WO2021147943A1

WO2021147943A1 - Vehicle, and method and system for controlling same

Info

Publication number: WO2021147943A1
Application number: PCT/CN2021/073028
Authority: WO
Inventors: 何湘雨; 邓乐; 蔡年春; 张忠政
Original assignee: 长沙智能驾驶研究院有限公司
Priority date: 2020-01-21
Filing date: 2021-01-21
Publication date: 2021-07-29
Also published as: CN113212181A; CN113212181B

Abstract

A method and system for controlling a vehicle. A vehicle comprises multiple electric drive axles, and a group of wheels, a corresponding motor, and a motor controller are provided at both sides of each electric drive axle. The method comprises: obtaining a total request torque at least according to a state signal of the vehicle; determining the number of workable electric drive axles in the electric drive axles; determining the priorities of the workable electric drive axles at least according to a mileage traveled by the vehicle; and determining, at least according to the priorities of the workable electric drive axles and the total request torque, torques to be distributed corresponding to the workable electric drive axles. By means of the method for controlling a vehicle, a torque can be distributed to each electric drive axle depending on efficiency, and the priority of each electric drive axle can be rotated according to the traveling mileage, so that the wear of a vehicle transmission system can be balanced.

Description

Vehicle and its control method and control system

Technical field

The invention relates to the field of intelligent control, in particular to a vehicle and its control method and control system.

Background technique

With the development of the economic level, more and more vehicles are being put into actual production and life applications, which brings great convenience to people. Towing trailers are the main means of transportation in my country. With the growth of my country's logistics and freight demand, more and more trucks with trailers running on expressways have brought tremendous pressure to environmental protection and also brought energy-saving reductions. Platoon demand. Therefore, new energy trailers with hybrid power are the direction of various manufacturers' active research and development. At present, hybrid vehicles with new energy trailers mainly add drive motors to the trailers to form an electric drive axle to provide auxiliary driving force when the vehicle is driving, and to recover energy during deceleration to achieve energy-saving effects. The modification schemes for trailers mainly include centralized electric drive axle and multi-axis distributed electric drive axle. Compared with centralized electric drive axle, the system of multi-axis distributed electric drive axle is more flexible but relatively complicated. Characteristics, it is necessary to consider the management and control of the torque output by the motors of each electric drive axle when driving at high speeds or special roads for a long time to deal with the driving conditions of the vehicle and the special circumstances that may occur during driving.

The current multi-axis distributed electric drive axle control mostly relies on historical experience, setting some parameters for specific control, and in actual applications, the road conditions are complex and changeable, and vehicles under different conditions will also be different. If the presets are used uniformly It is obviously impossible to realize the reasonable and effective management of the multi-axis distributed electric drive axle in the vehicle.

Summary of the invention

In view of the technical problems in the prior art, the present invention proposes a vehicle control method, wherein the vehicle includes a plurality of electric drive axles, and each electric drive axle is provided with a set of wheels and corresponding motors on both sides And a motor controller, wherein the method includes: obtaining a total requested torque at least according to the state signal of the vehicle; determining the number of workable electric drive axles in the electric drive axle; and determining the number of electric drive axles at least according to the mileage that the vehicle has traveled. The priority of the workable electric drive axle; and the assigned torque corresponding to the workable electric drive axle is determined at least according to the priority of the workable electric drive axle and the total requested torque.

The control method as described above further includes determining whether the distributed torque needs to be limited during output at least according to the slip rate of the vehicle wheel or the temperature of the motor/motor controller.

The control method as described above, wherein, determining the priority of the workable electric drive axle at least according to the mileage that the vehicle has traveled includes: according to the accumulated mileage of the vehicle and a preset priority adjustment rule, when the preset priority is reached When the mileage threshold is used, the priority order of the workable electric drive axle is adjusted.

The above-mentioned control method further includes: obtaining the motor speed of the workable electric drive axle; and under the premise of maximizing the total efficiency of the vehicle system, at least according to the total requested torque and the workable electric drive axle The rotation speed of the motor and the priority of the workable electric drive axle obtain the assigned torque corresponding to the workable electric drive axle.

The control method as described above, wherein determining whether it is necessary to limit the distributed torque according to at least the slip rate of the vehicle includes: obtaining the operating speed of the vehicle and the rotation speed of each group of wheels; and at least according to the operation Speed and the wheel rotation speed, determine the slip rate of each group of wheels; compare the wheel slip rate with a preset slip rate threshold range; when the wheel slip rate is less than the preset slip rate threshold range When the limit value is set, there is no need to limit the distributed torque of the corresponding workable electric drive axle when output; when the wheel slip rate is greater than the upper limit of the preset slip rate threshold range, the corresponding output needs to be adjusted The distributed torque of the workable electric drive axle is limited.

The control method as described above, wherein when the wheel slip rate falls within the preset slip rate threshold range, the assigned torque of the corresponding workable electric drive axle and the absolute value of its current torque are smaller by one者 as output.

The control method as described above, wherein when the wheel slip rate is greater than the upper limit of the preset slip rate threshold range, the amplitude of the distribution torque of the corresponding workable electric drive axle needs to be limited when outputting It needs to be satisfied that the wheel slip rate is not greater than the upper limit of the preset slip rate threshold range.

The control method as described above, wherein when the wheel slip rate is greater than the upper limit of the preset slip rate threshold range, it is necessary to limit the distributed torque of the corresponding workable electric drive axle when outputting, including : For the first-priority workable electric drive axle, when its corresponding wheel slip rate is greater than the upper limit value, reduce its assigned torque; and reduce the assigned torque of the first-priority workable electric drive axle Workable electric drive axles that are allocated to other priority levels.

The control method as described above, wherein when the wheel slip rate corresponding to one or more other workable electric drive axles is also greater than the upper limit of the preset slip rate threshold range, the first priority can be The reduced distribution torque of the working electric drive axle is no longer apportioned; and the distribution torque of the other working electric drive axles is limited to satisfy that the corresponding wheel slip rate is not greater than the preset slip rate threshold range Limit.

The control method as described above, wherein determining whether it is necessary to limit the distributed torque according to at least the temperature of the vehicle includes: obtaining the temperature of the motor and/or the motor controller corresponding to the workable electric drive axle; and According to the degree to which the temperature exceeds the preset temperature threshold, the distributed torque of the corresponding workable electric drive axle is correspondingly limited.

According to another aspect of the present application, a vehicle control system is proposed, wherein the vehicle includes a plurality of electric drive axles, and each electric drive axle is provided with a set of wheels and corresponding motors and motor controllers on both sides, The system includes: a communication module configured to obtain a total requested torque at least according to a state signal of the vehicle; an electric drive axle identification module configured to determine the number of workable electric drive axles; a torque distribution module coupled to the The communication module and the electric drive axle identification module are configured to perform the method as described above.

According to another aspect of the present application, a vehicle is proposed, including: multiple sets of wheels, each set of wheels being coaxial; a battery pack system; a plurality of hub motors arranged on the wheels; and connected to two coaxial hub motors The electric drive axle; a sensor configured to obtain one or more of the vehicle speed, wheel speed, motor and/or temperature of the motor controller; multiple motor controllers, which are connected to the battery pack system, the multiple The in-wheel motor and the electric drive bridge are electrically connected, and are configured to control the in-wheel motor; and a processor, which is electrically connected to the plurality of motor controllers, the battery pack system, and the sensor, and executes the method described above.

