Vehicle control method, vehicle and computer readable storage medium

Abstract

The invention provides a vehicle control method, a vehicle and a computer readable storage medium, and relates to the field of vehicle control, the method comprises the following steps: when it is judged that the vehicle slides downwards due to the action of gravity during a climbing period, if a brake pedal stroke is received, obtaining a first braking force distributed for wheels according to the brake pedal stroke, under the condition that the first braking force is larger than the wheel braking force extreme value, the first braking force is reduced to be smaller than the wheel braking force extreme value, second braking force is obtained, the service braking system is controlled to apply braking force to the wheels based on the second braking force, the slip rate of the wheels is obtained, and when the slip rate of the wheels is smaller than the minimum value of the threshold value interval, braking is conducted. And a power system and / or a parking braking system are / is controlled to conduct braking force compensation on the wheels so that the slip rate of the wheels can be within the threshold value interval. According to the method, the vehicle can be prevented from losing stability under the condition that the vehicle falls down or slips, and the stability and safety of the vehicle in a cross-country scene can be improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle control, and more specifically, to a vehicle control method, a vehicle and a computer-readable storage medium in the field of vehicle control. Background Art

[0002] With the popularity of off-road vehicles, more and more drivers like to choose to drive in complex terrain conditions, especially in mountainous areas, deserts or muddy roads. However, in these extreme environments, especially when climbing on a slope with a large slope, it is easy to fall down or slide down the slope. During the period of falling down or sliding down the slope, the vehicle is prone to instability, which brings safety hazards to the driver and passengers. Summary of the invention

[0003] The embodiments of the present application provide a vehicle control method, a vehicle and a computer-readable storage medium. The embodiments of the present application can prevent the vehicle from becoming unstable when the vehicle is going downhill or sliding down a slope, which is beneficial to improving the stability and safety of the vehicle in off-road scenarios.

[0004] In a first aspect, a vehicle control method is provided, the vehicle control method comprising: when it is determined that a preset phenomenon occurs in the vehicle during climbing, if a first brake pedal stroke is received, for each wheel, a first target braking torque allocated to the wheel is obtained according to the first brake pedal stroke; wherein the preset phenomenon is a phenomenon that the vehicle slides downward on a slope due to gravity; when the first target braking torque is greater than an extreme value of the wheel braking torque, the first target braking torque is reduced to obtain a second target braking torque corresponding to the wheel; wherein the second target braking torque is less than the extreme value of the wheel braking; controlling the service braking system to apply a braking torque to the wheel based on the second target braking torque; obtaining an actual slip rate of the wheel; and when the actual slip rate is less than a minimum value of a slip rate threshold interval, controlling the power system and / or the parking brake system to perform braking torque compensation on the wheel so that the actual slip rate is within the slip rate threshold interval.

[0005] In one possible implementation, when the actual slip rate is less than the minimum value of the slip rate threshold interval, controlling the power system and / or the parking brake system to perform braking torque compensation on the wheel includes: when the actual slip rate is less than the minimum value of the slip rate threshold interval, obtaining a second brake pedal stroke and an actual braking torque applied to the wheel by the service brake system; if the second brake pedal stroke is greater than the first brake pedal stroke and the actual braking torque is less than the wheel braking torque extreme value, controlling the power system and / or the parking brake system to perform braking torque compensation on the wheel.

[0006] In a possible implementation, the controlling of the power system and / or the parking brake system to compensate the braking torque of the wheel includes at least one of the following: controlling the target drive motor in the power system to output a first stall torque, using the first stall torque as the compensation braking torque, and applying it to the wheel; controlling the parking brake system to output a first parking braking torque, using the first parking braking torque as the compensation braking torque, and applying it to the wheel; controlling the target drive motor in the power system to output a second stall torque, controlling the target drive motor in the power system to output a second stall torque, using the sum of the second stall torque and the second parking braking torque as the compensation braking torque, and applying it to the wheel; wherein the target drive motor is a drive motor that drives the wheel, the first stall torque and the second stall torque are both opposite to the direction of the drive torque output by the target drive motor, and the compensation braking torque is the difference between the extreme value of the wheel braking torque and the actual braking torque.

[0007] In one possible implementation, the vehicle control method also includes: when the target drive motor satisfies a first condition, executing the step of controlling the target drive motor in the power system to output a first stall torque; wherein the first condition includes the ambient temperature being less than a first temperature threshold, the motor temperature being less than a second temperature threshold, the battery temperature of the power battery being less than a third temperature threshold, the remaining power of the power battery being greater than a power threshold, and the motor output power being greater than a power threshold.

[0008] In one possible implementation, controlling the target drive motor in the power system to output the first stall torque includes: controlling the target drive motor to output the first stall torque according to a time-torque curve having a first slope; controlling the parking brake system to output the first parking braking torque includes: controlling the parking brake system to output the first parking braking torque according to a time-torque curve having a second slope.

[0009] In one possible implementation, the vehicle control method further includes: determining a first wheel vertical load of the wheel based on a change in suspension height corresponding to the wheel and an actual slope of the road on which the vehicle is located; and obtaining an extreme value of the wheel braking torque based on a product of the first wheel vertical load and the actual slip rate.

[0010] In a possible implementation, obtaining the actual slip rate of the wheel includes: obtaining a road image of the road on which the vehicle is located; determining a matching degree between the road image and a preset road image; and determining the actual slip rate of the wheel according to the matching degree.

[0011] In a possible implementation, determining the actual slip rate of the wheel based on the matching degree includes: if the matching degree is greater than a matching degree threshold, obtaining the actual vehicle speed and the linear speed of the wheel; and determining the actual slip rate of the wheel based on the actual vehicle speed and the linear speed.

[0012] In a possible implementation, determining the actual slip rate of the wheel according to the matching degree includes: if the matching degree is less than or equal to a matching degree threshold, determining the second wheel vertical load of the wheel according to the suspension parameters of the vehicle suspension; wherein the suspension parameters include at least one of suspension deformation, suspension stiffness and damping coefficient; determining the wheel longitudinal load of the wheel according to the first target braking torque and the target torque issued by the power system; wherein the target torque is a driving torque or a recovery torque; determining a road adhesion coefficient according to the ratio of the wheel longitudinal load to the second wheel vertical load; wherein the road adhesion coefficient includes a plurality of adhesion coefficient values; determining the derivative of the road adhesion coefficient with respect to the slip rate during the slipping process of the wheel to obtain a plurality of derivative values; determining the adhesion coefficient value corresponding to the target derivative value as the actual slip rate of the wheel; wherein the target derivative value is a derivative value among the plurality of derivative values ​​whose difference with 0 is less than a preset difference.

[0013] In one possible implementation, determining the second wheel vertical load of the wheel based on the suspension parameters of the vehicle suspension includes: determining the load transfer amount of the wheel based on the suspension deformation, the suspension stiffness and the damping coefficient; determining the unsprung mass transfer amount based on the load transfer amount; obtaining the sprung load based on the suspension deformation; and obtaining the second wheel vertical load based on the unsprung mass, the unsprung mass transfer amount and the sprung load.

[0014] In one possible implementation, after the power system and / or the parking brake system are controlled to compensate the braking torque of the wheels, the vehicle control method further includes: in response to a reset signal of the brake pedal, controlling the power system and / or the parking brake system according to a gradient descent strategy to reduce the compensatory braking torque applied to the wheels.

[0015] In a possible implementation, after obtaining the actual slip rate of the wheel, the vehicle control method further includes: prohibiting controlling the power system and the parking brake system to perform braking torque compensation on the wheel when the actual slip rates of the wheels are all greater than a maximum value of the slip rate threshold interval.

[0016] In one possible implementation, after the control service braking system applies a braking torque to the wheel based on the second target braking torque, the vehicle control method further includes: limiting steering wheel rotation when a second condition is met; wherein the second condition includes at least one of the longitudinal acceleration of the vehicle being less than an acceleration threshold, the yaw angle being less than an angle threshold, the steering wheel rotation speed being greater than a rotation speed threshold, and the absence of obstacles in the rear environment of the vehicle.

