An automatic driving anti-skid and anti-slip dual closed-loop cooperative control method and device

Abstract

The application relates to a kind of automatic driving anti-skid, anti-slip dual closed-loop cooperative control method and device, the method includes determining the type of driving road according to real-time driving data and vehicle basic parameters;When the type of driving road is rural non-paved steep slope road, the wheel slip rate and the whole vehicle slip degree are calculated according to real-time driving data and vehicle basic parameters, and the operating condition of the vehicle is determined based on the wheel slip rate and the whole vehicle slip degree;When the operating condition is the coupling condition of skidding and slip slope, the vehicle is controlled by PID closed loop according to the wheel slip rate, the total anti-slip torque is determined according to the updated real-time driving data and vehicle basic parameters, and the vehicle is controlled by outer loop closed loop with the total anti-slip torque as the minimum value of the real-time torque of the motor of the vehicle;The application decouples and identifies two risks of wheel skidding and whole vehicle slip slope, and when in the coupling condition of skidding and slip slope, the vehicle can be controlled by anti-skid and anti-slip dual closed-loop cooperative control, and the safety of the vehicle is improved.

Description

Technical Field

[0001] This invention relates to the field of autonomous driving technology, and in particular to an autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method and device. Background Technology

[0002] Current autonomous driving ramp control strategies are mostly developed based on paved and hardened road surfaces, with a preset stable range of road surface adhesion coefficients. They rely solely on the torque of a single motor to prevent slippage on ramps, without adapting or optimizing for unpaved steep slopes in rural areas. Rural roads present complex conditions such as mud, gravel, potholes, localized mud, and sudden changes in slope. The peak road surface adhesion fluctuates significantly in real time, and the vehicle may simultaneously experience two independent risks during operation: drive wheel slippage and vehicle slippage along the slope.

[0003] Current technologies cannot decouple and identify the risks of wheel slippage and vehicle rollover, making them prone to control logic malfunctions: when starting on a steep slope, wheel slippage and continuous output of drive torque can exacerbate wheel spin and cause vehicle sideslip; during low-speed crawling or temporary parking, insufficient traction makes it difficult to offset the gravitational force of the slope with motor torque alone, creating a risk of rollover; when slippage and rollover occur together, a single braking or torque adjustment method can easily overload the drive motor and cause a large current surge in the power battery, damaging the three-electric system and significantly reducing the safety of autonomous driving. Furthermore, existing solutions lack real-time online identification logic for the coefficient of adhesion on unpaved roads, making it impossible to dynamically adjust the upper limit of torque output and difficult to adapt to the varied road conditions in rural areas.

[0004] Therefore, there is an urgent need to propose a dual closed-loop collaborative control method and device for autonomous driving to prevent slippage and rollback. This would solve the technical problem that existing technologies, when decoupling and identifying the two risks of wheel slippage and vehicle rollback on unpaved steep slopes in rural areas, are prone to control logic mis-triggering, resulting in vehicle sideslip and rollback hazards, which significantly reduce the safety of autonomous driving. Summary of the Invention

[0005] In view of this, it is necessary to provide a dual closed-loop collaborative control method and device for autonomous driving to prevent slippage and rollback, in order to solve the technical problem that when decoupling and identifying the two risks of wheel slippage and vehicle rollback on unpaved steep slopes in rural areas, the control logic is prone to mis-triggered, resulting in the risk of vehicle sideslip and rollback, which greatly reduces the safety of autonomous driving.

[0006] To address the aforementioned problems, in a first aspect, the present invention provides a dual-closed-loop cooperative control method for automatic driving to prevent slippage and runaway, comprising: Acquire real-time driving data and basic vehicle parameters, and determine the road surface type based on the real-time driving data and basic vehicle parameters; When the road surface type is a rural unpaved steep slope road, the wheel slip ratio and the overall vehicle slippage are calculated based on the real-time driving data and the vehicle's basic parameters, and the vehicle's operating conditions are determined based on the wheel slip ratio and the overall vehicle slippage. When the operating condition is a coupled slippage and roll-off condition, the vehicle is subjected to dual closed-loop collaborative control. The dual closed-loop collaborative control is to perform PID closed-loop control on the vehicle based on the wheel slip ratio, and after the PID closed-loop control is completed, the real-time driving data is updated. Based on the updated real-time driving data and the vehicle's basic parameters, the total anti-roll-off torque is determined, and the total anti-roll-off torque is used as the minimum value of the vehicle's motor real-time torque for outer-loop closed-loop control of the vehicle.

[0007] In one possible implementation, determining the road surface type based on the real-time driving data and the vehicle's basic parameters includes: The peak road surface adhesion coefficient is determined based on the real-time driving data and the vehicle's basic parameters. When the peak adhesion coefficient of the road surface is greater than the preset adhesion coefficient threshold, the driving road surface type is determined to be a rural unpaved steep slope road. When the peak adhesion coefficient of the road surface is less than or equal to the preset adhesion coefficient threshold, the road surface type is determined to be other roads.

[0008] In one possible implementation, the real-time driving data includes four-wheel wheel speed signals, vehicle longitudinal acceleration, real-time motor torque, hydraulic braking torque, and slope inclination angle; the basic vehicle parameters include total vehicle mass and wheel rolling radius; the calculation of wheel slip ratio and overall vehicle slippage based on the real-time driving data and the basic vehicle parameters includes: Based on the four wheel speed signals, determine the wheel slip ratio corresponding to each wheel of the vehicle; The longitudinal acceleration of the vehicle body, the real-time torque of the motor, the hydraulic braking torque, the slope inclination angle, the total mass of the vehicle, and the wheel rolling radius are calculated to obtain the pure slope gravity acceleration. The overall vehicle slippage is obtained by dividing the absolute value of the pure slope gravitational acceleration by the product of the gravitational acceleration and the sine of the slope angle.

