Vehicle driving anti-slip control method and system and vehicle

Abstract

The invention is suitable for the technical field of vehicle control, and particularly relates to a vehicle driving anti-slip control method and system and a vehicle. The method comprises the following steps: determining front and rear axle rotating speeds and front and rear axle speed difference according to the wheel speeds of four wheels obtained by calculating the vehicle speed and the rotating angle, correcting the front and rear axle rotating speeds to obtain corrected front and rear axle rotating speeds, and determining the front and rear axle rotating speed difference according to the collected actual wheel speeds of the four wheels and the front and rear axle speed difference. Acquiring the current rotating speeds of the front and rear motors in real time, controlling the current rotating speeds of the front and rear motors not to exceed the corresponding rotating speed limits of the front and rear motors, acquiring the rotating speed limits of the motors by using the calculated wheel speeds, and identifying the slip condition according to the rotating speed limits. The method has high precision and real-time performance, so that the control period of the motor can be shortened, and the precision of anti-slip control is improved.

Description

Technical Field

[0001] This application is applicable to the field of vehicle control technology, and particularly relates to a vehicle drive anti-slip control method, system and vehicle. Background Art

[0002] With the increasingly obvious trend of electrification of automotive drive systems, there are more and more models with multiple motors driving the front and rear axles. Reasonably distributing the torque of multiple power sources has become an important issue according to different dimensions.

[0003] Currently, the control of the longitudinal slip ratio of a vehicle mainly relies on the Electronic Stability Program (ESP) to control. The reference vehicle speed is estimated through a vehicle model, and it is determined whether the vehicle is slipping by judging the vehicle speed of four wheels. Then, the Traction Control System (TCS) function is activated, so that the vehicle's power system reduces the torque of a certain drive motor or the braking system requests hydraulic braking to inhibit the increase of the wheel speed. The Vehicle Control Unit (VCU) then calculates the torque to be transferred and determines the transfer according to the torque reduction request of the ESP and its original request for this power source, so as to realize the transfer of the drive torque between multiple motors.

[0004] However, judging whether the vehicle is slipping according to the wheel speed sensor has a low accuracy and real-time performance of the wheel speed sensor. Moreover, after the ESP determines the slip and requests the power system to reduce the torque and transfer the torque, there will be a large delay, which ultimately has a certain impact on the control accuracy.

[0005] Therefore, how to improve the identification of wheel slip to improve the accuracy of anti-slip control has become an urgent problem to be solved. Summary of the Invention

[0006] In view of this, the embodiments of this application provide a vehicle drive anti-slip control method, system and vehicle to solve the problem of how to improve the identification of wheel slip to improve the accuracy of anti-slip control.

[0007] In a first aspect, the embodiments of this application provide a vehicle drive anti-slip control method, including: Determine the left front wheel speed, right front wheel speed, left rear wheel speed and right rear wheel speed according to the collected current vehicle speed, left front wheel angle and right front wheel angle, in combination with the first set of fixed vehicle parameters; Determine the front axle speed, rear axle speed, front axle speed difference and rear axle speed difference according to the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed, and correct the front axle speed and the rear axle speed to obtain the corrected front axle speed and the corrected rear axle speed; Determine the front axle rotational speed difference and the rear axle rotational speed difference based on the actual wheel speeds of the four wheels collected, the front axle speed difference, and the rear axle speed difference. Based on the corrected front axle rotational speed, the corrected rear axle rotational speed, the front axle rotational speed difference, and the rear axle rotational speed difference, and in combination with the second set of fixed vehicle parameters, obtain the front motor speed limit and the rear motor speed limit; Collect the current rotational speeds of the front motor and the rear motor in real time, and control the current rotational speed of the front motor not to exceed the front motor speed limit and the current rotational speed of the rear motor not to exceed the rear motor speed limit.

[0008] In a second aspect, an embodiment of the present application provides a vehicle drive anti-slip control system, including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the vehicle drive anti-slip control method described in the first aspect above.

[0009] In a third aspect, an embodiment of the present application provides a vehicle, including the vehicle drive anti-slip control system described in the second aspect above.

