An automotive control method and device

Abstract

The present invention provides an automobile control method and device. The method includes: calculating the intended torque of each axle of the whole vehicle by calculating the initial working condition parameters according to a first preset formula; obtaining the first target output torque of the in-wheel motor according to the vehicle fault level of the intended torque of each axle of the whole vehicle; calculating the change amount of the vehicle yaw stability of the in-wheel motor according to the initial working condition parameters, and obtaining the second target output torque of the in-wheel motor according to the change amount and the first target output torque; calculating the third target output torque of the in-wheel motor in the slip state according to the Ackermann steering model; processing the third target output torque according to the current driving mode to obtain the fourth target output torque of the in-wheel motor, and controlling the automobile according to the fourth target output torque. The present invention realizes the treatment of wheel slip and yaw instability of the vehicle under the condition that the maximum power consumption is limited, and reduces the occurrence of safety accidents.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and particularly to an automobile control method and device. Background Art

[0002] Electric vehicles are the future development trend. The configurations of the power systems of electric vehicles include central bridge motors, in-wheel motors, etc. Among them, in-wheel motor vehicles can improve the yaw stability and drive anti-skid performance of vehicles because the torque of each wheel is independently controllable; the use of in-wheel motors has gradually become an important power drive device for electric vehicles.

[0003] In the prior art, the state of in-wheel motor vehicles during operation changes in real time. Generally, algorithms are used to process wheel slip or yaw instability. However, the vehicle may simultaneously experience problems of wheel slip and yaw instability. Moreover, for engineered in-wheel motor vehicles, the torque of the in-wheel motors must be limited in combination with the output capacity of the vehicle's high-voltage system. If the torque of each wheel is not limited, it may lead to faults such as the vehicle losing high voltage and the in-wheel motors losing power, resulting in safety accidents.

[0004] Therefore, there is an urgent need for a control method that can reasonably limit the torque output of each in-wheel motor to ensure that, based on the power output capacity limit of the vehicle's high-voltage system, the control of wheel slip and vehicle lateral instability can be superimposed. Summary of the Invention

[0005] In view of this, it is necessary to provide an automobile control method and device to solve the technical problem in the prior art that it is impossible to control wheel slip and vehicle lateral instability based on the power output capacity limit of the vehicle's high-voltage system.

[0006] On the one hand, the present invention provides an automobile control method, and the method includes:

[0007] Obtain the current driving mode and initial working condition parameters of the vehicle, calculate the intended torque of each axle of the vehicle for the current driving mode according to a first preset formula;

[0008] Obtain the first target output torque of the in-wheel motor according to the vehicle fault level of the intended torque of each axle of the vehicle;

[0009] Calculate the change in the vehicle yaw stability of the in-wheel motor according to the initial working condition parameters, and obtain the second target output torque of the in-wheel motor according to the change and the first target output torque;

[0010] Calculate the third target output torque of the in-wheel motor in the slip state according to the Ackermann steering model for the second target output torque;

[0011] Process the third target output torque according to the current driving mode to obtain the fourth target output torque of the in-wheel motor, and control the vehicle according to the fourth target output torque.

[0012] In some possible implementation manners, the initial operating condition parameters include the actual speed of the in-wheel motor, and the first preset formula includes a centroid speed calculation formula and a centroid rotation speed calculation formula;

[0013] The method for obtaining the current driving mode and initial operating condition parameters of the vehicle, calculating the initial operating condition parameters according to the first preset formula, and obtaining the intended torque of each axis of the whole vehicle in the current driving mode includes:

[0014] Obtain the current driving mode and initial operating condition parameters of the vehicle;

[0015] Determine the formula corresponding to the mode in the centroid speed calculation formula according to the current driving mode;

[0016] Calculate the actual speed of the in-wheel motor according to the formula to obtain the centroid speed;

[0017] Calculate the centroid rotation speed according to the centroid speed and the initial operating condition parameters, and determine the intended torque of each axis of the whole vehicle corresponding to the current driving mode according to the centroid rotation speed.

[0018] In some possible implementation manners, the first target output torque of the in-wheel motor includes the first left target output torque of the left in-wheel motor and the first right target output torque of the right in-wheel motor, the change amount of the in-wheel motor includes the left change amount of the left in-wheel motor and the right change amount of the right in-wheel motor, the second target output torque of the in-wheel motor includes the second left target output torque of the left in-wheel motor and the second right target output torque of the right in-wheel motor, the third target output torque of the in-wheel motor includes the third left target output torque of the left in-wheel motor and the third right target output torque of the right in-wheel motor, and the fourth target output torque of the in-wheel motor includes the fourth left target output torque of the left in-wheel motor and the fourth right target output torque of the right in-wheel motor.

[0019] In some possible implementation manners, the method for obtaining the first target output torque of the in-wheel motor according to the vehicle fault level of the intended torque of each axis of the whole vehicle includes:

[0020] Judge the intended torque of each axis of the whole vehicle according to the vehicle fault level to obtain the first output torque of the in-wheel motor;

[0021] Calculate the maximum output power of the vehicle in the high-voltage system state, and calculate the maximum operating power that evenly distributes the maximum output power to the in-wheel motors according to the maximum output power;

[0022] According to the maximum operating power and the initial operating condition parameters, obtain the maximum torque of the in-wheel motor, and obtain the second output torque of the in-wheel motor according to the maximum torque and the first output torque;

[0023] Calculate the maximum allowable output torque on the left side of the left in-wheel motor and the maximum allowable output torque on the right side of the right in-wheel motor according to the initial operating condition parameters;

[0024] According to the second output torque and the maximum allowable output torque on the left side, obtain the first left target output torque of the left in-wheel motor, and according to the second output torque and the maximum allowable output torque on the right side, obtain the first right target output torque of the right in-wheel motor.

[0025] In some possible implementation manners, the calculating the change amount of the vehicle yaw stability of the in-wheel motor according to the initial operating condition parameters, and obtaining the second target output torque of the in-wheel motor according to the change amount and the first target output torque includes:

[0026] Calculate the additional yaw torque required by the vehicle according to the initial operating condition parameters;

[0027] Allocate the additional yaw torque to the in-wheel motor according to the optimal allocation principle, and determine the left change amount of the vehicle yaw stability of the left in-wheel motor and the right change amount of the vehicle yaw stability of the right in-wheel motor;

[0028] According to the left change amount and the first left target output torque, obtain the second left target output torque of the left in-wheel motor, and according to the right change amount and the first right target output torque, obtain the second right target output torque of the right in-wheel motor.

[0029] In some possible implementation manners, the calculating the third target output torque of the in-wheel motor in the slip state according to the Ackermann steering model for the second target output torque includes:

[0030] Calculate the left slip ratio and left speed difference of the left in-wheel motor, and the right slip ratio and right speed difference of the right in-wheel motor according to the Ackermann steering model;

[0031] Judge whether the left hub motor is in a slipping state according to the left slip ratio and the left rotational speed difference, and judge whether the right hub motor is in a slipping state according to the right slip ratio and the right rotational speed difference;

[0032] When the left hub motor and the right hub motor are in a slipping state, determine the left slip lock-up base torque of the left hub motor and the right slip lock-up base torque of the right hub motor;

[0033] Determine the change amount of the left slip lock-up base torque according to the left slip lock-up base torque, and determine the change amount of the right slip lock-up base torque according to the right slip lock-up base torque. According to the left slip lock-up base torque and the change amount of the left slip lock-up base torque, obtain the third left output torque of the left hub motor, and according to the right slip lock-up base torque and the change amount of the right slip lock-up base torque, obtain the third right output torque of the right hub motor;

[0034] According to the second left target output torque and the third left output torque, obtain the third left target output torque of the left hub motor in a slipping state, and according to the second right target output torque and the third right output torque, obtain the third right target output torque of the right hub motor in a slipping state.

[0035] In some possible implementation manners, the processing the third target output torque according to the current driving mode to obtain the fourth target output torque of the hub motor includes:

[0036] Obtain the fourth left output torque according to the sum or difference of the second left target output torque of the left hub motor and the third left target output torque, and obtain the fourth right output torque according to the sum or difference of the second right target output torque of the right hub motor and the third right target output torque;

[0037] Obtain the fifth left output torque of the left hub motor according to the third left target output torque and the fourth left output torque, and obtain the fifth right output torque of the right hub motor according to the third right target output torque and the fourth right output torque;

[0038] Obtain the fourth left target output torque of the left hub motor according to the fifth left output torque, and obtain the fourth right target output torque of the right hub motor according to the fifth right output torque.

[0039] In some possible implementation manners, obtaining the fourth left target output torque of the left hub motor according to the fifth left output torque, and obtaining the fourth right target output torque of the right hub motor according to the fifth right output torque includes:

[0040] Updating the fifth left output torque and the fifth right output torque to obtain a sixth left output torque and a sixth right output torque that are not negative;

[0041] Processing the sixth left output torque to obtain the fourth left target output torque of the left hub motor, and processing the sixth right output torque to obtain the fourth right target output torque of the right hub motor.

