Slip Angle Estimation Method for Autonomous Driving

Abstract

The present invention provides a slip angle estimation method for autonomous driving, comprising: estimating the slip angle when a vehicle enters autonomous driving and its speed exceeds a threshold; obtaining the vehicle's speed, turning radius, and vehicle parameters; calculating the slip angle in real time based on the speed, turning radius, and vehicle parameters; performing a rationality check on the slip angle based on the slip angle and the vehicle's current state; performing lateral control compensation based on the slip angle if the check passes; and not performing lateral control compensation if the check fails. The present invention estimates the slip angle in real time while driving, then performs a rationality check on the estimated real-time slip angle, and performs real-time compensation on slip angles that pass the check, making dynamic control for autonomous driving more precise and safe.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle automatic driving control, and in particular to a slip angle estimation method applied to automatic driving. Background Art

[0002] When the vehicle is driving, when the steering wheel is turned, the tire will rotate sideways, causing the tire to undergo elastic deformation. Since the vehicle tire is elastic, the elastic deformation of the tire will cause a difference in the angle of rotation of the tread and the wheel hub. This difference in angle is the slip angle.

[0003] When autonomous driving is in operation in a vehicle, higher control precision is required for safety and passenger comfort when the vehicle speed exceeds a certain value. This requires that slip angle errors be taken into account during vehicle dynamic control for more precise control.

[0004] Currently, the slip angle is a physical quantity that requires sensors and cannot be directly obtained. Therefore, a slip angle estimation method for autonomous driving is urgently needed to solve the above problem. Summary of the Invention

[0005] The technical problem solved by the present invention is to provide a slip angle estimation method applied to autonomous driving, which can estimate the vehicle slip angle in real time according to the vehicle operating status and compensate the verified slip angle, making the dynamic control of autonomous driving more accurate and safer.

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] A slip angle estimation method for autonomous driving comprises: estimating the slip angle when a vehicle enters autonomous driving and the vehicle speed exceeds a threshold; obtaining the vehicle speed, turning radius, and vehicle parameters; calculating the slip angle in real time based on the speed, turning radius, and vehicle parameters; performing a rationality check on the slip angle based on the slip angle value and the current state of the vehicle; performing lateral control compensation based on the slip angle if the check passes; and not performing lateral control compensation if the check fails.

[0008] In a preferred embodiment of the present invention, the step of obtaining the vehicle speed value, turning radius and vehicle parameters includes: obtaining the vehicle speed value, and performing filtering and smoothing calculation on the vehicle speed value.

[0009] In a preferred embodiment of the present invention, the above-mentioned step of obtaining the vehicle speed value, turning radius and vehicle parameters also includes: obtaining lane lines through a camera device; confirming the lane in which the vehicle is located on the road based on the lane lines, and calculating the current path curvature; and calculating the current turning radius based on the current path curvature.

[0010] In a preferred embodiment of the present invention, the above-mentioned vehicle parameters include: the distance from the center of mass to the front and rear axles, the vehicle mass and the lateral stiffness; the step of obtaining the vehicle speed value, turning radius and vehicle parameters also includes: obtaining the distance from the center of mass to the front axle, the distance from the center of mass to the rear axle, the vehicle mass and the lateral stiffness.

[0011] In a preferred embodiment of the present invention, the above-mentioned vehicle status includes: vehicle speed, road turning radius and curb weight.

[0012] In a preferred embodiment of the present invention, before the step of estimating the slip angle when the vehicle enters automatic driving and the speed of the vehicle exceeds a threshold, the step includes: obtaining status information of the vehicle, detecting whether the vehicle meets the automatic driving requirements based on the status information; and confirming that the vehicle enters automatic driving when the vehicle meets the automatic driving requirements and the automatic driving function is turned on.

[0013] In a preferred embodiment of the present invention, before the step of performing slip angle estimation when the vehicle enters automatic driving and the speed of the vehicle exceeds a threshold, the step includes: not performing slip angle estimation and compensation when the vehicle has not entered automatic driving or the speed has not exceeded the threshold.