[0010] The beneficial effects of the embodiments of the present application compared with the prior art are as follows: The present application determines the left front wheel speed, the right front wheel speed, the left rear wheel speed, and the right rear wheel speed based on the currently collected vehicle speed, the left front wheel angle, and the right front wheel angle, and in combination with the first set of fixed vehicle parameters. Based on the left front wheel speed, the right front wheel speed, the left rear wheel speed, and the right rear wheel speed, determine the front axle rotational speed, the rear axle rotational speed, the front axle speed difference, and the rear axle speed difference, correct the front axle rotational speed and the rear axle rotational speed to obtain the corrected front axle rotational speed and the corrected rear axle rotational speed. Determine the front axle rotational speed difference and the rear axle rotational speed difference based on the actual wheel speeds of the four wheels collected, the front axle speed difference, and the rear axle speed difference. Based on the corrected front axle rotational speed, the corrected rear axle rotational speed, the front axle rotational speed difference, and the rear axle rotational speed difference, and in combination with the second set of fixed vehicle parameters, obtain the front motor speed limit and the rear motor speed limit. Collect the current rotational speeds of the front motor and the rear motor in real time, and control the current rotational speed of the front motor not to exceed the front motor speed limit and the current rotational speed of the rear motor not to exceed the rear motor speed limit. Use the calculated wheel speeds to obtain the motor speed limit and identify slip conditions based on this limit, with high accuracy and real-time performance, thereby shortening the control cycle of the motor and improving the accuracy of anti-slip control. Description of the Drawings

[0011] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0012] Figure 1 It is a schematic structural diagram of a four-wheel drive vehicle control system provided in Embodiment 1 of the present application; Figure 2 It is a schematic flow diagram of a vehicle driving anti-slip control method provided in Embodiment 2 of the present application; Figure 3 It is a schematic principle diagram of Ackermann steering calculation provided in Embodiment 2 of the present application; Figure 4 It is a schematic flow diagram of a torque distribution calculation provided in Embodiment 3 of the present application; Figure 5 It is a schematic structural diagram of a torque distribution calculation provided in Embodiment 4 of the present application; Figure 6 It is a schematic structural diagram of a vehicle information interaction provided in Embodiment 5 of the present application; Figure 7 It is a schematic structural diagram of a vehicle driving anti-slip control system provided in Embodiment 6 of the present application. Detailed implementation manners

[0013] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are presented to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, the detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0014] It should be understood that when used in the specification of the present application and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0015] In addition, in the description of the specification of the present application and the appended claims, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0016] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that specific features, structures or characteristics described in connection with that embodiment are included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments" etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized.

[0017] It should be understood that the magnitudes of the sequence numbers of the steps in the following embodiments do not mean the order of execution is prior or posterior. The order of execution of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this application.

[0018] To illustrate the technical solution of this application, the following specific embodiments are used for illustration.

[0019] See Figure 1 , which is a schematic structural diagram of a four-wheel drive vehicle control system provided by Embodiment 1 of this application. The four-wheel drive vehicle control system includes a vehicle controller, a front motor, a front motor controller, a rear motor, and a rear motor controller. Among them, the front motor drives the left front wheel and the right front wheel through the front axle, and the rear motor drives the left rear wheel and the right rear wheel through the rear axle.

[0020] The vehicle controller coordinates and controls together with controllers such as the front motor controller and the rear motor controller to implement the vehicle drive anti-slip control method of this application.

[0021] The vehicle controller calculates and outputs the maximum speed limit of the drive motor according to signals such as the current four-wheel speeds and sends it to the front / rear motor controller. According to the motor speed and the actual motor torque fed back by the front / rear motor controller, the torque transfer amounts of the front and rear axles are calculated and sent to the front / rear motor controller respectively to realize the torque transfer between the front and rear axles. The vehicle controller, as the coordination center of the entire control strategy, coordinates the work of each controller to ensure the orderly execution of the entire control strategy from the entire system.

[0022] The front / rear motor controller uses the target shaft speed and the motor speed, and combines the torque limit issued by the vehicle controller to perform PID adjustment to actually execute the torque reduction control. The front / rear motor controller, as the actuator in the entire control strategy, actually executes the torque and speed limits of the anti-slip control.

[0023] See Figure 2 , which is a schematic flowchart of a vehicle drive anti-slip control method provided by Embodiment 2 of this application, as Figure 2As shown, the vehicle driving anti-slip control method includes the following steps: Step S201: Determine the left front wheel speed, right front wheel speed, left rear wheel speed, and right rear wheel speed according to the collected current vehicle speed, left front wheel angle, and right front wheel angle, in combination with the first set of fixed vehicle parameters.

