Adaptive cruise control method and system, and vehicle

Abstract

An adaptive cruise control method and system, and a vehicle. The adaptive cruise control method comprises: on the basis of the position of the front vehicle relative to the present vehicle, the type of front vehicle, the speeds of the front vehicle and the rear vehicle and the driving style of the present vehicle, obtaining a field intensity value, wherein the field intensity value is used for representing the degree of attention that the driver of the present vehicle pays to the surrounding driving environment; on the basis of the field intensity value, the type of front vehicle, the distance between the front vehicle and the present vehicle and the driving style, determining the intensity of mutual stimulation of the front vehicle to the present vehicle; and on the basis of the type of front vehicle, the driving style and the intensity of mutual stimulation, calculating an expected acceleration of the present vehicle, wherein the expected acceleration is used for controlling the longitudinal speed of the present vehicle, thereby implementing adaptive cruise control over the present vehicle.

Description

Adaptive cruise control method, system and vehicle CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application No. 202410348569.0 filed on March 26, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application belongs to the field of cruise control technology, and specifically relates to an adaptive cruise control method, system and vehicle. Background Art

[0003] Adaptive Cruise Control (ACC) is a key area of ​​research in active automotive safety and Intelligent Transportation Systems (ITS). ACC uses sensors to perceive the vehicle's surroundings and automatically adjusts speed, allowing the controlled vehicle to follow the vehicle ahead at a safe distance. This reduces driver workload, improves driving safety, and enhances traffic flow. As an assisted driving system, it has found application in mid- to high-end vehicles, playing a positive role in improving driving safety, reducing traffic accidents, and alleviating driver fatigue.

[0004] However, current ACC systems, which focus solely on driving safety, do not adequately consider user comfort. In particular, existing headway control algorithms primarily prioritize following vehicle safety, failing to adequately consider driver and passenger comfort. They also overlook the impact of leading vehicle differences on headway. Therefore, designing an adaptive cruise control method that fully considers both the preceding vehicle and the driver's comfort is crucial. This approach has both theoretical and practical implications for promoting the widespread adoption of adaptive cruise control systems, the implementation of autonomous driving, and the research of intelligent connected vehicles.

[0005] CN202010948774.2, "A Multi-Information Fusion Adaptive Cruise Control System and Method," discloses a multi-information fusion adaptive cruise control system and method. It integrates information from cameras, millimeter-wave radar, maps, and positioning systems to assist drivers in maintaining an appropriate speed range and improve road safety. It only considers relative distance, relative speed, and speed limit to calculate inter-vehicle distances; it does not consider the processing of expected acceleration by the lower-level controller.

[0006] Application CN202211552279.5, "Safety Distance Calculation Method for Adaptive Cruise Control Systems of Intelligent Connected Vehicles," discloses a safety distance calculation method for adaptive cruise control systems of intelligent connected vehicles. This method can calculate an appropriate adaptive cruise safety distance, balancing driving safety and efficiency. However, it suffers from the following issues: Correction parameters for the preceding vehicle type and driver style are directly given without considering real-time updates, potentially leading to inaccurate inter-vehicle distance calculations and impacting cruise safety. Summary of the Invention

[0007] In order to improve the comfort, safety and followability of an adaptive cruise control system during vehicle following driving, the present application proposes an adaptive cruise control method and system.

[0008] An adaptive cruise control method for achieving one of the objectives of this application includes:

[0009] The field strength value is obtained based on the position of the preceding vehicle relative to the vehicle, the preceding vehicle type, the speed of the preceding and following vehicles, and the driving style of the vehicle; the field strength value is used to indicate the driver's attention to the surrounding driving environment;

[0010] determining the mutual stimulation intensity of the preceding vehicle on the own vehicle based on the field strength value, the type of preceding vehicle, the distance between the preceding vehicle and the own vehicle, and the driving style;

[0011] The expected acceleration of the vehicle is calculated based on the type of the preceding vehicle, the driving style, and the mutual stimulation intensity; the expected acceleration is used to control the longitudinal speed of the vehicle, thereby completing the adaptive cruise control of the vehicle.