According to another aspect of the present application, a storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the method described above is implemented.

The vehicle control method disclosed in the present application can distribute torque to each electric drive axle according to efficiency distribution, and can rotate the priority of each electric drive axle according to the mileage, so that the wear of the vehicle transmission system can be balanced.

Description of the drawings

Hereinafter, the preferred embodiments of the present invention will be described in further detail with reference to the accompanying drawings, in which:

Fig. 1 is a schematic diagram of a vehicle according to an embodiment of the present application;

Fig. 2 is a schematic diagram of the application of a vehicle control system according to an embodiment of the present application;

Fig. 3 is a schematic diagram of the application of torque control in a vehicle control system according to an embodiment of the present application;

Fig. 4 is a flow chart of a method for controlling a vehicle according to an embodiment of the present application;

Fig. 5 is a schematic block diagram of a vehicle control system according to an embodiment of the present application; and

Fig. 6 is a schematic diagram of a computer device of a vehicle in an embodiment according to an embodiment of the present application.

Detailed ways

In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

In the following detailed description, reference may be made to the various drawings of the specification that are part of this application to illustrate specific embodiments of the application. In the drawings, similar reference numerals describe substantially similar components in different drawings. Each specific embodiment of the present application is described in sufficient detail below, so that a person of ordinary skill with relevant knowledge and technology in the field can implement the technical solution of the present application. It should be understood that other embodiments may also be used or structural, logical or electrical changes may be made to the embodiments of the present application.

By adding a drive motor to the trailer, it can provide auxiliary driving force for the vehicle when driving, and can recover energy when braking. However, it is also necessary to consider the management and control of the torque output by the motors of each electric drive axle during long-term high-speed or special road driving to deal with the driving conditions of the vehicle and the special conditions that may occur during driving, so as to realize the multi-axis control of the vehicle. Reasonable and effective management of distributed electric drive axles. Among them, the driving conditions of the vehicle and the special circumstances that may occur while driving mainly include the following points:

1) The best efficiency output of the motor. In order to achieve high-efficiency utilization of electric energy during driving and high-efficiency recovery of energy during braking, in order to maximize the overall system efficiency, it is necessary to distribute the torque between the shafts of the multi-axis distributed electric drive axle under different conditions.

2) Unbalanced wear of the transmission system and wheels. In order to achieve the best efficiency distribution, several of the shafts are generally used as output shafts with larger torque. The transmission system and wheels of these shafts will be subject to greater wear. In the long run, it is easy to Abrasion loss balance leads to driving safety hazards.

3) Motor and electric control work over temperature. When the vehicle runs at high speed for a long time, the motor output power of some axles is higher, and it is more prone to over-temperature failure than other axles.

4) Malfunction of motor and electric control system. In the case of failure of one or several motors or controllers, yaw moment may be generated and the vehicle may be deflected, or even if the requested torque continues to be output, the system cannot meet the requirements for the best motor output efficiency.

5) Wheel slip or lock; the motor torque in the system continues to be distributed according to the best efficiency of the motor on low-attachment roads. Some motors output larger torque, and slip or lock-up is more likely to occur on low-attach roads.

The present application provides a multi-axis distributed electric drive axle control method and system. According to different states of the vehicle, the output priority of the electric drive axle is changed to ensure that the transmission system and the wheels are balanced, and according to the output priority of the electric drive axle The torque between the axles and wheels of each electric drive axle is distributed to ensure the best efficiency output of the motor. It can also limit the torque of each electric drive axle and redistribute it when the motor fails (failure or over temperature, etc.) or the vehicle is slipping on a special road, so as to ensure that the distributed electric drive axle can still follow The requested torque output of the vehicle controller, or at least to ensure the normal and safe driving of the vehicle.

In fact, the method of this application is not only applicable to trailers, but also applicable to other vehicles with multi-axis distributed electric drive axles. The following is only an example of a trailer.

The technical solution of the present application will be further described through specific implementations below. Those skilled in the art should understand that the following description is only for facilitating the understanding of the technical solutions of the present application, and should not be used to limit the protection scope of the present application.

Fig. 1 is a schematic diagram of a vehicle according to an embodiment of the present application. As shown in the figure, the multi-axis distributed electric drive axle control system is arranged on the trailer, and the multi-axis distributed electric drive axle control method of the present application can be applied to the control system shown in the figure. As understood by those skilled in the art, the multi-axis distributed electric drive axle control system and control method of the present application can also be applied to other types of trailers or other types of large vehicles such as trucks and buses. The following will take a trailer as an example to illustrate the technical solution of this application in detail:

As shown in the figure, a multi-axis distributed electric drive axle control system 100 (hereinafter referred to as "control system") is provided on the trailer, which includes: VCU 110 (Vehicle control unit, vehicle controller), multiple wheel hub motors 120, and The MCU 130 (motor controller) connected to the in-wheel motor 120. Wherein, the in-wheel motor 120 is arranged on the hub of the trailer wheel, and can provide driving force or braking force for the wheels of the trailer, so as to provide auxiliary driving or braking for the trailer; the MCU is connected to the corresponding in-wheel motor 120 and can be used for control Hub motor to achieve driving/braking.

In some embodiments, an electric drive axle 140 is included between the in-wheel motors 120 at both ends of the trailer. The two ends of the trailer are equipped with wheels and can be used to withstand the trailer’s load and maintain the trailer’s normal running on the road. Each end is driven by a hub motor controlled by an MCU. In some embodiments, the control system 100 may further include a battery pack system 150, which may be used to supply power to various components of the control system, and to recover the energy of the in-wheel motor when the vehicle is braking.

In some embodiments, the VCU can detect and identify the working drive axle in the control system; and can obtain the vehicle mileage, and according to the vehicle mileage and preset electric drive axle priority adjustment rules, the priority of the workable electric drive axle can be determined It can also obtain the total requested torque of the vehicle and the rotational speed of the hub motor of the workable electric drive axle. According to the total required torque, the rotational speed of the hub motor of the workable electric drive axle and the priority of the workable electric drive axle, the workable electric drive axle can be determined The corresponding distributed torque of the electric drive axle; the actual output torque of the workable electric drive axle can also be controlled according to the corresponding distributed torque of the workable electric drive axle. In some embodiments, a workable electric drive axle refers to an electric drive axle that can work normally. Specifically, the hub motors and MCUs at both ends of the electric drive axle can work normally, so that the electric drive axle can output torque and drive The wheel rotates or recovers energy.

Specifically, the VCU can parse the driver’s intentions (such as accelerator pedal, brake pedal, steering wheel angle, gear position, etc.) into requested driving power or braking power, and then use the hybrid energy distribution algorithm and the battery pack system to maximize Output limit, calculate the total request torque of the trailer multi-axle distributed electric drive axle control system, and distribute the torque to each electric drive axle according to the total request torque. In some embodiments, the VCU can also be installed on the tractor. In some embodiments, the VCU provided on the trailer can communicate with the tractor to obtain the driver's intention.