[0017] In one possible implementation, the vehicle control method further includes: upon receiving an activation command for an off-road assist function of the vehicle, obtaining an actual slope of the road on which the vehicle is located; if the actual slope is greater than a slope threshold and the driving direction of the vehicle is the same as the slope direction of the road, determining whether the preset phenomenon occurs during climbing of the vehicle.

[0018] In one possible implementation, obtaining the actual slope of the road on which the vehicle is located includes: determining a first slope of the road based on the longitudinal acceleration of the vehicle; obtaining a second slope of the road identified by the intelligent driving system of the vehicle; if a deviation value between the first slope and the second slope is less than or equal to a deviation threshold, determining the first slope or the second slope as the actual slope; if the deviation value is greater than the deviation threshold, continuously obtaining multiple longitudinal accelerations within a preset time length; determining multiple third slopes of the road based on the multiple longitudinal accelerations, and determining an average value of the multiple third slopes as the actual slope.

[0019] In a second aspect, a vehicle control device is provided, the vehicle control device comprising:

[0020] a first acquisition module, configured to, when it is determined that a preset phenomenon occurs during the climbing of the vehicle, acquire, for each wheel, a first target braking torque allocated to the wheel according to the first brake pedal stroke if a first brake pedal stroke is received; wherein the preset phenomenon is a phenomenon that the vehicle slides downward on the slope due to gravity;

[0021] a torque adjustment module, configured to reduce the first target braking torque to obtain a second target braking torque corresponding to the wheel when the first target braking torque is greater than the wheel braking torque extreme value; wherein the second target braking torque is less than the wheel braking extreme value;

[0022] a braking control module, configured to control a service braking system to apply a braking torque to the wheel based on the second target braking torque;

[0023] A second acquisition module, used to acquire an actual slip rate of the wheel;

[0024] The braking compensation module is used to control the power system and / or the parking brake system to perform braking torque compensation on the wheel when the actual slip rate is less than the minimum value of the slip rate threshold range, so that the actual slip rate is within the slip rate threshold range.

[0025] In a third aspect, a vehicle is provided, comprising a memory and a processor. The memory is used to store executable program code, and the processor is used to call and run the executable program code from the memory, so that the vehicle executes the vehicle control method in the first aspect or any possible implementation of the first aspect.

[0026] In a fourth aspect, a computer program product is provided, which includes: a computer program code, which, when executed on a computer, enables the computer to execute the vehicle control method in the above-mentioned first aspect or any possible implementation of the first aspect.

[0027] In a fifth aspect, a computer-readable storage medium is provided, which stores a computer program code. When the computer program code runs on a computer, the computer executes the vehicle control method in the above-mentioned first aspect or any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic flow chart of a vehicle control method provided in an embodiment of the present application is shown;

[0029] Figure 2 A schematic diagram showing a vehicle sliding down a slope during climbing;

[0030] Figure 3 A schematic diagram of a torque curve is shown;

[0031] Figure 4 A schematic structural diagram of a vehicle control device provided in an embodiment of the present application is shown;

[0032] Figure 5 A schematic structural diagram of a vehicle provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0033] The technical solution in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0034] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0035] With the popularity of off-road vehicles, more and more drivers like to choose to drive in complex terrain conditions, especially in mountainous areas, deserts or muddy roads. However, in these extreme environments, especially when climbing a slope with a large slope, it is easy to reverse or slide down the slope. For example, during the process of the vehicle reversing or sliding down the slope, due to the problem of axle load transfer, the normal pressure of the front axle tire will be greatly reduced, and the front axle will be very likely to brake and lock; and due to the problem of the vehicle's driving direction (the vehicle is driving down the slope), the actual front axle of the vehicle is equivalent to the actual driving rear axle. Once the front axle is locked, the vehicle will lose its steering ability at the same time and will have a tailspin, that is, the vehicle is prone to instability during reversing or sliding down the slope, which poses a safety hazard to the driver and passengers.

[0036] Based on the above problems, the embodiments of the present application provide a vehicle control method, a vehicle and a computer-readable storage medium. The embodiments of the present application can dynamically adjust the braking torque of each wheel when the vehicle slides down the slope during climbing by intelligently controlling the braking torque to ensure that the wheel will not lock and maintain an appropriate slip rate. This strategy not only improves the stability and safety of the vehicle on the slope, but also optimizes the braking force distribution to ensure that the vehicle can decelerate smoothly. By real-time monitoring of the actual slip rate of the wheel and compensating for it, the braking effect can be further improved to ensure the safety and driving experience of the vehicle, that is, when the vehicle reverses or slides down the slope, the vehicle is prevented from becoming unstable, which is conducive to improving the stability and safety of the vehicle in off-road scenarios.

[0037] The following is an embodiment of a vehicle control method provided in this application specification.

[0038] Figure 1 A schematic flow chart of a vehicle control method provided by an embodiment of the present application is shown, such as Figure 1As shown, the vehicle control method provided in the embodiment of the present application is applied to the central control unit of the vehicle, and the vehicle includes an intelligent driving system, a suspension system, a steering system, a braking system, a power system, etc. The intelligent driving system includes a radar system, a visual system, etc. The braking system includes a service braking system and a parking braking system, and the power system includes an engine and a drive motor for driving the wheels. If there are two drive motors, one of the drive motors drives the front wheels and the other drive motor drives the rear wheels; if there are four drive motors, each drive motor drives one wheel. The parking brake system and the drive motors in the power system can both serve as backups for the parking brake system. Wheel braking control can also be achieved through the parking brake system and the drive motors. Wheel braking can be achieved by controlling the clamping of the parking caliper in the parking brake system. Wheel braking can be achieved by controlling the drive motor to output a torque in the opposite direction of the driving torque.

[0039] The above vehicle control method includes the following schemes:

[0040] S110: When it is determined that a preset phenomenon occurs in the vehicle during climbing, if a first brake pedal stroke is received, for each wheel, a first target braking torque allocated to the wheel is obtained according to the first brake pedal stroke.

[0041] In an exemplary embodiment, the preset phenomenon is a phenomenon in which a vehicle slides downward on a slope due to gravity, for example, the preset phenomenon is specifically a reverse slope or a slipping slope. Figure 2 As shown, Figure 2 The schematic diagram shows a vehicle sliding down a slope while climbing a slope, where P represents the slope, C represents the vehicle, T represents the front of the vehicle, B represents the rear of the vehicle, and the arrow represents the sliding direction of the vehicle (which is also the driving direction of the vehicle, i.e., the sliding direction).

[0042] During the climbing of the vehicle, if a preset phenomenon is detected in the vehicle and a brake pedal signal is received, it means that the driver controls the vehicle to brake, and a first brake pedal stroke is obtained through the brake pedal signal. For each wheel Wi, a preset braking torque corresponding to the first brake pedal stroke is obtained to obtain a first target braking torque allocated to the wheel Wi.

[0043] S120: When the first target braking torque is greater than the extreme value of the wheel braking torque, the first target braking torque is reduced to obtain a second target braking torque corresponding to the wheel.

[0044] Since the vehicle is in a nose-up position on the slope, and the vehicle begins to slide down the slope. In this case, the center of gravity of the vehicle changes significantly, resulting in uneven load distribution on the front and rear axles. Due to the component of gravity acting along the slope, the center of gravity of the vehicle moves forward, and the vertical load on the front axle decreases, which means that the friction between the front wheels and the road surface is weakened, and the wheel braking limit of the front axle is also reduced. Conversely, the vertical load on the rear axle increases because more weight is transferred to the rear axle. This increases the friction between the rear wheels and the road surface, and the braking force limit of the rear axle is relatively high.

[0045] The wheel braking torque extreme value can also be understood as the maximum braking torque that the wheel can withstand. One way to determine the wheel braking torque extreme value is: when the parameters of the suspension system can be obtained normally (the suspension system is in a normal state), it is calculated through the suspension height change corresponding to the wheel during the operation of the vehicle, the actual slope of the road on which the vehicle is located, and other parameters. Another way to determine the wheel braking torque extreme value is: when the parameters of the suspension system cannot be obtained (the suspension system is in an abnormal state), when the slip rate of the wheel is greater than the maximum value of the slip rate threshold interval, the braking torque applied to the wheel detected is taken as the wheel braking torque extreme value. It can also be understood that after the wheel is braked and the vehicle loses stability, the braking torque applied to the wheel detected is taken as the wheel braking torque extreme value.

