Vehicle control method and device, vehicle and readable storage medium

Abstract

The invention provides a vehicle control method and device, a vehicle and a readable storage medium, the method is applied to the technical field of vehicles, and the method comprises the steps that when it is monitored that a brake pedal of the vehicle is stepped down, auxiliary braking force is determined; and according to the target pitch angle of the vehicle in the current period, the distribution proportion of the auxiliary braking force between the front axle motor and the rear axle motor is determined. And then according to the auxiliary braking force and the distribution proportion, first braking force provided by the front axle motor to the vehicle in the next adjacent period and second braking force provided by the rear axle motor to the vehicle in the next period are determined. And in the next period, the front axle motor is controlled to output corresponding braking force according to the first braking force, and the rear axle motor is controlled to output corresponding braking force according to the second braking force. According to the method, the distribution proportion of the auxiliary braking force between the front axle motor and the rear axle motor can be adjusted according to the target pitch angle of the vehicle, so that the change of the pitch angle is reduced while the braking distance of the vehicle is guaranteed.

Description

Technical Field

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

[0002] When the vehicle is braking, if the braking force is large, the pitch angle of the vehicle may be large. When the pitch angle is large, the driver and passengers may feel a strong shaking, which affects the riding comfort of the driver and passengers.

[0003] In the related art, in order to avoid a large pitch angle of the vehicle, one method is to reduce the pitch angle of the vehicle by reducing the braking force of the front and rear wheels of the vehicle when the braking force is large, thereby reducing the shaking feeling of the driver and passengers and improving the riding comfort of the driver and passengers. However, reducing the braking force may increase the braking distance of the vehicle and increase the risk of collision of the vehicle. Therefore, this method is usually not adopted. Therefore, there is an urgent need for a vehicle control method that can ensure the braking distance of the vehicle and reduce the pitch angle at the same time. Summary of the invention

[0004] The present application provides a vehicle control method, device, vehicle and readable storage medium, which can reduce the pitch angle change rate while ensuring the braking distance of the vehicle.

[0005] In a first aspect, a vehicle control method is provided, the method comprising:

[0006] When it is detected that the brake pedal of the vehicle is stepped on, the auxiliary braking force is determined; wherein the auxiliary braking force is the total braking force provided to the vehicle by the front axle motor and the rear axle motor in the vehicle;

[0007] Determining the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to the target pitch angle of the vehicle in the current cycle;

[0008] Determining, according to the auxiliary braking force and the distribution ratio, a first braking force provided by the front axle motor to the vehicle in a next adjacent cycle, and a second braking force provided by the rear axle motor to the vehicle in a next cycle;

[0009] In the next cycle, the front axle motor is controlled to output a corresponding braking force according to the first braking force, and the rear axle motor is controlled to output a corresponding braking force according to the second braking force, so as to reduce the pitch angle of the vehicle.

[0010] In an embodiment of the present application, when the brake pedal of the vehicle is stepped on, the electronic control unit can determine the auxiliary braking force that can be provided to the vehicle by the front axle motor and the rear axle motor, and then periodically detect the pitch angle of the vehicle. In each cycle, after determining the target pitch angle of the vehicle in the current cycle, the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor is determined according to the target pitch angle, wherein the larger the target pitch angle, the greater the proportion of the braking force output by the rear axle motor in the auxiliary braking force. And in the next cycle, the front axle motor is controlled to output the corresponding first braking force, and the rear axle motor is controlled to output the corresponding second braking force. The distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor is dynamically adjusted by the target pitch angle, so that the pitch angle of the vehicle can be reduced and the comfort of the vehicle during braking can be improved.

[0011] In combination with the first aspect, in some possible implementations, before determining the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to the target pitch angle of the vehicle in the current cycle, the method further includes:

[0012] determining a predicted pitch angle of the vehicle during the current cycle;

[0013] When the braking duration is greater than the preset duration, the predicted pitch angle is reduced by a target amplitude according to the braking duration to obtain a target pitch angle; wherein the braking duration is the duration from the moment the brake pedal is pressed to the current moment, and the target amplitude is positively correlated with the braking duration.

[0014] In the embodiment of the present application, if the braking time is longer than the preset time, it means that the vehicle has not stopped for a long time, and the predicted pitch angle will continue to accumulate with the increase of the braking time, which will affect the calculation accuracy of the predicted pitch angle. Therefore, the electronic control unit reduces the predicted pitch angle by the target amplitude according to the braking time, which can ensure the calculation accuracy of the predicted pitch angle to a certain extent.

[0015] In conjunction with the first aspect, in some possible implementations, reducing the predicted pitch angle by a target amplitude according to the braking duration to obtain a target pitch angle includes:

[0016] Determine the time difference between the braking duration and the preset duration;

[0017] Determine the target amplitude according to the time difference; wherein the target amplitude is positively correlated with the time difference;

[0018] The predicted pitch angle is reduced by the target amplitude to obtain the target pitch angle.

[0019] In this embodiment, since the target amplitude is positively correlated with the time difference, the target amplitude is determined according to the time difference between the braking duration and the preset duration, and the predicted pitch angle can be reduced by the target amplitude, which can further ensure the calculation accuracy of the predicted pitch angle.

[0020] In conjunction with the first aspect, in some possible implementations, determining a predicted pitch angle of the vehicle in a current cycle includes:

[0021] Get the cumulative pitch angle of the vehicle before the current cycle;

[0022] The predicted pitch angle is determined according to the pitch angle change and the accumulated pitch angle of the vehicle in the current cycle.

[0023] In the embodiment of the present application, by combining the accumulated pitch angle before the current cycle and the pitch angle change in the current cycle, the electronic control unit can more accurately predict the pitch angle of the vehicle in the current cycle.

[0024] In combination with the first aspect, in some possible implementations, before determining the predicted pitch angle according to the pitch angle change amount and the accumulated pitch angle of the vehicle in the current cycle, the method further includes:

[0025] Acquire dynamic performance parameters of the vehicle and the acceleration of the vehicle in an adjacent previous cycle; wherein the dynamic performance parameters are related to the pitch angle of the vehicle;

[0026] The pitch angle change is determined based on the dynamic performance parameters, acceleration and accumulated pitch angle.

[0027] In the embodiment of the present application, by acquiring the dynamic performance parameters and acceleration related to the pitch angle of the vehicle, the state of the vehicle during braking can be obtained more accurately, which is conducive to more accurate calculation of the pitch angle change and improved accuracy of the predicted pitch angle.

[0028] In combination with the first aspect, in some possible implementations, when it is detected that the brake pedal of the vehicle is stepped on, determining the auxiliary braking force includes:

[0029] When it is detected that the brake pedal is depressed, determining the total pedal opening of the brake pedal and the rate of change of the opening when the brake pedal is depressed;

[0030] If the total pedal opening is greater than a preset opening and the opening change rate is less than a preset rate, the auxiliary braking force is determined.

[0031] In the embodiment of the present application, if the total pedal opening is greater than the preset opening and the opening change rate is less than the preset rate, it indicates that the vehicle is not in emergency braking. When it is determined that the vehicle is not in emergency braking, the electronic control unit determines the auxiliary braking force and dynamically adjusts the auxiliary braking force of the front and rear axles to reduce the change rate of the pitch angle, thereby improving the comfort of the driver and passengers. On the contrary, if the vehicle is in emergency braking, the hydraulic system is directly controlled to output the total braking force to improve the safety of the vehicle.

