Control method for rear-drive vehicle to reduce sideslip during deceleration, vehicle controller, medium and equipment

Abstract

The application provides a control method for reducing the side slip of a rear-wheel drive vehicle, comprising: determining the low adhesion state of the rear wheel, adjusting the default value of the rear axle braking ratio to a first rear axle braking ratio, correcting the first rear axle braking ratio according to the current driving condition, determining a second rear axle braking ratio according to the feedback torque and the sliding feedback torque of the rear axle, determining a target rear axle ratio, determining a target hydraulic compensation braking torque according to the target rear axle ratio, and adjusting the hydraulic braking force of the front wheel and the rear wheel according to the target hydraulic compensation braking torque. In this way, the corresponding rear axle braking ratio can be determined according to the slip state of the rear wheel, the feedback force of the rear wheel is reduced to improve the slip state of the rear wheel, and the part of the feedback force of the rear wheel that is reduced is sent to the braking system, the front axle is hydraulically braked and compensated, and then when the rear-wheel drive vehicle is decelerating, the side slip phenomenon caused by the excessive braking force of the rear wheel and the tendency to lock is reduced by adjusting the front-rear braking distribution ratio, and the deceleration stability of the vehicle is improved.

Description

Technical Field

[0001] This application relates to the field of new energy vehicle technology, and in particular to a control method, vehicle controller, medium and equipment for deceleration and sideslip of a rear-wheel drive vehicle. Background Technology

[0002] Rear-wheel drive electric vehicles have an independent rear-drive unit, thus achieving independent rear-wheel drive.

[0003] When road conditions (such as slippery surfaces) are poor, the driver will slow down the vehicle. At this time, the feedback of a rear-wheel drive vehicle is concentrated on the rear wheels. If the braking force on the rear wheels is too great, the rear wheels may lock up and cause sideslip, which seriously affects the deceleration stability of the rear-wheel drive vehicle.

[0004] Therefore, a control method for deceleration and sideslip of rear-wheel drive vehicles is needed to solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the problems existing in the prior art, embodiments of the present invention provide a control method, vehicle controller, medium, and device for deceleration and sideslip of rear-wheel drive vehicles, in order to solve or partially solve the technical problem in the prior art where sideslip easily occurs when decelerating rear-wheel drive vehicles, leading to a decrease in the stability of rear-wheel drive vehicles.

[0006] A first aspect of the present invention provides a method for controlling deceleration and sideslip of a rear-wheel-drive vehicle, the method comprising:

[0007] When the rear wheels are determined to be in a low-traction state, the default value of the vehicle's rear axle braking ratio is adjusted to the first rear axle braking ratio;

[0008] The current driving conditions of the vehicle are obtained, and the braking ratio of the first rear axle is corrected according to the current driving conditions.

[0009] If it is determined that the vehicle chassis is in dynamic handling and stability control mode, the second rear axle braking ratio is determined based on the feedback torque after the rear axle is restricted and the coasting feedback torque, and the minimum value between the second rear axle ratio and the corrected first rear axle ratio is determined as the target rear axle ratio.

[0010] The target hydraulic compensation braking torque is determined based on the target rear axle ratio. If the target hydraulic compensation braking torque is determined to be greater than a preset torque threshold, the hydraulic braking force of the front and rear wheels is adjusted according to the target hydraulic compensation braking torque.

[0011] In the above scheme, determining that the rear wheel is in a low-adhesion state includes:

[0012] Obtain the current speed of the vehicle, and determine the corresponding slip ratio threshold based on the current speed;

[0013] If the rear wheel slip ratio is determined to be greater than the slip ratio threshold, then the rear wheel is determined to be in a low-adhesion state.

[0014] In the above scheme, the step of correcting the braking ratio of the first rear axle according to the current driving conditions includes:

[0015] If the current operating condition is determined to be heavy rain, then continue to maintain the first rear axle braking ratio; or,

[0016] If the current operating condition is determined to be ice and snow, the current ambient temperature is obtained, and the braking ratio of the first rear axle is adjusted according to the current ambient temperature.

[0017] In the above scheme, the step of correcting the braking ratio of the first rear axle according to the current driving conditions includes:

[0018] If the current operating condition is determined to be a long-term low-adhesion condition, the braking ratio of the first rear axle is increased based on the single trigger duration of the low-adhesion state and the number of triggers within the preset duration.

[0019] In the above scheme, the step of correcting the braking ratio of the first rear axle according to the current driving conditions includes:

[0020] If the current operating condition is determined to be a deceleration cornering condition, then the braking ratio of the first rear axle is adjusted according to the vehicle's steering wheel angle and yaw rate; or,

[0021] If the current working condition is determined to be a slope working condition, the braking ratio of the first rear axle is adjusted according to the current slope.

