Braking control method for dual-voltage vehicle

Abstract

The application relates to a brake control method of a dual-source power vehicle. The method comprises the following steps: determining a risk index of the dual-source power vehicle under a current working condition according to vehicle parameters of the dual-source power vehicle and environment parameters of a current environment; calculating an upper limit of a vehicle speed of the dual-source power vehicle under the current working condition based on the risk index; calculating a first deceleration according to a brake pedal opening degree of the dual-source power vehicle and a current vehicle speed, and calculating a second deceleration according to the current vehicle speed and the upper limit of the vehicle speed; calculating a total brake force required by the dual-source power vehicle for deceleration based on a maximum value in the first deceleration and the second deceleration; and performing brake control on the dual-source power vehicle by the total brake force when the current vehicle speed of the dual-source power vehicle reaches the upper limit of the vehicle speed and the risk index is higher than a risk threshold. The method can improve brake safety.

Description

Technical Field

[0001] This application relates to the field of vehicle braking technology, and in particular to a braking control method for a dual-powered vehicle. Background Technology

[0002] With the expansion of the application of dual-powered vehicles, their usage frequency in complex scenarios such as mountain highways, mining transportation, and plateau construction has significantly increased. However, in these complex scenarios, the risks of prolonged downhill braking, brake fade under heavy loads, slippage and instability on low-adhesion surfaces, and collisions in low visibility conditions are more prominent, making traditional safety braking methods insufficient to meet safety requirements.

[0003] Currently, existing technologies primarily rely on vehicle speed, road gradient, and fixed speed limits for braking control. However, this approach suffers from low braking safety. For example, patent application CN118953361A determines whether a vehicle is speeding based solely on a fixed warning limit and applies braking control only when speeding occurs, which also results in low braking safety. Summary of the Invention

[0004] Therefore, it is necessary to provide a braking control method for dual-powered vehicles that can improve braking safety, addressing the aforementioned technical problems.

[0005] A braking control method for a dual-powered vehicle, the method comprising:

[0006] S1. Determine the risk index of the dual-source power supply vehicle under the current operating conditions based on the vehicle parameters and the environmental parameters of the current environment.

[0007] Preferably, the environmental parameters include, but are not limited to, the road surface condition, road surface temperature, rainfall / snowfall intensity, camera visibility distance, fog / rain / snow / dust type, altitude, ambient temperature, wind speed, wind direction, and road surface adhesion coefficient of the dual-powered vehicle.

[0008] Preferably, the vehicle parameters include, but are not limited to, wheel speed, drive wheel circumference speed, brake pedal opening, ABS / ESC / ASR / EBS intervention status, longitudinal acceleration, attitude, current vehicle speed, intake pressure / ambient pressure, cooling system operating status, power demand, vehicle driving direction, yaw rate, lateral acceleration, and steering wheel angle for dual-powered vehicles.

[0009] Preferably, the risk index includes, but is not limited to, a longitudinal risk index that measures the risk of a vehicle in the direction of travel, a lateral risk index that measures the risk of a vehicle in the left and right directions, and a visibility risk index that measures the degree of limitation of a vehicle's environmental perception ability.

[0010] S2. Based on the risk index, calculate the maximum speed of the dual-source power supply vehicle under the current operating conditions;

[0011] S3. Calculate the first deceleration based on the brake pedal opening and the current vehicle speed of the dual-powered vehicle, and calculate the second deceleration based on the current vehicle speed and the upper limit of vehicle speed.

[0012] Preferably, the calculation process for the first deceleration and the second deceleration includes: through The first deceleration a is obtained ped ,pass The second deceleration a is obtained spd f ped To represent the lookup of the brake pedal opening P using the pedal opening-deceleration mapping table bark The first deceleration k that matches the current vehicle speed v p k is the proportionality coefficient. i v is the integral coefficient, t is time, and v max This refers to the maximum speed limit for vehicles.

[0013] S4. Calculate the total braking force required for the dual-source power supply vehicle to decelerate based on the maximum value of the first deceleration and the second deceleration;

[0014] Preferably, the total braking force F brk,req The calculation formula is m is the mass of the dual-source powered vehicle. , F roll F is the rolling resistance parameter. aero For wind resistance parameters, C rr The rolling resistance coefficient, C is the density of air. d Where A is the drag coefficient and A is the frontal area.