[0012] The preceding vehicle type refers to the classification of vehicles based on their wheelbase and body length, including large vehicles, medium vehicles, or small vehicles;

[0013] The driving style refers to a driving control mode of a vehicle, including the driver's mentality when driving the vehicle, such as cautious, aggressive or balanced;

[0014] Furthermore, the field strength value includes a first field strength value, and a calculation method thereof includes:

[0015]

[0016] Where:

[0017] E n is the first field strength value;

[0018] is the speed of the vehicle;

[0019] Indicates the speed correction value introduced due to different driving styles;

[0020] Indicates the distance between the preceding vehicle and the host vehicle in the X-axis direction in the host vehicle coordinate system.

[0021] Furthermore, the field strength value includes a second field strength value, and a calculation method thereof includes:

[0022]

[0023] Where:

[0024] is the second field strength value;

[0025] Indicates the distance between the preceding vehicle and the vehicle in the X-axis direction in the vehicle coordinate system of the vehicle;

[0026] The angle formed by the line connecting the position of the preceding vehicle in the vehicle coordinate system, the origin of the coordinate system, and the positive direction of the X-axis;

[0027] To set the weight.

[0028] Furthermore, the method for determining the mutual stimulation intensity includes:

[0029] According to the vehicle speed v n , the second field strength value , the angle 、Calculate the plane psychological field strength of the preceding vehicle type T .

[0030] According to the first field strength value E n , plane psychological field intensity Calculate the mutual stimulation intensity F of the preceding vehicle to the driver of this vehicle n .

[0031] Furthermore, the method for calculating the expected acceleration includes:

[0032] According to the relative speed and distance between the front vehicle and the vehicle, the speed v of the vehicle n , generalized expected headway H exp Get the expected headway SH;

[0033] According to the mutual stimulation intensity F n , the speed of the preceding vehicle and the vehicle itself and , relative speed and distance, preceding vehicle type T, set weight , calculate the expected acceleration based on the expected headway SH.

[0034] An adaptive cruise control system for achieving the second objective of this application includes:

[0035] Field strength acquisition module: derives a field strength value based on the position of the preceding vehicle relative to the host vehicle, the preceding vehicle type, the speeds of the preceding and following vehicles, and the host vehicle's driving style. The field strength value is used to indicate the host vehicle driver's attention to the surrounding driving environment.

[0036] Mutual stimulation intensity acquisition module: used to determine the mutual stimulation intensity of the preceding vehicle on the own vehicle based on the field strength value, the preceding vehicle type, the distance between the preceding vehicle and the own vehicle, and the driving style;

[0037] Expected acceleration calculation module: calculates the expected acceleration of the vehicle based on the preceding vehicle type, driving style, and mutual stimulation intensity;

[0038] Adaptive cruise control module: used to control the longitudinal speed of the vehicle according to the expected acceleration, thereby completing the vehicle's adaptive cruise control.

[0039] A vehicle for achieving the third object of the present application includes a controller configured to execute any step of the above-mentioned adaptive cruise control method.

[0040] Since the current ACC system, which focuses on driving safety as its sole objective, does not adequately consider the user's driving comfort, the existing headway control algorithm primarily considers the safety of following the vehicle, without better balancing the comfort of the driver and passengers. It also ignores the impact of differences in the preceding vehicle on the headway. This application, however, introduces the preceding vehicle type when performing headway control, taking into account the significant differences in the driver's psychological level of tension and anxiety when driving with different preceding vehicle types. By designing an upper-level controller based on the preceding vehicle type and psychological field, the desired acceleration is obtained, and by designing a lower-level vehicle state controller, the desired acceleration is converted into the required braking pressure and throttle opening of the vehicle, thereby achieving control of the vehicle.

[0041] This method addresses the shortcomings of current vehicle spacing control algorithms. Based on a psychological field-based vehicle spacing control algorithm, this method introduces the preceding vehicle type into the design of the upper-level controller and proposes an ACC control method that takes vehicle safety and comfort into consideration. This method enables vehicles with ACC function to adjust the vehicle spacing according to the preceding vehicle type, improving vehicle safety and comfort in operating conditions with complex vehicle types. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG1 is a flow chart of the method and technical solution described in this application;

[0043] FIG2 is a schematic diagram showing the changes in the equipotential lines of the vehicle driver's psychological field in the technical solution of the method described in this application. DETAILED DESCRIPTION

[0044] The following specific implementations are provided to explain the technical solutions of the claims of this application, so that those skilled in the art can understand the claims. The scope of protection of this application is not limited to the specific implementation structures listed below. Any implementation schemes created by those skilled in the art that incorporate the technical solutions of the claims of this application but differ from the following specific implementation schemes are also within the scope of protection of this application.

