Drift assist control method, apparatus, vehicle, and storage medium

Abstract

The embodiment of the application provides a drift auxiliary control method and device, a vehicle and a storage medium, and relates to the technical field of intelligent driving. The method comprises the following steps: when the vehicle meets the drift auxiliary control condition, obtaining the working mode of drift auxiliary determined by the driver and the control intervention intensity of drift auxiliary; determining the steering wheel angle target according to the control intervention intensity; and performing drift auxiliary control on the vehicle according to the working mode and the steering wheel angle target, so that the vehicle can maintain a stable drift state under the premise of meeting the needs of different drivers for drift driving, and the vehicle can successfully realize drift.

Description

Technical Field

[0001] This application relates to the field of intelligent driving technology, and in particular, to a drift assist control method, device, vehicle, and storage medium. Background Technology

[0002] Drifting is a form of vehicle motion. Essentially, drifting increases the driving force on the rear axle, causing a large longitudinal slip ratio (slip ratio refers to the proportion of slippage in wheel motion). This prevents the rear axle from providing sufficient lateral force, putting the vehicle in a near-instable state, with a sharp increase in the vehicle's sideslip angle. The driver can maintain this near-instability state, keeping the sideslip angle large but stable, thus making the vehicle appear to glide sideways through a corner.

[0003] like Figure 1 As shown, drifting involves three steps: entering a drift, maintaining a drift, and ending a drift. The driver can induce a near-unstable state by sharply turning the steering wheel, flooring the accelerator, and applying the auxiliary brakes (commonly known as the handbrake), causing the vehicle's sideslip angle to increase rapidly. The driver can then adjust the throttle to control the rear-wheel drive, keeping the rear wheels in a high slip ratio driving state, while counter-steering to bring the front wheels into the linear zone of tire lateral force, controlling the sideslip angle to prevent further increase and achieving a relatively stable state, thus allowing the vehicle to drift through a corner. Finally, the driver can adjust the throttle and steering wheel to reduce the sideslip angle, allowing the vehicle to return to stable straight-line driving, at which point the drift ends.

[0004] Common mistakes during drifting typically fall into two categories: First, during the maintenance and termination of the drift, the vehicle's sideslip angle increases too rapidly, making it impossible for the driver to regain stability through steering and throttle inputs, resulting in a fishtail and loss of control. This usually occurs because the driver's counter-steering speed is insufficient when the vehicle begins to drift. Second, during the drift entry phase, due to insufficient initial steering wheel rotation or insufficient rear-wheel drive, the vehicle returns to a near-straight-line stable state before reaching the near-instability drift state described above. Therefore, successfully completing a drift is quite challenging for a driver.

[0005] To ensure a vehicle successfully completes a drift, related technologies have proposed methods that allow setting a drift path so the vehicle can autonomously follow it. While this method ensures a successful drift, it prevents the driver from participating in the drifting process, depriving highly skilled drivers (e.g., professional race car drivers or excellent drift drivers) of the enjoyment of autonomous drifting.

[0006] Currently, there is no solution in this field that can simultaneously provide drivers with the enjoyment of participating in vehicle drifting and ensure the successful completion of the drift. Summary of the Invention

[0007] This application provides a drift assist control method, device, vehicle, and storage medium to improve the above-mentioned problems.

[0008] In a first aspect, embodiments of this application provide a drift assist control method. The method includes: if a vehicle meets drift assist control conditions, acquiring a drift assist operating mode and a drift assist control intervention intensity determined by the driver; determining a steering wheel angle target based on the control intervention intensity, wherein the steering wheel angle target is a steering wheel position that maintains the vehicle in a stable drift state; and performing drift assist control on the vehicle based on the operating mode and the steering wheel angle target.

[0009] Secondly, embodiments of this application provide a drift assist control device. The device includes: an information acquisition module, configured to acquire, if the vehicle meets drift assist control conditions, a drift assist operating mode and a drift assist control intervention intensity determined by the driver; a target determination module, configured to determine a steering wheel angle target based on the control intervention intensity, wherein the steering wheel angle target is a steering wheel position that maintains the vehicle in a stable drift state; and a drift control module, configured to perform drift assist control on the vehicle based on the operating mode and the steering wheel angle target.

[0010] Thirdly, embodiments of this application provide a vehicle. The vehicle includes a memory, one or more processors, and one or more application programs. The one or more application programs are stored in the memory and configured to, when invoked by one or more processors, cause the one or more processors to execute the methods provided in embodiments of this application.

[0011] Fourthly, embodiments of this application provide a computer-readable storage medium. This computer-readable storage medium stores program code that, when invoked by a processor, causes the processor to execute the method provided in embodiments of this application.

[0012] This application provides a drift assist control method, device, vehicle, and storage medium. When the vehicle meets the drift assist conditions, the method performs drift assist control on the vehicle according to the drift assist working mode and control intervention intensity determined by the driver. This ensures that the vehicle maintains a stable drift state while meeting the drift driving needs of different drivers, thereby ensuring that the vehicle successfully drifts. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of vehicle drifting provided in an exemplary embodiment of this application;

[0015] Figure 2 This is a schematic diagram illustrating an application scenario of the drift-assisted control method provided in an exemplary embodiment of this application;

[0016] Figure 3 This is a schematic diagram of the human-computer interaction interface of a human-computer interaction device provided in an exemplary embodiment of this application;

[0017] Figure 4 This is a schematic diagram of the human-computer interaction interface of a human-computer interaction device provided in another exemplary embodiment of this application;

[0018] Figure 5 This is a schematic flowchart of a drift-assisted control method provided in an embodiment of this application;

[0019] Figure 6 This is a flowchart illustrating a drift-assisted control method provided in another embodiment of this application;

[0020] Figure 7 This is a schematic diagram of a front wheel steering angle-steering wheel angle mapping table provided in an exemplary embodiment of this application;

[0021] Figure 8 This is a schematic diagram of a vehicle force analysis diagram provided in an exemplary embodiment of this application;

[0022] Figure 9 This is a schematic diagram of the force analysis diagram of a vehicle provided in another exemplary embodiment of this application;

[0023] Figure 10 This is a schematic diagram of a steering torque-gain mapping table provided in an exemplary embodiment of this application;

