Method, system and equipment for determining initial angle of steering wheel and medium

Abstract

The invention discloses a method, a system and equipment for determining an initial angle of a steering wheel and a medium, and belongs to the technical field of automatic control technologies. The method for determining the initial angle of the steering wheel comprises the steps that after the mower is started, the mower is controlled to move at a constant speed in a steering wheel locking state; according to the positioning data, determining an actual movement track of the mower in a uniform-speed movement process, selecting N position points from the actual movement track according to a fixed step length, and determining a relative course angle when the mower is located at each position point; selecting a plurality of point pairs meeting a distance constraint condition from all the position points; setting the horizontal distance between the mounting point of the positioning module and the center of the front wheel axle as a reference distance; the turning radius corresponding to the first type of position points in each position point is calculated; and calculating the initial angle of the steering wheel according to the turning radiuses of all the first-class position points and the reference distance. The initial angle of the steering wheel can be accurately detected.

Description

Technical Field

[0001] This application relates to the field of automatic control technology, and in particular to a method, system, device and medium for determining the initial angle of a steering wheel. Background Technology

[0002] Some lawnmowers require a steering wheel control method based on a relative position mode. This control method relies on the steering wheel's initial angle (also known as the initial position angle) to achieve precise directional control. However, whenever the lawnmower is powered off and then powered on again, it cannot automatically obtain the steering wheel's initial angle, thus affecting control accuracy.

[0003] Therefore, how to accurately detect the initial angle of the steering wheel is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this application is to provide a method, system, device, and medium for determining the initial angle of a steering wheel, which can accurately detect the initial angle of the steering wheel.

[0005] To solve the above-mentioned technical problems, this application provides a method for determining the initial angle of a steering wheel, comprising:

[0006] After the lawnmower is started, it is controlled to move at a constant speed while the steering wheel is locked; wherein, the steering wheel is locked means that the angle of the steering wheel remains unchanged.

[0007] The actual trajectory of the lawnmower during uniform motion is determined based on the positioning data. N position points are selected from the actual trajectory with a fixed step size, and the relative heading angle of the lawnmower at each of the position points is determined. The positioning data is collected by a positioning module installed on the lawnmower, and the actual trajectory is used to describe the positional changes of the installation point of the positioning module.

[0008] Multiple point pairs satisfying distance constraints are selected from all the said location points; wherein each point pair includes one first-type location point and one second-type location point; the distance constraint is: the distance between the first-type location point and the second-type location point is greater than a preset distance, and the preset distance is greater than the fixed step size; in the same point pair, the time point when the lawnmower passes the first-type location point is earlier than the time point when the lawnmower passes the second-type location point;

[0009] The horizontal distance between the mounting point of the positioning module and the center of the front wheel axle is set as the reference distance;

[0010] Calculate the turning radius corresponding to each of the first type of position points based on the relative heading angle of the first type of position points, the relative heading angle of the second type of position points, the position coordinates of the first type of position points, and the position coordinates of the second type of position points;

[0011] The initial angle of the steering wheel is calculated based on the turning radius of all the first type of position points and the reference distance.

[0012] Optionally, based on the relative heading angle of the first type of location point, the relative heading angle of the second type of location point, the position coordinates of the first type of location point, and the position coordinates of the second type of location point, the turning radius corresponding to each of the first type of location points is calculated, including:

[0013] Substituting the relative heading angle of the first type of position point, the relative heading angle of the second type of position point, the position coordinates of the first type of position point, and the position coordinates of the second type of position point into the radius calculation formula, we obtain the turning radius corresponding to each first type of position point. ;

[0014] The formula for calculating the radius is as follows: , The X-axis coordinates of the first type of location points are represented. This represents the Y-axis coordinate of the first type of location point. This represents the X-axis coordinate of the second type of location point. This represents the Y-axis coordinate of the second type of location point. This represents the relative heading angle of the first type of location point. This represents the relative heading angle of a second type of location point.

[0015] Optionally, the initial angle of the steering wheel is calculated based on the turning radius of all the first type of position points and the reference distance, including:

[0016] Calculate the steering angle of the first type of position point based on the turning radius and the reference distance;

[0017] The average value of the steering angles of all the first type of position points is set as the initial angle of the steering wheel.

[0018] Optionally, calculating the steering angle of the first type of position point based on the turning radius and the reference distance includes:

[0019] The turning radius Substituting the reference distance L into the angle calculation formula, the turning angle of the first type of position point is obtained. ;

[0020] The formula for calculating the angle is as follows: .

[0021] Optionally, before determining the actual trajectory of the lawnmower during its uniform motion based on the positioning data, the method further includes:

[0022] A navigation coordinate system is established with the positioning base station corresponding to the positioning module as the origin;

[0023] The rear wheel axle center is determined based on the structural parameters of the lawnmower, and a carrier coordinate system is established with the rear wheel axle center as the origin.

[0024] Determine the coordinate transformation matrix between the navigation coordinate system and the vehicle coordinate system;

[0025] Determine the relative position of the antenna installation position of the positioning module with respect to the center of the rear wheel axle, and calculate the positioning correction parameters based on the relative position and the coordinate system transformation matrix;

[0026] The positioning data collected by the positioning module is corrected using the positioning correction parameters.

[0027] Optionally, before determining the actual trajectory of the lawnmower during its uniform motion based on the positioning data, the method further includes:

[0028] The system determines whether the lawnmower is moving at a constant speed based on the data detected by the wheel speed meter.

[0029] If so, the positioning module and the inertial measurement unit are controlled to synchronously perform data acquisition operations according to a preset cycle; wherein, the attitude data acquired by the inertial measurement unit is used to calculate the relative heading angle.

[0030] Optionally, after calculating the initial angle of the steering wheel based on the turning radius of all the first type of location points and the reference distance, the method further includes:

[0031] Release the steering wheel lock of the lawnmower to enable motion control of the lawnmower based on the initial angle of the steering wheel;

[0032] If a power-off command is received, the steering wheel is rotated to a preset angle to perform a power-off operation.

[0033] This application also provides a steering wheel initial angle determination system, the system comprising:

[0034] The motion control module is used to control the lawnmower to move at a constant speed while the steering wheel is locked after the lawnmower is started; wherein, the steering wheel is locked means that the angle of the steering wheel remains unchanged.

