CN116278806A - Electric vehicle torque distribution method, system, electronic equipment and storage medium - Google Patents

Electric vehicle torque distribution method, system, electronic equipment and storage medium Download PDF

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Publication number
CN116278806A
CN116278806A CN202310346082.4A CN202310346082A CN116278806A CN 116278806 A CN116278806 A CN 116278806A CN 202310346082 A CN202310346082 A CN 202310346082A CN 116278806 A CN116278806 A CN 116278806A
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China
Prior art keywords
vehicle
speed
slip
wheel
rate
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CN202310346082.4A
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Chinese (zh)
Inventor
白强
杜向斌
钟川
严钦山
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Chongqing Changan New Energy Automobile Technology Co Ltd
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Chongqing Changan New Energy Automobile Technology Co Ltd
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Priority to CN202310346082.4A priority Critical patent/CN116278806A/en
Publication of CN116278806A publication Critical patent/CN116278806A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/20—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L15/00—Methods, circuits, or devices for controlling the traction-motor speed of electrically-propelled vehicles
    • B60L15/32—Control or regulation of multiple-unit electrically-propelled vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/10—Indicating wheel slip ; Correction of wheel slip
    • B60L3/106—Indicating wheel slip ; Correction of wheel slip for maintaining or recovering the adhesion of the drive wheels
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/10—Vehicle control parameters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/10—Vehicle control parameters
    • B60L2240/12—Speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/42—Drive Train control parameters related to electric machines
    • B60L2240/423—Torque
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Arrangement And Driving Of Transmission Devices (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

The invention provides a torque distribution method of an electric vehicle, comprising the following steps: s1, S2, S3 and S4. S1, setting a speed threshold value, a wheel rotation speed change rate threshold value and a vehicle slip rate threshold value according to a vehicle; s2, collecting vehicle running data, and calculating the actual rotation speed change rate of wheels and the actual slip rate of the vehicle according to the vehicle running data; s3, comparing the calculated actual rotation speed change rate of the wheels with the actual slip rate of the vehicle, a wheel rotation speed change rate threshold value and a vehicle slip rate threshold value to obtain the running vehicle condition of the vehicle; s4, distributing the torque occupancy rate of the front wheels and the rear wheels of the vehicle according to the running vehicle condition and the actual slip rate of the vehicle. The electric vehicle torque distribution method can realize the calculation of the slip rate and distribute the torque output based on the slip rate so as to realize the rapid escape of the vehicle.