[0046] After obtaining the first target braking torque assigned to wheel Wi, if it is determined that the first target braking torque assigned to wheel Wi is greater than the wheel braking torque extreme value corresponding to wheel Wi, it means that the first target braking force assigned to wheel Wi exceeds the actual friction force limit of wheel Wi, which may cause wheel Wi to lock. In order to avoid this situation, the central control unit will reduce the first target braking torque assigned to wheel Wi to a safe range to ensure that it does not exceed the wheel braking torque extreme value corresponding to wheel Wi, so as to prevent wheel Wi from locking, maintain the stability and controllability of the vehicle, and ensure that the vehicle can decelerate safely.

[0047] For the front wheels, the first target braking torque assigned to the front wheels is reduced to obtain the second target braking torque corresponding to the front wheels, and the second target braking torque corresponding to the front wheels is less than the wheel braking extreme value corresponding to the front wheels. For the rear wheels, the reduced portion of the first target braking torque assigned to the front wheels is transferred to the rear wheels, and the sum of the reduced portion and the wheel braking extreme value corresponding to the rear wheels is used as the new wheel braking extreme value corresponding to the rear wheels, and then based on the new wheel braking extreme value corresponding to the rear wheels, the first target braking torque assigned to the rear wheels is reduced to obtain the second target braking torque corresponding to the rear wheels, and the second target braking torque corresponding to the rear wheels is less than the new wheel braking extreme value corresponding to the rear wheels, so that the second target braking torque corresponding to the wheel Wi can be obtained.

[0048] S130: Controlling the service braking system to apply a braking torque to the wheels based on the second target braking torque.

[0049] The second target braking torque corresponding to the wheel Wi is obtained, and the service brake system is controlled to apply a braking torque to the wheel Wi based on the second target braking torque corresponding to the wheel Wi, so as to control the deceleration of the wheel Wi, thereby performing the deceleration control of the whole vehicle. Since the second target braking torque corresponding to the wheel Wi is smaller than the extreme value of the wheel braking torque corresponding to the wheel Wi, the braking torque is applied to the wheel Wi according to the second target braking torque corresponding to the wheel Wi, so as to ensure that the wheel Wi will not lock during the period when the service brake system controls the braking of the wheel Wi.

[0050] S140: Acquire the actual slip rate of the wheel.

[0051] After controlling the service brake system to apply a braking torque to the wheel Wi based on the second target braking torque corresponding to the wheel Wi, the actual slip rate of the wheel Wi is obtained. The slip rate refers to the difference between the actual linear velocity of the wheel and its theoretical rolling velocity, reflecting the degree of slip of the wheel relative to the road surface.

[0052] S150: When the actual slip ratio is less than a minimum value of the slip ratio threshold range, control the power system and / or the parking brake system to perform braking torque compensation on the wheels so that the actual slip ratio is within the slip ratio threshold range.

[0053] The slip rate threshold interval is determined based on the friction characteristic curve of the tire, for example, the slip rate threshold interval = [10%, 20%]. Within the slip rate threshold interval, the tire can provide the maximum friction force to ensure the stability of the vehicle and the best braking effect. If the actual slip rate of wheel Wi is less than the minimum value of the slip rate threshold interval, it means that the slip rate of wheel Wi is too low, and it is considered that the braking torque applied to wheel Wi by the service brake system is insufficient, which may result in poor vehicle deceleration effect. At this time, the power system and / or parking brake system is introduced to compensate for the braking torque of wheel Wi by controlling the power system and / or parking brake system, so that the actual slip rate of wheel Wi is restored to the slip rate threshold interval.

[0054] The embodiment of the present application adopts a technical solution that when it is determined that the vehicle slides downward due to gravity during climbing, if a first brake pedal stroke is received, for each wheel, a first target braking torque allocated to each wheel is obtained according to the first brake pedal stroke; when the first target braking torque allocated to each wheel is greater than the wheel braking torque extreme value, the first target braking torque allocated to each wheel is reduced to obtain a second target braking torque corresponding to each wheel, and the second target braking torque corresponding to each wheel is less than the wheel braking extreme value corresponding to each wheel; the service braking system is controlled to apply a braking torque to each wheel based on the second target braking torque corresponding to each wheel, and an actual slip rate of each wheel is obtained; when the actual slip rate of each wheel is less than the minimum value of a slip rate threshold interval, the power system and / or the parking brake system is controlled to perform braking torque compensation on each wheel so that the actual slip rate of each wheel is within the slip rate threshold interval. This can prevent the vehicle from becoming unstable when the vehicle reverses or slides down a slope, and is beneficial to improving the stability and safety of the vehicle in off-road scenarios. By reducing the target braking torque assigned to the wheel to below the wheel's braking torque limit, it is ensured that the wheel will not exceed its friction limit and lock, which not only improves the stability of the vehicle but also avoids the risk of loss of control due to wheel locking. By monitoring the actual slip rate of the wheel in real time and performing braking force compensation through the power system and / or parking brake system when the slip rate is too low, it is ensured that the wheel slip rate is always within the slip rate threshold range, which not only improves the braking effect but also ensures the stability and controllability of the vehicle.

[0055] In a possible implementation, when the actual slip rate is less than the minimum value of the slip rate threshold range, controlling the power system and / or the parking brake system to perform braking torque compensation on the wheels includes the following steps:

[0056] When the actual slip rate is less than a minimum value of the slip rate threshold interval, obtaining a second brake pedal stroke and an actual braking torque applied to the wheel by the service brake system;

[0057] If the second brake pedal travel is greater than the first brake pedal travel and the actual braking torque is less than the wheel braking torque limit, the power system and / or the parking brake system is controlled to perform braking torque compensation on the wheels.

[0058] When the actual slip rate of wheel Wi is less than the minimum value of the slip rate threshold interval, the brake pedal signal is continuously obtained, and the second brake pedal stroke is obtained by the continuously obtained brake pedal signal. If the second brake pedal stroke is greater than the first brake pedal stroke, it means that the driver finds that the deceleration effect of the vehicle is still not ideal, and continues to step on the brake pedal to increase the braking force, that is, the driver has the intention to further control the vehicle to brake. Then, it is determined whether the actual braking torque applied by the service braking system to wheel Wi is less than the maximum braking torque that wheel Wi can withstand. If the actual braking torque applied by the service braking system to wheel Wi is less than the maximum braking torque that wheel Wi can withstand, The maximum braking torque received indicates that the service braking system's ability to continuously increase pressure is insufficient, and the braking torque applied to wheel Wi still has room for improvement without causing wheel Wi to lock. Simply applying braking torque to wheel Wi through the service braking system cannot make the actual slip rate of wheel Wi within the slip rate threshold range. Therefore, the power system and / or parking brake system is controlled to perform additional braking torque compensation on wheel Wi. This can increase the braking torque of wheel Wi and restore the actual slip rate of wheel Wi to within the slip rate threshold range, thereby compensating for the problem of insufficient braking torque of the service braking system and ensuring that the vehicle can effectively decelerate and maintain stability.

[0059] In a possible implementation, the controlling the power system and / or the parking brake system to perform braking torque compensation on the wheels includes at least one of the following:

[0060] Controlling a target drive motor in a power system to output a first stall torque, using the first stall torque as a compensating braking torque, and applying the first stall torque to a wheel;

[0061] Controlling the parking brake system to output a first parking braking torque, using the first parking braking torque as a compensation braking torque, and applying the first parking braking torque to the wheels;

[0062] Controlling a target drive motor in the power system to output a second stall torque, controlling a target drive motor in the power system to output a second stall torque, taking a sum of the second stall torque and a second parking braking torque as a compensation braking torque, and applying it to the wheels;

[0063] Among them, the target drive motor is the drive motor that drives the wheel Wi in the power system, the first stall torque and the second stall torque are opposite to the direction of the drive torque output by the target drive motor, and the compensation braking torque is the difference between the extreme value of the wheel braking torque of the wheel Wi and the actual braking torque of the wheel Wi, that is, the compensation braking torque = the extreme value of the wheel braking torque - the actual braking torque.

