A lane keeping assist method and system with integrated corner control

Abstract

This invention belongs to the field of intelligent driving technology for automobiles, and discloses a lane keeping assist method and system with integrated steering angle control: Step 1, acquire the vehicle speed V and yaw angle α through sensors, and with the camera as the coordinate origin, acquire the lateral distance Dist from the coordinate origin to the intersection point of the horizontal axis and the lane departure line, wherein the coordinate system uses the vehicle centerline as the vertical axis; Step 2, determine the lateral distance Dist and the lateral departure speed V. y If preset conditions are met, the Lane Keeping Assist (LKA) system is activated. Step 3: Calculate the overall steering angle and use it as the input control value for the Lane Keeping Assist (LKA) system. This invention solves the problems of low accuracy and weak robustness in lane keeping assist control.

Description

Technical Field

[0001] This invention belongs to the field of intelligent driving technology for automobiles, and specifically relates to a lane keeping assist method and system with integrated steering angle control. Background Technology

[0002] Lane Keeping Assist (LKA) is a lateral motion control driver assistance function used to help the driver keep the vehicle within the lane lines when the driver unintentionally deviates from the lane. It primarily uses a forward-facing camera to identify lane boundaries and controls the activation and deactivation of the lane keeping system based on the distance between the vehicle's position within the lane and the lane boundaries. When the camera detects that the vehicle has deviated from its lane based on the boundary lines, LKA automatically adjusts the steering wheel to correct the direction and return the vehicle to the lane.

[0003] In existing technologies, such as Chinese patent CN114494360A, a lane keeping control method, device, equipment, and readable storage medium are disclosed. These mainly rely on simple open-loop or closed-loop control. Pure closed-loop control cannot guarantee a smooth and rapid suppression of vehicle deviation within a specified time. To avoid repeated and prolonged interference with the driver, LKA (Lane Keeping Assist) is usually a short-term intervention function, activated only when the vehicle has already crossed or is about to cross the lane line. At this time, the lateral displacement of the vehicle from the lane centerline and the angle with the pre-aimed lane center point are relatively large. If closed-loop control is used, a large turning angle command and a large correction amplitude are necessary to quickly suppress vehicle deviation. On the other hand, smooth control cannot quickly pull the vehicle back within a specified time, resulting in the vehicle deviating too much from one side of the lane line, posing a safety hazard.

[0004] Therefore, providing a lane keeping assist method and system that integrates steering angle control to improve the accuracy and robustness of LKA control is an urgent problem to be solved. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a lane keeping assist method and system with integrated steering angle control.

[0006] In a first aspect, the present invention provides a lane keeping assist method integrating steering angle control, the method comprising the following steps:

[0007] Step 1: Obtain the vehicle speed V and yaw angle α through the sensor, and with the camera as the origin of the coordinate system, obtain the lateral distance Dist from the origin of the coordinate system to the intersection of the horizontal axis and the lane line deviating from the side. The coordinate system uses the vehicle centerline as the vertical axis.

[0008] Step 2: Determine whether the lateral distance Dist and the lateral deviation speed Vy meet preset conditions. If the preset conditions are met, activate the Lane Keeping Assist (LKA) system. The lateral deviation speed Vy is calculated using the following formula: V y =V×α;

[0009] Step 3: Calculate the overall steering angle and use the overall steering angle as the input control quantity of the Lane Assist (LKA) system.

[0010] Specifically, in step 2, the lateral distance Dist and the lateral deviation velocity V are determined. y Whether the preset conditions are met includes:

[0011] Determine whether the lateral distance Dist is less than a threshold;

[0012] Determine the lateral deviation velocity V y Is it greater than 0?

[0013] When the lateral distance Dist is less than the threshold, and the lateral deviation velocity V y When the value is greater than 0, the preset condition is met.

[0014] Specifically, after activating the Lane Keeping Assist (LKA) system, the lane crossing time (TLC) is calculated, and the cumulative activation time (t) is also calculated. The formula for calculating the lane crossing time (TLC) is as follows:

[0015] Specifically, the formula for calculating the combined turning angle is: SWA = k1·SWA1 + k2·SWA2.