[0035] The trajectory analysis module is used to determine the actual motion trajectory of the lawnmower during uniform motion based on the positioning data, select N position points from the actual motion trajectory according to a fixed step size, and determine the relative heading angle of the lawnmower at each of the position points; wherein, the positioning data is collected by the positioning module installed on the lawnmower, and the actual motion trajectory is used to describe the positional changes of the installation point of the positioning module;

[0036] The point pair selection module is used to select multiple point pairs that satisfy distance constraints from all the location points; wherein each point pair includes one first-type location point and one second-type location point; the distance constraint is that the distance between the first-type location point and the second-type location point is greater than a preset distance, and the preset distance is greater than a fixed step size; in the same point pair, the time when the lawnmower passes the first-type location point is earlier than the time when the lawnmower passes the second-type location point.

[0037] The distance setting module is used to set the horizontal distance between the mounting point of the positioning module and the center of the front wheel axle as a reference distance;

[0038] The radius calculation module is used to calculate the turning radius corresponding to each of the first type of position points based on the relative heading angle of the first type of position points, the relative heading angle of the second type of position points, the position coordinates of the first type of position points, and the position coordinates of the second type of position points.

[0039] An angle calculation module is used to calculate the initial angle of the steering wheel based on the turning radius of all the first type of position points and the reference distance.

[0040] This application also provides a storage medium storing a computer program thereon, which, when executed, implements the steps of the above-described method for determining the initial angle of the steering wheel.

[0041] This application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor, when calling the computer program in the memory, implements the steps of the above-described method for determining the initial angle of the steering wheel.

[0042] This application provides a method for determining the initial angle of a steering wheel. After the lawnmower is started, the method controls the lawnmower to move at a constant speed while the steering wheel is locked, and determines the actual trajectory of the lawnmower during this constant speed movement based on positioning data. This application selects N position points from the actual trajectory and determines the relative heading angle of the lawnmower at each of these position points. This application selects point pairs that satisfy distance constraints from all position points, and then determines the corresponding turning radius based on the relative heading angle and position coordinates of each point pair. This allows for the calculation of the initial angle of the steering wheel based on the horizontal distance between the mounting point of the positioning module and the center of the front wheel axle, and the aforementioned turning radius. The above process considers the turning radii of multiple first-type position points and reference distances to comprehensively calculate the initial angle of the steering wheel, enabling accurate detection of the initial angle. This application also provides a steering wheel initial angle determination system, a storage medium, and an electronic device, all possessing the aforementioned beneficial effects, which will not be elaborated upon here. Attached Figure Description

[0043] To more clearly illustrate the embodiments of this application, the accompanying drawings used in 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.

[0044] Figure 1 A flowchart illustrating a method for determining the initial angle of a steering wheel, provided in an embodiment of this application;

[0045] Figure 2 A schematic diagram of the structural composition of a lawnmower provided in an embodiment of this application;

[0046] Figure 3 A top view of a lawnmower provided in an embodiment of this application;

[0047] Figure 4 A schematic diagram of a location point provided in an embodiment of this application;

[0048] Figure 5 A motion analysis diagram of a lawnmower provided in an embodiment of this application;

[0049] Figure 6 This is a simplified diagram of the motion analysis of a lawnmower provided in an embodiment of this application. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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 some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0051] Please see below. Figure 1 , Figure 1 This is a flowchart illustrating a method for determining the initial angle of a steering wheel, as provided in an embodiment of this application.

[0052] Specific steps may include:

[0053] S101: After the lawnmower is started, control the lawnmower to move at a constant speed while the steering wheel is locked;

[0054] This embodiment can be applied to the control module of a lawnmower, which may also include a wheel speed sensor, an inertial measurement unit, and a positioning module. Specifically, the positioning module is a GNSS positioning module. The initial angle determined in this embodiment is the steering wheel angle when the lawnmower starts, that is, the steering wheel angle of the lawnmower in its initial position.

[0055] After the lawnmower is started, this step can lock the steering angle of the lawnmower so that the lawnmower is in a steering wheel locked state, where the steering wheel angle remains unchanged.

[0056] After the lawnmower is in the steering wheel locked state, it can be controlled to move at a constant speed in the steering wheel locked state.

[0057] S102: Determine the actual motion trajectory of the lawnmower during uniform motion based on the positioning data, select N position points from the actual motion trajectory according to a fixed step size, and determine the relative heading angle of the lawnmower at each of the position points.

[0058] During the lawnmower's uniform motion, positioning data can be collected using a positioning module, and attitude data can be collected using an inertial measurement unit.

[0059] This step determines the actual trajectory of the lawnmower during its uniform motion based on the positioning data. The positioning data is collected by a positioning module installed on the lawnmower, and the actual trajectory describes the positional changes of the positioning module's mounting point; for example, the mounting point of the positioning module can be the center of the lawnmower's rear axle (i.e., the center point of the vehicle's rear axle).

[0060] After determining the actual trajectory of the lawnmower during its uniform motion, this step involves selecting N position points from the actual trajectory using a fixed step size. The distance between any two adjacent position points is the fixed step size. In this embodiment, i can be used to represent the position point number; the smaller the position number, the earlier the lawnmower passes by the point. The distance between the i-th position point and the (i+1)-th position point is equal to the fixed step size, where 0 < i ≤ N.

[0061] After selecting N location points, the relative heading angle of the lawnmower at each of the aforementioned location points can be determined. The relative heading angle is determined based on attitude data collected by the inertial measurement unit; the relative heading angle refers to the change in heading obtained by integrating the angular velocity measured by the inertial measurement unit over time, representing the orientation deflection angle of the current moment relative to a specific moment (such as the initial moment or the previous moment).

[0062] S103: Select multiple pairs of points that satisfy the distance constraint from all the said location points.

[0063] Based on the determined N location points, multiple point pairs satisfying distance constraints can be selected from all the location points. Each point pair includes one first-type location point and one second-type location point. The distance constraints are as follows: the distance between the first-type location point and the second-type location point is greater than a preset distance, and the preset distance is greater than a fixed step size; within the same point pair, the time when the lawnmower passes the first-type location point is earlier than the time when the lawnmower passes the second-type location point.

[0064] S104: Set the horizontal distance between the mounting point of the positioning module and the center of the front wheel axle as the reference distance;

[0065] In this embodiment, the horizontal distance between the installation point of the positioning module and the center of the front wheel axle can be determined based on the structural parameters of the lawnmower, and the horizontal distance between the installation point of the positioning module and the center of the front wheel axle can be set as a reference distance.

[0066] S105: Calculate the turning radius corresponding to each of the first type of position points based on the relative heading angle of the first type of position point, the relative heading angle of the second type of position point, the position coordinates of the first type of position point, and the position coordinates of the second type of position point.

