Vehicle drive anti-slip control method, system and vehicle

Abstract

The application is suitable for the field of vehicle control technology, and particularly relates to a vehicle driving anti-slip control method, system and vehicle. The method determines front and rear axle speeds and front and rear axle speed differences according to wheel speeds of four wheels calculated based on vehicle speed and steering angle, corrects the front and rear axle speeds to obtain corrected front and rear axle speeds, determines front and rear axle speed differences according to actual wheel speeds of the four wheels and the front and rear axle speed differences, obtains front and rear motor speed limits according to the corrected front and rear axle speeds and the front and rear axle speed differences, collects current front and rear motor speeds in real time, controls the current front and rear motor speeds to be less than the corresponding front and rear motor speed limits, uses the calculated wheel speeds to obtain the motor speed limits, and uses the motor speed limits to identify the slipping condition, has high precision and real-time performance, so that the control cycle of the motor can be shortened, and the precision of the anti-slip control is improved.

Description

TECHNICAL FIELD

[0001] The present application is suitable for the technical field of vehicle control, and in particular relates to a vehicle driving anti-slip control method and system and a vehicle. BACKGROUND

[0002] With the increasing trend of electric drive of automobile drive systems, more and more vehicle models are driven by multiple motors on the front and rear axles. According to different and dimensional, it is an important issue to reasonably distribute the torque of multiple power sources.

[0003] At present, the control of the longitudinal slip rate of the vehicle mainly relies on the Electronic Stability Program (ESP) to control the reference vehicle speed estimated by the vehicle model and the wheel speed of the four wheels to determine whether the vehicle is slipping, and then activate the Traction Control System (TCS) function to make the vehicle power system reduce the torque of a certain drive motor or request hydraulic braking of the braking system to suppress the rise of the wheel speed. The Vehicle Control Unit (VCU) calculates the torque to be transferred and determines the transfer according to the torque reduction request of the ESP and the original request of the power source itself, and realizes the transfer of the driving torque between multiple motors.

[0004] However, according to the wheel speed sensor to determine whether the vehicle is slipping, since the wheel speed sensor has low accuracy and low real-time performance, and since the ESP determines that the vehicle is slipping, the power system is requested to reduce the torque and transfer the torque, which will have a large delay, and finally has a certain influence on the control accuracy.

[0005] Therefore, how to improve the wheel slip identification to improve the accuracy of the anti-slip control has become a problem to be solved. SUMMARY

[0006] Therefore, the present application provides a vehicle driving anti-slip control method and system to solve the problem of how to improve the wheel slip identification to improve the accuracy of the anti-slip control.

[0007] In a first aspect, the present application provides a vehicle driving anti-slip control method, comprising:

[0008] According to the collected current vehicle speed, left front wheel steering angle and right front wheel steering angle, the left front wheel speed, right front wheel speed, left rear wheel speed and right rear wheel speed are determined in combination with the first real vehicle fixed parameters;

[0009] determine a front axle speed difference and a rear axle speed difference according to the actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference, and obtain a front motor speed limit and a rear motor speed limit according to the modified front axle speed, the modified rear axle speed, the front axle speed difference and the rear axle speed difference, in combination with the second real vehicle fixed parameter;

[0010] determine a front axle speed difference and a rear axle speed difference according to the actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference, and obtain a front motor speed limit and a rear motor speed limit according to the modified front axle speed, the modified rear axle speed, the front axle speed difference and the rear axle speed difference, in combination with the second real vehicle fixed parameter;

[0011] real-time collect a current front motor speed and a current rear motor speed, and control the current front motor speed not to exceed the front motor speed limit and the current rear motor speed not to exceed the rear motor speed limit.

[0012] In a second aspect, an embodiment of the present application provides a vehicle driving anti-slip control system, which comprises a processor, a memory, and a computer program stored in the memory and executable on the processor, and the processor implements the vehicle driving anti-slip control method of the first aspect when executing the computer program.

[0013] In a third aspect, an embodiment of the present application provides a vehicle comprising the vehicle driving anti-slip control system of the second aspect.