Description

Electric vehicle torque distribution method, system, electronic equipment and storage medium
Technical Field
The present invention relates to the field of automotive technologies, and in particular, to a method and a system for distributing torque of an electric vehicle, an electronic device, and a storage medium.
Background
With the technical development of new energy automobiles, the new energy automobile market is exploded, and the electric four-wheel drive control is faster and finer than the traditional four-wheel drive control, so that good market satisfaction is obtained. Meanwhile, due to the quick response of the motor, higher requirements are also put on a control system. For example, when the system monitors slip during a pull-out and low-accessory large throttle launch, the TCS is now experiencing a torque-down demand and is very susceptible to a clunk during this transition. The common slip ratio distribution logic is to calculate the slip ratio based on the difference between the wheel speed and the reference vehicle speed, and then to distribute the front and rear axle torque according to the slip ratio.
However, in the underlying software, the calculated speed of the wheel speed is far lower than the calculated speed of the motor rotation speed, for example, the transmission ratio of the motor to the wheel is 10, and one turn of the wheel corresponds to 10 turns of the motor, which means that the number of PWM signals obtained by the motor rotation speed calculation module is 10 times that of the wheel speed calculation module in the same time, the effective motor rotation speed signals can be sent out quickly, and the effective wheel speed signals can be delayed for a period of time, for example, in fig. 1, when a certain vehicle type starts, the motor rotation speed is compared with the vehicle speed, the delay time of the vehicle speed is longer, and as a result, the slip and the slip condition can be judged only after the slip and the slip are generated, the slip and the delay is larger, so that the problems of poor NVH effect, low-attachment starting and the like of the whole vehicle are caused.
In the prior art (CN 111731109 a), a method for distributing torque of an automobile is disclosed, but there is no analysis and calculation on the slip rate and the speed change rate of the automobile, and there is no consideration on the slip rate and the torque distribution of the automobile, so that the torque distribution cannot be normally distributed under the slip condition, and poor driving experience is brought.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a torque distribution method for an electric vehicle, which is used for identifying skidding of an electric four-wheel drive new energy automobile on a low-attachment road surface, and controlling torque output and four-wheel drive distribution on the basis of the identified skidding so as to achieve rapid escape.
The invention provides a torque distribution method of an electric vehicle, comprising the following steps:
s1: setting a speed threshold value, a wheel rotation speed change rate threshold value and a vehicle slip rate threshold value according to a vehicle;
s2: collecting vehicle running data, and calculating the actual rotation speed change rate of wheels and the actual slip rate of the vehicle according to the vehicle running data;
s3: comparing the calculated actual rotation speed change rate of the wheels with the actual slip rate of the vehicle, the threshold value of the rotation speed change rate of the wheels and the threshold value of the slip rate of the vehicle to obtain the running condition of the vehicle;
s4: and distributing the torque occupancy rate of the front wheels and the rear wheels of the vehicle according to the running vehicle condition and the actual slip rate of the vehicle.
In one embodiment of the invention, the vehicle speed threshold value is a value in the range of 6-10km/h, and is related to the vehicle speed when the low-accessory road surface large throttle starts to have a bump; the wheel speed change rate threshold is determined according to a maximum wheel speed change rate of the vehicle in a non-slip state, and the vehicle slip rate threshold is determined according to a maximum vehicle slip rate of the vehicle in a non-slip state.
In one embodiment of the present invention, in the S2, the vehicle traveling data includes a vehicle displacement speed and a wheel rotation speed, the vehicle displacement speed is obtained by a velocimeter provided at a bottom of the vehicle, and the wheel rotation speed is calculated by a corresponding vehicle motor rotation speed of the vehicle and a wheel radius of a corresponding wheel.
In one embodiment of the present invention, in the step S2, the wheel rotation speed is calculated by: wheel rotational speed = vehicle motor rotational speed x wheel radius x 0.377/ratio, where ratio is the transmission ratio of the respective motor to the respective wheel of the vehicle.