In some embodiments, the VCU may include a processor and a memory. The processor can include one or more central processing unit (CPU), graphics processing unit (GPU), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or a combination thereof. The processor can execute software or computer readable instructions stored in the memory to perform the methods or operations described herein. The processor can be implemented in several different ways. For example, the processor can include one or more embedded processors, processor cores, microprocessors, logic circuits, hardware finite state machines (FSM), digital signal processors (DSP), or combinations thereof. The memory can store software, data, logs, or a combination of them. The memory can be an internal memory or an external memory. For example, the memory can be volatile memory or non-volatile memory, such as non-volatile random access memory (NVRAM), flash memory, disk storage, or non-volatile memory such as static random access memory (SRAM). ) Of volatile memory.

In some embodiments, the VCU may also include a communication component, which can include one or more wired or wireless communication interfaces. For example, communication interface network interface card, wireless modem or cable modem. In one application, the communication interface can be a WiFi modem. In other applications, the communication interface can be a 3G, 4G, or 5G modem, an LTE modem, a Bluetooth component, a radio frequency receiver, an antenna, or a combination thereof.

The technical solution of the present application will be further illustrated by specific embodiments below:

Fig. 2 is an application schematic diagram of a vehicle control system according to an embodiment of the present application. As shown in the figure, first, the VCU obtains the status of each in-wheel motor, and through failure control (to exclude those electric drive axles that cannot work due to mechanical or electrical reasons), the number of workable electric drive axles m can be determined. A workable electric drive axle refers to an electric drive axle that can work normally. Generally, an electric drive axle is composed of a shaft, a matching hub motor and an MCU. The VCU detects the entire vehicle and identifies the vehicle's workable electric drive axle.

According to one embodiment, during the operation of the vehicle, the VCU can receive the operating status of the in-wheel motor from the MCU in real time, perform failure control according to the operating status of the in-wheel motor sent by the MCU, and identify the number m of electric drive axles that can be operated in the current system. When a certain wheel hub motor is detected to be faulty or not working, immediately turn off the wheel hub motor on the other side of the same electric drive axle, and the electric drive axle is regarded as damaged; or when a certain electric drive axle is detected In the event of a fault, immediately turn off the hub motors on both sides of the electric drive axle, and the electric drive axle is deemed damaged. Taking the system with 3 electric drive axles as a non-limiting example, when the hub motor on one side of the second electric drive axle fails and cannot operate, the VCU shuts down the hub motor on the other side of the second electric drive axle. And the VCU recognizes that the second electric drive axle of the current vehicle is not working, and the number of working electric drive axles is two, that is, the number of working electric drive axles is 2.

In some embodiments, the VCU failure control mechanism is as follows:

The normal working signal of the hub motor is "1", the failure signal is "0", the signal sequence on the left side of the multi-axis distributed drive axle is E _l , and the signal sequence on the right side is _Er , then the number of working electric drive axles is m and working The electric drive bridge sequence E are:

E=E _l ·E _r

Where · represents the multiplication of vector elements; T represents the transpose of the matrix.

Secondly, the VCU obtains the mileage of the vehicle, and can determine the priority of each workable electric drive axle based on the judgment of the working priority of the electric drive axle. In a multi-axis distributed electric drive axle control system, the torque of each workable electric drive axle is generally distributed based on efficiency, so that the torque distributed by each workable electric drive axle is not necessarily the same. Generally speaking, the larger the torque, the higher the priority. The electric drive axle with the largest torque is defined as the first priority electric drive axle, and the rest are arranged in order according to the torque. Because the electric drive axles with different priorities have different torques, the MCUs, in-wheel motors or wheels of the electric drive axles have different amounts of wear. In order to ensure that the amount of wear is as consistent as possible and improve the service life of the control system, it is necessary to work on each The priority of the electric drive axle is rotated.

In some embodiments, the mileage of the vehicle may refer to the accumulated mileage of the vehicle from the factory to the present, and the VCU can directly read this part of the data. In some embodiments, the VCU can also read the mileage of the vehicle from the ABS (antilock braking system). In some embodiments, the VCU can also read the vehicle mileage through TBOX (telematics box, car networking system), EBS (Electronic Brake Systems, electronic braking system), etc.

In some embodiments, the electric drive axle priority adjustment rule may be a preset rule, and the priority may be adjusted according to the mileage. For example, the priority of the electric drive axle can be adjusted based on a certain mileage threshold L, so that the transmission system and wheel wear can be balanced. As understood by those skilled in the art, the mileage threshold L can be set according to actual needs, for example, it can be set It is 100,000 kilometers, 50,000 kilometers, or 30,000 kilometers, etc. Taking the number of working electric drive axles in the system = 3 as an example, if there are three working electric drive axles A, B, C, assuming that the priority adjustment rule of electric drive axles is the mileage threshold for priority adjustment every 100,000 kilometers, Initially (that is, the mileage is 0 when leaving the factory), select A as the first priority working electric drive axle, B as the second priority working electric drive axle, and C as the third priority working electric drive Bridge; when the accumulated driving exceeds 100,000 kilometers, the priority is adjusted, B is adjusted to the first priority working electric drive axle, C is adjusted to the second priority working electric drive axle, and A is the third priority Class working electric drive axle; when the accumulated driving exceeds 200,000 kilometers, the priority adjustment is performed again, and C is adjusted to the first priority working electric drive axle, and A is adjusted to the second priority working electric drive axle. Adjust B to the third priority working electric drive bridge, and the subsequent operations can be deduced by analogy.

Then, according to an embodiment, the VCU may obtain or calculate the total requested torque _Treq of the vehicle and the current vehicle speed V, and according to the total requested torque _Treq , the number of workable electric drive axles, and the priority of the workable electric drive axles, based on the efficiency The total requested torque T _{req is} distributed to obtain the distributed torque T _i corresponding to each workable electric drive axle. In some embodiments, the total requested torque _Treq may be total driving torque or total braking torque. In some embodiments, the total requested torque of the vehicle can be sensed by the VCU of the user's (driver) operation intention, and the operation intention can be analyzed, and then the total requested torque can be calculated by the power distribution algorithm and the maximum output limit of the battery pack system. In some embodiments, the current vehicle speed V may be obtained from the ABS in the vehicle. In some embodiments, the current vehicle speed can also be obtained through an acceleration sensor or the rotational speed of a hub motor, or through a tractor, or through EBS or the like. In some embodiments, distributing the total requested torque based on efficiency is to obtain the torque distribution coefficient of each workable electric drive axle, and then obtain the corresponding distributed torque of each workable electric drive axle, so that the total efficiency of the control system is maximized. In some embodiments, since the ground adhesion is affected by the load, the bearing load of each workable electric drive axle is different, and the distribution of the ground adhesion force can also be used to obtain the distributed torque T _i corresponding to each workable electric drive axle. In some embodiments, even distribution may be used to obtain the distributed torque T _i corresponding to each workable electric drive axle.

In some embodiments, the total requested torque is allocated in the VCU based on the efficiency to obtain the allocated torque of each workable electric drive axle. The torque may be allocated according to the current vehicle speed V, the number of _{workable electric drive axles m, and the total requested torque T req} Look up the table to obtain the torque distribution coefficient k _{i of} each priority working electric drive axle. According to the torque distribution coefficient of each workable electric drive axle, the current distribution torque T _{i of} each workable electric drive axle can be obtained, so that the entire The overall efficiency of the control system is the highest. Among them, the preset torque distribution table can be constructed based on the best system efficiency equation set. The best system efficiency equation set can represent the speed of the hub motor in the electric drive axle, the total efficiency of the control system, the distributed torque of the electric drive axle, and the electric drive axle. Correspondence between efficiency. _{In some embodiments, the torque distribution coefficient k i of} each priority working electric drive axle can also be calculated in real time, so that the current distribution torque T _{i of} each workable electric drive axle can be obtained.