[0022] In the above scheme, determining the target hydraulic compensation braking torque based on the target rear axle ratio includes:

[0023] The first hydraulic compensation braking torque is determined based on the coasting feedback torque and the target rear axle ratio;

[0024] The target hydraulic compensation braking torque is determined based on the coasting feedback torque and the first hydraulic compensation braking torque.

[0025] In the above scheme, adjusting the hydraulic braking force of the front and rear wheels according to the target hydraulic compensation braking torque includes:

[0026] Obtain the distribution ratio of the target hydraulic compensation braking torque;

[0027] The target hydraulic compensation braking torque is distributed to the front and rear wheels according to the specified distribution ratio.

[0028] A second aspect of the present invention provides a vehicle controller, the vehicle controller comprising:

[0029] The first determining unit, when determining that the rear wheel is in a low-adhesion state, adjusts the default value of the vehicle's rear axle braking ratio to the first rear axle braking ratio;

[0030] The correction unit is used to acquire the current driving conditions of the vehicle and correct the braking ratio of the first rear axle according to the current driving conditions.

[0031] The second determining unit, if it determines that the vehicle chassis is in dynamic handling and stability control mode, determines the second rear axle braking ratio based on the feedback torque after the rear axle is restricted and the coasting feedback torque, and determines the minimum value between the second rear axle ratio and the corrected first rear axle ratio as the target rear axle ratio.

[0032] The adjustment unit is used to determine the target hydraulic compensation braking torque based on the target rear axle ratio. If the target hydraulic compensation braking torque is determined to be greater than a preset torque threshold, the hydraulic braking force of the front and rear wheels is adjusted according to the target hydraulic compensation braking torque.

[0033] In the above scheme, the first determining unit is used for:

[0034] Obtain the current speed of the vehicle, and determine the corresponding slip ratio threshold based on the current speed;

[0035] If the rear wheel slip ratio is determined to be greater than the slip ratio threshold, then the rear wheel is determined to be in a low-adhesion state.

[0036] In the above scheme, the correction unit is used for:

[0037] If the current operating condition is determined to be heavy rain, then continue to maintain the first rear axle braking ratio; or,

[0038] If the current operating condition is determined to be ice and snow, the current ambient temperature is obtained, and the braking ratio of the first rear axle is increased according to the current ambient temperature.

[0039] In the above scheme, the correction unit is used for:

[0040] If the current operating condition is determined to be a long-term low-adhesion condition, the braking ratio of the first rear axle is increased based on the single trigger duration of the low-adhesion state and the number of triggers within the preset duration.

[0041] In the above scheme, the correction unit is used for:

[0042] If the current operating condition is determined to be a deceleration cornering condition, then the braking ratio of the first rear axle is adjusted according to the vehicle's steering wheel angle and yaw rate; or,

[0043] If the current working condition is determined to be a slope working condition, the braking ratio of the first rear axle is adjusted according to the current slope.

[0044] In the above scheme, the adjustment unit is used for:

[0045] The first hydraulic compensation braking torque is determined based on the coasting feedback torque and the target rear axle ratio;

[0046] The target hydraulic compensation braking torque is determined based on the coasting feedback torque and the first hydraulic compensation braking torque.

[0047] In the above scheme, the adjustment unit is used for:

[0048] Obtain the distribution ratio of the target hydraulic compensation braking torque;

[0049] The target hydraulic compensation braking torque is distributed to the front and rear wheels according to the specified distribution ratio.

[0050] A third aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of the method described in any of the first aspects.

[0051] A fourth aspect of the present invention provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the steps of the method described in any of the first aspects.

[0052] This invention provides a method, vehicle controller, medium, and device for controlling deceleration and sideslip of a rear-wheel-drive vehicle. The method includes: when the rear wheels are determined to be in a low-traction state, adjusting the default value of the vehicle's rear axle braking ratio to a first rear axle braking ratio; acquiring the vehicle's current driving condition and correcting the first rear axle braking ratio based on the current driving condition; if the vehicle chassis is determined to be in a dynamic handling control mode, determining a second rear axle braking ratio based on the feedback torque after the rear axle is restricted and the coasting feedback torque, and determining the minimum value between the second rear axle ratio and the corrected first rear axle ratio as a target rear axle ratio; and determining the target rear axle ratio based on the... For example, a target hydraulic compensation braking torque is determined. If the target hydraulic compensation braking torque is greater than a preset torque threshold, the hydraulic braking force of the front and rear wheels is adjusted according to the target hydraulic compensation braking torque. In this way, the corresponding rear axle braking ratio can be determined according to the rear wheel slippage state to reduce the feedback force of the rear wheels and improve the rear wheel slippage state. The reduced feedback force of the rear wheels is sent to the braking system, which performs hydraulic braking compensation on the front axle. Thus, when the rear-wheel drive vehicle decelerates, the front and rear brake distribution ratio is adjusted to reduce the phenomenon of sideslip caused by excessive rear wheel braking force tending to lock up, thereby improving the deceleration stability of the rear-wheel drive vehicle. Attached Figure Description

[0053] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0054] In the attached diagram:

[0055] Figure 1 A schematic diagram of the overall structure of a control system for deceleration and sideslip of a rear-wheel drive vehicle according to an embodiment of the present invention is shown.

