Centralized driving electric unmanned vehicle driving anti-skid control system based on EPB

Abstract

The invention provides an EPB-based driving anti-skid control system for a centralized driving electric unmanned vehicle. The system comprises a vehicle control unit VCU, a motor controller MCU, a driving motor, a differential mechanism and an electro-hydraulic braking system EHB, and the vehicle control unit VCU controls the motor controller MCU and an EPB controller through CAN communication; the EPB controller controls the left EPB and the right EPB, the left EPB is connected with the left rear driving wheel, and the right EPB is connected with the right rear driving wheel; the left rear driving wheel, the right rear driving wheel, the left front driven wheel and the right front driven wheel are each provided with a wheel speed sensor. The left front driven wheel and the right front driven wheel are connected with an electric power steering (EPS) and are controlled by an EPS controller, and the left rear driving wheel and the right rear driving wheel are connected into a differential mechanism; and the system calculates the slip rate of the driving wheel, compares the slip rate with a set slip rate threshold value, judges the slip condition, and performs execution control. And compared with traditional mechanical parking braking, use of a mechanical structure is reduced, and driving anti-skid control can be conducted according to different working conditions.

Description

Technical Field

[0001] The present application belongs to the field of electric vehicle control, and in particular to an EPB-based centralized drive electric unmanned vehicle anti-skid control system. Background Art

[0002] As an important component of the active safety system of automobiles, the anti-skid drive control system has always been the focus of automobile dynamics research. According to data, when the vehicle is starting or accelerating, if the friction coefficient of the road surface is low, excessive driving force may cause serious slippage of the drive wheels. This situation will not only weaken the driving efficiency of the vehicle, but also may cause loss of control in front-wheel drive vehicles, and may cause the vehicle to drift in rear-wheel drive vehicles. Especially in severe weather conditions such as rain, snow, and hail, or when the vehicle is turning, the slip of the wheels is more likely to cause the vehicle to lose stability, thereby causing traffic accidents. Therefore, the role of the anti-skid drive control system is to prevent the drive wheels from slipping when driving on slippery or ice-covered roads with low friction coefficients, so as to ensure the stability and safety of the vehicle.

[0003] In the field of low-speed centralized drive electric unmanned vehicles, vehicles will also experience tire slippage. Vehicle slippage and difficulty in getting out of trouble should be considered as a condition for low-speed centralized drive electric unmanned vehicles. In centralized drive electric vehicles, open differentials are usually used to transmit the driving force from the drive motor. The core function of the open differential is to allow the inner and outer wheels of the vehicle to rotate at different speeds when turning to adapt to different driving path lengths. This design is difficult to deal with wheel slippage, and its working principle leads to an unbalanced distribution of power under certain conditions. In the case of one-sided slippage, due to the open differential, the slipping wheel rotates at high speed due to low grip, while the wheel on the other side can hardly turn due to insufficient power, making it difficult for the vehicle to get out of trouble under slipping conditions.

[0004] At present, the driving anti-skid strategy based on the vehicle body electronic stability system is to ensure that the vehicle has good driving performance and safety under various road conditions by controlling engine output, braking and torque distribution. When the system detects that the slip rate of the driving wheel exceeds a certain threshold, indicating that the wheel begins to slip, the system will automatically intervene and take the following measures: reduce the output torque of the engine, thereby reducing the driving force of the wheel to prevent further slipping. Apply braking force to the driving wheel that has slipped to restore the grip of the wheel by reducing the slip rate. In a four-wheel drive vehicle, more torque can be distributed to the non-slipping wheels as needed to improve the overall driving stability of the vehicle. However, the ESC control solution is costly and has high layout requirements. On the one hand, the ESC system requires multiple high-precision sensors, such as steering wheel angle sensors, yaw rate sensors, acceleration sensors, wheel speed sensors, etc. These sensors must have high accuracy and response speed to accurately monitor the vehicle's posture and motion state, so the procurement and installation costs are high. On the other hand, in order to ensure the control accuracy and response speed of the ESC system, sensors need to be installed in specific locations. For example, the yaw rate sensor needs to be located near the center of mass of the vehicle, which places high demands on the vehicle's layout space. On some models, the layout of these sensors may require additional improvements to the body structure. Summary of the invention

