WO2024045373A1

WO2024045373A1 - Steering wheel rotation angle calculation method, apparatus and device, and readable storage medium

Info

Publication number: WO2024045373A1
Application number: PCT/CN2022/134510
Authority: WO
Inventors: 左志远; 黄梓峻; 陈宏润
Original assignee: 广州文远知行科技有限公司
Priority date: 2022-09-01
Filing date: 2022-11-25
Publication date: 2024-03-07
Also published as: CN115402336A

Abstract

A steering wheel rotation angle calculation method, comprising: when transverse movement occurs in the traveling direction of a target vehicle, determining a first steering wheel rotation angle of the target vehicle at a control terminal for the target vehicle; and after the first steering wheel rotation angle is determined, performing compensation calculation on the first steering wheel rotation angle on the basis of a preset reverse stretch rate, so as to obtain a target steering wheel rotation angle of the target vehicle. The method may facilitate a reduction in an error between a steering wheel rotation angle of a vehicle during transverse movement and a steering wheel rotation angle required by a desired traveling trajectory path autonomously planned by the tracked vehicle, such that the deviation between the current traveling trajectory path of the vehicle and the desired traveling trajectory path autonomously planned by the vehicle can be effectively reduced, and the accuracy of vehicle traveling is improved. Further provided are a steering wheel rotation angle calculation apparatus, a steering wheel rotation angle calculation device and a readable storage medium.

Description

Steering wheel angle calculation method, device, equipment and readable storage medium

This application claims the priority of the Chinese patent application submitted to the China Patent Office on September 1, 2022, with the application number 202211064593.9 and the invention title "Direction rotation angle calculation method, device, equipment and readable storage medium", and its entire content incorporated herein by reference.

Technical field

This application relates to the field of autonomous driving technology, and in particular to a directional wheel angle calculation method, device, equipment and readable storage medium.

Background technique

With the development of science and technology, autonomous driving technology has also gradually developed. In actual application, the vehicle performing the autonomous driving task can plan a desired driving trajectory on its own based on the surrounding information of the current driving environment. At the same time, it can adjust the steering wheel in time based on the current trajectory of the vehicle performing the autonomous driving task. corner, so that the current driving trajectory of the vehicle currently performing the autonomous driving task will not deviate too much from the expected driving trajectory planned by the vehicle itself, thereby ensuring that the vehicle performing the autonomous driving task can drive according to the desired driving path planned by itself. Track route travel. Therefore, when the current driving trajectory of the vehicle performing the autonomous driving task deviates from the expected driving trajectory planned by the vehicle itself, the vehicle's steering wheel can correct the vehicle's driving direction by adjusting the steering wheel's angle.

When the angle between the vehicle and the reference line on which the vehicle travels increases, the error in calculating the vehicle's directional turning angle using the linear model will also increase. Therefore, the directional turning angle calculated using the linear model does not match the expectation of the tracking vehicle's self-planning. The steering wheel angle error required for the driving trajectory becomes larger.

Contents of the invention

This application aims to solve at least one of the above technical deficiencies. In view of this, this application provides a directional wheel angle calculation method, device, equipment and readable storage medium to solve the problem of determining the vehicle directional wheel in the prior art. Technical defect of large corner error.

A method for calculating steering wheel angle, including:

When the target vehicle's traveling direction moves laterally, at the control terminal of the target vehicle, determine the first direction wheel turning angle of the target vehicle;

Based on the preset reverse stretching rate, the first direction wheel turning angle is compensated and calculated to obtain the target direction wheel turning angle of the target vehicle.

Preferably, the step of calculating the reverse stretch rate includes:

Decompose the driving speed of the target vehicle at the center of gravity projection point to obtain the nonlinear speed component and linear speed component at the center of gravity respectively;

The nonlinear velocity component at the center of gravity is simulated as a circular trajectory of the center of gravity, and the linear velocity component is simulated as an elliptical trajectory of the center of gravity, and the forward stretching rate of the circular trajectory of the center of gravity transformed into an elliptical trajectory of the center of gravity is solved;

Based on the forward stretching ratio, the reverse stretching ratio is obtained.

Preferably, the step of performing compensation calculation on the first directional wheel angle to obtain the target directional wheel angle of the target vehicle includes:

Decompose the driving speed of the target vehicle at the non-directional wheels to obtain the non-directional wheel linear speed components;

Using the reverse stretch rate to correct the linear trajectory represented by the linear velocity component of the non-directional wheel, construct a conversion relationship between the first direction rotation angle, the reverse stretch rate and the target direction rotation angle;

According to the conversion relationship, the target direction wheel angle of the target vehicle is calculated.

Preferably, the center of gravity projection point is the projection point of the center of gravity of the target vehicle on the road on which it is traveling;

The linear velocity component at the center of gravity includes the first velocity of the target vehicle's traveling speed along the road tangent direction and the second velocity along the road normal direction;

The nonlinear velocity component at the center of gravity includes a third velocity of the target vehicle's traveling speed along the tangential direction of the road and a fourth velocity along the normal direction of the road.