[0045] Before describing the technical solution of this application, two concepts in this application are explained:

[0046] 1. Driver's psychological field and first field strength:

[0047] The driver's psychological field is a mathematical abstraction of the psychological stress a driver experiences due to the driving environment. The driver's psychological stress is related to the proximity of a point in space (such as the location of the preceding vehicle) to the driver's vehicle, as well as the magnitude of the change in the distance between the preceding vehicle and the driver's vehicle. Along the vehicle's travel direction, psychological stress (i.e., the driver's psychological field strength) is a function of some positive correlation with the inverse of time and distance. In this application, the first field strength of the driver's psychological field is expressed as:

[0048] Formula (1)

[0049] Where:

[0050] E n is the first field strength value;

[0051] is the speed of the vehicle;

[0052] Indicates the speed correction value introduced due to different driving styles. Because under the same speed and type of the vehicle ahead, people with a cautious driving style will keep a larger distance behind the vehicle ahead.

[0053] Indicates the distance between the preceding vehicle and the host vehicle in the X-axis direction in the host vehicle coordinate system.

[0054] 2. Psychological field equipotential lines and second field strength:

[0055] The driver's psychological pressure is also related to the type of the vehicle in front. Furthermore, this application also introduces a second field strength to better express the driver's psychological field strength.

[0056] First, the psychological field equipotential lines are similar to the electric field equipotential lines. Each point on the equipotential line represents the location of the preceding vehicle. When the vehicles are on the same equipotential line, the driver’s first field strength E n equal; when the first field strength is equal, the distance between each point on the equipotential line (representing the position of the preceding vehicle) and the origin of the vehicle coordinate system of the vehicle represents the second field strength value of the driver.

[0057] As shown in FIG1 , the present application provides a technical solution for an adaptive cruise control method, specifically comprising:

[0058] Step 1: Using sensors on the vehicle, the vehicle collects the speed of the preceding vehicle, the vehicle's speed, the vehicle's acceleration, the relative distance between the preceding and succeeding vehicles, and the relative speed between the two vehicles in real time. This information is then passed to an upper-level controller of a time-to-headroom control algorithm based on the preceding vehicle type and the psychological field for processing.

[0059] Step 2: The upper-level controller based on the time-to-headroom algorithm calculates the data collected by the sensors to obtain the expected acceleration of the vehicle under the current conditions. The processing steps of the upper-level controller of the time-to-headroom control algorithm based on the preceding vehicle type and psychological field include:

[0060] Step 2.1: Create a preset plane rectangular coordinate system according to the following method:

[0061] As shown in FIG2 , a plane rectangular coordinate system is formed with the vehicle as the origin, the vehicle's forward direction as the positive direction of the X axis, and the left-hand direction perpendicular to the vehicle's forward direction as the positive direction of the Y axis.

[0062] Step 2.2: Get the real-time speed of the vehicle , the type of vehicle in front and the distance between the vehicle and the vehicle in front Substituting into formula (1) we can get the second field strength of the driver of the vehicle: ;

[0063] Step 2.3: Substitute the real-time position of the preceding vehicle into the following formula to obtain the second field strength of the driver of the vehicle: :

[0064] Formula (2)

[0065] Where:

[0066] is the second field strength value;

[0067] Indicates the distance between the preceding vehicle and the vehicle in the X-axis direction in the vehicle coordinate system of the vehicle;

[0068] is the angle between the position P of the preceding vehicle on the psychological field equipotential line in the vehicle coordinate system of the vehicle and the line OP connecting the origin of the coordinate system and the positive direction of the X axis, and its value range is ;

[0069] To set the weight, the value is related to the vehicle speed, driving style and the type of the preceding vehicle, and the preferred range is (0,1); when the driving style and the preceding vehicle type remain unchanged, the faster the vehicle speed, the more The smaller the value, the more aggressive the driving style, given that the vehicle speed and the type of the preceding vehicle remain unchanged. The smaller, that is ; Under the condition that the driving style and the vehicle speed remain unchanged, the larger the type of vehicle ahead The smaller.