[0056] Figure 2 A schematic flowchart of a control method for deceleration and sideslip of a rear-wheel drive vehicle according to an embodiment of the present invention is shown;

[0057] Figure 3 A schematic diagram of a vehicle controller structure according to an embodiment of the present invention is shown;

[0058] Figure 4 A schematic diagram of a computer device structure according to an embodiment of the present invention is shown;

[0059] Figure 5 A schematic diagram of a computer-readable storage medium structure according to an embodiment of the present invention is shown. Detailed Implementation

[0060] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0061] To better understand the technical solution of this application, we will first introduce the control system for deceleration and sideslip of rear-wheel drive vehicles. For example... Figure 1 As shown, the control system includes: a gear selector 11, an accelerator pedal sensor 12, a motor controller 13, a chassis brake controller 14, a battery management system (BMS), a rain sensor 15, and a vehicle control unit (VCU); among which,

[0062] The gear selector 11 is used to convert the driver's gear shifting operation into a gear signal and send the gear signal to the vehicle control unit (VCU).

[0063] Accelerator pedal sensor 12 is used to convert the depth of the accelerator pedal into an accelerator opening signal and send the accelerator opening signal to VCU;

[0064] The motor controller 13 is used to receive the motor torque request sent by the VCU, execute the drive according to the motor torque request, and send the actual torque of the motor to the VCU;

[0065] The chassis brake controller 14 is used to provide the VCU with vehicle speed, wheel speed of the front and rear wheels, and vehicle direction of movement; to provide the actual hydraulic braking torque applied to the wheel ends by the chassis (actual hydraulic braking torque of the chassis); and to provide signals such as the driver's steering wheel angle, yaw rate, and slope.

[0066] BMS is used to provide VCU with the battery's allowable discharge power and state of charge (SOC).

[0067] Rainfall sensor 15 is used to send the collected rainfall data to VCU, so that VCU can determine whether the current operating condition is a heavy rain condition based on the rainfall data.

[0068] The VCU is used to calculate the minimum capability (i.e., system feedback capability) of the power system based on the allowable discharge power and SOC, the maximum allowable torque of the motor, and the minimum allowable torque provided by the BMS; calculate the coasting feedback target torque request based on the vehicle speed and throttle opening signal; identify rear wheel slippage based on the wheel speed difference between the front and rear wheels, steering angle, etc., and calculate the rear axle ratio; and feed back the reduced feedback force of the rear wheels to the chassis brake controller for hydraulic braking compensation of the front wheels.

[0069] In other words, VCU is specifically used for:

[0070] When the rear wheels are determined to be in a low-traction state, the default value of the vehicle's rear axle braking ratio is adjusted to the first rear axle braking ratio;

[0071] The current driving conditions of the vehicle are obtained, and the braking ratio of the first rear axle is corrected according to the current driving conditions.

[0072] If it is determined that the vehicle chassis is in dynamic handling and stability control mode, the second rear axle braking ratio is determined based on the feedback torque after the rear axle is restricted and the coasting feedback torque; and the minimum value between the second rear axle ratio and the corrected first rear axle ratio is determined as the target rear axle ratio.

[0073] The target hydraulic compensation braking torque is determined based on the target rear axle ratio. If the target hydraulic compensation braking torque is determined to be greater than a preset torque threshold, the hydraulic braking force of the front and rear wheels is adjusted according to the target hydraulic compensation braking torque.

[0074] The specific implementation strategy for VCU will be explained in detail in the subsequent VCU-side implementation section, so it will not be repeated here.

[0075] Based on the same inventive concept as the foregoing embodiments, this embodiment of the invention also provides a control method for deceleration and sideslip of a rear-wheel-drive vehicle, applied in a VCU, such as... Figure 2 As shown, the method includes the following steps:

[0076] S210, when it is determined that the rear wheel is in a low-adhesion state, the default value of the vehicle's rear axle braking ratio is adjusted to the first rear axle braking ratio.

[0077] As mentioned above, the VCU can obtain the front wheel speed and rear wheel speed from the chassis brake controller, and then determine whether the rear wheel of the vehicle is slipping based on the front and rear wheel speeds.