[0024] In this embodiment, the current vehicle speed represents the vehicle speed information collected by the vehicle speed sensor at the current calculation moment. The left front wheel angle represents the angle information collected by the angle sensor installed at the left front wheel of the vehicle at the current calculation moment. The right front wheel angle represents the angle information collected by the angle sensor installed at the right front wheel of the vehicle at the current calculation moment. Of course, the steering angle of the steering wheel can also be used for conversion to obtain the steering angles of the front and rear wheels. Among them, there may be a situation where the angles of the left front wheel and the right front wheel are inconsistent during steering.

[0025] The above vehicle speed can be the centroid reference vehicle speed. Of course, under certain error conditions, it can also be the vehicle speed represented by other positions.

[0026] Optionally, the current vehicle speed is the centroid reference vehicle speed, and the first set of fixed vehicle parameters includes the vehicle wheelbase, vehicle track width, distance from the centroid to the front axle, and distance from the centroid to the rear axle; Determining the left front wheel speed, right front wheel speed, left rear wheel speed, and right rear wheel speed according to the collected current vehicle speed, left front wheel angle, and right front wheel angle, in combination with the first set of fixed vehicle parameters, includes: Determine the steering direction according to the collected left front wheel angle and right front wheel angle, and determine the wheel speed calculation model according to the steering direction and the Ackermann steering principle; Input the collected current vehicle speed, left front wheel angle, right front wheel angle, and the first set of fixed vehicle parameters into the wheel speed calculation model, and output the left front wheel speed, right front wheel speed, left rear wheel speed, and right rear wheel speed.

[0027] Among them, the four-wheel speeds can be calculated according to the Ackermann steering principle. For example, Figure 3 As shown, it is a schematic diagram of the principle of Ackermann steering calculation provided by the second embodiment of the present application. Among them, the input of the Ackermann steering calculation is the centroid reference vehicle speed V0. According to the corresponding relationship between the steering wheel angle and the front wheel angle (a fixed relationship designed for the same vehicle model), the left front wheel angle θ and the right front wheel angle ω can be obtained. The fixed parameters include the vehicle wheelbase L, vehicle track width B, distance b from the centroid to the rear axle, and distance a from the centroid to the front axle. The output of the Ackermann steering calculation is the left front wheel speed V1, right front wheel speed V2, left rear wheel speed V3, and right rear wheel speed V4.

[0028] If the vehicle is turning left, the following formula is used for calculation: If the vehicle is turning right, the following formula is used for calculation: .

[0029] The calculation of the rotational speed is performed using the Ackermann steering principle, rather than determining whether the vehicle is slipping based on the wheel speed sensors. Compared with the low accuracy and low real-time performance of the wheel speed sensors, the above calculation method can obtain the rotational speed with high precision and in real time.

[0030] Step S202: Determine the front axle rotational speed, rear axle rotational speed, front axle speed difference, and rear axle speed difference based on the left front wheel speed, right front wheel speed, left rear wheel speed, and right rear wheel speed, and correct the front axle rotational speed and rear axle rotational speed to obtain the corrected front axle rotational speed and corrected rear axle rotational speed.

[0031] In this embodiment, the front axle rotational speed and front axle speed difference are determined by the left front wheel speed and right front wheel speed, and the rear axle rotational speed and rear axle speed difference are determined by the left rear wheel speed and right rear wheel speed.

[0032] The front axle rotational speed and rear axle rotational speed correspond to a certain allowable slip error range. Therefore, the front axle rotational speed and rear axle rotational speed can be corrected to obtain the corrected front axle rotational speed and corrected rear axle rotational speed within a certain range.

[0033] Optionally, determining the front axle rotational speed, rear axle rotational speed, front axle speed difference, and rear axle speed difference based on the left front wheel speed, right front wheel speed, left rear wheel speed, and right rear wheel speed includes: Taking the average of the left front wheel speed and the right front wheel speed, and determining the obtained average value as the front axle rotational speed; taking the average of the left rear wheel speed and the right rear wheel speed, and determining the obtained average value as the rear axle rotational speed; Taking the difference between the left front wheel speed and the right front wheel speed, and determining the obtained difference as the front axle speed difference; taking the difference between the left rear wheel speed and the right rear wheel speed, and determining the obtained difference as the rear axle speed difference.