In some embodiments, the rotation speed of the in-wheel motor may be determined according to the current vehicle speed V. More specifically, the optimal system efficiency equations are as follows:

Note: T _i is the i th electric drive axle torque distribution; K _i for the i th electric transaxle requested torque with respect to the total proportion; [eta] _i is the i th electric transaxle efficiency; [eta] is the total efficiency of the _overall control system; _n-i Is the speed of the hub motor.

In some embodiments, the torque distribution table may be generated in advance. _{In some embodiments, the three-dimensional torque distribution table for the number of electric drive axles m, the rotation speed n i of the} hub motor, and the total requested torque _Treq can be calculated in real time, and each workable electric drive can be obtained in real time according to the driving state of the vehicle during the running of the vehicle. The torque of the drive axle accounts for the ratio k _i , so that the control system outputs with the highest efficiency.

Finally, after the distributed torque is issued to each working electric drive axle, the VCU will control the output torque of each working electric drive axle according to the current vehicle's operating state, which can more accurately control the torque of multiple working electric drive axles. In some embodiments, the operating state includes the state of the vehicle transmission system, the temperature of the MCU and the in-wheel motor during the operation of the electric drive axle, and the like. According to the real-time operating status of the vehicle, torque limiting control is performed on the workable electric drive axle to achieve more precise and reasonable control of the multi-axis distributed electric drive axle. In some embodiments, the output torque of the workable electric drive axle can also be directly controlled according to the distributed torque. For example, the output torque threshold value is preset for the output torque of the workable electric drive axle, and when the distributed torque exceeds the preset threshold value, the workable electric drive axle is directly output with reduced torque. In some embodiments, the control of the output torque of each workable electric drive axle may be to prevent problems in the workable electric drive axle before the distributed torque is issued to each working electric drive axle.

Specifically, in actual driving, when the output torque of a certain electric drive axle of the vehicle is too large, the vehicle may experience abnormal conditions such as sideslip and skidding; when the operating temperature of the transmission system in the vehicle is too high, the transmission system components may become irreversible. The damage situation; these situations all need to control the output torque of the workable electric drive axle. For example: when a working electric drive axle wheel slips under the assigned torque, it needs to be torque limited control to reduce its output torque to avoid slippage; when it is connected to a working electric drive axle MCU Or the in-wheel motor has a high operating temperature. If the torque output continues according to the assigned torque, the MCU or the in-wheel motor needs to be subjected to torque limiting control when the temperature is too high and the MCU or the in-wheel motor is irreversibly damaged to avoid the MCU or the in-wheel motor from burning. In some embodiments, the slip rate of the corresponding wheels of the workable electric drive axle can be calculated to determine whether the wheels are slipping, so that the torque limit control can be performed on the corresponding workable electric drive axle to make the wheels slip. The rate meets the preset threshold range to ensure the safety of driving.

In some embodiments, when the slip rate of the wheel corresponding to the highest priority workable electric drive axle is too large or the temperature of the in-wheel motor system is too high, its torque is limited, and the limited torque is compensated to Other non-highest priority working electric drive axles are used to ensure the total requested torque T _{req of the} control system. In some embodiments, the limited torque can be compensated to other non-highest priority workable electric drive axles, which can be allocated based on system efficiency or evenly allocated. In some embodiments, after other non-highest-priority workable electric drive axles receive the compensation torque, the slip rate of their wheels or the temperature of the in-wheel motor system also needs to be monitored to prevent excessive slip rate or the in-wheel motor The temperature of the system is too high, and the torque limit can be performed if necessary.

In some embodiments, when the non-highest priority workable electric drive axle has a corresponding wheel slip rate that is too large, it is considered that the highest priority workable electric drive axle also has a corresponding wheel slip rate that is too large. All workable electric drive axles have reduced torque output to ensure driving safety.

The following will describe in detail the control of the output torque of each working electric drive axle:

Fig. 3 is a schematic diagram of the application of torque control in a vehicle control system according to an embodiment of the present application.

As shown in the figure, the VCU can obtain the wheel speed and wheel speed in the workable electric drive axle; determine the wheel slip rate of the workable electric drive axle according to the wheel speed (or vehicle driving speed) and wheel speed; compare the wheel slip rate And the preset slip rate threshold range; when the wheel slip rate is less than the lower limit of the preset slip rate threshold range, the output torque of the workable electric drive axle is controlled according to the distributed torque of the workable electric drive axle; when the wheels are slipping When the shift rate is greater than the upper limit of the preset slip rate threshold range, limit the output torque of the workable electric drive axle so that the wheel slip rate is not greater than the upper limit of the preset slip rate threshold range; when the wheel slip rate is medium When it is between the upper limit and the lower limit of the preset slip rate range, compare the torque and the distributed torque of the current workable electric drive axle, and choose the smaller absolute value of the two as the output of the workable electric drive axle Torque helps to ensure that the wheel slip rate meets the change of the total requested torque within an appropriate range. For example: when the total requested torque needs to be reduced, the slip rate will decrease, and the possibility of slippage will decrease. The absolute value of the distributed torque is less than the absolute value of the current torque. The absolute value of the distributed torque can meet the change of the total requested torque. , And can also ensure that the slip rate is within the appropriate range; when the total requested torque needs to increase, the slip rate will increase, and the possibility of slippage will increase. The absolute value of the distributed torque is greater than the absolute value of the current torque, and the current torque The absolute value of, can ensure that the wheel slip rate is within an appropriate range and ensure driving safety.

In some embodiments, in order to prevent the multi-axle distributed electric drive axle from slipping/slipping when driving (accelerating), and locking (decelerating) the wheels when the vehicle is driving, the control system may prevent the dangerous situation of locking (deceleration). Through the monitoring and control of slip rate, the above situation can be prevented on different roads. The wheel slip rate is related to the rotational speed of the hub motor of the working electric drive axle and the wheel speed of the wheel. In practical applications, the VCU can be based on the rotational speed of the hub motor of the working electric drive axle provided by ABS and the wheel speed of the wheel provided by the MCU. To calculate the wheel slip rate, the specific calculation formula is as follows:

Among them: v _{x, W} is the wheel speed, ω _W is the wheel speed, r _W is the wheel rolling radius.

In some embodiments, the control strategy of the control system is as follows:

i. When

(Lower limit of slip rate), to maintain the distribution torque output;

ii. When a working electric drive axle corresponds to the wheel slip rate

(Upper limit of slip rate), the distributed torque of the workable electric drive axle is limited, so that the wheel slip rate is controlled at

Inside. When the vehicle enters a road with a high adhesion coefficient (slip rate

) Or the required torque is reduced (less than the torque limit shown in Figure 3), it can be switched to maintain the distributed torque output or output according to the required torque in time according to the slip rate;

iii. When

Compare the torque and the distributed torque of the current workable electric drive axle, and take the smaller absolute value of the two as the output torque of the workable electric drive axle.