[0042] In some possible implementation manners, after the Ackermann steering model calculates the second target output torque to obtain the third target output torque of the hub motor in the slip state, it further includes:

[0043] Judging whether to perform a minimum operation on the third left target output torque and the third right target output torque according to the current driving mode and the speed at the centroid; the current driving mode includes an off-road mode;

[0044] When the current driving mode is the off-road mode and the speed at the centroid meets the conditions, perform a minimum operation on the third left target output torque and the third right target output torque, and update the third left target output torque and the third right target output torque;

[0045] The processing the sixth left output torque to obtain the fourth left target output torque of the left hub motor, and processing the sixth right output torque to obtain the fourth right target output torque of the right hub motor includes:

[0046] Selecting an output torque according to the current driving mode. When the current driving mode is the off-road mode, determining the updated third left target output torque as the seventh left output torque, and determining the updated third right target output torque as the seventh right output torque; when the current driving mode is not the off-road mode, determining the third left target output torque as the seventh left output torque, and determining the third right target output torque as the seventh right output torque; the current driving mode includes a reverse mode and a regenerative braking mode;

[0047] When the current driving mode is the reverse mode or the braking energy recovery mode, determine the negative of the seventh left output torque as the eighth left output torque, and determine the negative of the seventh right output torque as the eighth right output torque;

[0048] According to the initial operating condition parameters, obtain the torque reduction and torque increment of the slope control duty cycle of the in-wheel motor. Calculate the conditional formula satisfied by the eighth left output torque of the left in-wheel motor according to the torque reduction and the torque increment to obtain the fourth left target output torque of the left in-wheel motor, and calculate the conditional formula satisfied by the eighth right output torque of the right in-wheel motor according to the torque reduction and the torque increment to obtain the fourth right target output torque of the right in-wheel motor.

[0049] On the other hand, the present invention also provides an automotive control device, including:

[0050] The torque calculation module is used to obtain the current driving mode and initial operating condition parameters of the vehicle, and calculate the intended torque of each axle of the whole vehicle in the current driving mode according to a first preset formula;

[0051] The torque limitation module is used to obtain the first target output torque of the in-wheel motor according to the vehicle fault level of the intended torque of each axle of the whole vehicle;

[0052] The yaw stability control is used to calculate the change amount of the vehicle yaw stability of the in-wheel motor according to the initial operating condition parameters, and obtain the second target output torque of the in-wheel motor according to the change amount and the first target output torque;

[0053] The drive anti-skid module is used to calculate the second target output torque according to the Ackermann steering model to obtain the third target output torque of the in-wheel motor in the slip state;

[0054] The torque execution module is used to process the third target output torque according to the current driving mode to obtain the fourth target output torque of the in-wheel motor, and control the vehicle according to the fourth target output torque.

[0055] Correspondingly, an embodiment of the present invention discloses an electronic device, including: a processor, a memory, and a computer program stored on the memory and capable of running on the processor. When the computer program is executed by the processor, it implements each step of the above-mentioned automotive control method embodiment.

[0056] Correspondingly, an embodiment of the present invention discloses a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, each step of the above-mentioned embodiment of the vehicle control method is implemented.

[0057] The beneficial effects of adopting the above embodiment are as follows: The vehicle control method provided by the present invention limits the torque according to the vehicle fault level, which can limit the maximum power of the vehicle, thereby improving the safety of the vehicle. Further, the present invention calculates the change in the vehicle's yaw stability and the third target output torque under the slip state to process the vehicle, so that the vehicle can handle wheel slip and yaw instability when the maximum power is limited, thereby reducing the occurrence of safety accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0059] Figure 1 It is a schematic flowchart of an embodiment of the vehicle control method provided by the present invention;

[0060] Figure 2 It is a schematic structural diagram of an embodiment of the torque calculation module provided by the present invention;

[0061] Figure 3 It is a schematic structural diagram of an embodiment of the vehicle control device provided by the present invention;

[0062] Figure 4 It is a schematic overall structural diagram of an embodiment of the vehicle control device provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0063] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0064] Some of the block diagrams shown in the drawings are functional entities, which do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor systems and / or microcontroller systems.

[0065] As used herein, the mention of "embodiment" means that the specific features, structures, or characteristics described in connection with the embodiment may be included in at least one embodiment of the present invention. The appearance of this phrase at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0066] An embodiment of the present invention provides a vehicle control method and device, which will be described separately below.

[0067] Figure 1 It is a schematic flowchart of an embodiment of the vehicle control method provided by the present invention, as Figure 1 shown, the vehicle control method includes:

[0068] S101. Obtain the current driving mode and initial operating condition parameters of the vehicle, calculate the initial operating condition parameters according to the first preset formula, and obtain the intended torque of each axle of the whole vehicle in the current driving mode;

[0069] S102. Obtain the first target output torque of the in-wheel motor according to the vehicle fault level of the intended torque of each axle of the whole vehicle;

[0070] S103. Calculate the change in the vehicle yaw stability of the in-wheel motor according to the initial operating condition parameters, and obtain the second target output torque of the in-wheel motor according to the change and the first target output torque;

[0071] S104. Calculate the second target output torque according to the Ackermann steering model to obtain the third target output torque of the in-wheel motor in the slip state;

[0072] S105. Process the third target output torque according to the current driving mode to obtain the fourth target output torque of the in-wheel motor, and control the vehicle according to the fourth target output torque.

[0073] It should be noted that the vehicle in the embodiment of the present invention may be an electric vehicle.

[0074] Compared with the prior art, the vehicle control method provided by the present invention limits the torque according to the vehicle fault level, which can limit the maximum power of the electric vehicle, thereby improving the safety of the electric vehicle. Further, the present invention processes the electric vehicle by calculating the change in the vehicle yaw stability and the third target output torque in the slip state, so that the electric vehicle can handle wheel slip and yaw instability under the condition that the maximum power is limited, thereby reducing the occurrence of safety accidents.

[0075] It should be noted that: in order to further obtain the intended torque of each axis of the vehicle for the current driving mode, in step S101, it includes:

[0076] Obtain the current driving mode and initial operating condition parameters of the vehicle;

[0077] Determine the formula corresponding to the mode in the centroid speed calculation formula according to the current driving mode;

[0078] Calculate the actual speed of the in-wheel motor according to the formula to obtain the centroid speed;

[0079] Calculate the centroid speed according to the centroid speed and the initial operating condition parameters, and determine the intended torque of each axis of the vehicle corresponding to the current driving mode according to the centroid speed.

[0080] Among them, the initial operating condition parameters may include the actual speed of the left in-wheel motor, the actual speed of the right in-wheel motor, the wheel radius, the number of axles equipped with in-wheel motors, the steering wheel angle, the wheelbase of the vehicle, the track width, the actual speed of the wheel speed sensor, the throttle opening, and the brake pedal opening, etc.; as Figure 2 shown, the switching of the driving mode and the intended torque can be calculated. The driving mode may include the Stop parking mode, the R gear reverse mode, the N / P gear mode, and the D gear mode; among them, the D gear mode can be divided into: off-road mode, coasting mode, lowest stable speed mode, power mode, economy mode, cruise control mode, adaptive cruise control mode, and regenerative braking mode. The first preset formula may include the centroid speed calculation formula and the centroid speed calculation formula.

[0081] In a specific embodiment of the present invention, the driving mode of the electric vehicle can be switched according to the throttle opening, the brake pedal opening, the N / P gear state, the D gear state, the R gear state, the ignition lock state, the off-road mode switch, the power or economy switch state, and the vehicle centroid speed, and the intended torque T of each axis of the vehicle in each mode is calculated i . The intended torque T of each axis of the vehicle i represents that the left and right in-wheel motors on the i-th axis execute the same driving intention torque. The intended torque T of each axis of the vehicle between different axes i can be the same or different.

[0082] Because the electric vehicle can only be in one of the driving modes at the current state, the centroid speed W of the vehicle can be calculated based on the speeds of all the in-wheel motors of the electric vehicle o, the calculation method is as follows: when the rotational speed in the forward driving state is positive, the speed at the vehicle's center of mass is equal to the minimum value of the speeds calculated to the center of mass according to the Ackermann steering model for each wheel. When the rotational speed in the reverse driving state is negative, the speed at the vehicle's center of mass is equal to the maximum value of the speeds calculated to the center of mass according to the Ackermann steering model for each wheel, obtaining the speed calculation formula at the center of mass. Then, based on the rotational speed calculation formula at the center of mass, the speed and wheel radius at the center of mass are calculated to obtain the rotational speed W at the vehicle's center of mass. o ; among them, the speed calculation formula at the center of mass is shown in formula (1):

[0083]

[0084] In the formula, V o is the speed at the center of mass of the electric vehicle; r is the wheel radius, w il is the actual rotational speed of the left hub motor of the i-th axle, w ir is the actual rotational speed of the right hub motor of the i-th axle, n is the number of axles equipped with hub motors, R il is the Ackermann turning radius of the left hub motor of the i-th axle, R ir is the Ackermann turning radius of the right hub motor of the i-th axle, R0 is the Ackermann turning radius at the vehicle's center of mass, R il 、R ir 、R0 can be obtained by calculating based on the steering wheel angle size, wheelbase, and track width of the vehicle, w il 、w ir can be acquired by collecting with a wheel speed sensor.