[0034] Among them, the front / rear axle rotational speed and front / rear axle speed difference are calculated according to the following formula: 、 、 、 , In the formula, represents the front axle rotational speed, represents the rear axle rotational speed, Characterize the front axle speed difference, Characterize the rear axle speed difference.

[0035] Expressing the front axle rotational speed, rear axle rotational speed, front axle speed difference, and rear axle speed difference in the above manner can obtain accurate rotational speed and speed difference calculation results for subsequent calculations, improving the control accuracy.

[0036] Optionally, correct the front axle rotational speed and rear axle rotational speed to obtain the corrected front axle rotational speed and corrected rear axle rotational speed, including: Divide the front axle rotational speed by the rear axle rotational speed to obtain the front-to-rear axle rotational speed ratio, and look up the preset slip speed based on the front-to-rear axle rotational speed ratio to obtain the correction offset; Add the correction offset to the front axle rotational speed to determine the sum as the corrected front axle rotational speed, and add the correction offset to the rear axle rotational speed to determine the sum as the corrected rear axle rotational speed.

[0037] Among them, the correction offset Is the allowable slip speed difference during slip control, and is obtained by looking up the slip speed table based on the front axle rotational speed and rear axle rotational speed respectively (specifically ), for example, the slip speed table is Table 1 below: Table 1 The calculation formula for the correction calculation is as follows: 、 , In the formula, Characterize the corrected front axle rotational speed, Characterize the corrected rear axle rotational speed.

[0038] Using the preset slip speed table can configure corresponding errors for slip to control slip within the allowable range and improve the robustness of control. The preset slip speed table can be obtained through experiments or calibration, and specifically, different tables can be configured for each vehicle model to improve vehicle targeting.

[0039] Step S203, determine the front axle rotational speed difference and rear axle rotational speed difference based on the actual wheel speeds, front axle speed difference, and rear axle speed difference of the four wheels collected, and obtain the front motor speed limit and rear motor speed limit based on the corrected front axle rotational speed, corrected rear axle rotational speed, front axle rotational speed difference, and rear axle rotational speed difference, combined with the second actual vehicle fixed parameters.

[0040] In this embodiment, by combining the actual wheel speeds of the four wheels and the front / rear axle speed differences determined in step S202, the current front / rear axle rotational speed differences can be determined, which are then used for subsequent calculations of the front / rear motor speed limits. The front / rear motor speed limits are related to the front / rear axle rotational speeds and front / rear axle speed differences.

[0041] Optionally, based on the actual wheel speeds, front axle speed difference, and rear axle speed difference of the four collected rounds, determine the front axle rotational speed difference and the rear axle rotational speed difference, including: Subtract the actual wheel speed of the left front wheel from the actual wheel speed of the right front wheel to obtain a first subtraction result. Subtract the first subtraction result from the front axle speed difference to obtain a second subtraction result. Determine that half of the absolute value of the second subtraction result is the front axle rotational speed difference; Subtract the actual wheel speed of the left rear wheel from the actual wheel speed of the right rear wheel to obtain a third subtraction result. Subtract the third subtraction result from the rear axle speed difference to obtain a fourth subtraction result. Determine that half of the absolute value of the fourth subtraction result is the rear axle rotational speed difference.

[0042] Among them, the calculation formula for the front / rear axle rotational speed difference is as follows: 、 , In the formula, represents the front axle rotational speed difference, represents the rear axle rotational speed difference, represents the actual wheel speed of the left front wheel, represents the actual wheel speed of the right front wheel, represents the actual wheel speed of the left rear wheel, represents the actual wheel speed of the right rear wheel.

[0043] The above calculation combines the actual wheel speed and the theoretical speed difference to obtain the actual rotational speed difference, which can effectively reflect the rotational speed difference of the front and rear axle motors, thus providing accurate prerequisite parameter conditions for subsequent rotational speed limitation.

