Control method for a vehicle

Abstract

The application discloses a control method of a vehicle, which comprises the following steps: acquiring the opening degree of a brake pedal; if the opening degree of the brake pedal is in a deceleration allowable variation range, the braking force of a main vehicle motor is adjusted according to the opening degree of the brake pedal, and the deceleration allowable variation range comprises a plurality of braking intervals, and the proportion of the braking force of the main vehicle motor in the braking force of the whole vehicle decreases with the increase of the braking intervals as a whole. The control method of the vehicle has the advantages of high energy recovery rate, more coordinated braking, high braking safety and the like.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a vehicle control method. Background Technology

[0002] Vehicles in related technologies typically brake simultaneously using electric braking and air braking at a fixed braking ratio. The braking force of the air brake is linearly coupled with the opening of the vehicle's brake pedal. However, vehicles in these technologies exhibit poor coordination during braking. When the overall vehicle braking force is low, the electric braking force is low, which can easily lead to low braking energy recovery efficiency. Conversely, when the overall vehicle braking force is high, the electric braking force is high, which can easily cause the rear axle of the main vehicle to lock up, leading to dangers such as skidding or fishtailing, resulting in low braking safety. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. Therefore, one object of the present invention is to provide a vehicle control method that has advantages such as high energy recovery rate, more coordinated braking, and high braking safety.

[0004] To achieve the above objectives, a vehicle control method is proposed according to an embodiment of the present invention, comprising: acquiring the opening degree of a brake pedal; if the opening degree of the brake pedal is within the allowable range of deceleration variation, adjusting the braking force of the main vehicle motor according to the opening degree of the brake pedal, wherein the allowable range of deceleration variation includes multiple braking intervals, and the proportion of the braking force of the main vehicle motor in the total vehicle braking force decreases as the overall braking interval increases.

[0005] The vehicle control method according to the embodiments of the invention has advantages such as high energy recovery rate, more coordinated braking and high braking safety.

[0006] According to some embodiments of the present invention, the plurality of braking ranges include a small braking range, a medium braking range, and a large braking range; if the brake pedal is in the small braking range, the vehicle mass m, the target deceleration a, and the actual deceleration a0 are obtained, and the braking force F of the main vehicle motor is F = ma + F0, where F0 is a braking force correction value and is adjusted according to the target deceleration and the actual deceleration; if the brake pedal is in the medium braking range, the vehicle speed is obtained, and the braking force of the main vehicle motor is adjusted according to the opening of the brake pedal and the vehicle speed; if the brake pedal is in the large braking range, the main vehicle motor stops outputting braking force.

[0007] According to some embodiments of the present invention, if the brake pedal is in the medium braking range, the trailer air brake is activated, and the braking force ratio of the main vehicle and the trailer is adjusted to meet the rear axle adhesion utilization coefficient; it is determined whether the braking force of the main vehicle motor meets the braking force of the main vehicle; if yes, the main vehicle motor provides the braking force of the main vehicle; if no, the air brake of the main vehicle front axle is activated. According to some embodiments of the present invention, if the brake pedal is in the small braking range, it is determined whether the braking force of the main vehicle motor meets the braking force required for the target deceleration; if yes, the main vehicle motor provides braking force for the vehicle alone; if no, the air brake of the main vehicle front axle is activated.

[0008] According to some embodiments of the present invention, the vehicle has multiple load levels, and the threshold value of the target deceleration increases with the increase of the load level within the same braking range; the target deceleration increases with the increase of the braking range within the same load level. According to some embodiments of the present invention, the multiple load levels include an unloaded level, a half-loaded level, and a fully loaded level; when the brake pedal is in the low braking range: if the vehicle is in the unloaded level, the target deceleration is less than 0.05g; if the vehicle is in the half-loaded level, the target deceleration is less than 0.1g; if the vehicle is in the fully loaded level, the target deceleration is less than 0.15g; when the brake pedal is in the medium braking range: if the vehicle is in the unloaded level, the target deceleration is greater than 0.05g. And less than 0.2g; if the vehicle is in the half-load level, the target deceleration is less than 0.1g and less than 0.25g; if the vehicle is in the full-load level, the target deceleration is less than 0.15g and less than 0.3g; when the brake pedal is in the maximum braking range: if the vehicle is in the unload level, the target deceleration is greater than 0.2g; if the vehicle is in the half-load level, the target deceleration is less than 0.25g; if the vehicle is in the full-load level, the target deceleration is less than 0.3g; where g is the acceleration due to gravity.