[0024] Figure 11 This is a flowchart illustrating a drift-assisted control method provided in an exemplary embodiment of this application;

[0025] Figure 12 This is a structural block diagram of a drift assist control device provided in an embodiment of this application;

[0026] Figure 13 This is a structural block diagram of a vehicle provided in one embodiment of this application;

[0027] Figure 14 This is a structural block diagram of a computer-readable storage medium provided in an embodiment of this application. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0029] Please see Figure 2 , Figure 2 This is a schematic diagram illustrating an application scenario of the drift assist control method provided in an exemplary embodiment of this application. The drift assist control system 100 includes a positioning device 110, a center of gravity sideslip angle estimation module 120, a human-machine interface device 130, a drift assist module 140, and a steering system 150. The positioning device 110, the center of gravity sideslip angle estimation module 120, the human-machine interface device 130, the drift assist module 140, and the steering system 150 can be installed in the same vehicle and communicate with each other to achieve data interaction. The drift assist control system 100 can be an Advanced Driver Assistance System (ADAS).

[0030] The positioning device 110 can measure the vehicle's latitude and longitude information based on satellite positioning principles and send the measured latitude and longitude information to the drift assistance module 140. The positioning device 110 may include a Global Positioning System (GPS) and other vehicle navigation systems, without specific limitations. The positioning device 110 can obtain information such as the vehicle's current yaw rate and lateral acceleration through GPS and the vehicle navigation system, and send the obtained yaw rate and lateral acceleration information to the center of gravity sideslip angle estimation module 120.

[0031] The center-of-gravity sideslip angle estimation module 120 can communicate with a vehicle communication network, such as a Controller Area Network (CAN). The module 120 can obtain vehicle status information, such as the current steering wheel angle and vehicle speed, through the vehicle communication network. The module 120 can also receive information such as yaw rate and lateral acceleration sent by the positioning device 110.

[0032] The center of gravity sideslip angle estimation module 120 includes a vehicle dynamics model. Based on the vehicle state such as the steering wheel impact angle and vehicle speed, as well as the yaw rate and lateral acceleration, the center of gravity sideslip angle estimation module 120 uses the dynamics model to estimate the vehicle's current actual center of gravity sideslip angle, actual front wheel steering angle, actual front axle sideslip angle, and actual rear axle lateral force.

[0033] The center of gravity deflection estimation module 120 also includes a Kalman filter established based on the vehicle dynamics model and the Dugoff tire model. By inputting the yaw rate and lateral acceleration mentioned above into the Kalman filter, information such as the road adhesion coefficient of the front axle and the rear axle, the lateral velocity at the center of gravity, and the yaw rate can be obtained.

[0034] The center of gravity sideslip angle estimation module 120 can send information such as the actual center of gravity sideslip angle, actual front wheel steering angle, actual front axle sideslip angle, actual rear axle lateral force, road surface adhesion coefficient of the front and rear axles, lateral velocity at the center of gravity, and yaw rate to the drift assist module 140.

[0035] The human-machine interface device 130 can provide a human-machine interface. The human-machine interface can display modules for setting the drift assist operating mode and for setting the control intervention intensity of the drift assist. The human-machine interface device 130 can also display other information according to the instructions of the drift assist module 140, such as the actual sideslip angle of the center of gravity mentioned above.

[0036] In some implementations, the module for setting the drift assist operating mode may include at least two virtual buttons, each corresponding to a different operating mode. For example, please refer to [link to example]. Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the human-computer interaction interface of a human-computer interaction device provided in an exemplary embodiment of this application. Figure 4 This is a schematic diagram of the human-computer interaction interface of a human-computer interaction device provided in another exemplary embodiment of this application. For example... Figure 3 and Figure 4 As shown, the human-computer interaction interface includes two working modes: Mode 1 and Mode 2.

[0037] In other implementations, the module for setting the drift assist operating mode may include at least two physical buttons, each corresponding to a different operating mode.

[0038] In some implementations, the module for setting the control intervention intensity of drift assist may include multiple virtual buttons, where each virtual button corresponds to a control intervention intensity. As an example, such as... Figure 3As shown, the human-machine interface includes four control intervention levels: 0%, 30%, 50%, and 100%. When the control intervention level is 0%, the steering assist function is not activated, and the driver manually steers the vehicle to complete the drift. When the control intervention level is 100%, the steering assist function is activated. After the driver initiates a drift, the steering system completely takes over the vehicle's steering control to ensure a successful drift; the driver does not participate in maintaining the drift. When the control intervention level is 30% or 50%, the steering assist function is activated, and the driver and steering system work together to control the vehicle to complete the drift; the steering system's control over the vehicle is 30% or 50%.

[0039] In other embodiments, the module for setting the control intervention intensity of drift assist may include multiple physical buttons, wherein each physical button corresponds to a control intervention intensity.

[0040] It should be noted that the drift assist's operating mode and control intervention intensity can be set according to actual needs. For example, the drift assist's operating mode can be "hint" or "hint + steering assist," and the control intervention intensity can be 0%, 30%, 50%, or 100%, etc. The drift assist's operating mode and control intervention intensity can be set by the developer or by the driver. The driver can change the drift assist's operating mode and control intervention intensity through the human-machine interface or through a terminal device connected to the human-machine interface.

[0041] In other implementations, the module for setting the control intervention intensity of drift assist can also be a slider or a slider block. The driver can slide the slider or slider block on the human-machine interface to set the control intervention intensity. As an example, such as... Figure 4 As shown, the module for setting the control intervention intensity of drift assist can be a slider. The driver can flexibly set the control intervention intensity by sliding the gray solid circle in the slider, where the dashed arrow indicates the sliding direction.

[0042] In some implementations, such as Figure 3 and Figure 4 As shown, the module for setting the drift assist operating mode and the module for setting the drift assist control intervention intensity can be located in the same human-machine interface. In other embodiments, the module for setting the drift assist operating mode and the module for setting the drift assist control intervention intensity can be located in different human-machine interfaces.

[0043] The drift assist module 140 can calculate the steering wheel angle target based on the information output by the center of gravity sideslip angle estimation module 120 and the positioning device 110, using the drift assist control method provided in this application embodiment, and send the calculated steering wheel angle target to the steering system 150.