[0044] Optionally, the second set of real vehicle fixed parameters includes the first speed ratio from the front motor to the wheel end, the second speed ratio from the rear motor to the wheel end, and the wheel tire radius; Based on the corrected front axle rotational speed, corrected rear axle rotational speed, front axle rotational speed difference, and rear axle rotational speed difference, combined with the second set of real vehicle fixed parameters, obtain the front motor rotational speed limitation and the rear motor rotational speed limitation, including: Based on the corrected front axle rotational speed, front axle rotational speed difference, first speed ratio, and wheel tire radius, obtain the front motor rotational speed limitation. Among them, the sum of the corrected front axle rotational speed and the front axle rotational speed difference, and the first speed ratio are all positively correlated with the front motor rotational speed limitation, and the wheel tire radius is inversely correlated with the front motor rotational speed limitation; Based on the corrected rear axle rotational speed, rear axle rotational speed difference, second speed ratio, and wheel tire radius, obtain the rear motor rotational speed limitation. Among them, the sum of the corrected rear axle rotational speed and the rear axle rotational speed difference, and the second speed ratio are all positively correlated with the rear motor rotational speed limitation, and the wheel tire radius is inversely correlated with the rear motor rotational speed limitation.

[0045] Among them, the calculation formula for the front / rear motor rotational speed limitation is as follows: , In the formula, is the front motor speed limit, is the rear motor speed limit, r1 is the speed ratio from the front motor to the wheel end, r2 is the speed ratio from the front motor to the wheel end, and R is the radius of the vehicle tire.

[0046] The above calculation can accurately reflect the speed limits of the front motor and the rear motor, so that it can be determined whether the vehicle slips in subsequent judgments. That is, when the speed limit is exceeded, it can be considered that there is a slipping situation, and when the speed limit is not exceeded, it can be considered that there is no slipping.

[0047] Step S204: Real-time collect the current speed of the front motor and the current speed of the rear motor, and control the current speed of the front motor not to exceed the front motor speed limit and the current speed of the rear motor not to exceed the rear motor speed limit.

[0048] In this embodiment, the motor controller can collect the current speed of the corresponding motor in real time and compare the speed with the above speed limit. Among them, for the front motor, the current speed of the front motor is compared with the front motor speed limit, and for the rear motor, the current speed of the rear motor is compared with the rear motor speed limit.

[0049] When the corresponding speed limit is exceeded, it is necessary to adjust the output torque of the motor so that the speed of the corresponding motor does not exceed the corresponding speed limit to prevent slipping.

[0050] In the embodiment of the present application, according to the collected current vehicle speed, left front wheel angle and right front wheel angle, combined with the first set of fixed vehicle parameters, the left front wheel speed, right front wheel speed, left rear wheel speed and right rear wheel speed are determined. According to the left front wheel speed, right front wheel speed, left rear wheel speed and right rear wheel speed, the front axle speed, rear axle speed, front axle speed difference and rear axle speed difference are determined, and the front axle speed and rear axle speed are corrected to obtain the corrected front axle speed and corrected rear axle speed. According to the actual wheel speeds of the four wheels, front axle speed difference and rear axle speed difference collected, the front axle speed difference and rear axle speed difference are determined. According to the corrected front axle speed, corrected rear axle speed, front axle speed difference and rear axle speed difference, combined with the second set of fixed vehicle parameters, the front motor speed limit and rear motor speed limit are obtained. Real-time collect the current speed of the front motor and the current speed of the rear motor, control the current speed of the front motor not to exceed the front motor speed limit and the current speed of the rear motor not to exceed the rear motor speed limit, use the calculated wheel speeds to obtain the motor speed limit, and identify the slipping situation based on this limit, which has high accuracy and real-time performance, so that the control cycle of the motor can be shortened and the anti-slip control accuracy can be improved.

[0051] See Figure 4, which is a schematic flowchart of torque distribution calculation provided in the third embodiment of the present application. Among them, it solves the process of how to control the motor not to exceed the corresponding speed limit.

[0052] Among them, for controlling the current speed of the front motor in step S204 not to exceed the front motor speed limit, it includes: Sum the collected front axle driver demand torque and the rear axle torque transfer amount at the previous moment to obtain the front axle demand torque; If it is detected that the current speed of the front motor exceeds the front motor speed limit, generate a front axle torque reduction request torque, determine the smaller value between the front axle torque reduction request torque and the front axle demand torque as the front motor request torque, and control the front motor to output the front motor request torque; Subtract the front motor request torque from the front axle driver demand torque, determine the obtained difference as the front axle torque transfer amount, and transfer the front axle torque transfer amount to the rear motor; If it is detected that the current speed of the front motor does not exceed the front motor speed limit, control the front motor to output the front axle demand torque.