For the first priority working electric drive axle, if the slip rate of the corresponding wheel exceeds

Through the torque reduction control of the workable electric drive axle, the wheel slip rate is controlled at

Inside. The reduced amount of distributed torque can be allocated to other workable electric drive axles with a level lower than the first priority. For workable electric drive axles lower than the first priority level, if the slip rate of the corresponding wheels exceeds

It is considered that the entire road conditions are relatively poor, and the overall workable electric drive axle is controlled to reduce the torque, so that the wheel slip rate is controlled at

Within, the torque reduction is no longer allocated to other workable electric drive axles.

In some embodiments, the output torque, the rotational speed of the hub motor of the workable electric drive axle, the wheel speed and other parameters can be simulated and calculated for multiple times to obtain the corresponding value when the wheel slip rate is not greater than the upper limit of the preset slip rate threshold range. Torque, use this value as the output torque after the torque limit, so as to meet the normal torque output required by the vehicle as much as possible on the premise of significantly reducing the risk of vehicle sideslip and rollover.

In some embodiments, the VCU can also obtain the real-time temperature of the in-wheel motor and MCU of the working electric drive axle. And according to the real-time temperature, the working electric drive axle is controlled by torque limiting, and the output torque of the working electric drive axle is controlled according to the corresponding distribution torque and the torque limiting control result of the working electric drive axle, so as to avoid the occurrence of the drive axle. In-wheel hub motor and/or MCU temperature is too high, causing transmission system failure.

In some embodiments, the temperature limit level can be determined, the preset torque limit range corresponding to the temperature limit level can be queried, and the torque limit range of the workable electric drive axle can be obtained by comparing the real-time temperature with the temperature limit level. , And control the output torque of the working electric drive axle. In some embodiments, the temperature limit level is positively correlated with the torque limit amplitude. For example, when the temperature limit level is level 1, the torque limit amplitude is 10%, and the working electric drive axle can allocate 90% of the corresponding torque. Perform torque output; when the temperature limit level is two, the torque limit range is 20%, and the working electric drive axle can output torque according to 80% of the corresponding distributed torque.

The following will use examples to describe the temperature-based torque limiting control process in detail:

The control strategy for MCU is:

When the temperature of a working electric drive axle MCU exceeds t1 (preset temperature), the torque output of the hub motors on both sides of the working electric drive axle is reduced, and the limit is 90% of the current distributed torque;

When the temperature of a working electric drive axle MCU exceeds t2 (preset temperature), the torque output of the hub motors on both sides of the working electric drive axle will be reduced, and the output will be 80% of the current distributed torque;

When the temperature of a workable electric drive axle MCU exceeds t3 (preset temperature), the workable electric drive axle MCU reports a fault and directly shuts off the output of the hub motors on both sides of the workable electric drive axle.

The control strategy for the in-wheel motor is:

When the temperature of the hub motor of a working electric drive axle exceeds t4 (preset temperature), the torque output of the hub motors on both sides of the working electric drive axle is reduced, and the output is 90% of the current distributed torque;

When the temperature of a hub motor of a workable electric drive axle exceeds t5 (preset temperature), the torque output of the hub motors on both sides of the workable electric drive axle is reduced, and the output is 80% of the current distributed torque;

When the temperature of a working electric drive axle hub motor exceeds t6 (preset temperature), report a fault to the working electric drive axle hub motor and/or MCU, and directly shut off the output of the hub motors on both sides of the working electric drive axle .

Similar to wheel slip rate control, for the first-priority workable electric drive axle, the torque reduction is evenly distributed (or based on efficiency) to other workable electric drive axles. For the workable electric drive axles of other priority levels, the torque reduction is no longer allocated.

In some embodiments, after the torque is limited according to the wheel slip rate control and the over-temperature prevention control, the torque is compared with the requested torque, and the limited requested torque is output to the MCU of each motor system.

The control system of the multi-axis distributed electric drive axle in the above-mentioned vehicle recognizes the workable electric drive axle in the multi-axis distributed electric drive axle, and obtains the workable electric drive according to the accumulated mileage of the vehicle and the priority adjustment rule of the workable electric drive axle. The priority of the axle, obtain the total requested torque of the vehicle and the rotational speed of the hub motor of the workable electric drive axle, and obtain the workable according to the total requested torque, the rotational speed of the hub motor of the workable electric drive axle, and the priority of the workable electric drive axle. The distributed torque corresponding to the electric drive axle is used to control the output torque of the workable electric drive axle. During the whole process, the priority of the workable electric drive axle can be changed according to the mileage of the vehicle, to ensure uniform wear of the transmission system and wheels, and to prevent slippage, hub motor/MCU overheating, etc., or in time for the above situations Adjust the output torque of the workable electric drive axle, so that the control of the multi-axis distributed electric drive axle in the vehicle can be realized reasonably and effectively.

Fig. 4 is a flowchart of a method for controlling a vehicle according to an embodiment of the present application.

As shown in the figure, in step 410, the total requested torque is obtained. The multi-axis distributed electric drive axle control system is generally used to provide auxiliary power to the vehicle or directly drive the vehicle. Therefore, it is necessary to obtain the auxiliary power of the vehicle or the total requested torque required to drive the vehicle in advance, and then distribute the total requested torque to multiple electric drive axles. In some embodiments, the total requested torque may be obtained according to the state signal of the vehicle. For example: the vehicle is in an accelerating or decelerating state, or the vehicle is in an uphill or downhill state, or the driver's (user) operation intention (accelerator pedal, brake pedal, steering wheel angle, gear position, etc.). In some embodiments, the total requested torque may also be calculated. For example: when the driver’s operation intention is sensed, the operation intention is analyzed, and then the total requested torque is obtained through the power distribution algorithm and the maximum output limit of the battery system. In some embodiments, the total requested torque may be total driving torque or total braking torque.

In step 420, it is determined that the electric drive bridge is operable. The multi-axis distributed electric drive axle is relative to the centralized electric drive axle. It includes multiple electric drive axles driven by in-wheel motors, and both ends of each electric drive axle are driven by a hub motor controlled by an MCU. , This kind of vehicle structure is generally suitable for large trucks or large passenger cars, and it has the characteristics of flexible control. Among them, the working electric drive axle refers to the electric drive axle that can work normally. Generally, the electric drive axle is composed of the shaft and the matching hub motor and MCU. The working electric drive axle refers to the shaft and the matching hub motor and MCU. It can work normally without damage. In some embodiments, the VCU can detect the entire vehicle and identify that the vehicle can work with an electric drive axle. In some embodiments, the VCU performs failure control according to the operating state of the in-wheel motor sent by the MCU by performing a failure judgment operation, and recognizes the number m of electric drive axles that can be operated by the current electric drive axle system. If the system has 3 electric drive axles, and the hub motor on one side of the second electric drive axle fails and cannot operate, the VCU turns off the wheel hub motor on the other side of the second electric drive axle, and the VCU recognizes that the current vehicle can work electric drive axle as 2 pieces.