[0009] In one possible implementation, determining the vehicle's operating conditions based on the wheel slip ratio and the overall vehicle slippage includes: The peak adhesion coefficient of the road surface and the preset benchmark value are calculated to obtain the slippage judgment threshold; The slippage determination threshold is obtained based on the slope angle, the preset slope correction coefficient, and the preset slippage threshold. The vehicle's operating conditions are obtained by comparing the wheel slip ratio with the slippage determination threshold and the overall vehicle slippage with the slippage determination threshold.

[0010] In one possible implementation, comparing the wheel slip ratio with the slippage determination threshold and comparing the overall vehicle slippage with the slippage determination threshold to obtain the vehicle's operating conditions includes: When the wheel slip ratio of all four wheels of the vehicle is less than or equal to the slippage determination threshold and the overall vehicle slippage is less than or equal to the slippage determination threshold, the operating condition is determined to be risk-free normal driving. When the wheel slip ratio of any wheel in the vehicle is greater than the slippage determination threshold and the overall vehicle slippage is less than or equal to the slippage determination threshold, the operating condition is determined to be wheel slippage only. When the wheel slip ratio of all four wheels of the vehicle is less than or equal to the slippage determination threshold and the overall vehicle slippage is greater than the slippage determination threshold, the operating condition is determined to be that only the entire vehicle slips downhill. When the wheel slip ratio of any wheel in the vehicle is greater than the slippage determination threshold and the overall vehicle slippage is greater than the slippage determination threshold, the operating condition is determined to be a slippage and slope-running coupled condition.

[0011] In one possible implementation, the step of performing PID closed-loop control on the vehicle based on the wheel slip ratio includes: Within the current cycle, the slip ratio deviation of each wheel is determined based on the difference between the wheel slip ratio of each wheel and the slip determination threshold. The maximum value of the slip ratio deviation among the four wheels is used as the input of PID closed-loop control to calculate the torque of the vehicle, thereby obtaining the motor drive torque adjustment amount for the current cycle. The target torque is obtained based on the motor drive torque adjustment amount and the real-time torque of the motor; When the target torque is greater than a preset limit threshold, the preset limit threshold is used as the target torque to control the vehicle.

[0012] In one possible implementation, determining the total anti-rollover torque based on the updated real-time driving data and the vehicle's basic parameters includes: The equivalent vehicle speed is determined based on the four wheel speed signals; The slip amount is obtained based on the difference between the equivalent vehicle speed and the longitudinal acceleration of the vehicle body; The residual slip integral correction torque is obtained based on the slip amount; The vehicle weight is obtained based on the total mass of the vehicle and the gravitational acceleration. Based on the total vehicle weight, the wheel rolling radius, and the slope angle, the basic steady-state anti-slip torque is obtained; The sum of the residual slippage integral correction torque and the basic steady-state anti-slippage torque is determined as the total anti-slippage torque.

[0013] In one possible implementation, the method further includes: When the operating condition is that only the wheels slip, the vehicle is subjected to PID closed-loop control based on the wheel slip ratio; When the operating condition is that only the whole vehicle is sliding downhill, the total anti-slip torque is determined, and the total anti-slip torque is used as the minimum value of the real-time torque of the vehicle's motor to perform outer loop closed-loop control on the vehicle. After the PID closed-loop control and / or the outer closed-loop control, the adjusted target driving data is collected. When the target driving data and the vehicle's basic parameters determine that the operating condition is the risk-free normal driving, the dual closed-loop collaborative control of the vehicle is determined to be completed. When the operating condition is determined to be either wheel slippage only / vehicle rollback only / slippage and rollback coupled condition based on the target driving data and the vehicle's basic parameters, the next round of dual closed-loop coordinated control is performed.

[0014] In one possible implementation, the step of using the total anti-rollover torque as the minimum real-time torque of the vehicle's motor for outer-loop closed-loop control includes: During the outer loop closed-loop control process, the real-time torque of the vehicle's motor is monitored, and the real-time torque of the vehicle's motor and the hydraulic braking torque are constrained by the constraint conditions. When the real-time torque of the motor reaches the preset output upper limit value, if the vehicle is still in the condition of vehicle slippage or slippage coupled with the slippage, the hydraulic braking torque of the vehicle is superimposed on the real-time torque of the motor based on the preset gradient.

[0015] Secondly, the present invention also provides an autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control device, comprising: The data acquisition module is used to acquire real-time driving data and basic vehicle parameters, and determine the road surface type based on the real-time driving data and the basic vehicle parameters. The operating condition judgment module is used to calculate the wheel slip ratio and the overall vehicle slippage based on the real-time driving data and the vehicle's basic parameters when the driving road surface type is a rural unpaved steep slope road, and to determine the vehicle's operating condition based on the wheel slip ratio and the overall vehicle slippage. The closed-loop control module is used to perform dual-loop coordinated control of the vehicle when the operating condition is a coupled slippage and roll-off condition. The dual-loop coordinated control is to perform PID closed-loop control on the vehicle based on the wheel slip ratio, and after the PID closed-loop control is completed, update the real-time driving data, determine the total anti-roll-off torque based on the updated real-time driving data and the vehicle's basic parameters, and use the total anti-roll-off torque as the minimum value of the vehicle's motor real-time torque for outer-loop closed-loop control of the vehicle.