In one embodiment of the present invention, in S2, a front wheel displacement slip ratio, a front wheel speed slip ratio, a rear wheel displacement slip ratio, and a rear wheel speed slip ratio are obtained from the vehicle displacement speed and the wheel rotation speed, respectively, and the maximum value of the front wheel displacement slip ratio and the front wheel speed slip ratio is taken as a front wheel slip ratio, and the maximum value of the rear wheel displacement slip ratio and the rear wheel speed slip ratio is taken as a rear wheel slip ratio.
In one embodiment of the present invention, in S2, the wheel rotation speed includes a front wheel speed and a rear wheel speed, wherein a vehicle displacement speed is a first reference vehicle speed, a smaller value of the front wheel speed and the rear wheel speed is a second reference vehicle speed, the front wheel speed is an average value of a front left wheel speed and a front right wheel speed of the vehicle, and the rear wheel speed is an average value of a rear left wheel speed and a rear right wheel speed of the vehicle.
In one embodiment of the present invention, the front wheel displacement slip ratio= |first reference vehicle speed-front wheel speed|/front wheel speed, the front wheel rotation slip ratio= |second reference vehicle speed-front wheel speed|/front wheel speed, the rear wheel displacement slip ratio= |first reference vehicle speed-rear wheel speed|/rear wheel speed, and the rear wheel rotation slip ratio= |second reference vehicle speed-rear wheel speed|/rear wheel speed.
In one embodiment of the present invention, in the S2, the vehicle actual slip ratio includes the front wheel slip ratio and the rear wheel slip ratio, and the rotational speed change rate is obtained by calculating a change rate of the wheel rotation speed per unit time.
In one embodiment of the present invention, in S3, the vehicle is started when the vehicle speed is less than the vehicle speed threshold, the vehicle is slipped when the actual wheel speed change rate is greater than the wheel speed change rate threshold, and the vehicle is slipped when the actual vehicle slip rate is greater than the vehicle slip rate threshold.
In one embodiment of the present invention, in S4, torque is distributed according to a slip condition of the front wheels and the rear wheels of the vehicle, and when the front wheels are in the slip condition, torque is distributed to the rear axle of the vehicle according to the magnitude of the slip ratio of the front wheels; and when the rear wheels are in the skidding vehicle condition, distributing torque to a front axle of the vehicle according to the slip rate of the rear wheels.
The present invention also provides an electric vehicle torque distribution system comprising:
and the acquisition module is used for: the acquisition module acquires vehicle running data, wherein the vehicle running data comprises a vehicle displacement speed and a wheel rotation speed;
the processing module is used for: processing the vehicle running data to obtain a front wheel slip ratio and a rear wheel slip ratio;
the distribution module: comparing the front wheel slip rate and the rear wheel slip rate with a vehicle slip rate threshold value, judging whether wheel slip occurs, and distributing the torque occupation proportion of the front wheels and the rear wheels according to the sizes of the front wheel slip rate and the rear wheel slip rate.
In one embodiment of the present invention, the front wheel slip ratio in the processing module includes a front wheel slip ratio and a front wheel speed slip ratio, the rear wheel slip ratio includes a rear wheel slip ratio and a rear wheel speed slip ratio, a maximum value of the front wheel slip ratio and the front wheel speed slip ratio is taken as the front wheel slip ratio, and a maximum value of the rear wheel slip ratio and the rear wheel speed slip ratio is taken as the rear wheel slip ratio.
In one embodiment of the invention, the distribution module wherein the vehicle slip rate threshold is determined based on historical data collected by the collection module.
The present invention also provides an electronic device including:
one or more processors;
storage means for storing one or more programs that, when executed by the one or more processors, cause the electronic device to implement the method of any of the preceding claims.
The invention also provides a computer readable storage medium, characterized in that it has stored thereon a computer program which, when executed by a processor of a computer, causes the computer to perform the method of any of the above.
The invention provides an electric vehicle torque distribution method, an electric vehicle torque distribution system, an electronic device and a storage medium, which can realize calculation of a vehicle slip rate and a speed change rate.
Further, according to the torque distribution method, the vehicle condition is judged according to the calculated vehicle slip rate and the calculated speed change rate, and the torque distribution is carried out according to the slip rate.
The torque distribution method can quickly identify the situation of the slipping vehicle and intelligently distribute the torque duty ratio, so that the slipping vehicle can quickly get rid of the problem.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of the steps of the method of the present invention;