Preferably, the nonlinear velocity component at the center of gravity is simulated as a circular trajectory of the center of gravity, and the linear velocity component is simulated as an elliptical trajectory of the center of gravity, and the forward stretching of the circular trajectory of the center of gravity into an elliptical trajectory of the center of gravity is solved. rates, including:

Comparing the first speed and the third speed, a first stretching ratio is obtained;

Comparing the second speed and the fourth speed, a second stretching ratio is obtained;

Substitute the first stretch ratio and the second stretch ratio into the elliptical curvature formula to obtain the forward stretch ratio.

Preferably, the step of determining the first direction wheel turning angle of the target vehicle includes:

Obtain the real-time speed of the target vehicle;

According to the real-time speed, use a preset linear model to determine the real-time rotation radius of the non-directional wheels of the target vehicle;

The first directional wheel rotation angle is calculated by using the real-time rotation radius of the non-directional wheel and obtaining the distance from the midpoint of the directional wheel axis of the target vehicle to the midpoint of the non-directional wheel axis.

Preferably, determining whether the target vehicle has moved laterally in its traveling direction includes:

Determine the first angle between the vehicle body orientation of the target vehicle and the road direction;

Determine whether the first included angle is greater than a preset first threshold;

If the first included angle is greater than the first threshold, it is determined that the traveling direction of the target vehicle has moved laterally.

Preferably, the value range of the preset first threshold is [0°, 20°].

A steering wheel angle calculation device, including:

A first calculation unit configured to determine, at the control terminal of the target vehicle, the first directional wheel turning angle of the target vehicle when the target vehicle's traveling direction moves laterally;

The second calculation unit is configured to perform compensation calculations on the first direction wheel turning angle based on the preset reverse stretching rate to obtain the target direction wheel turning angle of the target vehicle.

A steering wheel angle calculation device, including: one or more processors, and a memory;

Computer-readable instructions are stored in the memory. When the computer-readable instructions are executed by the one or more processors, the steps of the directional rotation angle calculation method as described in any one of the foregoing introductions are implemented.

A readable storage medium in which computer-readable instructions are stored. When executed by one or more processors, the computer-readable instructions cause one or more processors to implement any of the above introductions. One step of the directional wheel angle calculation method.

It can be seen from the technical solution introduced above that when the target vehicle moves laterally in the traveling direction, the directional wheel angle calculation method provided by the embodiment of the present application can determine the first direction of the target vehicle at the control terminal of the target vehicle. Directional wheel turning angle; after determining the first directional wheeling angle, the first directional wheeling angle can be compensated and calculated based on the preset reverse stretch rate to obtain the target directional wheeling angle of the target vehicle. The directional wheel angle calculation method provided by the embodiment of the present application can help reduce the error between the directional wheel angle of the vehicle's lateral movement and the directional wheel angle required to track the desired driving trajectory planned by the vehicle itself, and can effectively reduce the current driving speed of the vehicle. The deviation between the trajectory route and the expected driving trajectory route planned by the vehicle itself, and improve the accuracy of vehicle driving.

Description of drawings

In order to explain the embodiments of the present application or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting any creative effort.

Figure 1 is a schematic diagram comparing three driving effects of a vehicle performing driving tasks provided by the embodiment of the present application.

Figure 2 is a flow chart of a method for calculating a direction rotation angle provided by an embodiment of the present application;

Figure 3 is a schematic diagram of the effect of using the linearization method to analyze the real-time motion trajectory of the vehicle provided by the embodiment of the present application;

Figure 4 is a schematic diagram of the effect of using the nonlinear method to analyze the real-time motion trajectory of the vehicle provided by the embodiment of the present application;

Figure 5 is a schematic structural diagram of a directional wheel angle calculation device according to an example of an embodiment of the present application;

Figure 6 is a hardware structure block diagram of a directional rotation angle calculation device disclosed in the embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

In practical applications, the real-time driving trajectory of the vehicle performing the driving task is generally analyzed nonlinearly based on the kinematic equations to obtain the vehicle's forward speed along the body, and based on this, the vehicle's lateral motion is calculated. However, the nonlinear analysis method requires a large amount of calculation and cannot quickly obtain the steering wheel angle required for the vehicle to move laterally. In practical applications, when the vehicle is driving, since the calculation of the directional wheel rotation angle of the vehicle for lateral movement needs to be timely, it is necessary to quickly calculate the directional wheel rotation angle required for the vehicle to perform lateral movement while performing the driving task. Therefore, someone Consider approximating the nonlinear analysis and treating the steering wheel rotation trajectory of the vehicle's real-time motion as a circle. Based on this, perform a kinematic linearization analysis of the vehicle's real-time motion to quickly obtain the vehicle's real-time motion. The directional rotation angle required for lateral movement. However, the directional wheel turning angle of a vehicle running laterally obtained through linear analysis often has a large error, which can easily cause the vehicle to deviate from the predetermined driving trajectory.

For example, as shown in Figure 1 below, Figure 1 illustrates a comparison diagram of three driving effects of a vehicle performing a driving task.

In Figure 1, the rectangular box represents the obstacles that the vehicle performing the driving task needs to avoid during driving, and the dotted curve represents the desired trajectory route of the vehicle performing the driving task.

As shown in the rendering (b), if the directional turning angle required for the vehicle to perform lateral movement obtained by linear analysis is directly used as the directional turning angle for the vehicle performing the driving task to adjust the driving direction, by following the direction of the vehicle performing the driving task It can be found from the driving trajectory that as the vehicle travels, the vehicle gradually deviates from the vehicle's expected driving trajectory.