[0005] The application embodiment provides a centralized drive electric unmanned vehicle anti-skid control system based on EPB to solve the problems existing in the related technology. The technical solution is as follows: a centralized drive electric unmanned vehicle anti-skid control system based on EPB, including a vehicle controller VCU, a motor controller MCU, a drive motor, a differential, and an electro-hydraulic brake system EHB. The vehicle controller VCU controls the motor controller MCU and the EPB controller through CAN communication; the EPB controller controls the left EPB and the right EPB, the left EPB is connected to the left rear drive wheel, and the right EPB is connected to the right rear drive wheel;

[0006] The left rear driving wheel, right rear driving wheel, left front driven wheel and right front driven wheel are all equipped with wheel speed sensors;

[0007] The left front driven wheel and the right front driven wheel are connected to the electric power steering system EPS and controlled by the EPS controller, and the left rear driving wheel and the right rear driving wheel are connected to the differential;

[0008] The system calculates the driving wheel slip rate, compares it with the set slip rate threshold, determines the slip situation, and finally executes control based on the slip situation.

[0009]

[0010] Where: xis the rotation speed of a wheel, r is the wheel radius, and v is the current vehicle speed. The wheel speed value obtained from the wheel speed sensor signal of this wire-controlled chassis has been calculated to be the linear speed, that is, ω x r result;

[0011] Because the driving mode of this wire-controlled chassis is rear-wheel drive, the average of the speeds of the two driven wheels, namely the front wheels, is used to represent the current vehicle speed;

[0012]

[0013] Where: v FL is the linear speed of the left front wheel, v FR is the linear velocity of the right front wheel, and v is the current vehicle speed. Combining formula (2) with formula (1), we can get the slip rate of the two rear wheels, i.e., the two driving wheels, which is recorded as the left rear wheel slip rate s RL and the right rear wheel slip rate s RR .

[0014] Furthermore, under straight-line driving conditions, an expected slip rate threshold s is set x , according to the left rear wheel slip rate s RL and the right rear wheel slip rate s RR Determine that the maximum value is greater than the slip rate threshold s x When the vehicle is in a slipping state, it is judged that the vehicle is slipping. The slipping conditions are divided into single-side slipping and double-side slipping. After the longitudinal slipping condition is screened out, the corresponding driving anti-skid strategy is implemented.

[0015] When no speed request and steering angle request are received, that is, the vehicle is not in a lateral state, the longitudinal driving anti-skid protection function is entered.

[0016] Furthermore, the control strategy under the left driving wheel slip condition is: after the initialization is completed, the dual driving wheel slip condition is judged; when the left rear wheel slip rate s RL and the right rear wheel slip rate s RR Not greater than the longitudinal slip rate threshold s x When , it is considered that the single-side driving wheel is slipping. At this time, according to the design, the logic control is performed:

[0017] When it is determined that the left driving wheel is slipping, a first-order torque reduction is performed after initialization. If the road conditions are not too different, the slip of the left wheel may be effectively resolved after the first-order torque reduction. However, if the left wheel is still in a unilateral slip situation after the first-order torque reduction, in order to improve the effectiveness of the execution method, the left EPB is controlled to perform clamping control, and on the basis of torque reduction, braking force is applied in a direction, which is also a part of the drive anti-skid control strategy. If the slip situation does not change after applying the braking force, the second-order torque reduction is continued, and further, the third-order torque reduction control is performed. At the same time, during the execution of the strategy, if it is determined that the working condition has changed to dual driving force slip and right-side slip, switch to the corresponding anti-skid control for drive anti-skid.

[0018] Furthermore, the control strategy under the right driving wheel slip condition is: after the initialization is completed, the dual driving wheel slip condition is judged. When the right rear wheel slip rate SRR is greater than the longitudinal slip rate threshold s x , while the left rear wheel slip rate s RL Not greater than the longitudinal slip rate threshold s x , it is considered that the right driving wheel is slipping at this time. At this time, according to the design, the logic control is performed:

[0019] When it is determined that the right driving wheel is slipping, after initialization, a first-order torque reduction is performed. If the road conditions are not too different, the slip of the right wheel may be effectively resolved after the first-order torque reduction. However, if the right wheel is still in a unilateral slip after the first-order torque reduction, in order to improve the effectiveness of the execution method, the right EPB is controlled to perform clamping control. On the basis of torque reduction, braking force is applied in a direction, which is also a part of the drive anti-skid control strategy. If the slip situation does not change after applying the braking force, the second-order torque reduction will continue to be performed, and further, the third-order torque reduction control will be performed. At the same time, during the execution of the strategy, if it is determined that the working condition has changed to dual driving force slip and right-side slip, switch to the corresponding anti-skid control for drive anti-skid.