[0016] Wherein, SWA is the comprehensive rotation angle, k1 and k2 are weighting coefficients, SWA1 is the target rotation angle of the correction stage of open-loop control, and SWA2 is the target rotation angle of the homing stage of closed-loop control.

[0017] Specifically, when the activation cumulative time t is less than or equal to TLC, k1 = 1, k2 = 0;

[0018] When the cumulative activation time t is greater than TLC and less than 2TLC, k1 = 1 - k2;

[0019] When the cumulative activation time t is greater than or equal to 2TLC, k1 = 0 and k2 = 1.

[0020] Specifically, when the Lane Keeping Assist (LKA) system is not activated, the combined steering angle is 0.

[0021] Secondly, the present invention also provides a lane keeping assist system with integrated steering angle control, the system comprising:

[0022] The information acquisition module is used to acquire the vehicle speed V and yaw angle α through sensors, and to acquire the lateral distance Dist from the origin of the coordinate system to the intersection of the horizontal axis and the lane line deviating from the camera, with the vehicle centerline as the vertical axis.

[0023] The condition judgment module is used to determine whether the lateral distance Dist and the lateral deviation speed Vy meet preset conditions. When the preset conditions are met, the Lane Keeping Assist (LKA) system is activated. The lateral deviation speed Vy is calculated using the following formula: V y =V×α;

[0024] The adjustment module is used to calculate the overall steering angle and use the overall steering angle as the input control quantity of the lane assist LKA system.

[0025] Thirdly, the present invention provides a computer storage medium storing program instructions, wherein the program instructions, when executed, control the device where the computer storage medium is located to execute any of the above-mentioned lane keeping assist methods for integrated steering angle control.

[0026] Fourthly, the present invention provides a processor for running a program, wherein the program executes the lane keeping assist method for integrated steering angle control described above during runtime.

[0027] Fifthly, the present invention provides a vehicle employing a lane keeping assist method with integrated steering angle control as described above.

[0028] This invention discloses a lane keeping assist method and system with integrated steering angle control. The lane keeping assist (LKA) control process is divided into two stages: correction and straightening. The correction stage is an open-loop control designed to suppress the vehicle from continuing to deviate during the lane crossing time (TLC) and straighten the vehicle. The straightening stage is a PID closed-loop control that pulls the vehicle back to the center of the lane, achieving high precision and strong robustness in control. At the same time, through the integrated steering angle control algorithm, the control abrupt changes caused by different algorithms in the two stages are avoided, so that the steering angle control commands of the two stages can be smoothly and continuously transitioned. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 A flowchart of a lane keeping assist method with integrated steering angle control according to the present invention;

[0031] Figure 2 This is a schematic diagram of lateral distance and yaw angle in an embodiment of the present invention;

[0032] Figure 3 This is an LKA corner command curve diagram in an embodiment of the present invention;

[0033] Figure 4 This is a flowchart of the corner integrated control algorithm in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the structure of a lane keeping assist system with integrated steering angle control according to the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the specific embodiments described herein are merely illustrative of the invention and represent only a portion, not all, of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0036] It should be noted that if the embodiments of the present invention involve descriptions such as "first" and "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0037] Figure 1 The diagram shows a flowchart of an embodiment of a lane keeping assist method with integrated steering angle control provided by the present invention. The flowchart specifically includes the following steps:

[0038] Step 1: Obtain the vehicle speed V and yaw angle α through the sensor, and with the camera as the origin of the coordinate system, obtain the lateral distance Dist from the origin of the coordinate system to the intersection of the horizontal axis and the lane line deviating from the side. The coordinate system uses the vehicle centerline as the vertical axis.

[0039] Preferably, the direction of the vehicle speed V is consistent with the direction of vehicle travel.

[0040] If a vehicle veers off the side lane line, veering to the left will lead to the left lane line, and the lateral distance Dist is the distance to the left lane line. If veering to the right will lead to the right lane line, and the lateral distance Dist is the distance to the right lane line.

