Vehicle braking energy recovery and anti-lock cooperative control method and device and vehicle

Abstract

The invention relates to the technical field of vehicles, in particular to a braking energy recovery and anti-lock cooperative control method and device of a vehicle and the vehicle. Predicting the tire slip rate change trend of the current vehicle in a preset time window through a preset slip rate dynamic prediction model to obtain a prediction result; and when the prediction result meets a preset condition, the current vehicle is controlled based on a preset anti-lock pre-activation strategy, and when the anti-lock function of the current vehicle is in an activated state, a target braking energy recovery strategy of the current vehicle is determined, and the current vehicle is controlled. Therefore, the problem that in the background technology, due to energy recovery quit under the low-adhesion road surface condition, tires are temporarily locked is solved, dynamic cooperation of the ABS and an energy recovery system is achieved, smooth transition of braking force is ensured, and the energy recovery efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of vehicles, and particularly relates to a collaborative control method, device and vehicle for braking energy recovery and anti-lock of a vehicle. Background Art

[0002] When braking on a low-adhesion road surface, new energy vehicles usually face conflicts between energy recovery and safety. When the ABS (Anti-lock Braking System) detects that the tire is about to lock, it will forcefully exit energy recovery and switch to hydraulic braking. However, due to the delay in the response of the hydraulic system, the braking force may be interrupted briefly, resulting in an increase in the tire locking time. This will not only cause the vehicle to lose directional stability and get out of control, but also extend the braking distance, seriously threatening driving safety. In addition, the traditional ABS system uses a fixed slip ratio threshold. However, on a low-adhesion road surface, the safe range of the tire slip ratio is significantly reduced, and the fixed threshold is likely to cause premature exit of energy recovery. Moreover, during the activation of the ABS, the energy recovery function is completely disabled, resulting in a loss of recoverable energy of up to 30%, causing energy waste.

[0003] In the related art, the existing technical solutions have certain limitations in solving the above problems. Some solutions solve the problem of braking force interruption through a motor compensation hydraulic delay strategy, but fail to effectively solve the problem of dynamic adjustment of the slip ratio. Other solutions adopt a braking force distribution strategy based on vehicle speed, but when the road surface adhesion coefficient changes suddenly, the robustness of the system is insufficient and it is difficult to adapt to complex road conditions. In addition, some solutions directly cut off energy recovery when the ABS is activated, which will cause obvious fluctuations in the braking force, affecting the smoothness and comfort of braking, and urgent solutions are needed. Summary of the Invention

[0004] The present application provides a collaborative control method, device and vehicle for braking energy recovery and anti-lock of a vehicle to solve the problem of short-term tire locking caused by the exit of energy recovery under low-adhesion road surface conditions. Based on a predictive control collaborative control algorithm, dynamic cooperation between the ABS and the energy recovery system is realized to ensure smooth transition of the braking force and maximize the energy recovery efficiency at the same time.

[0005] The first aspect embodiment of the present application provides a collaborative control method for braking energy recovery and anti-lock of a vehicle, including the following steps:

[0006] Obtain the current driving data of the current vehicle;

[0007] Input the current driving data into a preset slip ratio dynamic prediction model, and predict the change trend of the tire slip ratio of the current vehicle within a preset time window through the preset slip ratio dynamic prediction model to obtain a prediction result;

[0008] When the prediction result meets a preset condition, control the current vehicle based on a preset anti-lock pre-activation strategy, and when the anti-lock function of the current vehicle is in an activated state, determine the target braking energy recovery strategy of the current vehicle, and control the current vehicle based on the target braking energy recovery strategy.

[0009] According to an embodiment of the present application, the prediction result includes a predicted slip ratio and a predicted deceleration. Before controlling the current vehicle based on the preset anti-lock pre-activation strategy, it further includes:

[0010] Judge whether the predicted slip ratio is greater than a preset slip ratio, and whether the change rate of the predicted deceleration is less than a first preset change rate;

[0011] If the predicted slip ratio is greater than the preset slip ratio and the change rate of the predicted deceleration is less than the first preset change rate, it is determined that the prediction result meets the preset condition.

[0012] According to an embodiment of the present application, controlling the vehicle based on the preset anti-lock pre-activation strategy includes:

[0013] Reduce the motor torque of the current vehicle based on a preset decay curve, and increase the hydraulic braking force of the current vehicle based on a preset proportional-integral compensation function.

[0014] According to an embodiment of the present application, determining the target braking energy recovery strategy of the current vehicle and controlling the current vehicle based on the target braking energy recovery strategy includes:

[0015] Obtain the real-time slip ratio of the current vehicle;

[0016] Dynamically adjust the target slip ratio threshold according to the current road adhesion coefficient, and determine the target slip ratio interval according to the target slip ratio threshold;

[0017] If the real-time slip ratio is within the target slip ratio interval, control the energy recovery system of the current vehicle to output negative torque for auxiliary braking based on a preset torque value.