[0032] In combination with the first aspect, in some possible implementations, if the total pedal opening is greater than a preset opening and the opening change rate is less than a preset rate, determining the auxiliary braking force includes:

[0033] If the total pedal opening is greater than a preset opening, and the opening change rate is less than a preset rate, then determining the current steering amplitude and current speed of the vehicle;

[0034] If the steering amplitude is smaller than the preset amplitude and the speed is greater than the preset speed, the auxiliary braking force is determined.

[0035] In the embodiment of the present application, if the steering amplitude is less than the preset amplitude and the speed is greater than the preset speed, it indicates that the vehicle is braking while driving in a straight line at high speed without emergency braking. If the vehicle is braking while driving in a straight line at high speed, the electronic control unit determines the auxiliary braking force and reduces the rate of change of the pitch angle by dynamically adjusting the auxiliary braking force of the front and rear axles, thereby further improving the comfort of the driver and passengers. On the contrary, if the vehicle is braking with a large steering amplitude, the electronic control unit directly controls the hydraulic system to output the total braking force to further improve the safety of the vehicle.

[0036] In a second aspect, a vehicle control device is provided, the device comprising:

[0037] A first determination module is used to determine the auxiliary braking force when it is detected that the brake pedal of the vehicle is stepped on; wherein the auxiliary braking force is the braking force provided to the vehicle by the front axle motor and the rear axle motor in the vehicle;

[0038] A second determination module is used to determine the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to the target pitch angle of the vehicle in the current cycle;

[0039] a third determining module, configured to determine, according to the auxiliary braking force and the distribution ratio, a first braking force provided by the front axle motor to the vehicle in a next adjacent cycle, and a second braking force provided by the rear axle motor to the vehicle in a next cycle;

[0040] The control module is used to control the front axle motor to output a corresponding braking force according to the first braking force, and to control the rear axle motor to output a corresponding braking force according to the second braking force in the next cycle, so as to reduce the pitch angle of the vehicle.

[0041] In a third aspect, a vehicle is provided, comprising a memory for storing executable program code;

[0042] A processor is used to call and run executable program code from a memory so that the vehicle executes the method in any possible implementation of the first aspect above.

[0043] In a fourth aspect, an executable program code product is provided, the executable program code product comprising: an executable program code, when the executable program code is run on a computer, the computer executes the method in any possible implementation of the first aspect above.

[0044] In a fifth aspect, a readable storage medium is provided, which stores executable program code. When the executable program code runs on a computer, the computer executes the method in any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flow chart of the steps of a vehicle control method provided by an embodiment of the present application;

[0046] Figure 2 is a structural schematic diagram of a vehicle control device provided in an embodiment of the present application;

[0047] Figure 3 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] 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.

[0049] 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.

[0050] At present, when a vehicle is braking, if the braking force is large, the center of gravity of the vehicle will shift greatly, and the pitch angle of the vehicle may be relatively large. When the pitch angle is large, the driver and passengers may feel a strong shaking feeling, which affects the riding comfort of the driver and passengers.

[0051] In the related art, in order to avoid a large pitch angle of the vehicle, one method is to reduce the pitch angle of the vehicle by reducing the braking force of the front and rear wheels of the vehicle when the braking force is large, thereby reducing the shaking feeling of the driver and passengers and improving the riding comfort of the driver and passengers. However, reducing the braking force may increase the braking distance of the vehicle and increase the risk of collision of the vehicle.

[0052] In order to solve the above technical problems, a vehicle control method provided by an embodiment of the present application can be applied in a vehicle equipped with a front axle motor and a rear axle motor, and is executed by an electronic control unit (ECU) in the vehicle for controlling the braking system. A power battery is installed in the vehicle. When the front axle motor outputs a positive torque to the front wheel, electric energy is obtained from the power battery to provide a driving force for the front wheel to drive the front wheel to rotate; when the front axle motor outputs a reverse torque to the front wheel, the front axle motor generates electricity as a generator, and while providing a braking force to the front wheel, the power battery can also be charged. Similarly, when the rear axle motor outputs a positive torque to the rear wheel, it obtains electric energy from the power battery to provide a driving force for the rear wheel to drive the rear wheel to rotate; when the rear axle motor outputs a reverse torque to the rear wheel, the rear axle motor generates electricity as a generator, and while providing a braking force to the rear wheel, the power battery can also be charged.

[0053] In this method, when the brake pedal of the vehicle is pressed, the electronic control unit first determines the braking force (hereinafter referred to as the auxiliary braking force) that can be provided to the vehicle by the front axle motor and the rear axle motor, and then periodically detects the pitch angle of the vehicle. In each cycle, after determining the target pitch angle of the vehicle in the current cycle, the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor is determined according to the target pitch angle, and in the next cycle, the front axle motor is controlled to output the corresponding first braking force, and the rear axle motor is controlled to output the corresponding second braking force. The distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor is dynamically adjusted according to the target pitch angle, thereby reducing the pitch angle of the vehicle and improving the comfort of the vehicle during braking.

[0054] See also Figure 1 , Figure 1 is a flow chart of the steps of a vehicle control method provided by an embodiment of the present application. The execution subject of the method may be an electronic control unit in a vehicle, such as Figure 1 As shown, the method may include the following steps.

[0055] S101, when it is detected that the brake pedal of the vehicle is depressed, determining the auxiliary braking force.

[0056] The auxiliary braking force is the braking force currently provided to the vehicle by the front axle motor and the rear axle motor in the vehicle.

[0057] When the electronic control unit detects that the vehicle's brake pedal is pressed, the brake pedal opening can be determined. The brake pedal opening refers to the change in the brake pedal when the driver presses the brake pedal, which can be expressed as a percentage. For example, when the brake pedal is halfway pressed, the brake pedal opening is 50%; when the brake pedal is not pressed, the brake pedal opening is 0%.

[0058] In this embodiment, when the electronic control unit detects that the brake pedal of the vehicle is stepped on, it can determine the opening of the brake pedal, and determine the first total braking force currently required by the vehicle according to the opening of the brake pedal. At the same time, the electronic control unit can determine the second total braking force that can be provided by the front axle motor and / or the rear axle motor at the current moment according to the amount of electricity that can be charged into the power battery. If the second total braking force is less than or equal to the first total braking force, the second total braking force is determined to be an auxiliary braking force, and if the second total braking force is greater than the first total braking force, the first total braking force is determined to be an auxiliary braking force.

[0059] For example, during vehicle driving, after the electronic control unit detects that the brake pedal of the vehicle is stepped on, it determines that the opening of the brake pedal is 40%, and the first total braking force corresponding to the opening of 40% is 100 Newtons (N). At the same time, according to the amount of electricity that can be charged in the power battery, it is determined that the second total braking force that can be provided by the front axle motor and / or the rear axle motor at the current moment is 60N. At this time, the auxiliary braking force can be determined to be 60N. For another example, when the first total braking force is determined to be 100N and the second total braking force is 120N, the auxiliary braking force can be determined to be 100N.