[0009] According to some embodiments of the present invention, the allowable range of the opening degree is 8% to 75% of the maximum opening degree of the brake pedal.

[0010] According to some embodiments of the present invention, the vehicle control method includes: acquiring the overall vehicle status; determining whether the overall vehicle status meets the regenerative braking conditions; if yes, controlling the main vehicle motor to output braking force; if no, controlling the main vehicle motor to stop outputting braking force.

[0011] According to some embodiments of the present invention, determining whether the vehicle state meets the braking regeneration conditions includes: acquiring the vehicle speed and the remaining charge of the battery pack; determining whether the vehicle speed is greater than a preset vehicle speed and whether the remaining charge of the battery pack is less than a preset charge; if so, acquiring the yaw rate of the vehicle and the road surface adhesion coefficient; determining whether the yaw rate is not greater than a preset yaw rate or whether the road surface adhesion coefficient is not less than a preset coefficient; if so, controlling the main vehicle motor to output braking force.

[0012] According to some embodiments of the present invention, the preset vehicle speed is not less than 10 km / h, the preset battery level is not greater than 90%, the preset yaw rate is not greater than 6° / second, and the preset coefficient is adjusted according to the vehicle speed.

[0013] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0014] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0015] Figure 1 This is a flowchart of a vehicle control method according to an embodiment of the present invention.

[0016] Figure 2 This is another flowchart of a vehicle control method according to an embodiment of the present invention.

[0017] Figure 3 This is a schematic diagram showing the distribution of braking deceleration of a vehicle at different speeds according to an embodiment of the present invention. Detailed Implementation

[0018] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] In the description of this invention, "first feature" and "second feature" may include one or more of the features.

[0021] In the description of this invention, "a plurality of" means two or more, and "several" means one or more.

[0022] The vehicle control method according to an embodiment of the present invention is described below with reference to the accompanying drawings.

[0023] like Figures 1-3 As shown, the vehicle control method according to an embodiment of the present invention includes:

[0024] Obtain the brake pedal opening;

[0025] If the brake pedal opening is within the allowable range of deceleration variation, the braking force of the main vehicle motor is adjusted according to the brake pedal opening. The allowable range of deceleration variation includes multiple braking intervals, and the proportion of the braking force of the main vehicle motor in the total vehicle braking force decreases as the overall braking interval increases.

[0026] Generally, the larger the brake pedal opening, the greater the distance the driver needs to press the brake pedal, and the greater the braking force of the vehicle. Conversely, the smaller the brake pedal opening, the less the distance the driver needs to press the brake pedal, and the less the braking force of the vehicle.

[0027] The vehicles can be heavy trucks, trailers, or freight trucks, etc. The main vehicle can be braked by air brakes and electric brakes from the main vehicle motor, while the trailer can be braked by air brakes.

[0028] For example, the allowable range of brake pedal opening can be 8% to 75% of the maximum brake pedal opening. Thus, when the brake pedal opening is 0% to 8% of its maximum opening, this segment of travel is the pedal's free travel. In other words, when the brake pedal opening is between 0% and 8%, the wheels do not generate braking force. This is more in line with the driver's driving habits, providing a buffer for braking operations and preventing the driver from accidentally pressing the brake pedal too frequently, thus avoiding excessively sensitive brake pedal response and poor braking feedback comfort. It also effectively prevents the brake pads and discs from overheating due to excessive tension, thereby preventing brake failure and making braking operation more comfortable.

[0029] According to the vehicle control method of the present invention, the braking force of the main vehicle motor is adjusted according to the opening of the brake pedal, and the deceleration is allowed to vary within multiple braking ranges. Thus, the braking intensity is different in different braking ranges. The braking range with greater braking intensity corresponds to greater deceleration and greater braking force. In other words, the greater the braking intensity, the shorter the time required for the vehicle to stop when braking at the same speed.

[0030] The braking intensity varies across multiple braking zones. This can be understood as the minimum braking intensity in a braking zone with higher braking intensity not being less than the maximum braking intensity in a braking zone with lower braking intensity.