[0067] This step, based on the position coordinates of the first and second type of position points and their respective relative heading angles, constructs the local trajectory geometry of the lawnmower within this movement segment. By determining the chord using the coordinates of two points and combining it with the two heading angles (i.e., the tangent direction of the trajectory), the curvature center of the circular motion when the lawnmower passes the first type of position point is deduced using the principle of circular arc fitting or the geometric method of three points determining a circle, and then the turning radius of the corresponding first type of position point is calculated.

[0068] S106: Calculate the initial angle of the steering wheel based on the turning radius of all the first type of position points and the reference distance.

[0069] In this step, the initial angle of the steering wheel can be determined by using geometric relationships based on the turning radius of each first-type position point and the reference distance between the positioning module and the vehicle motion reference point, combined with the vehicle kinematic model.

[0070] In this embodiment, after the lawnmower is started, it is controlled to move at a constant speed while the steering wheel is locked, and the actual trajectory of the lawnmower during the constant speed movement is determined based on positioning data. This embodiment selects N position points from the actual trajectory and determines the relative heading angle of the lawnmower at each of these position points. This embodiment selects point pairs that satisfy distance constraints from all position points, and then determines the corresponding turning radius based on the relative heading angle and position coordinates of each point pair. This allows for the calculation of the initial steering wheel angle based on the horizontal distance between the mounting point of the positioning module and the center of the front wheel axle, and the aforementioned turning radius. The above process considers the turning radii of multiple first-type position points and reference distances to comprehensively calculate the initial steering wheel angle, enabling accurate detection of the initial steering wheel angle.

[0071] As for Figure 1 A further description of the corresponding embodiment, the process of calculating the turning radius corresponding to each of the first type of position points based on the relative heading angle of the first type of position points, the relative heading angle of the second type of position points, the position coordinates of the first type of position points, and the position coordinates of the second type of position points includes:

[0072] Substituting the relative heading angle of the first type of position point, the relative heading angle of the second type of position point, the position coordinates of the first type of position point, and the position coordinates of the second type of position point into the radius calculation formula, we obtain the turning radius corresponding to each first type of position point. ;

[0073] The formula for calculating the radius is as follows: , The X-axis coordinates of the first type of location points are represented. This represents the Y-axis coordinate of the first type of location point. This represents the X-axis coordinate of the second type of location point. This represents the Y-axis coordinate of the second type of location point. This represents the relative heading angle of the first type of location point. This represents the relative heading angle of a second type of location point.

[0074] As for Figure 1A further description of the corresponding embodiment involves calculating the initial angle of the steering wheel based on the turning radius of all the first type of position points and the reference distance, including: calculating the steering angle of the first type of position points based on the turning radius and the reference distance; and setting the average value of the steering angles of all the first type of position points as the initial angle of the steering wheel.

[0075] The above process calculates the corresponding steering angle based on the turning radius and reference distance of each first-type position point using vehicle kinematics; the arithmetic mean of the steering angles obtained from all first-type position points is taken, and this average value is used as the initial angle of the steering wheel.

[0076] Specifically, the process of calculating the steering angle of the first type of position point based on the turning radius and the reference distance includes: setting the turning radius... Substituting the reference distance L into the angle calculation formula, the turning angle of the first type of position point is obtained. ;

[0077] The formula for calculating the angle is as follows: .

[0078] As for Figure 1 In a further description of the corresponding embodiment, before determining the actual trajectory of the lawnmower during uniform motion based on the positioning data, it is also possible to determine whether the lawnmower is in a uniform motion state based on the data detected by the wheel speed meter; if so, the positioning module and the inertial measurement unit are controlled to synchronously perform data acquisition operations according to a preset cycle; wherein, the attitude data collected by the inertial measurement unit is used to calculate the relative heading angle. The above operations ensure that the collected data corresponds to a stable motion condition, so as to accurately detect the initial angle of the steering wheel.

[0079] Furthermore, after calculating the initial angle of the steering wheel based on the turning radii of all the first type of position points and the reference distance, the steering wheel of the lawnmower can be unlocked to allow for motion control of the lawnmower based on the initial angle of the steering wheel. If a power-off command is received, the steering wheel is rotated to a preset angle to perform a power-off operation. The above operations ensure that the mechanical position is known when power is restored next time.

[0080] The embodiments provided in this application are all based on the accuracy of the positioning data detected by the positioning module. However, since the antenna of the positioning module is installed at a certain distance from the body of the lawnmower, if the positioning data collected by the positioning module is used directly when the lawnmower is on a slope, positioning errors will occur. Therefore, before determining the actual movement trajectory of the lawnmower during uniform motion based on the positioning data, the following data correction operations for the positioning module can be performed:

[0081] A navigation coordinate system is established with the positioning base station corresponding to the positioning module as the origin; the rear wheel axle center is determined according to the structural parameters of the lawnmower, and a carrier coordinate system is established with the rear wheel axle center as the origin; the coordinate system transformation matrix between the navigation coordinate system and the carrier coordinate system is determined; the relative positional relationship between the antenna installation position of the positioning module and the rear wheel axle center is determined, and positioning correction parameters are calculated according to the relative positional relationship and the coordinate system transformation matrix; the positioning correction parameters are used to correct the positioning data collected by the positioning module.

[0082] The process described in the above embodiments is illustrated below through examples in practical applications.

[0083] The lawnmower in this embodiment can be an automatic lawnmower, that is, an automated gardening device that can complete the mowing operation without human intervention. The positioning methods used by the lawnmower include RTK (Real-Time Kinematic) technology, visual SLAM (Simultaneous Localization and Mapping) technology, and laser SLAM technology.

[0084] Currently, lawnmowers are mainly controlled by differential speed control and steering wheel control.

[0085] Differential control works by controlling the speed difference between the left and right drive wheels, ensuring that the inner wheel rotates slower than the outer wheel, thus reducing centrifugal force and preventing rollover. Advantages of differential control include: adaptability to different road conditions and maintaining driving stability; high driving efficiency and the ability to achieve zero-turnover. Disadvantages of differential control include: needing to compensate for distance differences through different speeds, resulting in higher energy consumption compared to traditional mechanical steering; and a more complex control system with higher maintenance costs.

[0086] Steering wheel control amplifies steering force through a hydraulic power assist system or mechanical transmission, allowing precise control of the lawnmower's direction by turning the steering wheel. Advantages of steering wheel control include: direct steering control via the steering wheels, eliminating the need for complex system adjustments; and a simple, reliable, and low-maintenance traditional mechanical structure. Disadvantages of steering wheel control include: potential for sideslip in high-speed sharp turns or complex road conditions; control precision affected by tire wear and road conditions; and the traditional mechanical structure experiencing greater wear and tear, resulting in a larger turning radius and reduced driving efficiency.