[0070] Step 2.4: Determine the mutual stimulation intensity based on the type of the preceding vehicle, the psychological field equipotential lines of the vehicle, the distance between the preceding and following vehicles, and the driving style.

[0071] 1) Substitute the vehicle speed, the type of the preceding vehicle, and the distance between the preceding and following vehicles into the plane psychological field intensity distribution function shown in formula (3) to determine the plane psychological field intensity. The plane psychological field intensity at any point P (x, y) in the field intensity space of the driver's psychological field is calculated as follows:

[0072] Formula (3)

[0073] Where:

[0074] Indicates the plane psychological field strength value of the driver of this vehicle;

[0075] T represents the field strength correction factor set according to the type of vehicle ahead. The value is determined based on the type of vehicle ahead. The larger the vehicle ahead, the larger the value of T.

[0076] 2) Substituting the preceding vehicle type, the driver's planar psychological field strength, the speeds of the preceding vehicle and the own vehicle, the distance between the preceding vehicle and the own vehicle, and the preceding vehicle type into a preset mutual stimulation intensity function to determine the mutual stimulation intensity.

[0077] The mutual stimulation intensity function is:

[0078] Formula (4)

[0079] Where:

[0080] F n The mutual stimulation intensity of the preceding vehicle relative to the vehicle itself, which is used to characterize the effect of the preceding vehicle on the vehicle. The larger the value, the greater the effect of the preceding vehicle on the driver.

[0081] E n is the field strength value of the driver's psychological field of this vehicle;

[0082] is a function related to the relative speed, direction, and relative distance of the front and rear vehicles, used to represent the driving characteristics of the front vehicle affecting the vehicle; the preferred range is [0,1], and the preferred value is 0.5;

[0083] v n-1 and v n Respectively represent the speed of the preceding vehicle and the speed of the own vehicle;

[0084] Indicates the distance between the preceding vehicle and the host vehicle in the X-axis direction in the host vehicle coordinate system.

[0085] Step 2.5: Determine the expected acceleration of the vehicle according to the type of the preceding vehicle, the driving style, and the mutual stimulation intensity.

[0086] The vehicle following model is constructed by the equipotential lines of the preceding vehicle type and the psychological field, and the vehicle expected acceleration a is determined by introducing the headway constraint. n :

[0087] Formula (5)

[0088] Formula (6)

[0089] Where:

[0090] Δv is the relative speed between the front and rear vehicles;

[0091] l and m are both setting parameters; the preferred range of l is [0, 4], and the preferred value is 2; the preferred range of m is [0, 2], and the preferred value is 1;

[0092] λ1 and λ2 are setting parameters greater than 0. The priority range of λ1 is (0, 20], and the preferred value is λ1=10. The priority range of λ2 is (0, 10], and the preferred value is λ2=5.

[0093] Δv thr is a set value used to indicate the critical value of the speed difference between the front and rear vehicles;

[0094] H exp is the generalized expected headway; the preferred value in this technical solution is 1.5s;

[0095] rec(Δv,Δv thr The specific form is shown in formula (7). Its purpose is to constrain the speed difference between the front and rear vehicles. When the speed difference between the front and rear vehicles is less than or equal to the set value, the value is 1. If the speed difference between the front and rear vehicles is greater than the set value, the value is 0.

[0096] Formula (7)

[0097] The calculation method of the expected acceleration after introducing the headway constraint mainly includes the following steps:

[0098] 1) Set a smaller set value Δv thr =0.5, compare the relative speed difference Δv between the front and rear vehicles to see if it is less than the set value Δv thr ;

[0099] When Δv≦Δv thr When the expected headway SH comes into play, the relative motion between the two vehicles is Δv / Δv l-m =0; Therefore, according to formula (7), we can get rec(Δv,Δv thr） =1, and substituting into formula (6), the expected headway SH is obtained as shown in the following formula (8):

[0100] Formula (8)

[0101] When Δv>Δv thr When , the expected headway SH=0 does not play a role.