As shown in the schematic diagram of (c), if a steering angle compensation angle is added to the directional wheel rotation angle required for the vehicle to perform lateral movement obtained according to the linear analysis, then the driving direction is adjusted as a vehicle performing the driving task. As for the wheel turning angle, by following the driving trajectory of the vehicle performing the driving task, it can be found that as the vehicle travels, the vehicle can drive according to the vehicle's expected driving trajectory.

It can be seen from this that it is necessary to perform compensation calculations on the vehicle's directional wheel angle obtained by linear analysis.

In view of the fact that most of the current directional wheel angle calculation schemes are difficult to adapt to complex and changeable business data, the applicant has studied a directional wheel angle calculation scheme. This calculation method can be determined by the control terminal of the target vehicle. The first directional wheel angle of the target vehicle is compensated and calculated to obtain the directional wheel angle of the vehicle's lateral movement, which is helpful to ensure that the vehicle can travel according to the preset driving trajectory.

This application can be applied to any device that can realize the calculation of the steering angle. Optionally, the device that can realize the calculation of the steering angle can be a vehicle-mounted computing terminal, or a tablet computer, a mobile phone, etc. with sufficient computing power. Terminal with data processing capabilities.

The following describes the process of the direction rotation angle calculation method given in the embodiment of the present application with reference to Figure 2. The process may include the following steps:

Step S101: When the traveling direction of the target vehicle moves laterally, the control terminal of the target vehicle determines the first directional wheel turning angle of the target vehicle.

Specifically, during the driving process of the vehicle, when the traveling direction of the target vehicle moves laterally, the steering wheel angles required to adjust different directions are different. Therefore, in the method provided by the embodiment of the present application, when the target vehicle The control terminal determines the first direction wheel turning angle of the target vehicle. So that the target direction rotation angle can be determined according to the first direction rotation angle.

For example, in order to ensure calculation timeliness, the method provided by the embodiment of the present application can use linear analysis to obtain the directional wheel angle required when the vehicle performing the driving task makes lateral movement.

For example, a preset linear model can be used to calculate the steering angle required when a vehicle performing a driving task makes lateral movement.

Step S102: Compensate the first directional wheel angle based on the preset reverse stretch rate to obtain the target directional wheel angle of the target vehicle.

Specifically, as can be seen from the above introduction, the method provided by the embodiment of the present application can use linearization analysis to obtain the directional wheel rotation angle required when the vehicle performing the driving task performs lateral movement. As can be seen from the above introduction, the method obtained through linearization analysis The steering angle of a vehicle running laterally often has a large error, which can easily cause the vehicle to deviate from the predetermined driving trajectory.

In order to reduce the error of the directional wheel angle, the directional wheel angle required for the lateral movement of the vehicle performing the driving task can be obtained by linearization analysis, and then the second directional wheel angle obtained after the angle compensation is used as The target direction wheel rotation angle required for the vehicle performing the driving task to make lateral movement.

Since the first directional wheel turning angle is calculated using a vehicle-mounted computing terminal based on a simplified calculation model, it can be seen from experiments that there is an error in the first directional wheel turning angle calculated using the vehicle-mounted computing terminal based on a simplified calculation model, and it is necessary to use a preset The reverse stretching rate performs error correction on the first direction rotation angle, so that a more accurate direction rotation angle can be obtained.

Therefore, in order to further determine the target direction wheel turning angle required when the vehicle performing the driving task makes lateral movement, after determining the first direction wheel turning angle of the target vehicle, the target vehicle can be further determined based on the preset reverse stretching rate. The first directional wheel angle is compensated and calculated so that the target directional wheel angle of the target vehicle can be obtained.

It can be seen from the technical solution introduced above that when the target vehicle moves laterally in the traveling direction, the directional wheel angle calculation method provided by the embodiment of the present application can determine the first directional wheel of the target vehicle at the control terminal of the target vehicle. Rotation angle; after determining the first direction wheel rotation angle, the first direction wheel rotation angle can be compensated and calculated based on the preset reverse stretch rate to obtain the target direction wheel rotation angle of the target vehicle. The directional wheel angle calculation method provided by the embodiment of the present application can help reduce the error between the directional wheel angle of the vehicle's lateral movement and the directional wheel angle required to track the desired driving trajectory planned by the vehicle itself, and can effectively reduce the current driving speed of the vehicle. The deviation between the trajectory route and the expected driving trajectory route planned by the vehicle itself, and improve the accuracy of vehicle driving.

As can be seen from the above introduction, the directional wheel angle calculation method provided by the embodiment of the present application can perform compensation calculations on the first directional wheel angle based on a preset reverse stretch rate to obtain the target directional wheel angle of the target vehicle. Next, with reference to Figures 3 and 4, the calculation process of the preset reverse stretch rate is introduced. This process may include the following steps:

Step S201: Decompose the traveling speed of the target vehicle at the center of gravity projection point to obtain the nonlinear speed component and linear speed component at the center of gravity.

Specifically, as can be seen from the above introduction, the method provided by the embodiment of the present application can use a linear analysis method to determine the directional turning angle of the target vehicle.