[0031] In addition, the proportion of the braking force of the main vehicle motor in the total braking force of the vehicle decreases as the overall braking range increases. That is to say, when the brake pedal is in the braking range with lower braking intensity, the proportion of the braking force of the main vehicle motor in the total braking force of the vehicle is larger, and when the brake pedal is in the braking range with higher braking intensity, the proportion of the braking force of the main vehicle motor in the total braking force of the vehicle is smaller.

[0032] Understandably, by Figure 3 As shown in the diagram, the distribution of braking deceleration of a vehicle at different speeds is as follows: when a vehicle is traveling at different speeds, the driver uses low-intensity braking more frequently. By increasing the proportion of the braking force of the main vehicle motor to the total braking force of the vehicle during low-intensity braking, the vehicle can use the electric braking force of the main vehicle motor to brake the vehicle more during low-intensity braking, thereby improving the efficiency of braking energy recovery and reducing the overall vehicle power consumption.

[0033] Furthermore, when the vehicle is braking in a braking range with high braking intensity, the smaller the proportion of the braking force of the main vehicle motor in the total braking force of the vehicle, the more the trailer can use air brakes in conjunction with the braking force of the main vehicle motor to brake the vehicle. This makes the braking force more coordinated in the front and rear directions of the vehicle, avoiding excessive electric braking force on the rear axle of the main vehicle, which could cause the rear axle to lock up. This helps to avoid dangers such as tail swing, sideslip, overturning, or understeer, thus improving vehicle braking safety and driving safety.

[0034] Thus, the vehicle control method according to the embodiments of the invention has advantages such as high energy recovery rate, more coordinated braking, and high braking safety.

[0035] In some specific embodiments of the present invention, such as Figure 1 As shown, the multiple braking ranges include small braking range, medium braking range and large braking range;

[0036] If the brake pedal is in the small braking range, the vehicle mass m, target deceleration a, and actual deceleration a0 are obtained, and the braking force of the main vehicle motor F = ma + F0, where F0 is the braking force correction value and is adjusted according to the target deceleration a and actual deceleration a0; if the brake pedal is in the medium braking range, the vehicle speed is obtained, and the braking force of the main vehicle motor is adjusted according to the brake pedal opening and vehicle speed; if the brake pedal is in the large braking range, the main vehicle motor stops outputting braking force.

[0037] Specifically, when the brake pedal is in the low braking range, the main vehicle motor can provide all the braking force. First, the braking regenerative torque *ma* of the main vehicle motor is calculated. Then, the braking force is corrected based on feedback PID (Proportional Integral Derivative) control, and the difference between the target deceleration *a* and the actual deceleration *a0* is set as Δa, thus determining the corrected braking force value. Among them, K P K I and K D This is for calibration during real vehicle testing.

[0038] Furthermore, when the brake pedal is in the medium braking range, as the pedal opening gradually increases, the proportion of the main motor's braking force in the total vehicle braking force can gradually decrease. Alternatively, when the brake pedal is in the medium braking range, with the same pedal opening, the faster the vehicle speed, the smaller the proportion of the main motor's braking force in the total vehicle braking force can be. In other words, in the medium braking range, when the brake pedal opening is relatively small, the main motor's braking force can still account for a relatively large proportion of the total vehicle braking force to improve the vehicle's braking energy recovery efficiency in the medium braking range. As the brake pedal opening gradually increases, the proportion of the main motor's braking force in the total vehicle braking force gradually decreases, thus avoiding excessive braking force from the main motor at higher vehicle speeds. This prevents the rear axle brakes from locking up, more effectively avoiding dangers such as fishtailing, skidding, overturning, or understeer, and improving vehicle braking safety.

[0039] Furthermore, when the brake pedal is in the high braking range, the main vehicle motor stops outputting braking force. In other words, when the vehicle's braking intensity is high and rapid braking is required, the main vehicle motor does not participate in the overall vehicle braking. At this time, the vehicle can be braked solely by the trailer air brake, thereby preventing the rear axle of the main vehicle from locking up. This further avoids dangers such as tail swing, sideslip, folding, or understeer, and further improves the vehicle's braking safety.