FIG. 2 is a flow chart of an embodiment of the present invention;
FIG. 3 is a graph showing the motor speed, wheel speed and torque output by the motor when the vehicle is running normally in an embodiment of the present invention;
fig. 4 is a graph showing changes in motor speed, wheel speed and torque output by the motor when the vehicle is slipping in one embodiment of the present invention.
Fig. 5 is a system architecture diagram of the system of the present invention.
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict. It is also to be understood that the terminology used in the examples of the invention is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the invention. The test methods in the following examples, in which specific conditions are not noted, are generally conducted under conventional conditions or under conditions recommended by the respective manufacturers.
Please refer to fig. 1 to 5. It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the invention to the extent that it can be practiced, since modifications, changes in the proportions, or otherwise, used in the practice of the invention, are not intended to be critical to the essential characteristics of the invention, but are intended to fall within the spirit and scope of the invention. Also, the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like recited in the present specification are merely for descriptive purposes and are not intended to limit the scope of the invention, but are intended to provide relative positional changes or modifications without materially altering the technical context in which the invention may be practiced.
The invention provides a torque distribution method for an electric vehicle, which can realize the calculation of a slip rate and distribute torque output based on the slip rate so as to realize the rapid escape of the vehicle. Specifically, the electric vehicle torque distribution method of the present invention includes: s1, S2, S3 and S4. S1, setting a speed threshold value, a wheel rotation speed change rate threshold value and a vehicle slip rate threshold value according to a vehicle; s2, collecting vehicle running data, and calculating the actual rotation speed change rate of the wheels and the actual slip rate of the vehicles according to the rear wheel speed vehicle running data; s3, comparing the calculated actual rotation speed change rate of the rear wheel speed wheels, the actual slip rate of the rear wheel speed vehicles with a rear wheel speed wheel rotation speed change rate threshold value and a rear wheel speed vehicle slip rate threshold value to obtain vehicle running conditions; s4, distributing the torque occupancy rate of the front wheels and the rear wheels of the vehicle according to the wheel speed running condition of the rear wheels and the actual slip rate of the vehicle.
As shown in fig. 1, the torque distribution method in the present case includes four steps, namely: setting various thresholds in S1, collecting running data in S2, calculating the actual rotation speed change rate and the actual slip rate according to the running data, comparing the actual rotation speed change and the actual slip rate with the thresholds in S3 to obtain running vehicle conditions, and distributing the torque of the front wheels and the rear wheels according to the running vehicle conditions and the S4 actual slip rate.
As shown in fig. 2, the actual vehicle speed of the vehicle is first ensured to be smaller than the preset vehicle speed, which is set to 100km/h in the present embodiment, and then the determination of the slip vehicle condition is performed. After the speed of the vehicle is ensured to be smaller than the preset speed of the vehicle, the speed change rate of the vehicle, the wheel speed slip rate and the vehicle displacement slip rate are calculated respectively. And when the change rate of the rotation speed of the vehicle or the displacement and slip rate of the vehicle is larger than a preset value, determining that the vehicle is in a slipping vehicle condition. At the moment, the vehicle reduces the torque rising gradient, takes the maximum value of the wheel rotation speed slip rate and the vehicle displacement slip rate as the actual slip rate of the vehicle, and determines the torque distribution coefficient according to the actual slip rate of the vehicle.