[0041] A schematic diagram for calculating the lateral distance Dist and the yaw angle α is shown below. Figure 2 As shown.

[0042] The origin of the coordinate system is A. The lane line the vehicle veers off from is the right lane line. The intersection of the horizontal axis and the lane line veers off from is B. The distance between points A and B is the lateral distance Dist. The yaw angle α is the angle between the lane line tangent at point A and the line perpendicular to the horizontal axis at point A.

[0043] Step 2: Determine whether the lateral distance Dist and the lateral deviation speed Vy meet preset conditions. If the preset conditions are met, activate the Lane Keeping Assist (LKA) system. The lateral deviation speed Vy... y The calculation formula is: V y =V×α.

[0044] Specifically, in step 2, the lateral distance Dist and the lateral deviation velocity V are determined. y Whether the preset conditions are met includes:

[0045] Determine whether the lateral distance Dist is less than a threshold;

[0046] Determine the lateral deviation velocity V y Is it greater than 0?

[0047] When the lateral distance Dist is less than the threshold, and the lateral deviation velocity V y When the value is greater than 0, the preset condition is met.

[0048] When the lateral distance Dist and the lateral deviation velocity V y When the set conditions are met simultaneously, the lateral distance Dist and the lateral deviation velocity V y The preset conditions are met. If the lateral distance Dist and the lateral deviation velocity V... y If any of the set conditions are not met, the preset conditions will not be met, and the Lane Keeping Assist (LKA) system will not be activated.

[0049] Specifically, after activating the Lane Keeping Assist (LKA) system, the lane crossing time (TLC) is calculated, and the cumulative activation time (t) is also calculated. The formula for calculating the lane crossing time (TLC) is as follows:

[0050] When the lane keeping assist system is activated, the lane crossing time TLC is calculated, and the time t from the start of activation is also calculated, and the activation time is timed.

[0051] Step 3: Calculate the overall steering angle and use the overall steering angle as the input control quantity of the Lane Assist (LKA) system.

[0052] Specifically, the formula for calculating the combined turning angle is: SWA = k1·SWA1 + k2·SWA2.

[0053] Wherein, SWA is the comprehensive rotation angle, k1 and k2 are weighting coefficients, SWA1 is the target rotation angle of the correction stage of open-loop control, and SWA2 is the target rotation angle of the homing stage of closed-loop control.

[0054] Specifically, when the activation cumulative time t is less than or equal to TLC, k1 = 1, k2 = 0;

[0055] When the cumulative activation time t is greater than TLC and less than 2TLC, k1 = 1 - k2;

[0056] When the cumulative activation time t is greater than or equal to 2TLC, k1 = 0 and k2 = 1.

[0057] Timing begins from the activation of the trigger function. When the accumulated time t is less than or equal to the TLC time, the system is in the first stage of pure open-loop control, suppressing the vehicle from further deviation within the TLC time. The coefficients k1 and k2 are 1 and 0, respectively. When the accumulated time t is greater than the TLC time but less than 2TLC times, the system is in the transition stage, where open-loop and closed-loop control coexist. The weighting coefficients of the two stages of control are calculated according to the formulas for k1 and k2, resulting in the proportion of control commands for the two stages. When the accumulated time t is greater than or equal to 2TLC times, the system fully transitions to the second stage of control, with k1 and k2 set to 0 and 1, smoothly transitioning from the first stage of control to the second stage of control.

[0058] Based on k1 and k2 from the first stage, transition stage, and second stage described above, calculate the combined cornering command:

[0059] SWA = k1·SWA1 + k2·SWA2.

[0060] Specifically, when the Lane Keeping Assist (LKA) system is not activated, the combined steering angle is 0.

[0061] The LKA turning command curve is as follows: Figure 3 As shown.

[0062] The flowchart of the angle integrated control algorithm is as follows: Figure 4 As shown.