[0044] The steering system 150 can receive the steering wheel angle target sent by the drift assist module 140 and control the vehicle's steering wheel to follow the steering wheel angle target to achieve drift assist control. The steering system 150 can adopt an existing electric power steering (EPS) system, an active front steering (AFS) system, or a steer-by-wire system, without specific limitations, so as not to require mechanical changes to the vehicle configuration.

[0045] Please see Figure 5 , Figure 5 This is a schematic flowchart of a drift-assisted control method provided in an embodiment of this application. This drift-assisted control method can be applied to the above-mentioned... Figure 1 The drift assist module 140 in the drift assist control system 100 shown, or as will be mentioned below Figure 12 The drift assist control device 400 shown, or as will be mentioned below Figure 13 The vehicle 500 shown. The drift assist control method may include the following steps 210 to 230.

[0046] Step 210: If the vehicle meets the drift assist control conditions, obtain the drift assist working mode and drift assist control intervention intensity determined by the driver.

[0047] The drift assist control condition is that the vehicle is on a non-public road and the drift assist function is activated.

[0048] The operating mode refers to the different drift assistance modes provided by the drift assist module to the driver. There are at least two operating modes, and the specific mode can be set according to the driver's needs. For example, the operating modes include "Prompt" and "Prompt + Steering Assist." "Prompt" means only providing relevant information about drift assistance to guide the user in completing the drift. "Prompt + Steering Assist" means providing relevant information about drift assistance while simultaneously activating the steering assist function, using the steering system to control the vehicle for drift assistance, to help the driver complete the drift. The prompt information could be, for example, the vehicle's actual sideslip angle and the steering wheel angle target in step 220.

[0049] The control intervention strength refers to the degree to which the driver allows the driver assistance module to intervene in drift control. The control intervention strength value ranges from greater than or equal to 0 to less than or equal to 1.

[0050] When the control intervention intensity is 0, it means that the steering wheel angle target of the drift assist is the same as the angle tended by the tire return torque of the pure mechanical steering system. At this time, the steering assist function is not activated, and the driver manually drives the vehicle to complete the drift.

[0051] When the control intervention strength is 1, it means that the steering wheel angle target of the drift assist is the angle that makes the vehicle maintain a steady drift through the corner. At this time, the steering assist function can be activated. After the driver enters the drift state, the steering system completely takes over the steering control of the vehicle to ensure that the vehicle successfully completes the drift. The driver does not participate in the process of maintaining the drift.

[0052] When the control intervention intensity is any value between 0 and 1, the steering wheel angle target of drift assist takes a linear value between the above two states, and the driver can gradually understand the vehicle behavior corresponding to different levels of assistance.

[0053] In some implementations, the drift assist module can acquire the vehicle's latitude and longitude information output by the positioning device. Based on this information and the electronic map inside the vehicle, it determines whether the vehicle is on a public road. Specifically, it can determine whether the vehicle's latitude and longitude information falls within a public road area marked on the electronic map. If the vehicle's latitude and longitude information falls within this area, the vehicle is determined to be on a public road. If the vehicle's latitude and longitude information does not fall within this area, the vehicle is determined to be on a non-public road.

[0054] In some implementations, the human-machine interface (HMI) can prompt the driver whether to enable drift assist, allowing the driver to choose to enable or disable it. The HMI can then send a confirmation message indicating activation of drift assist to the drift assist module, or a negative message indicating disabling drift assist, based on the driver's selection. If the drift assist module receives the confirmation message, it activates the drift assist function, which is then in an active state.

[0055] In some implementations, when the human-machine interface receives a command indicating that the driver has selected to activate drift assist, it can further output the drift assist operating mode and the drift assist control intervention level to the driver. The human-machine interface can then send the driver-selected drift assist operating mode and drift assist control intervention level to the drift assist module. The drift assist module can receive the driver-selected drift assist operating mode and drift assist control intervention level.

[0056] Step 220: Determine the target steering wheel angle based on the intensity of control intervention, wherein the target steering wheel angle is the steering wheel position that allows the vehicle to maintain a stable drift state.

[0057] The drift assist module can obtain information such as the vehicle's current actual center of gravity sideslip angle, actual front wheel steering angle, actual front axle sideslip angle, and actual rear axle lateral force from the center of gravity sideslip angle estimation module. Based on this information and the control intervention intensity, it calculates the target steering wheel angle.

[0058] For a detailed description of step 220, please refer to steps 320 to 330, which will be mentioned below.

[0059] Step 230: Based on the working mode and the target steering wheel angle, perform drift assist control on the vehicle.

[0060] For a detailed description of step 230, please refer to step 340, which will be mentioned below.

[0061] The drift assist control method provided in this application embodiment, when the vehicle meets the drift assist conditions, performs drift assist control on the vehicle according to the drift assist working mode and control intervention intensity determined by the driver, thereby ensuring that the vehicle maintains a stable drift state while meeting the drift driving needs of different drivers, so as to ensure that the vehicle successfully achieves drift.

[0062] Please see Figure 6 , Figure 6 This is a schematic flowchart of another embodiment of the drift-assisted control method provided in this application. This drift-assisted control method can be applied to the above-mentioned... Figure 1 The drift assist module 140 in the drift assist control system 100 shown, or as will be mentioned below Figure 12 The drift assist control device 400 shown, or as will be mentioned below Figure 13 The vehicle 500 shown. The drift assist control method may include the following steps 310 to 340.

[0063] Step 310: If the vehicle meets the drift assist control conditions, obtain the drift assist working mode and drift assist control intervention intensity determined by the driver.

[0064] For a detailed description of step 310, please refer to step 210 above, which will not be repeated here.

[0065] Step 320: Obtain the first steering wheel angle and the second steering wheel angle.

[0066] Specifically, when the steering wheel angle is the first steering wheel angle, the vehicle's yaw acceleration is zero; when the steering wheel angle is the second steering wheel angle, the vehicle's front axle slip angle is zero.