As shown in fig. 1 and 2, in step S1, three thresholds, that is, a vehicle speed threshold, a rotational speed change rate threshold, and a slip rate threshold are set first. The vehicle speed threshold is generally 6-10km/h, and is used for judging whether the vehicle is in a starting vehicle condition, and when the vehicle speed is smaller than the vehicle speed threshold, the vehicle is judged to be in the starting vehicle condition; the vehicle speed threshold is determined according to the speed of the vehicle when the large throttle is started on a low-traction road surface with a jerk feeling. The wheel rotation speed change rate is the speed change amount of the vehicle in unit time, and the vehicle speed change rate threshold is generally determined according to the actual performance of the vehicle. Since the maximum acceleration is unchanged during normal running of the vehicle, the rate of change of the speed due to wheel slip is likely to be the rate of change of the speed when the actual acceleration is greater than the maximum acceleration, and the vehicle slip is determined when the rate of change of the actual speed of the vehicle is greater than the threshold value of the rate of change of the speed of the vehicle. The threshold value of the rotation speed change rate is generally determined according to the maximum change rate when the vehicle starts, and the rotation speed change rate threshold value needs to be larger than the maximum change rate when the vehicle starts, or misjudgment is easy to occur. The change rate of the wheel rotation speed is calculated according to the collected rotation speed information of the motor of the vehicle and is irrelevant to the actual displacement speed of the vehicle. The actual slip ratio of the vehicle comprises a front wheel slip ratio and a rear wheel slip ratio, the slip ratio is calculated to be accurate to the front wheel slip ratio and the rear wheel slip ratio, and the slip ratios of the front wheel and the rear wheel are calculated respectively for torque distribution. When the front wheel slip rate is greater than the slip rate threshold value, the front wheel slips; when the rear wheel slip ratio is greater than the slip ratio threshold, the rear wheel slips. The slip rate threshold is also obtained according to the actual performance of the vehicle, and belongs to a constant flexibly adjusted according to different vehicles.
In step S2, it is necessary to collect and calculate the vehicle displacement speed and the wheel rotation speed, respectively. The collection of vehicle displacement speed comes from the speed collection device of vehicle chassis, and wheel rotation speed includes front wheel speed and rear wheel speed, and wheel rotation speed can be calculated to wheel based on wheel radius and wheel transmission ratio and the motor rotational speed again, and the computational process is: front wheel speed=front wheel motor rotational speed×front wheel radius×0.377/ratio, rear wheel speed=rear wheel motor rotational speed×rear wheel radius×0.377/ratio, where ratio is the wheel transmission ratio. The front wheel speed is the average value of the front left wheel speed and the front right wheel speed, and the rear wheel speed is the average value of the rear left wheel speed and the rear right wheel speed.
Further, after the front wheel speed and the rear wheel speed are obtained, the front wheel slip rate and the rear wheel slip rate can be calculated by combining the vehicle displacement speed, wherein a smaller value in the rear wheel speed of the front wheel speed is used as a second reference vehicle speed, and the calculation process is as follows: front wheel rotation slip ratio= |second reference vehicle speed-front wheel speed|/front wheel speed; rear wheel rotation slip ratio= |second reference vehicle speed-rear wheel speed|/rear wheel speed. Meanwhile, the displacement speed of the vehicle, the front wheel speed and the rear wheel speed can be calculated to obtain the displacement slip rate of the front wheel and the displacement slip rate of the rear wheel, wherein the displacement speed of the vehicle is used as a first reference speed, and the calculation process is as follows: front wheel displacement slip ratio= |first reference vehicle speed-front wheel speed|/front wheel speed; rear wheel displacement slip ratio= |first reference vehicle speed-rear wheel speed|/rear wheel speed. Wherein the maximum value of the front wheel displacement slip rate and the front wheel rotation slip rate is taken as the front wheel slip rate, and the maximum value of the rear wheel displacement slip rate and the rear wheel rotation slip rate is taken as the rear wheel slip rate. The actual rotation speed change rate of the wheel is the amount of change in the rotation speed of the wheel per unit time.
In step S3, the calculated actual rotation speed change rate of the wheels, the slip rate of the front wheels, and the slip rate of the rear wheels are compared with the rotation speed change rate threshold and the slip rate threshold in step S1, and it is possible to determine whether the vehicle slips. When the vehicle is determined to slip, the vehicle turns on the slip-out mode while reducing the torque-up gradient. Reducing the torque up-gradient can reduce the increase in torque within the same time, and ultimately reduce the wheel end torque. The torque at the rear wheel end is forced to be the torque sent by the TCS after the intervention of the TCS (traction control system or driving anti-slip system), torque jump easily occurs in the conversion process to cause the setback, and all that is needed is to reduce the torque before the torque reducing requirement of the TCS is sent, avoid abrupt change and inhibit the setback. And then, carrying out torque distribution according to the front wheel slip rate and the rear wheel slip rate obtained by calculation in the step S2. When the front wheel slip is judged, distributing torque to the rear axle according to the actual slip rate; when the rear wheel slip is determined, torque is distributed to the front axle according to the magnitude of the actual slip ratio. The specific distribution quantity is intelligently adjusted according to the actual performances of different vehicles.