[0018] According to an embodiment of the present application, after controlling the current vehicle based on the target braking energy recovery strategy, it further includes:

[0019] Obtain the current deceleration of the current vehicle;

[0020] Judge whether the change rate of the current deceleration is greater than a second preset change rate;

[0021] If the change rate of the current deceleration is greater than the second preset change rate, the hydraulic compensation gradient is increased based on a preset hydraulic compensation strategy.

[0022] According to an embodiment of the present application, after increasing the hydraulic compensation gradient based on a preset hydraulic compensation strategy, it further includes:

[0023] Re-obtain a new current road surface adhesion coefficient and a new real-time slip ratio;

[0024] Determine whether the new current road surface adhesion coefficient is greater than a preset threshold and whether the new real-time slip ratio is in a preset stable state;

[0025] If the new current road surface adhesion coefficient is greater than the preset threshold and the new real-time slip ratio is in the preset stable state, control the energy recovery system of the current vehicle to output negative torque based on the current braking force demand, and reduce the load of the hydraulic braking system of the current vehicle based on a preset reduction strategy.

[0026] According to the vehicle braking energy recovery and anti-lock braking collaborative control method provided by the embodiments of the present application, the current driving data of the current vehicle is input into a preset slip ratio dynamic prediction model to obtain a prediction result; the current vehicle is controlled based on a preset anti-lock braking pre-activation strategy, and when the anti-lock braking function of the current vehicle is in an activated state, the target braking energy recovery strategy of the current vehicle is determined, and the current vehicle is controlled. Thus, the change trend of the tire slip ratio is predicted by model predictive control and coupled with the braking energy recovery, solving the problem of tire locking during braking on a low-adhesion road surface, realizing the dynamic cooperation between the ABS and the energy recovery system, ensuring the smooth transition of the braking force, and improving the energy recovery efficiency.

[0027] An embodiment of the second aspect of the present application provides a vehicle braking energy recovery and anti-lock braking collaborative control device, including:

[0028] An acquisition module, configured to acquire the current driving data of the current vehicle;

[0029] A prediction module, configured to input the current driving data into a preset slip ratio dynamic prediction model, and predict the change trend of the tire slip ratio of the current vehicle within a preset time window through the preset slip ratio dynamic prediction model to obtain a prediction result;

[0030] A control module, configured to control the current vehicle based on a preset anti-lock braking pre-activation strategy when the prediction result meets a preset condition, and determine the target braking energy recovery strategy of the current vehicle when the anti-lock braking function of the current vehicle is in an activated state, and control the current vehicle based on the target braking energy recovery strategy.

[0031] According to an embodiment of the present application, the prediction result includes a predicted slip ratio and a predicted deceleration. Before controlling the current vehicle based on a preset anti-lock pre-activation strategy, the control module is further configured to:

[0032] Determine whether the predicted slip ratio is greater than a preset slip ratio, and whether the change rate of the predicted deceleration is less than a first preset change rate;

[0033] If the predicted slip ratio is greater than the preset slip ratio and the change rate of the predicted deceleration is less than the first preset change rate, it is determined that the prediction result meets the preset condition.

[0034] According to an embodiment of the present application, the control module is configured to:

[0035] Reduce the motor torque of the current vehicle based on a preset decay curve, and increase the hydraulic braking force of the current vehicle based on a preset proportional-integral compensation function.

[0036] According to an embodiment of the present application, the control module is configured to:

[0037] Obtain the real-time slip ratio of the current vehicle;

[0038] Dynamically adjust the target slip ratio threshold according to the current road surface adhesion coefficient, and determine a target slip ratio interval according to the target slip ratio threshold;

[0039] If the real-time slip ratio is within the target slip ratio interval, control the energy recovery system of the current vehicle to output negative torque for auxiliary braking based on a preset torque value.

[0040] According to an embodiment of the present application, after controlling the current vehicle based on the target braking energy recovery strategy, the control module is further configured to:

[0041] Obtain the current deceleration of the current vehicle;

[0042] Determine whether the change rate of the current deceleration is greater than a second preset change rate;

[0043] If the change rate of the current deceleration is greater than the second preset change rate, increase the hydraulic compensation gradient based on a preset hydraulic compensation strategy.

[0044] According to an embodiment of the present application, after increasing the hydraulic compensation gradient based on a preset hydraulic compensation strategy, the control module is further configured to:

[0045] Re-obtain the new current road surface adhesion coefficient and the new real-time slip ratio;

[0046] Determining whether the new current road surface adhesion coefficient is greater than a preset threshold, and whether the new real-time slip rate is in a preset stable state;

[0047] If the new current road adhesion coefficient is greater than the preset threshold and the new real-time slip rate is in the preset stable state, the energy recovery system of the current vehicle is controlled to output negative torque based on the current braking force demand, and based on the preset reduction strategy, the load of the hydraulic braking system of the current vehicle is reduced.