In step 430, the priority of the workable electric drive bridge is determined. The multi-axis distributed electric drive axle system uses efficiency distribution to determine the distributed torque of the workable electric drive axle. Therefore, the distributed torque of different electric drive axles is not the same. The greater the distributed torque, the greater the wear of the wheels of the electric drive axle and the traditional system. In some embodiments, the priority of the workable electric drive axle can be adjusted to help balance the wear of the transmission system and the wheels. In some embodiments, the VCU obtains the mileage of the vehicle, can determine the priority of the workable electric drive axle according to the mileage, and can adjust the priority of the workable electric drive axle according to the mileage. In some embodiments, the priority of the electric drive axle can be adjusted based on a certain mileage. In some embodiments, the mileage can be set according to actual needs. For example: it can be 100,000 kilometers, 50,000 kilometers, or 30,000 kilometers. If there are three working electric drive axles A, B, C, assuming that the priority adjustment rule of the electric drive axle is to be adjusted once every 100,000 kilometers, then at the initial stage (that is, the mileage is 0 when leaving the factory), select A as the first Priority working electric drive axle, choose B as the second priority working electric drive axle, and choose C as the third priority working electric drive axle; when the accumulated driving exceeds 100,000 kilometers, adjust the priority and set B The working electric drive axle adjusted to the first priority will be adjusted, C will be adjusted to the second priority working electric drive axle, and A will be the third priority working electric drive axle; when the accumulated driving exceeds 200,000 kilometers, again Carry out priority adjustment, adjust C to the first priority working electric drive bridge, adjust A to the second priority working electric drive bridge, adjust B to the third priority working electric drive bridge, and follow-up operations to And so on.

In step 440, the distributed torque of the workable electric drive axle is determined. After obtaining the required total requested torque, the number of workable electric drive axles, and the priority of the workable electric drive axles, the total required torque needs to be allocated to workable electric drive axles with different priorities. In some embodiments, the distributed torque of each workable electric drive axle can be determined directly according to the priority of the workable electric drive axle and the total requested torque. For example: when there are 3 working electric drive axles, the working electric drive axle with the first priority is allocated 45% of the total requested torque, and the working electric drive axle with the second priority is allocated 35% of the total requested torque. The three-priority workable electric drive axle allocates 20% of the total requested torque. As understood by those skilled in the art, for different number of workable electric drive axles, the proportion of each workable electric drive axle to the total requested torque is not the same. Moreover, the proportion of each workable electric drive axle can be determined according to the actual situation.

In some embodiments, the torque of each workable electric drive axle can also be distributed based on efficiency. Further obtain the rotational speed of the hub motor of the workable electric drive axle, and according to the total requested torque, the rotational speed of the hub motor of the workable electric drive axle, and the priority of the workable electric drive axle, obtain the corresponding distributed torque of the workable electric drive axle, and It can be assigned to the corresponding workable electric drive axle, so that the overall efficiency of the vehicle control system can be the highest.

In some embodiments, determining the distributed torque of the workable electric drive axle may include obtaining a preset torque distribution table; and according to the preset torque distribution table, the total requested torque, the rotational speed of the hub motor of the workable electric drive axle, and the workable electric drive The priority of the bridge is derived from the assigned torque corresponding to the workable electric drive bridge. Among them, the preset torque distribution table is generated in advance, which can be constructed based on the optimal equation set of the total efficiency of the control system, and can be used to query according to the number of workable electric drive axles, the hub motor speed of the workable electric drive axle, and the total requested torque The torque distribution coefficient corresponding to each electric drive axle can be obtained, and the distribution torque coefficient of each workable electric drive axle can be correspondingly obtained under the highest overall efficiency of the control system, and then the distributed torque of each electric drive axle can be obtained. In some embodiments, the rotational speed of the in-wheel motor may be converted from the vehicle speed. Specifically, the optimal system efficiency equations are as follows:

In some embodiments, the three-dimensional torque distribution table of the number m of different working electric drive axles, the rotation speed n _{i of the} hub motor, and the total requested torque _Treq can be calculated in real time, and each workable electric drive can be obtained in real time according to the driving state of the vehicle during the driving process. The torque of the bridge occupies a ratio of k _i , so that the system outputs with the highest efficiency.

In some embodiments, the output torque of the workable electric drive axle is also controlled. In some embodiments, the output torque of the workable electric drive axle is controlled according to the assigned torque corresponding to the workable electric drive axle. In some embodiments, the torque output of the workable electric drive axle can be directly controlled according to the distributed torque. For example: when the distributed torque exceeds the preset output torque threshold, the distributed torque is directly reduced. In some embodiments, the multi-axis distributed electric drive axle can also be controlled more accurately according to the running state of the vehicle (slip rate or temperature). For example: when the vehicle enters a low adhesion road, the electric drive axle is reduced; or when the wheels are slipping, skidding, etc., the electric drive axle is reduced; or when the hub motor/MCU temperature is too high, the electric drive axle is reduced. The drive axle is twisted down.

In some embodiments, controlling the distributed torque of the workable electric drive axle may include obtaining the operating state of the vehicle; and performing torque limit control on the workable electric drive axle according to the vehicle operating state, and according to the corresponding distributed torque of the workable electric drive axle As well as the torque limit control result, the output torque of the workable electric drive axle is controlled.

In some embodiments, the vehicle operating state includes the state of the vehicle transmission system, the temperature of the MCU and the in-wheel motor during the operation of the electric drive axle, and the like. According to the real-time operating status of the vehicle, the working electric drive axle is controlled by torque limiting, so as to realize more precise and reasonable control of the multi-axis distributed electric drive axle. Specifically, in practical applications, when the output torque of a certain electric drive axle of the vehicle is too large, the vehicle may have abnormal sideslip or skidding; or when the operating temperature of the transmission system in the vehicle is too high, transmission system components may appear Irreversible damage conditions; these conditions require the control of the output torque of the electric drive axle. In some embodiments, when the wheels of a certain electric drive axle are expected to slip under the distributed torque, they also need to be subjected to torque limit control to reduce their output torque to avoid slippage; The connected MCU or hub motor is expected to run at a higher temperature under the distributed torque. If the output torque continues to be output according to the distribution, the temperature will be too high, causing irreversible damage to the MCU or hub motor. Torque limiting control is required to reduce its output torque to avoid The MCU or the hub motor is burned out.

In some embodiments, torque limit control can be performed on the workable electric drive axle according to the operating state of the vehicle, and the output torque of the workable electric drive axle can be controlled according to the assigned torque corresponding to the workable electric drive axle and the torque limit control result. Including: obtain the wheel speed and wheel speed of the workable electric drive axle according to the vehicle running state; determine the wheel slip rate of the workable electric drive axle according to the wheel speed and wheel speed; compare the wheel slip rate with the preset slip rate The range of the threshold. When the wheel slip rate is less than the lower limit of the preset slip rate threshold range, the output torque of the multi-axis distributed electric drive axle is controlled according to the assigned torque corresponding to the workable electric drive axle; when the wheel slip rate is greater than the preset At the upper limit of the slip rate threshold range, reduce the output torque of the workable electric drive axle so that the wheel slip rate is not greater than the upper limit of the preset slip rate threshold range; when the wheel slip rate is at the preset slip rate When the shift rate threshold range is between the upper limit and the lower limit, compare the current torque and the distributed torque of the workable electric drive axle, and choose the smaller absolute value of the two to control the output torque of the multi-axis distributed electric drive axle .