[0063] Figure 5 The diagram shown is a structural schematic of an embodiment of a lane keeping assist system with integrated steering angle control provided by the present invention. Figure 5 As shown, the system includes:

[0064] The information acquisition module is used to acquire the vehicle speed V and yaw angle α through sensors, and to acquire the lateral distance Dist from the origin of the coordinate system to the intersection of the horizontal axis and the lane line deviating from the camera, with the vehicle centerline as the vertical axis.

[0065] The condition judgment module is used to determine the lateral distance Dist and the lateral deviation velocity V. y If the preset conditions are met, the Lane Keeping Assist (LKA) system is activated, wherein the lateral deviation speed V... y The calculation formula is: V y =V×α.

[0066] The adjustment module is used to calculate the overall steering angle and use the overall steering angle as the input control quantity of the lane assist LKA system.

[0067] Preferably, the direction of the vehicle speed V is consistent with the direction of vehicle travel.

[0068] If a vehicle veers off the side lane line, veering to the left will lead to the left lane line, and the lateral distance Dist is the distance to the left lane line. If veering to the right will lead to the right lane line, and the lateral distance Dist is the distance to the right lane line.

[0069] Specifically, the lateral distance Dist and the lateral deviation velocity V are determined. y Whether the preset conditions are met includes:

[0070] Determine whether the lateral distance Dist is less than a threshold;

[0071] Determine the lateral deviation velocity V y Is it greater than 0?

[0072] When the lateral distance Dist is less than the threshold, and the lateral deviation velocity V y When the value is greater than 0, the preset condition is met.

[0073] When the lateral distance Dist and the lateral deviation velocity V y When the set conditions are met simultaneously, the lateral distance Dist and the lateral deviation velocity V y The preset conditions are met. If the lateral distance Dist and the lateral deviation velocity V... y If any of the set conditions are not met, the preset conditions will not be met, and the Lane Keeping Assist (LKA) system will not be activated.

[0074] Specifically, after activating the Lane Keeping Assist (LKA) system, the lane crossing time (TLC) is calculated, and the cumulative activation time (t) is also calculated. The formula for calculating the lane crossing time (TLC) is as follows:

[0075] When the lane keeping assist system is activated, the lane crossing time TLC is calculated, and the time t from the start of activation is also calculated, and the activation time is timed.

[0076] Specifically, the formula for calculating the combined turning angle is: SWA = k1·SWA1 + k2·SWA2.

[0077] Wherein, SWA is the comprehensive rotation angle, k1 and k2 are weighting coefficients, SWA1 is the target rotation angle of the correction stage of open-loop control, and SWA2 is the target rotation angle of the homing stage of closed-loop control.

[0078] Specifically, when the activation cumulative time t is less than or equal to TLC, k1 = 1, k2 = 0;

[0079] When the cumulative activation time t is greater than TLC and less than 2TLC, k1 = 1 - k2;

[0080] When the cumulative activation time t is greater than or equal to 2TLC, k1 = 0 and k2 = 1.

[0081] Timing begins from the activation of the trigger function. When the accumulated time t is less than or equal to the TLC time, the system is in the first stage of pure open-loop control, suppressing the vehicle from further deviation within the TLC time. The coefficients k1 and k2 are 1 and 0, respectively. When the accumulated time t is greater than the TLC time but less than 2TLC times, the system is in the transition stage, where open-loop and closed-loop control coexist. The weighting coefficients of the two stages of control are calculated according to the formulas for k1 and k2, resulting in the proportion of control commands for the two stages. When the accumulated time t is greater than or equal to 2TLC times, the system fully transitions to the second stage of control, with k1 and k2 set to 0 and 1, smoothly transitioning from the first stage of control to the second stage of control.

[0082] Based on k1 and k2 from the first stage, transition stage, and second stage described above, calculate the combined cornering command:

[0083] SWA = k1·SWA1 + k2·SWA2.

[0084] Specifically, when the Lane Keeping Assist (LKA) system is not activated, the combined steering angle is 0.

