiment includes a processor 41, a memory 42, an input / output device 43, and a bus 44.

[0101] The processor 41, memory 42, and input / output device 43 are respectively connected to the bus 44. The memory 42 stores program data, and the processor 41 is used to execute the program data to implement the laser calibration method described in the above embodiments.

[0102] In this embodiment, processor 41 can also be referred to as a CPU (Central Processing Unit). Processor 41 may be an integrated circuit chip with signal processing capabilities. Processor 41 can also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor, or processor 41 can be any conventional processor.

[0103] This application also provides a computer storage medium; please refer to the following: Figure 7 , Figure 7 This is a schematic diagram of a computer storage medium according to an embodiment of the present application. The computer storage medium 600 stores a computer program 61, which, when executed by a processor, is used to implement the laser calibration method of the above embodiment.

[0104] When the embodiments of this application are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0105] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method of laser calibration, characterized by, The laser calibration method is applied to laser extrinsic parameter calibration of a single rudder wheel vehicle model, and the laser calibration method comprises the following steps: a straight line control sequence is issued to the single rudder wheel vehicle model; a first odometer pose transformation sequence and a first laser coordinate system pose transformation sequence are obtained by solving under the control of the straight line control sequence; a first vehicle motion trajectory calculated by an odometer is obtained according to the first odometer pose transformation sequence; a second vehicle motion trajectory observed by a laser is obtained according to the first laser coordinate system pose transformation sequence; a yaw angle of the laser extrinsic parameter is solved according to the rotational transformation relationship between the first vehicle motion trajectory and the second vehicle motion trajectory.

2. The laser calibration method of claim 1, wherein after the yaw angle of the laser extrinsic parameter is solved, the laser calibration method further comprises the following steps: an arc control sequence with different rudder wheel angles is issued to the single rudder wheel vehicle model; a second odometer pose transformation sequence and a second laser coordinate system pose transformation sequence are obtained by solving under the control of the arc control sequence; a translation constraint equation set is obtained by combining the second odometer pose transformation sequence and the second laser coordinate system pose transformation sequence; wherein the translation constraint equation set comprises the yaw angle of the laser extrinsic parameter; a displacement of the laser extrinsic parameter is solved by the translation constraint equation set.

3. The laser calibration method of claim 2, wherein the displacement of the laser extrinsic parameter is solved by the translation constraint equation set, comprising the following steps: the translation constraint equation set is converted into a matrix equation set; an extrinsic parameter translation vector is obtained by solving the matrix equation set using a least square method; X-direction and Y-direction displacements of the laser extrinsic parameter are determined according to elements of the extrinsic parameter translation vector.

4. The laser calibration method of claim 2, wherein before the arc control sequence with different rudder wheel angles is issued to the single rudder wheel vehicle model, the laser calibration method further comprises the following steps: rudder wheel zero offset values corresponding to different rudder wheel angles are obtained; the single rudder wheel vehicle model is compensated according to the rudder wheel zero offset values of different rudder wheel angles.

5. The laser calibration method of claim 2, wherein the second odometer pose transformation sequence and the second laser coordinate system pose transformation sequence obtained by solving under the control of the arc control sequence, comprising the following steps: vehicle linear velocity and vehicle angular velocity within a period of time under the control of the arc control sequence are obtained; vehicle angular change is determined according to the vehicle angular velocity and control time length; vehicle position change is determined according to the vehicle angular change, the control time length and the vehicle linear velocity; vehicle rotation change is determined according to the vehicle angular change; vehicle pose change is determined according to the vehicle position change and the vehicle rotation change; the second odometer pose transformation sequence is solved according to the vehicle pose change; laser point clouds within a period of time under the control of the arc control sequence are obtained; the second laser coordinate system pose transformation sequence is solved by solving laser coordinate system pose transformations between two adjacent frames of laser point clouds. ​ ​ ​ ​ 6.The laser calibration method of claim 1, wherein, before the laser calibration method issuing the straight line control sequence to the single rudder wheel vehicle model, the laser calibration method further comprises: acquiring a rudder wheel zero offset value when the rudder wheel angle is 0; compensating the single rudder wheel vehicle model according to the rudder wheel zero offset value. 7.The laser calibration method of claim 6, wherein, the compensating the single rudder wheel vehicle model according to the rudder wheel zero offset value comprises: compensating the single rudder wheel vehicle model for the rudder wheel zero offset value by a single chip microcomputer through a zero offset setting interface. 8.The laser calibration method of claim 6, wherein, the rudder wheel zero offset value is obtained by operating a rudder wheel angle measurement value through a very value function.

9. A laser calibration apparatus characterized by comprising: the laser calibration device comprises a memory and a processor coupled with the memory; wherein the memory is configured to store program data, and the processor is configured to execute the program data to implement the laser calibration method of any one of claims 1 to 8.

10. A computer storage medium, characterized in that, the computer storage medium is configured to store program data, and the program data, when executed by a computer, is configured to implement the laser calibration method of any one of claims 1 to 8.

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