In one of the embodiments, when the wheel slip rate is greater than the upper limit of the preset slip rate threshold range, the output torque of the workable electric drive axle is reduced so that the wheel slip rate is not greater than the preset slip rate threshold range The upper limit includes: when the wheel slip rate corresponding to the target workable electric drive axle is greater than the upper limit of the preset slip rate threshold range, reduce the distributed torque of the target workable electric drive axle so that the target workable electric drive axle corresponds The wheel slip rate is not greater than the upper limit of the preset slip rate threshold range. The target workable electric drive axle includes the highest priority workable electric drive axle; the allocated torque reduced by the target workable electric drive axle is allocated to other workable electric drive axles. Work the electric drive axle to get the updated distribution torque of other workable electric drive axles. In some embodiments, determine the wheel slip rate of other workable electric drive axles under the updated distributed torque; perform torque limiting on other workable electric drive axles according to the obtained wheel slip rate to make the latest wheel slip Rate is not greater than the upper limit of the preset slip rate threshold range. In some embodiments, the reduced distribution torque of other workable electric drive axles is not shared with other workable electric drive axles of lower priority. In some embodiments, the apportionment may be direct apportionment (and evenly apportioned to each other workable electric drive axle) or may be based on efficiency to other workable electric drive axles.

The specific wheel slip rate calculation formula and the slip rate torque limiting control process can refer to the embodiment of FIG. 3, which will not be repeated here.

In some embodiments, performing torque limiting control on the workable electric drive axle according to the vehicle operating state, and controlling the output torque of the workable electric drive axle according to the assigned torque corresponding to the workable electric drive axle and the torque limiting control result includes : Obtain the real-time temperature of the in-wheel motor and MCU of the working electric drive axle according to the vehicle operating state; perform torque limit control on the working electric drive axle according to the real-time temperature, and according to the corresponding distribution torque and torque limit of the working electric drive axle Amplitude control results, control the output torque of the workable electric drive axle.

In some embodiments, the real-time temperature of the hub motor and MCU of the workable electric drive axle is obtained according to the operating state of the vehicle; the torque limit control is performed on the workable electric drive axle according to the real-time temperature, and the working electric drive axle corresponds to Distributing torque and torque limiting control results, and controlling the output torque of the workable electric drive axle include:

When the real-time temperature of the hub motor or MCU corresponding to the target workable electric drive axle is too high, reduce the distributed torque of the target workable electric drive axle, so that the real-time temperature of the wheel hub motor or MCU corresponding to the target workable electric drive axle is reduced, and the target can be The working electric drive axle includes the highest priority working electric drive axle; the allocated torque reduced by the target working electric drive axle is allocated to other working electric drive axles, and the updated distribution torque of other working electric drive axles is obtained. In some embodiments, determine the real-time temperature of the hub motor or MCU under the updated distributed torque of other workable electric drive axles; perform torque limiting on other workable electric drive axles according to the obtained real-time temperature to prevent the latest real-time temperature from overshooting high. In some embodiments, the reduced distributed torque of other workable electric drive axles is not shared with other workable electric drive axles of lower priority. In some embodiments, the apportionment may be direct apportionment (and evenly apportioned to each other workable electric drive axle) or may be based on efficiency to other workable electric drive axles.

For specific temperature-based torque limiting control, please refer to the embodiment in FIG. 3, which will not be repeated here.

Fig. 5 is a schematic block diagram of a vehicle control system according to an embodiment of the present application. The system includes:

The communication module 510 is configured to obtain the total requested torque according to the state signal of the vehicle and/or the driver's intention;

The electric drive axle identification module 520 is used to identify the workable electric drive axle in the multi-axis distributed electric drive axle;

The torque distribution module 530 is coupled with the communication module and the electric drive axle identification module, and can be used to obtain the distributed torque of the workable electric drive axle.

In some embodiments, the torque distribution module 530 may also determine the priority of the operable electric drive axle. In some embodiments, the torque distribution module 530 may obtain the mileage of the vehicle, and adjust the rules according to the accumulated mileage of the vehicle and the preset axle priority, so as to obtain the priority of the workable electric drive axle. In some embodiments, the torque distribution module 530 may obtain the total requested torque of the vehicle and the rotational speed of the hub motor of the workable electric drive axle, and according to the total requested torque, the rotational speed of the hub motor of the workable electric drive axle, and the priority of the workable electric drive axle Level to obtain the distributed torque of the workable electric drive axle.

In some embodiments, the torque distribution module 530 can also be used to obtain a preset torque distribution table; according to the preset torque distribution table, the total requested torque, the rotational speed of the hub motor of the workable electric drive axle, and the priority of the workable electric drive axle , Obtain the distributed torque corresponding to the workable electric drive axle. Among them, the preset torque distribution table is constructed based on the efficiency optimal equation set.

In some embodiments, the torque distribution module 530 may also be used to control the output torque of the workable electric drive axle according to the distribution torque of the workable electric drive axle. In some embodiments, the torque distribution module 530 further includes a method for acquiring the operating state of the vehicle; performing torque limiting control on the workable electric drive axle according to the vehicle operating state, and according to the corresponding distribution torque and torque limiting of the workable electric drive axle The control result is to control the output torque of the workable electric drive axle.

In some embodiments, the torque distribution module 530 may also be used to obtain the wheel speed and wheel speed of the workable electric drive axle according to the vehicle operating state; and determine the wheel slip rate of the workable electric drive axle according to the wheel speed and wheel speed. ; According to the comparison between the wheel slip rate and the preset slip rate threshold range, the output torque of the multi-axis distributed electric drive axle is controlled.

In some embodiments, the torque distribution module 530 may also be used to reduce the distributed torque of the target workable electric drive axle when the wheel slip rate corresponding to the target workable electric drive axle is greater than the upper limit of the preset slip rate threshold range, In order that the wheel slip rate corresponding to the target workable electric drive axle is not greater than the upper limit of the preset slip rate threshold range, the target workable electric drive axle includes the workable electric drive axle with the highest priority. The allocated torque reduced by the target workable electric drive axle is allocated to other workable electric drive axles that are not of the highest priority, and the other workable electric drive axles update the allocated torque according to the obtained torque.

In some embodiments, the torque distribution module 530 can also be used to reduce the overall workable electric drive when the wheel slip rate corresponding to the other workable electric drive axle with a non-highest priority is greater than the upper limit of the preset slip rate threshold range. The torque of the axle is distributed so that the wheel slip rate corresponding to the workable electric drive axle is not greater than the upper limit of the preset slip rate threshold range. Among them, the reduced distribution torque is not apportioned.

In some embodiments, the torque distribution module 530 can also be used to obtain the real-time temperature of the motor and the motor controller of the workable electric drive axle according to the operating state of the vehicle; perform torque limiting control on the workable electric drive axle according to the real-time temperature, And according to the distribution torque corresponding to the workable electric drive axle and the torque limiting control result, the output torque of the workable electric drive axle is controlled.

The control system of the multi-axis distributed electric drive axle in the above-mentioned vehicle recognizes the workable electric drive axle in the multi-axis distributed electric drive axle, and obtains the workable electric drive axle according to the accumulated mileage of the vehicle and the preset axle priority adjustment rules To obtain the total requested torque of the vehicle and the motor speed of the workable electric drive axle, and obtain the workable electric drive axle according to the total requested torque, the motor speed of the workable electric drive axle and the priority of the workable electric drive axle The corresponding distribution torque is used to control the output torque of the workable electric drive axle. During the whole process, the priority of the workable electric drive axle can be changed according to the vehicle mileage to ensure uniform wear of the transmission system and wheels, and the control of the multi-axis distributed electric drive axle in the vehicle can be realized reasonably and effectively.