[0016] The beneficial effects of this invention are: acquiring real-time driving data and basic vehicle parameters, and determining the road surface type based on the real-time driving data and basic vehicle parameters; when the road surface type is a rural unpaved steep slope road, calculating the wheel slip ratio and overall vehicle slippage based on the real-time driving data and basic vehicle parameters, and determining the vehicle's operating condition based on the wheel slip ratio and overall vehicle slippage; when the operating condition is a coupled slippage and rollover condition, performing dual closed-loop collaborative control on the vehicle; the dual closed-loop collaborative control is PID closed-loop control of the vehicle based on the wheel slip ratio, and in the PI... After the closed-loop control is completed, the real-time driving data is updated. Based on the updated real-time driving data and vehicle basic parameters, the total anti-rollover torque is determined. The total anti-rollover torque is used as the minimum value of the vehicle's motor real-time torque for outer-loop closed-loop control. This invention judges the vehicle's operating condition through vehicle driving data on rural unpaved steep slope roads, thereby decoupling and identifying the two risks of wheel slippage and vehicle rollover. When the vehicle is in a coupled slippage and rollover condition, it can perform dual closed-loop collaborative control for anti-slippage and anti-rollover, improving the safety of autonomous driving. Attached Figure Description

[0017] Figure 1 A schematic flowchart of an embodiment of the dual closed-loop collaborative control method for anti-skid and anti-rollover autonomous driving provided by the present invention; Figure 2 A schematic flowchart illustrating an embodiment of the operating conditions provided by the present invention; Figure 3 For the present invention Figure 1 A schematic flowchart of an embodiment of step S103; Figure 4 This is a schematic diagram of an embodiment of the dual closed-loop collaborative control device for anti-skid and anti-rollover autonomous driving provided by the present invention. Detailed Implementation

[0018] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0019] like Figure 1 As shown, a specific embodiment of the present invention discloses a dual closed-loop cooperative control method for anti-skid and anti-rollover in autonomous driving, comprising: S101. Obtain real-time driving data and basic vehicle parameters, and determine the road surface type based on the real-time driving data and basic vehicle parameters.

[0020] In this embodiment of the invention, real-time driving data of the vehicle is collected through the vehicle's onboard IMU, four-wheel wheel speed sensors, drive motor controller, and brake-by-wire EHB. It also includes acquiring basic vehicle information, such as wheel rolling radius and total vehicle mass. By calculating the real-time driving data and basic vehicle parameters, the current road conditions of the vehicle can be determined based on the calculation results, and the road surface type can be obtained.

[0021] S102. When driving on rural unpaved steep slope roads, calculate the wheel slip ratio and the overall vehicle slippage based on real-time driving data and vehicle basic parameters, and determine the vehicle's operating conditions based on the wheel slip ratio and the overall vehicle slippage.

[0022] In this embodiment of the invention, when the road surface type is a rural unpaved steep slope road, the subsequent processes of this embodiment of the invention are not performed, and the vehicle is controlled in normal mode. When the road surface type is a rural unpaved steep slope road, the subsequent processes can be performed, specifically including calculating the real-time driving data and basic vehicle parameters to obtain the wheel slip ratio and the overall vehicle slippage, so that the wheel slip ratio and the overall vehicle slippage can be judged respectively, and the vehicle's operating condition can be determined based on the judgment results.

[0023] S103. When the operating condition is a combination of slippage and roll-off, the vehicle is subjected to dual closed-loop coordinated control. The dual closed-loop coordinated control is to perform PID closed-loop control on the vehicle based on the wheel slip ratio, and after the PID closed-loop control is completed, the real-time driving data is updated. Based on the updated real-time driving data and the vehicle's basic parameters, the total anti-roll-off torque is determined, and the total anti-roll-off torque is used as the minimum value of the vehicle's motor real-time torque for outer-loop closed-loop control.

[0024] In this embodiment of the invention, when the operating condition is a coupled slippage and roll-off condition, the vehicle is subjected to dual closed-loop collaborative control. Dual closed-loop collaborative control indicates that the vehicle faces the risk of slippage and roll-off, thus requiring anti-slippage and anti-roll-off dual closed-loop collaborative control. Specifically, this includes periodic PID closed-loop control based on the vehicle's wheel slip ratio. After the periodic PID closed-loop control is completed, the vehicle's current real-time driving data is reacquired to obtain the latest real-time driving data. The updated real-time driving data and basic vehicle parameters are used to calculate the total anti-roll-off torque. This total anti-roll-off torque is used as the minimum real-time torque of the vehicle's motor for outer-loop closed-loop control. By first performing periodic PID closed-loop control, and then, after the control is completed, performing outer-loop closed-loop control based on the real-time driving data collected after the control, dual closed-loop collaborative control for anti-slippage and anti-roll-off is achieved.

[0025] The autonomous driving anti-skid and anti-rollover dual closed-loop collaborative control method provided in this invention can be applied to the autonomous driving anti-skid and anti-rollover dual closed-loop collaborative control system. The autonomous driving anti-skid and anti-rollover dual closed-loop collaborative control can be a software system running on a terminal device. The terminal device can be a server, tablet computer, augmented reality (AR) / virtual reality (VR) device, laptop computer, ultra-mobile personal computer (UMPC), netbook, personal digital assistant (PDA), mobile phone, etc. This application embodiment does not impose any restrictions on the specific type of terminal device.