In the actual application process, the driving speed of the target vehicle can be decomposed at the projection point of the vehicle's center of gravity on the road where the vehicle is traveling, and the nonlinear speed component and linear speed component of the vehicle at the center of gravity can be obtained respectively. So that the forward stretch ratio can be solved.

in,

The center of gravity projection point is the projection point of the center of gravity of the target vehicle on the road;

The linear velocity component at the center of gravity includes a first velocity of the target vehicle's traveling speed along the road tangent direction and a second velocity along the road normal direction.

As shown in Figures 3 and 4, θ in the figure represents the steering angle of the front wheel, a and b represent the stretch ratio, and L is the wheelbase of the vehicle.

Indicates the angle between the vehicle body orientation and the road direction. Figure 3 is a schematic diagram of the effect of analyzing the real-time motion trajectory of the vehicle using the linearization method provided by the embodiment of the present application; Figure 4 is the analysis using the nonlinear method provided by the embodiment of the present application. Schematic diagram of the effect of the vehicle’s real-time movement trajectory;

Describe the first rate as: u _x ;

Then the second rate can be:

The third rate may be:

The fourth rate may be:

Step S202: The nonlinear velocity component at the center of gravity is simulated as a circular trajectory of the center of gravity, and the linear velocity component is simulated as an elliptical trajectory of the center of gravity, and the forward stretching rate of the circular trajectory of the center of gravity transformed into an elliptical trajectory of the center of gravity is solved.

Specifically, in actual application, when the vehicle is moving laterally, all points on the vehicle move around the same circle center to complete the direction adjustment.

The linearization analysis method is to regard the trajectory of all points on the vehicle around the same center of the circle as an elliptical trajectory when the target vehicle moves laterally.

In the actual driving process, when the vehicle is moving laterally, the trajectory formed by all points on the vehicle moving around the same circle center can be regarded as a circular trajectory.

In the method provided by the embodiment of the present application, the nonlinear velocity component of the target vehicle at the center of gravity can be modeled as a circular trajectory of the center of gravity, and the linear velocity component can be modeled as an elliptical trajectory of the center of gravity. After obtaining the circular trajectory of the center of gravity, After the trajectory and the gravity elliptical trajectory are determined, the forward stretch rate of the transformation of the gravity circular trajectory into the gravity elliptical trajectory can be further solved.

In order to improve calculation efficiency, a preset linear model can be used to calculate the nonlinear speed component, and a preset nonlinear model linear model can be used to calculate the linearized speed component.

Step S203: Obtain the reverse stretching rate based on the forward stretching rate.

Specifically, as can be seen from the above introduction, the method provided by the embodiment of the present application can determine the forward stretching rate of the circular trajectory of the center of gravity to the elliptical trajectory of the center of gravity. Based on the forward stretching rate, the center of gravity can be determined The reverse stretch rate for transforming an elliptical trajectory into a centroid circular trajectory. So that it can be used to calculate the target direction rotation angle.

Wherein, the numerical value of the forward stretching rate is equal to the numerical value of the reverse stretching rate.

It can be seen from the technical solution introduced above that the method provided by the embodiment of the present application can solve the center of gravity circle by simulating the nonlinear velocity component at the center of gravity into a circular trajectory of the center of gravity and the linear velocity component into an elliptical trajectory of the center of gravity. The positive stretch rate of transforming the rectangular trajectory into the centroid elliptical trajectory. The reverse stretch ratio is thus determined so that it can be used to calculate the vehicle's target directional wheel angle. The directional wheel angle calculation method provided by the embodiment of the present application can help reduce the error between the directional wheel angle of the vehicle's lateral movement and the directional wheel angle required to track the desired driving trajectory planned by the vehicle itself, and can effectively reduce the current driving speed of the vehicle. The deviation between the trajectory route and the expected driving trajectory route planned by the vehicle itself, and improve the accuracy of vehicle driving.

In actual application, the method provided by the embodiments of the present application can perform compensation calculations on the first direction wheel angle based on a preset reverse stretch rate to obtain the target direction wheel angle of the target vehicle. The following is introduced The process of performing compensation calculations on the first directional wheel angle to obtain the target directional wheel angle of the target vehicle may include the following steps:

Step S301: Decompose the traveling speed of the target vehicle at the non-directional wheels to obtain the linear velocity components of the non-directional wheels.

Specifically, as can be seen from the above introduction, the method provided by the embodiment of the present application can use a linear analysis method to decompose the speed of the target vehicle. Therefore, the traveling speed of the target vehicle can be decomposed at the non-directional wheel, From this, the non-directional wheel linear velocity component can be obtained.

Wherein, the non-directional wheel linear velocity component may be a velocity component calculated using a preset linear model.

Step S302, use the reverse stretch rate to correct the linear trajectory represented by the linear velocity component of the non-directional wheel, and construct a conversion relationship between the first direction wheel angle, the reverse stretch rate and the target direction wheel angle. Mode.

Specifically, after determining the linear velocity component of the non-directional wheel, the reverse stretching rate can be used to determine the relationship between the nonlinear velocity component and the linearized velocity component of the target vehicle at the center of gravity projection. The linear trajectory represented by the linear velocity component of the non-directional wheel is corrected, and the conversion relationship between the first direction wheel rotation angle, the reverse stretch rate and the target direction wheel rotation angle is constructed, so that the first direction wheel rotation angle can be And the directional stretch rate is used to calculate the target direction rotation angle.