[0060] When the second total braking force is less than the first total braking force, the remaining braking force can be provided by the braking system in the vehicle. For example, when the first total braking force is determined to be 100N and the second total braking force is 60N, the auxiliary braking force can be determined to be 60N, and it can be determined that the braking system needs to provide 40N of braking force to the vehicle at the current moment.

[0061] S102, determining a distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to a target pitch angle of the vehicle in a current cycle.

[0062] The target pitch angle in the current cycle refers to the pitch angle of the vehicle from the moment the brake pedal is pressed to the current moment. The distribution ratio refers to the proportion of the braking force provided by the front axle motor and the braking force provided by the rear axle motor in the auxiliary braking force in the next cycle.

[0063] Exemplarily, after the brake pedal is stepped on, the electronic control unit can detect the pitch angle change of the vehicle in each cycle in real time, accumulate the pitch angle change in each cycle, and obtain the target pitch angle of the vehicle in the current cycle. For example, if the duration of each cycle is 10 milliseconds, the timing starts when the brake pedal is stepped on, and the electronic control unit obtains the pitch angle of the vehicle in the first 10 milliseconds when the timing duration is 10 milliseconds, and obtains the pitch angle change in the first cycle, which is the target pitch angle in the first cycle. For the second cycle, the electronic control unit detects the pitch angle change of the vehicle from the 10th second to the 20th second when the timing duration is 20 milliseconds, and the pitch angle change is the pitch angle change in the second cycle. The target pitch angle of the first cycle and the pitch angle change of the second cycle are summed to obtain the target pitch angle in the second cycle. For the third cycle, the electronic control unit detects the pitch angle change of the vehicle from the 20th second to the 30th second when the timing duration is 30 milliseconds. The pitch angle change is the pitch angle change of the third cycle. The pitch angle change of the third cycle and the target pitch angle of the second cycle are summed to obtain the target pitch angle of the third cycle. By analogy, at the end of each cycle, the electronic control unit can obtain the target pitch angle of each cycle.

[0064] During the vehicle design phase, developers can pre-configure the initial distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor for the vehicle. For example, after the brake pedal is stepped on, the electronic control unit can obtain the initial distribution ratio and determine the first braking force provided by the front axle motor to the vehicle in the first cycle and the second braking force provided by the rear axle motor to the vehicle in the first cycle according to the initial distribution ratio.

[0065] In one embodiment, after the brake pedal is stepped on, the electronic control unit can obtain the initial distribution ratio, and determine the first braking force provided by the front axle motor to the vehicle in the first cycle and the second braking force provided by the rear axle motor to the vehicle in the first cycle according to the initial distribution ratio. After determining the target pitch angle of the vehicle in the current cycle, the electronic control unit can determine the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor in the next cycle according to the actual difference between the target pitch angle in the current cycle and the preset pitch angle. Exemplarily, during the driving process of the vehicle, the electronic control unit can determine the target pitch angle of the vehicle in the current cycle, and then calculate the difference between the target pitch angle in the current cycle and the preset pitch angle, and input the difference into a pre-designed proportional-integral-derivative controller (Proportional-Integral-Derivative Controller, PID controller) to obtain the proportional coefficient output by the PID controller, and determine the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to the proportional coefficient.

[0066] For example, the proportional coefficient output by the PID controller may be a percentage, corresponding to the proportion of the braking force output by the front axle motor or the rear axle motor in the auxiliary braking force. According to the proportional coefficient, the proportion of the front axle motor in the auxiliary braking force can be determined, and the proportion of the braking force output by the rear axle motor in the auxiliary braking force can be determined. For example, when the proportional coefficient is the proportion of the braking force output by the front axle motor in the auxiliary braking force, if the preset pitch angle is 0 degrees, the electronic control unit determines that the auxiliary braking force of the vehicle is 60N, and after the target pitch angle in the current cycle is 5 degrees, it can calculate that the difference between the target pitch angle of 5 degrees and the preset pitch angle of 0 degrees is 5 degrees. Afterwards, the electronic control unit can input the difference into the PID controller, and the PID controller outputs the proportional coefficient based on the difference, the proportional coefficient, integral coefficient, differential coefficient, etc. in the PID controller. If the output proportional coefficient is 0.4, then it is determined that the proportion of the braking force output by the front axle motor in the auxiliary braking force is 40%, and the proportion of the braking force output by the rear axle motor in the auxiliary braking force can be determined to be 60%. If the auxiliary braking force is 100N, it can be determined that the braking force output by the front axle motor in the next cycle is 40N, and the braking force output by the rear axle motor is 60N.

[0067] It should be noted that the target pitch angle in the current cycle is positively correlated with the proportion of the braking force output by the rear axle motor in the auxiliary braking force, that is, the larger the target pitch angle, the greater the proportion of the braking force output by the rear axle motor in the auxiliary braking force.

[0068] S103, determining a first braking force provided by the front axle motor to the vehicle in a next adjacent cycle and a second braking force provided by the rear axle motor to the vehicle in a next cycle according to the auxiliary braking force and the distribution ratio.

[0069] S104, in the next cycle, the front axle motor is controlled to output a corresponding braking force according to the first braking force, and the rear axle motor is controlled to output a corresponding braking force according to the second braking force, so as to reduce the pitch angle of the vehicle.

[0070] Among them, the first braking force refers to the electric braking force output by the front axle motor; the second braking force refers to the electric braking force output by the rear axle motor.

[0071] In one embodiment, after determining the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor, the electronic control unit can determine the first braking force provided by the front axle motor to the vehicle in the next adjacent cycle and the second braking force provided by the rear axle motor to the vehicle in the next cycle according to the distribution ratio and the auxiliary braking force. Further, in the next cycle, the electronic control unit controls the rear wheel motor to output the corresponding second braking force and controls the front wheel motor to output the corresponding first braking force.

[0072] For example, during vehicle driving, after determining that the auxiliary braking force of the vehicle is 60N, the first total braking force required by the vehicle is 50N, and the braking force output by the front axle motor accounts for 40% of the auxiliary braking force, and correspondingly determining that the braking force output by the rear axle motor accounts for 60% of the auxiliary braking force, the electronic control unit can calculate the first braking force output by the front axle motor in the next cycle as 24N based on the auxiliary braking force and the distribution ratio. At the same time, the second braking force output by the rear axle motor in the next cycle can be calculated as 36N based on the auxiliary braking force and the distribution ratio.

[0073] In another exemplary embodiment, during the driving process of the vehicle, after determining that the auxiliary braking force of the vehicle is 60N, the first total braking force required by the vehicle is 100N, and the braking force output by the front axle motor accounts for 40% of the auxiliary braking force, the electronic control unit can determine that the braking force output by the rear axle motor accounts for 60% of the auxiliary braking force, and calculate the first braking force output by the front axle motor in the next cycle to be 24N based on the auxiliary braking force and the distribution ratio. At the same time, the second braking force output by the rear axle motor in the next cycle can be calculated to be 36N based on the auxiliary braking force and the distribution ratio. Among them, the electronic control unit determines that the auxiliary braking force is less than the first total braking force, and determines that the braking system needs to provide 40N of braking force to the vehicle based on the difference between the first total braking force and the auxiliary braking force of the vehicle. Therefore, in the next cycle, the electronic control unit can control the rear axle motor to output the corresponding second braking force of 36N, control the front axle motor to output the corresponding first braking force of 24N, and control the braking system to output the corresponding braking force of 40N.