[0087] Steering wheel control typically employs two modes: absolute position control and relative position control. Absolute position control provides accurate absolute position information, but requires an absolute position encoder, which is costly. Furthermore, prolonged operation can lead to wear and tear on the steering mechanism, resulting in significant steering angle errors and necessitating recalibration. Relative position control is relatively cheaper, but the initial steering wheel angle position information is lost each time the lawnmower is powered off and on again, requiring calibration to obtain it.

[0088] To address the technical problems existing in the aforementioned related technologies, this embodiment provides a method for calibrating the initial angle of a lawnmower's steering wheel, which can solve the problem that the initial position angle information of the lawnmower's steering wheel cannot be obtained each time the lawnmower is powered off and then powered on again due to the use of a relative position control method.

[0089] In this embodiment, the lawnmower employs a steering wheel control method based on a relative position mode, requiring the acquisition of the initial steering wheel angle information. Since RTK (Real-Time Kinematic) positioning is used, it can provide centimeter-level accuracy position data for the automatic lawnmower; the IMU module can provide accurate attitude angle information. Therefore, the initial steering wheel angle of the lawnmower can be obtained by combining the position point data provided by the GNSS positioning module and the attitude angle data provided by the IMU module, along with the geometric relationship between the position data, attitude angle data, and steering wheel position angle.

[0090] The implementation process of the above-mentioned lawnmower steering wheel initial angle calibration method includes: establishing a global geodetic coordinate system with the coordinates of the positioning base station as the origin; converting the lawnmower positioning data into coordinates under the global coordinate system; after the lawnmower's automatic task is started, the control module controls the lawnmower to travel at a low and constant speed; collecting the position coordinates of positions 1, 2, ..., N and the heading angle measurement values ​​of the IMU module at intervals of a first distance threshold; sequentially, at intervals of a second threshold distance, calculating the initial angle of the lawnmower steering wheel through the poses of positions 1 and M, positions 2 and M+1, ..., positions h and N; and calculating the average value of the initial steering wheel angle as the initial angle of the lawnmower steering wheel.

[0091] Please see Figure 2 , Figure 2 This is a schematic diagram of the structural composition of a lawnmower provided in an embodiment of this application; Figure 2 As shown, the lawnmower provided in this embodiment includes: a GNSS positioning module 201, an IMU (Inertial Measurement Unit) module 202, a wheel speed meter 203, a control module 204, and an actuator 205.

[0092] The aforementioned GNSS positioning module provides location data, speed data, and positioning status to the lawnmower's control module. The location data is the east, north, and celestial position in a geographic coordinate system with the base station as the origin; the speed data is the east, north, and celestial speed in the geographic coordinate system; the positioning status includes: "0" corresponding to "positioning unavailable," "1" corresponding to "single-point positioning," "2" corresponding to "RTK floating-point solution," and "3" corresponding to "RTK fixed solution."

[0093] The aforementioned IMU module is used to provide the control module with the relative heading angle, pitch angle, and roll angle.

[0094] The aforementioned wheel speed gauge is used to provide the linear speed of travel to the control module.

[0095] The aforementioned control module is used to send speed control commands to the actuator, and can also perform tasks such as task scheduling, speed calibration, and obtaining the linear speed of the wheel speed meter.

[0096] The aforementioned actuator is used to receive and execute the driving speed sent by the control module.

[0097] Specifically, the initial angle calibration process for the lawnmower's steering wheel provided in this embodiment includes the following steps:

[0098] Step A1: Establish a global navigation coordinate system with the coordinates of the positioning base station as the origin. The The navigation coordinate system is: the Northeast Sky Coordinate System (hereinafter referred to as the "Northeast Sky Coordinate System") with the GNSS base station as the origin. The east coordinate X is the eastward position under the geographic coordinate system with the base station as the origin; the north coordinate Y is the northward position under the geographic coordinate system with the base station as the origin; and the north coordinate Z is the skyward position under the geographic coordinate system with the base station as the origin.

[0099] Furthermore, this embodiment can use the latitude and longitude coordinates of the positioning base station in the WGS84 coordinate system. Coordinates converted to navigation coordinate system by Gauss-Krüger projection The latitude and longitude coordinates provided by the GNSS positioning module are converted into navigation coordinates after being projected into Gauss-Krüger coordinates. Then, the base station coordinates are subtracted, and the resulting coordinates are converted into coordinates in the global navigation coordinate system OXY with the positioning base station coordinates as the origin.

[0100] Please see Figure 3 , Figure 3 This is a top view of a lawnmower provided in an embodiment of this application. O represents a GNSS positioning base station, OB is the center of the rear wheel axle (i.e., the installation position of the IMU module and GNSS antenna), OD is the center of the front wheel axle, W1 represents the front wheel, W2 represents the rear wheel, L represents the horizontal distance between the center of the rear wheel axle and the center of the front wheel axle, and B represents the wheel track of the rear wheel.

[0101] The coordinate system OXYZ is a navigation coordinate system with the GNSS base station as the origin, namely the northeast-sky coordinate system. The east coordinate X is the eastward position in the geographic coordinate system with the base station as the origin; the north coordinate Y is the northward position in the geographic coordinate system with the base station as the origin; and the Z coordinate (not shown in the figure) is the sky position in the geographic coordinate system with the base station as the origin.

[0102] Step A2: Obtain the antenna positioning data and positioning status of the GNSS module, and convert the positioning data into coordinates in the global coordinate system;

[0103] The GNSS module is a single GNSS antenna, and it is installed at the center OB of the rear wheel track of the lawnmower.

[0104] The above positioning data refers to the location data at the installation position of the GNSS antenna; the positioning status refers to the positioning status provided by the GNSS module, including: positioning unavailable, single-point positioning, RTK floating-point solution, and RTK fixed solution.

[0105] Specifically, this embodiment can be implemented in the state of RTK fixed solution. When the GNSS module's positioning state is in the state of RTK fixed solution, the position coordinates in the global coordinate system are... for:

[0106] ;

[0107] in, The coordinate data in the WGS84 coordinate system at time i. Coordinates after Gauss-Kruger projection; during automatic lawnmower operation, the control module uses horizontal coordinates. .

[0108] Step A3: After the lawnmower's automatic task is started, the control module controls the lawnmower to operate at low speed. During driving, the heading angle is initialized based on the positioning data from the GNSS single-antenna positioning module and the heading angle from the IMU module.

[0109] The IMU module is installed at the center of the rear wheel axle of the lawnmower (i.e., the center of the rear wheel track) OB.