[0048] According to the vehicle braking energy recovery and anti-lock coordinated control device provided by the embodiment of the present application, the current driving data of the current vehicle is input into the preset slip rate dynamic prediction model to obtain the prediction result; the current vehicle is controlled based on the preset anti-lock pre-activation strategy, and when the anti-lock function of the current vehicle is in the activated state, the target braking energy recovery strategy of the current vehicle is determined, and the current vehicle is controlled. Thus, the problem of the background technology that the tire is temporarily locked due to the exit of energy recovery under low-adhesion road conditions is solved, the dynamic cooperation between ABS and the energy recovery system is realized, the smooth transition of the braking force is ensured, and the energy recovery efficiency is improved.

[0049] The third aspect of the present application provides a vehicle, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the vehicle's brake energy recovery and anti-lock coordinated control method as described in the above embodiment.

[0050] The fourth aspect of the present application provides a computer-readable storage medium, which stores computer instructions, and the computer instructions are used to enable the computer to execute the vehicle braking energy recovery and anti-lock braking coordinated control method as described in the above embodiments.

[0051] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0053] Figure 1 The present invention is a structural diagram of a vehicle's braking energy recovery and anti-lock braking coordinated control system according to an embodiment of the present application;

[0054] Figure 2Flow chart of a method for collaborative control of braking energy recovery and anti-lock braking of a vehicle provided according to an embodiment of the present application;

[0055] Figure 3 Schematic comparison diagram of predictive control and traditional PID control according to an embodiment of the present application;

[0056] Figure 4 Schematic diagram of the braking force migration process according to an embodiment of the present application;

[0057] Figure 5 Schematic diagram of the dynamic slip rate threshold adjustment curve according to an embodiment of the present application;

[0058] Figure 6 Block diagram of a device for collaborative control of braking energy recovery and anti-lock braking of a vehicle according to an embodiment of the present application;

[0059] Figure 7 Schematic diagram of the structure of a vehicle provided according to an embodiment of the present application. Detailed implementation manners

[0060] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application.

[0061] The method, device and vehicle for collaborative control of braking energy recovery and anti-lock braking of a vehicle according to the embodiments of the present application will be described below with reference to the accompanying drawings.

[0062] Before introducing the method for collaborative control of braking energy recovery and anti-lock braking of a vehicle according to the embodiments of the present application, a brief introduction will be given to the braking energy recovery and anti-lock braking collaborative control system of the vehicle involved in the method for collaborative control of braking energy recovery and anti-lock braking of a vehicle of the present application.

[0063] Specifically, the architecture of the braking energy recovery and anti-lock braking collaborative control system of the vehicle according to the embodiments of the present application is as Figure 1 shown, including a sensing layer, a decision-making layer and an execution layer.

[0064] Furthermore, the perception layer includes wheel speed sensors, inertial measurement units (IMU), battery management systems (BMS), and road surface recognition modules (also called road surface adhesion coefficient estimation modules). The inertial measurement unit is used to obtain the current vehicle speed and acceleration, the road surface recognition module is used to calculate the road surface adhesion coefficient μ value in real time based on the Kalman filter, and the battery management system is used to monitor the battery SOC (State Of Charge) and temperature.

[0065] Furthermore, the decision layer includes a dynamic threshold calculator, a predictive control core (also called a predictive controller) and a braking force distributor. Among them, the dynamic threshold calculator is used to adjust the target slip rate threshold according to the real-time road adhesion coefficient μ value. For example, when the real-time road adhesion coefficient μ<0.2, the target slip rate threshold is reduced from 15% to 8%. The predictive control core is used to construct a tire slip rate dynamic model using model predictive control (MPC) to predict the slip rate changes in future time periods (such as within 0.1-0.2s). The braking force distributor is used to migrate the energy recovery torque and hydraulic compensation force according to the gradient.

[0066] Furthermore, the execution layer includes a motor controller, an Electronic Stability Control (ESC) and an Electronic Hydraulic Brake (EHB). The motor controller is used to adjust the energy recovery torque. The ESC is used to correct the instability of the vehicle body. The EHB is used to precisely control the hydraulic pressure.

[0067] The following describes in detail a vehicle's braking energy recovery and anti-lock braking coordinated control method applied to the braking energy recovery and anti-lock braking coordinated control system of the above-mentioned vehicle.

[0068] Specifically, Figure 2 A schematic flow chart of a method for coordinated control of vehicle braking energy recovery and anti-lock braking provided in an embodiment of the present application.

[0069] like Figure 2 As shown, the vehicle's braking energy recovery and anti-lock braking coordinated control method includes the following steps:

[0070] In step S201, the current driving data of the current vehicle is obtained.

[0071] Among them, the current driving data of the current vehicle may include the wheel speed, vehicle speed, brake pedal travel, battery SOC and road adhesion coefficient of the current vehicle.

[0072] Specifically, the embodiments of the present application can obtain the current vehicle's wheel speed through the wheel speed sensor in the vehicle's brake energy recovery and anti-lock braking coordinated control system, can obtain the current vehicle's speed through the inertial measurement unit, can obtain the brake pedal stroke through the opening sensor, can obtain the battery SOC through the battery management system, and can also obtain the road adhesion coefficient through the road surface recognition module, which is not specifically limited here.