[0085] The rotational speed calculation formula at the center of mass is shown in formula (2):

[0086]

[0087] It is also possible to determine the intended torque T of each axle of the whole vehicle corresponding to the current driving mode according to the rotational speed W at the center of mass o , among them, in the N / P mode, parking mode, and coasting mode, T i = 0; in the power mode, the intended torque T of each axle of the whole vehicle at the same throttle opening i is greater than the intended torque T of each axle of the whole vehicle at the same throttle opening in the economy mode i ; in the off-road mode, when the speed at the center of mass of the electric vehicle is less than the set speed V1 (it is recommended to give priority to taking V1 as 10 Km / h), when the brake priority signal is blocked, that is, when the brake pedal and the accelerator pedal are pressed simultaneously, the intended torque T of each axle of the whole vehicle i ; in the off-road mode, when the speed at the center of mass of the electric vehicle is less than the set speed V1 (it is recommended to give priority to taking V1 as 10 Km / h), when the brake priority signal is blocked, that is, when the brake pedal and the accelerator pedal are pressed simultaneously, the intended torque T of each axle of the whole vehicle iThe size is calculated based on the accelerator pedal. However, to avoid the wheels from suddenly slipping forward when the driver steps on both the accelerator pedal and the brake pedal simultaneously and then suddenly releases the brake pedal during a start on a steep slope, causing a safety accident, the intended torque T1 of the first axle of the electric vehicle is limited to be less than T 1max ; In off-road mode, when the speed at the center of mass of the electric vehicle is not less than the set speed V1, to ensure driving safety, the brake priority signal is cancelled, that is, when the brake pedal and the accelerator pedal are stepped on simultaneously, the intended torque T of each axle of the whole vehicle i = 0; At the same time, in off-road mode, the intended torque T of each axle of the whole vehicle with the same throttle opening calculated at the same throttle opening i is greater than the intended torque T of each axle of the whole vehicle with the same throttle opening in the power mode i .

[0088] In some embodiments of the present invention, the first target output torque of the in-wheel motor includes the first left target output torque of the left in-wheel motor and the first right target output torque of the right in-wheel motor. The change amount of the in-wheel motor includes the left change amount of the left in-wheel motor and the right change amount of the right in-wheel motor. The second target output torque of the in-wheel motor includes the second left target output torque of the left in-wheel motor and the second right target output torque of the right in-wheel motor. The third target output torque of the in-wheel motor includes the third left target output torque of the left in-wheel motor and the third right target output torque of the right in-wheel motor. The fourth target output torque of the in-wheel motor includes the fourth left target output torque of the left in-wheel motor and the fourth right target output torque of the right in-wheel motor.

[0089] By calculating the initial working condition parameters of the in-wheel motor in the embodiments of the present invention, the target output torque of the left in-wheel motor and the right in-wheel motor can be obtained, so that the vehicle can operate according to the target output torque.

[0090] In some embodiments of the present invention, in step S102, it includes:

[0091] Judging the intended torque of each axle of the whole vehicle according to the vehicle fault level to obtain the first output torque of the in-wheel motor;

[0092] Calculating the maximum output power of the vehicle in the high-voltage system state, and calculating the maximum available power that evenly distributes the maximum output power to the in-wheel motor according to the maximum output power;

[0093] According to the maximum available power and the initial working condition parameters, obtaining the maximum torque of the in-wheel motor, and obtaining the second output torque of the in-wheel motor according to the maximum torque and the first output torque;

[0094] Calculating the left maximum allowable output torque of the left in-wheel motor and the right maximum allowable output torque of the right in-wheel motor according to the initial working condition parameters

[0095] According to the second output torque and the maximum allowable output torque on the left side, the first left target output torque of the left hub motor is obtained, and according to the second output torque and the maximum allowable output torque on the right side, the first right target output torque of the right hub motor is obtained.

[0096] It should be noted that: since whether the torque of each hub motor can normally respond to the target torque of each wheel has a very important impact on the safety of the hub motor vehicle, if the hub motor wrongly responds to its target torque, it may cause the vehicle to yaw and become unstable, resulting in a vehicle safety accident. Therefore, it is necessary to monitor the torque and monitor the consistency between the actual torque of each hub motor and its target output torque.

[0097] In a specific embodiment of the present invention, the faults occurring in the whole vehicle can be divided into level 0, level 1, level 2, and level 3. Level 0 indicates that there is no fault in the whole vehicle and there is no need to limit the torque. Level 1 indicates a minor fault in the whole vehicle, and there is no need to limit the torque, but an alarm prompt is required. Level 2 indicates a general fault in the whole vehicle, and the target output torque of each axle of the whole vehicle is halved, and an alarm prompt is given. Level 3 indicates a serious fault in the whole vehicle, and the target output torque of each axle of the whole vehicle is set to zero. When it is monitored that the actual torque of each hub motor is consistent with its target output torque, the fault level classification is set to level 0, and if they are inconsistent, the fault level classification is set to level 3. It is also possible to perform a limit processing on the target output torque of each axle of the whole vehicle according to the fault level state of the whole vehicle, and the processing formula is as shown in formula (3):

[0098]

[0099] In the formula, T i1 is the first output torque of the left and right side motors of the i-th axle.

[0100] It is also possible to calculate the maximum output power of the vehicle energy supply system according to the real-time high-voltage system state, and calculate the maximum available power that evenly distributes the maximum output power to all the hub motors on the electric vehicle. The calculation formula is as shown in formula (4):

[0101]

[0102] In the formula, P motormax is the maximum available power allocated to each hub motor based on the vehicle energy supply system, and P max ——The maximum allowable real-time power based on the vehicle energy supply system. In the pure electric mode, it represents the maximum available power of the power battery; in the range extender mode, it represents the maximum available power of the power battery plus the maximum available power of the range extender. γ is a safety factor, and among them, the safety factor γ is preferably taken as 95%.

[0103] First, the maximum torque of the in-wheel motor can be obtained based on the maximum power consumption and the initial operating condition parameters. The calculation formula is as shown in Formula (5):

[0104]

[0105] In the formula, T imax is the maximum torque that the left and right motors on the i-th axis can output based on the vehicle's energy supply system. min(w ir , w il ) is the minimum value of the actual rotational speed w il of the left in-wheel motor and the actual rotational speed w ir of the right in-wheel motor on the i-th axis.

[0106] Next, based on the first output torque T i1 and the maximum torque T imax , calculate the second output torque T i2 of each axis after torque limitation by energy management. The second output torque T i2 should be less than or equal to the maximum torque T imax that the left and right in-wheel motors on the i-th axis can output based on the vehicle's energy supply system. The calculation formula is as shown in Formula (6):

[0107] T i2 = min(T i1 , T imax ) (6)

[0108] Meanwhile, if the actual current of the power battery is still too large and an over-discharge fault occurs, when the actual current I of the power battery is greater than the set value I1, continuously and cumulatively reduce the second output torque T i2 of each axis after torque limitation by energy management until it reaches 0 and then stop reducing. At the same time, when the actual current I of the power battery is less than the set value I2, continuously and cumulatively increase the second output torque T i2 of each axis after torque limitation by energy management, but prevent it from exceeding the maximum value of the cumulative value of the vehicle's intended torque, which is 0, as shown in Formula (7):

[0109] T i2 = max(0, min(T i1 , T imax ) + T) (7)

[0110] In the formula, T is the secondary protection torque of the power battery to prevent over-discharge, T ≤ 0. The calculation formula is as shown in Formula (8):

[0111]

[0112] In the formula, △T is the step change of the power battery to prevent over-discharge, △T > 0.

[0113] The maximum allowable output torque of each in-wheel motor can be calculated according to the external characteristics of the in-wheel motor, and the calculation formula is as shown in formula (9):

[0114]

[0115] In the formula, T f is the peak torque of the in-wheel motor, p f is the peak power of the in-wheel motor, w f is the rotational speed corresponding to the peak power and peak torque of the in-wheel motor, T ilmax is the maximum allowable output torque calculated based on the external characteristics of the in-wheel motor for the left in-wheel motor of the i-th axis, T irmax is the maximum allowable output torque calculated based on the external characteristics of the in-wheel motor for the right in-wheel motor of the i-th axis.

[0116] The first target output torques corresponding to the left and right in-wheel motors can also be calculated based on the maximum allowable output torque, and the calculation formula is as shown in formula (10):

[0117]

[0118] In the formula, T il3 is the first target output torque of the left in-wheel motor of the i-th axis after being limited by the maximum allowable output torque of its in-wheel motor; T ir3 is the first target output torque of the right in-wheel motor of the i-th axis after being limited by the maximum allowable output torque of its in-wheel motor.