[0064] When the braking torque of the wheel Wi is compensated only by the power system, the compensation braking torque is used as the target value of the torque output by the target drive motor, and the stall torque output by the target drive motor is controlled to gradually reach the compensation braking torque.

[0065] When the braking torque of the wheel Wi is compensated only by the parking brake system, the compensation braking torque is used as the target value of the parking braking torque output by the parking brake system, and the parking braking torque output by the parking brake system is controlled to gradually reach the compensation braking torque.

[0066] For the braking torque compensation of the wheel Wi through the power system and the parking brake system, the compensation braking torque is divided into two parts, the first part is the second stall torque, and the second part is the second parking braking torque. The second stall torque and the second parking braking torque may be the same or different. The second stall torque is used as the target value of the torque output by the target drive motor, and the stall torque output by the target drive motor is controlled to gradually reach the second stall torque; the second parking braking torque is used as the target value of the parking braking torque output by the parking brake system, and the parking braking torque output by the parking brake system is controlled to gradually reach the second parking braking torque.

[0067] In a possible implementation, the vehicle control method further includes the following steps:

[0068] When the target drive motor satisfies a first condition, a step of controlling the target drive motor in the power system to output a first stall torque is executed; wherein the first condition includes the ambient temperature being less than a first temperature threshold, the motor temperature being less than a second temperature threshold, the battery temperature of the power battery being less than a third temperature threshold, the remaining power of the power battery being greater than a power threshold, and the motor output power being greater than a power threshold.

[0069] The ambient temperature is less than the first temperature threshold, indicating that the external ambient temperature will not be too high, avoiding the target drive motor and power battery from working in a high temperature environment to prevent overheating risks. The motor temperature is less than the second temperature threshold, indicating that the temperature of the target drive motor itself is within a safe range and the target drive motor can output torque normally. The battery temperature of the power battery is less than the third temperature threshold, indicating that the battery temperature of the power battery is within a safe range, avoiding the power battery from supplying power to the target drive motor when working at high temperatures, thereby causing safety accidents. The remaining power of the power battery is greater than the power threshold, indicating that the power battery has sufficient remaining power to supply power to the target drive motor to ensure that the target drive motor can continuously output stall torque. The motor output power is greater than the power threshold, indicating that the torque value of the stall torque output by the target drive motor can fully reach the torque value of the first stall torque.

[0070] Determining that the target drive motor satisfies the first condition indicates that the power system can work normally, and it is safe to compensate the wheel Wi with the power system for the braking torque, or the power system can completely make up for the problem of insufficient braking torque of the service brake system. Therefore, when the target drive motor satisfies the first condition, executing the step of controlling the target drive motor in the power system to output the first stall torque not only improves the safety of the target drive motor outputting the first stall torque, but also improves the reliability of the target drive motor outputting the first stall torque.

[0071] Before performing braking torque compensation on wheel Wi or during performing braking torque compensation on wheel Wi, if the target drive motor does not satisfy any one of the first conditions, the power system will not be used to compensate for the braking torque of wheel Wi; if the target drive motor does not satisfy the first condition that the remaining power of the power battery is greater than the power threshold, the engine is started to charge the power battery, and after charging, if the first condition is still not satisfied that the remaining power of the power battery is greater than the power threshold, the power system will not be used to compensate for the braking torque of wheel Wi, and the parking brake system will be used to compensate for the braking torque of wheel Wi.

[0072] In a possible implementation, controlling the target drive motor in the power system to output the first stall torque includes the following steps:

[0073] The target drive motor is controlled to output a first stall torque according to a time-torque curve having a first slope.

[0074] like Figure 3 As shown, Figure 3 A schematic diagram of a torque curve is shown, where Q1 represents a time-torque curve of a first slope k1, T represents time, and F1 represents a stall torque. In the process of using a power system to compensate the braking torque of the wheel Wi, by controlling the target drive motor to gradually increase the output stall torque according to Q1 until the first stall torque is reached, it is possible to avoid the target drive motor suddenly outputting an excessive stall torque, which is beneficial to reducing the impact on the vehicle and ensuring the stability of the vehicle.

[0075] The above-mentioned controlling the parking brake system to output the first parking brake torque comprises the following steps:

[0076] The parking brake system is controlled to output a first parking brake torque according to a time-torque curve having a second slope.

[0077] like Figure 3As shown, Q2 represents the time-torque curve of the second slope k2, F2 represents the parking braking torque, and in the process of using the parking brake system to compensate the braking torque of the wheel Wi, by controlling the parking brake system to gradually increase the output parking braking torque according to Q2 until the first parking braking torque is reached, it can avoid the parking brake system suddenly outputting too large a parking braking torque, which is beneficial to reducing the impact on the vehicle and ensuring the stability of the vehicle. Among them, k1 and k2 can be the same or different.

[0078] In a possible implementation, the vehicle control method further includes the following steps:

[0079] The maximum braking torque that the wheel Wi can withstand is calculated. The calculation process of the maximum braking torque that the wheel Wi can withstand includes:

[0080] Determine a first wheel vertical load of wheel Wi according to a change in suspension height corresponding to wheel Wi and an actual slope of a road on which the vehicle is located;

[0081] The maximum braking torque that the wheel Wi can withstand is obtained according to the product of the first wheel vertical load and the actual slip rate.

[0082] After obtaining the suspension height change corresponding to wheel Wi and the actual slope of the road on which the vehicle is located, the preset wheel vertical load corresponding to the suspension height change corresponding to wheel Wi and the actual slope of the road on which the vehicle is located is obtained to obtain the first wheel vertical load of wheel Wi, and then the maximum braking torque that wheel Wi can withstand is obtained through the first wheel vertical load of wheel Wi and the actual slip rate of wheel Wi, that is, the maximum braking torque that wheel Wi can withstand = the first wheel vertical load of wheel Wi × the actual slip rate of wheel Wi.

[0083] In a possible implementation, the above-mentioned obtaining of the actual slip rate of the wheel includes the following steps:

[0084] Acquire a road image of a road on which the vehicle is located;

[0085] Determining a degree of match between the road image and a preset road image;

[0086] The actual slip rate of the wheel is determined based on the matching degree.

[0087] The visual system is controlled to capture a road image of the road on which the vehicle is located, and the similarity between the road surface features in the road image and the road surface features in the preset road image is calculated, and the matching degree between the road image and the preset road image is represented by the similarity, and then the size relationship between the matching degree and the matching degree threshold is compared, and a target strategy for calculating the actual slip rate of the wheel Wi is determined from the first calculation strategy and the second calculation strategy, and then the target strategy is used to calculate the actual slip rate of the wheel Wi. Among them, the first calculation strategy is to calculate the slip rate based on the vehicle speed and the linear speed of the wheel, and the first calculation strategy is to calculate the slip rate based on the suspension parameters of the suspension system.

[0088] In a possible implementation, determining the actual slip rate of the wheel according to the matching degree includes the following steps:

[0089] If the matching degree is greater than the matching degree threshold, the actual vehicle speed and the linear speed of the wheels are obtained;

[0090] The actual slip rate of the wheel is determined based on the actual vehicle speed and linear speed.

[0091] If it is determined that the matching degree is greater than the matching degree threshold, it means that the road surface of the slope where the vehicle is located is flat and the road surface uniformity is good. The first calculation strategy is determined as the target strategy, and the first calculation strategy is used to calculate the actual slip rate of the wheel Wi, that is:

[0092] Actual slip ratio = [(actual vehicle speed - linear speed of wheel) / actual vehicle speed] × 100%.