[0040] The estimated vehicle mass m can be obtained in the following ways:

[0041] First, from the vehicle dynamics equations

[0042] Among them, traction force F t Expression: F t =T aq i g i0η / r,i g i0 and η are the main reducer transmission ratio, gearbox transmission ratio, and transmission system mechanical efficiency, respectively; r is the rolling radius of the wheel, in meters.

[0043] Slope resistance F i Specific expression: F i =mgsini,i is the road slope angle;

[0044] air resistance F w Specific expression: F w =0.5C D Aρν 2 C D These are the air resistance coefficients, and A is the frontal area (in m²). 2 ), ρ is the air density (unit: kg / m³). 3) and v are the longitudinal speeds of the vehicle (in m / s);

[0045] The specific expression for rolling resistance is: F f =mgfcosi, where f is the rolling resistance coefficient of the vehicle.

[0046] After expansion

[0047] A load capacity estimation model is established by introducing the least squares method. Rewrite as a recursive least squares equation:

[0048]

[0049] Among them, y k H k Let m represent the system input, the observable data vector, and the system parameters to be estimated, respectively. Therefore, the recursive format for the vehicle mass can be expressed as:

[0050] Gain matrix K K And error covariance matrix P K It can be represented as:

[0051] Set the λ value, forgetting factor, and initial value. P0, through the gain matrix K K And error covariance matrix P K By continuously making corrections, the overall vehicle weight can be calculated recursively.

[0052] In some specific embodiments of the present invention, such as Figure 1 As shown, if the brake pedal is in the medium braking range, activate the trailer air brake and adjust the braking force ratio of the tractor and trailer to meet the rear axle adhesion utilization coefficient.

[0053] Determine whether the braking force of the main vehicle motor meets the braking force of the main vehicle;

[0054] If so, the main vehicle motor provides braking force to the main vehicle;

[0055] If not, activate the air brake on the front axle of the main vehicle.

[0056] In other words, when the brake pedal is in the medium braking range, the trailer air brake and the main vehicle motor first participate in the overall vehicle braking. When all the braking force of the main vehicle motor participates in the braking of the main vehicle, but still does not meet the braking force requirements of the main vehicle, the air brake of the front axle of the main vehicle then participates in the overall vehicle braking. In this way, the electric braking of the main vehicle motor and the air braking of the front axle of the main vehicle can simultaneously provide braking force to the main vehicle, thereby improving the braking force on the main vehicle, so that the vehicle can meet the overall vehicle braking requirements in the medium braking range, resulting in better braking performance.

[0057] Moreover, by adjusting the braking intensity to meet the rear axle adhesion utilization coefficient, the braking force of the tractor unit can be prevented from far exceeding that of the trailer. In other words, even if the air brakes on the front axle of the tractor unit participate in braking, the braking force of the tractor unit will not be too large relative to that of the trailer. This can meet the braking requirements of the tractor unit and prevent the trailer from experiencing dangers such as tail swing, skidding, folding, or understeer due to excessive braking force of the tractor unit, resulting in higher braking safety.

[0058] In some specific embodiments of the present invention, such as Figure 1 As shown, if the brake pedal is in the small braking range, it is determined whether the braking force of the main vehicle motor meets the braking force required for the target deceleration.

[0059] If so, the main motor provides braking force for the vehicle independently;

[0060] If not, activate the air brake on the front axle of the main vehicle.

[0061] Specifically, when the brake pedal is in the small braking range, the main vehicle motor provides all the braking force of the main vehicle, and the trailer air brake does not participate in braking. At this time, the electric braking of the main vehicle motor accounts for 100% of the total braking force of the vehicle, which is conducive to improving the energy recovery efficiency of the vehicle braking. As the braking intensity in the small braking range gradually increases, the braking force of the main vehicle motor participates in the main vehicle braking, but it still does not meet the braking force required for the target deceleration. At this time, the air brake of the front axle of the main vehicle participates in braking, which can improve the braking force of the main vehicle, so that the vehicle can meet the braking force required for the target deceleration in the small braking range, resulting in better braking effect.

[0062] In some specific embodiments of the present invention, such as Figure 1 As shown, the vehicle has multiple load levels. Within the same braking range, the threshold of the target deceleration increases with the increase of the load level, and within the same load level, the target deceleration increases with the increase of the braking range.