[0074] In an embodiment of the present application, when the brake pedal of the vehicle is stepped on, the electronic control unit can determine the auxiliary braking force that can be provided to the vehicle by the front axle motor and the rear axle motor, and then periodically detect the pitch angle of the vehicle. In each cycle, after determining the target pitch angle of the vehicle in the current cycle, the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor is determined according to the target pitch angle, wherein the larger the target pitch angle, the greater the proportion of the braking force output by the rear axle motor in the auxiliary braking force. And in the next cycle, the front axle motor is controlled to output the corresponding first braking force, and the rear axle motor is controlled to output the corresponding second braking force. The distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor is dynamically adjusted by the target pitch angle, so that the pitch angle of the vehicle can be reduced and the comfort of the vehicle during braking can be improved.

[0075] Furthermore, the electronic control unit can determine the braking force that the braking system needs to provide to the vehicle based on the auxiliary braking force of the vehicle and the first total braking force, so that the sum of the auxiliary braking force and the braking force of the braking system is equal to the first total braking force. Compared with the method of reducing the pitch angle of the vehicle by reducing the braking force of the front and rear axles of the vehicle, the present application reduces the rate of change of the pitch angle of the vehicle without reducing the total braking force of the vehicle, so the braking distance of the vehicle can be guaranteed, thereby improving the safety of the vehicle.

[0076] Optionally, before determining the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to the target pitch angle of the vehicle in the current cycle, the method further includes:

[0077] determining a predicted pitch angle of the vehicle during the current cycle;

[0078] When the braking duration is longer than a preset duration, the predicted pitch angle is reduced by a target amplitude according to the braking duration to obtain a target pitch angle.

[0079] The braking duration is the duration from the moment the brake pedal is pressed to the current moment, and the target amplitude is positively correlated with the braking duration. The predicted pitch angle in the current cycle refers to the initial cumulative pitch angle of the vehicle under the braking duration, that is, the sum of the pitch angle change of the vehicle in the current cycle and the cumulative pitch angle before the current cycle.

[0080] In this embodiment, after the brake pedal is stepped on, the electronic control unit can detect the pitch angle change of the vehicle in each cycle in real time, accumulate the pitch angle change in each cycle, obtain the cumulative pitch angle before the current cycle, and obtain the pitch angle change of the vehicle in the current cycle through the pitch angle sensor, calculate the sum of the pitch angle change of the vehicle in the current cycle and the cumulative pitch angle before the current cycle, and obtain the predicted pitch angle of the vehicle in the current cycle. Further, the electronic control unit obtains the time from the moment the brake pedal is stepped on to the current moment through the timer, and determines whether the braking time is greater than the preset time. In the case that the braking time is greater than the preset time, the electronic control unit determines the time difference between the braking time and the preset time; determines the target difference interval of the time difference according to the time difference, and determines the corresponding target amplitude according to the target difference interval; reduces the predicted pitch angle by the target amplitude according to the braking time to obtain the target pitch angle.

[0081] For example, the developer can configure a plurality of continuous difference intervals for the vehicle, each difference interval corresponding to a different target amplitude. After determining the time difference between the braking duration and the preset duration, the electronic control unit can determine the target amplitude corresponding to the target difference interval from the plurality of difference intervals, and reduce the predicted pitch angle by the target amplitude to obtain the target pitch angle.

[0082] For example, developers can pre-configure the first difference interval, the second difference interval, and the third difference interval. The first difference interval is a difference interval less than or equal to 5 milliseconds, the second difference interval is a difference interval greater than 5 milliseconds and less than or equal to 10 milliseconds, and the third difference interval is a difference interval greater than 10 milliseconds. At the same time, developers can configure different target amplitudes for each difference interval; the target amplitude corresponding to the first difference interval is 0.8 degrees; the target amplitude corresponding to the second difference interval is 1.0 degrees; and the target amplitude corresponding to the third difference interval is 1.5 degrees.

[0083] If the electronic control unit obtains through the timer that the duration from the moment the brake pedal is pressed to the current moment is 12 milliseconds, and the preset duration is 10 milliseconds, the electronic control unit determines that the time difference between the braking duration and the preset duration is 2 milliseconds; based on the time difference, the target difference interval in which the time difference is located is determined to be the first difference interval, and the target amplitude corresponding to the first difference interval is determined to be 0.8 degrees; based on the braking duration, the predicted pitch angle is reduced by 0.8 degrees to obtain the target pitch angle.

[0084] In the embodiment of the present application, the electronic control unit determines the predicted pitch angle of the vehicle in the current cycle; and when the braking duration is longer than the preset duration, the predicted pitch angle is reduced by a target amplitude according to the braking duration to obtain a target pitch angle. In the present embodiment, if the braking duration is longer than the preset duration, it indicates that the vehicle has not stopped for a long time, but the predicted pitch angle will continue to accumulate as the braking duration increases, which will affect the calculation accuracy of the predicted pitch angle. Therefore, the electronic control unit reduces the predicted pitch angle by a target amplitude according to the braking duration, which can guarantee the calculation accuracy of the predicted pitch angle to a certain extent.

[0085] Optionally, reducing the predicted pitch angle by a target amplitude according to the braking duration to obtain a target pitch angle includes:

[0086] Determine the time difference between the braking duration and the preset duration;

[0087] Determine the target amplitude according to the time difference; wherein the target amplitude is positively correlated with the time difference;

[0088] The predicted pitch angle is reduced by the target amplitude to obtain the target pitch angle.

[0089] In this embodiment, after the brake pedal is stepped on, the electronic control unit can detect the pitch angle change of the vehicle in each cycle in real time, accumulate the pitch angle change in each cycle, obtain the cumulative pitch angle before the current cycle, and obtain the pitch angle change of the vehicle in the current cycle through the pitch angle sensor, calculate the sum of the pitch angle change of the vehicle in the current cycle and the cumulative pitch angle before the current cycle, and obtain the predicted pitch angle of the vehicle in the current cycle. Further, the electronic control unit obtains the duration from the moment the brake pedal is stepped on to the current moment through the timer, and determines whether the braking duration is greater than the preset duration. In the case that the braking duration is greater than the preset duration, the electronic control unit determines the time difference between the braking duration and the preset duration; determines the target amplitude according to the time difference, and reduces the predicted pitch angle by the target amplitude to obtain the target pitch angle.

[0090] For example, the R&D personnel can determine the functional relationship between the time difference and the target amplitude in advance through experiments, in which the time difference is positively correlated with the target amplitude. For example, during the driving process of the vehicle, the electronic control unit obtains the pre-stored cumulative pitch angle of the vehicle before the current cycle of 7 degrees, and obtains the pitch angle change of the vehicle in the current cycle of 3 degrees through the pitch angle sensor, and calculates the predicted pitch angle in the current cycle as 10 degrees. The electronic control unit determines through the timer that the time from the brake pedal being stepped on to the current moment is 2.5 seconds, that is, the braking time is 2.5 seconds; assuming that the preset time is 2 seconds, the electronic control unit determines that the time difference between the braking time and the preset time is 0.5 seconds. Afterwards, the electronic control unit can substitute the time difference 0.5 into the predetermined functional relationship to obtain the target amplitude, and reduce the predicted pitch angle by the target amplitude to obtain the target pitch angle.