[0067] In some implementations, obtaining the first steering wheel angle may include the following steps: obtaining the vehicle's current actual front wheel angle, actual front axle slip angle, and target front axle slip angle; determining the first front wheel angle target based on the actual front wheel angle, actual front axle slip angle, and target front axle slip angle; and determining the first steering wheel angle based on the first front wheel angle target and a steering system model, wherein the steering system model includes the correspondence between the front wheel angle and the steering wheel angle.

[0068] In some implementations, obtaining the actual front wheel steering angle and the actual front axle sideslip angle may include the following steps: obtaining the current first vehicle state information and the second vehicle state information; inputting the obtained first vehicle state information and the second vehicle state information into the vehicle dynamics model to obtain information such as the actual center of gravity sideslip angle, the actual front wheel steering angle, the actual front axle sideslip angle, and the actual rear axle lateral force.

[0069] The first vehicle status information includes the vehicle's current steering wheel angle and speed, output by the center of gravity sideslip angle estimation module. The second vehicle status information includes the vehicle's current yaw rate and lateral acceleration, output by the positioning device.

[0070] In other embodiments, the center of gravity sideslip angle estimation module includes a vehicle dynamics model. This module can use the dynamics model to estimate information such as the actual center of gravity sideslip angle, actual front wheel steering angle, actual front axle sideslip angle, and actual rear axle lateral force, based on the first and second vehicle state information. The drift assist module can directly obtain this information from the center of gravity sideslip angle estimation module.

[0071] In some implementations, obtaining the target front axle sideslip angle may include the following steps: obtaining the road adhesion coefficient, front axle load, front axle tire lateral stiffness, and front axle lateral force target of the vehicle's front axle; and determining the target front axle sideslip angle based on the road adhesion coefficient, front axle load, front axle tire lateral stiffness, and front axle lateral force target.

[0072] In this embodiment, the coefficient of adhesion refers to the ratio of the adhesion force to the wheel's normal (perpendicular to the road surface) pressure. The coefficient of adhesion can be considered as the static friction coefficient between the tire and the road surface. The coefficient of adhesion is determined by the road surface and the tire; the larger the coefficient of adhesion, the greater the available adhesion force for the vehicle, and the less likely the vehicle is to slip.

[0073] In some implementations, the drift assist module can acquire the yaw rate and lateral acceleration output by the positioning device, and input these values ​​into a Kalman filter to obtain the road adhesion coefficients for the front and rear axles. The Kalman filter is constructed based on a vehicle dynamics model and a Dugoff tire model.

[0074] In other implementations, the Kalman filter can be incorporated into the center-of-gravity sideslip angle estimation module. This module can then use the road surface adhesion coefficients of the front and rear axles based on the yaw rate and lateral acceleration output by the positioning device. The drift assist module can directly obtain the road surface adhesion coefficients of the front and rear axles from the center-of-gravity sideslip angle estimation module.

[0075] In this embodiment, the front axle load refers to the load distribution received by the front axle of the vehicle, i.e., the load received by the front wheels. The front axle load is a fixed parameter set at the vehicle's factory and can be directly obtained from the vehicle's parameter table. This parameter table includes various performance parameters of the vehicle. In some implementations, if the front axle load is not present in the parameter table, it can be calculated using the lever principle formula based on the vehicle's center position, the number of axles, and the axle's center of gravity.

[0076] In this embodiment, tire lateral stiffness refers to the ratio of the tire's lateral force to its slip angle. Tire lateral stiffness can be expressed as k = F / a, where k is the lateral stiffness, F is the lateral force, and a is the slip angle. The front axle tire lateral stiffness is a fixed parameter set at the vehicle's factory and can be directly obtained from the vehicle's parameter table. In some embodiments, if the front axle tire lateral stiffness is not found in the parameter table, the ratio of the front wheel's lateral force to its slip angle can be calculated and used as the front axle tire lateral stiffness.

[0077] In some implementations, obtaining the front axle lateral force target may include the following steps: obtaining the actual rear axle lateral force of the vehicle, the distance between the center of gravity and the rear axle, and the distance between the center of gravity and the front axle; and determining the front axle lateral force target based on the actual rear axle lateral force, the distance between the center of gravity and the rear axle, the distance between the center of gravity and the front axle, and the actual front wheel steering angle.

[0078] The actual front wheel steering angle and actual rear axle lateral force are output from the aforementioned vehicle dynamics model. For details, please refer to the relevant sections mentioned above, and will not be repeated here.

[0079] The distances between the center of gravity and the rear axle, and between the center of gravity and the front axle, are fixed parameters set at the vehicle's factory and can be directly obtained from the vehicle's parameter table. In some implementations, if the distances between the center of gravity and the rear axle, and between the center of gravity and the front axle, are not found in the aforementioned parameter tables, they can be directly calculated. Here, the front axle refers to the bracket connecting the two front wheels, and the rear axle refers to the bracket connecting the two rear axles.

[0080] In some implementations, the target front axle lateral force can be calculated using the following expression:

[0081]

[0082] Among them, F yf，target Characterizing the front axle lateral force target, F yr δ represents the actual lateral force on the rear axle, b represents the distance between the center of gravity and the rear axle, a represents the distance between the center of gravity and the front axle, and δ represents the actual front wheel steering angle.

[0083] In some implementations, the target front axle sideslip angle can be calculated using the following expression:

[0084]

[0085]

[0086] F yf，target =-N(λ)C αf tanα f，target ;

[0087] Where, α f，target Characterizing the front axle sideslip angle of a target, μ f F represents the road adhesion coefficient of the front axle. zf Characterizing the front axle load, C αf Characterizing the lateral stiffness of the front axle tires, N(λ) and λ are process variables and have no practical significance. F yf，target Characterizes the lateral force target of the front axle.

[0088] In some implementations, the target first front wheel steering angle can be calculated using the following expression:

[0089] δ1=δ+α f -α f，target ;

[0090] Where δ1 represents the target front wheel steering angle, δ represents the actual front wheel steering angle, and α f Characterizing the actual front axle sideslip angle, α f，target Characterizes the front axle side slip angle target.