[0085] According to another aspect of the present invention, a computer storage medium is provided, which stores program instructions, wherein the program instructions, when executed, control the device where the computer storage medium is located to execute the lane keeping assist method of integrated steering angle control described above.

[0086] According to another aspect of the present invention, a processor is provided for running a program, wherein the program executes the lane keeping assist method for integrated steering angle control described above.

[0087] According to another aspect of the present invention, a vehicle is provided that employs a lane keeping assist method with integrated steering angle control as described above.

[0088] It should be understood that although the steps in the flowcharts of the various embodiments of the present invention are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated 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 steps in the various embodiments may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least a portion of the sub-steps or stages of other steps.

[0089] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A lane keeping assist method integrating steering angle control, characterized in that, Includes the following steps: Step 1: Obtain the vehicle speed V and yaw angle α through the sensor, and with the camera as the origin of the coordinate system, obtain the lateral distance Dist from the origin of the coordinate system to the intersection of the horizontal axis and the lane line deviating from the side. The coordinate system uses the vehicle centerline as the vertical axis. Step 2: Determine whether the lateral distance Dist and the lateral deviation speed Vy meet preset conditions. If the preset conditions are met, activate the Lane Keeping Assist (LKA) system. The formula for calculating the lateral deviation speed Vy is: ; Step 3: Calculate the overall steering angle and use the overall steering angle as the input control quantity for the Lane Assist (LKA) system; After activating the Lane Keeping Assist (LKA) system, the lane crossing time (TLC) is calculated, and the cumulative activation time (t) is also calculated. The formula for calculating the lane crossing time (TLC) is as follows: ; The formula for calculating the combined rotation angle is: Wherein, SWA is the combined turning angle. and For weighting coefficients, SWA1 is the target rotation angle in the correction stage of open-loop control, and SWA2 is the target rotation angle in the homing stage of closed-loop control. When the cumulative activation time t is less than or equal to TLC, k1=1, k2=0; when the cumulative activation time t is greater than TLC and less than 2TLC, k1=1-k2; when the activation cumulative time t is greater than or equal to 2TLC, k1=0, k2=1.

2. The lane keeping assist method with integrated steering angle control according to claim 1, characterized in that, In step 2, the lateral distance Dist and the lateral deviation velocity V are determined. y Whether the preset conditions are met includes: Determine whether the lateral distance Dist is less than a threshold; Determine the lateral deviation velocity V y Is it greater than 0? When the lateral distance Dist is less than the threshold, and the lateral deviation velocity V y When the value is greater than 0, the preset condition is met.

3. The lane keeping assist method with integrated steering angle control according to claim 1, characterized in that, When the Lane Keeping Assist (LKA) system is not activated, the combined steering angle is 0.

4. A lane keeping assist system with integrated steering angle control, used to implement the lane keeping assist method with integrated steering angle control as described in any one of claims 1-3, characterized in that, include: The information acquisition module is used to acquire the vehicle speed V and yaw angle α through sensors, and to acquire the lateral distance Dist from the origin of the coordinate system to the intersection of the horizontal axis and the lane line deviating from the camera, with the vehicle centerline as the vertical axis. The condition judgment module is used to determine whether the lateral distance Dist and the lateral deviation speed Vy meet preset conditions. When the preset conditions are met, the Lane Keeping Assist (LKA) system is activated. The formula for calculating the lateral deviation speed Vy is: ; The adjustment module is used to calculate the overall steering angle and use the overall steering angle as the input control quantity of the lane assist LKA system.

5. A computer storage medium, characterized in that, The computer storage medium stores program instructions, wherein when the program instructions are executed, the device where the computer storage medium is located is controlled to execute the lane keeping assist method of integrated steering angle control as described in any one of claims 1 to 3.

6. A processor, characterized in that, The processor is used to run a program, wherein the program executes the lane keeping assist method with integrated steering angle control as described in any one of claims 1 to 3.

7. A vehicle, characterized in that, The lane keeping assist method with integrated steering angle control as described in any one of claims 1 to 3 is adopted.

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