[0053] In addition, for controlling the current speed of the rear motor in step S204 not to exceed the rear motor speed limit, it includes: Sum the collected rear axle driver demand torque and the rear axle torque transfer amount to obtain the rear axle demand torque; If it is detected that the current speed of the rear motor exceeds the rear motor speed limit, generate a rear axle torque reduction request torque, determine the smaller value between the rear axle torque reduction request torque and the rear axle demand torque as the rear motor request torque, and control the rear motor to output the rear motor request torque; Subtract the rear motor request torque from the rear axle driver demand torque, determine the obtained difference as the rear axle torque transfer amount, and transfer the rear axle torque transfer amount to the front motor; If it is detected that the current speed of the rear motor does not exceed the rear motor speed limit, control the rear motor to output the rear axle demand torque.

[0054] Among them, for the front motor, if the actual speed of the front motor exceeds the front motor speed limit, it is determined that the front axle torque reduction is activated. For the rear motor, if the actual speed of the rear motor exceeds the rear motor speed limit, it is determined that the rear axle torque reduction is activated.

[0055] For the front axle, the front axle torque reduction request torque is tq_dec_fr = tq_FrMot_act * r1 + offset1, where tq_FrMot_act is the actual torque of the motor feedback by the front motor controller; r1 is the speed ratio from the front motor to the wheel end; offset1 is a calibrated value obtained through vehicle calibration and matching. For example, offset1 is 100 Nm.

[0056] For the rear axle, the torque reduction request torque of the rear axle is tq_dec_re = tq_ReMot_act * r2 + offset2, where tq_ReMot_act is the actual torque of the motor feedback by the front motor controller; R2 is the speed ratio from the rear motor to the wheel end; offset2 is a calibrated value obtained through vehicle calibration and matching. For example, offset2 is 100 Nm.

[0057] For the front motor, the requested torque is tq_MotReq_fr, which is calculated as follows: If the front axle torque reduction is not activated, then tq_MotReq_fr = tq_DrvReq_fr + tq_tsf_re_old; if the front axle torque reduction is activated, then tq_MotReq_fr = min(tq_dec_fr, tq_FrMot_act, (tq_DrvReq_fr + tq_tsf_re_old)); the front axle torque transfer amount tq_tsf_fr = tq_DrvReq_fr - tq_MotReq_fr; where tq_DrvReq_fr is the driver demand torque of the front axle, and tq_tsf_re_old is the rear axle torque transfer amount calculated in the previous operation cycle. For the rear motor, the requested torque is tq_MotReq_re, which is calculated as follows: If the front and rear axle torque reduction is not activated, then tq_MotReq_re = tq_DrvReq_fr + tq_tsf_fr; if the front and rear axle torque reduction is activated, then tq_MotReq_re = min(tq_dec_re, tq_ReMot_act, (tq_DrvReq_re + tq_tsf_fr)); the rear axle torque transfer amount tq_tsf_re_old = tq_DrvReq_re - tq_MotReq_re; where tq_DrvReq_re is the driver demand torque of the rear axle, and tq_tsf_fr is the front axle torque transfer amount calculated in the current operation cycle.

[0058] Correspondingly, as Figure 5 shown, it is a schematic flow chart of torque distribution calculation provided by the fourth embodiment of the present application, where the front axle torque reduction and the rear axle torque reduction are not activated, that is, the current speeds of the front / rear motors do not exceed the corresponding speed limits.

[0059] As Figure 6As shown in the figure, it is a schematic structural diagram of a vehicle information interaction provided in the fifth embodiment of the present application. Specifically, it is defined that the vehicle controller is used to implement limit calculation and torque distribution, while the front / rear motor controllers are used to implement the judgment of whether to reduce torque and the torque calculation after torque reduction. Different algorithms are respectively embedded in the vehicle controller and the front / rear motor controllers to shorten the control cycle, and prevent the unstable risk during vehicle acceleration caused by the large dynamics of the drive wheels in the fastest way. The target torque and transfer torque for torque reduction can be calculated based on the speed control results of the front / rear motor controllers, with accurate torque and high real-time performance.