[0093] In a possible implementation, determining the actual slip rate of the wheel according to the matching degree includes the following steps:

[0094] Determining the actual slip rate of each wheel includes:

[0095] If the matching degree is less than or equal to the matching degree threshold, determining a second wheel vertical load of the wheel according to a suspension parameter of the vehicle suspension;

[0096] determining a wheel longitudinal load of the wheel according to the first target braking torque and the target torque generated by the powertrain; wherein the target torque is a driving torque or a recovery torque;

[0097] Determining a road adhesion coefficient according to a ratio of the wheel longitudinal load to the second wheel vertical load; wherein the road adhesion coefficient includes a plurality of adhesion coefficient values;

[0098] Determine the derivative of the road adhesion coefficient to the slip rate during the wheel slip process to obtain a plurality of derivative values;

[0099] The adhesion coefficient value corresponding to the target derivative value is determined as the actual slip rate of the wheel.

[0100] The suspension parameters include at least one of the suspension deformation, suspension stiffness and damping coefficient. If it is determined that the matching degree is less than or equal to the matching degree threshold, it means that the road surface of the ramp where the vehicle is located is uneven, the road surface uniformity is poor, and the actual slip rate of the wheel Wi cannot be calculated based on the first calculation strategy, then the second calculation strategy is determined as the target strategy, and the actual slip rate of the wheel Wi is estimated using the second calculation strategy.

[0101] The second calculation strategy is used to estimate the actual slip rate of wheel Wi, including: calculating the second wheel vertical load corresponding to wheel Wi through the suspension parameters corresponding to wheel Wi, and then calculating the wheel longitudinal load of wheel Wi through the first target braking torque corresponding to wheel Wi, the target torque issued by the power system (target torque issued by the power system) and the slope information of the road on which the vehicle is located, and obtaining the road adhesion coefficient μ through the second wheel vertical load corresponding to wheel Wi and the wheel longitudinal load, that is:

[0102] Road adhesion coefficient μ = wheel longitudinal load / second wheel vertical load.

[0103] Since the vehicle is in the process of sliding down, the calculated road adhesion coefficient μ includes multiple adhesion coefficient values, and then the derivative of the road adhesion coefficient μ to the slip rate s of the wheel Wi during the sliding process, that is, dμ / ds, is obtained to obtain multiple derivative values, each derivative value corresponding to an adhesion coefficient value. A target derivative value is obtained from the multiple derivative values, and the target derivative value is the derivative value whose difference with 0 is less than the preset difference among the multiple derivative values, and is also the derivative value closest to the 0 point. The adhesion coefficient value corresponding to the target derivative value is determined as the actual slip rate of the wheel Wi, thereby realizing the estimation of the actual slip rate of the wheel Wi.

[0104] The matching degree between the road image and the preset road image enables calculation of the wheel slip rate when the road surface of the vehicle is a flat road surface and an uneven road surface, which is beneficial to improving the flexibility of wheel slip rate calculation.

[0105] In a possible implementation, the determining the second wheel vertical load of the wheel according to the suspension parameters of the vehicle suspension comprises the following steps:

[0106] Determine the load transfer of the wheel based on the suspension deformation, suspension stiffness and damping coefficient;

[0107] Determine the unsprung mass transfer amount based on the load transfer amount;

[0108] The sprung load is obtained according to the suspension deformation;

[0109] The second wheel vertical load is obtained according to the unsprung mass, the unsprung mass transfer and the sprung load.

[0110] The preset load transfer amount corresponding to the suspension deformation, suspension stiffness and damping coefficient is obtained to obtain the load transfer amount of the wheel Wi, and the unsprung mass transfer amount is estimated by the load transfer amount of the wheel Wi. In practical applications, the transfer amount of the sprung mass and the unsprung mass is not exactly the same. In order to simplify the calculation, it can be roughly assumed that the sprung mass transfer percentage is the same as the unsprung mass transfer percentage. In other words, it is assumed that the unsprung mass is transferred in the same proportion as the sprung mass is transferred. This approximate method is reasonable in most cases, especially when the vehicle structure is relatively symmetrical.

[0111] The preset load corresponding to the suspension deformation is obtained to obtain the sprung load, and the second wheel vertical load of the wheel Wi is obtained according to the unsprung mass, the unsprung mass transfer and the sprung load, that is, the second wheel vertical load = unsprung mass + sprung load + unsprung mass transfer.

[0112] In a possible implementation, after the above-mentioned control power system and / or parking brake system performs braking torque compensation on the wheels, the above-mentioned vehicle control method further includes the following steps:

[0113] In response to the reset signal of the brake pedal, the power system and / or the parking brake system is controlled according to the gradient descent strategy to reduce the compensating braking torque applied to the wheels.

[0114] If a reset signal of the brake pedal is detected, it means that the driver has released the brake pedal, that is, the driver no longer controls the vehicle braking. It also means that the driver may think that the vehicle is about to reverse onto a flat road, so he releases the brake pedal. In order to avoid the compensation braking torque being withdrawn too quickly, causing the vehicle to reverse too quickly, the power system and / or the parking brake system is controlled according to the gradient descent strategy to reduce the compensation braking torque applied to the wheels, that is, the compensation braking torque applied to the wheels by the power system and / or the parking brake system is gradually reduced according to a certain gradient descent value until the compensation braking torque is reduced to 0, thereby ensuring the stability of the vehicle during the withdrawal of the compensation braking torque, allowing the vehicle to make a smooth transition after releasing the brake pedal, thereby improving driving safety.

[0115] In a possible implementation, after obtaining the actual slip rate of the wheel, the vehicle control method further includes the following steps:

[0116] When the actual slip rates of the wheels are all greater than the maximum value of the slip rate threshold range, it is prohibited to control the power system and the parking brake system to perform braking torque compensation on the wheels.

[0117] If the actual slip rate of wheel Wi is greater than the maximum value of the slip rate threshold range, it means that the slip rate of wheel Wi is too high, and it is considered that the braking torque applied to wheel Wi by the service brake system is sufficient. Only by controlling the braking of wheel Wi by the service brake system can the actual slip rate of wheel Wi be within the slip rate threshold range. If the braking torque compensation of wheel Wi is performed by controlling the power system and / or the parking brake system, the degree of vehicle sliding will be aggravated, and there is no need to perform braking torque compensation on wheel Wi, that is, the power system and the parking brake system are not used to perform braking torque compensation on wheel Wi.

[0118] In a possible implementation, after the vehicle braking system is controlled to apply a braking torque to the wheel based on the second target braking torque, the vehicle control method further includes the following steps:

[0119] When the second condition is met, limiting the steering wheel rotation;

[0120] The second condition includes at least one of the longitudinal acceleration of the vehicle being less than an acceleration threshold, the yaw angle being less than an angle threshold, the steering wheel rotation speed being greater than a rotation speed threshold, and there being no obstacles in the rear environment of the vehicle.

[0121] The vehicle's longitudinal acceleration is less than the acceleration threshold, indicating that the vehicle is stationary or sliding down at a low speed. The yaw angle is less than the angle threshold, indicating that the vehicle has almost no lateral movement. The steering wheel rotation speed is greater than the rotation speed threshold, indicating that the steering wheel rotation range is large and the driver may be panicked. There are no obstacles in the rear environment of the vehicle, indicating that the vehicle's reversing path is safe.

[0122] If it is determined that the vehicle meets the second condition, the steering wheel rotation is restricted to prevent the vehicle from rolling over due to the driver's excessive nervousness and panic in steering when the vehicle is going downhill or sliding down a slope. Specifically, restricting the steering wheel rotation is to control the steering wheel power motor to output a damping force to prevent the driver from turning the steering wheel as much as possible, and after restricting the steering wheel rotation, remind the driver not to turn the steering wheel to avoid the abnormal state of the vehicle caused by the driver's misoperation.

[0123] In a possible implementation, the vehicle control method further includes the following steps:

[0124] Upon receiving an activation instruction for an off-road assist function of the vehicle, obtaining an actual slope of a road on which the vehicle is located;

[0125] If the actual slope is greater than the slope threshold, and the vehicle's driving direction is the same as the slope direction of the road, it is determined whether the vehicle has a preset phenomenon during climbing.