[0014] Compared with the prior art, the embodiment of the present application has the beneficial effects that: according to the collected current vehicle speed, left front wheel turning angle and right front wheel turning angle, in combination with the first real vehicle fixed parameter, the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed are determined, according to the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed, the front axle speed, the rear axle speed, the front axle speed difference and the rear axle speed difference are determined, the front axle speed and the rear axle speed are corrected to obtain the modified front axle speed and the modified rear axle speed, according to the actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference, the front axle speed difference and the rear axle speed difference are determined, according to the modified front axle speed, the modified rear axle speed, the front axle speed difference and the rear axle speed difference, in combination with the second real vehicle fixed parameter, the front motor speed limit and the rear motor speed limit are obtained, the current front motor speed and the current rear motor speed are real-time collected, and the current front motor speed is controlled not to exceed the front motor speed limit and the current rear motor speed is controlled not to exceed the rear motor speed limit, the calculated wheel speed is used to obtain the motor speed limit, and the slip condition is identified according to the limit, which has high precision and real-time performance, so that the control period of the motor can be shortened, and the precision of the anti-slip control is improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0016] Figure 1 is a structural schematic diagram of a four-wheel drive vehicle control system provided by an embodiment of the present application;

[0017] Figure 2 is a flowchart of a vehicle drive anti-slip control method provided by an embodiment of the present application;

[0018] Figure 3 is a principle schematic diagram of Ackerman steering calculation provided by an embodiment of the present application;

[0019] Figure 4 is a flowchart of torque distribution calculation provided by an embodiment of the present application;

[0020] Figure 5 is a structural schematic diagram of torque distribution calculation provided by an embodiment of the present application;

[0021] Figure 6 is a structural schematic diagram of vehicle information interaction provided by an embodiment of the present application;

[0022] Figure 7 is a structural schematic diagram of a vehicle drive anti-slip control system provided by an embodiment of the present application. DETAILED DESCRIPTION

[0023] In the following description, specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. However, persons skilled in the art will understand that the present application can be practiced without these specific details. In other instances, well-known structures, devices, circuits, and methods have not been described in detail in order to avoid obscuring the present application.

[0024] It should be understood that when used in the specification and the appended claims of the present application, the term "comprising" indicates the presence of the described features, integers, steps, operations, elements, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0025] In addition, in the description of the present application and the appended claims, the terms "first", "second", "third", etc. are used only to distinguish descriptions and cannot be understood as indicating or implying relative importance.

[0026] In the present application, the reference to "one embodiment" or "some embodiments" means that the specific features, structures or characteristics described in connection with the embodiment are included in one or more embodiments of the present application. Therefore, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in further some embodiments" and the like appearing in the present description are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. The terms "include", "contain", "have" and their variants mean "including but not limited to", unless otherwise specifically emphasized.

[0027] It should be understood that the size of the serial number of each step in the following embodiments does not mean the order of execution, and the execution order of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0028] In order to illustrate the technical solutions of the present application, the following will be described by specific embodiments.

[0029] Referring to Figure 1 is a structural schematic diagram of a four-wheel drive vehicle control system provided by Embodiment One of the present application. The four-wheel drive vehicle control system comprises a vehicle controller, a front motor, a front motor controller, a rear motor and a rear motor controller, wherein 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.

[0030] The vehicle controller cooperates with the controllers such as the front motor controller and the rear motor controller to realize the vehicle drive anti-slip control method of the present application.

[0031] The vehicle controller calculates the highest speed limit of the output drive motor according to the current four-wheel speed and other signals and sends it to the front / rear motor controller. The torque transfer amount of the front / rear axle is calculated according to the motor speed and the actual torque of the motor fed back by the front / rear motor controller and is sent to the front / rear motor controller, so as to realize the torque transfer between the front / rear axle. The vehicle controller serves as the coordination center of the entire control strategy and coordinates the work of each controller to ensure the orderly execution of the entire control strategy from the entire system.

[0032] The front / rear motor controller uses the target axle speed and the motor speed and combines the torque limit sent by the vehicle controller to perform PID adjustment for actual torque reduction control. The front / rear motor controller serves as the actuator in the entire control strategy and actually executes the torque and speed limit of the anti-slip control.

[0033] Referring to Figure 2 A flowchart of a vehicle driving anti-slip control method provided for Embodiment Two of the present application is shown in Figure 2 The vehicle driving anti-slip control method includes the following steps:

[0034] In step S201, the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed are determined according to the collected current vehicle speed, the left front wheel steering angle and the right front wheel steering angle, in combination with the first real vehicle fixed parameters.