[0110] Please see Figure 4 , Figure 4This is a schematic diagram of location points provided in an embodiment of this application. The diagram shows N location points: 1, 2, 3, 4, ..., h, M, M+1, M+2, ..., N. The black curve in the diagram represents the movement trajectory of the lawnmower, the black dots represent the current location of the lawnmower, and the numbers represent the indices of the corresponding location points. The distance between adjacent location points is greater than a first distance threshold. The distance between location point 1 and location point M, location point 2 and location point M+1, ..., location point h and location point N is greater than a second distance threshold. In this embodiment, the first set of initial heading angles can be calculated based on location point 1 and location point M, the second set of initial heading angles can be calculated based on location point 2 and location point M+1, and the h-th set of initial heading angles can be calculated based on location point h and location point N.

[0111] Please see Figure 5 , Figure 5 This is a motion analysis diagram of a lawnmower provided in an embodiment of this application. W1 represents the front wheel (steering wheel), W2 represents the rear wheel (drive wheel), OD represents the center of the front wheel axle (i.e., the center point of the front wheel track), OB represents the center of the rear wheel axle, and L is the distance between the center of the rear wheel axle and the center of the front wheel axle. This indicates the direction of the lawnmower's movement. The initial angle of the lawnmower's steering wheel is given. The distance between position point 1 and position point M is greater than the second distance threshold. The IMU module and GNSS positioning module are installed at the center OB of the rear wheel axle. R is the turning radius of the lawnmower. Let O represent the turning angle of the lawnmower from position 1 to position M, where O denotes the turning center. This represents the change in the heading angle measured by the IMU module as the lawnmower moves from position 1 to position M.

[0112] The detailed process for initial steering wheel angle calibration is as follows:

[0113] Step B1: After the lawnmower's automatic task is started, the initial angle of the lawnmower's steering wheel is locked (remains unchanged) to ensure that the lawnmower moves in an approximately circular arc.

[0114] Step B2: The control module controls the lawnmower to travel at a low speed. When the speed reaches... The lawnmower travels at a constant speed.

[0115] Step B3: Record the position coordinates of the i-th location point of the lawnmower at intervals of the first distance threshold. The relative heading angle provided by the IMU module Data, pose data Store it in a vector;

[0116] Step B4: When the vector length reaches Stop recording when the time is right;

[0117] Step B5: From pose In the process, the initial steering wheel angles of two position points with a second distance threshold as the interval are calculated sequentially;

[0118] The detailed calculation process for step B5 is as follows:

[0119] Starting from the first location point, select locations whose distance from the first location point is greater than the second distance threshold. The pose of the Mth position point and the 1st position point is The pose of the Mth position point is ;

[0120] In the case of short time and short distance, the motion from point 1 to point M can be considered as a circular arc (a straight line can also be a circular arc with a large radius).

[0121] Please see Figure 6 , Figure 6 This is a simplified motion analysis diagram of a lawnmower provided in an embodiment of this application. The diagram shows the motion trajectory from position point 1 to position point M. Indicates the direction of the lawnmower's movement. This represents the change in the heading angle measured by the IMU module as the lawnmower moves from position 1 to position M. This represents the angle between the direction of the lawnmower at position 1 and the direction from position 1 to position M. R represents the angle between the direction of the lawnmower at position M and the direction from position 1 to position M, and R represents the turning radius of the lawnmower. This represents the turning angle of the lawnmower from position 1 to position M, where O' represents the turning center. Here, L is the initial angle of the lawnmower's steering wheel, L is the distance between the center of the rear axle and the center of the front axle, and P is the midpoint between position point 1 and position point M. OD represents the center of the front axle (i.e., the center point of the front wheel track), and OB represents the center of the rear axle.

[0122] The direction from position 1 to position M. This represents the change in the heading angle measured by the IMU module as the lawnmower moves from position 1 to position M. The direction of the lawnmower at position 1 and The angle between directions The direction of the lawnmower at position point M is... The angle between the directions, the distance between position point 1 and position point M is greater than the second distance threshold, and R is the turning radius of the lawnmower. Given the turning angle of the lawnmower from position 1 to position M, we can obtain:

[0123] ;

[0124] In the formula, This is the heading angle measurement value from the IMU module at the first position point. The heading angle measurement value of the IMU module at the Mth position point;

[0125] OM and OB are both turning radii with length R, and the direction of the lawnmower's movement is tangent to the turning radius. From geometric relationships, we can deduce that:

[0126] ;

[0127] Furthermore, since point P is the midpoint between point 1 and point M, we can obtain:

[0128] ;

[0129] The distance from point 1 to point P is The calculation is as follows:

[0130] ;

[0131] Furthermore, since the direction of movement of the lawnmower at position 1 is tangent to the turning radius, we can obtain:

[0132] ;

[0133] Furthermore, the turning radius R of the lawnmower at position 1 can be obtained, calculated as follows:

[0134] ;

[0135] Substituting into the formula, we get:

[0136] ;

[0137] Furthermore, since the front wheels of the lawnmower are steering wheels, the direction of rotation of the front wheels is related to the turning radius. Tangent, therefore, in a right triangle From this, we can obtain:

[0138] ;

[0139] in, This is the initial angle value of the steering wheel.

[0140] Furthermore, in right triangle DOB, the length of side BD is the distance L from the control center B to the center D of the front wheel, and the length of side OB is the radius of curvature R. Therefore, we can obtain... The calculation formula is as follows:

[0141] ;

[0142] Furthermore, the initial steering wheel angle calculated from the poses of position points 1 and 3 is: The calculation is as follows:

[0143] ;

[0144] Similarly, starting from the second position, select positions whose distance to the second position is greater than the second distance threshold. The pose of the (M+1)th position point and the second position point is The pose of the (M+1)th position is The second position point corresponds to the initial steering wheel angle at the (M+1)th position point. The calculation is as follows:

[0145] ;

[0146] In sequence, starting from the h-th position point, corresponding to the last position point N in the vector, the pose of the h-th position point is... The pose of the Nth position is The initial steering wheel angle at position h corresponds to position N. The calculation is as follows:

[0147] ;

[0148] The average value of the initial angle of the lawnmower steering wheel is calculated as follows: ,as follows:

[0149] h = N - M + 1;

[0150] In the formula, The initial steering wheel angle is calculated for the i-th position point.

[0151] This embodiment provides a method for calibrating the initial angle of a lawnmower's steering wheel, solving the problem that, due to the relative position control method, the initial position angle information of the lawnmower's steering wheel cannot be obtained each time the power is cut off and restarted. During the lawnmower's automatic operation, the initial steering wheel angle is calibrated online without requiring the lawnmower to be stopped or human intervention.