Wherein, the conversion relationship between the rotation angle in the first direction, the reverse stretch rate and the rotation angle in the target direction may include the following:

in,

It can represent the preset reverse stretch rate;

θ ₁ can represent the first direction rotation angle;

θ ₂ can represent the target direction rotation angle.

Step S303: Calculate the target directional wheel turning angle of the target vehicle based on the conversion relationship.

Specifically, it can be seen from the above introduction that the above steps can determine the conversion relationship between the first direction rotation angle, the reverse stretch rate and the target direction rotation angle. Therefore, after determining the first direction rotation angle, it can be based on The conversion relational expression and the preset reverse stretching rate are used to calculate the target direction wheel rotation angle of the target vehicle.

As can be seen from the above introduction, the method provided by the embodiment of the present application can perform compensation calculation on the first direction wheel angle based on the preset reverse stretching rate to obtain the target direction wheel angle of the target vehicle. The directional wheel angle calculation method provided can help reduce the error between the directional wheel angle of the vehicle's lateral movement and the directional wheel angle required to track the desired driving trajectory planned by the vehicle itself, and can effectively reduce the relationship between the vehicle's current driving trajectory and the vehicle's desired driving trajectory. Deviations between self-planned desired driving trajectory routes and improve vehicle driving accuracy.

As can be seen from the above introduction, the method provided by the embodiment of the present application can simulate the nonlinear velocity component at the center of gravity into a circular trajectory of the center of gravity, and the linear velocity component into an elliptical trajectory of the center of gravity, and solve the transformation of the circular trajectory of the center of gravity into The forward stretching rate of the center of gravity ellipse trajectory is introduced next. The process can include the following steps:

Step S401: Compare the first speed and the third speed to obtain a first stretching ratio.

Specifically, as can be seen from the above introduction, the method provided by the embodiment of the present application can decompose the traveling speed of the target vehicle at the center, thereby obtaining the first rate and the third rate, thus The first speed and the third speed can be compared to obtain a first stretch ratio, wherein the first stretch ratio can represent the trajectory stretch ratio of the target vehicle's traveling speed along the road tangent direction, that is, the The stretch ratio of the circular trajectory to the elliptical trajectory along the tangent direction of the road.

The calculation formula of the first stretch ratio may include the following:

in,

a can represent the first stretching ratio;

u _x may represent the first rate;

The third rate may be represented;

It can represent the angle between the body orientation of the target vehicle performing the driving task and the road direction.

Step S402: Compare the second speed and the fourth speed to obtain a second stretching ratio.

Specifically, as can be seen from the above introduction, the method provided by the embodiment of the present application can decompose the traveling speed of the target vehicle at the center, thereby obtaining the second rate and the fourth rate, thus The second speed and the fourth speed can be compared to obtain a second stretching ratio, wherein the second stretching ratio can represent the trajectory stretching ratio of the target vehicle's traveling speed along the normal direction of the road, that is, the The stretching ratio of the circular trajectory and the elliptical trajectory along the normal direction of the road.

The calculation formula of the second stretch ratio may include the following:

in,

b can represent the second stretching ratio;

The second rate may be represented;

can represent the fourth rate;

Step S403: Substitute the first stretching ratio and the second stretching ratio into the elliptical curvature formula to obtain the forward stretching ratio.

Specifically, it can be known from the technical solution introduced above that the method provided by the embodiment of the present application can calculate the first stretch ratio and the second stretch ratio,

The calculation formula of the forward stretch rate may include the following:

in,

k ₁ may represent the first curvature of determining the instant motion trajectory of the target vehicle at the center of gravity using a preset linear model;

k ₂ may represent the second curvature of the immediate motion trajectory after compensating the directional wheel angle of the target vehicle at the center of gravity;

a may represent the first stretch ratio of the speed of the target vehicle at the target point along the tangential direction;

b may represent the second stretch ratio of the speed of the target vehicle at the target point along the normal direction;

t can represent the parameters in the parameter expression of the ellipse, and its value range is 0-2π. Any value of t determines a point on the elliptical trajectory. When stretching from a circular trajectory to an elliptical trajectory, the parameters of the circular trajectory and the parameters of the elliptical trajectory have a corresponding relationship. Correspondingly, in this embodiment, according to the body coordinate system frene and the rectangular coordinate system with the center of the elliptical trajectory as the origin middle

The relationship with t can be known:

when

It can be seen from the technical solution introduced above that the method provided by the embodiment of the present application can simulate the nonlinear velocity component at the center of gravity into a circular trajectory of the center of gravity, and the linear velocity component into an elliptical trajectory of the center of gravity, and solve the circular trajectory of the center of gravity The trajectory is transformed to the forward stretch rate of the centroid ellipse trajectory so that the reverse stretch rate can be solved based on the forward stretch rate. So that the first directional wheel angle can be compensated and calculated based on the reverse stretch rate to obtain the target directional wheel angle of the target vehicle. The directional wheel angle calculation method provided by the embodiment of the present application can help reduce The error between the directional rotation angle of the vehicle's lateral movement and the directional rotation angle required to track the vehicle's self-planned desired driving trajectory can effectively reduce the deviation between the vehicle's current driving trajectory and the vehicle's self-planned desired driving trajectory. and improve vehicle driving accuracy.