[0091] In some implementations, determining the first steering wheel angle based on the first front wheel steering angle target and the steering system model may include the following steps: Based on the first front wheel steering angle target, look up the first steering wheel angle corresponding to the first front wheel steering angle target in the front wheel steering angle-steering wheel angle mapping table of the steering system model. The front wheel steering angle-steering wheel angle mapping table includes the correspondence between front wheel steering angles and steering wheel angles, with different front wheel steering angles corresponding to different steering wheel angles. As an example, the front wheel steering angle-steering wheel angle mapping table may be as follows: Figure 7 As shown, Figure 7 The horizontal axis represents the steering wheel angle, and the vertical axis represents the front wheel angle. For example... Figure 7 As shown, the steering wheel angle and the front wheel angle are positively correlated; that is, the larger the front wheel angle, the larger the steering wheel angle.

[0092] In some implementations, obtaining the second steering wheel angle may include the following steps: determining a target second front wheel angle based on the actual front wheel angle and the actual front axle slip angle; and determining the second steering wheel angle based on the target second front wheel angle and the steering system model.

[0093] In some implementations, the target second front wheel steering angle can be calculated using the following expression:

[0094] δ2=δ+α f ;

[0095] Where δ2 represents the target front wheel steering angle of the second round, δ represents the actual front wheel steering angle, and α f Characterizes the actual front axle slip angle.

[0096] In some implementations, determining the second steering wheel angle based on the second front wheel angle target and the above-described steering system model may include the following steps: based on the second front wheel angle target, finding the second steering wheel angle corresponding to the second front wheel angle target in the above-described front wheel angle-steering wheel angle mapping table.

[0097] Step 330: Based on the first steering wheel angle, the second steering wheel angle, and the control intervention intensity, determine the third steering wheel angle and use the third steering wheel angle as the steering wheel angle target.

[0098] In some implementations, the third steering wheel angle can be calculated using the following expression:

[0099] θ3 = θ1*S + θ2*(1-S);

[0100] Wherein, θ3 represents the third steering wheel angle, θ1 represents the first steering wheel angle, θ2 represents the second steering wheel angle, and S represents the control intervention intensity, with the value of S ranging from 0 to 1.

[0101] As shown in the expression above, the third steering wheel angle is located between the first steering wheel angle and the second steering wheel angle. When the control intervention intensity is 0, the third steering wheel angle is the same as the second steering wheel angle; when the control intervention intensity is 1, the third steering wheel angle is the same as the first steering wheel angle.

[0102] Please see Figure 8 , Figure 8 This is a schematic diagram of a vehicle force analysis diagram provided in an exemplary embodiment of this application. Figure 8 The xy coordinate system in this diagram is the tire coordinate system. Here, Vf represents the velocity direction at the front axle, and α... f δ represents the actual front axle sideslip angle, δ represents the actual front wheel steering angle, and Fyf represents the actual front axle lateral force. V represents the vehicle's velocity direction, Vx represents the vehicle's velocity on the x-axis, β represents the vehicle's velocity on the y-axis, and β represents the vehicle's sideslip angle at the center of gravity. Vr represents the velocity direction at the rear axle, and α... r The actual rear axle slip angle is represented by Fyr, which represents the lateral force generated by the tires on the rear axle.

[0103] like Figure 8 As shown, the vehicle maintains a drift state while making a right turn. The driver counter-steers to the left, positioning the front wheels in the left-turn zone. Since the velocity direction Vf at the front axle is to the left of the front wheels, a rightward lateral force Fyf is generated on the front axle, and a rightward lateral force Fyr is generated on the rear axle. These two lateral forces (Fyf from the front axle and Fyr from the rear axle) cause the vehicle to experience a rightward lateral acceleration. Furthermore, the yaw moments generated by the front and rear axle lateral forces relative to the vehicle's center of gravity are equal, resulting in a state of torque equilibrium. The yaw rate remains constant, allowing the vehicle to drift through the corner in a stable state.

[0104] Please see Figure 9 , Figure 9 This is a schematic diagram of the force analysis diagram of a vehicle provided in another exemplary embodiment of this application. Figure 9 The xy coordinate system in this diagram is the tire coordinate system. Here, Vf represents the velocity direction at the front axle, and α... f δ represents the actual front axle sideslip angle, δ represents the actual front wheel steering angle, and Fyf represents the actual front axle lateral force. V represents the vehicle's velocity direction, Vx represents the vehicle's velocity on the x-axis, β represents the vehicle's velocity on the y-axis, and β represents the vehicle's center of gravity sideslip angle.

[0105] like Figure 9 As shown, when a vehicle enters a drift state, if the steering wheel is still at the 0-degree position, that is, the front wheel angle is at the δ1 position, the front axle slip angle will be very large, and the tires will be in the saturation zone of lateral force, which usually causes the vehicle to accelerate and yaw, resulting in a fishtail and loss of control.

[0106] If the front wheel steering angle is at position δ2, the lateral force generated by the front axle slip angle perfectly satisfies the vehicle's torque balance condition, and the vehicle's yaw rate can remain constant. At this point, the tire operates in the linear region of lateral force, and the magnitude of the tire lateral force can be linearly adjusted by increasing or decreasing the front wheel steering angle, thereby increasing or decreasing the yaw rate and changing the vehicle's turning radius. Therefore, the area near position δ2 is the desired front wheel steering angle position during drifting.

[0107] If the front wheel steering angle is at position δ3, the front wheel slip angle is 0 degrees, and no lateral force will be generated on the tires. Under the action of the lateral force of the rear axle tires, the yaw rate of the vehicle will decrease sharply, causing the vehicle to exit the drift state and return to stable driving.

[0108] The method provided in this application embodiment can keep the front wheel steering angle at a certain position between δ2 and δ3 (depending on the driver's choice), preventing the vehicle from entering the saturation zone of tire lateral force, thereby assisting the driver in maintaining a stable drift state and successfully completing the vehicle drift.

[0109] Step 340: Based on the working mode and the target steering wheel angle, perform drift assist control on the vehicle.

[0110] In some implementations, if the operating mode indicates that the vehicle is eligible for steering assistance (e.g., the operating mode is "caution + steering assistance"), the actual center of gravity sideslip angle of the vehicle is obtained, and a warning message is sent to the driver; drift assistance control is then applied to the vehicle based on the target steering wheel angle. The warning message includes the actual center of gravity sideslip angle and the target steering wheel angle.