[0119] In some embodiments of the present invention, after step S102, it further includes:

[0120] Determine whether the current driving mode performs a minimum operation on the first target output torque; the current driving mode includes an off-road mode;

[0121] When the current driving mode is not the off-road mode, perform a minimum operation on the first target output torque and update the first target output torque.

[0122] In specific embodiments of the present invention, the current driving mode of the electric vehicle can also be determined. When the electric vehicle is in the Stop parking mode, R gear reverse mode, N / P gear mode, in-situ steering mode, coasting mode, lowest stable speed mode, power mode, economy mode, cruise control mode, adaptive cruise control mode, and regenerative braking mode, that is, when the current driving mode is not the off-road mode, a minimum operation can be performed on the first target output torque, and the formula is as shown in formula (11):

[0123]

[0124] When the vehicle is in off-road mode, the minimum selection operation is not performed, that is, as shown in formula (12):

[0125]

[0126] In the formula, T il4 is the first target output torque of the left hub motor of the i-th axle, and T ir4 is the first target output torque of the right hub motor of the i-th axle.

[0127] In some embodiments of the present invention, in step S103, it includes:

[0128] Calculating the additional yaw torque required by the vehicle according to the initial working condition parameters;

[0129] Allocating the additional yaw torque to the hub motor according to the optimal allocation principle, and determining the left change amount of the vehicle yaw stability of the left hub motor and the right change amount of the vehicle yaw stability of the right hub motor;

[0130] Obtaining the second left target output torque of the left hub motor according to the left change amount and the first left target output torque, and obtaining the second right target output torque of the right hub motor according to the right change amount and the first right target output torque.

[0131] In a specific embodiment of the present invention, the additional yaw torque △M required by the electric vehicle can be calculated according to the relative magnitude relationship between the actual yaw center-of-mass angle and the actual yaw angular velocity of the electric vehicle and the ideal yaw center-of-mass angle and the ideal yaw angular velocity, and the maximum value △M max of the additional yaw torque is restricted, that is: △M ≤ △M max , where when the yaw stability control function is turned off, then △M = 0; when the yaw stability control function is turned on and V o ≤ V1 or V o ≥ V2, then △M = 0; when the yaw stability control function is turned on and V1 ≤ V o ≤ V2 and the electric vehicle is in power mode, economy mode, constant speed cruise mode or adaptive cruise mode, calculate △M according to the vehicle stability control requirements; when the yaw stability control function is turned on and V1 ≤ V o ≤ V2 and the vehicle is in Stop parking mode, N / P gear mode, R gear reverse mode, regenerative braking mode, coasting mode, minimum stable speed mode, off-road mode, then △M = 0; when the electric vehicle has a counterclockwise rotation trend, △M is negative, and when the electric vehicle has a clockwise rotation trend, △M is positive. In a specific embodiment, V o is the speed at the center of mass of the electric vehicle, V1 and V2 are set speeds, V2 > V1, V1 = 10 Km / h, and V2 is 15 Km / h.

[0132] The additional yaw torque △M can also be distributed to the in-wheel motors on the left and right sides. The first distribution principle is that the target torque of the in-wheel motor on one side remains unchanged, and the target torque of the in-wheel motor on the other side decreases. The additional yaw torque generated by the decreased torque on the vehicle's center of mass is equal to △M. The first distribution principle is shown in Formulas (13) and (14):

[0133] When △M≥0:

[0134]

[0135] When △M<0:

[0136]

[0137] In the formula, △T il4 is the change amount of the left in-wheel motor of the i-th axle based on the vehicle's yaw stability control, and △T ir4 is the change amount of the right in-wheel motor of the i-th axle based on the vehicle's yaw stability control, and d is the wheelbase.

[0138] The second distribution principle is that the target torque of the in-wheel motor on one side decreases, and the target torque of the in-wheel motor on the other side increases. At the same time, the amount of decrease in the target torque is equal to the amount of increase in the target torque, and the sum of the additional yaw torques generated by the amount of decrease and the amount of increase in the target torque on the vehicle's center of mass is equal to △M. The second distribution principle is shown in Formulas (15) and (16):

[0139] When △M≥0:

[0140]

[0141] When △M<0:

[0142]

[0143] In the embodiment of the present invention, the first distribution principle will cause the target torque of the whole vehicle to become smaller, reducing the power performance of the whole vehicle; the second distribution torque will not change the total sum of the target output torque of the whole vehicle, that is, it will not change the power performance of the whole vehicle. Therefore, the second distribution principle can be preferentially implemented.

[0144] The second target output torque of each in-wheel motor can be calculated based on the change amount of the left in-wheel motor of the i-th axle based on the vehicle's yaw stability control and the change amount of the right in-wheel motor of the i-th axle based on the vehicle's yaw stability control. The calculation formula is shown in Formula (17):

[0145]

[0146] In the formula, T il5is the second target output torque of the left hub motor of the i-th axis after superimposing the change amount of yaw stability control, T ir5 is the second target output torque of the right hub motor of the i-th axis after superimposing the change amount of yaw stability control.

[0147] It should be noted that after obtaining the second target output torque, it is also possible to calculate the target output torque T of the left hub motor of the i-th axis after superimposing the change amount of yaw stability control il5 subtract the difference T of the target output torque of the right hub motor of the i-th axis after superimposing the change amount of yaw stability control ir5 , that is: △T ilr5 = T il5 - T ir5 , where △T ilr5 can represent the increase in the target output torque of the left hub motor of the i-th axis after superimposing the change amount of yaw stability control compared to the target output torque of the right hub motor of the i-th axis after superimposing the change amount of yaw stability control, and also represent the decrease in the target output torque of the right hub motor of the i-th axis after superimposing the change amount of yaw stability control compared to the target output torque of the left hub motor of the i-th axis after superimposing the change amount of yaw stability control.

[0148] In some embodiments of the present invention, in step S104, it includes:

[0149] Calculate the left slip ratio and left speed difference of the left hub motor, and the right slip ratio and right speed difference of the right hub motor according to the Ackermann steering model;

[0150] Judge whether the left hub motor is in a slip state according to the left slip ratio and left speed difference, and judge whether the right hub motor is in a slip state according to the right slip ratio and right speed difference;

[0151] When the left hub motor and the right hub motor are in a slip state, determine the left slip lock-up base torque of the left hub motor and the right slip lock-up base torque of the right hub motor;

[0152] Determine the change amount of the left slip lock-up base torque according to the left slip lock-up base torque, and determine the change amount of the right slip lock-up base torque according to the right slip lock-up base torque. According to the left slip lock-up base torque and the change amount of the left slip lock-up base torque, obtain the third left output torque of the left hub motor, and according to the right slip lock-up base torque and the change amount of the right slip lock-up base torque, obtain the third right output torque of the right hub motor;

[0153] Based on the second left target output torque and the third left output torque, obtain the third left target output torque of the left in-wheel motor in the slip state, and based on the second right target output torque and the third right output torque, obtain the third right target output torque of the right in-wheel motor in the slip state.

[0154] In a specific embodiment of the present invention, the slip ratio and the rotational speed difference of each wheel can be calculated through the Ackermann steering model, and the speed at the vehicle's center of mass can be obtained. When in the forward driving state, the rotational speed is positive, and the speed at the vehicle's center of mass is equal to the minimum value of the speeds of each wheel converted to the center of mass according to the Ackermann steering model; when in the reverse driving state, the rotational speed is negative, and the speed at the vehicle's center of mass is equal to the maximum value of the speeds of each wheel converted to the center of mass according to the Ackermann steering model, as specifically shown in formula (18):

[0155]

[0156] In the formula, w il is the actual rotational speed of the left in-wheel motor of the i-th axle, w ir is the actual rotational speed of the right in-wheel motor of the i-th axle, R il is the Ackermann turning radius of the left in-wheel motor of the i-th axle, R ir is the Ackermann turning radius of the right in-wheel motor of the i-th axle, r is the wheel radius, and R0 is the Ackermann turning radius at the vehicle's center of mass.

[0157] Then, convert the speed at the center of mass of the electric vehicle into the theoretical rotational speeds of each wheel, and the conversion formula is as shown in formula (19):

[0158]

[0159] In the formula, w′ il is the ideal rotational speed of the left in-wheel motor of the i-th axle, w′ ir is the ideal rotational speed of the right in-wheel motor of the i-th axle.

[0160] It is also possible to calculate the slip ratio of each in-wheel motor, and the slip ratio calculation formula is as shown in formula (20):

[0161]

[0162] In the formula, S il is the slip ratio of the left in-wheel motor of the i-th axle, S ir is the slip ratio of the right in-wheel motor of the i-th axle.

[0163] It is also possible to calculate the rotational speed difference of each in-wheel motor, and the rotational speed difference calculation formula is as shown in formula (21):

[0164]

[0165] where, Δw il is the difference between the ideal rotational speed and the actual rotational speed of the left hub motor of the i-th axis, and Δw ir is the difference between the ideal rotational speed and the actual rotational speed of the right hub motor of the i-th axis.