[0020] When a lateral motion state signal is received, that is, there is a lateral request value, the current lateral angle fed back by the current electronic power steering system (EPS) is not 0, that is, it is currently in a lateral state, and enters the lateral driving anti-skid protection function:

[0021] Furthermore, after the lateral slip is determined, the system performs a slip condition determination. When the left rear wheel slip rate s RL and the right rear wheel slip rate s RR When the maximum value of is greater than the lateral slip rate threshold, torque reduction logic control is performed:

[0022] After determining that there is drive wheel slip in lateral slip, a first-order torque reduction is performed after a set waiting time. At this time, it is considered that the drive wheel is slipping. At this time, the output torque of the drive motor is too large, the wheel-side driving force transmitted to the wheel is large, and the road adhesion is difficult to match the current drive torque. The torque reduction operation should be performed to limit the current output torque requested to the motor controller; after the first-order torque reduction, wait for a certain period of time. If double-wheel slip still exists at this time, a second-order torque reduction is performed. Similarly, a third-order torque reduction is performed; during the execution of the torque reduction command, if the drive anti-skid type is identified to be switched to longitudinal drive anti-skid mode, the longitudinal drive anti-skid control content is entered, in which the slip of the left and right wheels is further determined.

[0023] Furthermore, when the vehicle slips, if it enters the lateral drive anti-skid mode, it is necessary to gradually release the torque reduction and EPB control instructions of the previous longitudinal drive anti-skid mode. That is, after entering the lateral drive anti-skid mode from the longitudinal drive anti-skid mode, if there is EPB clamping control during longitudinal drive anti-skid control, the EPB clamping control is released in sequence to control the release of the third-order torque reduction instruction, the release of the second-order torque reduction instruction and the release of the first-order torque reduction instruction; after the initialization is completed, the lateral drive anti-skid control is performed, and the release of the torque reduction instruction will cancel the torque reduction instructions of each level of the previous longitudinal working condition in sequence.

[0024] Furthermore, when the vehicle slips and enters the longitudinal drive anti-skid mode, it is necessary to gradually release the torque reduction and EPB control instructions of the previous lateral drive anti-skid mode. That is, after entering the longitudinal drive anti-skid mode from the lateral drive anti-skid mode, if there is no EPB clamping control, the third-order torque reduction instruction, the second-order torque reduction instruction and the first-order torque reduction instruction are directly released in sequence. That is, the longitudinal drive anti-skid control is performed after the initialization is completed. Releasing the torque reduction instruction will cancel the torque reduction instructions of each level of the previous lateral working condition in sequence.

[0025] The advantages or beneficial effects of the above technical solution include:

[0026] (1) Compared with traditional mechanical parking brakes, this application reduces the use of mechanical structures, such as cables and pedals, and overall reduces manufacturing complexity, reduces dependence on mechanical components, and reduces maintenance costs. The EPB driving anti-skid strategy can be adaptively adjusted according to different road conditions, vehicle loads and other conditions to ensure vehicle stability. Especially in complex working conditions such as turning, emergency braking, and low adhesion, it effectively reduces the risk of skidding and side sliding, and improves the safety of vehicle driving.

[0027] (2) The electronic components and actuators of the present application, such as motors and electronic control units, are more compact than traditional braking systems and have greater flexibility in layout: they allow the electronic parking module to be arranged in a suitable spatial location, such as under the vehicle or near the rear axle, saving space in the vehicle and improving layout efficiency.