[0026] Compared with existing technologies, this embodiment provides the following: real-time driving data and basic vehicle parameters are acquired, and the road surface type is determined based on these data. When the road surface type is a rural unpaved steep slope, the wheel slip ratio and overall vehicle slippage are calculated based on the real-time driving data and basic vehicle parameters, and the vehicle's operating condition is determined based on these parameters. When the operating condition is a coupled slippage and roll-off condition, dual-closed-loop collaborative control is implemented for the vehicle. This dual-closed-loop collaborative control involves PID closed-loop control of the vehicle based on the wheel slip ratio. After the PID closed-loop control is completed, the real-time driving data is updated. Based on the updated real-time driving data and vehicle basic parameters, the total anti-rollover torque is determined. The total anti-rollover torque is used as the minimum value of the vehicle's motor real-time torque for outer-loop closed-loop control. This invention judges the vehicle's operating condition through vehicle driving data on rural unpaved steep slope roads, thereby decoupling and identifying the two risks of wheel slippage and vehicle rollover. When the vehicle is in a coupled slippage and rollover condition, it can perform dual closed-loop collaborative control for anti-slippage and anti-rollover, improving the safety of autonomous driving.

[0027] In some embodiments of the present invention, step S101 includes: The peak road surface adhesion coefficient is determined based on real-time driving data and basic vehicle parameters.

[0028] In this embodiment of the invention, the real-time driving data includes four-wheel wheel speed signals, vehicle longitudinal acceleration, motor real-time torque, hydraulic braking torque, and slope inclination; the basic vehicle parameters include total vehicle mass and wheel rolling radius; thus, the peak road adhesion coefficient can be determined based on the real-time driving data and the basic vehicle parameters, adapting to the abrupt changes in adhesion characteristics of soil, gravel, and muddy road surfaces, as shown in formula (1): (1) In the formula, For the weight of the whole vehicle, The peak adhesion coefficient of the road surface. For the real-time torque of the motor, For hydraulic braking torque, r The radius of the wheel's rolling motion. The slope angle is denoted by .

[0029] When the peak adhesion coefficient of the road surface is greater than the preset adhesion coefficient threshold, the road surface type is determined to be a rural unpaved steep slope road.

[0030] In this embodiment of the invention, the peak adhesion coefficient of the road surface is judged to determine whether it is greater than a preset adhesion coefficient threshold. If it is, it means that the vehicle is driving on a rural unpaved steep slope road, and it is necessary to monitor and adjust the real-time torque of the vehicle's motor through a dual closed-loop coordinated control method for anti-skid and anti-slip.

[0031] When the peak adhesion coefficient of the road surface is less than or equal to the preset adhesion coefficient threshold, the road surface type is determined to be other roads.

[0032] In this embodiment of the invention, if the peak road surface adhesion coefficient is less than or equal to the preset adhesion coefficient threshold, it means that the vehicle is traveling on a normal road and there is no need to start the anti-skid and anti-slip dual closed-loop collaborative control process of this embodiment of the invention.

[0033] In some embodiments of the present invention, real-time driving data includes four-wheel wheel speed signals, vehicle longitudinal acceleration, real-time motor torque, hydraulic braking torque, and slope inclination angle; basic vehicle parameters include total vehicle mass and wheel rolling radius; step S102 includes: Based on the four wheel speed signals, determine the wheel slip ratio corresponding to each wheel of the vehicle.

[0034] In this embodiment of the invention, the four-wheel speed signal includes the wheel speed signals of the four wheels of the vehicle. The wheel speed signal of each wheel can be calculated separately to obtain the wheel slip ratio corresponding to each wheel of the vehicle. The calculation is shown in formula (2): (2) In the formula, For the first i Wheel slip ratio The first of the four wheel speed signals i Actual wheel speed i =1, 2, 3 indicates 4 wheels. This is the theoretical reference wheel speed for planning vehicle speeds in autonomous driving. This value can be set according to actual conditions.

[0035] The longitudinal acceleration of the vehicle body, the real-time torque of the motor, the hydraulic braking torque, the slope angle, the total mass of the vehicle, and the rolling radius of the wheels are calculated to obtain the pure slope gravity acceleration.

[0036] In this embodiment of the invention, the interference of motor driving force and mechanical braking force on the vehicle body acceleration is removed, and the pure slope gravity acceleration component is extracted. The calculation of vehicle longitudinal acceleration, motor real-time torque, hydraulic braking torque, slope inclination angle, total vehicle mass and wheel rolling radius is used to obtain the pure slope gravity acceleration, as shown in formula (3): (3) In the formula, For pure slope gravitational acceleration, The longitudinal acceleration of the vehicle body was measured. m This refers to the total mass of the vehicle.

[0037] The overall vehicle slippage is obtained by dividing the absolute value of the gravitational acceleration on a pure slope by the product of the gravitational acceleration and the sine of the slope angle.

[0038] In this embodiment of the invention, the gravitational acceleration component of the pure slope is extracted, and the slippage of the whole vehicle is calculated, as shown in formula (4): (4) In the formula, For the overall vehicle slippage, g It is the acceleration due to gravity. The slope angle is denoted by .

[0039] In some embodiments of the present invention, step S102 further includes: The peak adhesion coefficient of the road surface and the preset benchmark value are calculated to obtain the slippage judgment threshold.

[0040] A preset benchmark value is set in this embodiment of the invention. The peak adhesion coefficient of the road surface and the preset benchmark value are calculated as shown in formula (5): (5) In the formula, To determine the slippage threshold, upper and lower limits are set: .

[0041] The slippage determination threshold is obtained based on the slope angle, the preset slope correction coefficient, and the preset slippage threshold.

[0042] In this embodiment of the invention, a preset slip threshold can be set. Preset slope correction coefficient The slope inclination, preset slope correction coefficient, and preset slip threshold are calculated with a value of 0.3, as shown in formula (6): (6) In the formula, The threshold for determining slippage is set, and limitations are imposed. .

[0043] The vehicle's operating conditions are obtained by comparing the wheel slip ratio with the slippage threshold and the overall vehicle slippage with the slippage threshold.