[0166] It is also possible to respectively judge the states of the left and right hub motors. The judgment formula is as shown in formula (22):

[0167]

[0168] where, Sf il is the slip state of the left hub motor of the i-th axis, and Sf ir is the slip state of the right hub motor of the i-th axis, V s1 is the critical vehicle speed 1 for the selection of the slip ratio and rotational speed difference judgment method, and V s2 is the critical vehicle speed 2 for the selection of the slip ratio and rotational speed difference judgment method, that is, V s2 > V s1 . Among them, Sf il = 0 indicates that the left hub motor of the i-th axis is in a normal non-slip state, and Sf il = 1 indicates that the left hub motor of the i-th axis is in a slip state, and Sf ir = 0 indicates that the right hub motor of the i-th axis is in a normal non-slip state, and Sf ir = 1 indicates that the right hub motor of the i-th axis is in a slip state.

[0169] It should be noted that the absolute value of the fourth left target output torque Tout(k - 1) il of the left hub motor of the i-th axis at the previous moment can be obtained, and the absolute value of the execution target torque Tout(k - 1) ir of the right hub motor of the i-th axis at the previous moment can also be obtained, that is, |Tout(k - 1) il | and |Tout(k - 1) ir |.

[0170] The slip lock base torque can be calculated, which represents the base torque that remains unchanged during the process of the wheel being in a slip state, and can enable each wheel to quickly adjust to a stable state. The base torque formula is as shown in formula (23):

[0171]

[0172] where, Ts il is the slip lock base torque of the left hub motor of the i-th axis, and Ts ir is the slip lock base torque of the right hub motor of the i-th axis.

[0173] It is also possible to calculate the change amount △Ts of the in-wheel motor on the left side of the i-th axis with respect to its base torque il and the change amount △Ts of the in-wheel motor on the right side of the i-th axis with respect to its base torque ir . The calculation formula for the change amount is as shown in formula (24):

[0174]

[0175]

[0176] where, if the calculation of △Ts il and △Ts ir is 0 and the wheel is in a slip state, then it is equal to 0; if it is in a slip state, the slip ratio is very large or the rotational speed difference is very large, then △Ts il should be increased, if it is in a slip state, the slip ratio is small or the rotational speed difference is small, then △Ts il should be decreased; at the same time, the range of its change cannot exceed the maximum output torque of its in-wheel motor.

[0177] It is also possible to obtain the corresponding third output torques of the left and right in-wheel motors based on the slip-locked base torque and the change amount of the slip-locked base torque. The calculation formula is as shown in formula (25):

[0178]

[0179] In the formula, Ts1 il is the third left output torque calculated for the in-wheel motor on the left side of the i-th axis, and Ts1 ir is the third right output torque calculated for the in-wheel motor on the right side of the i-th axis.

[0180] It is also possible to judge the state of the wheel. If the wheel is in a non-slip state, then after processing, the second left target output torque T il5 superimposed with the yaw torque and the second right target output torque T il5 are output; if the wheel is in a slip state, then calculate the smaller values corresponding to the second left target output torque T il5 , the second right target output torque T il5 and the third left output torque Ts1 il , the third right output torque Ts1 ir . The calculation formula is as shown in formula (26):

[0181]

[0182] In the formula, T il6 is the third target output torque of the in-wheel motor on the left side of the i-th axis, and T ir6 is the third target output torque of the in-wheel motor on the right side of the i-th axis.

[0183] It should be noted that when the vehicle is in the braking energy recovery mode, Ts il , Ts ir , Ts1 il , Ts1 ir △Ts il , △Ts ir , T il6 , T ir6 The calculated values of are all 0. When the vehicle is in the non-braking energy recovery mode, the calculation is performed according to the calculation process.

[0184] In some embodiments of the present invention, in step S105, it includes:

[0185] Obtain the fourth left output torque based on the sum or difference of the second left target output torques of the left hub motors and the third left target output torque, and obtain the fourth right output torque based on the sum or difference of the second right target output torques of the right hub motors and the third right target output torque;

[0186] Obtain the fifth left output torque of the left hub motor based on the third left target output torque and the fourth left output torque, and obtain the fifth right output torque of the right hub motor based on the third right target output torque and the fourth right output torque;

[0187] Obtain the fourth left target output torque of the left hub motor based on the fifth left output torque, and obtain the fourth right target output torque of the right hub motor based on the fifth right output torque.

[0188] In a specific embodiment of the present invention, in order to ensure that the vehicle stably controls the torque to subtract △T based on T il6 to obtain the fourth right output torque of the right hub motor, as shown in formula (27): ilr5

[0189]

[0189] T ir71 = T il6 -△T ilr5 (27)

[0190] In the formula, T ir71 is the fourth right output torque of the right hub motor of the i-th axis.

[0191] In order to ensure that the torque output by the motor does not exceed the fifth right output torque of the right hub motor of the i-th axis, as shown in formula (28):

[0192] T ir7 = min(T ir71 , T ir6 ) (28)

[0193] In the formula, Tir7 is the fifth right output torque of the right in-wheel motor on the right side of the i-th axis.

[0194] To ensure that the vehicle's stable control torque is based on T ir7 plus △T ilr5 Obtain the fourth left output torque of the left in-wheel motor, as shown in Equation (29):

[0195] T il71 = T ir7 + △T ilr5 (29)

[0196] In the formula, T il71 is the fourth left output torque of the left in-wheel motor on the i-th axis.

[0197] To ensure that the torque output by the motor does not exceed the fifth left output torque of the left in-wheel motor on the i-th axis, as shown in Equation (30):

[0198] T il7 = min(T ir71 , T il6 ) (30)

[0199] In the formula, T il7 is the fifth left output torque of the left in-wheel motor on the i-th axis.

[0200] In some embodiments of the present invention, obtaining the fourth left target output torque of the left in-wheel motor according to the fifth left output torque, and obtaining the fourth right target output torque of the right in-wheel motor according to the fifth right output torque, includes:

[0201] Update the fifth left output torque and the fifth right output torque to obtain a non-negative sixth left output torque and a non-negative sixth right output torque;

[0202] Process the sixth left output torque to obtain the fourth left target output torque of the left in-wheel motor, and process the sixth right output torque to obtain the fourth right target output torque of the right in-wheel motor.

[0203] In a specific embodiment of the present invention, it can be ensured that the left and right in-wheel motors are in a non-negative state, as shown in Equation (31):

[0204]

[0205] In the formula, T il8 is the sixth left output torque of the left in-wheel motor on the i-th axis, and T ir8 is the sixth right output torque of the right in-wheel motor on the i-th axis.

[0206] In some embodiments of the present invention, the Ackermann steering model calculates the second target output torque to obtain the third target output torque of the in-wheel motor in the slip state, further including:

[0207] Determine whether to perform a minimum operation on the third left target output torque and the third right target output torque according to the current driving mode and the speed at the centroid; the current driving mode includes an off-road mode;

[0208] When the current driving mode is the off-road mode and the speed at the centroid meets the conditions, perform a minimum operation on the third left target output torque and the third right target output torque, and update the third left target output torque and the third right target output torque;

[0209] In a specific embodiment of the present invention, it is also possible to judge the current driving mode and the speed at the centroid, and determine whether to perform a minimum operation according to the judgment situation. The judgment formula is shown in Formulas (32)-(33):

[0210] If the vehicle is in the off-road mode and |V o | ≤ V1, no minimum operation is performed:

[0211]

[0212] If the vehicle is in the off-road mode and |V o | ≥ V1, a minimum operation is performed:

[0213] T il9 =T ir9 =min(T il6 ,T ir6 ) (33)

[0214] In the formula, T il9 is the third left target output torque of the left in-wheel motor of the i-th axis, T ir9 is the third right target output torque of the right in-wheel motor of the i-th axis, where V o is the speed at the centroid, and V1 is the set speed, which can be taken as 10 Km / h.

[0215] In some embodiments of the present invention, processing the sixth left output torque to obtain the fourth left target output torque of the left in-wheel motor, and processing the sixth right output torque to obtain the fourth right target output torque of the right in-wheel motor, including:

[0216] Select the output torque according to the current driving mode. When the current driving mode is the off-road mode, determine the updated third left target output torque as the seventh left output torque, and determine the updated third right target output torque as the seventh right output torque; when the current driving mode is not the off-road mode, determine the third left target output torque as the seventh left output torque, and determine the third right target output torque as the seventh right output torque; the current driving mode includes the reverse mode and the braking energy recovery mode;

[0217] When the current driving mode is the reverse mode or the braking energy recovery mode, determine the negative of the seventh left output torque as the eighth left output torque, and determine the negative of the seventh right output torque as the eighth right output torque;

[0218] According to the initial operating condition parameters, obtain the torque reduction and torque increment of the slope control duty cycle of the in-wheel motor. Calculate the condition formula satisfied by the eighth left output torque of the left in-wheel motor according to the torque reduction and torque increment to obtain the fourth left target output torque of the left in-wheel motor, and calculate the condition formula satisfied by the eighth right output torque of the right in-wheel motor according to the torque reduction and torque increment to obtain the fourth right target output torque of the right in-wheel motor.