[0063] In this way, as the vehicle's load level gradually increases, the threshold of the target deceleration in the same braking range gradually increases. That is to say, the greater the vehicle's overall mass, the greater the maximum value of the target deceleration in the same braking range. Since the greater the vehicle's overall mass, the greater the vehicle's overall inertia, and the stronger the vehicle's forward tendency, when the vehicle's overall mass increases, the coverage of the small and medium braking ranges can be increased. This allows the main vehicle motor to participate in the overall vehicle braking in vehicles with larger masses, further improving the energy recovery efficiency of braking and avoiding dangers such as vehicle skidding or tail swing.

[0064] Furthermore, when vehicles have the same load rating, the target deceleration is greater within the braking range with higher braking intensity. Thus, when the brake pedal is in the braking range with higher braking intensity, the vehicle can be braked quickly. The driver can adjust the braking rate of the vehicle by controlling the opening of the brake pedal, and the vehicle's overall controller can also obtain the driver's braking intention through the opening of the brake pedal. For example, the driver can brake the vehicle quickly to ensure driving safety or brake the vehicle slowly to ensure braking comfort, thereby meeting the driver's braking needs and improving driving comfort.

[0065] Furthermore, multiple load levels include no-load, half-load, and full-load levels;

[0066] As shown in the table below:

[0067]

[0068] When the brake pedal is in the low braking range:

[0069] If the vehicle is in an unloaded state, the target deceleration is less than 0.05g;

[0070] If the vehicle is at half load level, the target deceleration is less than 0.1g;

[0071] If the vehicle is at full load, the target deceleration is less than 0.15g;

[0072] Where g is the acceleration caused by gravity on a freely falling object, known as gravitational acceleration, usually taken as g = 9.80 m / s². 2 .

[0073] In this way, when the brake pedal is in the small braking range, the vehicle will have a target deceleration upper limit at different load levels, avoiding excessive target deceleration of the vehicle. This also avoids excessive target deceleration of the vehicle when the braking force of the main vehicle motor accounts for a large proportion of the total vehicle braking force, and prevents the main vehicle rear axle from locking up in the small braking range, which could lead to tail swing or sideslip, thus improving braking safety.

[0074] Moreover, as the vehicle's load level increases, the small braking range of the brake pedal can cover more target decelerations, thereby increasing the proportion of braking force from the main motor under larger target decelerations, further improving the energy recovery efficiency of vehicle braking, and reducing overall vehicle power consumption.

[0075] Additionally, when the brake pedal is in the medium braking range:

[0076] If the vehicle is in an unloaded state, the target deceleration is greater than 0.05g and less than 0.2g;

[0077] If the vehicle is at half load level, the target deceleration is less than 0.1g and less than 0.25g;

[0078] If the vehicle is at full load, the target deceleration is less than 0.15g and less than 0.3g;

[0079] This avoids the main vehicle motor's braking force accounting for an excessively large proportion of the vehicle's total braking force when the target deceleration is large. It allows the trailer air brake to participate in the vehicle's braking when the target deceleration increases. The main vehicle motor braking and the trailer air brake work together to brake the vehicle, thereby improving the coordination of the vehicle's braking, preventing the main vehicle's rear axle from locking up, and thus avoiding phenomena such as vehicle skidding or tail swing, resulting in higher braking safety.

[0080] In addition, when the brake pedal is in the maximum braking range:

[0081] If the vehicle is in an unloaded state, the target deceleration is greater than 0.2g;

[0082] If the vehicle is at half load level, the target deceleration is less than 0.25g;

[0083] If the vehicle is at full load, the target deceleration is less than 0.3g;

[0084] In other words, when the vehicle is unloaded and the target deceleration is greater than 0.2g, the main vehicle motor will no longer participate in braking. When the vehicle is half-loaded and the target deceleration is less than 0.25g, the main vehicle motor will no longer participate in braking. When the vehicle is fully loaded and the target deceleration is less than 0.3g, the main vehicle motor will no longer participate in braking. In this way, when the brake pedal is in the large braking range and the vehicle's target deceleration is large, braking can be carried out entirely by the trailer air brake, and the wheels of the main vehicle will not be braked. This more effectively avoids wheel lock-up of the main vehicle and further avoids dangers such as wheel tail swing or sideslip.