[0152] The following is a positioning data correction scheme when the slope of the lawnmower location is 0 degrees and the antenna installation position is directly above the center of the rear wheel axle:

[0153] In the context of automatic lawnmower operation, RTK positioning is used. Factors such as multipath effects caused by obstruction from buildings and trees, electromagnetic interference, and signal transmission delays caused by the ionosphere and troposphere can all lead to reduced positioning accuracy or positioning failure. Furthermore, the GNSS antenna's installation location and the surrounding environment (such as metal structures and strong magnetic fields) can directly affect signal reception quality, causing a decrease in positioning accuracy. Therefore, if the GNSS antenna is installed too low on the lawnmower, it is easily obstructed by the lawnmower's structure and susceptible to electromagnetic interference from power components (such as the engine, generator, and battery) or electronic devices during operation.

[0154] To avoid obstruction and electromagnetic interference from the lawnmower's structure, the GNSS antenna is typically installed at the highest point of the machine, at a certain distance from the body. However, in actual working scenarios, lawnmowers often operate on uneven ground such as slopes and potholes. The position coordinates provided by the GNSS positioning module are the horizontal coordinates of the antenna installation location. Due to the influence of slopes and potholes, the position coordinates provided by the GNSS module deviate significantly from the actual control position of the lawnmower (for example, if the GNSS antenna is installed at a height of 1.5m and a tilt angle of 15°, the horizontal position error can reach 0.388m). This results in repeated mowing or missed mowing during automatic tasks, requiring manual intervention to correct the missed areas and impacting the user experience.

[0155] Based on the problems existing in the above-mentioned related technologies, this embodiment provides a lawnmower position correction scheme, which can eliminate the influence of slopes and potholes on the positioning module and solve the problem that there is a large deviation between the position coordinates provided by the GNSS positioning module and the actual position of the lawnmower.

[0156] The purpose of this embodiment is to solve the problem that the position coordinates provided by the GNSS positioning module deviate significantly from the actual control position of the lawnmower due to the influence of slopes and potholes, so as to provide high-precision positioning for the actual control center of the lawnmower and reduce the missed mowing rate and repetition rate of the lawnmower's automatic tasks.

[0157] This embodiment establishes a global geodetic coordinate system with the coordinates of the positioning base station as the origin. After the lawnmower's automatic task is started, the control module controls the lawnmower to travel at low speed. The heading angle is initialized based on the positioning data from the GNSS positioning module and the heading angle from the IMU module. The current heading angle is calculated by combining the position data from the GNSS module and the heading angle from the IMU module. The roll angle and pitch angle provided by the IMU module are used to calculate the transformation matrix from the navigation coordinate system to the carrier coordinate system. The transformation matrix from the navigation coordinate system to the carrier coordinate system is transposed to obtain the transformation matrix from the carrier coordinate system to the navigation coordinate system. The height difference between the GNSS antenna position and the lawnmower control position, combined with the transformation matrix from the carrier coordinate system to the navigation coordinate system, is used to calculate the corrected position coordinates of the lawnmower control center.

[0158] Specifically, the above-mentioned lawnmower position correction scheme includes the following steps:

[0159] Step B1: Establish a global navigation coordinate system with the coordinates of the positioning base station as the origin. The The navigation coordinate system is: a northeast-sky coordinate system with the GNSS base station as the origin; the east coordinate X is the eastward position in the geographic coordinate system with the base station as the origin; the north coordinate Y is the northward position in the geographic coordinate system with the base station as the origin; and the north coordinate Z is the sky-sky position in the geographic coordinate system with the base station as the origin.

[0160] Furthermore, this step can convert the latitude and longitude coordinates of the positioning base station into the WGS84 (a global geodetic coordinate system) coordinate system. Coordinates converted to navigation coordinate system by Gauss-Krüger projection The latitude and longitude coordinates provided by the GNSS positioning module are converted into navigation coordinates after being projected into Gauss-Krüger coordinates. Then, the base station coordinates are subtracted, and the resulting coordinates are converted into coordinates in the global navigation coordinate system OXY with the positioning base station coordinates as the origin.

[0161] Step B2: Obtain the antenna positioning data and positioning status of the GNSS module, and convert the positioning data into coordinates in the global coordinate system.

[0162] The aforementioned GNSS positioning module uses a single GNSS antenna and is installed at the center of the lawnmower's rear wheel axle (also known as the rear wheel center). The rear wheel axle center is the midpoint of the line connecting the centers of the left and right rear wheels.

[0163] The above positioning data refers to the location data at the installation position of the GNSS antenna; the positioning status refers to the positioning status provided by the GNSS module, including: positioning unavailable, single-point positioning, RTK floating-point solution, and RTK fixed solution.

[0164] Specifically, this embodiment can be implemented in the state of RTK fixed solution. When the GNSS module's positioning state is in the state of RTK fixed solution, the position coordinates in the global coordinate system are... for:

[0165] ;

[0166] in, The coordinate data in the WGS84 coordinate system at time i. Coordinates after Gauss-Kruger projection; during automatic lawnmower operation, the control module uses horizontal coordinates. .

[0167] Step B3: After the lawnmower's automatic task is started, the control module controls the lawnmower to travel at a low speed and completes the heading angle initialization based on the positioning data from the GNSS positioning module and the heading angle from the IMU module.

[0168] The IMU module is installed at the center of the rear wheel axle of the lawnmower.

[0169] Step B4: The height difference between the GNSS antenna installation position and the position of the rear axle center (also known as the lawnmower control position) is: The current heading angle is obtained by combining the position data from the GNSS positioning module and the heading angle from the IMU module. The roll angle provided by the IMU module and pitch angle The coordinate transformation matrix from the carrier coordinate system to the navigation coordinate system is calculated, and the position data provided by the GNSS module is corrected to obtain the coordinates of the lawnmower's control position.

[0170] Furthermore, the calculation process for the transformation matrix from the vehicle coordinate system to the navigation coordinate system is as follows:

[0171] This embodiment can establish a carrier coordinate system for the lawnmower with the rear axle center as the origin. The navigation coordinate system is The navigation coordinate system can be aligned with the carrier coordinate system after three rotations. The rotation sequence is as follows: rotation around the Z-axis by the heading angle. Pitch angle around the X-axis and the roll angle around the Y-axis .

[0172] Navigation coordinate system rotates around the Z-axis rotation matrix as follows:

[0173] .

[0174] The navigation coordinate system then rotates around the X-axis rotation matrix as follows:

[0175] .

[0176] The navigation coordinate system then rotates around the Y-axis rotation matrix as follows:

[0177] .