As can be seen from the above introduction, the embodiment of the present application can determine the first directional wheel rotation angle of the target vehicle. Next, the process will be introduced. The process may include the following steps:

Step S501: Obtain the real-time speed of the target vehicle.

Specifically, in actual application, when the vehicle moves laterally, the vehicle's directional turning angle is related to the vehicle's real-time speed. Therefore, before determining the first directional turning angle of the target vehicle, the target can be obtained first The real-time speed of the vehicle, so that the first direction wheel turning angle can be calculated using the real-time speed of the target vehicle.

Step S502: Use a preset linear model to determine the real-time rotation radius of the non-directional wheels of the target vehicle according to the real-time speed.

Specifically, as can be seen from the above introduction, the method provided by the embodiment of the present application can determine the real-time speed of the target vehicle. After determining the real-time speed, the real-time speed can be used to calculate the real-time speed of the non-directional wheels of the target vehicle. turning radius.

in,

To calculate the real-time rotation radius of the non-directional wheel, you can refer to the following calculation formula:

in,

R can represent the real-time rotation radius of the non-directional wheels of the target vehicle;

V can represent the real-time speed of the target vehicle;

W may represent the angular velocity of the target vehicle.

Step S503: Use the real-time rotation radius of the non-directional wheel and obtain the distance from the midpoint of the directional wheel axis of the target vehicle to the midpoint of the non-directional wheel axis, and calculate the first directional wheel rotation angle.

Specifically, as can be seen from the above introduction, the method provided by the embodiment of the present application can determine the real-time rotation radius of the non-directional wheel. The directional wheel rotation angle of the target vehicle is related to the real-time rotation radius of the non-directional wheel of the target vehicle. Therefore, After determining the real-time rotation radius of the non-directional wheel, the distance from the midpoint of the directional wheel axis to the midpoint of the non-directional wheel axis of the target vehicle can be further obtained. Then, a preset linear model can be used to calculate the first directional wheel angle, so that it can be used to calculate the target directional wheel angle of the target vehicle.

Wherein, the distance from the midpoint of the directional wheel axis of the target vehicle to the midpoint of the non-directional wheel axis can be recorded as the wheelbase of the target vehicle, and the symbol L can be used to represent the wheelbase of the target vehicle.

In addition, any other calculation method can also be used to obtain the first direction wheel angle.

For example, the first directional wheel turning angle may be calculated using the angle between the body of the target vehicle and the road on which the target vehicle is currently traveling.

The instantaneous turning radius of the target vehicle can also be calculated according to a preset nonlinear model, and the first direction wheel turning angle can further be calculated.

For example, the calculation formula of the first direction rotation angle can be as follows:

in,

θ can represent the first direction rotation angle;

L can represent the wheelbase of the target vehicle;

R may represent the real-time rotation radius of the non-directional wheels of the target vehicle.

It can be seen from the technical solution introduced above that the method provided by the embodiment of the present application can determine the initial directional wheel turning angle of the vehicle through the real-time turning radius of the non-directional wheel of the vehicle or the instantaneous turning radius of the vehicle or the real-time speed of the vehicle, so that it can be based on The vehicle's initial directional turning angle is used to perform compensation calculations to determine the vehicle's target directional turning angle. The directional wheel angle calculation method provided by the embodiment of the present application can help reduce the error between the directional wheel angle of the vehicle's lateral movement and the directional wheel angle required to track the desired driving trajectory planned by the vehicle itself, and can effectively reduce the current driving speed of the vehicle. The deviation between the trajectory route and the expected driving trajectory route planned by the vehicle itself, and improve the accuracy of vehicle driving.

In actual application, when the angle of lateral movement of the target vehicle's traveling direction is not large, it is possible that the vehicle slightly adjusts its current traveling direction, which is not considered to be a lateral movement. At the control terminal of the target vehicle, the determined error of the first directional wheel rotation angle of the target vehicle is not large, and there is no need to make lateral adjustments to the current driving direction. The target vehicle can directly turn the first directional wheel according to the direction of the target vehicle. Turn the corner to adjust the direction of lateral movement without deviating from the desired driving trajectory. When the angle of lateral movement of the target vehicle in the traveling direction exceeds a certain angle, the error in the determined first direction wheel turning angle of the target vehicle at the control terminal of the target vehicle will be too large. At this time, the vehicle may It is necessary to change the current driving direction and switch to the lateral movement direction. Next, we will introduce the process of how to determine whether the target vehicle's driving direction has moved laterally. This process may include the following steps:

Step S601: Determine the first angle between the vehicle body orientation of the target vehicle and the road direction.

Specifically, when the vehicle's form shifts laterally. The error in the preset steering angle is related to the angle between the vehicle body orientation and the road direction.

Therefore, if you need to know whether the vehicle needs to move laterally. The first angle between the vehicle body orientation of the target vehicle and the road direction may be determined first. So that it can be determined whether the vehicle needs to change the current driving direction and make lateral movement by analyzing the size of the first included angle.

Step S602: Determine whether the first included angle is greater than a preset first threshold.

Specifically, as can be seen from the above introduction, the size of the first included angle determines the size of the error of the first direction wheel rotation angle. Therefore, after determining the first included angle, it can be determined whether the first included angle is greater than the preset first threshold.