[0085] In some specific embodiments of the present invention, such as Figure 2 As shown, the vehicle control methods include:

[0086] Obtain the overall vehicle status;

[0087] Determine whether the overall vehicle condition meets the conditions for regenerative braking;

[0088] If so, control the main vehicle motor to output braking force;

[0089] If not, the main vehicle motor will stop outputting braking force.

[0090] In this way, the vehicle can recover energy from the braking force output by the main motor when the vehicle's overall condition meets the conditions for regenerative braking, and will not recover braking energy from the main motor when the vehicle's overall condition does not meet the conditions for regenerative braking, thereby improving the energy recovery efficiency of the vehicle's electric braking.

[0091] Furthermore, such as Figure 2 As shown, determining whether the vehicle's overall condition meets the regenerative braking conditions includes:

[0092] Get vehicle speed and remaining battery charge;

[0093] Determine whether the vehicle speed is greater than the preset speed and whether the remaining battery charge is less than the preset charge.

[0094] If so, obtain the vehicle's yaw rate and the road surface adhesion coefficient;

[0095] Determine whether the yaw rate is not greater than the preset yaw rate, or whether the road surface adhesion coefficient is not less than the preset coefficient;

[0096] If so, then control the main vehicle motor to output braking force.

[0097] In other words, if the braking force of the main vehicle motor is to be recovered, the main vehicle motor needs to output braking force to participate in braking. That is to say, the yaw rate of the vehicle must not be greater than the preset yaw rate, or the road surface adhesion coefficient must not be less than the preset coefficient, and the vehicle speed must be greater than the preset vehicle speed and the remaining charge of the battery pack must be less than the preset charge.

[0098] This ensures the braking safety of the vehicle's main motor during braking, preventing the vehicle from skidding. It also allows for a lower remaining charge in the battery pack, facilitating energy recovery from the main motor's braking force to continue charging the battery pack. This prevents the battery pack from being overcharged and in a floating charging state, and avoids excessive braking feedback when regenerative braking is performed at low speeds, thus improving the vehicle's braking comfort.

[0099] It should be noted that the vehicle's yaw rate must not exceed a preset yaw rate, and the road surface adhesion coefficient must not be less than a preset coefficient. If either of these two factors is satisfied, it means that the main vehicle motor can output braking force. For example, if the vehicle's yaw rate is not greater than the preset yaw rate and the road surface adhesion coefficient is not less than the preset coefficient, the vehicle's yaw rate is relatively small and the road surface adhesion coefficient is relatively large, making it less likely for the vehicle to sideslip or fishtail. Alternatively, if the vehicle's yaw rate is not greater than the preset yaw rate and the road surface adhesion coefficient is less than the preset coefficient, although the road surface adhesion coefficient is relatively small, the vehicle's yaw rate is still relatively small, and the vehicle will not sideslip. Or, if the vehicle's yaw rate is greater than the preset yaw rate and the road surface adhesion coefficient is not less than the preset coefficient, although the vehicle's yaw rate is relatively large, the road surface adhesion coefficient is relatively large, the wheel grip is relatively large, and the vehicle can rely on wheel grip to adjust its posture and avoid sideslip.

[0100] Furthermore, the preset vehicle speed is no less than 10 km / h, and the preset battery charge is no more than 90%. This avoids regenerative braking when the vehicle speed is too low, thereby preventing brake feedback during low-speed driving, improving braking comfort, and also preventing excessive remaining charge in the battery pack, which could lead to float charging and protect the battery pack.

[0101] In addition, the preset yaw rate is no more than 6° / second. This allows the vehicle's yaw rate to be controlled at a relatively low speed, resulting in a smaller yaw angle and thus preventing the vehicle from skidding or tail-wagging.

[0102] Furthermore, the preset coefficient is adjusted according to the vehicle speed. For example, the higher the vehicle speed, the larger the preset coefficient can be, so that the requirements for the road surface adhesion coefficient are higher when the vehicle speed is higher. When the vehicle speed is higher, the road surface adhesion coefficient needs to be larger so that the main motor can provide braking force. This can prevent the vehicle from skidding or fishtailing due to the road surface adhesion coefficient being too small, and further improve the braking safety of the vehicle.