[0178] Transformation matrix from navigation coordinate system to vehicle coordinate system as follows:

[0179] ;

[0180] Furthermore, the transformation matrix from the navigation coordinate system to the vehicle coordinate system... Transpose the coordinates to obtain the coordinate transformation matrix from the vehicle coordinate system to the navigation coordinate system. ,as follows:

[0181] ;

[0182] The height difference between the GNSS antenna mounting position and the center position of the rear axle is The GNSS antenna installation position in the carrier coordinate system is represented as follows: The correction amount in the navigation coordinate system is .

[0183] Therefore, we can conclude that: T indicates transpose.

[0184] Furthermore, the correction amount in the navigation coordinate system can be calculated. :

[0185] .

[0186] GNSS antenna installation location After correction, the position coordinates of the lawnmower control center were obtained. :

[0187] .

[0188] The aforementioned lawnmower position correction method solves the problem of significant deviations between the position coordinates provided by the GNSS positioning module and the actual control position of the lawnmower due to the influence of slopes and potholes. It provides high-precision positioning for the actual control center of the lawnmower, reducing the missed mowing rate and repetition rate of automatic lawnmower tasks. This method allows for online correction during automatic lawnmower tasks, eliminating the need to stop the lawnmower or require manual intervention.

[0189] This application provides an embodiment of a steering wheel initial angle determination system, comprising:

[0190] The motion control module is used to control the lawnmower to move at a constant speed while the steering wheel is locked after the lawnmower is started; wherein, the steering wheel is locked means that the angle of the steering wheel remains unchanged.

[0191] The trajectory analysis module is used to determine the actual motion trajectory of the lawnmower during uniform motion based on the positioning data, select N position points from the actual motion trajectory according to a fixed step size, and determine the relative heading angle of the lawnmower at each of the position points; wherein, the positioning data is collected by the positioning module installed on the lawnmower, and the actual motion trajectory is used to describe the positional changes of the installation point of the positioning module;

[0192] The point pair selection module is used to select multiple point pairs that satisfy distance constraints from all the location points; wherein each point pair includes one first-type location point and one second-type location point; the distance constraint is that the distance between the first-type location point and the second-type location point is greater than a preset distance, and the preset distance is greater than a fixed step size; in the same point pair, the time when the lawnmower passes the first-type location point is earlier than the time when the lawnmower passes the second-type location point.

[0193] The distance setting module is used to set the horizontal distance between the mounting point of the positioning module and the center of the front wheel axle as a reference distance;

[0194] The radius calculation module is used to calculate the turning radius corresponding to each of the first type of position points based on the relative heading angle of the first type of position points, the relative heading angle of the second type of position points, the position coordinates of the first type of position points, and the position coordinates of the second type of position points.

[0195] An angle calculation module is used to calculate the initial angle of the steering wheel based on the turning radius of all the first type of position points and the reference distance.

[0196] In this embodiment, after the lawnmower is started, it is controlled to move at a constant speed while the steering wheel is locked, and the actual trajectory of the lawnmower during the constant speed movement is determined based on positioning data. This embodiment selects N position points from the actual trajectory and determines the relative heading angle of the lawnmower at each of these position points. This embodiment selects point pairs that satisfy distance constraints from all position points, and then determines the corresponding turning radius based on the relative heading angle and position coordinates of each point pair. This allows for the calculation of the initial steering wheel angle based on the horizontal distance between the mounting point of the positioning module and the center of the front wheel axle, and the aforementioned turning radius. The above process considers the turning radii of multiple first-type position points and reference distances to comprehensively calculate the initial steering wheel angle, enabling accurate detection of the initial steering wheel angle.

[0197] Furthermore, the radius calculation module calculates the turning radius corresponding to each of the first type of position points based on the relative heading angles of the first type of position points, the relative heading angles of the second type of position points, the position coordinates of the first type of position points, and the position coordinates of the second type of position points. The process includes:

[0198] Substituting the relative heading angle of the first type of position point, the relative heading angle of the second type of position point, the position coordinates of the first type of position point, and the position coordinates of the second type of position point into the radius calculation formula, we obtain the turning radius corresponding to each first type of position point. ;

[0199] The formula for calculating the radius is as follows: , The X-axis coordinates of the first type of location points are represented. This represents the Y-axis coordinate of the first type of location point. This represents the X-axis coordinate of the second type of location point. This represents the Y-axis coordinate of the second type of location point. This represents the relative heading angle of the first type of location point. This represents the relative heading angle of a second type of location point.

[0200] Furthermore, the process by which the angle calculation module calculates the initial angle of the steering wheel based on the turning radius of all the first type of position points and the reference distance includes: calculating the steering angle of the first type of position points based on the turning radius and the reference distance;

[0201] The average value of the steering angles of all the first type of position points is set as the initial angle of the steering wheel.

[0202] Furthermore, the process by which the angle calculation module calculates the steering angle of the first type of position point based on the turning radius and the reference distance includes: [The process involves] calculating the turning radius... Substituting the reference distance L into the angle calculation formula, the turning angle of the first type of position point is obtained. ;

[0203] The formula for calculating the angle is as follows: .

[0204] Furthermore, it also includes:

[0205] The positioning correction module is used to establish a navigation coordinate system with the positioning base station corresponding to the positioning module as the origin before determining the actual movement trajectory of the lawnmower during uniform motion based on the positioning data; it is also used to determine the rear wheel axle center based on the structural parameters of the lawnmower and establish a carrier coordinate system with the rear wheel axle center as the origin; it is also used to determine the coordinate system transformation matrix between the navigation coordinate system and the carrier coordinate system; it is also used to determine the relative positional relationship between the antenna installation position of the positioning module and the rear wheel axle center, and calculate positioning correction parameters based on the relative positional relationship and the coordinate system transformation matrix; and it is also used to correct the positioning data collected by the positioning module using the positioning correction parameters.

[0206] Furthermore, it also includes:

[0207] The status judgment module is used to determine whether the lawnmower is in a uniform motion state based on the data detected by the wheel speed meter before determining the actual motion trajectory of the lawnmower during uniform motion based on the positioning data; if so, it controls the positioning module and the inertial measurement unit to synchronously perform data acquisition operations according to a preset cycle; wherein, the attitude data collected by the inertial measurement unit is used to calculate the relative heading angle.

[0208] Furthermore, the motion control module is also used to release the steering wheel lock state of the lawnmower after calculating the initial angle of the steering wheel based on the turning radius of all the first type of position points and the reference distance, so as to perform motion control on the lawnmower based on the initial angle of the steering wheel; it is also used to control the steering wheel to rotate to a preset angle and perform a power-off operation if a power-off command is received.

[0209] Since the embodiments of the system part correspond to the embodiments of the method part, please refer to the description of the embodiments of the method part for the embodiments of the system part, and they will not be repeated here.