[0035] In the present embodiment, the current vehicle speed is the vehicle speed information collected by a vehicle speed sensor at the current calculation time, the left front wheel steering angle is the angle information collected by an angle sensor installed at the left front wheel of the vehicle at the current calculation time, and the right front wheel steering angle is the angle information collected by an angle sensor installed at the right front wheel of the vehicle at the current calculation time. Of course, the steering angles of the front and rear wheels can also be obtained by conversion using the steering wheel steering angle. In this case, the left front wheel and the right front wheel may have different steering angles when steering.

[0036] The above vehicle speed can be the center of mass reference vehicle speed. Of course, under certain error conditions, it can also be a vehicle speed represented at other positions.

[0037] Optionally, the current vehicle speed is the center of mass reference vehicle speed, and the first real vehicle fixed parameters include the vehicle wheelbase, the vehicle track, the distance from the center of mass to the front axle and the distance from the center of mass to the rear axle.

[0038] According to the collected current vehicle speed, the left front wheel steering angle and the right front wheel steering angle, in combination with the first real vehicle fixed parameters, the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed are determined, including:

[0039] According to the collected left front wheel steering angle and the right front wheel steering angle, the steering direction is determined, and according to the steering direction and the Ackermann steering principle, the wheel speed calculation model is determined.

[0040] The collected current vehicle speed, the left front wheel steering angle, the right front wheel steering angle and the first real vehicle fixed parameters 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.

[0041] Among them, the four wheel speeds can be calculated according to the Ackermann steering principle, as shown in Figure 3As shown, it is a principle diagram of Ackerman steering calculation provided by the second embodiment of the application, wherein the input of the Ackerman steering calculation is the mass center reference vehicle speed V0, according to the corresponding relationship between the steering wheel angle and the front wheel angle (the same vehicle model is a fixed relationship designed), the left front wheel angle θ and the right front wheel angle φ can be obtained, the fixed parameters include the vehicle wheelbase L, the vehicle track B, the distance b of the mass center from the rear axle and the distance a of the mass center from the front axle, and the output of the Ackerman steering calculation is the left front wheel speed V1, the right front wheel speed V2, the left rear wheel speed V3 and the right rear wheel speed V4.

[0042] If the vehicle is left steering, the following formula is used for calculation:

[0043]

[0044]

[0045]

[0046]

[0047] If the vehicle is right steering, the following formula is used for calculation:

[0048]

[0049]

[0050]

[0051] .

[0052] The Ackerman steering principle is used to perform the calculation of the speed, rather than judging whether the vehicle is slipping according to the wheel speed sensor, compared with the low precision and low real-time of the wheel speed sensor, the above calculation method can obtain the speed with high precision and in real time.

[0053] In step S202, the front axle speed, the rear axle speed, the front axle speed difference and the rear axle speed difference are determined according to the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed, the front axle speed and the rear axle speed are corrected to obtain the corrected front axle speed and the corrected rear axle speed.

[0054] In the embodiment, the front axle speed and the front axle speed difference are determined by the left front wheel speed and the right front wheel speed, and the rear axle speed and the rear axle speed difference are determined by the left rear wheel speed and the right rear wheel speed.

[0055] The front axle speed and the rear axle speed correspond to a certain allowed slipping error range, therefore, the front axle speed and the rear axle speed can be corrected to obtain the front axle speed and the rear axle speed within a certain range.

[0056] Optionally, the front axle speed, the rear axle speed, the front axle speed difference and the rear axle speed difference are determined according to the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed, comprising:

[0057] The left front wheel speed and the right front wheel speed are averaged to obtain the average value as the front axle speed, and the left rear wheel speed and the right rear wheel speed are averaged to obtain the average value as the rear axle speed;

[0058] The left front wheel speed and the right front wheel speed are subtracted to obtain the difference value as the front axle speed difference, and the left rear wheel speed and the right rear wheel speed are subtracted to obtain the difference value as the rear axle speed difference.

[0059] The front / rear axle speed and the front / rear axle speed difference are calculated according to the following formula:

[0060] 、 、 、 ,

[0061] In the formula, represents the front axle speed, represents the rear axle speed, represents the front axle speed difference, represents the rear axle speed difference.

[0062] The front axle speed, the rear axle speed, the front axle speed difference and the rear axle speed difference are expressed in the above manner, which can obtain accurate speed and speed difference calculation results for subsequent calculation, and improve control accuracy.