[0073] In step S202, the current driving data is input into a preset slip rate dynamic prediction model, and the preset slip rate dynamic prediction model is used to predict the tire slip rate change trend of the current vehicle within a preset time window to obtain a prediction result.

[0074] The preset time window may be a future time window preset by a person skilled in the art, such as within 0.1-0.2 s in the future, which is not specifically limited here.

[0075] Specifically, the vehicle dynamics model (longitudinal braking model) is first established:

[0076]

[0077] Where m is the vehicle mass, a x is the longitudinal acceleration, F x,i is the longitudinal braking force of the i-th wheel, is the air resistance (where C d Drag coefficient, ρ is air density, A is frontal area, v is vehicle speed), F grade =m·g·sin(θ) is the slope resistance, and θ is the road surface angle.

[0078] Individual kinetic equations:

[0079] J ω ·ω ι · =T brake,i -F x,i ·RT fric,i ;

[0080] Among them, J ω is the vehicle moment of inertia, ω i is the angular velocity of the i-th vehicle, T brake,i is the total braking torque, T brake,i =T regen,i +T hydraulic,i , T regen,i Distribute torque to the motor, T hydraulic,i Braking torque, R is the tire radius, T fric,i is the friction torque of the wheel axle.

[0081] Slip ratio definition:

[0082] (Take positive value during braking);

[0083] where λ i is the wheel slip ratio.

[0084] Furthermore, the magic formula tire model is used to calculate the non-linear relationship between the longitudinal tire force F z and the slip ratio λ, which determines the braking force distribution:

[0085] F x λ = D·sin(C·arctan(B·λ - E·(B·λ - arctan(B·λ))));

[0086] where B is the stiffness factor, C is the shape factor, D is the peak factor (D = μ·F z , μ is the road surface adhesion coefficient, F z is the wheel load), and the data of B, C, and D are obtained from actual tests.

[0087] It should be noted that when the road surface adhesion coefficient μ is low, the peak factor D decreases, and the peak of the F x -λ curve shifts to the left, and the slip ratio needs to be limited in the control.

[0088] Model Predictive Control (MPC) formula: Used to dynamically distribute the motor and hydraulic braking torques and judge the future state to avoid problems such as vehicle locking.

[0089] 1) State space model

[0090] x(k + 1) = A·x(k) + B·u(k);

[0091] y(k) = C·x(k);

[0092] where: The state variable x = [ω 1 , ω 2 , ω 3 , ω 4 , v] (four-wheel angular velocity + vehicle speed);

[0093] The control input μ = [T 1regen , T 2hydraulic ;

[0094] The output variable y = [λ 1 , λ 2 , λ 13 , λ 4 .

[0095] 2) Optimization objective function

[0096]

[0097] where λ target is the target slip ratio; both Q and R are weight matrices used to balance slip ratio tracking and control quantity variation, and Δμ(k) is the control quantity variation rate (to prevent torque mutation).

[0098] Furthermore, a slip ratio dynamic prediction model is constructed based on model predictive control (MPC), and current driving data is input into the preset slip ratio dynamic prediction model. The preset slip ratio dynamic prediction model predicts the change trend of the tire slip ratio of the current vehicle within a preset time window to obtain a prediction result.

[0099] Furthermore, in some embodiments, the prediction result includes a predicted slip ratio and a predicted deceleration. Before controlling the current vehicle based on a preset anti-lock pre-activation strategy, it further includes: determining whether the predicted slip ratio is greater than a preset slip ratio and whether the change rate of the predicted deceleration is less than a first preset change rate; if the predicted slip ratio is greater than the preset slip ratio and the change rate of the predicted deceleration is less than the first preset change rate, it is determined that the prediction result meets the preset conditions.

[0100] Wherein, the preset slip ratio can be a slip ratio obtained through computer simulation or a slip ratio set by those skilled in the art according to actual situations, and the first preset change rate can be a change rate obtained through computer simulation or a change rate set by those skilled in the art according to actual situations, and no specific limitation is made here.

[0101] Specifically, MPC performs rolling optimization to predict the future slip ratio of the current vehicle to obtain a predicted slip ratio λ target , and when the predicted slip ratio is greater than the preset slip ratio, it is determined that the prediction result meets the preset conditions.

[0102] For example, when the prediction result meets the following conditions, it can be determined that the prediction result meets the preset conditions:

[0103] Actuator constraint condition: 0 ≤ T tregen ≤ T tregen，max , 0 ≤ T hydraulic ≤ T hydraulic,max ;

[0104] Dynamic constraint condition: T tregen + T hydraulic ≤ μ · F z · R (estimated in real time based on the magic formula).

[0105] In step S203, when the prediction result meets the preset conditions, the current vehicle is controlled based on a preset anti-lock pre-activation strategy. When the anti-lock function of the current vehicle is in the activated state, the target braking energy recovery strategy of the current vehicle is determined, and the current vehicle is controlled based on the target braking energy recovery strategy.