By judging the relationship between the size of the first included angle and the preset first threshold, it is determined whether the vehicle needs to adjust the current traveling direction and move laterally.

Wherein, the value range of the preset first threshold may be set to [0°, 20°].

Among them, it can be seen from experiments that when the preset first threshold value is 15°, the determined error of the first direction wheel rotation angle of the target vehicle will gradually be displayed on the control terminal of the target vehicle. This Indicates that the vehicle is about to move laterally.

Step S603: It is determined that the traveling direction of the target vehicle has moved laterally.

Specifically, as can be seen from the above introduction, the method provided by the embodiment of the present application can determine the relationship between the first included angle and the preset first threshold. If the first included angle is greater than the preset first threshold, The first threshold value means that at the control terminal of the target vehicle, the error in the determined first direction wheel turning angle of the target vehicle will be too large, and it is necessary to perform compensation calculations on the determined first direction wheel turning angle, and at the same time It also shows that the target vehicle's traveling direction has moved laterally.

It can be seen from the technical solution introduced above that the method provided by the embodiment of the present application determines whether the vehicle has moved laterally by analyzing the relationship between the first included angle and the preset first threshold. So that it can be determined whether it is necessary to calculate the steering wheel angle of the vehicle.

The directional wheel angle calculation device provided by the embodiment of the present application is described below. The directional wheel angle calculation device described below and the directional wheel angle calculation method described above can be mutually referenced.

Referring to Figure 5, Figure 5 is a schematic structural diagram of a directional wheel angle calculation device disclosed in an embodiment of the present application.

As shown in Figure 5, the direction rotation angle calculation device may include:

The first calculation unit 101 is configured to determine the first direction wheel turning angle of the target vehicle at the control terminal of the target vehicle when the traveling direction of the target vehicle moves laterally;

The second calculation unit 102 is configured to perform compensation calculations on the first directional wheel angle based on a preset reverse stretch rate to obtain the target directional wheel angle of the target vehicle.

It can be seen from the technical solution introduced above that when the target vehicle moves laterally in the traveling direction, the directional wheel angle calculation device provided by the embodiment of the present application can use the first calculation unit 101 to determine the target vehicle's control terminal. The first direction wheel turning angle of the target vehicle; after determining the first direction wheel turning angle, the second calculation unit 102 can be used to perform compensation calculations for the first direction wheel turning angle based on the preset reverse stretch rate, Obtain the target direction wheel angle of the target vehicle. The directional wheel angle calculation device provided by the embodiment of the present application can help reduce the error between the directional wheel angle of the vehicle's lateral movement and the directional wheel angle required to track the desired driving trajectory planned by the vehicle itself, and can effectively reduce the current driving speed of the vehicle. The deviation between the trajectory route and the expected driving trajectory route planned by the vehicle itself, and improve the accuracy of vehicle driving.

Further optionally, the step of calculating the reverse stretch rate may include:

According to the forward stretching rate, the reverse stretching rate is obtained;

Wherein, the center of gravity projection point is the projection point of the center of gravity of the target vehicle on the road;

Further optionally, the second computing unit 102 may include:

A speed component acquisition unit, used to decompose the traveling speed of the target vehicle at the non-directional wheels to obtain the non-directional wheel linear speed components;

A conversion relationship acquisition unit configured to use the reverse stretch rate to correct the linear trajectory represented by the linear velocity component of the non-directional wheel, and construct the first directional wheel rotation angle, the reverse stretch rate and the target directional wheel The conversion relationship of the corner;

A target direction wheel angle calculation unit is used to calculate the target direction wheel angle of the target vehicle based on the conversion relationship.

Further optionally, the nonlinear velocity component at the center of gravity is simulated as a circular trajectory of the center of gravity, and the linear velocity component is simulated as an elliptical trajectory of the center of gravity, and the forward direction of the transformation of the circular trajectory of the center of gravity into the elliptical trajectory of the center of gravity is solved. The execution process of stretch rate may include:

Further optionally, the execution process of determining the first direction wheel turning angle of the target vehicle may include:

Obtain the real-time speed of the target vehicle;

Further optionally, the device may also include:

A judgment unit used to judge whether the target vehicle moves laterally in the traveling direction;

Wherein, the judgment unit may include:

A first angle determination unit configured to determine the first angle between the vehicle body orientation of the target vehicle and the road direction;

A judgment subunit, used to judge whether the first included angle is greater than a preset first threshold;

A directional movement determination unit is configured to determine that the traveling direction of the target vehicle has moved laterally when the execution result of the determination subunit is that the first included angle is greater than the first threshold.

Further optionally, the value range of the preset first threshold may be [0°, 20°].

For the specific processing flow of each unit included in the above-mentioned directional rotation angle calculation device, please refer to the relevant introduction of the directional rotation angle calculation method mentioned above, and will not be repeated here.

The directional wheel angle calculation device provided by the embodiment of the present application can be applied to directional wheel angle calculation equipment, such as terminals: vehicle-mounted computing terminals, mobile phones, computers, etc. Optionally, Figure 6 shows a hardware structure block diagram of the steering angle calculation device. Referring to Figure 6, the hardware structure of the steering angle calculation device may include: at least one processor 1, at least one communication interface 2, and at least one memory 3 and at least one communication bus 4.