[0111] The actual sideslip angle of the center of gravity is output by the vehicle dynamics model mentioned above. For details, please refer to the relevant part of step 220 above, which will not be repeated here.

[0112] In some implementations, drift assist control of a vehicle based on a target steering wheel angle may include the following steps: acquiring the steering torque applied by the driver to the steering wheel, and determining a corresponding gain based on the steering torque; using a proportional-integral-derivative (PID) control method to determine the motor torque based on the target steering wheel angle; determining a target motor torque based on the gain and the motor torque; and performing drift assist control of the vehicle based on the target motor torque.

[0113] There is a corresponding relationship between the steering torque applied by the driver to the steering wheel and its gain, forming a steering torque-gain mapping table, where different steering torques correspond to different gains. As an example, the steering torque-gain mapping table can be as follows: Figure 10 As shown, Figure 10 The horizontal axis represents steering torque, and the vertical axis represents gain. For example... Figure 10As shown, the gain ranges from 0 to 1, and there is an inverse correlation between the steering torque and the gain, that is, the greater the steering torque, the smaller the gain.

[0114] In some implementations, the steering torque applied by the driver to the steering wheel can be obtained, and the gain corresponding to the steering torque can be found in the steering torque-gain mapping table.

[0115] In some implementations, the target motor torque can be calculated using the following expression:

[0116] T sac，final =T sac *G(T h );

[0117] Among them, T sac，final Characterizing the torque of the target motor, T sac Characterizing the torque of a motor, G(T) h Characterizes gain.

[0118] By adjusting the gain, drivers can autonomously adjust the steering wheel angle at any time near the target angle for drift assist. That is, increasing the driver's steering torque reduces the steering angle control intensity of drift assist, without interfering with the driver's adjustments. For example, if the driver releases the steering wheel, drift assist will take full control of the steering wheel angle to the target position to maintain stable drifting. If the driver wants to take over the drift, they can smoothly increase or decrease the steering wheel angle, thus improving the user experience.

[0119] In some implementations, if the operating mode indicates that steering assistance is not permitted (e.g., the operating mode is "prompt"), the aforementioned prompt information is sent to the driver so that the driver can drift control the vehicle based on the prompt information. As mentioned earlier, the prompt information includes the actual center of gravity sideslip angle and the target steering wheel angle. By sending the prompt information to the driver, the driver can control the steering wheel based on the prompt information to assist in drifting and improve the success rate of manual drifting.

[0120] The drift assist control method provided in this application embodiment, when the vehicle meets the drift assist conditions, performs drift assist control on the vehicle according to the drift assist working mode and control intervention intensity determined by the driver. The driver can participate in the drift driving process. According to the different needs of the driver, the steering wheel rotation range required to maintain the drift can be prompted to the driver in real time, or the steering system's angle interface can be used to directly help the driver turn the steering wheel to the position required for drifting.

[0121] Please see Figure 11 , Figure 11This is a schematic flowchart of a drift-assisted control method provided in an exemplary embodiment of this application. This drift-assisted control method can be applied to the above-described... Figure 1 The drift assist module 140 in the drift assist control system 100 shown, or as will be mentioned below Figure 12 The drift assist control device 400 shown, or as will be mentioned below Figure 13 The vehicle shown is 500.

[0122] The positioning device outputs the second vehicle status information to the center of gravity sideslip angle estimation module. The center of gravity sideslip angle estimation module obtains the first vehicle status information from the vehicle communication network. The center of gravity sideslip angle estimation module includes a vehicle dynamics model. Based on the first and second vehicle status information, the module uses the dynamics model to estimate the actual center of gravity sideslip angle, the actual front wheel steering angle δ, and the actual front axle sideslip angle α. f And the actual rear axle lateral force F yr Information such as latitude and longitude is output by the positioning device to the drift assist module.

[0123] The human-machine interface (HMI) prompts the driver whether to activate drift assist. If the HMI receives a command indicating the driver has selected to activate drift assist, it sends a confirmation message to the drift assist module, along with the selected drift assist operating mode and the drift assist intervention level S. If the HMI receives a command indicating the driver has selected not to activate drift assist, it sends a negative message to the drift assist module indicating that drift assist is not enabled. The HMI obtains the target steering wheel angle θ3 from the drift assist module and the actual center of gravity sideslip angle from the center of gravity sideslip angle estimation module, displaying the target steering wheel angle θ3 and the actual center of gravity sideslip angle through the HMI interface.

[0124] The drift assist module determines whether the vehicle is on a non-public road based on the latitude and longitude information output by the positioning device. If it determines the vehicle is on a non-public road, it sends a command to the human-machine interface indicating whether to activate drift assist. If the drift assist module receives confirmation of activation, it activates the drift assist function, which is then in an active state. The drift assist module uses the actual front wheel steering angle δ and the actual front axle sideslip angle α... f The road adhesion coefficient μ of the front axle f Front axle load F zf Front axle tire lateral stiffness C αf Actual rear axle lateral force F yrThe distance *b* between the center of gravity and the rear axle, and the distance *a* between the center of gravity and the front axle, are used to calculate the first steering wheel angle θ1 in conjunction with the steering system model. The drift assist module calculates the actual front wheel steering angle δ and the actual front axle sideslip angle α. f The second steering wheel angle θ2 is calculated based on the steering system model. The drift assist module calculates the third steering wheel angle θ3 based on the first steering wheel angle θ1, the second steering wheel angle θ2, and the control intervention intensity S, and uses the third steering wheel angle θ3 as the target steering wheel angle θ3.

[0125] The steering system obtains the target steering wheel angle and the driver's selected operating mode from the drift assist module through its steering angle control interface. Based on the driver's selected operating mode, the steering system controls the steering wheel to turn to the target steering wheel angle position θ3 to maintain a stable drift state.

[0126] For parts not described in detail in this exemplary embodiment, please refer to the relevant parts in the foregoing embodiments, and they will not be repeated here.