[0063] Optionally, the front axle speed and the rear axle speed are corrected to obtain the corrected front axle speed and the corrected rear axle speed, comprising:

[0064] The front axle speed and the rear axle speed are compared to obtain the front / rear axle speed ratio, and the front / rear axle speed ratio is used to look up the preset slip speed lookup table to obtain a correction bias;

[0065] The correction bias is added to the front axle speed to obtain the corrected front axle speed, and the correction bias is added to the rear axle speed to obtain the corrected rear axle speed.

[0066] In the formula, the correction bias is the slip speed difference allowed by the control when slipping, and is obtained by looking up the slip speed lookup table according to the front axle speed and the rear axle speed respectively (specifically ), for example, the slip speed lookup table is Table 1 below:

[0067] Table 1

[0068]

[0069] The calculation formula for performing the correction calculation is as follows:

[0070] 、 ,

[0071] In the formula, represents the corrected front axle speed, represents the corrected rear axle speed.

[0072] The preset slip speed lookup table can configure corresponding errors for the slip to control the slip within an allowable range and improve the robustness of the control. The preset slip speed lookup table can be obtained through experiments or calibration, and different tables can be configured for each vehicle model to improve the pertinence of the vehicle.

[0073] In step S203, the front axle speed difference and the rear axle speed difference are determined according to the collected actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference, and the front motor speed limit and the rear motor speed limit are obtained according to the corrected front axle speed, the corrected rear axle speed, the front axle speed difference and the rear axle speed difference, and in combination with the second real vehicle fixed parameter.

[0074] In this embodiment, the current front / rear axle speed difference can be determined in combination with the actual wheel speeds of the four wheels and the front / rear axle speed difference determined in step S202, so as to be used for subsequent calculation of the front / rear motor speed limit. The front / rear motor speed limit is related to the front / rear axle speed and the front / rear axle speed difference.

[0075] Optionally, the front axle speed difference and the rear axle speed difference are determined according to the collected actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference, and the front axle speed difference and the rear axle speed difference are determined according to the collected actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference.

[0076] The actual wheel speed of the left front wheel and the actual wheel speed of the right front wheel are subtracted to obtain a first subtraction result, the first subtraction result is subtracted from the front axle speed difference to obtain a second subtraction result, and half of the absolute value of the second subtraction result is determined as the front axle speed difference;

[0077] The actual wheel speed of the left rear wheel and the actual wheel speed of the right rear wheel are subtracted to obtain a third subtraction result, the third subtraction result is subtracted from the rear axle speed difference to obtain a fourth subtraction result, and half of the absolute value of the fourth subtraction result is determined as the rear axle speed difference.

[0078] The front / rear axle speed difference calculation formula is as follows:

[0079] 、 ,

[0080] In the formula, represents the front axle speed difference, represents the rear axle speed difference, represents the actual wheel speed of the left front wheel, characterizing the actual wheel speed of the right front wheel, characterizing the actual wheel speed of the left rear wheel, characterizing the actual wheel speed of the right rear wheel.

[0081] The above calculation combines the actual wheel speed and the difference between the actual wheel speed and the theoretical speed, thereby obtaining the actual speed difference, which can effectively reflect the speed difference of the front and rear motors, thereby providing accurate prerequisite conditions for subsequent speed limitation.

[0082] Optionally, the second real vehicle fixed parameter includes a first speed ratio of the front motor to the wheel end, a second speed ratio of the rear motor to the wheel end, and a wheel tire radius;

[0083] 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, the front motor speed limitation and the rear motor speed limitation are obtained, including:

[0084] According to the corrected front axle speed, the front axle speed difference, the first speed ratio, and the wheel tire radius, the front motor speed limitation is obtained, wherein the sum of the corrected front axle speed and the front axle speed difference, the first speed ratio are positively correlated with the front motor speed limitation, and the wheel tire radius is inversely correlated with the front motor speed limitation;

[0085] According to the corrected rear axle speed, the rear axle speed difference, the second speed ratio, and the wheel tire radius, the rear motor speed limitation is obtained, wherein the sum of the corrected rear axle speed and the rear axle speed difference, the second speed ratio are positively correlated with the rear motor speed limitation, and the wheel tire radius is inversely correlated with the rear motor speed limitation.

[0086] The calculation formula of the front / rear motor speed limitation is as follows:

[0087] 、

[0088] In the formula, is the front motor speed limitation, is the rear motor speed limitation, r1 is the speed ratio of the front motor to the wheel end, r2 is the speed ratio of the front motor to the wheel end, and R is the wheel tire radius.