[0102] 3) According to formula (5), the desired acceleration a of the vehicle is obtained. n :

[0103] Step 3: Establish a vehicle state controller and obtain the desired acceleration a of the vehicle in the upper controller. n After that, the lower layer calculates the expected acceleration to obtain the required throttle opening and brake pressure.

[0104] Step 3.1. Design the throttle or brake switching logic for the vehicle. Consider that during normal driving, the throttle and brake are controlled separately. It is impossible to press the throttle and brake pedals at the same time. The operating mode is usually determined based on the expected acceleration. When the expected acceleration is positive, the vehicle enters the driving mode, and when the expected acceleration is negative, the vehicle enters the braking mode.

[0105] Step 3.2, acceleration control, includes the following sub-steps:

[0106] Step 3.2.1. According to the car driving equation, get the expected acceleration a n With engine torque T e The relational expression is:

[0107] Formula (9)

[0108] Formula (10)

[0109] in, F is the driving force of the car; f 、F w 、Fi 、F j are rolling resistance, air resistance, slope resistance and acceleration resistance; T e is the engine torque; i g is the transmission ratio; i o is the main reducer transmission ratio; is the mechanical efficiency of the transmission system; r e is the effective radius of the wheel: f is the rolling resistance coefficient; is the road slope angle; C d is the air resistance coefficient; m is the vehicle mass; is the air density; A is the frontal area of ​​the car; is the vehicle rotation mass conversion factor;

[0110] Step 3.2.2: Establish an inverse engine model. Use the engine torque Te and engine speed n obtained by the upper controller to obtain the desired acceleration. Check the inverse engine model and obtain the throttle opening a as shown below: des Calculation formula:

[0111] Formula (11)

[0112] Step 3.3, braking control: When the car is moving, the braking force is derived according to the car driving equation, as shown in the following formula:

[0113] Formula (12)

[0114] The vehicle's braking pressure P b and vehicle braking force F b The relationship expression is:

[0115] Formula (13)

[0116] Among them, P b is the pressure of the vehicle's brake master cylinder, F b is the vehicle braking force, K is the fixed ratio of the vehicle braking force to the vehicle brake master cylinder pressure. b and throttle opening a des Transmitted to the vehicle, thereby achieving control of the vehicle's longitudinal speed.

[0117] It should be understood that the size of the serial numbers of each step in the above technical solution does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the technical solution of this application.

[0118] The technical solution of this application also provides an adaptive cruise control system, comprising:

[0119] Field strength acquisition module: derives a field strength value based on the position of the preceding vehicle relative to the host vehicle, the preceding vehicle type, the speeds of the preceding and following vehicles, and the host vehicle's driving style. The field strength value is used to indicate the host vehicle driver's attention to the surrounding driving environment.

[0120] Mutual stimulation intensity acquisition module: used to determine the mutual stimulation intensity of the preceding vehicle on the own vehicle based on the field strength value, the preceding vehicle type, the distance between the preceding vehicle and the own vehicle, and the driving style;

[0121] Expected acceleration calculation module: calculates the expected acceleration of the vehicle based on the preceding vehicle type, driving style, and mutual stimulation intensity;

[0122] Adaptive cruise control module: used to control the longitudinal speed of the vehicle according to the expected acceleration, thereby completing the vehicle's adaptive cruise control.

[0123] The technical solution of the present application also includes a vehicle, which includes a controller, and the controller is configured to execute any step of the above-mentioned adaptive cruise control method, thereby realizing adaptive cruise control of the vehicle.

[0124] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. An adaptive cruise control method, characterized in that: include: The field strength value is obtained based on the position of the preceding vehicle relative to the vehicle, the preceding vehicle type, the speed of the preceding and following vehicles, and the driving style of the vehicle; The field strength value is used to indicate the driver's attention to the surrounding driving environment; determining the mutual stimulation intensity of the preceding vehicle on the own vehicle based on the field strength value, the type of preceding vehicle, the distance between the preceding vehicle and the own vehicle, and the driving style; The expected acceleration of the vehicle is calculated based on the type of the preceding vehicle, the driving style, and the mutual stimulation intensity; the expected acceleration is used to control the longitudinal speed of the vehicle, thereby completing the adaptive cruise control of the vehicle.