[0127] Please see Figure 12 , Figure 12 This is a structural block diagram of a drift assist control device provided in an embodiment of this application. The drift assist control device 400 can be applied to the above-mentioned... Figure 1 The drift assist module 140 in application scenario 100 shown, or as will be mentioned below Figure 13 The vehicle 500 shown is described. The drift assist control device 400 includes an information acquisition module 410, a target determination module 420, and a drift control module 430. The information acquisition module 410 acquires the drift assist operating mode and the drift assist control intervention intensity determined by the driver if the vehicle meets the drift assist control conditions. The target determination module 420 determines the steering wheel angle target based on the control intervention intensity, wherein the steering wheel angle target is the steering wheel position that maintains the vehicle in a stable drift state. The drift control module 430 performs drift assist control on the vehicle based on the operating mode and the steering wheel angle target.

[0128] In some embodiments, the target determination module 420 is further configured to acquire a first steering wheel angle and a second steering wheel angle, wherein when the steering wheel angle is the first steering wheel angle, the vehicle's yaw acceleration is zero, and when the steering wheel angle is the second steering wheel angle, the vehicle's front axle sideslip angle is zero; based on the first steering wheel angle, the second steering wheel angle, and the control intervention intensity, a third steering wheel angle is determined, and the third steering wheel angle is used as the steering wheel angle target, wherein the third steering wheel angle is located between the first steering wheel angle and the second steering wheel angle.

[0129] In some embodiments, the target determination module 420 is further configured to acquire the vehicle's current actual front wheel steering angle, actual front axle slip angle, and front axle slip angle target; determine a first front wheel steering angle target based on the actual front wheel steering angle, the actual front axle slip angle, and the front axle slip angle target; and determine a first steering wheel angle based on the first front wheel steering angle target and the steering system model, wherein the steering system model includes the correspondence between the front wheel steering angle and the steering wheel angle.

[0130] In some embodiments, the target determination module 420 is further configured to acquire the road adhesion coefficient, front axle load, front axle tire lateral stiffness, and front axle lateral force target of the vehicle's front axle; and determine the front axle slip angle target based on the road adhesion coefficient, front axle load, front axle tire lateral stiffness, and front axle lateral force target.

[0131] In some embodiments, the target determination module 420 is further configured to acquire the actual rear axle lateral force of the vehicle, the distance between the center of gravity and the rear axle, and the distance between the center of gravity and the front axle; and to determine the front axle lateral force target based on the actual rear axle lateral force, the distance between the center of gravity and the rear axle, the distance between the center of gravity and the front axle, and the actual front wheel steering angle.

[0132] In some embodiments, the target determination module 420 is further configured to determine a second front wheel steering angle target based on the actual front wheel steering angle and the actual front axle sideslip angle; and to determine a second steering wheel angle based on the second front wheel steering angle target and the steering system model.

[0133] In some embodiments, the drift control module 430 is further configured to, if the operating mode indicates that the vehicle is permitted to use steering assistance, obtain the actual center of gravity sideslip angle of the vehicle, and send a prompt message to the driver, wherein the prompt message includes the actual center of gravity sideslip angle and the steering wheel angle target; and perform drift assistance control on the vehicle based on the steering wheel angle target.

[0134] In some embodiments, the drift control module 430 is further configured to acquire the steering torque applied by the driver to the steering wheel, determine a corresponding gain based on the steering torque, determine the motor torque based on the target steering wheel angle using a proportional-integral-derivative control method, determine a target motor torque based on the gain and the motor torque, and perform drift assist control on the vehicle based on the target motor torque.

[0135] In some embodiments, the drift control module 430 is further configured to send the prompt information to the driver if the operating mode indicates that the vehicle does not require steering assistance, so that the driver can drift control the vehicle according to the prompt information.

[0136] Those skilled in the art will clearly understand that the drift assist control device 400 provided in the embodiments of this application can implement the drift assist control method provided in the embodiments of this application. The specific working process of the above-mentioned device and module can be found in the process corresponding to the drift assist control method in the embodiments of this application, and will not be repeated here.

[0137] In the embodiments provided in this application, the coupling, direct coupling, or communication connection between the modules shown or discussed may be indirect coupling or communication coupling through some interfaces, devices, or modules, and may be electrical, mechanical, or other forms. The embodiments of this application do not limit this.

[0138] Furthermore, the functional modules in the embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated modules described above can be implemented in hardware or as software functional modules, and this application embodiment does not impose any restrictions on this.

[0139] Please see Figure 13 , Figure 13 This is a structural block diagram of a vehicle provided in an embodiment of this application. The vehicle 500 may include one or more of the following components: a memory 510, one or more processors 520, and one or more application programs, wherein the one or more application programs may be stored in the memory 510 and configured to, when invoked by one or more processors 520, cause one or more processors 520 to execute the drift assist control method provided in the embodiment of this application.

[0140] Vehicle 500 is equipped with the aforementioned driver assistance control system (e.g., ADAS). The drive configuration of Vehicle 500 can be rear-wheel drive, four-wheel drive, or front-wheel drive, without specific restrictions.

[0141] Processor 520 may include one or more processing cores. Processor 520 connects to various parts of the vehicle 500 via various interfaces and lines, and is used to run or execute instructions, programs, code sets, or instruction sets stored in memory 510, as well as to call and execute data stored in memory 510, performing various functions and processing data of the vehicle 500. Optionally, processor 520 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). Processor 520 may integrate one or more of a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), and a modem. The CPU primarily handles the operating system, driver interface, and applications; the GPU is responsible for rendering and drawing displayed content; and the modem handles wireless communication. It is understood that the modem may also not be integrated into processor 520, but implemented separately through a communication chip.

[0142] The memory 510 may include random access memory (RAM) or read-only memory (ROM). The memory 510 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 510 may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for implementing at least one function, instructions for implementing the various method embodiments described above, etc. The data storage area may store data created by the vehicle 500 during use.

[0143] Please see Figure 14 , Figure 14 This is a structural block diagram of a computer-readable storage medium provided in an embodiment of this application. The computer-readable storage medium 600 stores program code 610, which is configured to cause the processor to execute the drift-assisted control method provided in the embodiment of this application when called by the processor.