[0028] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0030] Figure 1 A schematic diagram of the control system architecture for driving the anti-skid function of this application;

[0031] Figure 2 This is a schematic diagram of the control architecture of the driving anti-skid function for this application;

[0032] Figure 3 This is the left driving wheel anti-skid control flow chart for this application;

[0033] Figure 4 This is the right driving wheel anti-skid control flow chart for this application;

[0034] Figure 5 This is the flow chart of lateral drive anti-skid control for this application;

[0035] Figure 6 Vertical switching horizontal control flow chart;

[0036] Figure 7 Flowchart of horizontal to vertical control switching. DETAILED DESCRIPTION

[0037] In the following, only some exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and descriptions are considered to be illustrative and non-restrictive in nature.

[0038] like Figure 1 As shown, a centralized drive electric unmanned vehicle anti-skid control system based on EPB includes a vehicle controller VCU, a motor controller MCU, a drive motor, a differential, and an electro-hydraulic brake system EHB. The vehicle controller VCU controls the motor controller MCU and the EPB controller through CAN communication; the EPB controller controls the left EPB and the right EPB, the left EPB is connected to the left rear drive wheel, and the right EPB is connected to the right rear drive wheel;

[0039] The left rear driving wheel, right rear driving wheel, left front driven wheel and right front driven wheel are all equipped with wheel speed sensors;

[0040] The left front driven wheel and the right front driven wheel are connected to the electric power steering system EPS and controlled by the EPS controller, and the left rear driving wheel and the right rear driving wheel are connected to the differential. Figure 2 As shown, the system calculates the driving wheel slip rate, compares it with the set slip rate threshold, determines the slip situation, and finally performs execution control according to the slip situation:

[0041] Slip rate calculation formula:

[0042]

[0043] Where: x is the rotation speed of a wheel, r is the wheel radius, and v is the current vehicle speed. The wheel speed value obtained from the wheel speed sensor signal of this wire-controlled chassis has been calculated to be the linear speed, that is, ω x The result of r.

[0044] Because the driving mode of the wire-controlled chassis is rear-wheel drive, the average of the speeds of the two driven wheels, namely the front wheels, is used to represent the current vehicle speed.

[0045]

[0046] Where: v FL is the linear speed of the left front wheel, v FR is the linear velocity of the right front wheel, and ν is the current vehicle speed. Combining formula (2) with formula (1), we can get the slip rate of the two rear wheels, i.e., the two driving wheels, which is recorded as the left rear wheel slip rate s RL and the right rear wheel slip rate s RR .

[0047] Under straight-line driving conditions, set an expected slip rate threshold s x , according to the left rear wheel slip rate s RL and the right rear wheel slip rate s RR Determine that the maximum value is greater than the slip rate threshold s x When the vehicle is judged to be skidding, the skidding condition is divided into single-side skidding and double-side skidding. After the longitudinal skidding condition is screened out, the corresponding driving anti-skid strategy is implemented.

[0048] When no speed request and steering angle request are received, that is, the vehicle is not in a lateral state, the longitudinal driving anti-skid protection function is entered.

[0049] (1) Left drive wheel slipping condition

[0050] like Figure 3As shown, after the initialization is completed, the dual drive wheel slip situation is judged. RL and the right rear wheel slip rate s RR Not greater than the longitudinal slip rate threshold s x It is considered that the single-side driving wheel is slipping at this time, and logical control is performed according to the design.

[0051] Since this drive-by-wire chassis uses an open differential, when the slippage of one side of the wheel is extreme, that is, when the road load on the left wheel is too low and the slippage is relatively serious, the differential may take away most of the power or even all of the power, causing the power of the other side wheel to be too low. If you only rely on reducing the output torque, it may be difficult to restore the power of the car, that is, the adhesion coefficient of the road surface on the slipping side is very low, and the driving force is adjusted to a lower value, but it still cannot be driven. Therefore, this control strategy is aimed at the drive-by-wire chassis of the electric unmanned vehicle, and controls the left and right EPBs used for parking. Under certain circumstances, it acts as an actuator for different braking forces on the left and right wheels, and uses the electronic parking brake system EPB to help the centralized drive drive-by-wire chassis realize that the wheel-side driving torque of the single-sided drive wheel can be different.