2. The adaptive cruise control method according to claim 1, wherein: The field strength value includes a first field strength value, and a calculation method thereof includes: ， Where: E n is the first field strength value; is the speed of the vehicle; Indicates the speed correction value introduced due to different driving styles; Indicates the distance between the preceding vehicle and the host vehicle in the X-axis direction in the host vehicle coordinate system.

3. The adaptive cruise control method according to claim 2, wherein: The field strength value includes a second field strength value, and a calculation method thereof includes: ， Where: is the second field strength value; Indicates the distance between the preceding vehicle and the vehicle in the X-axis direction in the vehicle coordinate system of the vehicle; The angle formed by the line connecting the position of the preceding vehicle in the vehicle coordinate system, the origin of the coordinate system, and the positive direction of the X-axis; To set the weight.

4. The adaptive cruise control method according to claim 3, wherein: The method for determining the mutual stimulation intensity includes: According to the vehicle speed v n , the second field strength value , the angle 、Calculate the plane psychological field strength of the preceding vehicle type T ； According to the first field strength value E n , plane psychological field intensity Calculate the mutual stimulation intensity F of the preceding vehicle to the driver of this vehicle n .

5. The adaptive cruise control method according to claim 4, wherein: The mutual stimulation intensity F n The calculation methods include: ， Where: is the set value; v n-1 and v n Respectively represent the speed of the preceding vehicle and the speed of the own vehicle; Indicates the distance between the preceding vehicle and the vehicle in the X-axis direction in the vehicle coordinate system of the vehicle; T indicates the type of the preceding vehicle.

6. The adaptive cruise control method according to claim 4, wherein: The method for calculating the expected acceleration includes: According to the relative speed and distance between the front vehicle and the vehicle, the speed v of the vehicle n , generalized expected headway H exp Get the expected headway SH; According to the mutual stimulation intensity F n , the speed v of the preceding vehicle and the vehicle itself n-1 and v n , relative speed and distance, preceding vehicle type T, set weight , calculate the expected acceleration based on the expected headway SH.

7. The adaptive cruise control method according to claim 1, wherein: The method for calculating the expected acceleration includes: ， Where: F n for the mutual stimulation intensity; λ1, l and m are all set parameters; v n-1 and v n Respectively represent the speed of the preceding vehicle and the speed of the own vehicle; Indicates the distance between the preceding vehicle and the vehicle in the X-axis direction in the vehicle coordinate system of the vehicle; T is the type of the preceding vehicle; To set weights; The angle formed by the line connecting the position of the preceding vehicle in the vehicle coordinate system, the origin of the coordinate system, and the positive direction of the X-axis; Δv is the relative speed between the preceding vehicle and the vehicle itself; SH is the expected headway.

8. The adaptive cruise control method according to claim 6, wherein: The method for calculating the expected headway SH includes: ， Where: rec(Δv,Δv thr ) is the relative speed of the two vehicles Δv and the set value Δv thr The set value is obtained by the difference between λ2 is the setting parameter; H exp is the generalized expected headway; Indicates the distance between the preceding vehicle and the vehicle in the X-axis direction in the vehicle coordinate system of the vehicle; v n Indicates the vehicle's speed.

9. An adaptive cruise control system using the method of claim 1, characterized in that: include: Field strength acquisition module: derives the field strength value based on the position of the preceding vehicle relative to the vehicle, the preceding vehicle type, the speed of the preceding and following vehicles, and the driving style of the vehicle; The field strength value is used to indicate the driver's attention to the surrounding driving environment; Mutual stimulation intensity acquisition module: used to determine the mutual stimulation intensity of the preceding vehicle on the own vehicle based on the field strength value, the preceding vehicle type, the distance between the preceding vehicle and the own vehicle, and the driving style; Expected acceleration calculation module: calculates the expected acceleration of the vehicle based on the preceding vehicle type, driving style, and mutual stimulation intensity; Adaptive cruise control module: used to control the longitudinal speed of the vehicle according to the expected acceleration, thereby completing the vehicle's adaptive cruise control.

10. A vehicle, characterized in that: The method comprises a controller configured to execute the adaptive cruise control method according to any one of claims 1 to 8.

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