[0060] As Figure 7 shown in the figure, it is a schematic structural diagram of a vehicle drive anti-slip control system provided in the sixth embodiment of the present application. The central control device belongs to the vehicle drive anti-slip control system. Among them, it includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the vehicle drive anti-slip control method recorded in the above embodiments. Among them, when there is more than one processor, it can respectively correspond to the vehicle controller, the front motor controller, the rear motor controller, etc.

[0061] In addition, the embodiment of the present application also provides a vehicle, which includes the vehicle drive anti-slip control system in the above embodiment.

[0062] Those skilled in the art can understand that Figure 7 merely an example of the vehicle drive anti-slip control system, and does not constitute a limitation on the computer device. The computer device may include more or fewer components than shown in the figure, or combine some components, or different components.

[0063] The so-called processor may be a CPU, and this processor may also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application-specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf programmable gate arrays (Field-Programmable Gate Array, FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or this processor may also be any conventional processor, etc.

[0064] The memory includes a readable storage medium, an internal memory, etc. Among them, the internal memory can be the memory of a computer device, and the internal memory provides an environment for the operation of the operating system and computer-readable instructions in the readable storage medium. The readable storage medium can be the hard disk of a computer device, and in some other embodiments, it can also be an external storage device of a computer device. For example, a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. equipped on the computer device. Further, the memory can also include both the internal storage unit of the computer device and the external storage device. The memory is used to store an operating system, application programs, a Boot Loader, data, and other programs, such as the program code of a computer program. The memory can also be used to temporarily store data that has been output or will be output.

[0065] In the above embodiments, the descriptions of each embodiment have their own emphases. For parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0066] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0067] In the embodiments provided in this application, it should be understood that the disclosed device / control device and method can be implemented in other ways. For example, the device / control device embodiments described above are only illustrative. For example, the division of modules or units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be in an electrical, mechanical or other form.

[0068] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0069] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A vehicle driving anti-skid control method, characterized in that: include: According to the collected current vehicle speed, left front wheel steering angle and right front wheel steering angle, combined with the first real vehicle fixed parameters, determine the left front wheel speed, right front wheel speed, left rear wheel speed and right rear wheel speed; Determine the front axle speed, the rear axle speed, the front axle speed difference and the rear axle speed difference according to the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed, and correct the front axle speed and the rear axle speed to obtain a corrected front axle speed and a corrected rear axle speed; Determine the front axle speed difference and the rear axle speed difference according to the collected actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference, and obtain the front motor speed limit and the rear motor speed limit according to the corrected front axle speed, the corrected rear axle speed, the front axle speed difference and the rear axle speed difference in combination with the second real vehicle fixed parameters; The current rotation speed of the front motor and the current rotation speed of the rear motor are collected in real time, and the current rotation speed of the front motor is controlled not to exceed the front motor rotation speed limit and the current rotation speed of the rear motor is controlled not to exceed the rear motor rotation speed limit.

2. The vehicle driving anti-skid control method according to claim 1, characterized in that: The current vehicle speed is a reference vehicle speed of the center of mass, and the first real vehicle fixed parameters include the vehicle wheelbase, the vehicle track, the distance between the center of mass and the front axle, and the distance between the center of mass and the rear axle; The method of determining the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed based on the collected current vehicle speed, the left front wheel angle and the right front wheel angle in combination with the first real vehicle fixed parameter includes: Determine the steering direction according to the collected left front wheel angle and right front wheel angle, and determine the wheel speed calculation model according to the steering direction and the Ackerman steering principle; The collected current vehicle speed, the left front wheel steering angle, the right front wheel steering angle and the first real vehicle fixed parameter are input into the wheel speed calculation model, and the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed are output.

3. The vehicle driving anti-skid control method according to claim 1, characterized in that: Determining the front axle speed, the rear axle speed, the front axle speed difference and the rear axle speed difference according to the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed comprises: The left front wheel speed and the right front wheel speed are averaged to determine the average value as the front axle speed, and the left rear wheel speed and the right rear wheel speed are averaged to determine the average value as the rear axle speed; The left front wheel speed and the right front wheel speed are subtracted to determine the difference as the front axle speed difference, and the left rear wheel speed and the right rear wheel speed are subtracted to determine the difference as the rear axle speed difference.