[0091] For another example, when the vehicle is driving, the electronic control unit obtains the pre-stored cumulative pitch angle of the vehicle before the current cycle of 7 degrees, and at the same time obtains the pitch angle change of the vehicle in the current cycle of 3 degrees through the pitch angle sensor, and calculates the predicted pitch angle in the current cycle as 10 degrees. The electronic control unit determines through the timer that the time from the brake pedal being stepped on to the current moment is 1.5 seconds, that is, the braking time is 1.5 seconds; assuming that the preset time is 2 seconds, the electronic control unit determines that the braking time is not greater than the preset time. At this time, the electronic control unit does not need to adjust the predicted pitch angle, and can directly use the predicted pitch angle as the target pitch angle.

[0092] In the embodiment of the present application, the electronic control unit determines the time difference between the braking duration and the preset duration; determines the target amplitude according to the time difference; wherein the target amplitude is positively correlated with the time difference; and reduces the predicted pitch angle by the target amplitude to obtain the target pitch angle. In the present embodiment, since the target amplitude is positively correlated with the time difference, the target amplitude is determined according to the time difference between the braking duration and the preset duration, and the predicted pitch angle can be reduced by the target amplitude, which can further ensure the calculation accuracy of the predicted pitch angle.

[0093] Optionally, determining a predicted pitch angle of the vehicle in a current cycle includes:

[0094] Get the cumulative pitch angle of the vehicle before the current cycle;

[0095] The predicted pitch angle is determined according to the pitch angle change and the accumulated pitch angle of the vehicle in the current cycle.

[0096] The cumulative pitch angle refers to the total pitch angle accumulated by the vehicle from the moment the brake pedal is stepped on to the current cycle. The pitch angle change refers to the change in the pitch angle of the vehicle in the current cycle.

[0097] In this embodiment, after the brake pedal is stepped on, the electronic control unit can detect the pitch angle change of the vehicle in each cycle in real time, accumulate the pitch angle change in each cycle, and obtain the cumulative pitch angle before the current cycle; at the same time, the pitch angle change of the vehicle in the current cycle is calculated. And according to the pitch angle change of the vehicle in the current cycle and the cumulative pitch angle, the predicted pitch angle is determined.

[0098] For example, the electronic control unit can obtain the pre-stored cumulative pitch angle of 7 degrees before the current cycle, and calculate the pitch angle change of the vehicle in the current cycle as 1 degree. The sum of the pitch angle change and the cumulative pitch angle of the vehicle in the current cycle is calculated to obtain a predicted pitch angle of 8 degrees.

[0099] Optionally, the calculation formula for the predicted pitch angle can be expressed as:

[0100] F T =F T-1 +dFdt×G (1)

[0101] Among them, F T represents the predicted pitch angle in the current cycle T; dFdt represents the rate of change of the vehicle's pitch angle at time t; G represents the duration of the current cycle T, which is a constant and can be obtained through experiments; F T-1 It represents the cumulative pitch angle before the current cycle T, that is, the target pitch angle in the T-1th cycle.

[0102] Of course, the calculation formula for predicting the pitch angle can also be expressed as other variations or equivalent formulas of the above formula (1).

[0103] In the embodiment of the present application, the electronic control unit obtains the cumulative pitch angle of the vehicle before the current cycle; and determines the predicted pitch angle according to the pitch angle change and the cumulative pitch angle of the vehicle in the current cycle. In the present embodiment, by combining the cumulative pitch angle before the current cycle and the pitch angle change in the current cycle, the electronic control unit can more accurately predict the pitch angle of the vehicle in the current cycle.

[0104] Optionally, before determining the predicted pitch angle according to the pitch angle change amount and the accumulated pitch angle of the vehicle in the current cycle, the method further includes:

[0105] The dynamic performance parameters of the vehicle and the acceleration of the vehicle in an adjacent previous cycle are obtained; and the pitch angle change is determined according to the dynamic performance parameters, the acceleration and the accumulated pitch angle.

[0106] Among them, the dynamic performance parameters are related to the pitch angle of the vehicle; the dynamic performance parameters may include but are not limited to vehicle weight, center of mass height, suspension equivalent stiffness and moment of inertia.

[0107] In this embodiment, the electronic control unit can obtain the vehicle weight, center of mass height, suspension equivalent stiffness and moment of inertia of the vehicle, and the acceleration of the vehicle in the previous cycle; then, the pitch angle change rate is determined according to the vehicle weight, center of mass height, suspension equivalent stiffness and moment of inertia, acceleration and accumulated pitch angle. Further, the pitch angle change amount is calculated according to the pitch angle change rate and the current cycle duration.

[0108] Exemplarily, when calculating the pitch angle change rate, the product of the vehicle weight, the vehicle acceleration and the center of mass height can be first calculated to obtain a first intermediate result; at the same time, the product of the suspension equivalent stiffness and the cumulative pitch angle before the current cycle T is calculated to obtain a second intermediate result. The difference between the first intermediate result and the second intermediate result is calculated to obtain a third intermediate result. Further, the ratio between the third intermediate result and the moment of inertia is calculated to obtain the pitch angle change rate.

[0109] Exemplarily, the calculation formula of the pitch angle change rate can be expressed as:

[0110] dFdt=(M×dV x dt×LK×F T-1 ) / J (2)

[0111] Where M represents the vehicle weight, that is, the total mass of the vehicle; dV xdt represents the differential value of vehicle speed, i.e., the acceleration of the vehicle; L represents the height of the center of mass, i.e., the height of the center of mass of the vehicle relative to the ground; K represents the equivalent stiffness of the suspension, i.e., the ability of the suspension to resist deformation; J represents the moment of inertia, i.e., the inertia of the vehicle when it rotates around the pitch axis.

[0112] Of course, the calculation formula for the pitch angle change rate can also be expressed as other variations or equivalent formulas of the above formula (2).

[0113] In the embodiment of the present application, the electronic control unit obtains the dynamic performance parameters of the vehicle and the acceleration of the vehicle in the previous adjacent cycle; and determines the pitch angle change amount according to the dynamic performance parameters, acceleration and accumulated pitch angle. Since different vehicles have different dynamic performance parameters, in the present embodiment, by obtaining the dynamic performance parameters and acceleration related to the pitch angle of the vehicle, it is beneficial to more accurately calculate the pitch angle change amount and improve the accuracy of the predicted pitch angle.

[0114] Optionally, the electronic control unit may limit the maximum and minimum values ​​of the pitch angle change rate, and when the absolute value of the pitch angle change rate is lower than a preset change threshold, the electronic control unit may set the pitch angle change rate to 0. If the pitch angle change rate is greater than a preset maximum threshold, the electronic control unit may use the maximum threshold as the pitch angle change rate; if the pitch angle change rate is less than a preset minimum threshold, the electronic control unit may use the minimum threshold as the pitch angle change rate.