[0219] In a specific embodiment of the present invention, it is possible to determine whether to select the third target output torque without taking the minimum value or the third target output torque after taking the minimum value.

[0220] In the off-road mode, in order to improve the power output ability of the vehicle, select the third target output torque after taking the minimum value, as shown in formula (34):

[0221]

[0222] In other modes except the off-road mode, in order to improve safety, select the third target output torque without taking the minimum value, as shown in formula (35):

[0223]

[0224] where T il10 is the third left target output torque of the left in-wheel motor of the i-th axis, and T ir10 is the third right target output torque of the right in-wheel motor of the i-th axis.

[0225] In a specific embodiment of the present invention, the positive and negative sign states of each target torque can be determined according to the current driving mode.

[0226] When the vehicle is in the parking mode, N / P mode, off-road mode, coasting mode, minimum steady speed mode, power mode, economy mode, cruise control mode, or adaptive cruise control mode, the torque is positive, as shown in Equation (36):

[0227]

[0228] When the vehicle is in the reverse mode or regenerative braking mode, the torque is negative, as shown in Equation (37):

[0229]

[0230] In the formula, T il11 is the eighth left output torque of the left hub motor of the i-th axle, and T ir11 is the eighth right output torque of the right hub motor of the i-th axle.

[0231] In a specific embodiment of the present invention, the output target torque of each hub motor can be made to slowly change to the eighth left output torque of the left hub motor of the i-th axle and the eighth right output torque of the right hub motor of the i-th axle to meet the vehicle jerk limit requirements. The limiting formulas are shown in Equations (38) and (39):

[0232] When T il11 ≥Tout(k - 1) il :

[0233] Tout(k) il =min(Tout(k - 1) il +ΔTplus i ,T il11 ) (38)

[0234] When T il11 <Tout(k - 1) il :

[0235] Tout(k) il =max(Tout(k - 1) il -ΔTminus i ,T il11 ) (39)

[0236] In the formula, Tout(k) il is the fourth left target output torque of the left hub motor of the i-th axle at the current moment, Tout(k - 1) il is the fourth left target output torque of the left hub motor of the i-th axle at the previous moment, ΔTplus i is the torque increment of the slope control task cycle of the i-th axle hub motor, and ΔTminus iis the torque reduction of the i-th axis hub motor slope control task cycle.

[0237] Where: ΔTplus i and ΔTminus i The value of meets the requirements of the vehicle impact resistance, as shown in formula (40):

[0238]

[0239] In the formula, Δt messageperiod is the period of the message, Δt taskperiod is the execution cycle, j is the limit requirement for the impact strength of the whole vehicle, generally 10, and m is the mass of the unloaded vehicle.

[0240] When T ir11 ≥Tout(k-1) ir When , as shown in formula (41):

[0241] Tout(k) ir =min(Tout(k-1) ir +ΔTplus i ,T ir11 ) (41)

[0242] When T ir11 <Tout(k-1) ir When , as shown in formula (42):

[0243] Tout(k) ir =max(Tout(k-1) ir -ΔTminus i ,T ir11 ) (42)

[0244] Where, Tout(k) ir is the fourth right target output torque of the right wheel hub motor of the i-th axis at the current moment, Tout(k-1) ir It is the fourth right target output torque of the right wheel hub motor of the i-th axis at the previous moment.

[0245] It should be noted that the fourth left target output torque of the left wheel hub motor of the i-th axis at the current moment can be sent to the left wheel absolute value module, and the fourth right target output torque of the right wheel hub motor of the i-th axis at the current moment can be sent to the right wheel absolute value module, so that the left wheel absolute value module and the right wheel absolute value module can process the fourth target output torque.

[0246] After obtaining the fourth left target output torque of the left hub motor of the i-th axis and the fourth right target output torque of the right hub motor of the i-th axis at the current moment, the electric vehicle can be driven according to the fourth target output torque, so as to ensure that on the basis of the power output capacity limit of the vehicle's high-voltage system, the situations of wheel slip and vehicle lateral instability can be handled, and the safety of the electric vehicle can be improved.

[0247] To better implement the vehicle control method in the embodiments of the present invention, correspondingly, the embodiments of the present invention further provide a vehicle control device, as Figure 3 shown, the device includes;

[0248] A torque calculation module 201, configured to obtain the current driving mode and initial condition parameters of the vehicle, calculate the initial condition parameters according to a first preset formula, and obtain the intended torque of each axis of the vehicle in the current driving mode;

[0249] A torque limitation module 202, configured to obtain the first target output torque of the hub motor according to the vehicle fault level of the intended torque of each axis of the vehicle;

[0250] A yaw stability control 203, configured to calculate the change amount of the vehicle yaw stability of the hub motor according to the initial condition parameters, and obtain the second target output torque of the hub motor according to the change amount and the first target output torque;

[0251] A drive anti-skid module 204, configured to calculate the second target output torque according to the Ackerman steering model, and obtain the third target output torque of the hub motor in the slip state;

[0252] A torque execution module 205, configured to process the third target output torque according to the current driving mode, obtain the fourth target output torque of the hub motor, and control the vehicle according to the fourth target output torque.

[0253] In a specific embodiment of the present invention, as Figure 4 shown, Figure 4 is a schematic structural diagram of an embodiment of the vehicle control method provided by the present invention. The current driving mode and initial parameters of the electric vehicle can be obtained through the driving mode switching and intended torque calculation module, and the intended torque T of each axis of the vehicle corresponding to the current driving mode can be calculated through formulas (1) and (2) i , the consistency between the actual torque of each hub motor and its target output torque can be monitored through the torque monitoring module, and a fault level classification module is also set to classify the faults occurring in the vehicle into level 0, level 1, level 2, and level 3. However, when the torque fault limitation module receives T i , it can judge T through formula (3) ito obtain the first output torque T at a certain level i1 Furthermore, the maximum torque T can be calculated through formulas (4) and (5) of the energy management power distribution module imax For the energy management torque limit, T can be calculated according to formulas (6), (7), and (8) i1 and T imax to obtain the second output torque T i2 For the motor output ability calculation module, the left maximum allowable output torque T of each in-wheel motor can be calculated through formula (9) ilmax and the right maximum allowable output torque T irmax For the motor ability limit module, T can be calculated through formula (10) ilmax 、T irmax and T i2 to obtain the first left target output torque T il3 and the first right target output torque T ir3 .

[0254] It is also possible to set a module for taking the smaller value for coaxial shafts. Through formulas (11) and (12), T il3 and T ir3 are updated to obtain the updated T il4 and T ir4 .

[0255] The additional yaw torque △M required for the electric vehicle can also be calculated by the yaw torque calculation module. The yaw torque distribution module calculates the change △T of the left in-wheel motor through formulas (13), (14), (15), and (16) il4 and the change △T of the right in-wheel motor ir4 . The superimposed yaw torque module calculates the change △T il4 , the change △T ir4 , T il3 and T ir3 through formula (17) to obtain the second left target output torque of the left in-wheel motor and the second right target output torque of the right in-wheel motor. A difference calculation module can also be set. After obtaining the second target output torque, the difference T between the target output torque T il5 of the left in-wheel motor on the i-th axis after the change amount of the superimposed yaw stability control and the target output torque of the right in-wheel motor on the i-th axis after the change amount of the superimposed yaw stability control can also be calculated by the difference calculation module ir5 , that is: △T ilr5 =T il5 -T ir5 , △T ilr5It can be expressed as the increase in the target output torque of the right hub motor or as the decrease in the target output torque of the left hub motor.

[0256] The slip ratio calculation module can calculate the slip ratio and rotational speed difference of each wheel through equations (18), (19), (20), and (21) in the Ackermann steering model. It can also judge equation (22) based on the states of the left and right hub motors through the left wheel slip state recognition module and the right wheel slip state recognition module to obtain the slip state Sf of the left hub motor il and the slip state Sf of the right hub motor ir , and through the left wheel absolute value module, the absolute value of the fourth target output torque Tout(k - 1) of the left hub motor on the i - th axis at the previous moment can be obtained il , and through the right absolute value module, the absolute value of the execution target torque Tout(k - 1) of the right hub motor on the i - th axis at the previous moment can be obtained ir , that is, |Tout(k - 1) il | and |Tout(k - 1) ir |. Through the left wheel drive anti - slip basic torque lock - up module and the right wheel drive anti - slip basic torque lock - up module, the basic torque that remains locked and unchanged during the process of the wheel being in the slip state can be characterized, enabling each wheel to quickly adjust to a stable state. Through equation (23), the left - hand slip lock - up basic torque Ts of the left hub motor can be obtained il and the right - hand slip lock - up basic torque Ts of the right hub motor ir , and the left wheel drive anti - slip control calculation torque module and the right wheel drive anti - slip control calculation torque module can obtain the third left - hand output torque Ts1 calculated by the left hub motor il and the third right - hand output torque Ts1 calculated by the right hub motor ir , and the left wheel torque path switching module and the right wheel torque path switching module can calculate T il5 , T ir5 , Ts1 il and Ts1 ir through equations (26) to obtain the third left - hand target output torque T il6 of the left hub motor and the third right - hand target output torque T ir6 of the right hub motor.