[0078] In one implementation, determining the rear wheel slip ratio of the vehicle includes:

[0079] Obtain the speed difference between the average speed of the front wheels and the minimum speed of the rear wheels of the vehicle;

[0080] The rear wheel slip ratio is determined based on the absolute value of the speed difference and the average speed of the vehicle's front wheels.

[0081] Specifically, when the vehicle is traveling in a straight line, the VCU can obtain the actual speed of the front wheels and the actual speed of the rear wheels, determine the average speed of the front wheels based on the actual speed of the front wheels, and determine the minimum speed of the rear wheels based on the actual speed of the rear wheels.

[0082] When the vehicle is turning, during the vehicle's movement, the VCU can calculate the reference wheel speeds of the four wheels based on the actual wheel speeds of the four wheels, the steering wheel angle, the vehicle yaw angle, the wheelbase between the left and right wheels, and the wheelbase between the front and rear axles; then, based on the reference wheel speeds of the front wheels, it determines the average speed of the front wheels, and based on the reference wheel speeds of the rear wheels, it determines the minimum speed of the rear wheels.

[0083] Then the rear wheel slip ratio η can be determined according to formula (1):

[0084]

[0085] In formula (1), V1 is the average speed of the front wheels and V2 is the minimum speed of the rear wheels.

[0086] Once the rear wheel slip ratio is determined, it is used to determine whether the rear wheels are in a low-traction state. If so, the default value of the vehicle's rear axle braking ratio is adjusted to the first rear axle braking ratio.

[0087] The default value of the rear axle braking ratio R1 is generally 1. When it is determined that the rear wheel is in a low-adhesion state, R1 will be adjusted to the first rear axle braking ratio R2, which is generally 0.4.

[0088] In one implementation, determining that the rear wheel is in a low-traction state based on the rear wheel slip ratio includes:

[0089] Obtain the vehicle's current speed and determine the corresponding slip ratio threshold based on the current speed;

[0090] If the rear wheel slip ratio is determined to be greater than the slip ratio threshold, then the rear wheel is determined to be in a low-adhesion state.

[0091] It should be noted that the slip ratio threshold can be dynamically adjusted according to the current vehicle speed, allowing the vehicle to better adapt to the current state and dynamically adjust the output torque.

[0092] For example, if the current vehicle speed is ≤10kph, the slip ratio threshold can be set to 30%; if the vehicle speed is greater than or equal to 20kph, the slip ratio threshold can be set to 10%. In this way, when the vehicle starts at low speed or gets out of trouble, the wheels can slip more to output greater torque.

[0093] S211, Obtain the current driving conditions of the vehicle, and correct the braking ratio of the first rear axle according to the current driving conditions.

[0094] In order to improve the accuracy of the rear axle ratio allocation, this embodiment also obtains the current driving conditions of the vehicle and corrects the first rear axle braking ratio according to the current driving conditions to obtain the corrected first rear axle braking ratio.

[0095] In one implementation, the first rear axle braking ratio is corrected according to the current driving conditions to obtain a corrected first rear axle braking ratio, including:

[0096] If the current operating condition is determined to be heavy rain, then continue to maintain the first rear axle braking ratio; or,

[0097] If the current operating condition is determined to be ice and snow, the current ambient temperature is obtained, and the braking ratio of the first rear axle is adjusted according to the current ambient temperature (increasing the braking ratio of the first rear axle).

[0098] Specifically, since the vehicle is equipped with a rain sensor, it is possible to determine whether it is a heavy rain condition based on the rain signal sent by the rain sensor. If it is determined that the current condition is a heavy rain condition, then the rear axle braking ratio will continue to be the first rear axle braking ratio R1.

[0099] If there is a tunnel section in the current road segment, this embodiment will also obtain the distance of the tunnel ahead, adjust the duration of the heavy rain condition based on the tunnel distance, and thereby adjust the duration of the first rear axle braking ratio.

[0100] If the current operating condition is determined to be ice and snow, the first rear axle ratio needs to be gradually increased to the default rear axle braking ratio based on the current ambient temperature.

[0101] If the current temperature is low, such as 0℃, then the growth rate of the first rear axle ratio can be set smaller, such as changing by 1 every 10 seconds (the growth slope is 0.1). For example, if the first rear axle ratio is 0.4 in the first second, then the first rear axle ratio will increase to 0.5 in the second second; and so on, until the first rear axle ratio is increased to 1.

[0102] If the current temperature is high, such as 20℃, then the growth rate of the first rear axle ratio can be set to a large value, such as changing by 1 every 1 second (with a growth slope of 1). For example, if the first rear axle ratio is 0.4 in the first second, then the first rear axle ratio can directly increase to 1 in the second second.