[0210] This application also provides a storage medium on which a computer program is stored, which, when executed, can perform the steps provided in the above embodiments. The storage medium may include various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0211] This application also provides an electronic device that may include a memory and a processor. The memory stores a computer program, and when the processor calls the computer program in the memory, it can implement the steps provided in the above embodiments. Of course, the electronic device may also include various network interfaces, power supplies, and other components.

[0212] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

[0213] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A method for determining the initial angle of a steering wheel, characterized in that, include: After the lawnmower is started, it is controlled to move at a constant speed while the steering wheel is locked; wherein, the steering wheel is locked means that the angle of the steering wheel remains unchanged. The actual trajectory of the lawnmower during uniform motion is determined based on the positioning data. N position points are selected from the actual trajectory with a fixed step size, and the relative heading angle of the lawnmower at each of the position points is determined. The positioning data is collected by a positioning module installed on the lawnmower, and the actual trajectory is used to describe the positional changes of the installation point of the positioning module. Multiple point pairs satisfying distance constraints are selected from all the said location points; wherein each point pair includes one first-type location point and one second-type location point; the distance constraint is: the distance between the first-type location point and the second-type location point is greater than a preset distance, and the preset distance is greater than the fixed step size; in the same point pair, the time point when the lawnmower passes the first-type location point is earlier than the time point when the lawnmower passes the second-type location point; The horizontal distance between the mounting point of the positioning module and the center of the front wheel axle is set as the reference distance; Calculate the turning radius corresponding to each of the first type of position points based on the relative heading angle of the first type of position points, the relative heading angle of the second type of position points, the position coordinates of the first type of position points, and the position coordinates of the second type of position points; The initial angle of the steering wheel is calculated based on the turning radius of all the first type of position points and the reference distance.

2. The method for determining the initial angle of a steering wheel according to claim 1, characterized in that, Based on the relative heading angle of the first type of position point, the relative heading angle of the second type of position point, the position coordinates of the first type of position point, and the position coordinates of the second type of position point, calculate the turning radius corresponding to each first type of position point, including: Substituting the relative heading angle of the first type of position point, the relative heading angle of the second type of position point, the position coordinates of the first type of position point, and the position coordinates of the second type of position point into the radius calculation formula, we obtain the turning radius corresponding to each first type of position point. ; The formula for calculating the radius is as follows: , The X-axis coordinates of the first type of location points are represented. This represents the Y-axis coordinate of the first type of location point. This represents the X-axis coordinate of the second type of location point. This represents the Y-axis coordinate of the second type of location point. This represents the relative heading angle of the first type of location point. This represents the relative heading angle of a second type of location point.

3. The method for determining the initial angle of a steering wheel according to claim 1, characterized in that, The initial angle of the steering wheel is calculated based on the turning radius of all the first type of position points and the reference distance, including: Calculate the steering angle of the first type of position point based on the turning radius and the reference distance; The average value of the steering angles of all the first type of position points is set as the initial angle of the steering wheel.

4. The method for determining the initial angle of the steering wheel according to claim 3, characterized in that, Calculating the steering angle of the first type of position point based on the turning radius and the reference distance includes: The turning radius Substituting the reference distance L into the angle calculation formula, the turning angle of the first type of position point is obtained. ; The formula for calculating the angle is as follows: .

5. The method for determining the initial angle of a steering wheel according to claim 1, characterized in that, Before determining the actual trajectory of the lawnmower during its uniform motion based on positioning data, the process also includes: A navigation coordinate system is established with the positioning base station corresponding to the positioning module as the origin; The rear wheel axle center is determined based on the structural parameters of the lawnmower, and a carrier coordinate system is established with the rear wheel axle center as the origin. Determine the coordinate transformation matrix between the navigation coordinate system and the vehicle coordinate system; Determine the relative position of the antenna installation position of the positioning module with respect to the center of the rear wheel axle, and calculate the positioning correction parameters based on the relative position and the coordinate system transformation matrix; The positioning data collected by the positioning module is corrected using the positioning correction parameters.

6. The method for determining the initial angle of a steering wheel according to claim 1, characterized in that, Before determining the actual trajectory of the lawnmower during its uniform motion based on positioning data, the process also includes: The system determines whether the lawnmower is moving at a constant speed based on the data detected by the wheel speed meter. If so, the positioning module and the inertial measurement unit are controlled to synchronously perform data acquisition operations according to a preset cycle; wherein, the attitude data acquired by the inertial measurement unit is used to calculate the relative heading angle.

7. The method for determining the initial angle of a steering wheel according to claim 1, characterized in that, After calculating the initial angle of the steering wheel based on the turning radii of all the first type of location points and the reference distance, the method further includes: Release the steering wheel lock of the lawnmower to enable motion control of the lawnmower based on the initial angle of the steering wheel; If a power-off command is received, the steering wheel is rotated to a preset angle to perform a power-off operation.

8. A steering wheel initial angle determination system, characterized in that, include: The motion control module is used to control the lawnmower to move at a constant speed while the steering wheel is locked after the lawnmower is started; wherein, the steering wheel is locked means that the angle of the steering wheel remains unchanged. The trajectory analysis module is used to determine the actual motion trajectory of the lawnmower during uniform motion based on the positioning data, select N position points from the actual motion trajectory according to a fixed step size, and determine the relative heading angle of the lawnmower at each of the position points; wherein, the positioning data is collected by the positioning module installed on the lawnmower, and the actual motion trajectory is used to describe the positional changes of the installation point of the positioning module; The point pair selection module is used to select multiple point pairs that satisfy distance constraints from all the location points; wherein each point pair includes one first-type location point and one second-type location point; the distance constraint is that the distance between the first-type location point and the second-type location point is greater than a preset distance, and the preset distance is greater than a fixed step size; in the same point pair, the time when the lawnmower passes the first-type location point is earlier than the time when the lawnmower passes the second-type location point. The distance setting module is used to set the horizontal distance between the mounting point of the positioning module and the center of the front wheel axle as a reference distance; The radius calculation module is used to calculate the turning radius corresponding to each of the first type of position points based on the relative heading angle of the first type of position points, the relative heading angle of the second type of position points, the position coordinates of the first type of position points, and the position coordinates of the second type of position points. An angle calculation module is used to calculate the initial angle of the steering wheel based on the turning radius of all the first type of position points and the reference distance.

9. An electronic device, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program, and the processor, when calling the computer program in the memory, implements the steps of the method for determining the initial angle of the steering wheel as described in any one of claims 1 to 7.

10. A storage medium, characterized in that, The storage medium stores computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the method for determining the initial angle of the steering wheel as described in any one of claims 1 to 7.

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