[0115] For example, in actual applications, R&D personnel can pre-set the change threshold, maximum threshold and minimum threshold. If the preset maximum threshold is 10 degrees / second, the minimum threshold is -10 degrees / second, and the preset change threshold is 1 degree / second, when the electronic control unit determines that the absolute value of the pitch angle change rate is 0.5 degrees / second (lower than the change threshold of 1 degree / second), the electronic control unit will set the pitch angle change rate to 0 degrees / second. If the electronic control unit determines that the pitch angle change rate is 12 degrees / second (exceeding the maximum threshold of 10 degrees / second), the electronic control unit will adjust the pitch angle change rate to 10 degrees / second. On the contrary, if the electronic control unit determines that the pitch angle change rate is -12 degrees / second (lower than the minimum threshold of -10 degrees / second), the electronic control unit will adjust the pitch angle change rate to -10 degrees / second.

[0116] It should be noted that the maximum threshold and the minimum threshold can be set accordingly according to the type of vehicle, and there is no limitation on this.

[0117] In the embodiment of the present application, the electronic control unit can ensure that the pitch angle change rate is within a reasonable range by limiting the range of the pitch angle change rate. At the same time, different maximum thresholds and minimum thresholds are determined based on different vehicle types, which is conducive to matching the calculation result of the pitch angle change rate with the actual vehicle type, so that the pitch angle change rate can be calculated more accurately.

[0118] Optionally, when it is detected that the brake pedal of the vehicle is depressed, determining the auxiliary braking force includes:

[0119] When it is detected that the brake pedal is depressed, determining the total pedal opening of the brake pedal and the rate of change of the opening when the brake pedal is depressed;

[0120] If the total pedal opening is greater than a preset opening and the opening change rate is less than a preset rate, the auxiliary braking force is determined.

[0121] The total pedal opening refers to the change in the brake pedal from the completely unpressed state to the current pressed position. The opening change rate refers to the change in the brake pedal opening per unit time.

[0122] In this embodiment, when the vehicle is running and the brake pedal is detected to be stepped on, the electronic control unit obtains the total pedal opening of the brake pedal and the opening change rate when the brake pedal is stepped on through the vehicle bus. The total pedal opening is compared with the preset opening, and the opening change rate is compared with the preset rate. If the total pedal opening is greater than the preset opening, and the opening change rate is less than the preset rate, the electronic control unit can determine the auxiliary braking force according to the total pedal opening.

[0123] Exemplarily, the R&D personnel can pre-set the preset opening and preset rate for the vehicle. For example, the R&D personnel pre-set the preset opening of the vehicle to 60% and the preset rate to 10 degrees per second. During the operation of the vehicle, it is detected that the brake pedal is stepped on, and the electronic control unit obtains the total pedal opening of the brake pedal of 80% and the opening change rate of 5 degrees per second when the brake pedal is stepped on through the vehicle bus. The electronic control unit compares the total pedal opening with the preset opening, and compares the opening change rate with the preset rate, and determines that the total pedal opening is greater than the preset opening, and the opening change rate is less than the preset rate. Afterwards, the electronic control unit can determine the auxiliary braking force according to the total opening of the pedal.

[0124] For another example, when the brake pedal is detected to be stepped on, the electronic control unit obtains the total pedal opening of 50% of the brake pedal and the opening change rate of 5 degrees per second when the brake pedal is stepped on through the vehicle bus. The electronic control unit compares the total pedal opening with the preset opening, and compares the opening change rate with the preset rate, and determines that the opening change rate is less than the preset rate, but the total pedal opening is not greater than the preset opening. After that, the electronic control unit does not need to determine the auxiliary braking force, and directly controls the braking system to output the first total braking force.

[0125] For another example, when the brake pedal is detected to be stepped on, the electronic control unit obtains the total pedal opening of 80% of the brake pedal and the opening change rate of 15 degrees per second when the brake pedal is stepped on through the vehicle bus. The electronic control unit compares the total pedal opening with the preset opening, and compares the opening change rate with the preset rate, and determines that the total pedal opening is greater than the preset opening, but the opening change rate is greater than the preset rate. Then the electronic control unit does not need to determine the auxiliary braking force, and directly controls the braking system to output the first total braking force.

[0126] In the embodiment of the present application, when the electronic control unit detects that the brake pedal is stepped on, it determines the total pedal opening of the brake pedal and the rate of change of the opening when the brake pedal is stepped on; when the total pedal opening is greater than the preset opening and the rate of change of the opening is less than the preset rate, the auxiliary braking force is determined. In this embodiment, if the total pedal opening is greater than the preset opening and the rate of change of the opening is less than the preset rate, it indicates that the vehicle is not in emergency braking. When it is determined that the vehicle is not in emergency braking, the electronic control unit determines the auxiliary braking force and reduces the rate of change of the pitch angle by dynamically adjusting the auxiliary braking force of the front and rear axles, thereby improving the comfort of the driver and passengers. On the contrary, if the vehicle is in emergency braking, the braking system is directly controlled to output the first total braking force to improve the safety of the vehicle.

[0127] Optionally, if the total pedal opening is greater than a preset opening and the opening change rate is less than a preset rate, determining the auxiliary braking force includes:

[0128] If the total pedal opening is greater than a preset opening, and the opening change rate is less than a preset rate, the current steering amplitude and driving speed of the vehicle are determined;

[0129] If the steering amplitude is smaller than the preset amplitude and the driving speed is greater than the preset speed, the auxiliary braking force is determined.

[0130] Among them, the steering amplitude refers to the degree of lateral movement of the vehicle caused by the driver operating the steering wheel during the driving process; the steering amplitude can be characterized by the vehicle's lateral acceleration, steering wheel angle and yaw angular velocity.

[0131] In this embodiment, during the vehicle driving process, after the electronic control unit determines that the total pedal opening is greater than the preset opening and the opening change rate is less than the preset rate, it obtains the current steering amplitude and driving speed of the vehicle through the vehicle bus. The steering amplitude is compared with the preset amplitude, and the driving speed is compared with the preset speed. If the steering amplitude is less than the preset amplitude and the driving speed is greater than the preset speed, the electronic control unit determines the auxiliary braking force.

[0132] For example, the developer can set a preset lateral acceleration, a preset steering wheel angle, a preset yaw rate, and a preset speed for the vehicle. For example, the developer sets a preset lateral acceleration of 2 meters per second (m / s 2 ), the preset steering wheel angle is 50 degrees, the preset yaw rate is 2 radians per second (rad / s), and the preset speed is 60 kilometers per hour (km / h). During vehicle driving, after determining that the total pedal opening is greater than the preset opening and the opening change rate is less than the preset rate, the electronic control unit obtains the vehicle's lateral acceleration of 0.5m / s2, the steering wheel angle is 30 degrees, the yaw rate is 1rad / s, and the speed is 80km / h through the vehicle bus. The electronic control unit determines that the lateral acceleration is less than the preset lateral acceleration, the steering wheel angle is less than the preset steering wheel angle, the yaw rate is less than the preset yaw rate, and the speed is greater than the preset speed. Afterwards, the electronic control unit can determine the auxiliary braking force.

[0133] For another example, during the operation of the vehicle, after determining that the total pedal opening is greater than the preset opening and the opening change rate is less than the preset rate, the electronic control unit obtains the lateral acceleration of the vehicle as 3m / s through the vehicle bus. 2 , the steering wheel angle is 30 degrees, the yaw rate is 1 rad / s, and the speed is 80 km / h. The electronic control unit determines that the steering wheel angle is less than the preset steering wheel angle, the yaw rate is less than the preset yaw rate, the speed is greater than the preset speed, but the lateral acceleration is greater than the preset lateral acceleration. After that, the electronic control unit does not need to determine the auxiliary braking force, and directly controls the braking system to output the first total braking force.