[0103] In another embodiment, the braking ratio of the first rear axle is corrected according to the current driving conditions, including:

[0104] If the current working condition is determined to be a long-term low-adhesion working condition, the braking ratio of the first rear axle is increased according to the single trigger duration of the low-adhesion state or the number of triggers within a preset duration.

[0105] For example, the longer the duration of a single instance of low traction on the vehicle's rear wheels or the more times it is triggered within a preset time period, the smaller the increase slope of the first rear axle braking ratio will be. Conversely, the shorter the duration of a single instance of low traction on the vehicle's rear wheels or the fewer times it is triggered within a preset time period, the larger the increase slope of the first rear axle braking ratio will be.

[0106] For example, if the duration of a single low-adhesion state is 10 seconds, or the number of triggers within 5 seconds is 1, then the growth rate of the first rear axle ratio can be set smaller, such as changing by 1 every 10 seconds (with a growth slope of 0.1). Assuming the first rear axle ratio is 0.4 in the first second, then the first rear axle ratio will increase to 0.5 in the second second; and so on, until the first rear axle ratio is increased to 1.

[0107] For example, if the duration of a single low-adhesion state is 0.2s, or the number of triggers within 5s is 1, then the growth rate of the first rear axle ratio can be set larger, such as changing by 1 every 1s (with a growth slope of 1). For instance, assuming the first rear axle ratio is 0.4 in the first second, then the first rear axle ratio can directly increase to 1 in the second second.

[0108] In another embodiment, the braking ratio of the first rear axle is corrected according to the current driving conditions, including:

[0109] If the current operating condition is determined to be a deceleration cornering condition, then the braking ratio of the first rear axle is adjusted according to the vehicle's steering wheel angle and yaw rate; or,

[0110] If the current working condition is determined to be a slope working condition, the braking ratio of the first rear axle is adjusted according to the current slope.

[0111] Specifically, when the operating condition is deceleration during cornering, the steering wheel angle reflects the driver's desired yaw rate, while the chassis brake controller obtains the actual vehicle yaw rate. The difference between the desired yaw rate and the actual yaw rate indicates whether the vehicle is understeer or oversteer.

[0112] For example, taking left turn as positive, the larger the difference between the expected yaw rate and the actual yaw rate (e.g., greater than the yaw rate threshold), the more understeer the vehicle will be. In this case, more longitudinal force should be applied to the front wheels and the braking ratio of the first rear axle should be reduced.

[0113] Taking left turn as positive, the smaller the difference between the expected yaw rate and the actual yaw rate (e.g., less than or equal to the yaw rate threshold), the more the vehicle is understeering. In this case, more longitudinal force should be applied to the rear wheels to increase the braking ratio of the first rear axle.

[0114] The yaw rate threshold can be determined based on the actual condition of the vehicle and is not restricted here.

[0115] If the current operating condition is a slope condition, a positive slope value represents an uphill slope, and a negative slope value represents a downhill slope. When going downhill, the axle load of the entire vehicle will shift to the front wheels, correspondingly reducing the axle load on the rear wheels. The adhesion provided by the ground will also decrease, so the rear wheel feedback force needs to be reduced. The smaller the slope, the more necessary it is to reduce the braking ratio of the first rear axle.

[0116] This dynamically adjusts the braking ratio of the first rear axle according to different operating conditions, thereby improving the accuracy of the braking ratio of the first rear axle.

[0117] S212, if it is determined that the vehicle chassis is in dynamic handling and stability control mode, then the second rear axle braking ratio is determined based on the feedback torque after the rear axle is restricted and the coasting feedback torque, and the minimum value between the second rear axle ratio and the corrected first rear axle ratio is determined as the target rear axle ratio.

[0118] In this embodiment, the dynamic handling and stability control mode of the vehicle chassis is sometimes active and sometimes off. When the dynamic handling and stability control mode is active, the second rear axle braking ratio is determined based on the feedback torque after the rear axle is restricted and the coasting feedback torque.

[0119] In one embodiment, determining the second rear axle braking ratio based on the feedback torque after rear axle restriction and the coasting feedback torque includes:

[0120] The quotient between the feedback torque after the rear axle is restricted and the coasting feedback torque is determined as the second rear axle braking ratio.

[0121] That is, the braking ratio R3 of the second rear axle can be determined according to formula (2):

[0122]

[0123] Where λ1 is the feedback torque after the rear axle is restricted, and λ2 is the coasting feedback torque.

[0124] In practical applications, when the dynamic handling control mode is activated, the VCU will output a rear axle torque increase request based on the wheel instability. The maximum value of the increased rear axle torque and the coasting feedback torque (negative value) is taken, and this maximum value is the feedback torque after the rear axle is restricted.

[0125] Regarding coasting feedback torque, users can set three feedback levels—weak, medium, and strong—through the central control screen. Each feedback level can be preset with a negative torque request value based on vehicle speed and throttle opening. The negative torque request value is the coasting feedback torque.