[0106] Further, in some embodiments, controlling the vehicle based on a preset anti-lock pre-activation strategy includes: reducing the motor torque of the current vehicle based on a preset attenuation curve and increasing the hydraulic braking force of the current vehicle based on a preset proportional-integral compensation function.

[0107] Specifically, when the prediction result meets the preset conditions, that is, when it is predicted that the ABS is about to be activated, the braking force smooth transition mechanism is started: the energy recovery torque is reduced according to the gradient, and at the same time, the hydraulic braking force is increased synchronously according to the compensation function to ensure that the total braking torque is constant.

[0108] Further, the motor torque of the current vehicle is reduced based on a preset attenuation curve during the energy recovery exit phase. Exemplarily, the motor torque can be attenuated based on an S-shaped curve to avoid sudden changes:

[0109]

[0110] where t is the total motor torque exit time, t 0 is the start exit time, T 0 is the initial exit torque X, and τ is a set value. τ can take a value of 15 ms, which is not specifically limited here.

[0111] Further, the optimal control quantity output based on MPC is dynamically torque-allocated proportionally:

[0112] T hydraulic =max(T demand -T regen ,0);

[0113] where T demand is the required total torque.

[0114] The pre-judgment ABS activation condition: When the MPC predicts that the slip rate exceeds a certain threshold (such as λ 阈值 >20%) within the next N steps, the torque switching is triggered in advance:

[0115]

[0116] It should be noted that 10 ms in the formula is an example time, and it is subject to the actual motor, which is not specifically limited here.

[0117] Further, the predictive control of the embodiments of the present application is compared with traditional PID control as follows Figure 3 As shown, Figure 3 in the red curve (traditional PID control) fluctuates violently, while the blue curve (MPC predictive control) closely tracks the target slip ratio dotted line. Thus, the MPC of the embodiments of the present application can more accurately track the target slip ratio, reduce overshoot and oscillation, and achieve a more stable control effect.

[0118] Exemplarily, the braking force migration process of the embodiments of the present application can be as follows Figure 4 As shown, Figure 4 in the orange curve is the motor torque, the blue curve is the braking hydraulic pressure, and the black dotted line is the total braking force. From Figure 4 it can be seen that the energy recovery force of the orange curve starts to decay exponentially at 100 ms, the hydraulic pressure of the blue curve increases synchronously, and the total braking force of the black dotted line remains stable. The red area of the traditional scheme is replaced by the green smooth area, indicating that the control strategy of the embodiments of the present application can predict the dynamic changes during braking in advance and achieve a smooth transition of the braking force through a dynamic compensation mechanism.

[0119] Thus, the embodiments of the present application predict the ABS intervention node 80 - 100 ms in advance through MPC, realize a smooth transition of the braking force between the RBS (Regenerative Braking System) and the EHB (transition time < 10 ms), and eliminate the braking force gap.

[0120] Further, in some embodiments, determining the target braking energy recovery strategy of the current vehicle and controlling the current vehicle based on the target braking energy recovery strategy includes: obtaining the real-time slip ratio of the current vehicle; dynamically adjusting the target slip ratio threshold according to the current road surface adhesion coefficient, and determining the target slip ratio interval according to the target slip ratio threshold; if the real-time slip ratio is within the target slip ratio interval, controlling the energy recovery system of the current vehicle to output a negative torque based on a preset torque value for auxiliary braking.

[0121] Specifically, the embodiments of the present application can calculate the real-time slip ratio of the current vehicle through a predictive controller and dynamically adjust the target slip ratio threshold according to the current road surface adhesion coefficient.

[0122] Exemplarily, the process of dynamically adjusting the target slip ratio threshold λ target of the embodiments of the present application with the μ value can adopt the following formula:

[0123]

[0124] Further, during the activation of the ABS, if the real-time slip ratio λ is within the target slip ratio range, the energy recovery system of the current vehicle is controlled to output negative torque for auxiliary braking based on a preset torque value. For example, the motor is allowed to provide 5%-10% negative torque for auxiliary braking, which is not specifically limited herein.

[0125] Among them, the target slip ratio range of the embodiment of the present application is determined by the target slip ratio threshold and can be [λ target -2%, λ target +2%], which is not specifically limited herein.

[0126] Exemplarily, the dynamic slip ratio threshold adjustment curve of the embodiment of the present application can be as shown in Figure 5 wherein, Figure 5 the horizontal axis in is the road surface adhesion coefficient (with a value range of 0.1-0.5), and the vertical axis is the target slip ratio threshold (with a value range of 5%-20%). When the road surface adhesion coefficient is low, the target slip ratio threshold drops steeply, and the safety interval (green shadow) changes dynamically with the target slip ratio threshold.

[0127] Thus, during the activation of the ABS, based on the relationship between the real-time slip ratio and the dynamic threshold, the energy recovery system is allowed to partially intervene within the safety interval, improving the energy recovery rate. In addition, by adjusting the control parameters (such as λtarget, compensation gradient) in real time according to the road surface adhesion coefficient μ value, various working conditions such as ice and snow (such as μ = 0.1) and wet and slippery (such as μ = 0.25) can be covered.