[0126] The vehicle has an off-road assist function, which can be activated by a function switch. After the function switch is triggered, an activation command for the off-road assist function is issued. When the activation command for the off-road assist function is received, the off-road assist function is not activated immediately, but it is determined whether the actual slope of the road where the vehicle is located is greater than the slope threshold. If it is determined that the actual slope is greater than the slope threshold, and the driving direction of the vehicle is the same as the slope direction of the road, it is considered that the vehicle is climbing, and the off-road assist function is activated, and then it is determined whether a preset phenomenon occurs during the climbing period of the vehicle. If it is determined that the preset phenomenon occurs during the climbing period of the vehicle, the off-road assist control operation is executed, that is, S110-S150 is executed.

[0127] In a possible implementation, the above-mentioned obtaining the actual slope of the road on which the vehicle is located includes the following steps:

[0128] determining a first slope of the road based on the longitudinal acceleration of the vehicle;

[0129] Obtaining a second slope of the road identified by the intelligent driving system of the vehicle;

[0130] If the deviation between the first slope and the second slope is less than or equal to the deviation threshold, determining the first slope or the second slope as the actual slope;

[0131] If the deviation value is greater than the deviation threshold, multiple longitudinal accelerations are continuously obtained within a preset time period;

[0132] A plurality of third slopes of the road are determined according to the plurality of longitudinal accelerations, and an average value of the plurality of third slopes is determined as the actual slope.

[0133] There are two ways to calculate the actual slope of the road where the vehicle is located. The first way is to calculate the first slope of the road where the vehicle is located through the longitudinal acceleration of the vehicle, and at the same time identify the second slope of the road where the vehicle is located through the radar system in the intelligent driving system, and then determine whether the deviation value between the first slope and the second slope is less than or equal to the deviation threshold. If yes, it means that the first slope and the second slope are the same or close, then the first slope or the second slope is determined as the actual slope. If not, the second way is used to calculate the actual slope, that is, to continuously obtain multiple longitudinal accelerations within a preset time length, such as 20 longitudinal accelerations, and calculate a third slope through each of the 20 longitudinal accelerations to obtain 20 third slopes, and calculate the average value of these 20 third slopes to obtain the actual slope.

[0134] In order to ensure that the vehicle's various systems, power batteries, etc. can function effectively when there is a risk of stability, it is necessary to detect the status information of the above systems, power batteries, etc. to decide whether the off-road assistance function can be activated.

[0135] Situations in which the off-road assistance function is activated include:

[0136] 1. The service brake system can brake, and all the drive motors in the power system cannot participate in the braking torque compensation, but the parking brake system can participate in the braking torque compensation, then the off-road assist function is allowed to be activated, and the braking torque compensation is performed only through the parking brake system. Among them, any one of the battery temperature of the power battery is greater than or equal to the third temperature threshold, the remaining power of the power battery is less than or equal to the power threshold, and the motor output power of all the drive motors is less than or equal to the power threshold is a factor that causes all the drive motors in the power system to be unable to participate in the braking torque compensation.

[0137] 2. If the service brake system can brake and all drive motors in the power system can participate in the braking torque compensation, but the parking brake system cannot participate in the braking torque compensation, then the off-road assist function is allowed to be activated and the braking torque compensation is only performed through the power system.

[0138] 3. The service brake system can brake, and part of the drive motors in the power system can participate in braking torque compensation, while the other part of the drive motors cannot participate in braking torque compensation. The off-road assist function can be activated, and braking torque compensation is performed by the drive motors in the power system that can participate in braking torque compensation. The parking brake system is used to replace the drive motors in the power system that cannot participate in braking torque compensation to perform braking torque compensation.

[0139] 4. The service brake system can brake, and part of the parking calipers in the parking brake system can participate in the braking torque compensation, while the other part of the parking calipers cannot participate in the braking torque compensation. The off-road assist function is allowed to be activated, and the parking calipers in the parking brake system that can participate in the braking torque compensation are used to perform braking torque compensation, and the driving motor corresponding to the parking calipers that cannot participate in the braking torque compensation in the power system is used to replace the parking calipers that cannot participate in the braking torque compensation. For example, if the parking caliper of the right rear wheel cannot perform braking torque compensation on the right rear wheel, the driving motor of the right rear wheel replaces the parking caliper of the right rear wheel to perform braking torque compensation on the right rear wheel.

[0140] 5. The tire pressure and brake disc temperature are normal, and the off-road assistance function can be activated; the temperature of the steering wheel power motor in the steering system and the response performance of the steering system are normal, and the off-road assistance function can be activated; the suspension system is in normal condition, and the off-road assistance function can be activated.

[0141] Situations where activation of the off-road assistance function is prohibited include:

[0142] 1. The service brake system cannot brake and the off-road assist function cannot be activated.

[0143] 2. If the tire pressure or brake disc temperature is abnormal, the off-road assist function cannot be activated.

[0144] 3. If the temperature of the steering wheel power motor in the steering system is abnormal or the response performance of the steering system is abnormal, the off-road assist function cannot be activated;

[0145] 4. The suspension system is in an abnormal state and it is prohibited to activate the off-road assist function.

[0146] Among them, when the off-road assist function is prohibited from being activated, a reminder message will be output to remind the driver to stop driving the vehicle for off-road operations.

[0147] In a possible implementation, if it is determined through the matching degree that the actual slip rate of the wheel Wi needs to be calculated through the second calculation strategy, and an abnormality occurs in the suspension system, and the suspension parameters cannot be obtained or accurate suspension parameters cannot be obtained, that is, the actual slip rate of the wheel Wi calculated based on the second calculation strategy is meaningless, then the actual slip rate of the wheel Wi calculated by the first calculation strategy is used, and after the service brake system is controlled to apply a braking torque to the wheel based on the second target braking torque, if it is determined that the actual slip rate of the wheel Wi is less than the minimum value of the slip rate threshold interval, the target drive motor is controlled according to a time-torque curve with a first slope, Output a compensating braking torque, or control the parking brake system to output the compensating braking torque according to a time-torque curve with a second slope, or control the target drive motor to output a third stall torque according to a time-torque curve with a first slope, and control the parking brake system to output a third parking braking torque according to a time-torque curve with a second slope, the sum of the third stall torque and the third parking braking torque is the compensating braking torque, until the actual slip rate of the wheel Wi is within the slip rate threshold range, so that even if the suspension parameters cannot be accurately obtained, the wheel Wi can be braked for compensation, which is beneficial to improve the reliability of braking compensation for the wheel Wi.

[0148] It is worth noting that the above description is about the vehicle braking control of the vehicle with the front end facing up during the period of reversing or sliding down a slope. Similarly, the vehicle control method provided in the embodiment of the present application is also applicable to the vehicle braking control of the vehicle when the front end is facing down during the period of downhill. No matter it is a reversing or sliding down a slope scenario with the front end facing up, or a downhill scenario with the front end facing down, by adopting the vehicle control method provided in the embodiment of the present application, the stability of the vehicle on the slope can be ensured, and the safety of the vehicle in off-road scenarios can be improved.

[0149] The following is an embodiment of the device of the present application, which can be used to execute the embodiment of the method of the present application. For details not disclosed in the embodiment of the device of the present application, please refer to the embodiment of the method of the present application.

[0150] Figure 4A schematic diagram of the structure of a vehicle control device provided in an embodiment of the present application is shown. Figure 4 As shown, the vehicle control device 400 includes:

[0151] A first acquisition module 410 is configured to, when it is determined that a preset phenomenon occurs during the climbing of the vehicle, if a first brake pedal stroke is received, acquire, for each wheel, a first target braking torque allocated to the wheel according to the first brake pedal stroke; wherein the preset phenomenon is a phenomenon that the vehicle slides downward on the slope due to gravity;

[0152] The torque adjustment module 420 is used to reduce the first target braking torque to obtain a second target braking torque corresponding to the wheel when the first target braking torque is greater than the wheel braking torque extreme value; wherein the second target braking torque is less than the wheel braking extreme value;

[0153] A braking control module 430, configured to control a service braking system to apply a braking torque to the wheel based on the second target braking torque;

[0154] A second acquisition module 440 is used to acquire an actual slip rate of the wheel;

[0155] The braking compensation module 450 is used to control the power system and / or the parking brake system to perform braking torque compensation on the wheel when the actual slip rate is less than the minimum value of the slip rate threshold range, so that the actual slip rate is within the slip rate threshold range.