[0044] In this embodiment of the invention, the wheel slip ratio of each wheel is compared with the slip determination threshold to obtain the comparison result of the wheel slip ratio. At the same time, the overall vehicle slip ratio is compared with the slip determination threshold to obtain the corresponding comparison result. The two comparison results are combined and judged to determine the vehicle's operating condition.

[0045] In some embodiments of the present invention, such as Figure 2 As shown, the wheel slip ratio is compared with the slippage threshold, and the overall vehicle slippage is compared with the slippage threshold to obtain the vehicle's operating conditions, including: S201. When the wheel slip ratio of all four wheels of the vehicle is less than or equal to the slippage judgment threshold and the overall vehicle slippage is less than or equal to the slippage judgment threshold, the operating condition is determined to be risk-free normal driving.

[0046] In this embodiment of the invention, the wheel slip ratio of each wheel is judged. When the wheel slip ratio of all four wheels is less than or equal to the slip judgment threshold, it means that there is no risk of slipping. When the overall vehicle slip ratio is less than or equal to the slip judgment threshold, it means that there is no risk of rolling downhill. Based on the judgment of slipping risk and rolling downhill risk, it can be determined that the vehicle's operating condition is risk-free normal driving, and the vehicle is controlled to drive normally.

[0047] S202. When the wheel slip ratio of any wheel in the vehicle is greater than the slippage judgment threshold and the overall vehicle slippage is less than or equal to the slippage judgment threshold, the operating condition is determined to be wheel slippage only.

[0048] In this embodiment of the invention, if the wheel slip ratio of any one of the four wheels of the vehicle is greater than the slippage determination threshold, it indicates that the corresponding wheel is spinning and slipping, and it can be determined that the vehicle is spinning and slipping. If the overall vehicle slippage is less than or equal to the slippage determination threshold, it indicates that the vehicle is not at risk of rolling downhill, and it can be determined that the vehicle only has the risk of slippage, and the vehicle's operating condition is determined to be wheel slippage only.

[0049] S203. When the wheel slip ratio of all four wheels of the vehicle is less than or equal to the slip judgment threshold and the overall vehicle slippage is greater than the slippage judgment threshold, the operating condition is determined to be that only the entire vehicle slips down the slope.

[0050] In this embodiment of the invention, when the wheel slip ratio of all four wheels is less than or equal to the slip determination threshold, it indicates that there is no risk of the vehicle slipping. However, when the overall slip ratio of the vehicle is greater than the slip determination threshold, it indicates that there is a risk of the vehicle slipping downhill. Therefore, it can be determined that the vehicle's operating condition is that only the entire vehicle is slipping downhill.

[0051] S204. When the wheel slip ratio of any wheel in the vehicle is greater than the slippage judgment threshold and the overall vehicle slippage is greater than the slippage judgment threshold, the operating condition is determined to be a slippage and slope coupling condition.

[0052] In this embodiment of the invention, if the wheel slip ratio of any one of the four wheels of the vehicle exceeds the slippage threshold, it indicates that the corresponding wheel is spinning and slipping, thus confirming that the vehicle is experiencing spinning and slipping. Conversely, if the overall vehicle slippage exceeds the slippage threshold, it indicates a risk of rolling backwards, thus determining that the vehicle's operating condition is only rolling backwards. Combining these two factors, the vehicle's operating condition is determined to be a coupled slippage and rolling backwards condition. Based on these two evaluation indicators, four operating conditions are categorized: risk-free normal driving, wheel slippage only, rolling backwards only, and coupled slippage and rolling backwards conditions. Different operating conditions trigger differentiated power braking adjustment strategies.

[0053] In some embodiments of the present invention, step S103 includes: Within the current cycle, the slip ratio deviation of each wheel is determined based on the difference between the wheel slip ratio of each wheel and the slip judgment threshold.

[0054] In this embodiment of the invention, a cycle period can be set. Within the current cycle, the wheel slip ratio and slippage determination threshold can be calculated based on the real-time driving data and basic vehicle parameters collected within the current cycle. The difference between the wheel slip ratio and the slippage determination threshold for each wheel can then be calculated to obtain the slip ratio deviation for each wheel. , Represented as the first k Cycle number i Wheel slip ratio deviation, Represented as the first k The wheel slip ratio of the i-th round of the cycle. The threshold for determining slippage.

[0055] The maximum slip ratio deviation among the four wheels is used as the input to the PID closed-loop control to calculate the vehicle's torque, thus obtaining the motor drive torque adjustment for the current cycle. .

[0056] In this embodiment of the invention, the maximum value of the slip ratio deviation among the four wheels is used as the input of the PID closed-loop control to reduce the driving torque in real time to suppress wheel spin, thereby calculating the vehicle torque as shown in formula (7): (7) In the formula, Represented as the first k The amount of motor drive torque adjustment that needs to be reduced during the control cycle. This is expressed as the PID proportional gain, fast response slip ratio deviation, and a fixed calibration value. This is represented as the PID integral adjustment gain, used to eliminate steady-state slip residual error, with a fixed calibration value. This is represented as PID differential adjustment of gain, which suppresses sudden changes in slip ratio, prevents drastic torque fluctuations, and fixes the calibration value.

[0057] The target torque is obtained based on the motor drive torque adjustment and the real-time torque of the motor.

[0058] In this embodiment of the invention, the motor drive torque adjustment amount is represented as the adjustment amount that needs to be reduced in the current cycle. Therefore, after collecting the real-time motor torque for the current cycle, the motor drive torque adjustment amount is calculated. Then, the target torque can be obtained by subtracting the motor drive torque adjustment amount from the real-time motor torque for the current cycle. This incremental control (changing only a small amount each time) is smoother and can avoid sudden torque changes that could cause vehicle shocks or vibrations. Adjusting only a small amount each cycle, multiple cycles gradually approach the final target.