[0103] Other configurations and operations of the vehicle control method according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0104] In the description of this specification, references to terms such as "specific embodiment" or "specific example" refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0105] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for controlling a vehicle, characterized in that, include: Obtain the brake pedal opening; If the opening of the brake pedal is within the allowable range of deceleration variation, the braking force of the main vehicle motor is adjusted according to the opening of the brake pedal, and the allowable range of deceleration variation includes multiple braking intervals. The proportion of the braking force of the main vehicle motor in the total vehicle braking force decreases as the overall braking interval increases. Among them, the multiple braking ranges include small braking range, medium braking range and large braking range; If the brake pedal is in the small braking range, then obtain the vehicle mass m, target deceleration a, and actual deceleration a0, and the braking force F of the main vehicle motor = ma + F0. F0 is the braking force correction value, which is adjusted according to the target deceleration and the actual deceleration, K P K I and K D To perform calibration during real vehicle testing; If the brake pedal is in the medium braking range, the vehicle speed is obtained, and the braking force of the main vehicle motor is adjusted according to the opening of the brake pedal and the vehicle speed. If the brake pedal is in the maximum braking range, the main vehicle motor stops outputting braking force.

2. The vehicle control method according to claim 1, characterized in that, If the brake pedal is in the middle braking range, activate the trailer air brake and adjust the braking force ratio of the main vehicle and the trailer to meet the rear axle adhesion utilization coefficient. Determine whether the braking force of the main vehicle motor meets the braking force of the main vehicle; If so, the main vehicle motor provides braking force to the main vehicle; If not, activate the air brake on the front axle of the main vehicle.

3. The vehicle control method according to claim 1, characterized in that, If the brake pedal is in the small braking range, then it is determined whether the braking force of the main vehicle motor meets the braking force required for the target deceleration. If so, the main vehicle motor alone provides braking force for the vehicle; If not, activate the air brake on the front axle of the main vehicle.

4. The vehicle control method according to claim 1, characterized in that, The vehicle has multiple load levels. Within the same braking range, the threshold value of the target deceleration increases with the increase of the load level, and within the same load level, the target deceleration increases with the increase of the braking range.

5. The vehicle control method according to claim 4, characterized in that, The load levels include no-load, half-load, and full-load levels; When the brake pedal is in the small braking range: If the vehicle is in the unloaded state, the target deceleration is less than 0.05g; If the vehicle is at the half-load level, the target deceleration is less than 0.1g; If the vehicle is at the full load level, the target deceleration is less than 0.15g; When the brake pedal is in the middle braking range: If the vehicle is in the unloaded state, the target deceleration is greater than 0.05g and less than 0.2g; If the vehicle is at the half-load level, the target deceleration is less than 0.1g and less than 0.25g; If the vehicle is at the full load level, the target deceleration is less than 0.15g and less than 0.3g; When the brake pedal is in the maximum braking range: If the vehicle is in the unloaded state, the target deceleration is greater than 0.2g; If the vehicle is at the half-load level, the target deceleration is less than 0.25g; If the vehicle is at the full load level, the target deceleration is less than 0.3g; Where g is the acceleration due to gravity.

6. The vehicle control method according to any one of claims 1-5, characterized in that, The allowable range of the opening degree is 8% to 75% of the maximum opening degree of the brake pedal.

7. The vehicle control method according to any one of claims 1-5, characterized in that, include: Obtain the overall vehicle status; Determine whether the vehicle's overall condition meets the regenerative braking conditions; If so, then control the main vehicle motor to output braking force; If not, then control the main vehicle motor to stop outputting braking force.

8. The vehicle control method according to claim 7, characterized in that, The determination of whether the vehicle state meets the regenerative braking conditions includes: Get vehicle speed and remaining battery charge; Determine whether the vehicle speed is greater than a preset vehicle speed and whether the remaining charge of the battery pack is less than a preset charge. If so, obtain the yaw rate and road adhesion coefficient of the vehicle; Determine whether the yaw rate is not greater than a preset yaw rate, or whether the road surface adhesion coefficient is not less than a preset coefficient; If so, then control the main vehicle motor to output braking force.

9. The vehicle control method according to claim 8, characterized in that, The preset vehicle speed is not less than 10km / h, the preset battery level is not greater than 90%, the preset yaw rate is not greater than 6° / second, and the preset coefficient is adjusted according to the vehicle speed.

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