[0144] The computer-readable storage medium 600 may be an electronic storage device such as flash memory, electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), hard disk, or ROM. Optionally, the computer-readable storage medium 600 includes a non-volatile computer-readable storage medium (Non-TCRSM). The computer-readable storage medium 600 has storage space for program code 610 that performs any of the method steps described above. This program code 610 can be read from or written to one or more computer program products. The program code 610 may be compressed in an appropriate form.

[0145] In summary, this application provides a drift assist control method, device, vehicle, and storage medium. The method, when the vehicle meets the drift assist control conditions, acquires the drift assist operating mode and drift assist control intervention intensity determined by the driver; determines the steering wheel angle target based on the control intervention intensity; and performs drift assist control on the vehicle based on the operating mode and steering wheel angle target. This ensures that the vehicle maintains a stable drift state while meeting the drift driving needs of different drivers, thereby ensuring the vehicle successfully performs a drift.

[0146] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A drift-assisted control method, characterized in that, include: If the vehicle meets the drift assist control conditions, obtain the drift assist working mode and drift assist control intervention intensity determined by the driver; The steering wheel angle target is determined based on the control intervention intensity, wherein the steering wheel angle target is the steering wheel position that allows the vehicle to maintain a stable drift state; Based on the operating mode and the target steering wheel angle, the vehicle is subjected to drift assist control; The step of determining the target steering wheel angle based on the control intervention intensity includes: acquiring a first steering wheel angle and a second steering wheel angle, wherein when the steering wheel angle is the first steering wheel angle, the vehicle's yaw acceleration is zero, and when the steering wheel angle is the second steering wheel angle, the vehicle's front axle sideslip angle is zero; determining a third steering wheel angle based on the first steering wheel angle, the second steering wheel angle, and the control intervention intensity, and using the third steering wheel angle as the target steering wheel angle, wherein the third steering wheel angle is located between the first steering wheel angle and the second steering wheel angle; The drift assist control of the vehicle based on the operating mode and the steering wheel angle target includes: if the operating mode indicates that the vehicle is allowed to use steering assist, obtaining the actual center of gravity sideslip angle of the vehicle, and sending a prompt message to the driver, wherein the prompt message includes the actual center of gravity sideslip angle and the steering wheel angle target, and performing drift assist control of the vehicle based on the steering wheel angle target; if the operating mode indicates that the vehicle is not allowed to use steering assist, sending the prompt message to the driver so that the driver can perform drift control of the vehicle based on the prompt message.

2. The method according to claim 1, characterized in that, The process of obtaining the first steering wheel angle includes: Obtain the vehicle's current actual front wheel steering angle, actual front axle sideslip angle, and target front axle sideslip angle; The first front wheel steering angle target is determined based on the actual front wheel steering angle, the actual front axle slip angle, and the front axle slip angle target. Based on the first front wheel steering angle target and the steering system model, the first steering wheel angle is determined, wherein the steering system model includes the correspondence between the front wheel steering angle and the steering wheel angle.

3. The method according to claim 2, characterized in that, The acquisition of the front axle side slip angle target includes: Obtain the road adhesion coefficient, front axle load, front axle tire lateral stiffness, and front axle lateral force target of the vehicle's front axle; The target front axle slip angle is determined based on the road surface adhesion coefficient of the front axle, the front axle load, the front axle tire lateral stiffness, and the target front axle lateral force.

4. The method according to claim 3, characterized in that, The acquisition of the front axle lateral force target includes: The actual rear axle lateral force, the distance between the center of gravity and the rear axle, and the distance between the center of gravity and the front axle of the vehicle are obtained. The target front axle lateral force is determined based on the actual rear axle lateral force, the distance between the center of gravity and the rear axle, the distance between the center of gravity and the front axle, and the actual front wheel steering angle.

5. The method according to any one of claims 2-4, characterized in that, The steps for obtaining the second steering wheel angle include: The second front wheel steering angle target is determined based on the actual front wheel steering angle and the actual front axle slip angle. The second steering wheel angle is determined based on the second front wheel steering angle target and the steering system model.

6. The method according to claim 1, characterized in that, The drift assist control of the vehicle based on the target steering wheel angle includes: The steering torque applied by the driver to the steering wheel is obtained, and the corresponding gain is determined based on the steering torque. The proportional-integral-derivative (PI-DI) control method is used to determine the motor torque based on the target steering wheel angle. The target motor torque is determined based on the gain and the motor torque. The vehicle is drift-assisted controlled based on the target motor torque.

7. A drift-assisted control device, characterized in that, include: The information acquisition module is used to acquire the drift assist working mode and drift assist control intervention intensity determined by the driver if the vehicle meets the drift assist control conditions. The target determination module is used to determine the steering wheel angle target based on the control intervention intensity, wherein the steering wheel angle target is the steering wheel position that allows the vehicle to maintain a stable drift state; A drift control module is used to perform drift assist control on the vehicle according to the working mode and the steering wheel angle target; The step of determining the target steering wheel angle based on the control intervention intensity includes: acquiring a first steering wheel angle and a second steering wheel angle, wherein when the steering wheel angle is the first steering wheel angle, the vehicle's yaw acceleration is zero, and when the steering wheel angle is the second steering wheel angle, the vehicle's front axle sideslip angle is zero; determining a third steering wheel angle based on the first steering wheel angle, the second steering wheel angle, and the control intervention intensity, and using the third steering wheel angle as the target steering wheel angle, wherein the third steering wheel angle is located between the first steering wheel angle and the second steering wheel angle; The drift assist control of the vehicle based on the operating mode and the steering wheel angle target includes: if the operating mode indicates that the vehicle is allowed to use steering assist, obtaining the actual center of gravity sideslip angle of the vehicle, and sending a prompt message to the driver, wherein the prompt message includes the actual center of gravity sideslip angle and the steering wheel angle target, and performing drift assist control of the vehicle based on the steering wheel angle target; if the operating mode indicates that the vehicle is not allowed to use steering assist, sending the prompt message to the driver so that the driver can perform drift control of the vehicle based on the prompt message.

8. A vehicle, characterized in that, include: Memory; One or more processors; One or more applications, wherein the one or more applications are stored in the memory and configured to, when invoked by the one or more processors, cause the one or more processors to perform the method as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium contains program code that, when invoked by a processor, causes the processor to perform the method as described in any one of claims 1-6.

Images