In the embodiment of the present application, the number of the processor 1, the communication interface 2, the memory 3, and the communication bus 4 is at least one, and the processor 1, the communication interface 2, and the memory 3 complete communication with each other through the communication bus 4.

The processor 1 may be a central processing unit CPU, or an application specific integrated circuit ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement embodiments of the present application, etc.;

Memory 3 may include high-speed RAM memory, and may also include non-volatile memory (non-volatile memory), such as at least one disk memory;

The memory stores a program, and the processor can call the program stored in the memory. The program is used to implement each processing flow in the aforementioned terminal direction rotation angle calculation scheme.

Embodiments of the present application also provide a readable storage medium that can store a program suitable for execution by a processor. The program is used to implement each processing flow of the aforementioned terminal in the direction rotation angle calculation scheme.

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

Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on its differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other.

The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be practiced in other embodiments without departing from the spirit or scope of the application. The various embodiments can be combined with each other. Therefore, the present application is not to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

A method for calculating steering wheel angle, which is characterized by including:

When the target vehicle's traveling direction moves laterally, at the control terminal of the target vehicle, determine the first direction wheel turning angle of the target vehicle;

Based on the preset reverse stretching rate, the first direction wheel turning angle is compensated and calculated to obtain the target direction wheel turning angle of the target vehicle.
The method according to claim 1, characterized in that the step of calculating the reverse stretch rate includes:

Decompose the driving speed of the target vehicle at the center of gravity projection point to obtain the nonlinear speed component and linear speed component at the center of gravity respectively;

The nonlinear velocity component at the center of gravity is simulated as a circular trajectory of the center of gravity, and the linear velocity component is simulated as an elliptical trajectory of the center of gravity, and the forward stretching rate of the circular trajectory of the center of gravity transformed into an elliptical trajectory of the center of gravity is solved;

Based on the forward stretching ratio, the reverse stretching ratio is obtained.
The method according to claim 2, characterized in that the step of performing compensation calculation on the first directional wheel angle to obtain the target directional wheel angle of the target vehicle includes:

Decompose the driving speed of the target vehicle at the non-directional wheels to obtain the non-directional wheel linear speed components;

Using the reverse stretch rate to correct the linear trajectory represented by the linear velocity component of the non-directional wheel, construct a conversion relationship between the first direction rotation angle, the reverse stretch rate and the target direction rotation angle;

According to the conversion relationship, the target direction wheel angle of the target vehicle is calculated.
The method according to claim 2, characterized in that:

The center of gravity projection point is the projection point of the center of gravity of the target vehicle on the road;

The linear velocity component at the center of gravity includes the first velocity of the target vehicle's traveling speed along the road tangent direction and the second velocity along the road normal direction;

The nonlinear velocity component at the center of gravity includes a third velocity of the target vehicle's traveling speed along the tangential direction of the road and a fourth velocity along the normal direction of the road.
The method according to claim 4, characterized in that the nonlinear velocity component at the center of gravity is simulated as a circular trajectory of the center of gravity, and the linear velocity component is simulated as an elliptical trajectory of the center of gravity, and the circular trajectory of the center of gravity is solved. The forward stretch rate transformed to the centroid ellipse trajectory includes:

Comparing the first speed and the third speed, a first stretching ratio is obtained;

Comparing the second speed and the fourth speed, a second stretching ratio is obtained;

Substitute the first stretch ratio and the second stretch ratio into the elliptical curvature formula to obtain the forward stretch ratio.
The method according to any one of claims 1-5, characterized in that the step of determining the first direction wheel turning angle of the target vehicle includes:

Obtain the real-time speed of the target vehicle;

According to the real-time speed, use a preset linear model to determine the real-time rotation radius of the non-directional wheels of the target vehicle;

The first directional wheel rotation angle is calculated by using the real-time rotation radius of the non-directional wheel and obtaining the distance from the midpoint of the directional wheel axis of the target vehicle to the midpoint of the non-directional wheel axis.
The method according to any one of claims 1-5, characterized in that determining whether the traveling direction of the target vehicle has moved laterally includes:

Determine the first angle between the vehicle body orientation of the target vehicle and the road direction;

Determine whether the first included angle is greater than a preset first threshold;

If the first included angle is greater than the first threshold, it is determined that the traveling direction of the target vehicle has moved laterally.
The method according to any one of claims 7, characterized in that the value range of the preset first threshold is [0°, 20°].
A steering wheel angle calculation device, which is characterized in that it includes:

A first calculation unit configured to determine, at the control terminal of the target vehicle, the first directional wheel turning angle of the target vehicle when the target vehicle's traveling direction moves laterally;

The second calculation unit is configured to perform compensation calculations on the first direction wheel turning angle based on the preset reverse stretching rate to obtain the target direction wheel turning angle of the target vehicle.
A steering wheel angle calculation device, characterized in that it includes: one or more processors and a memory;

Computer readable instructions are stored in the memory, and when the computer readable instructions are executed by the one or more processors, the steps of the steering angle calculation method according to any one of claims 1 to 8 are implemented.
A readable storage medium, characterized in that: computer-readable instructions are stored in the readable storage medium, and when the computer-readable instructions are executed by one or more processors, the one or more processors implement the following: The steps of the directional wheel angle calculation method according to any one of claims 1 to 8.