4. The vehicle driving anti-skid control method according to claim 1, characterized in that: The step of correcting the front axle speed and the rear axle speed to obtain a corrected front axle speed and a corrected rear axle speed includes: Comparing the front axle speed with the rear axle speed to obtain a front-rear axle speed ratio, and looking up a preset slip speed table according to the front-rear axle speed ratio to obtain a correction bias; The correction offset is added to the front axle speed, and the sum is determined to be the corrected front axle speed. The correction offset is added to the rear axle speed, and the sum is determined to be the corrected rear axle speed.

5. The vehicle driving anti-skid control method according to claim 1, characterized in that: The determining the front axle speed difference and the rear axle speed difference according to the collected actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference comprises: Subtracting the collected actual wheel speed of the left front wheel from the actual wheel speed of the right front wheel to obtain a first subtraction result, subtracting the first subtraction result from the front axle speed difference to obtain a second subtraction result, and determining half of the absolute value of the second subtraction result as the front axle speed difference; Subtract the collected actual wheel speed of the left rear wheel and the actual wheel speed of the right rear wheel to obtain a third subtraction result, subtract the third subtraction result from the rear axle speed difference to obtain a fourth subtraction result, and determine half of the absolute value of the fourth subtraction result as the rear axle speed difference.

6. The vehicle driving anti-skid control method according to claim 1, characterized in that: The second real vehicle fixed parameters include a first speed ratio from the front motor to the wheel end, a second speed ratio from the rear motor to the wheel end, and a wheel tire radius; The method of obtaining the front motor speed limit and the rear motor speed limit according to the corrected front axle speed, the corrected rear axle speed, the front axle speed difference and the rear axle speed difference in combination with the second real vehicle fixed parameter includes: Obtaining a front motor speed limit according to the corrected front axle speed, the front axle speed difference, the first speed ratio and the wheel tire radius, wherein the sum of the corrected front axle speed and the front axle speed difference and the first speed ratio are both positively correlated with the front motor speed limit, and the wheel tire radius is negatively correlated with the front motor speed limit; The rear motor speed limit is obtained based on the corrected rear axle speed, the rear axle speed difference, the second speed ratio and the wheel tire radius, wherein the sum of the corrected rear axle speed and the rear axle speed difference and the second speed ratio are positively correlated with the rear motor speed limit, and the wheel tire radius is negatively correlated with the rear motor speed limit.

7. The vehicle driving anti-skid control method according to claim 1, characterized in that: The controlling the current speed of the front motor to not exceed the speed limit of the front motor includes: The collected front axle driver demand torque and the rear axle torque transfer at the previous moment are summed to obtain the front axle demand torque; If it is detected that the current speed of the front motor exceeds the front motor speed limit, a front axle torque reduction request torque is generated, a smaller value between the front axle torque reduction request torque and the front axle required torque is determined as the front motor request torque, and the front motor is controlled to output the front motor request torque; Divide the front axle driver demand torque and the front motor request torque to obtain a difference, determine the difference as a front axle torque transfer amount, and transfer the front axle torque transfer amount to the rear motor; If it is detected that the current rotation speed of the front motor does not exceed the front motor rotation speed limit, the front motor is controlled to output the required torque of the front axle.

8. The vehicle driving anti-skid control method according to claim 7, characterized in that: The controlling the current speed of the rear motor to not exceed the speed limit of the rear motor includes: The collected rear axle driver demand torque and the rear axle torque transfer amount are summed to obtain the rear axle demand torque; If it is detected that the current speed of the rear motor exceeds the speed limit of the rear motor, a rear axle torque reduction request torque is generated, a smaller value between the rear axle torque reduction request torque and the rear axle required torque is determined as the rear motor request torque, and the rear motor is controlled to output the rear motor request torque; Subtracting the rear axle driver demand torque from the rear motor request torque to determine the difference as a rear axle torque transfer amount, and transferring the rear axle torque transfer amount to the front motor; If it is detected that the current rotation speed of the rear motor does not exceed the rear motor rotation speed limit, the rear motor is controlled to output the rear axle required torque.

9. A vehicle driving anti-skid control system, characterized in that: The method comprises a processor, a memory and a computer program stored in the memory and executable on the processor, wherein the processor implements the vehicle driving anti-skid control method as claimed in any one of claims 1 to 8 when executing the computer program.

10. A vehicle, characterized in that: It comprises the vehicle drive anti-skid control system as claimed in claim 9.

Images