[0126] For example, at a vehicle speed of 20 kph, 0% throttle, and strong feedback, the corresponding output coasting feedback torque is -1200 Nm.

[0127] After the second rear axle braking ratio is determined, the minimum value between the second rear axle ratio and the corrected first rear axle ratio is determined as the target rear axle ratio.

[0128] For example, assuming the second rear axle ratio is 0.7 and the corrected first rear axle ratio is 1, then the target rear axle ratio is 0.7.

[0129] S213, determine the target hydraulic compensation braking torque based on the target rear axle ratio. If the target hydraulic compensation braking torque is determined to be greater than a preset torque threshold, adjust the hydraulic braking force of the front and rear wheels based on the target hydraulic compensation braking torque.

[0130] Once the target rear axle ratio is determined, the target hydraulic compensation braking torque is determined based on the target rear axle ratio. If the target hydraulic compensation braking torque is determined to be greater than the preset torque threshold, the hydraulic braking force of the front and rear wheels is adjusted according to the target hydraulic compensation braking torque.

[0131] In one implementation, determining the target hydraulic compensation braking torque based on the target rear axle ratio includes:

[0132] The first hydraulic compensation braking torque is determined based on the coasting feedback torque and the target rear axle ratio;

[0133] The target hydraulic compensation braking torque is determined based on the coasting feedback torque and the first hydraulic compensation braking torque.

[0134] Specifically, the product of the coasting feedback torque and the target rear axle ratio can be determined as the first hydraulic compensation braking torque; then the torque difference between the coasting feedback torque and the first hydraulic compensation braking torque can be determined as the target hydraulic compensation braking torque.

[0135] That is, the target hydraulic compensation braking torque BrkTq can be determined according to formula (3):

[0136] BrkTq=CoastTq×(1-R)(3)

[0137] In formula (3), CoastTq is the coasting feedback torque and R is the target rear axle ratio.

[0138] If the VCU determines that the absolute value of the target hydraulic compensation braking torque is greater than the preset torque threshold, it sends the target hydraulic compensation braking torque to the chassis controller, which then applies appropriate hydraulic braking to the front and rear wheels based on the coasting feedback torque.

[0139] Specifically, the chassis controller typically distributes the target hydraulic compensation braking torque in a ratio of 6.3:3.7 between the front and rear wheels, and then adjusts the hydraulic braking force of each wheel according to the slippage of the front and rear wheels.

[0140] In this way, the corresponding rear axle braking ratio can be determined according to the rear wheel slippage state to reduce the feedback force of the rear wheels and improve the rear wheel slippage state. The reduced feedback force (torque) of the rear wheels is sent to the chassis braking system, which then performs hydraulic braking compensation on the front axle. In turn, when the rear-wheel drive vehicle decelerates, the front and rear brake distribution ratio is adjusted to reduce the phenomenon of sideslip caused by excessive braking force on the rear wheels tending to lock up, thereby improving the deceleration stability of the rear-wheel drive vehicle.

[0141] Based on the same inventive concept as in the foregoing embodiments, this embodiment also provides a vehicle controller, such as... Figure 3 As shown, the vehicle controller includes:

[0142] The first determining unit 31 is used to adjust the default value of the vehicle's rear axle braking ratio to the first rear axle braking ratio when the rear wheel is determined to be in a low-adhesion state based on the rear wheel slip ratio.

[0143] The correction unit 32 is used to obtain the current driving conditions of the vehicle, and correct the first rear axle braking ratio according to the current driving conditions to obtain the corresponding second rear axle braking ratio.

[0144] The second determining unit 33 is used to determine the second rear axle braking ratio based on the feedback torque after the rear axle is restricted and the coasting feedback torque if it is determined that the vehicle chassis is in the dynamic handling and stability control mode; and to determine the minimum value between the second rear axle ratio and the corrected first rear axle ratio as the target rear axle ratio.

[0145] The adjustment unit 34 is used to determine the target hydraulic compensation braking torque according to the target rear axle ratio. If the target hydraulic compensation braking torque is determined to be greater than a preset torque threshold, the hydraulic braking force of the front wheel and the rear wheel is adjusted according to the target hydraulic compensation braking torque.

[0146] Since the apparatus described in the embodiments of this invention is used to implement the method for decelerating and sideslipping a rear-wheel-drive vehicle according to the embodiments of this invention, those skilled in the art can understand the specific structure and variations of the apparatus based on the method described in the embodiments of this invention, and therefore will not be described in detail here. All apparatuses used in the methods of the embodiments of this invention fall within the scope of protection of this invention.