[0156] In a possible implementation, the braking compensation module 450 includes:

[0157] an acquisition unit, configured to acquire a second brake pedal stroke and an actual braking torque applied to the wheel by the service brake system when the actual slip rate is less than a minimum value of a slip rate threshold interval;

[0158] A compensation unit is used to control the power system and / or the parking brake system to perform braking torque compensation on the wheel if the second brake pedal stroke is greater than the first brake pedal stroke and the actual braking torque is less than the wheel braking torque extreme value.

[0159] In a possible implementation, the compensation unit includes:

[0160] a first compensation subunit, configured to control a target drive motor in the power system to output a first stall torque, use the first stall torque as a compensation braking torque, and apply the first stall torque to the wheel;

[0161] a second compensation subunit, configured to control the parking brake system to output a first parking braking torque, use the first parking braking torque as the compensation braking torque, and apply the first parking braking torque to the wheel;

[0162] a third compensation subunit, configured to control the target drive motor in the power system to output a second stall torque, control the target drive motor in the power system to output the second stall torque, use the sum of the second stall torque and the second parking braking torque as the compensation braking torque, and apply it to the wheel;

[0163] Among them, the target drive motor is the drive motor that drives the wheel, the first stall torque and the second stall torque are opposite to the direction of the drive torque output by the target drive motor, and the compensation braking torque is the difference between the wheel braking torque extreme value and the actual braking torque.

[0164] In a possible implementation, the first compensation subunit is used to control the target drive motor in the power system to output a first stall torque when the target drive motor satisfies a first condition;

[0165] Among them, the first condition includes that the ambient temperature is lower than the first temperature threshold, the motor temperature is lower than the second temperature threshold, the battery temperature of the power battery is lower than the third temperature threshold, the remaining power of the power battery is greater than the power threshold and the motor output power is greater than the power threshold.

[0166] In a possible implementation, the first compensation subunit is used to control the target drive motor to output the first stall torque according to a time-torque curve with a first slope.

[0167] The second compensation subunit is used to control the parking brake system to output the first parking brake torque according to a time-torque curve with a second slope.

[0168] In a possible implementation, the vehicle control device 400 further includes:

[0169] The first calculation unit is used to determine the first wheel vertical load of the wheel according to the suspension height change corresponding to the wheel and the actual slope of the road on which the vehicle is located; and obtain the wheel braking torque extreme value according to the product of the first wheel vertical load and the actual slip rate.

[0170] In a possible implementation, the second acquisition module 440 includes:

[0171] An image acquisition unit, used to acquire a road image of the road on which the vehicle is located;

[0172] A second calculation unit, used to determine the matching degree between the road image and a preset road image;

[0173] The third calculation unit is used to determine the actual slip rate of the wheel according to the matching degree.

[0174] In a possible implementation, the third computing unit includes:

[0175] The first calculation subunit is used to obtain the actual vehicle speed and the linear speed of the wheel if the matching degree is greater than the matching degree threshold; and determine the actual slip rate of the wheel according to the actual vehicle speed and the linear speed.

[0176] In a possible implementation, the third computing unit includes:

[0177] a second calculation subunit, for determining the second wheel vertical load of the wheel according to the suspension parameters of the vehicle suspension if the matching degree is less than or equal to the matching degree threshold; wherein the suspension parameters include at least one of the suspension deformation, the suspension stiffness and the damping coefficient; determining the wheel longitudinal load of the wheel according to the first target braking torque and the target torque issued by the power system; wherein the target torque is the driving torque or the recovery torque; determining the road adhesion coefficient according to the ratio of the wheel longitudinal load to the second wheel vertical load; wherein the road adhesion coefficient includes a plurality of adhesion coefficient values; determining the derivative of the road adhesion coefficient to the slip rate during the slipping process of the wheel to obtain a plurality of derivative values; determining the adhesion coefficient value corresponding to the target derivative value as the actual slip rate of the wheel; wherein the target derivative value is a derivative value among the plurality of derivative values ​​whose difference from 0 is less than a preset difference.

[0178] In one possible implementation, the second calculation subunit is used to determine the second wheel vertical load of the wheel according to the suspension parameters of the vehicle suspension, and is specifically used to determine the load transfer amount of the wheel according to the suspension deformation, the suspension stiffness and the damping coefficient; determine the unsprung mass transfer amount according to the load transfer amount; obtain the sprung load according to the suspension deformation; and obtain the second wheel vertical load according to the unsprung mass, the unsprung mass transfer amount and the sprung load.

[0179] In a possible implementation, the vehicle control device further includes:

[0180] The torque reduction unit is used to control the power system and / or the parking brake system to reduce the compensating braking torque applied to the wheel in accordance with a gradient descent strategy in response to a reset signal of the brake pedal.

[0181] In a possible implementation, the vehicle control device 400 further includes:

[0182] The system disabling unit is used to prohibit controlling the power system and the parking brake system to perform braking torque compensation on the wheels when the actual slip rates of the wheels are all greater than the maximum value of the slip rate threshold range.

[0183] In a possible implementation, the vehicle control device 400 further includes:

[0184] A steering wheel limiting unit, used to limit the rotation of the steering wheel when the second condition is met;

[0185] The second condition includes at least one of the longitudinal acceleration of the vehicle being less than an acceleration threshold, the yaw angle being less than an angle threshold, the steering wheel rotation speed being greater than a rotation speed threshold, and the absence of obstacles in the rear environment of the vehicle.

[0186] In a possible implementation, the vehicle control device 400 further includes:

[0187] a fourth calculation unit, configured to obtain an actual slope of a road on which the vehicle is located when receiving an activation instruction for an off-road assist function of the vehicle;

[0188] A judgment unit is used to judge whether the preset phenomenon occurs during the climbing of the vehicle if the actual slope is greater than a slope threshold and the driving direction of the vehicle is the same as the slope direction of the road.

[0189] In one possible implementation, the fourth calculation unit is specifically used to determine the first slope of the road according to the longitudinal acceleration of the vehicle; obtain the second slope of the road identified by the intelligent driving system of the vehicle; if the deviation value between the first slope and the second slope is less than or equal to the deviation threshold, determine the first slope or the second slope as the actual slope; if the deviation value is greater than the deviation threshold, continuously obtain multiple longitudinal accelerations within a preset time length; determine multiple third slopes of the road according to the multiple longitudinal accelerations, and determine the average value of the multiple third slopes as the actual slope.

[0190] It should be noted that the vehicle control device provided in the above embodiment only uses the division of the above functional modules as an example when executing the vehicle control method. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the vehicle control device provided in the above embodiment belongs to the same concept as the vehicle control method embodiment. Therefore, for details not disclosed in the device embodiment of the present application, please refer to the above-mentioned vehicle control method embodiment of the present application, which will not be repeated here.

[0191] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0192] Figure 5 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application is shown. Figure 5 As shown, the vehicle 500 includes: a memory 501 and a processor 502, wherein the memory 501 stores an executable program code 5011, and the processor 502 is used to call and execute the executable program code 5011 to perform a vehicle control method.

[0193] In this embodiment, the functional modules of the vehicle can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0194] In the case of dividing each functional module according to each function, the vehicle may include: a first acquisition module, a torque adjustment module, a brake control module, a second acquisition module, a brake compensation module, etc. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0195] The vehicle provided in this embodiment is used to execute the above-mentioned vehicle control method, and thus can achieve the same effect as the above-mentioned implementation method.

[0196] In the case of an integrated unit, the vehicle may include a processing module and a storage module. The processing module may be used to control and manage the actions of the vehicle. The storage module may be used to support the vehicle in executing relevant program codes and data.

[0197] The processing module may be a processor or a controller, which may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory.

[0198] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement a vehicle control method in the above-mentioned embodiment.

[0199] This embodiment also provides a computer program product. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned related steps to implement a vehicle control method in the above-mentioned embodiment.

[0200] In addition, the vehicle provided in the embodiments of the present application may specifically be a chip, component or module, and the vehicle may include a connected processor and memory; wherein the memory is used to store instructions, and when the vehicle is running, the processor may call and execute instructions so that the chip executes a vehicle control method in the above embodiments.