[0052] When it is determined that the left driving wheel is slipping, a first-order torque reduction is performed after initialization. If the road conditions are not too different, the slip of the left wheel may be effectively resolved after the first-order torque reduction. However, if the left wheel is still in a unilateral slip after the first-order torque reduction, in order to improve the effectiveness of the execution method, the left EPB is controlled to perform clamping control. On the basis of torque reduction, braking force is applied in a direction, which is also a part of the drive anti-skid control strategy. If the slip situation does not change after applying the braking force, the second-order torque reduction is continued, and further, the third-order torque reduction control is performed. The subsequent torque reduction is mainly to take into account the situation where the driving force is too large and the braking force provided by the EPB is limited. At the same time, during the execution of the strategy, if it is determined that the working condition has changed to dual driving force slip and right-side slip, the corresponding anti-skid control is switched to perform drive anti-skid.

[0053] (2) Right drive wheel slipping condition

[0054] After initialization is completed, the dual drive wheel slip situation is judged. When the right rear wheel slip rate SRR is greater than the longitudinal slip rate threshold Sx, and the left rear wheel slip rate SRL is not greater than the longitudinal slip rate threshold Sx, it is considered that the right drive wheel is slipping at this time, and logical control is performed according to the design.

[0055] like Figure 4As shown, when it is determined that the right driving wheel is slipping, after initialization, a first-order torque reduction is performed. If the difference in road conditions is not too large, the slip of the right wheel may be effectively relieved after the first-order torque reduction. However, if the right wheel is still in a unilateral slip after the first-order torque reduction, in order to improve the effectiveness of the execution method, the right EPB is controlled to perform clamping control. On the basis of torque reduction, the braking force is applied in a directional manner, which is also part of the drive anti-skid control strategy. If the slip situation still does not change after the braking force is applied, the second-order torque reduction is continued, and further, the third-order torque reduction control is performed. The subsequent torque reduction is mainly to take into account the situation where the driving force is too large and the braking force provided by the EPB is limited; at the same time, during the execution of the strategy, if it is determined that the working condition has changed to dual driving force slip and right-side slip, it will switch to the corresponding anti-skid control for drive anti-skid.

[0056] When a lateral motion state signal is received, that is, there is a lateral request value, the current lateral angle fed back by the current electronic power steering system (EPS) is not 0, that is, it is currently in a lateral state, and enters the lateral driving anti-skid protection function:

[0057] Since the EPB intervention in the control strategy during unilateral slippage may have a certain impact on the stability of the vehicle body in the lateral state, the driving anti-skid is divided into two conditions: longitudinal and lateral. The focus is on the identification and control of the longitudinal working condition, and the lateral working condition adopts a certain logic. When entering the lateral working condition, the driving anti-skid logic during straight-line driving needs to be reset.

[0058] After the lateral slip is determined, the slip condition is determined. RL and the right rear wheel slip rate s RR When the maximum value of is greater than the lateral slip rate threshold, torque reduction logic control is performed.

[0059] like Figure 5 As shown, after determining that the lateral slip has caused the drive wheel to slip, after a set waiting time, a first-order torque reduction is performed. At this time, it is considered that the drive wheel has slipped. At this time, the output torque of the drive motor is too large, the wheel side driving force transmitted to the wheel is large, and the road adhesion is difficult to match the current driving torque. A torque reduction operation should be performed to limit the current output torque requested to the motor controller. After the first-order torque reduction, wait for a certain period of time. If there is still double-wheel slip at this time, a second-order torque reduction is performed. Similarly, a third-order torque reduction is performed. During the execution of the torque reduction command, if the drive anti-skid type is identified to switch to the longitudinal drive anti-skid mode, the longitudinal drive anti-skid control content is entered, in which the left and right wheel slip conditions are further determined.

[0060] In particular, if Figure 6As shown in the figure, when the vehicle skids, if the lateral drive anti-skid mode is entered, the torque reduction and EPB control instructions of the previous longitudinal drive anti-skid mode need to be gradually released, that is, after entering the lateral drive anti-skid mode from the longitudinal drive anti-skid mode, if there is EPB clamping control during longitudinal drive anti-skid control, the EPB clamping control is released in sequence, and the control releases the third-order torque reduction instruction, the second-order torque reduction instruction, and the first-order torque reduction instruction. After initialization is completed, the lateral drive anti-skid control is performed. Releasing the torque reduction instruction will cancel the torque reduction instructions of each level of the previous longitudinal working condition in sequence.