[0014] In a preferred embodiment of the present invention, the step of performing a rationality check on the slip angle based on the slip angle value and the current state of the vehicle includes: obtaining a slip angle threshold value of the vehicle based on the current state of the vehicle; comparing the slip angle with the slip angle threshold value; if the slip angle does not exceed the slip angle threshold value, determining that the slip angle is reasonable; if the slip angle exceeds the slip angle threshold value, determining that the slip angle is unreasonable.

[0015] In a preferred embodiment of the present invention, the above method further includes: when it is detected that the vehicle enters the automatic driving mode, executing the step of estimating the slip angle when the vehicle enters the automatic driving mode and the speed of the vehicle exceeds a threshold.

[0016] A slip angle estimation system for autonomous driving comprises: a memory and a processor, wherein the memory stores a slip angle estimation program, and when the slip angle estimation program is executed by the processor, the steps of the slip angle estimation system method for autonomous driving as described in any one of the above are implemented.

[0017] The technical effects achieved by the present invention using the above technical solution are as follows: after the autonomous driving software determines that the vehicle has entered the autonomous driving function and the vehicle speed is greater than a threshold, slip angle estimation is initiated; the slip angle is calculated in real time based on the vehicle speed value, turning radius, and vehicle parameters, and the rationality of the slip angle is checked; if the slip angle passes the rationality check, lateral control compensation is performed on the slip angle; if the slip angle fails the rationality check, no slip angle compensation is performed for safety reasons.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites preferred embodiments and describes them in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flowchart of a slip angle estimation method for autonomous driving according to the present invention;

[0020] Figure 2 The figure is an overall flow chart of a slip angle estimation method applied to autonomous driving shown in the present invention. DETAILED DESCRIPTION

[0021] In order to further illustrate the technical means and effects taken by the present invention to achieve the predetermined purpose of the invention, embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the embodiments of the present invention. Through the description of specific implementation methods, the technical means and effects taken by the present invention to achieve the predetermined purpose can be more deeply and specifically understood, and the accompanying drawings are only for reference and illustration purposes, and are not used to limit the present invention.

[0022] See also Figure 1 and Figure 2 . Figure 1 This is a flowchart of a slip angle estimation method for autonomous driving according to the present invention; Figure 2 The figure is an overall flow chart of a slip angle estimation method applied to autonomous driving shown in the present invention.

[0023] like Figure 1 As shown, the slip angle estimation method applied to autonomous driving of this embodiment includes the following steps:

[0024] S11: When the vehicle enters automatic driving and the speed of the vehicle exceeds a threshold, slip angle estimation is performed.

[0025] When the vehicle is driving, when the steering wheel is turned, the tire will rotate sideways, causing the tire to undergo elastic deformation. Since the vehicle tire is elastic, the elastic deformation of the tire will cause a difference in the angle of rotation of the tread and the wheel hub. This difference in angle is the slip angle.

[0026] For example, the vehicle speed exceeds a threshold value, which can be set according to different scenarios. For example, on a narrower road section, the threshold value is lower, such as 20km / h, 25km / h, etc.; on a wide road section, the threshold value can be set to a relatively high speed, such as 30km / h, 40km / h, etc.

[0027] Optionally, before the step of performing slip angle estimation when the vehicle enters automatic driving and the speed of the vehicle exceeds a threshold, the step includes: not performing slip angle estimation and compensation when the vehicle does not enter automatic driving or the speed does not exceed the threshold.

[0028] Optionally, when the vehicle enters automatic driving and the speed of the vehicle exceeds a threshold, before performing the step of slip angle estimation, it includes: obtaining status information of the vehicle, detecting whether the vehicle meets the automatic driving requirements based on the status information; when the vehicle meets the automatic driving requirements and the automatic driving function is turned on, confirming that the vehicle enters automatic driving.

[0029] Optionally, when it is detected that the vehicle enters the automatic driving mode, the step of estimating the slip angle is performed when the vehicle enters the automatic driving mode and the speed of the vehicle exceeds a threshold.

[0030] S12: Obtain the vehicle speed, turning radius, and vehicle parameters of the vehicle.

[0031] Optionally, the step of obtaining the vehicle speed value, turning radius and vehicle parameters of the vehicle includes: obtaining the vehicle speed value, and performing filtering and smoothing calculation on the vehicle speed value.

[0032] For example, the vehicle speed value is obtained from the vehicle communication bus, and the vehicle speed value is filtered and smoothed.