For the specific definition of the control system of the multi-axis distributed electric drive axle in the vehicle, please refer to the above definition of the control method of the multi-axis distributed electric drive axle in the vehicle, which will not be repeated here. The various modules in the control system of the multi-axis distributed electric drive axle in the above-mentioned vehicle can be implemented in whole or in part by software, hardware, and a combination thereof. The above-mentioned modules may be embedded in the form of hardware or independent of the processor in the computer equipment, or may be stored in the memory of the computer equipment in the form of software, so that the processor can call and execute the operations corresponding to the above-mentioned modules.

Fig. 6 is a schematic diagram of a computer device of a vehicle in an embodiment according to an embodiment of the present application. As shown in the figure, the computer device may be a server, and its internal structure diagram may be as shown in FIG. 6. The computer equipment includes a processor, a memory, and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide calculation and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The computer equipment database is used to store historical vehicle driving status, vehicle torque output and other data. The network interface of the computer device is used to communicate with an external terminal through a network connection. The computer program is executed by a processor to realize a control method of a multi-axis distributed electric drive axle in a vehicle.

Those skilled in the art can understand that the structure shown in FIG. 6 is only a block diagram of part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may Including more or fewer parts than shown in the figure, or combining some parts, or having a different arrangement of parts.

In some embodiments, a vehicle is provided, which mainly includes a trailer. The trailer is configured to provide auxiliary power to the tractor or recover braking energy, and it includes a plurality of auxiliary electric drive axles, specifically including a battery pack system and an in-wheel motor, and an electric drive axle coupled with the in-wheel motor; a processor; And a motor controller coupled with the processor. The processor is respectively electrically connected to the motor controller and the battery pack system, and executes the steps in the above method embodiment. In some embodiments, the vehicle may further include a sensor, which may be used to obtain one or more of the vehicle speed, the wheel rotation speed, and the temperature of the hub motor/motor controller.

In some embodiments, a computer-readable storage medium is provided, on which a computer program is stored, and the computer program is executed by a processor to implement the steps in the foregoing method embodiments.

The trailer multi-axle distributed electric drive axle control system and control method proposed in this application balance the wear of the traditional system and wheels by rotating the priority of each workable electric drive axle, and it can also adjust the wheel slip rate and The torque management control mechanism of over-temperature detection enables the vehicle to cope with the complex working conditions in actual driving, and to ensure the safety of the vehicle, and to distribute the torque between the axles and the wheels of the multi-axle distributed drive axle under different conditions , In order to ensure the best efficiency output of the electrode.

The above-mentioned embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. Those of ordinary skill in the relevant technical fields can also make various changes and modifications without departing from the scope of the present invention. Therefore, all The equivalent technical solutions should also belong to the scope of the disclosure of the present invention.

Claims

A method for controlling a vehicle, wherein the vehicle includes a plurality of electric drive axles, each electric drive axle is provided with a set of wheels and corresponding motors and motor controllers on both sides, wherein the method includes:

Obtain the total requested torque at least according to the state signal of the vehicle;

Determining the number of workable electric drive bridges in the electric drive bridge;

Determine the priority of the workable electric drive axle at least according to the mileage that the vehicle has traveled; and

The assigned torque corresponding to the workable electric drive axle is determined at least according to the priority of the workable electric drive axle and the total requested torque.
The control method according to claim 1, further comprising determining whether to limit the distributed torque when outputting at least according to the slip rate of the wheel of the vehicle or the temperature of the motor/motor controller.
The control method according to claim 1, wherein determining the priority of the workable electric drive axle at least according to the mileage that the vehicle has traveled comprises:

According to the accumulated mileage of the vehicle and the preset priority adjustment rule, when the preset mileage threshold is reached, the priority order of the workable electric drive axle is adjusted.
The control method according to claim 1, further comprising:

Obtain the motor speed of the working electric drive axle; and

Under the premise that the total efficiency of the vehicle system is maximized, the workable electric drive axle is obtained at least according to the total requested torque, the motor speed of the workable electric drive axle, and the priority of the workable electric drive axle Corresponding distribution torque.
3. The control method according to claim 2, wherein determining whether to limit the distributed torque at least according to the slip rate of the vehicle comprises:

Obtain the running speed of the vehicle and the wheel speed of each set of wheels; and

Determine the wheel slip rate of each group of wheels at least according to the operating speed and the wheel rotation speed;

Comparing the wheel slip rate with a preset slip rate threshold range;

When the wheel slip rate is less than the lower limit of the preset slip rate threshold range, the output does not need to limit the distributed torque of the corresponding workable electric drive axle;

When the wheel slip rate is greater than the upper limit of the preset slip rate threshold range, it is necessary to limit the distributed torque of the corresponding workable electric drive axle when outputting.
The control method according to claim 5, wherein when the wheel slip rate falls within the preset slip rate threshold range, the assigned torque of the corresponding workable electric drive axle is combined with the absolute value of its current torque The smaller one is used as output.
The control method according to claim 5, wherein when the wheel slip rate is greater than the upper limit of the preset slip rate threshold range, the output torque of the corresponding workable electric drive axle needs to be limited. The amplitude of is required to satisfy that the wheel slip rate is not greater than the upper limit of the preset slip rate threshold range.
The control method according to claim 5 or 7, wherein when the wheel slip rate is greater than the upper limit of the preset slip rate threshold range, the output torque needs to be allocated to the corresponding workable electric drive axle Limiting, including:

For the first-priority workable electric drive axle, when its corresponding wheel slip rate is greater than the upper limit value, reduce its distributed torque; and

The allocated torque reduced by the first priority workable electric drive axle is allocated to other priority workable electric drive axles.
The control method according to claim 8, wherein:

When the wheel slip rate corresponding to one or more other workable electric drive axles is also greater than the upper limit of the preset slip rate threshold range, the reduced distributed torque for the first priority workable electric drive axle is not Then make an apportionment; and

The distribution torque of the other workable electric drive axle is limited to satisfy that the corresponding wheel slip rate is not greater than the upper limit of the preset slip rate threshold range.
3. The control method according to claim 2, wherein determining whether the distributed torque needs to be limited at least according to the temperature of the vehicle comprises:

Obtaining the temperature of the motor and/or the motor controller corresponding to the workable electric drive bridge; and

According to the degree to which the temperature exceeds the preset temperature threshold, the distributed torque of the corresponding workable electric drive axle is correspondingly limited.
A vehicle control system, wherein the vehicle includes a plurality of electric drive axles, each electric drive axle is provided with a set of wheels and corresponding motors and motor controllers on both sides, the system includes:

A communication module configured to obtain the total requested torque at least according to the state signal of the vehicle;

An electric drive axle identification module, which is configured to determine the number of workable electric drive axles;

A torque distribution module, coupled to the communication module and the electric drive axle identification module, and configured to perform the method of any one of claims 1-10.
A means of transportation including:

Multiple sets of wheels, each set of wheels is coaxial;

Battery pack system;

Multiple hub motors, their settings and the wheels;

Electric drive axle connected with two coaxial hub motors;

The sensor is configured to obtain one or more of the vehicle speed, wheel speed, motor and/or temperature of the motor controller;

A plurality of motor controllers, which are electrically connected to the battery pack system, the plurality of in-wheel motors, and an electric drive axle, and are configured to control the in-wheel motors; and

The processor is electrically connected to the plurality of motor controllers, the battery pack system, and the sensor, and executes the method according to any one of claims 1-10.
A storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method described in any one of claims 1-10 is implemented.