[0059] When the target torque is greater than the preset limit threshold, the preset limit threshold is used as the target torque to control the vehicle.

[0060] In this embodiment of the invention, during the PID adjustment process, it is also necessary to constrain the target torque. Specifically, a preset limit threshold is set. The preset limit threshold is determined by the maximum output torque of the motor hardware. Thus, the target torque can be constrained by the preset limit threshold. When the target torque is less than or equal to the preset limit threshold, the vehicle can be controlled according to the target torque. If the target torque is greater than the preset limit threshold, the preset limit threshold is used as the target torque to control the vehicle.

[0061] In some embodiments of the present invention, such as Figure 3 As shown, step S103 further includes: S301. Determine the vehicle's equivalent speed based on the four-wheel speed signals.

[0062] In this embodiment of the invention, the average or minimum value of the collected four-wheel speed signals is calculated to obtain the vehicle's equivalent speed.

[0063] S302. The slip amount is obtained based on the difference between the equivalent vehicle speed and the longitudinal acceleration of the vehicle body.

[0064] In this embodiment of the invention, the vehicle speed is estimated by integrating the longitudinal acceleration of the vehicle body over time. The equivalent vehicle speed is then subtracted from this vehicle speed to obtain the slip amount. .

[0065] S303. Obtain the residual slip integral correction torque based on the slip amount.

[0066] In this embodiment of the invention, the slip is integrated and accumulated over time t to obtain the residual slip integral correction torque. As shown in formula (8): (8) In the formula, This is expressed as the residual slip integral correction torque, which compensates for slippage caused by insufficient road surface adhesion. This is represented as the anti-slip integral adjustment gain coefficient, a fixed calibration value.

[0067] S304. The total weight of the vehicle is obtained based on the total mass of the vehicle and the gravitational acceleration.

[0068] Vehicle gravity in the embodiments of the present invention G It can be expressed as the total mass of the vehicle. m Multiplied by gravitational acceleration g ,Right now G=mg .

[0069] S305. Based on the vehicle's weight, wheel rolling radius, and slope angle, the basic steady-state anti-slip torque is obtained.

[0070] In this embodiment of the invention, the vehicle weight, wheel rolling radius, and slope inclination are calculated as shown in formula (9): (9) In the formula, This represents the basic steady-state anti-slip torque required to counteract the component of gravity that causes the slope to slide down.

[0071] S306. The sum of the residual slippage integral correction torque and the basic steady-state anti-slippage torque is determined as the total anti-slippage torque.

[0072] In this embodiment of the invention, the residual slip integral correction torque and the basic steady-state anti-slip torque are calculated as shown in formula (10): (10) In the formula, This represents the total anti-rollback torque used to maintain parking / creep on a ramp.

[0073] In some embodiments of the present invention, the method further includes: When the operating condition is that only the wheels slip, the vehicle is subjected to PID closed-loop control based on the wheel slip ratio.

[0074] In this embodiment of the invention, when the operating condition is that only the wheels slip, indicating that the vehicle's wheels are spinning freely, periodic PID closed-loop control can be performed on the vehicle based on the wheel slip ratio. The PID closed-loop control process is the same as described above and will not be repeated here. In this operating condition, outer-loop closed-loop control is not required; only PID closed-loop control is needed.

[0075] When the operating condition is that only the whole vehicle is sliding downhill, the total anti-slip torque is determined, and the total anti-slip torque is used as the minimum value of the vehicle's motor real-time torque for outer-loop closed-loop control of the vehicle.

[0076] In this embodiment of the invention, when the operating condition is that only the entire vehicle is slipping downhill, it indicates that the vehicle is at risk of slipping downhill. This is the opposite of the condition where only the wheels slip. Under this operating condition, it is only necessary to calculate the total anti-slip torque based on the real-time driving data and the vehicle's basic parameters, and then use the total anti-slip torque as the minimum value of the vehicle's motor real-time torque to perform outer loop closed-loop control on the vehicle. PID closed-loop control is not required. The process of outer loop closed-loop control is the same as the outer loop closed-loop control process described above, and will not be repeated in this invention.

[0077] After PID closed-loop control and / or outer-loop closed-loop control, the target driving data after adjustment is collected. When the operating condition is determined to be risk-free and normal driving based on the target driving data and the vehicle's basic parameters, the dual-loop collaborative control of the vehicle is completed.

[0078] In this embodiment of the invention, after completing the PID closed-loop control and / or outer-loop closed-loop control of the current cycle, the vehicle enters the next cycle and collects real-time driving data again, repeating S101 and subsequent processes. In each cycle, the operating condition is judged. If the operating condition is determined to be risk-free normal driving based on the collected target driving data (i.e., the driving data detected in real time) and the vehicle's basic parameters, it indicates that the vehicle has resumed normal driving, and the dual closed-loop collaborative control of the vehicle can be determined to be completed.

[0079] When the operating condition is determined to be wheel slippage only, vehicle roll only, or a combination of slippage and roll based on the target driving data and vehicle basic parameters, the next round of dual closed-loop coordinated control is initiated.

[0080] In this embodiment of the invention, if the operating condition is determined to be wheel slippage only / vehicle rollback only / slippage and rollback coupled by the target driving data and vehicle basic parameters, then the next round of dual closed-loop collaborative control is performed, and the above process is repeated, thus performing a periodic cycle until the operating condition is determined to be risk-free normal driving by the driving data collected in real time, then the dual closed-loop collaborative control of the vehicle is completed.