As shown in fig. 3 and 4, from top to bottom, there are graphs of changes in vehicle displacement speed, wheel speed, and torque of the vehicle. Wherein FIG. 3 shows the variation trend of various values during the normal running of the vehicle, the variation of the wheel speed is 60km/h within 0-2.5s, the variation rate of the motor speed is about 800rpm/s within 0-2.5s, and the slip ratio is less than 0.1 according to the radius of the wheels of the vehicle and the transmission ratio, so that the torque distribution is stable at 380 after about 0.3 s. Fig. 4 is a graph showing a change in the slip of the rear wheel, in which the motor rotation speed change rate at the time of the initial slip (at about 0.3 s) is about 4000 to 8000rpm/s (revolutions per second/second), and the slip rate is about 0.5 or more. The updating speed of the motor rotating speed is faster than the wheel speed, and the actual rotating speed slip rate of the vehicle is calculated according to the logic of the invention to judge the slip. According to the torque change trend, the torque has a larger mutation after TCS intervention, the slip is recognized in advance through the motor speed change rate before the torque is detected, then the torque rising process is slowed down, the sudden torque reduction caused by TCS intervention is reduced or even eliminated, and the jerk is restrained.
Further, as is clear from fig. 4, the vehicle has a skid condition at about 0.25s, if the torque distribution method of the scheme is not adopted, the torque will be greatly reduced or kept unchanged, so that the vehicle is out of control, but at the moment, the torque is slowly reduced and tends to be stable, and when the vehicle is separated from the skid condition and starts to accelerate, the initial distribution amount of the torque is restored and kept stable.
As shown in FIG. 5, the invention further provides a power torque distribution and output system for the electric four-wheel drive vehicle, which comprises an acquisition module, a processing module and a distribution module. The acquisition module acquires vehicle running data, wherein the vehicle running data comprises vehicle displacement speed and wheel rotation speed; the processing module processes the vehicle running data to obtain a front wheel slip rate and a rear wheel slip rate; the distribution module compares the front wheel slip rate and the rear wheel slip rate with a vehicle slip rate threshold value, judges whether wheel slip occurs, and distributes the torque occupation proportion of the front wheels and the rear wheels according to the sizes of the front wheel slip rate and the rear wheel slip rate.
The vehicle speed threshold value is a value in the range of 6-10km/h, and is related to the vehicle speed when the low-accessory road surface large accelerator starts to have a bump; the vehicle slip rate threshold value is determined by the performance of the vehicle, and the value of the vehicle slip rate threshold value is generally slightly larger than the maximum vehicle slip rate of the vehicle under the non-slip vehicle condition; the speed change rate threshold is also determined by the performance of the vehicle, and the value of the speed change rate threshold is generally slightly larger than the maximum speed change rate of the vehicle under the non-skid condition. All three thresholds are determined by the processing module.
The present invention also provides an electronic device including: one or more processors; and storage means for storing one or more programs which, when executed by the one or more processors, cause the electronic device to implement a method as described above.
The present invention also provides a computer-readable storage medium having stored thereon a computer program which, when executed by a processor of a computer, causes the computer to perform the above-described method.
The invention provides a torque distribution method, a system, electronic equipment and a storage medium of an electric vehicle, which are used for designing a calculation method of a slip rate and judging basic information of a vehicle condition according to the slip rate and then distributing the torque of front and rear wheels according to the slip rate.
Therefore, the electric vehicle torque distribution method can realize the identification of the slip on the low-traction road surface, obtain the slip working condition by analyzing the slip rate of the vehicle, and control the torque output and the four-wheel drive distribution on the basis so as to realize the aim of quick escape.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (15)