[0134] In an embodiment of the present application, if the total pedal opening is greater than a preset opening, and the rate of change of the opening is less than a preset rate, the electronic control unit can determine the current steering amplitude and the current speed of the vehicle; and determine the auxiliary braking force when the steering amplitude is less than the preset amplitude and the speed is greater than the preset speed. In this embodiment, if the steering amplitude is less than the preset amplitude and the speed is greater than the preset speed, it indicates that the vehicle is braking during high-speed driving in a straight line without emergency braking. If the vehicle brakes during high-speed driving in a straight line, the electronic control unit determines the auxiliary braking force, and reduces the rate of change of the pitch angle by dynamically adjusting the auxiliary braking force of the front and rear axles, thereby further improving the comfort of the driver and passengers. On the contrary, if the vehicle brakes with a large steering amplitude, the electronic control unit directly controls the braking system to output the first total braking force to further improve the safety of the vehicle.

[0135] Optionally, determining the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to the target pitch angle of the vehicle in the current cycle includes:

[0136] The difference between the target pitch angle and the preset pitch angle is determined; when the difference is greater than the preset difference, the allocation ratio is determined.

[0137] In one embodiment, after determining the target pitch angle of the vehicle in the current cycle, the electronic control unit simultaneously obtains a preset pitch angle and calculates the difference between the target pitch angle in the current cycle and the preset pitch angle. If the difference is greater than the preset difference, the electronic control unit can determine the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to the actual difference.

[0138] For example, when the vehicle is driving, the electronic control unit, after determining the target pitch angle of the vehicle in the current cycle, determines whether the difference between the target pitch angle in the current cycle and the preset pitch angle is greater than the preset difference. If the difference is greater than the preset threshold, the difference is input into a pre-designed PID controller to obtain a proportional coefficient output by the PID controller.

[0139] The proportional coefficient output by the PID controller may be a percentage, corresponding to the proportion of the braking force output by the front axle motor or the rear axle motor in the auxiliary braking force. According to the proportional coefficient, the proportion of the front axle motor in the auxiliary braking force and the proportion of the braking force output by the rear axle motor in the auxiliary braking force may be determined. For example, when the proportional coefficient is the proportion of the braking force output by the front axle motor in the auxiliary braking force, if the preset pitch angle is 0 degrees and the preset difference is 3 degrees, the electronic control unit determines that the auxiliary braking force of the vehicle is 60N, and after the target pitch angle in the current cycle is 5 degrees, it can calculate that the difference between the target pitch angle of 5 degrees and the preset pitch angle of 0 degrees is 5 degrees, which is greater than the preset difference of 3 degrees. Afterwards, the electronic control unit can input the difference into the PID controller, and the PID controller outputs the proportional coefficient based on the difference, the proportional coefficient, integral coefficient, differential coefficient, etc. in the PID controller. If the output proportional coefficient is 0.6, it is determined that the proportion of the braking force output by the front axle motor in the auxiliary braking force is 60%, and the proportion of the braking force output by the rear axle motor in the auxiliary braking force can be determined to be 40%. If the auxiliary braking force is 100N, it can be determined that the braking force output by the front axle motor in the next cycle is 60N, and the braking force output by the rear axle motor is 40N.

[0140] On the contrary, during the driving process of the vehicle, after determining the target pitch angle of the vehicle in the current cycle, if the difference between the target pitch angle in the current cycle and the preset pitch angle is not greater than the preset difference, the electronic control unit does not need to determine the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor, and can directly control the braking system to output the first total braking force. For example, if the preset pitch angle is 0 degrees and the preset difference is 3 degrees, the electronic control unit can calculate the difference between the pitch angle and the preset pitch angle as 2 degrees, which is less than the preset difference, after determining that the first total braking force required by the vehicle is 100N and the target pitch angle in the current cycle is 2 degrees. Therefore, the electronic control unit does not need to determine the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor, and can directly control the braking system to output the first total braking force of 100N.

[0141] When the difference is greater than the preset difference, it means that the difference between the preset pitch angle and the target pitch angle in the current cycle is beyond the acceptable range, and the total braking force needs to be adjusted by auxiliary braking force. When the difference is not greater than the preset difference, it means that the difference between the preset pitch angle and the target pitch angle in the current cycle is within the acceptable range, and the total braking force does not need to be adjusted.

[0142] It should be noted that the PID controller can be obtained by researchers and developers adjusting and optimizing various parameters (proportional coefficient, integral coefficient, differential coefficient) in the PID controller based on multiple experiments.

[0143] Optionally, the electronic control unit monitors the vehicle's speed in real time, and when the vehicle's speed is less than a preset speed, the electronic control unit controls the braking system to reduce the corresponding braking force to 0 according to a preset gradient. In this way, the sudden change of the braking force of the braking system when the vehicle is about to stop can be eliminated, thereby reducing the change rate of the pitch angle, and further, it is conducive to maintaining the stability of the vehicle and improving comfort.

[0144] Optionally, the electronic control unit obtains the current speed of the vehicle through the vehicle bus. If the speed is 0, the electronic control unit controls the front axle motor and the rear axle motor not to output braking force. After waiting for a preset time, the electronic control unit can control the braking system to restore the braking force according to a preset gradient. Furthermore, the electronic control unit can control the motor to switch to idle speed control so that it can quickly respond to the driver's acceleration request when necessary.

[0145] In the embodiment of the present application, when the vehicle speed is 0, the electronic control unit can reduce unnecessary energy consumption by controlling the front axle motor and the rear axle motor not to output braking force (i.e., 0 speed control). After waiting for a preset time, the electronic control unit gradually controls the braking system to restore the braking force according to a preset gradient, which can ensure that the vehicle remains stationary, thereby ensuring the safety of the vehicle. The electronic control unit switches the motor to idle control, that is, when the vehicle restarts, it can quickly respond to the driver's acceleration request.

[0146] See also Figure 2 , Figure 2 It is a structural schematic diagram of a vehicle control device provided in an embodiment of the present application. The vehicle control device can be set in an electronic control unit in a vehicle and can include: a first determination module 201, a second determination module 202, a third determination module 203 and a control module 204.

[0147] The first determination module 201 is used to determine the auxiliary braking force when it is detected that the brake pedal of the vehicle is stepped on; wherein the auxiliary braking force is the braking force provided to the vehicle by the front axle motor and the rear axle motor in the vehicle;

[0148] A second determination module 202 is used to determine the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to the target pitch angle of the vehicle in the current cycle;

[0149] The third determination module 203 is used to determine the first braking force provided by the front axle motor to the vehicle in the next adjacent cycle and the second braking force provided by the rear axle motor to the vehicle in the next cycle according to the auxiliary braking force and the distribution ratio;

[0150] The control module 204 is used to control the front axle motor to output a corresponding braking force according to the first braking force, and to control the rear axle motor to output a corresponding braking force according to the second braking force in the next cycle, so as to reduce the pitch angle of the vehicle.