[0201] Among them, the vehicle, computer-readable storage medium, computer program product or chip provided in this embodiment are all used to execute the corresponding vehicle control method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding vehicle control method provided above, and will not be repeated here.

[0202] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0203] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0204] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A vehicle control method, characterized in that: The vehicle control method comprises: When it is determined that a preset phenomenon occurs during the climbing of the vehicle, if a first brake pedal stroke is received, for each wheel, a first target braking torque allocated to the wheel is obtained according to the first brake pedal stroke; wherein the preset phenomenon is a phenomenon that the vehicle slides downward on the slope due to gravity; When the first target braking torque is greater than the wheel braking torque extreme value, reducing the first target braking torque to obtain a second target braking torque corresponding to the wheel; wherein the second target braking torque is less than the wheel braking extreme value; controlling a service braking system to apply a braking torque to the wheel based on the second target braking torque; Obtaining an actual slip rate of the wheel; When the actual slip ratio is less than a minimum value of the slip ratio threshold range, the power system and / or the parking brake system is controlled to perform braking torque compensation on the wheels so that the actual slip ratio is within the slip ratio threshold range.

2. The vehicle control method according to claim 1, characterized in that: When the actual slip rate is less than the minimum value of the slip rate threshold range, controlling the power system and / or the parking brake system to perform braking torque compensation on the wheel includes: When the actual slip rate is less than a minimum value of a slip rate threshold interval, obtaining a second brake pedal stroke and an actual braking torque applied to the wheel by the service brake system; If the second brake pedal travel is greater than the first brake pedal travel and the actual braking torque is less than the wheel braking torque limit, the power system and / or the parking brake system is controlled to perform braking torque compensation on the wheels.

3. The vehicle control method according to claim 2, characterized in that: The controlling the power system and / or the parking brake system to perform braking torque compensation on the wheels includes at least one of the following: Controlling a target drive motor in the power system to output a first stall torque, using the first stall torque as a compensation braking torque, and applying the first stall torque to the wheel; controlling the parking brake system to output a first parking braking torque, using the first parking braking torque as the compensation braking torque, and applying the first parking braking torque to the wheel; Controlling the target drive motor in the power system to output a second stall torque, controlling the target drive motor in the power system to output a second stall torque, taking the sum of the second stall torque and the second parking braking torque as the compensation braking torque, and applying it to the wheel; Among them, the target drive motor is the drive motor that drives the wheel, the first stall torque and the second stall torque are opposite to the direction of the drive torque output by the target drive motor, and the compensation braking torque is the difference between the wheel braking torque extreme value and the actual braking torque.

4. The vehicle control method according to claim 3, characterized in that: The vehicle control method further includes: When the target drive motor satisfies a first condition, executing the step of controlling the target drive motor in the power system to output a first stall torque; Among them, the first condition includes that the ambient temperature is lower than the first temperature threshold, the motor temperature is lower than the second temperature threshold, the battery temperature of the power battery is lower than the third temperature threshold, the remaining power of the power battery is greater than the power threshold and the motor output power is greater than the power threshold.

5. The vehicle control method according to claim 4, characterized in that: The controlling the target drive motor in the power system to output a first stall torque comprises: controlling the target drive motor to output the first stall torque according to a time-torque curve having a first slope; The controlling the parking brake system to output a first parking brake torque comprises: The parking brake system is controlled to output the first parking brake torque according to a time-torque curve having a second slope.

6. The vehicle control method according to claim 2, characterized in that: The vehicle control method further includes: Determining a first wheel vertical load of the wheel according to a change in suspension height corresponding to the wheel and an actual slope of a road on which the vehicle is located; The wheel braking torque extreme value is obtained according to the product of the first wheel vertical load and the actual slip rate.

7. The vehicle control method according to claim 2, characterized in that: The obtaining of the actual slip rate of the wheel comprises: Acquire a road image of the road on which the vehicle is located; Determining a degree of matching between the road image and a preset road image; The actual slip rate of the wheel is determined according to the matching degree.

8. The vehicle control method according to claim 7, characterized in that: Determining the actual slip rate of the wheel according to the matching degree includes: If the matching degree is greater than a matching degree threshold, obtaining the actual vehicle speed and the linear speed of the wheel; An actual slip rate of the wheel is determined according to the actual vehicle speed and the linear speed.

9. The vehicle control method according to claim 7, characterized in that: Determining the actual slip rate of the wheel according to the matching degree includes: If the matching degree is less than or equal to the matching degree threshold, determining the second wheel vertical load of the wheel according to the suspension parameters of the vehicle suspension; wherein the suspension parameters include at least one of the suspension deformation, the suspension stiffness and the damping coefficient; determining the wheel longitudinal load of the wheel according to the first target braking torque and the target torque generated by the powertrain; wherein the target torque is a driving torque or a recovery torque; Determining a road adhesion coefficient according to a ratio of the wheel longitudinal load to the second wheel vertical load; wherein the road adhesion coefficient includes a plurality of adhesion coefficient values; Determining the derivative of the road adhesion coefficient to the slip rate during the slipping process of the wheel to obtain a plurality of derivative values; The adhesion coefficient value corresponding to the target derivative value is determined as the actual slip rate of the wheel; wherein the target derivative value is a derivative value among the multiple derivative values ​​whose difference from 0 is less than a preset difference.

10. The vehicle control method according to claim 9, characterized in that: The determining the second wheel vertical load of the wheel according to the suspension parameters of the vehicle suspension comprises: determining a load transfer amount of the wheel according to the suspension deformation amount, the suspension stiffness and the damping coefficient; determining an unsprung mass transfer amount based on the load transfer amount; Obtaining a sprung load according to the suspension deformation; The second wheel vertical load is obtained according to the unsprung mass, the unsprung mass transfer amount and the sprung load.

11. The vehicle control method according to claim 3, characterized in that: After the control power system and / or the parking brake system performs braking torque compensation on the wheels, the vehicle control method further includes: In response to a reset signal of the brake pedal, the power system and / or the parking brake system is controlled according to a gradient descent strategy to reduce the compensating braking torque applied to the wheels.

12. The vehicle control method according to claim 1, characterized in that: After obtaining the actual slip rate of the wheel, the vehicle control method further includes: When the actual slip rates of the wheels are all greater than the maximum value of the slip rate threshold range, controlling the power system and the parking brake system to perform braking torque compensation on the wheels is prohibited.

13. The vehicle control method according to claim 1, characterized in that: After the service brake system is controlled to apply a braking torque to the wheel based on the second target braking torque, the vehicle control method further includes: When the second condition is met, limiting the steering wheel rotation; The second condition includes at least one of the longitudinal acceleration of the vehicle being less than an acceleration threshold, the yaw angle being less than an angle threshold, the steering wheel rotation speed being greater than a rotation speed threshold, and the absence of obstacles in the rear environment of the vehicle.

14. The vehicle control method according to claim 1, characterized in that: The vehicle control method further includes: Upon receiving an activation instruction for an off-road assist function of the vehicle, obtaining an actual slope of a road on which the vehicle is located; If the actual slope is greater than the slope threshold, and the driving direction of the vehicle is the same as the slope direction of the road, it is determined whether the preset phenomenon occurs during the climbing of the vehicle.

15. The vehicle control method according to claim 14, characterized in that: The obtaining of the actual slope of the road on which the vehicle is located comprises: determining a first slope of the road based on the longitudinal acceleration of the vehicle; Acquire a second slope of the road identified by the intelligent driving system of the vehicle; If the deviation between the first slope and the second slope is less than or equal to a deviation threshold, determining the first slope or the second slope as the actual slope; If the deviation value is greater than the deviation threshold, continuously acquiring a plurality of longitudinal accelerations within a preset time period; A plurality of third slopes of the road are determined according to the plurality of longitudinal accelerations, and an average value of the plurality of third slopes is determined as the actual slope.

16. A vehicle, characterized in that: The vehicle comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory so that the vehicle executes the vehicle control method as described in any one of claims 1 to 15.

17. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the vehicle control method according to any one of claims 1 to 15 is implemented.

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