[0128] Further, in some embodiments, after controlling the current vehicle based on the target braking energy recovery strategy, it further includes: obtaining the current deceleration of the current vehicle; determining whether the change rate of the current deceleration is greater than a second preset change rate; if the change rate of the current deceleration is greater than the second preset change rate, then based on a preset hydraulic compensation strategy, increasing the hydraulic compensation gradient.

[0129] Among them, the second preset change rate can be a change rate preset by those skilled in the art, which is not specifically limited herein.

[0130] Specifically, the embodiment of the present application can monitor the deceleration a(t) in real time through an inertial measurement unit and determine whether the change rate of the current deceleration is greater than the second preset change rate. If the change rate of the current deceleration is greater than the second preset change rate, for example, if it is detected that ∣a˙∣>10m / s 3 , then the hydraulic compensation gradient is dynamically increased to suppress the deceleration fluctuation.

[0131] Further, in some embodiments, after increasing the hydraulic compensation gradient based on a preset hydraulic compensation strategy, it also includes: reacquiring a new current road surface adhesion coefficient and a new real-time slip rate; determining whether the new current road surface adhesion coefficient is greater than a preset threshold, and whether the new real-time slip rate is in a preset stable state; if the new current road surface adhesion coefficient is greater than the preset threshold, and the new real-time slip rate is in a preset stable state, controlling the energy recovery system of the current vehicle to output negative torque based on the current braking force demand, and reducing the load of the hydraulic braking system of the current vehicle based on a preset reduction strategy.

[0132] The preset threshold value may be a threshold value preset by a person skilled in the art, such as 0.3, and is not specifically limited here. The preset stable state means that the slip ratio is controlled within a preset safety range.

[0133] Specifically, the embodiment of the present application can obtain the new current road adhesion coefficient in real time through the road recognition module, and calculate the new real-time slip rate through the prediction controller. If the new current road adhesion coefficient is greater than the preset threshold value, and the new real-time slip rate is in a preset stable state, it means that the current vehicle is on a high-adhesion road surface, and the current new real-time slip rate is in a safe range. At this time, the energy recovery re-intervention strategy is started. For example, when the current road adhesion coefficient μ value is restored to above 0.3 and the slip rate is stable, the braking force demand is supplemented by the motor first, and the load of the hydraulic system is reduced, so as to achieve efficient recovery of braking energy while reducing the wear of the brake and extending the life of the brake.

[0134] In order to help those skilled in the art to more clearly and intuitively understand the vehicle braking energy recovery and anti-lock braking coordinated control method in the embodiment of the present application, a specific simulation case is provided below for explanation.

[0135] Specifically, take the current vehicle emergency braking on icy and snowy roads with a road adhesion coefficient of μ=0.15 as an example: when the vehicle is traveling at 60km / h, the IMU detects an abnormal drop in longitudinal acceleration, and the road estimation module outputs μ=0.15. The prediction controller calculates that the real-time slip rate will exceed the target slip rate threshold λ_target=9% after 80ms, triggering ABS pre-activation. At this time, the energy recovery torque decays from 100N·m to 20N·m within 20ms, and the EHB pressure increases linearly from 5MPa to 12MPa.

[0136] Furthermore, when the ABS function is activated, the motor provides a stable negative torque of 10N·m in the range of λ=7%-11%, the hydraulic pressure fluctuation is reduced by 40%, the braking distance is shortened from 28.5m to 25.1m (a reduction of 12%), and the energy recovery is increased from 0Wh to 18Wh.

[0137] A control method for a coordinated braking energy recovery system and an anti-lock braking system of an electric vehicle on a low adhesion road surface (such as an ice and snow or slippery road surface) according to an embodiment of the present application solves the problem of short-term tire lock-up caused by the withdrawal of energy recovery in a traditional system by dynamically integrating the braking force distribution strategies of the ABS and the braking energy recovery system, combining a predictive control model and a real-time compensation mechanism. By monitoring parameters such as wheel speed, slip ratio, and road surface adhesion coefficient in real time, predicting the changing trend of the braking system state, actively adjusting the hydraulic braking force compensation gradient, and optimizing the braking energy recovery efficiency using a dynamic slip ratio threshold, the braking safety and energy recovery rate under a low adhesion road surface are significantly improved.

[0138] Next, a braking energy recovery and anti-lock coordinated control device for a vehicle according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0139] Figure 6 It is a block diagram of a braking energy recovery and anti-lock coordinated control device for a vehicle according to an embodiment of the present application.

[0140] As Figure 6 shown, the braking energy recovery and anti-lock coordinated control device 10 of the vehicle includes: an acquisition module 100, a prediction module 200, and a control module 300.

[0141] Among them, the acquisition module 100 is used to acquire the current driving data of the current vehicle; the prediction module 200 is used to input the current driving data into a preset slip ratio dynamic prediction model, and predict the changing trend of the tire slip ratio of the current vehicle within a preset time window through the preset slip ratio dynamic prediction model to obtain a prediction result; the control module 300 is used to control the current vehicle based on a preset anti-lock pre-activation strategy when the prediction result meets a preset condition, and determine a target braking energy recovery strategy for the current vehicle when the anti-lock function of the current vehicle is in an activated state, and control the current vehicle based on the target braking energy recovery strategy.