[0151] Optionally, the second determination module 202 is specifically used to determine the predicted pitch angle of the vehicle in the current cycle; when the braking duration is greater than the preset duration, the predicted pitch angle is reduced by a target amplitude according to the braking duration to obtain a target pitch angle; wherein the braking duration is the duration from the moment the brake pedal is pressed to the current moment, and the target amplitude is positively correlated with the braking duration.

[0152] Optionally, the second determination module 202 is specifically used to determine the time difference between the braking duration and the preset duration; determine the target amplitude according to the time difference; wherein the target amplitude is positively correlated with the time difference; and reduce the predicted pitch angle by the target amplitude to obtain the target pitch angle.

[0153] Optionally, the second determination module 202 is specifically configured to obtain a cumulative pitch angle of the vehicle before a current cycle; and determine a predicted pitch angle according to a pitch angle variation and the cumulative pitch angle of the vehicle in the current cycle.

[0154] Optionally, the second determination module 202 is specifically used to obtain dynamic performance parameters of the vehicle and the acceleration of the vehicle in an adjacent previous cycle; wherein the dynamic performance parameters are related to the pitch angle of the vehicle; and determine the pitch angle change according to the dynamic performance parameters, acceleration and cumulative pitch angle.

[0155] Optionally, the first determination module 201 is specifically used to determine the total pedal opening of the brake pedal and the opening change rate when the brake pedal is pressed when it is monitored that the brake pedal is pressed; if the total pedal opening is greater than the preset opening and the opening change rate is less than the preset rate, the auxiliary braking force is determined.

[0156] Optionally, the first determination module 201 is specifically used to determine the current steering amplitude and driving speed of the vehicle if the total pedal opening is greater than a preset opening and the opening change rate is less than a preset rate; if the steering amplitude is less than the preset amplitude and the driving speed is greater than the preset speed, determine the auxiliary braking force.

[0157] The vehicle control device provided in this embodiment can execute the above method embodiment, and its implementation principle and technical effect are similar, which will not be repeated here.

[0158] See also Figure 3 , Figure 3 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

[0159] For example, Figure 3As shown, the vehicle 300 includes: a memory 301 and a processor 302, wherein the memory 301 stores an executable program code 3011, and the processor 302 is used to call and execute the executable program code 3011 to perform a vehicle control method.

[0160] In addition, an embodiment of the present application also protects a vehicle, which may include a memory and a processor, wherein the memory stores an executable program code, and the processor is used to call and execute the executable program code to execute a vehicle control method provided by an embodiment of the present application.

[0161] This embodiment also provides a readable storage medium, in which executable program code is stored. When the executable program code is run on a computer, the computer executes the above-mentioned related method steps to implement a vehicle control method provided by the above-mentioned embodiment.

[0162] This embodiment also provides an executable program code product. When the executable program code product runs on a computer, the computer executes the above-mentioned related steps to implement a vehicle control method provided by the above embodiment.

[0163] Among them, the device, readable storage medium, executable program code product or chip provided in this embodiment are all used to execute the corresponding methods provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0164] 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.

[0165] 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.

[0166] 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 method comprises: When it is detected that the brake pedal of the vehicle is stepped on, an auxiliary braking force is determined; wherein the auxiliary braking force is the braking force provided to the vehicle by the front axle motor and the rear axle motor in the vehicle; determining, according to a target pitch angle of the vehicle in a current cycle, a distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor; Determining, according to the auxiliary braking force and the distribution ratio, a first braking force provided by the front axle motor to the vehicle in a next adjacent cycle, and a second braking force provided by the rear axle motor to the vehicle in the next adjacent cycle; In the next cycle, the front axle motor is controlled to output a corresponding braking force according to the first braking force, and the rear axle motor is controlled to output a corresponding braking force according to the second braking force, so as to reduce the pitch angle of the vehicle.

2. The method according to claim 1, characterized in that Before determining the distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to the target pitch angle of the vehicle in the current cycle, the method further includes: determining a predicted pitch angle of the vehicle during the current cycle; When the braking duration is greater than a preset duration, the predicted pitch angle is reduced by a target amplitude according to the braking duration to obtain the target pitch angle; wherein the braking duration is the duration from the moment the brake pedal is pressed to the current moment, and the target amplitude is positively correlated with the braking duration.

3. The method according to claim 2, characterized in that The step of reducing the predicted pitch angle by a target amplitude according to the braking duration to obtain the target pitch angle includes: Determining a time difference between the braking duration and the preset duration; Determining the target amplitude according to the time difference; wherein the target amplitude is positively correlated with the time difference; The predicted pitch angle is reduced by the target amplitude to obtain the target pitch angle.

4. The method according to claim 2, characterized in that: Determining the predicted pitch angle of the vehicle in the current cycle includes: Obtaining the accumulated pitch angle of the vehicle before the current cycle; The predicted pitch angle is determined according to the pitch angle change amount of the vehicle in the current cycle and the accumulated pitch angle.

5. The method according to claim 4, characterized in that Before determining the predicted pitch angle according to the pitch angle variation of the vehicle in the current cycle and the accumulated pitch angle, the method further includes: Acquire dynamic performance parameters of the vehicle and the acceleration of the vehicle in an adjacent previous cycle; wherein the dynamic performance parameters are related to the pitch angle of the vehicle; The pitch angle variation is determined according to the dynamic performance parameter, the acceleration and the accumulated pitch angle.

6. The method according to claim 1, characterized in that The step of determining the auxiliary braking force when it is detected that the brake pedal of the vehicle is stepped on comprises: When it is detected that the brake pedal is stepped on, determining the total pedal opening of the brake pedal and the rate of change of the opening when the brake pedal is stepped on; If the total pedal opening is greater than a preset opening and the opening change rate is less than a preset rate, the auxiliary braking force is determined.

7. The method according to claim 6, characterized in that If the total pedal opening is greater than a preset opening and the opening change rate is less than a preset rate, determining the auxiliary braking force comprises: If the total pedal opening is greater than a preset opening, and the opening change rate is less than a preset rate, determining the current steering amplitude and driving speed of the vehicle; If the steering amplitude is smaller than a preset amplitude and the driving speed is greater than a preset speed, the auxiliary braking force is determined.

8. A vehicle control device, characterized in that: The device comprises: A first determination module is used to determine the auxiliary braking force when it is detected that the brake pedal of the vehicle is stepped on; wherein the auxiliary braking force is the braking force provided to the vehicle by the front axle motor and the rear axle motor in the vehicle; A second determination module is used to determine a distribution ratio of the auxiliary braking force between the front axle motor and the rear axle motor according to a target pitch angle of the vehicle in a current cycle; a third determining module, configured to determine, according to the auxiliary braking force and the distribution ratio, a first braking force provided by the front axle motor to the vehicle in a next adjacent cycle, and a second braking force provided by the rear axle motor to the vehicle in the next adjacent cycle; A control module is used to control the braking force corresponding to the output of the front axle motor according to the first braking force, and to control the braking force corresponding to the output of the rear axle motor according to the second braking force in the next cycle, so as to reduce the pitch angle of the vehicle.

9. 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 method according to any one of claims 1 to 7.

10. A readable storage medium, characterized in that: The readable storage medium stores executable program codes, and when the executable program codes are executed, the method according to any one of claims 1 to 7 is implemented.

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