[0147] Based on the same inventive concept, this embodiment provides a computer device 400, such as... Figure 4 As shown, the system includes a memory 410, a processor 420, and a computer program 411 stored in the memory 410 and executable on the processor 420. When the processor 420 executes the computer program 411, it performs the following steps:

[0148] When the rear wheels are determined to be in a low-adhesion state based on the rear wheel slip ratio, the default value of the vehicle's rear axle braking ratio is adjusted to the first rear axle braking ratio.

[0149] The current driving conditions of the vehicle are obtained, and the braking ratio of the first rear axle is corrected according to the current driving conditions.

[0150] If it is determined that the vehicle chassis is in dynamic handling and stability control mode, the second rear axle braking ratio is determined based on the feedback torque after the rear axle is restricted and the coasting feedback torque; and the minimum value between the second rear axle ratio and the corrected first rear axle ratio is determined as the target rear axle ratio.

[0151] The target hydraulic compensation braking torque is determined based on the target rear axle ratio. If the target hydraulic compensation braking torque is determined to be greater than a preset torque threshold, the hydraulic braking force of the front and rear wheels is adjusted according to the target hydraulic compensation braking torque.

[0152] Based on the same inventive concept, this embodiment provides a computer-readable storage medium 500, such as... Figure 5 As shown, a computer program 511 is stored thereon, which, when executed by a processor, performs the following steps:

[0153] When the rear wheels are determined to be in a low-adhesion state based on the rear wheel slip ratio, the default value of the vehicle's rear axle braking ratio is adjusted to the first rear axle braking ratio.

[0154] The current driving conditions of the vehicle are obtained, and the braking ratio of the first rear axle is corrected according to the current driving conditions.

[0155] If it is determined that the vehicle chassis is in dynamic handling and stability control mode, the second rear axle braking ratio is determined based on the feedback torque after the rear axle is restricted and the coasting feedback torque; and the minimum value between the second rear axle ratio and the corrected first rear axle ratio is determined as the target rear axle ratio.

[0156] The target hydraulic compensation braking torque is determined based on the target rear axle ratio. If the target hydraulic compensation braking torque is determined to be greater than a preset torque threshold, the hydraulic braking force of the front and rear wheels is adjusted according to the target hydraulic compensation braking torque.

[0157] Through one or more embodiments of the present invention, the present invention has the following beneficial effects or advantages:

[0158] This invention provides a method, vehicle controller, medium, and device for controlling deceleration and sideslip of a rear-wheel-drive vehicle. The method includes: when the rear wheels are determined to be in a low-traction state based on the rear wheel slip ratio, adjusting the default value of the vehicle's rear axle braking ratio to a first rear axle braking ratio; acquiring the vehicle's current driving condition and correcting the first rear axle braking ratio based on the current driving condition; if it is determined that the vehicle chassis is in a dynamic handling control mode, determining a second rear axle braking ratio based on the feedback torque after the rear axle is restricted and the coasting feedback torque; and determining the minimum value between the second rear axle ratio and the corrected first rear axle ratio as a target rear axle ratio; and according to the target... The rear axle ratio determines the target hydraulic compensation braking torque. If the target hydraulic compensation braking torque is greater than a preset torque threshold, the hydraulic braking force of the front and rear wheels is adjusted according to the target hydraulic compensation braking torque. In this way, the corresponding rear axle braking ratio can be determined according to the rear wheel slippage state to reduce the feedback force of the rear wheels and improve the rear wheel slippage state. The reduced feedback force of the rear wheels is sent to the braking system, which performs hydraulic braking compensation on the front axle. Thus, when the rear-wheel drive vehicle decelerates, the front and rear brake distribution ratio is adjusted to reduce the phenomenon of sideslip caused by excessive rear wheel braking force tending to lock up, thereby improving the deceleration stability of the rear-wheel drive vehicle.

[0159] Furthermore, embodiments of the present invention can adjust the rear axle feedback ratio according to rainfall, ambient temperature, and the duration and frequency of low-adhesion triggering, thereby reducing the rear axle feedback torque in advance to improve the deceleration stability of rear-wheel drive vehicles.

[0160] This invention also considers steering and incline / descent conditions, dynamically adjusting the rear axle feedback ratio to reduce rear axle feedback torque, thereby improving steering and deceleration stability of rear-wheel-drive vehicles and achieving more stable braking performance on slopes. The algorithms and displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used in conjunction with the teachings herein. Based on the above description, the required structure for constructing such systems is readily apparent. Furthermore, this invention is not directed to any particular programming language. It should be understood that the contents of this invention described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of the invention.