[0142] Further, in some embodiments, the prediction result includes a predicted slip ratio and a predicted deceleration. Before controlling the current vehicle based on a preset anti-lock pre-activation strategy, the control module 300 is further used to: determine whether the predicted slip ratio is greater than a preset slip ratio and whether the change rate of the predicted deceleration is less than a first preset change rate; if the predicted slip ratio is greater than the preset slip ratio and the change rate of the predicted deceleration is less than the first preset change rate, it is determined that the prediction result meets the preset condition.

[0143] Further, in some embodiments, the control module 300 is used to: reduce the motor torque of the current vehicle based on a preset decay curve and increase the hydraulic braking force of the current vehicle based on a preset proportional-integral compensation function.

[0144] Further, in some embodiments, the control module 300 is configured to: obtain the real-time slip ratio of the current vehicle; dynamically adjust the target slip ratio threshold according to the current road surface adhesion coefficient, and determine the target slip ratio range according to the target slip ratio threshold; if the real-time slip ratio is within the target slip ratio range, control the energy recovery system of the current vehicle to output negative torque based on a preset torque value for auxiliary braking.

[0145] Further, in some embodiments, after controlling the current vehicle based on the target braking energy recovery strategy, the control module 300 is further configured to: obtain the current deceleration of the current vehicle; determine whether the change rate of the current deceleration is greater than a second preset change rate; if the change rate of the current deceleration is greater than the second preset change rate, increase the hydraulic compensation gradient based on a preset hydraulic compensation strategy.

[0146] Further, in some embodiments, after increasing the hydraulic compensation gradient based on a preset hydraulic compensation strategy, the control module 300 is further configured to: re-obtain the new current road surface adhesion coefficient and the new real-time slip ratio; determine whether the new current road surface adhesion coefficient is greater than a preset threshold and whether the new real-time slip ratio is in a preset stable state; if the new current road surface adhesion coefficient is greater than the preset threshold and the new real-time slip ratio is in the preset stable state, control the energy recovery system of the current vehicle to output negative torque based on the current braking force demand, and reduce the load of the hydraulic braking system of the current vehicle based on a preset reduction strategy.

[0147] It should be noted that the foregoing explanation of the embodiments of the braking energy recovery and anti-lock collaborative control method for a vehicle also applies to the braking energy recovery and anti-lock collaborative control device for the vehicle in this embodiment, and will not be elaborated here.

[0148] According to the braking energy recovery and anti-lock collaborative control device for a vehicle provided by an embodiment of the present application, the current driving data of the current vehicle is input into a preset slip ratio dynamic prediction model to obtain a prediction result; the current vehicle is controlled based on a preset anti-lock pre-activation strategy, and when the anti-lock function of the current vehicle is in an activated state, the target braking energy recovery strategy of the current vehicle is determined and the current vehicle is controlled. Thereby, the problem that the tires are briefly locked due to the withdrawal of energy recovery under low adhesion road surface conditions in the background art is solved, the dynamic cooperation between the ABS and the energy recovery system is realized, the smooth transition of the braking force is ensured, and the energy recovery efficiency is improved.

[0149] Figure 7 It is a schematic structural diagram of a vehicle provided by an embodiment of the present application. The vehicle may include:

[0150] A memory 701, a processor 702, and a computer program stored on the memory 701 and executable on the processor 702.

[0151] When the processor 702 executes the program, it implements the braking energy recovery and anti-lock collaborative control method of the vehicle provided in the above embodiments.

[0152] Furthermore, the vehicle further includes:

[0153] A communication interface 703 for communication between the memory 701 and the processor 702.

[0154] The memory 701 is used to store a computer program executable on the processor 702.

[0155] The memory 701 may include a high-speed RAM memory, and may also include non-volatile memory, such as at least one disk memory.

[0156] If the memory 701, the processor 702, and the communication interface 703 are implemented independently, the communication interface 703, the memory 701, and the processor 702 can be interconnected through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, Figure 7 only a thick line is used to represent it in the figure, but it does not mean that there is only one bus or one type of bus.

[0157] Optionally, in a specific implementation, if the memory 701, the processor 702, and the communication interface 703 are integrated on a chip, the memory 701, the processor 702, and the communication interface 703 can communicate with each other through an internal interface.

[0158] The processor 702 may be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0159] The embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the above-mentioned cooperative control method for braking energy recovery and anti-lock of a vehicle.

[0160] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or N embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0161] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0162] Any process or method description shown in the flowchart or described in other ways herein can be understood as representing a module, segment, or part of code including one or more executable instructions for implementing a customized logic function or process. The scope of the preferred embodiments of the present application includes additional implementations, where the functions may be executed in a substantially simultaneous manner or in a reverse order according to the involved functions, rather than in the order shown or discussed, which should be understood by those skilled in the art of the embodiments of the present application.