[0061] In particular, if Figure 7 As shown, when the vehicle slips, when the longitudinal drive anti-skid mode is entered, the torque reduction and EPB control instructions of the previous lateral drive anti-skid mode need to be gradually released, that is, after entering the longitudinal drive anti-skid mode from the lateral drive anti-skid mode, if there is no EPB clamping control, the third-order torque reduction instruction, the second-order torque reduction instruction and the first-order torque reduction instruction are directly released in sequence, that is, the longitudinal drive anti-skid control is performed after the initialization is completed, and the release of the torque reduction instruction will cancel the torque reduction instructions of each level of the previous lateral working condition in sequence.

[0062] The embodiments of the present disclosure have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein. Therefore, the scope of protection of the present application shall be based on the scope of protection of the claims.

Claims

1. A centralized drive electric unmanned vehicle anti-skid control system based on EPB, including a vehicle controller VCU, a motor controller MCU, a drive motor, a differential, and an electro-hydraulic brake system EHB. The vehicle controller VCU controls the motor controller MCU and the EPB controller through CAN communication; the EPB controller controls the left EPB and the right EPB, the left EPB is connected to the left rear drive wheel, and the right EPB is connected to the right rear drive wheel; The left rear driving wheel, right rear driving wheel, left front driven wheel and right front driven wheel are all equipped with wheel speed sensors; The left front driven wheel and the right front driven wheel are connected to the electric power steering system EPS and controlled by the EPS controller, and the left rear driving wheel and the right rear driving wheel are connected to the differential; The system calculates the driving wheel slip rate, compares it with the set slip rate threshold, determines the slip situation, and finally executes control based on the slip situation.

2. According to claim 1, a centralized drive electric unmanned vehicle anti-skid control system based on EPB is characterized in that: The slip rate calculation formula is: Where: x is the rotation speed of a wheel, r is the wheel radius, and ν is the current vehicle speed. The wheel speed value obtained from the wheel speed sensor signal of this wire-controlled chassis has been calculated to be the linear speed, that is, ω x r result; Because the driving mode of this wire-controlled chassis is rear-wheel drive, the average of the speeds of the two driven wheels, namely the front wheels, is used to represent the current vehicle speed; Where: v FL is the linear velocity of the left front wheel, ν FR is the linear velocity of the right front wheel, v is the current vehicle speed; by combining formula (2) and formula (1), we can get the slip rate of the two rear wheels, i.e., the two driving wheels, which is recorded as the left rear wheel slip rate s RL and the right rear wheel slip rate s RR .

3. The EPB-based centralized drive electric unmanned vehicle anti-skid control system according to claim 2 is characterized in that: Under straight-line driving conditions, set an expected slip rate threshold s x , according to the left rear wheel slip rate s RL and the right rear wheel slip rate s RR Determine that the maximum value is greater than the slip rate threshold s x When the vehicle is in a slipping state, it is judged that the vehicle is slipping. The slipping conditions are divided into single-side slipping and double-side slipping. After the longitudinal slipping condition is screened out, the corresponding driving anti-skid strategy is implemented. When no speed request and steering angle request are received, that is, the vehicle is not in a lateral state, the longitudinal driving anti-skid protection function is entered.

4. The EPB-based centralized electric unmanned vehicle anti-skid control system according to claim 2 is characterized in that: The control strategy under the left driving wheel slip condition is: after the initialization is completed, the dual driving wheel slip situation is judged; when the left rear wheel slip rate s RL and the right rear wheel slip rate s RR Not greater than the longitudinal slip rate threshold s x When , it is considered that the single-side driving wheel is slipping. At this time, according to the design, the logic control is performed: When it is determined that the left driving wheel is slipping, a first-order torque reduction is performed after initialization. If the road conditions are not too different, the slip of the left wheel may be effectively resolved after the first-order torque reduction. However, if the left wheel is still in a unilateral slip situation after the first-order torque reduction, in order to improve the effectiveness of the execution method, the left EPB is controlled to perform clamping control, and on the basis of torque reduction, braking force is applied in a direction, which is also a part of the drive anti-skid control strategy. If the slip situation does not change after applying the braking force, the second-order torque reduction is continued, and further, the third-order torque reduction control is performed. At the same time, during the execution of the strategy, if it is determined that the working condition has changed to dual driving force slip and right-side slip, switch to the corresponding anti-skid control for drive anti-skid.