[0033] The commonly used filtering algorithms at present are: average filtering algorithm, median filtering algorithm, first-order filtering algorithm and Kalman filtering algorithm.

[0034] For example, the average value filtering algorithm is a relatively common and simple filtering algorithm. During filtering, the sampling values ​​of N periods are averaged, and the algorithm is very simple. When the value of N is large, the filtered signal is smoother, but the sensitivity is poor. Conversely, when the value of N is small, the filtering smoothing effect is poor, but the sensitivity is good. Advantages: The algorithm is simple, has good suppression effect on periodic interference, has high smoothness, and is suitable for systems with high-frequency vibration. Disadvantages: It has poor suppression effect on abnormal signals and cannot eliminate the influence of pulse interference.

[0035] Optionally, the step of obtaining the vehicle speed value, turning radius and vehicle parameters also includes: obtaining lane lines through a camera device; confirming the lane in which the vehicle is located on the road based on the lane lines, and calculating the current path curvature; and calculating the current turning radius based on the current path curvature.

[0036] Optionally, the vehicle parameters include: the distance from the center of mass to the front and rear axles, the vehicle mass and the lateral stiffness; the step of obtaining the vehicle speed value, turning radius and vehicle parameters also includes: obtaining the distance from the center of mass to the front axle, the distance from the center of mass to the rear axle, the vehicle mass and the lateral stiffness.

[0037] S13: Calculating the slip angle in real time according to the vehicle speed value, turning radius and vehicle parameters.

[0038] For example, vehicle parameters such as the distance from the center of mass to the front axle, the distance from the center of mass to the rear axle, the vehicle mass, and the cornering stiffness are calculated.

[0039] S14: performing a rationality check on the slip angle according to the value of the slip angle and the current state of the vehicle.

[0040] Optionally, the vehicle status includes: vehicle speed, road turning radius and curb weight.

[0041] Optionally, the step of performing a rationality check on the slip angle based on the value of the slip angle and the current state of the vehicle includes: obtaining a slip angle threshold of the vehicle based on the current state of the vehicle; comparing the slip angle with the slip angle threshold; if the slip angle does not exceed the slip angle threshold, confirming that the slip angle is reasonable; if the slip angle exceeds the slip angle threshold, confirming that the slip angle is unreasonable.

[0042] S15: If the verification passes, perform lateral control compensation according to the slip angle.

[0043] S16: If the verification fails, no lateral control compensation is performed.

[0044] For example, after the autonomous driving software determines that the vehicle has entered the autonomous driving function and the vehicle speed is greater than 30 km / h, it starts to estimate the slip angle. If the vehicle has not entered the autonomous driving function or the vehicle speed is less than 30 km / h, no slip angle estimation compensation is performed.

[0045] Slip angle estimation:

[0046] First, obtain the vehicle speed value from the vehicle communication bus, and filter and smooth the speed value.

[0047] Second, after processing the lane lines from the autonomous driving system camera sensor, the vehicle's lane line on the road is calculated based on the lane lines, and the current path curvature is calculated. The current turning radius is calculated based on the curvature.

[0048] 3. Calculate vehicle parameters, including the distance from the center of mass to the front axle, the distance from the center of mass to the rear axle, vehicle mass, cornering stiffness, and other parameters.

[0049] 4. Calculate the instantaneous slip angle in real time based on the above three sets of parameters.

[0050] Based on the calculated slip angle and the vehicle's current state, the instantaneous slip angle is checked for plausibility. If the slip angle passes the check, lateral control compensation is performed. If the slip angle fails the check, no compensation is performed for safety reasons.

[0051] In an autonomous driving system, a software algorithm estimates the slip angle and performs a rationality check on the real-time slip angle estimate. Real-time compensation is applied to the slip angle that passes the rationality check, compensating for inaccurate control caused by tire elastic deformation and providing a more comfortable experience during vehicle dynamic control. If the slip angle fails the rationality check, no lateral slip angle compensation is performed for safety reasons. The slip angle estimation method for autonomous driving according to the present invention can improve safety during cornering at high speeds without requiring additional sensors.

[0052] It should be understood that although the steps in the flowcharts of the accompanying drawings are shown sequentially as indicated by the arrows, these steps are not necessarily executed sequentially in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in rotation or alternation with other steps or at least a portion of the sub-steps or stages of other steps.