[0089] The above calculation can accurately reflect the speed limitation of the front motor and the rear motor, thereby enabling the subsequent judgment to determine whether the vehicle is slipping, i.e., considering that there is a slipping condition when the speed limitation is exceeded, and considering that there is no slipping when the speed limitation is not exceeded.

[0090] Step S204, real-time acquisition of the current speed of the front motor and the current speed of the rear motor, control of the current speed of the front motor not to exceed the front motor speed limitation and the current speed of the rear motor not to exceed the rear motor speed limitation.

[0091] In this embodiment, the current speed of the corresponding motor can be collected by the motor controller in real time, and the speed is compared with the above-mentioned speed limit. For the front motor, the current speed of the front motor is compared with the front motor speed limit. For the rear motor, the current speed of the rear motor is compared with the rear motor speed limit.

[0092] If the speed limit is exceeded, the output torque of the motor needs to be adjusted, so that the speed of the corresponding motor does not exceed the corresponding speed limit, to prevent the occurrence of skidding.

[0093] According to the collected current vehicle speed, left front wheel steering angle and right front wheel steering angle, the left front wheel speed, right front wheel speed, left rear wheel speed and right rear wheel speed are determined in combination with the first real vehicle fixed parameter. 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. 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 collected actual wheel speed of the four wheels, front axle speed difference and rear axle speed difference, 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, the front motor speed limit and rear motor speed limit are obtained in combination with the second real vehicle fixed parameter. The current front motor speed and current rear motor speed are collected in real time. The current front motor speed is controlled not to exceed the front motor speed limit, and the current rear motor speed is controlled not to exceed the rear motor speed limit. The calculated wheel speed is used to obtain the motor speed limit, and the limit is used to identify the skidding condition. It has high precision and real-time performance, so that the control period of the motor can be shortened, and the precision of the anti-skid control is improved.

[0094] Referring to Figure 4 , which is a flowchart of a torque distribution calculation provided in Embodiment Three of the present application. The process of how to control the motor not to exceed the corresponding speed limit is solved.

[0095] For controlling the current front motor speed not to exceed the front motor speed limit in step S204, it includes:

[0096] The collected front axle driver demand torque and rear axle torque transfer amount at the previous moment are summed to obtain the front axle demand torque;

[0097] If it is detected that the current front motor speed exceeds the front motor speed limit, a front axle torque reduction request torque is generated. The smaller value between the front axle torque reduction request torque and the front axle demand torque is determined as the front motor request torque, and the front motor outputs the front motor request torque;

[0098] The front axle driver demand torque is subtracted from the front motor request torque, and the obtained difference value is determined as the front axle torque transfer amount, which is transferred to the rear motor.

[0099] If it is detected that the current speed of the front motor does not exceed the speed limit of the front motor, the front motor is controlled to output the front axle demand torque.

[0100] In addition, for the control of the rear motor current speed not exceeding the rear motor speed limit in step S204, it includes:

[0101] The collected rear axle driver demand torque and rear axle torque transfer amount are summed to obtain the rear axle demand torque;

[0102] If it is detected that the current speed of the rear motor exceeds the speed limit of the rear motor, the rear axle torque reduction request torque is generated, the smaller value between the rear axle torque reduction request torque and the rear axle demand torque is determined as the rear motor request torque, and the rear motor is controlled to output the rear motor request torque;

[0103] The rear axle driver demand torque is subtracted from the rear motor request torque, and the obtained difference value is determined as the rear axle torque transfer amount, which is transferred to the front motor;

[0104] If it is detected that the current speed of the rear motor does not exceed the speed limit of the rear motor, the rear motor is controlled to output the rear axle demand torque.

[0105] Wherein, for the front motor, if the actual speed of the front motor exceeds the speed limit of the front motor, it is judged that the front axle torque reduction is activated, and for the rear motor, if the actual speed of the rear motor exceeds the speed limit of the rear motor, it is judged that the rear axle torque reduction is activated.

[0106] For the front axle, the front axle torque reduction request torque is tq_dec_fr=tq_FrMot_act*r1+offset1, wherein 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 calibration quantity, which is obtained by real vehicle calibration matching, for example, offset1 is 100 Nm.

[0107] For the rear axle, the rear axle torque reduction request torque is tq_dec_re=tq_ReMot_act*r2+offset2, wherein 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 calibration quantity, which is obtained by real vehicle calibration matching, for example, offset2 is 100 Nm.