[0257] The right difference interlock module subtracts △T il6 from T ilr5 as the basis to ensure stable vehicle control torque to obtain the fourth right - hand output torque T ir71, as shown in formula (27), the right-wheel Min module ensures that the torque output by the motor does not exceed the fifth right-side output torque T of the right-side hub motor of the i-th axis after passing through the torque path switching module ir7 , as shown in formula (28), the left differential interlock module ensures that the vehicle stability control torque is based on T ir7 plus △T ilr5 to obtain the fourth left-side output torque T of the left-side hub motor il71 , as shown in formula (29), the left-wheel Min ensures that the torque output by the motor does not exceed the fifth left-side output torque T of the left-side hub motor of the i-th axis after passing through the torque path switching module il7 , as shown in formula (30).

[0258] The left-wheel torque overrun verification module and the right-wheel torque overrun verification module can ensure that the left and right side hub motors are not in a negative state through formula (31), and obtain the sixth left-side output torque T of the left-side hub motor of the i-th axis after passing through the torque range verification module il8 and the sixth right-side output torque T of the right-side hub motor of the i-th axis after passing through the torque range verification module ir8 .

[0259] It is also possible to judge the current driving mode and the speed at the center of mass through the coaxial minimum selection module, and determine whether to perform the minimum selection operation according to the judgment situation. The judgment formulas are as shown in formulas (32)-(33), and obtain the third left-side target output torque T of the left-side hub motor of the i-th axis after passing through the coaxial minimum selection module 2 il9 and the third right-side target output torque T of the right-side hub motor of the i-th axis after passing through the coaxial minimum selection module 2 ir9 .

[0260] It is possible to judge through the torque selection module whether to select the third target output torque of the torque range verification module or the third target output torque after passing through the coaxial minimum selection module 2, and calculate through the formulas corresponding to different modes, such as formulas (34) and (35), to obtain the third left-side target output torque T of the left-side hub motor of the i-th axis after passing through the torque selection module il10 and the third right-side target output torque T of the right-side hub motor of the i-th axis after passing through the torque selection module ir10 .

[0261] It is possible to determine the positive and negative sign states of each target torque through the torque sign switching module according to the current driving mode, and calculate through the formulas corresponding to different modes, such as formulas (36) and (37), to obtain the eighth left-side output torque T of the left-side hub motor of the i-th axis after passing through the torque sign switching module il11 and the eighth right-side output torque T of the right-side hub motor of the i-th axis after passing through the torque sign switching module ir11 .

[0262] The output target torque of each in-wheel motor can be made to slowly change to satisfy the vehicle impact limit requirement through the torque slope control module to the eighth output torque of the left in-wheel motor of the i-th axis after passing through the torque sign switching module and the eighth output torque of the right in-wheel motor of the i-th axis after passing through the torque sign switching module. The limiting formulas are as shown in Formula (38) and Formula (39), and the fourth left target output torque Tout(k) of the left in-wheel motor of the i-th axis at the current moment after passing through the torque slope control module is obtained. il , and through Formula (40), Formula (41) and Formula (42), the fourth right target output torque Tout(k) of the right in-wheel motor of the i-th axis at the current moment after passing through the torque slope control module is obtained. ir .

[0263] An embodiment of the present invention further provides an electronic device, including:

[0264] It includes a processor, a memory, and a computer program stored on the memory and capable of running on the processor. When the computer program is executed by the processor, it realizes each process of the above-mentioned embodiment of the vehicle control method and can achieve the same technical effect. To avoid repetition, it will not be elaborated here.

[0265] An embodiment of the present invention further provides a computer-readable storage medium. A computer program is stored on the computer-readable storage medium. When the computer program is executed by the processor, it realizes each process of the above-mentioned embodiment of the vehicle control method and can achieve the same technical effect. To avoid repetition, it will not be elaborated here.

[0266] Each embodiment in this specification is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0267] Those skilled in the art can understand that all or part of the processes of implementing the above-mentioned embodiment methods can be completed by instructing relevant hardware (such as a processor, a controller, etc.) through a computer program. The computer program can be stored in a computer-readable storage medium. Among them, the computer-readable storage medium is a disk, an optical disc, a read-only memory, or a random access memory, etc.

[0268] The above has introduced in detail the vehicle control method and device provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A vehicle control method, characterized in that, Including: Obtain the current driving mode and initial operating condition parameters of the vehicle, calculate the initial operating condition parameters according to a first preset formula, and obtain the intended torque of each axle of the vehicle for the current driving mode; Obtain the first target output torque of the in-wheel motor according to the vehicle fault level of the intended torque of each axle of the vehicle; Calculate the change in vehicle yaw stability of the in-wheel motor according to the initial operating condition parameters, and obtain the second target output torque of the in-wheel motor according to the change and the first target output torque; Calculate the third target output torque of the in-wheel motor in the slip state according to the Ackermann steering model; Process the third target output torque according to the current driving mode to obtain the fourth target output torque of the in-wheel motor, and control the vehicle according to the fourth target output torque; The initial operating condition parameters include the actual speed of the in-wheel motor, and the first preset formula includes a center-of-mass speed calculation formula and a center-of-mass speed calculation formula; The obtaining the current driving mode and initial operating condition parameters of the vehicle, calculating the initial operating condition parameters according to a first preset formula, and obtaining the intended torque of each axle of the vehicle for the current driving mode includes: Obtain the current driving mode and initial operating condition parameters of the vehicle; Determine the formula corresponding to the mode in the center-of-mass speed calculation formula according to the current driving mode; Calculate the center-of-mass speed according to the formula for the actual speed of the in-wheel motor; Calculate the center-of-mass speed according to the center-of-mass speed and the initial operating condition parameters, and determine the intended torque of each axle of the vehicle corresponding to the current driving mode according to the center-of-mass speed; The first target output torque of the in-wheel motor includes the first left target output torque of the left in-wheel motor and the first right target output torque of the right in-wheel motor, the change of the in-wheel motor includes the left change of the left in-wheel motor and the right change of the right in-wheel motor, the second target output torque of the in-wheel motor includes the second left target output torque of the left in-wheel motor and the second right target output torque of the right in-wheel motor, the third target output torque of the in-wheel motor includes the third left target output torque of the left in-wheel motor and the third right target output torque of the right in-wheel motor, and the fourth target output torque of the in-wheel motor includes the fourth left target output torque of the left in-wheel motor and the fourth right target output torque of the right in-wheel motor; The calculating the change in vehicle yaw stability of the in-wheel motor according to the initial operating condition parameters, and obtaining the second target output torque of the in-wheel motor according to the change and the first target output torque includes: Calculate the additional yaw torque required by the vehicle according to the initial operating condition parameters; Allocate the additional yaw torque to the in-wheel motor according to the optimal allocation principle, and determine the left change in vehicle yaw stability of the left in-wheel motor and the right change in vehicle yaw stability of the right in-wheel motor; Obtain the second left target output torque of the left hub motor based on the left change amount and the first left target output torque, and obtain the second right target output torque of the right hub motor based on the right change amount and the first right target output torque; The calculation of the third target output torque of the hub motor in the slip state according to the Ackermann steering model includes: Calculate the left slip ratio and left speed difference of the left hub motor, and the right slip ratio and right speed difference of the right hub motor according to the Ackermann steering model; Judge whether the left hub motor is in the slip state according to the left slip ratio and the left speed difference, and judge whether the right hub motor is in the slip state according to the right slip ratio and the right speed difference; When the left hub motor and the right hub motor are in the slip state, determine the left slip lock base torque of the left hub motor and the right slip lock base torque of the right hub motor; Determine the left slip lock base torque change amount according to the left slip lock base torque, and determine the right slip lock base torque change amount according to the right slip lock base torque. Obtain the third left output torque of the left hub motor according to the left slip lock base torque and the left slip lock base torque change amount, and obtain the third right output torque of the right hub motor according to the right slip lock base torque and the right slip lock base torque change amount; Obtain the third left target output torque of the left hub motor in the slip state according to the second left target output torque and the third left output torque, and obtain the third right target output torque of the right hub motor in the slip state according to the second right target output torque and the third right output torque; The calculation formula for the speed at the center of mass is as follows: Wherein, is the speed at the center of mass of the electric vehicle; is the wheel radius, is the actual rotational speed of the in-wheel motor on the left side of the th axle, is the actual rotational speed of the in-wheel motor on the right side of the th axle, is the Ackermann turning radius of the in-wheel motor on the left side of the th axle, is the Ackermann turning radius of the in-wheel motor on the right side of the th axle, is the Ackermann turning radius at the center of mass of the vehicle, , , are calculated based on the steering wheel angle, wheelbase, and track width of the vehicle, , are acquired by the wheel speed sensors; The calculation formula for the rotational speed at the center of mass is as follows: In the formula, is the rotational speed at the centroid.