[0053] Through the description of the above implementation methods, those skilled in the art can clearly understand that the embodiments of the present invention can be implemented through hardware or by using software plus the necessary general hardware platform. Based on this understanding, the technical solutions of the embodiments of the present invention can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, a USB flash drive, a mobile hard disk, etc.) and includes a number of instructions for enabling a computer device (such as a personal computer, a server, or a network device) to execute the methods described in various implementation scenarios of the embodiments of the present invention.

[0054] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the specific details in the above embodiments. The above embodiments and drawings are exemplary. The modules or processes in the drawings are not necessarily required to implement the embodiments of the present invention and cannot be understood as limitations on the present invention. Within the scope of the technical concept of the present invention, the technical solutions of the present invention can be subjected to various simple modifications and combinations, and these simple modifications and combinations all fall within the scope of protection of the present invention.

Claims

1. A slip angle estimation method for autonomous driving, characterized in that: include: When the vehicle enters automatic driving and the speed of the vehicle exceeds a threshold, performing slip angle estimation; Obtaining the vehicle speed, turning radius, and vehicle parameters of the vehicle; Calculating the slip angle in real time based on the vehicle speed value, turning radius and vehicle parameters; Performing a rationality check on the slip angle according to the value of the slip angle and the current state of the vehicle; If the verification passes, lateral control compensation is performed according to the slip angle; If the verification fails, no lateral control compensation will be performed; The steps of obtaining the vehicle speed value, turning radius and vehicle parameters of the vehicle include: Obtaining a speed value of the vehicle, and performing filtering and smoothing calculation on the speed value; The step of obtaining the vehicle speed value, turning radius and vehicle parameters of the vehicle further includes: Acquire lane lines through a camera device; Determining the lane of the vehicle on the road according to the lane line and calculating the current path curvature; Calculating a current turning radius according to the current path curvature; The vehicle parameters include: the distance from the center of mass to the front and rear axles, the vehicle mass and the lateral stiffness; The step of obtaining the vehicle speed value, turning radius and vehicle parameters of the vehicle further includes: Obtain the distance from the center of mass to the front axle, the distance from the center of mass to the rear axle, the vehicle mass, and the lateral stiffness of the vehicle.

2. The slip angle estimation method for autonomous driving according to claim 1, wherein: Vehicle status includes: vehicle speed, road turning radius and curb weight.

3. The slip angle estimation method for autonomous driving according to claim 1, wherein: When the vehicle enters automatic driving and the speed of the vehicle exceeds a threshold, before the step of estimating the slip angle, the method includes: Acquiring status information of the vehicle, and detecting whether the vehicle meets the autonomous driving requirements based on the status information; When the vehicle meets the autonomous driving requirements and the autonomous driving function is turned on, confirm that the vehicle enters autonomous driving.

4. The slip angle estimation method for autonomous driving according to claim 1, wherein: When the vehicle enters automatic driving and the speed of the vehicle exceeds a threshold, the step of estimating the slip angle includes: When the vehicle does not enter automatic driving, or the vehicle speed does not exceed a threshold, slip angle estimation and compensation are not performed.

5. The slip angle estimation method for autonomous driving according to claim 1, wherein: The step of performing a rationality check on the slip angle according to the value of the slip angle and the current state of the vehicle comprises: Obtaining a slip angle threshold of the vehicle according to the current state of the vehicle; comparing the slip angle with the slip angle threshold; If the slip angle does not exceed the slip angle threshold, confirming that the slip angle is reasonable; If the slip angle exceeds the slip angle threshold, it is determined that the slip angle is unreasonable.

6. The slip angle estimation method for autonomous driving according to claim 1, wherein: The method further comprises: When it is detected that the vehicle enters the automatic driving mode, the step of estimating the slip angle is performed when the vehicle enters the automatic driving mode and the vehicle speed exceeds a threshold.

7. A slip angle estimation system for autonomous driving, characterized in that: The slip angle estimation system for autonomous driving includes: a memory and a processor, wherein a slip angle estimation program is stored in the memory, and when the slip angle estimation program is executed by the processor, the steps of the slip angle estimation system method for autonomous driving are implemented as described in any one of claims 1 to 6.

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