[0108] The front motor request torque is tq_MotReq_fr, which is calculated as follows:

[0109] If front axle torque reduction is not activated, then tq_MotReq_fr = tq_DrvReq_fr + tq_tsf_re_old; if front axle torque reduction is activated, then tq_MotReq_fr = min(tq_dec_frtq_FrMot_act, (tq_DrvReq_fr + tq_tsf_re_old)); front axle torque transfer amount tq_tsf_fr = tq_DrvReq_fr - tq_MotReq_fr; where tq_DrvReq_fr is the front axle driver's required torque, and tq_tsf_re_old is the rear axle torque transfer amount calculated in the previous calculation cycle;

[0110] For the requested torque of the rear motor, tq_MotReq_re, it is calculated as follows:

[0111] If the rear axle torque reduction is not activated, then tq_MotReq_re = tq_DrvReq_fr + tq_tsf_fr; if the rear axle torque reduction is activated, then tq_MotReq_re = min(tq_dec_retq_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 rear axle driver's required torque, and tq_tsf_fr is the front axle torque transfer amount calculated in the current calculation cycle.

[0112] Accordingly, such as Figure 5 The diagram shown is a flowchart of a torque distribution calculation provided in Embodiment 4 of this application. In this diagram, the front axle torque reduction and rear axle torque reduction are not activated, that is, the current speed of the front / rear motors exceeds the corresponding speed limit.

[0113] like Figure 6 The diagram shown is a structural schematic of vehicle information interaction according to Embodiment 5 of this application. Specifically, the vehicle controller is used to implement limit calculations and torque distribution, while the front / rear motor controllers are used to determine whether to reduce torque and to calculate the torque after reduction. Different algorithms are embedded into the vehicle controller and the front / rear motor controllers respectively to shorten the control cycle and prevent the instability 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, resulting in accurate torque and high real-time performance.

[0114] like Figure 7As shown in the figure, the structure diagram of the vehicle driving anti-slip control system provided in the embodiment six of the present application is shown, and the central control device belongs to the vehicle driving anti-slip control system, which comprises a processor, a memory, and a computer program stored in the memory and executable on the processor, and the processor implements the vehicle driving anti-slip control method recorded in the above embodiments when executing the computer program. When there is more than one processor, it can correspond to the vehicle controller, the front motor controller and the rear motor controller, etc.

[0115] In addition, the embodiment of the present application further provides a vehicle comprising the vehicle driving anti-slip control system in the above embodiments.

[0116] Those skilled in the art can understand that, Figure 7 The vehicle driving anti-slip control system is only an example and does not limit the computer device, which can include more or fewer components than the figure, or combine certain components, or different components.

[0117] The processor can be a CPU, and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0118] The memory comprises a readable storage medium, an internal memory, etc., wherein the internal memory can be the memory of the computer device, and the internal memory provides an environment for the operation of the operating system and the computer readable instructions in the readable storage medium. The readable storage medium can be the hard disk of the computer device, and in other embodiments, it can also be the external storage device of the computer device, such as the plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. Further, the memory can include both the internal storage unit of the computer device and the external storage device. The memory is used to store the operating system, application programs, boot loader, data and other programs, such as the program code of the computer program. The memory can also be used to temporarily store the data that has been output or will be output.

[0119] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in a certain embodiment can be referred to the relevant description of other embodiments.

[0120] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0121] In the embodiments provided in the present application, it should be understood that the disclosed apparatus / control device and method can be implemented in other ways. For example, the apparatus / control device embodiments described above are merely illustrative, for example, the division of modules or units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed units can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0122] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or they can be distributed on multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiments according to actual needs.

[0123] The above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A vehicle drive slip control method, characterized by, The method comprises the following steps: determining the left front wheel speed, the right front wheel speed, the left rear wheel speed and the right rear wheel speed according to the collected current vehicle speed, the left front wheel steering angle and the right front wheel steering angle, in combination with the first real vehicle fixed parameters; determining the front axle speed difference and the rear axle speed difference according to the actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference, and 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 parameters; real-time collecting the current front motor speed and the current rear motor speed, and controlling the current front motor speed not to exceed the front motor speed limit and the current rear motor speed not to exceed the rear motor speed limit; determining the front axle speed difference and the rear axle speed difference according to the actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference, and 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 parameters; determining the front axle speed difference and the rear axle speed difference according to the actual wheel speeds of the four wheels, the front axle speed difference and the rear axle speed difference, and 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 parameters; The current vehicle speed is a mass center reference vehicle speed, and the first real vehicle fixed parameters include a vehicle wheelbase, a vehicle track, a mass center distance from a front axle and a mass center distance from a rear axle. The method comprises the following steps: determining a steering direction according to the collected left front wheel steering angle and right front wheel steering angle, and determining a wheel speed calculation model according to the steering direction and the Ackerman steering principle; inputting the collected current vehicle speed, left front wheel steering angle, right front wheel steering angle and first real vehicle fixed parameters into the wheel speed calculation model, and outputting the left front wheel speed, right front wheel speed, left rear wheel speed and right rear wheel speed.