5. The EPB-based centralized drive electric unmanned vehicle anti-skid control system according to claim 2 is characterized in that: The control strategy under the right driving wheel slip condition is: after the initialization is completed, the dual driving wheel slip situation is judged. When the right rear wheel slip rate SRR is greater than the longitudinal slip rate threshold s x , while the left rear wheel slip rate s RL Not greater than the longitudinal slip rate threshold s x When the right driving wheel is considered to be slipping, the following logic control is performed according to the design: When it is determined that the right driving wheel is slipping, after initialization, the first-order torque reduction is performed. If the difference in road conditions is not too large, the slip of the right wheel may be effectively resolved after the first-order torque reduction. However, if the right wheel is still in a unilateral slip after the first-order torque reduction, in order to improve the effectiveness of the execution method, the right EPB is controlled to perform clamping control. On the basis of torque reduction, the braking force is applied in a directional manner, which is also a part of the drive anti-skid control strategy. If the slip situation does not change after the braking force is applied, the second-order torque reduction is continued, and further, the third-order torque reduction control is performed. At the same time, during the execution of the strategy, if it is determined that the working condition has changed to dual driving force slip and right-side slip, it is switched to the corresponding anti-skid control for drive anti-skid: When a lateral motion state signal is received, that is, there is a lateral request value, the current lateral angle fed back by the current electronic power steering system (EPS) is not 0, that is, it is currently in a lateral state and enters the lateral driving anti-skid protection function.

6. The EPB-based centralized electric unmanned vehicle anti-skid control system according to claim 2, characterized in that: After the system determines the lateral slip, it will determine the slip situation. When the left rear wheel slip rate s RL and the right rear wheel slip rate s RR When the maximum value of is greater than the lateral slip rate threshold, torque reduction logic control is performed: After determining that there is drive wheel slip in lateral slip, a first-order torque reduction is performed after a set waiting time. At this time, it is considered that the drive wheel is slipping. At this time, the output torque of the drive motor is too large, the wheel-side driving force transmitted to the wheel is large, and the road adhesion is difficult to match the current drive torque. The torque reduction operation should be performed to limit the current output torque requested to the motor controller; after the first-order torque reduction, wait for a certain period of time. If double-wheel slip still exists at this time, a second-order torque reduction is performed. Similarly, a third-order torque reduction is performed; during the execution of the torque reduction command, if the drive anti-skid type is identified to be switched to longitudinal drive anti-skid mode, the longitudinal drive anti-skid control content is entered, in which the slip of the left and right wheels is further determined.

7. The EPB-based centralized electric unmanned vehicle anti-skid control system according to claim 6, characterized in that: When the vehicle slips, if it enters the lateral drive anti-skid mode, it is necessary to gradually release the torque reduction and EPB control instructions of the previous longitudinal drive anti-skid mode. That is, after entering the lateral drive anti-skid mode from the longitudinal drive anti-skid mode, if there is EPB clamping control during longitudinal drive anti-skid control, the EPB clamping control should be released in sequence to control the release of the third-order torque reduction instruction, the second-order torque reduction instruction and the first-order torque reduction instruction; after the initialization is completed, the lateral drive anti-skid control is performed, and the release of the torque reduction instruction will cancel the torque reduction instructions of each level of the previous longitudinal working condition in sequence.

8. The EPB-based centralized electric unmanned vehicle anti-skid control system according to claim 6, characterized in that: When the vehicle slips, when the longitudinal drive anti-skid mode is entered, the torque reduction and EPB control instructions of the previous lateral drive anti-skid mode need to be gradually released. That is, after entering the longitudinal drive anti-skid mode from the lateral drive anti-skid mode, if there is no EPB clamping control, the third-order torque reduction instruction, the second-order torque reduction instruction and the first-order torque reduction instruction are directly released in sequence. That is, the longitudinal drive anti-skid control is performed after the initialization is completed. Releasing the torque reduction instruction will cancel the torque reduction instructions of each level of the previous lateral working condition in sequence.

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