2. The vehicle control method according to claim 1, wherein The obtaining of the first target output torque of the hub motor according to the vehicle fault level of the intended torque of each axle of the whole vehicle includes: Judge the intended torque of each axle of the whole vehicle according to the vehicle fault level to obtain the first output torque of the hub motor; Calculate the maximum output power of the vehicle in the high-voltage system state, and calculate the maximum available power that evenly distributes the maximum output power to the hub motor according to the maximum output power; Obtain the maximum torque of the hub motor according to the maximum available power and the initial operating condition parameters, and obtain the second output torque of the hub motor according to the maximum torque and the first output torque; Calculate the left maximum allowable output torque of the left hub motor and the right maximum allowable output torque of the right hub motor according to the initial operating condition parameters; Based on the second output torque and the maximum allowable left-side output torque, a first left-side target output torque of the left-side in-wheel motor is obtained, and based on the second output torque and the maximum allowable right-side output torque, a first right-side target output torque of the right-side in-wheel motor is obtained.

3. The vehicle control method according to claim 2, characterized in that, The processing of the third target output torque according to the current driving mode to obtain the fourth target output torque of the in-wheel motor includes: Based on the sum or difference of the second left-side target output torque of the left-side in-wheel motor and the third left-side target output torque, a fourth left-side output torque is obtained, and based on the sum or difference of the second right-side target output torque of the right-side in-wheel motor and the third right-side target output torque, a fourth right-side output torque is obtained; Based on the third left-side target output torque and the fourth left-side output torque, a fifth left-side output torque of the left-side in-wheel motor is obtained, and based on the third right-side target output torque and the fourth right-side output torque, a fifth right-side output torque of the right-side in-wheel motor is obtained; Based on the fifth left-side output torque, a fourth left-side target output torque of the left-side in-wheel motor is obtained, and based on the fifth right-side output torque, a fourth right-side target output torque of the right-side in-wheel motor is obtained.

4. The vehicle control method according to claim 3, wherein, The obtaining of the fourth left-side target output torque of the left-side in-wheel motor based on the fifth left-side output torque and the obtaining of the fourth right-side target output torque of the right-side in-wheel motor based on the fifth right-side output torque include: Updating the fifth left-side output torque and the fifth right-side output torque to obtain a non-negative sixth left-side output torque and a sixth right-side output torque; Processing the sixth left-side output torque to obtain a fourth left-side target output torque of the left-side in-wheel motor, and processing the sixth right-side output torque to obtain a fourth right-side target output torque of the right-side in-wheel motor.

5. The vehicle control method according to claim 4, wherein, After the Ackermann steering model calculates the second target output torque to obtain the third target output torque of the in-wheel motor in the slip state, it further includes: Judging whether to perform a minimum operation on the third left-side target output torque and the third right-side target output torque according to the current driving mode and the speed at the centroid; the current driving mode includes an off-road mode; When the current driving mode is the off-road mode and the speed at the centroid meets the conditions, perform a minimum operation on the third left-side target output torque and the third right-side target output torque, and update the third left-side target output torque and the third right-side target output torque; The processing of the sixth left-side output torque to obtain a fourth left-side target output torque of the left-side in-wheel motor and the processing of the sixth right-side output torque to obtain a fourth right-side target output torque of the right-side in-wheel motor include: Select the output torque according to the current driving mode. When the current driving mode is the off-road mode, determine the updated third left target output torque as the seventh left output torque, and determine the updated third right target output torque as the seventh right output torque; when the current driving mode is not the off-road mode, determine the third left target output torque as the seventh left output torque, and determine the third right target output torque as the seventh right output torque; the current driving mode includes the reverse mode and the regenerative braking mode; When the current driving mode is the reverse mode or the regenerative braking mode, determine the negative value of the seventh left output torque as the eighth left output torque, and determine the negative value of the seventh right output torque as the eighth right output torque; According to the initial working condition parameters, obtain the torque reduction and torque increment of the slope control task cycle of the in-wheel motor. Calculate the conditional formula satisfied by the eighth left output torque of the left in-wheel motor according to the torque reduction and the torque increment, to obtain the fourth left target output torque of the left in-wheel motor, and calculate the conditional formula satisfied by the eighth right output torque of the right in-wheel motor according to the torque reduction and the torque increment, to obtain the fourth right target output torque of the right in-wheel motor.

6. An automobile control device, characterized in that, Including: A torque calculation module, configured to obtain the current driving mode and initial working condition parameters of the vehicle, and calculate the intended torque of each axle of the vehicle in the current driving mode according to a first preset formula; A torque limit module, configured to obtain the first target output torque of the in-wheel motor according to the vehicle fault level of the intended torque of each axle of the vehicle; A yaw stability control module, configured to calculate the change amount of the vehicle yaw stability of the in-wheel motor according to the initial working condition parameters, and obtain the second target output torque of the in-wheel motor according to the change amount and the first target output torque; A drive anti-skid module, configured to calculate the second target output torque according to the Ackermann steering model, to obtain the third target output torque of the in-wheel motor in the slip state; A torque execution module, configured to process the third target output torque according to the current driving mode, to obtain the fourth target output torque of the in-wheel motor, and control the vehicle according to the fourth target output torque; The initial working condition parameters include the actual speed of the in-wheel motor, and the first preset formula includes a centroid speed calculation formula and a centroid rotation speed calculation formula; The torque calculation module is further configured to obtain the current driving mode and initial working condition parameters of the vehicle; Determine the formula corresponding to the mode in the centroid speed calculation formula according to the current driving mode; Calculate the centroid speed according to the formula and the actual speed of the in-wheel motor; Calculate the centroid rotation speed according to the centroid speed and the initial working condition parameters, and determine the intended torque of each axle of the vehicle corresponding to the current driving mode according to the centroid rotation speed; The first target output torque of the in-wheel motor includes the first left target output torque of the left in-wheel motor and the first right target output torque of the right in-wheel motor. The change amount of the in-wheel motor includes the left change amount of the left in-wheel motor and the right change amount of the right in-wheel motor. The second target output torque of the in-wheel motor includes the second left target output torque of the left in-wheel motor and the second right target output torque of the right in-wheel motor. The third target output torque of the in-wheel motor includes the third left target output torque of the left in-wheel motor and the third right target output torque of the right in-wheel motor. The fourth target output torque of the in-wheel motor includes the fourth left target output torque of the left in-wheel motor and the fourth right target output torque of the right in-wheel motor; The yaw stability control module is further configured to calculate the additional yaw torque required by the vehicle according to the initial working condition parameters; distribute the additional yaw torque to the in-wheel motor according to the optimal distribution principle, and determine the left change amount of the vehicle yaw stability of the left in-wheel motor and the right change amount of the vehicle yaw stability of the right in-wheel motor; obtain the second left target output torque of the left in-wheel motor according to the left change amount and the first left target output torque, and obtain the second right target output torque of the right in-wheel motor according to the right change amount and the first right target output torque; The drive anti-skid module is further configured to calculate the left slip ratio and the left speed difference of the left in-wheel motor, and the right slip ratio and the right speed difference of the right in-wheel motor according to the Ackermann steering model; determine whether the left in-wheel motor is in a slip state according to the left slip ratio and the left speed difference, and determine whether the right in-wheel motor is in a slip state according to the right slip ratio and the right speed difference; In the case where the left in-wheel motor and the right in-wheel motor are in a slip state, determine the left slip lock base torque of the left in-wheel motor and the right slip lock base torque of the right in-wheel motor; determine the left slip lock base torque change amount according to the left slip lock base torque, and determine the right slip lock base torque change amount according to the right slip lock base torque. Obtain the third left output torque of the left in-wheel motor according to the left slip lock base torque and the left slip lock base torque change amount, and obtain the third right output torque of the right in-wheel motor according to the right slip lock base torque and the right slip lock base torque change amount; obtain the third left target output torque of the left in-wheel motor in the slip state according to the second left target output torque and the third left output torque, and obtain the third right target output torque of the right in-wheel motor in the slip state according to the second right target output torque and the third right output torque; The calculation formula for the speed at the center of mass is as follows: Wherein, is the speed at the center of mass of the electric vehicle; is the wheel radius, is the actual rotational speed of the left hub motor of the th axle, is the actual rotational speed of the right hub motor of the th axle, is the number of axles equipped with hub motors, is the Ackermann turning radius of the left hub motor of the th axle, is the Ackermann turning radius of the right hub motor of the th axle, is the Ackermann turning radius at the center of mass of the vehicle, , , are calculated based on the steering wheel angle, wheelbase, and track width of the vehicle, , are acquired by wheel speed sensors; The calculation formula for the rotational speed at the center of mass is as follows: In the formula, is the rotational speed at the centroid.

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