2. The vehicle drive slip control method according to claim 1, characterized by, The method comprises the following steps: ​ ​ ​ 3. The vehicle drive slip control method according to claim 1, characterized by, ​ The left front wheel speed and the right front wheel speed are averaged to obtain a front axle speed, and the left rear wheel speed and the right rear wheel speed are averaged to obtain a rear axle speed.

4. The vehicle drive slip control method according to claim 1, characterized by, The front axle speed and the rear axle speed are corrected to obtain a corrected front axle speed and a corrected rear axle speed, including: The front axle speed and the rear axle speed are compared to obtain a front-rear axle speed ratio, and a correction bias is obtained from a preset slip speed lookup table according to the front-rear axle speed ratio; The correction bias is added to the front axle speed to obtain a corrected front axle speed, and the correction bias is added to the rear axle speed to obtain a corrected rear axle speed.

5. The vehicle drive slip control method according to claim 1, characterized by, The second real vehicle fixed parameters include a first speed ratio of the front motor to the wheel end, a second speed ratio of the rear motor to the wheel end, and a wheel tire radius; The corrected front axle speed, the corrected rear axle speed, the front axle speed difference, and the rear axle speed difference are combined with the second real vehicle fixed parameters to obtain a front motor speed limit and a rear motor speed limit, including: The corrected front axle speed, the front axle speed difference, the first speed ratio, and the wheel tire radius are used to obtain a front motor speed limit, wherein the sum of the corrected front axle speed and the front axle speed difference, the first speed ratio are positively correlated with the front motor speed limit, and the wheel tire radius is inversely correlated with the front motor speed limit; The corrected rear axle speed, the rear axle speed difference, the second speed ratio, and the wheel tire radius are used to obtain a rear motor speed limit, wherein the sum of the corrected rear axle speed and the rear axle speed difference, the second speed ratio are positively correlated with the rear motor speed limit, and the wheel tire radius is inversely correlated with the rear motor speed limit.

6. The vehicle drive slip control method according to claim 1, characterized by The current front motor speed is controlled not to exceed the front motor speed limit, including: The front axle driver demand torque and the rear axle torque transfer amount at the previous time are summed to obtain a front axle demand torque; If it is detected that the current front motor speed exceeds the front motor speed limit, a front axle torque reduction request torque is generated, the smaller value between the front axle torque reduction request torque and the front axle demand torque is determined as a front motor request torque, and the front motor outputs the front motor request torque; The front axle driver demand torque and the front motor request torque are subtracted to obtain a front axle torque transfer amount, and the front axle torque transfer amount is transferred to the rear motor; If it is detected that the current front motor speed does not exceed the front motor speed limit, the front motor outputs the front axle demand torque.

7. The vehicle drive slip control method according to claim 6, characterized by, The current rear motor speed is controlled not to exceed the rear motor speed limit, including: The rear axle driver demand torque and the rear axle torque transfer amount are summed to obtain a rear axle demand torque; If it is detected that the current rear motor speed exceeds the rear motor speed limit, a rear axle torque reduction request torque is generated, the smaller value between the rear axle torque reduction request torque and the rear axle demand torque is determined as a rear motor request torque, and the rear motor outputs the rear motor request torque; determining a difference between the rear axle driver demand torque and the rear electric machine request torque, and determining a rear axle torque transfer amount based on the difference; if it is detected that the current speed of the rear electric machine does not exceed the rear electric machine speed limit, controlling the rear electric machine to output the rear axle demand torque.

8. A vehicle drive slip control system characterized by comprising: A vehicle drive anti-slip control system comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the vehicle drive anti-slip control method according to any one of claims 1 to 7 when executing the computer program.

9. A vehicle characterized by comprising: A vehicle drive anti-slip control system according to claim 8.

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