[0081] In some embodiments of the present invention, step S103 includes: During the outer loop closed-loop control process, the real-time torque of the vehicle's motor is monitored, and the real-time torque of the vehicle's motor and the hydraulic braking torque are constrained by the constraints. When the real-time torque of the motor reaches the preset output upper limit, if the vehicle is still in the condition of vehicle slippage or slippage coupled with slippage, the hydraulic braking torque of the vehicle is superimposed on the real-time torque of the motor based on the preset gradient.

[0082] In this embodiment of the invention, the real-time torque of the vehicle's motor is monitored during the outer-loop closed-loop control process. This allows for the acquisition of the real-time motor torque, which can then be judged and constrained at each moment. Constraint conditions are set to constrain the vehicle's real-time motor torque and hydraulic braking torque during the control process. The constraint conditions are as follows: 、 Prioritize maintaining the real-time motor torque constant, adjusting only the hydraulic braking torque to ensure the torque combination meets the aforementioned constraint corrections before issuing a torque command. When the real-time motor torque reaches the preset output upper limit, but the vehicle still cannot counteract the slippage trend (i.e., it remains in a vehicle slippage or slippage-slippage coupled condition), a preset gradient can be used to superimpose the vehicle's hydraulic braking torque onto the motor's real-time torque, thereby assisting in locking the vehicle body. The preset gradient can be set according to requirements. The preset gradient is used to gradually "add" the hydraulic braking force to the motor's real-time torque, acting together on the wheels until the vehicle comes to a stop. Specifically, when the operating condition is a slippage-slippage coupled condition, dual closed-loop collaborative control is implemented for the vehicle. Since dual closed-loop collaborative control involves first performing PID closed-loop control and then outer closed-loop control, constraints are applied during the outer closed-loop control. If the operating condition is only wheel slippage, control is applied during the PID closed-loop control; if the operating condition is only vehicle slippage, control is applied during the outer closed-loop control.

[0083] To better implement the autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method in this embodiment of the invention, correspondingly, this embodiment of the invention also provides an autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control device, such as... Figure 4 As shown, the autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control device 400 includes: The data acquisition module 401 is used to acquire real-time driving data and basic vehicle parameters, and determine the road surface type based on the real-time driving data and basic vehicle parameters. The working condition judgment module 402 is used to calculate the wheel slip ratio and the overall vehicle slippage based on real-time driving data and vehicle basic parameters when the driving road surface type is a rural unpaved steep slope road, and to determine the vehicle's operating condition based on the wheel slip ratio and the overall vehicle slippage. The closed-loop control module 403 is used to perform dual closed-loop collaborative control of the vehicle when the operating condition is a coupled slip and roll condition. The dual closed-loop collaborative control is to perform PID closed-loop control of the vehicle based on the wheel slip ratio, and after the PID closed-loop control is completed, update the real-time driving data, determine the total anti-roll torque based on the updated real-time driving data and the vehicle's basic parameters, and use the total anti-roll torque as the minimum value of the vehicle's motor real-time torque to perform outer-loop closed-loop control of the vehicle.

[0084] The autonomous driving anti-skid and anti-rollover dual closed-loop collaborative control device 400 provided in the above embodiments can realize the technical solutions described in the above embodiments of the autonomous driving anti-skid and anti-rollover dual closed-loop collaborative control method. The specific implementation principles of each module or unit can be found in the corresponding content in the above embodiments of the autonomous driving anti-skid and anti-rollover dual closed-loop collaborative control method, which will not be repeated here.

[0085] The above provides a detailed description of the autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method and device provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A dual-closed-loop collaborative control method for anti-skid and anti-rollover in automated driving, characterized in that, include: Acquire real-time driving data and basic vehicle parameters, and determine the road surface type based on the real-time driving data and basic vehicle parameters; When the road surface type is a rural unpaved steep slope road, the wheel slip ratio and the overall vehicle slippage are calculated based on the real-time driving data and the vehicle's basic parameters, and the vehicle's operating conditions are determined based on the wheel slip ratio and the overall vehicle slippage. When the operating condition is a coupled slippage and roll-off condition, the vehicle is subjected to dual closed-loop collaborative control. The dual closed-loop collaborative control is to perform PID closed-loop control on the vehicle based on the wheel slip ratio, and after the PID closed-loop control is completed, the real-time driving data is updated. Based on the updated real-time driving data and the vehicle's basic parameters, the total anti-roll-off torque is determined, and the total anti-roll-off torque is used as the minimum value of the vehicle's motor real-time torque for outer-loop closed-loop control.

2. The autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method according to claim 1, characterized in that, The step of determining the road surface type based on the real-time driving data and the vehicle's basic parameters includes: The peak road surface adhesion coefficient is determined based on the real-time driving data and the vehicle's basic parameters. When the peak adhesion coefficient of the road surface is greater than the preset adhesion coefficient threshold, the driving road surface type is determined to be a rural unpaved steep slope road. When the peak adhesion coefficient of the road surface is less than or equal to the preset adhesion coefficient threshold, the road surface type is determined to be other roads.

3. The autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method according to claim 2, characterized in that, The real-time driving data includes four-wheel wheel speed signals, vehicle longitudinal acceleration, real-time motor torque, hydraulic braking torque, and slope inclination angle; the basic vehicle parameters include total vehicle mass and wheel rolling radius. The step of calculating wheel slip ratio and overall vehicle slippage based on the real-time driving data and the vehicle's basic parameters includes: Based on the four wheel speed signals, determine the wheel slip ratio corresponding to each wheel of the vehicle; The longitudinal acceleration of the vehicle body, the real-time torque of the motor, the hydraulic braking torque, the slope inclination angle, the total mass of the vehicle, and the wheel rolling radius are calculated to obtain the pure slope gravity acceleration. The overall vehicle slippage is obtained by dividing the absolute value of the pure slope gravitational acceleration by the product of the gravitational acceleration and the sine of the slope angle.