1. A method of torque distribution for an electric vehicle, comprising:
s1: setting a vehicle speed threshold value, a wheel rotation speed change rate threshold value and a vehicle slip rate threshold value;
s2: collecting vehicle running data, and calculating the actual rotation speed change rate of wheels and the actual slip rate of the vehicle according to the vehicle running data;
s3: comparing the calculated actual rotation speed change rate of the wheels and the calculated actual slip rate of the vehicle with the rotation speed change rate threshold of the wheels and the slip rate threshold of the vehicle respectively to determine the running vehicle condition of the vehicle;
s4: and distributing the torque occupation proportion of the front wheels and the rear wheels of the vehicle according to the running condition of the vehicle and the actual slip rate of the vehicle.
2. The electric vehicle torque distribution method according to claim 1, characterized in that in S1, the vehicle speed threshold value takes a value in a range of 6-10km/h, which is related to a vehicle speed when a low-road large throttle start has a bump; the wheel speed change rate threshold is determined according to a maximum wheel speed change rate of the vehicle in a non-slip state, and the vehicle slip rate threshold is determined according to a maximum vehicle slip rate of the vehicle in a non-slip state.
3. The electric vehicle torque distribution method according to claim 2, characterized in that in S2, the vehicle running data includes a vehicle displacement speed obtained by a velocimeter provided at the vehicle bottom and a wheel rotation speed calculated by a corresponding vehicle motor rotation speed of the vehicle and a wheel radius of the corresponding wheel.
4. The electric vehicle torque distribution method according to claim 3, characterized in that in the S2, the calculation formula of the wheel rotation speed is: wheel rotational speed = vehicle motor rotational speed x wheel radius x 0.377/ratio, where ratio is the transmission ratio of the respective motor to the respective wheel of the vehicle.
5. The electric vehicle torque distribution method according to claim 4, characterized in that in S2, a front wheel displacement slip ratio, a front wheel speed slip ratio, a rear wheel displacement slip ratio, and a rear wheel speed slip ratio are obtained from the vehicle displacement speed and the wheel rotation speed, respectively, with a maximum value of the front wheel displacement slip ratio and the front wheel speed slip ratio being a front wheel slip ratio and a maximum value of the rear wheel displacement slip ratio and the rear wheel speed slip ratio being a rear wheel slip ratio.
6. The electric vehicle torque distribution method according to claim 5, characterized in that in the S2, the wheel rotation speed includes a front wheel speed and a rear wheel speed, wherein the vehicle displacement speed is a first reference vehicle speed, a smaller value of the front wheel speed and the rear wheel speed is a second reference vehicle speed, the front wheel speed is an average of a front left wheel speed and a front right wheel speed of the vehicle, and the rear wheel speed is an average of a rear left wheel speed and a rear right wheel speed of the vehicle.
7. The electric vehicle torque distribution method according to claim 6, characterized in that the front wheel displacement slip
The vehicle speed control device comprises a front wheel rotation slip rate, a rear wheel displacement slip rate, a rear wheel rotation slip rate and a rear wheel rotation slip rate, wherein the front wheel rotation slip rate is equal to the first reference vehicle speed, the front wheel speed is equal to the second reference vehicle speed, the front wheel speed is equal to the first reference vehicle speed, the rear wheel displacement slip rate is equal to the first reference vehicle speed, the rear wheel speed is equal to the second reference vehicle speed, and the rear wheel speed is equal to the second reference vehicle speed.
8. The electric vehicle torque distribution method according to claim 6, characterized in that in the S2, the vehicle actual slip ratio includes the front wheel slip ratio and the rear wheel slip ratio, and the rotational speed change rate is obtained by calculating a change rate of the wheel rotation speed per unit time.
9. The electric vehicle torque distribution method according to claim 1, characterized in that in S3, a start vehicle condition is a start vehicle condition when a vehicle speed of the vehicle is less than the vehicle speed threshold value, a slip vehicle condition is a slip vehicle condition when the wheel actual rotation speed change rate is greater than the wheel rotation speed change rate threshold value, and a slip vehicle condition is a slip vehicle condition when the vehicle actual slip rate is greater than the vehicle slip rate threshold value.
10. The electric vehicle torque distribution method according to claim 9, characterized in that in S4, torque is distributed according to a slip condition of the vehicle front wheels and the vehicle rear wheels, and when the front wheels are the slip vehicle condition, torque is distributed to the vehicle rear axle according to the magnitude of the front wheel slip ratio; and when the rear wheels are in the skidding vehicle condition, distributing torque to the front axle of the vehicle according to the slip rate of the rear wheels.
11. An electric vehicle torque distribution system using any of claims 1-10, comprising:
the system comprises an acquisition module, a control module and a control module, wherein the acquisition module acquires vehicle running data, and the vehicle running data comprises a vehicle displacement speed and a wheel rotation speed;
the processing module is used for processing the vehicle running data to obtain a front wheel slip rate and a rear wheel slip rate;
the distribution module compares the front wheel slip rate and the rear wheel slip rate with a vehicle slip rate threshold value, judges whether wheel slip occurs, and distributes the torque occupation proportion of the front wheels and the rear wheels according to the sizes of the front wheel slip rate and the rear wheel slip rate.
12. The electric vehicle torque distribution system of claim 11, characterized in that in the processing module
The front wheel slip ratio of (a) includes a front wheel slip ratio and a front wheel speed slip ratio, the rear wheel slip ratio includes a rear wheel slip ratio and a rear wheel speed slip ratio, the maximum value of the front wheel slip ratio and the front wheel speed slip ratio is taken as the front wheel slip ratio, and the maximum value of the rear wheel slip ratio and the rear wheel speed slip ratio is taken as the rear wheel slip ratio.
13. The electric vehicle torque distribution system of claim 12, wherein the vehicle slip rate threshold in the distribution module is determined from historical data collected by the acquisition module.
14. An electronic device, comprising:
one or more processors;
storage means for storing one or more programs which when executed by the one or more processors cause the electronic device to implement the method of any of claims 1-10.
15. A computer readable storage medium, having stored thereon a computer program which, when executed by a processor of a computer, causes the computer to perform the method of any of claims 1-10.
CN202310346082.4A 2023-04-03 2023-04-03 Electric vehicle torque distribution method, system, electronic equipment and storage medium Pending CN116278806A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310346082.4A CN116278806A (en) 2023-04-03 2023-04-03 Electric vehicle torque distribution method, system, electronic equipment and storage medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310346082.4A CN116278806A (en) 2023-04-03 2023-04-03 Electric vehicle torque distribution method, system, electronic equipment and storage medium

Publications (1)

Publication Number Publication Date
CN116278806A true CN116278806A (en) 2023-06-23

Family

ID=86828763

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310346082.4A Pending CN116278806A (en) 2023-04-03 2023-04-03 Electric vehicle torque distribution method, system, electronic equipment and storage medium

Country Status (1)

Country Link
CN (1) CN116278806A (en)

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