[0163] The logic and / or steps represented in the flowchart or otherwise described herein can, for example, be considered as a definable sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or used in conjunction with these instruction execution systems, apparatus, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion (electronic device) having one or N wirings, a portable computer disk cartridge (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0164] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having suitable combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0165] Those of ordinary skill in the art of this technology can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments.

[0166] In addition, each functional unit in various embodiments of the present application may be integrated into one processing module, or each unit may exist physically alone, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0167] The above-mentioned storage medium may be a read-only memory, a magnetic disk, an optical disc, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A vehicle braking energy recovery and anti-lock braking coordinated control method, characterized in that: The following steps are involved: Get the current driving data of the current vehicle; Inputting the current driving data into a preset slip rate dynamic prediction model, predicting the tire slip rate change trend of the current vehicle within a preset time window through the preset slip rate dynamic prediction model, and obtaining a prediction result; When the prediction result meets the preset conditions, the current vehicle is controlled based on the preset anti-lock braking pre-activation strategy, and when the anti-lock braking function of the current vehicle is in an activated state, the target braking energy recovery strategy of the current vehicle is determined, and the current vehicle is controlled based on the target braking energy recovery strategy.

2. The method according to claim 1, characterized in that The prediction result includes a predicted slip rate and a predicted deceleration. Before the current vehicle is controlled based on a preset anti-lock braking pre-activation strategy, the method further includes: determining whether the predicted slip ratio is greater than a preset slip ratio, and whether a change rate of the predicted deceleration is less than a first preset change rate; If the predicted slip ratio is greater than the preset slip ratio, and the change rate of the predicted deceleration is less than the first preset change rate, it is determined that the prediction result meets the preset condition.

3. The method according to claim 1, characterized in that The controlling the vehicle based on a preset anti-lock braking pre-activation strategy includes: The motor torque of the current vehicle is reduced based on a preset decay curve, and the hydraulic braking force of the current vehicle is increased based on a preset proportional-integral compensation function.

4. The method according to claim 1, characterized in that: The determining a target braking energy recovery strategy for the current vehicle and controlling the current vehicle based on the target braking energy recovery strategy includes: Get the real-time slip rate of the current vehicle; dynamically adjusting a target slip rate threshold according to the current road surface adhesion coefficient, and determining a target slip rate range according to the target slip rate threshold; If the real-time slip ratio is within the target slip ratio range, the energy recovery system of the current vehicle is controlled to output a negative torque based on a preset torque value to perform auxiliary braking.

5. The method according to claim 1, characterized in that After the current vehicle is controlled based on the target braking energy recovery strategy, the method further includes: Get the current deceleration of the current vehicle; Determining whether the change rate of the current deceleration is greater than a second preset change rate; If the change rate of the current deceleration is greater than the second preset change rate, the hydraulic compensation gradient is increased based on a preset hydraulic compensation strategy.

6. The method according to claim 1, characterized in that After increasing the hydraulic compensation gradient based on the preset hydraulic compensation strategy and increasing the hydraulic compensation gradient based on the preset hydraulic compensation strategy, the method further includes: Re-obtain a new current road adhesion coefficient and a new real-time slip rate; Determining whether the new current road surface adhesion coefficient is greater than a preset threshold, and whether the new real-time slip rate is in a preset stable state; If the new current road adhesion coefficient is greater than the preset threshold and the new real-time slip rate is in the preset stable state, the energy recovery system of the current vehicle is controlled to output negative torque based on the current braking force demand, and based on the preset reduction strategy, the load of the hydraulic braking system of the current vehicle is reduced.

7. A vehicle braking energy recovery and anti-lock braking coordinated control device, characterized in that: include: An acquisition module is used to acquire the current driving data of the current vehicle; A prediction module, used for inputting the current driving data into a preset slip rate dynamic prediction model, predicting the tire slip rate change trend of the current vehicle within a preset time window through the preset slip rate dynamic prediction model, and obtaining a prediction result; A control module is used to control the current vehicle based on a preset anti-lock braking pre-activation strategy when the prediction result meets the preset conditions, and to determine a target braking energy recovery strategy for the current vehicle when the anti-lock braking function of the current vehicle is in an activated state, and to control the current vehicle based on the target braking energy recovery strategy.

8. The device according to claim 7, characterized in that The prediction result includes a predicted slip rate and a predicted deceleration. Before controlling the current vehicle based on the preset anti-lock braking pre-activation strategy, the control module is further used to: determining whether the predicted slip ratio is greater than a preset slip ratio, and whether a change rate of the predicted deceleration is less than a first preset change rate; If the predicted slip ratio is greater than the preset slip ratio, and the change rate of the predicted deceleration is less than the first preset change rate, it is determined that the prediction result meets the preset condition.

9. A vehicle, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the vehicle's brake energy recovery and anti-lock coordinated control method as described in any one of claims 1 to 6.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer program is executed by a processor to implement the vehicle's brake energy recovery and anti-lock braking coordinated control method as described in any one of claims 1 to 6.

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