4. The autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method according to claim 3, characterized in that, Determining the vehicle's operating conditions based on the wheel slip ratio and the overall vehicle slippage includes: The peak adhesion coefficient of the road surface and the preset benchmark value are calculated to obtain the slippage judgment threshold; The slippage determination threshold is obtained based on the slope angle, the preset slope correction coefficient, and the preset slippage threshold. The vehicle's operating conditions are obtained by comparing the wheel slip ratio with the slippage determination threshold and the overall vehicle slippage with the slippage determination threshold.

5. The autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method according to claim 4, characterized in that, The step of comparing the wheel slip ratio with the slippage determination threshold and comparing the overall vehicle slippage with the slippage determination threshold to obtain the vehicle's operating conditions includes: When the wheel slip ratio of all four wheels of the vehicle is less than or equal to the slippage determination threshold and the overall vehicle slippage is less than or equal to the slippage determination threshold, the operating condition is determined to be risk-free normal driving. When the wheel slip ratio of any wheel in the vehicle is greater than the slippage determination threshold and the overall vehicle slippage is less than or equal to the slippage determination threshold, the operating condition is determined to be wheel slippage only. When the wheel slip ratio of all four wheels of the vehicle is less than or equal to the slippage determination threshold and the overall vehicle slippage is greater than the slippage determination threshold, the operating condition is determined to be that only the entire vehicle slips downhill. When the wheel slip ratio of any wheel in the vehicle is greater than the slippage determination threshold and the overall vehicle slippage is greater than the slippage determination threshold, the operating condition is determined to be a slippage and slope-running coupled condition.

6. The autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method according to claim 4, characterized in that, The step of performing PID closed-loop control on the vehicle based on the wheel slip ratio includes: Within the current cycle, the slip ratio deviation of each wheel is determined based on the difference between the wheel slip ratio of each wheel and the slip determination threshold. The maximum value of the slip ratio deviation among the four wheels is used as the input of PID closed-loop control to calculate the torque of the vehicle, thereby obtaining the motor drive torque adjustment amount for the current cycle. The target torque is obtained based on the motor drive torque adjustment amount and the real-time torque of the motor; When the target torque is greater than a preset limit threshold, the preset limit threshold is used as the target torque to control the vehicle.

7. The autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method according to claim 3, characterized in that, The step of determining the total anti-rollover torque based on the updated real-time driving data and the vehicle's basic parameters includes: The equivalent vehicle speed is determined based on the four wheel speed signals; The slip amount is obtained based on the difference between the equivalent vehicle speed and the longitudinal acceleration of the vehicle body; The residual slip integral correction torque is obtained based on the slip amount; The vehicle weight is obtained based on the total mass of the vehicle and the gravitational acceleration. Based on the total vehicle weight, the wheel rolling radius, and the slope angle, the basic steady-state anti-slip torque is obtained; The sum of the residual slippage integral correction torque and the basic steady-state anti-slippage torque is determined as the total anti-slippage torque.

8. The autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method according to claim 5, characterized in that, The method further includes: When the operating condition is that only the wheels slip, the vehicle is subjected to PID closed-loop control based on the wheel slip ratio; When the operating condition is that only the whole vehicle is sliding downhill, the total anti-slip torque is determined, and the total anti-slip torque is used as the minimum value of the real-time torque of the vehicle's motor to perform outer loop closed-loop control on the vehicle. After the PID closed-loop control and / or the outer closed-loop control, the adjusted target driving data is collected. When the target driving data and the vehicle's basic parameters determine that the operating condition is the risk-free normal driving, the dual closed-loop collaborative control of the vehicle is determined to be completed. When the operating condition is determined to be either wheel slippage only / vehicle rollback only / slippage and rollback coupled condition based on the target driving data and the vehicle's basic parameters, the next round of dual closed-loop coordinated control is performed.

9. The autonomous driving anti-skid and anti-rollover dual closed-loop cooperative control method according to claim 1, characterized in that, The step of using the total anti-rollover torque as the minimum real-time torque of the vehicle's motor to perform outer-loop closed-loop control of the vehicle includes: During the outer loop closed-loop control process, the real-time torque of the vehicle's motor is monitored, and the real-time torque of the vehicle's motor and the hydraulic braking torque are constrained by the constraint conditions. When the real-time torque of the motor reaches the preset output upper limit value, if the vehicle is still in the condition of vehicle slippage or slippage coupled with the slippage, the hydraulic braking torque of the vehicle is superimposed on the real-time torque of the motor based on the preset gradient.

10. An automated driving anti-skid and anti-rollover dual closed-loop cooperative control device, characterized in that, include: The data acquisition module is used to acquire real-time driving data and basic vehicle parameters, and determine the road surface type based on the real-time driving data and the basic vehicle parameters. The operating condition judgment module is used to calculate the wheel slip ratio and the overall vehicle slippage based on the real-time driving data and the vehicle's basic parameters when the driving road surface type is a rural unpaved steep slope road, and to determine the vehicle's operating condition based on the wheel slip ratio and the overall vehicle slippage. The closed-loop control module is used to perform dual-loop coordinated control of the vehicle when the operating condition is a coupled slippage and roll-off condition. The dual-loop coordinated control is to perform PID closed-loop control on the vehicle based on the wheel slip ratio, and after the PID closed-loop control is completed, update the real-time driving data, determine the total anti-roll-off torque based on the updated real-time driving data and the vehicle's basic parameters, and use the total anti-roll-off torque as the minimum value of the vehicle's motor real-time torque for outer-loop closed-loop control of the vehicle.

Images