[0161] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0162] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0163] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0164] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0165] The various component embodiments of the present invention can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some or all of the components of the gateway, proxy server, or system according to embodiments of the present invention. The present invention can also be implemented as a device or apparatus program (e.g., a computer program and computer program product) for performing some or all of the methods described herein. Such programs implementing the present invention can be stored on a computer-readable medium or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0166] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0167] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0168] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control method of reducing sideslip of a rear-drive vehicle, characterized by, The method comprises: determining that the rear wheel is in a low adhesion state, adjusting a default value of a rear axle braking ratio of the vehicle to a first rear axle braking ratio; obtaining a current driving condition of the vehicle, and correcting the first rear axle braking ratio according to the current driving condition; if it is determined that the chassis of the vehicle is in a dynamic handling control mode, determining a second rear axle braking ratio according to a limited feedback torque of the rear axle and a sliding feedback torque, and determining a minimum value of the second rear axle braking ratio and the corrected first rear axle braking ratio as a target rear axle ratio; determining a target hydraulic compensation braking torque according to the target rear axle ratio, and adjusting hydraulic braking forces of the front wheel and the rear wheel according to the target hydraulic compensation braking torque if it is determined that the target hydraulic compensation braking torque is greater than a preset torque threshold.

2. The method of claim 1, wherein, The determination that the rear wheel is in a low adhesion state comprises: obtaining a current vehicle speed of the vehicle, and determining a corresponding slip rate threshold according to the current vehicle speed; if it is determined that the slip rate of the rear wheel is greater than the slip rate threshold, it is determined that the rear wheel is in a low adhesion state.

3. The method of claim 1, wherein, The correction of the first rear axle braking ratio according to the current driving condition comprises: if it is determined that the current condition is a heavy rain condition, the first rear axle braking ratio is continuously maintained; or if it is determined that the current condition is an ice and snow condition, a current environmental temperature is obtained, and the first rear axle braking ratio is adjusted according to the current environmental temperature.

4. The method of claim 1, wherein, The correction of the first rear axle braking ratio according to the current driving condition comprises: if it is determined that the current condition is a long-term low adhesion condition, the first rear axle braking ratio is increased according to a single triggering duration of the low adhesion state and a triggering frequency within a preset duration.

5. The method of claim 1, wherein, The correction of the first rear axle braking ratio according to the current driving condition comprises: if it is determined that the current condition is a deceleration and cornering condition, the first rear axle braking ratio is adjusted according to a vehicle steering wheel angle and a yaw angular velocity; or if it is determined that the current condition is a slope condition, the first rear axle braking ratio is adjusted according to a current slope.

6. The method of claim 1, wherein, The determination of the target hydraulic compensation braking torque according to the target rear axle ratio comprises: determining a first hydraulic compensation braking torque according to the sliding feedback torque and the target rear axle ratio; determining the target hydraulic compensation braking torque according to the sliding feedback torque and the first hydraulic compensation braking torque.

7. The method of claim 1, wherein, The adjustment of the hydraulic braking forces of the front wheel and the rear wheel according to the target hydraulic compensation braking torque comprises: obtaining a distribution ratio of the target hydraulic compensation braking torque; distributing the corresponding target hydraulic compensation braking torque to the front wheel and the rear wheel according to the distribution ratio.

8. A vehicle control unit, characterized by, The vehicle control unit comprises: a first determination unit configured to determine that the rear wheel is in a low adhesion state, and adjust a default value of a rear axle braking ratio of the vehicle to a first rear axle braking ratio; a correction unit configured to obtain a current driving condition of the vehicle, and correct the first rear axle braking ratio according to the current driving condition; a second determination unit configured to determine a second rear axle braking ratio according to a limited feedback torque of the rear axle and a sliding feedback torque if it is determined that the chassis of the vehicle is in a dynamic handling control mode, and determine a minimum value of the second rear axle braking ratio and the corrected first rear axle braking ratio as a target rear axle ratio; a target hydraulic compensation braking torque determination unit configured to determine a target hydraulic compensation braking torque according to the target rear axle ratio, and adjust hydraulic braking forces of the front wheel and the rear wheel according to the target hydraulic compensation braking torque if it is determined that the target hydraulic compensation braking torque is greater than a preset torque threshold. The second determining unit determines a second rear axle braking ratio according to the limited rear axle feedback torque and the coasting feedback torque if it is determined that the chassis of the vehicle is in the dynamic stability control mode, and determines the minimum value between the second rear axle braking ratio and the corrected first rear axle braking ratio as a target rear axle ratio; The adjusting unit is configured to determine a target hydraulic compensation braking torque according to the target rear axle ratio, and adjust the hydraulic braking force of the front wheels and the rear wheels according to the target hydraulic compensation braking torque if it is determined that the target hydraulic compensation braking torque is greater than a preset torque threshold.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, The program, when executed by a processor, implements the steps of the method of any one of claims 1-7.

10. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor, when executing the program, implements the steps of the method of any one of claims 1-7.

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