[0015] S5. When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, the dual-powered vehicle is braked by the total braking force.

[0016] In one embodiment, step S5 includes:

[0017] Based on the distances between the center of mass of the dual-powered vehicle and the front and rear axles of the dual-powered vehicle, the normal loads of the front and rear axles are calculated.

[0018] Based on the front axle normal load and the road adhesion coefficient of the current driving surface, calculate the maximum available braking force of the front axle; based on the rear axle normal load and the road adhesion coefficient, calculate the maximum available braking force of the rear axle.

[0019] Based on the aforementioned front axle normal load F z,f and the rear axle normal load F z,r Through formula Calculate the first front axle distribution ratio ;

[0020] Based on the total braking force F brk,rep and the first front axle allocation ratio ,pass and Calculate the first candidate braking force allocated to the front axle from the total braking force. and the second candidate braking force allocated to the rear axle ;

[0021] The minimum value between the first candidate braking force and the maximum available braking force of the front axle is determined as the first front axle braking force to be allocated to the front axle; the total braking force minus the first front axle braking force is calculated; the minimum value between the subtraction result and the maximum available braking force of the rear axle is determined as the first rear axle braking force to be allocated to the rear axle.

[0022] When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on the first front axle braking force and the first rear axle braking force.

[0023] Preferably, the front axle normal load F z,f The calculation formula is Rear axle normal load F z,r The calculation formula is m is the mass, a is the distance from the center of mass to the front axis, b is the distance from the center of mass to the rear axis, L = a + b, and h is the height of the center of mass above the ground.

[0024] Preferably, the maximum available braking force of the front axle refers to the maximum effective force that the front axle can provide during braking to decelerate a dual-powered vehicle; the maximum available braking force of the rear axle refers to the maximum effective force that the rear axle can provide during braking to decelerate a dual-powered vehicle; the maximum available braking force of the front axle... The calculation formula is Maximum available braking force of the rear axle The calculation formula is .

[0025] In one embodiment, the method further includes:

[0026] If based on the first front axle braking force F x,f1 and the first rear axle braking force Fx,r1 When braking control is applied to the dual-powered vehicle, if the vehicle speed cannot be reduced to the recommended speed range or the dual-powered vehicle cannot drive stably, then... Calculate the second front axle distribution ratio ;

[0027] Based on the second front axle distribution ratio, calculate the second front axle braking force distributed to the front axle and the second rear axle braking force distributed to the rear axle in the total braking force;

[0028] When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on the second front axle braking force and the second rear axle braking force.

[0029] In one embodiment, step S5 includes:

[0030] Based on the vehicle parameters, the state parameters of the motor in the dual-source power supply vehicle, and the road surface adhesion coefficient of the current driving surface, the upper limit of the regenerative braking force of the motor is determined; based on the risk index and the state parameters of the motor, the target regenerative ratio is determined.

[0031] Based on the upper limit of regenerative braking force and the target regenerative ratio, determine the motor power required to be provided by the motor and the mechanical braking force required to be provided by the mechanical braking device in the dual-source power supply vehicle in the total braking force.

[0032] When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on the electric motor force and the mechanical braking force.

[0033] In one embodiment, the calculation process for the upper limit of the regenerative braking force includes:

[0034] The upper limit of the regenerative torque of the motor is determined based on the current temperature and current speed of the motor, the system status of the dual-source power supply vehicle, and the DC circuit voltage between the motor and the battery of the dual-source power supply vehicle.

[0035] Based on the upper limit of regenerative torque The wheel radius R of the dual-source power supply vehicle w Transmission efficiency The overall speed ratio i is obtained through... Calculate the upper limit F of the wheel axial force of the dual-source powered vehicle. m,lim Determine the upper limit of the maximum regenerative braking force, the upper limit of the available longitudinal force for drive shaft attachment, and the upper limit of the global safety limiting force for the dual-source power supply vehicle.

[0036] The minimum value among the upper limit of the wheel axial force, the upper limit of the maximum regenerative braking force, the upper limit of the available longitudinal force for drive shaft attachment, and the upper limit of the global safety limiting force is determined as the upper limit of the regenerative braking force.

[0037] In one embodiment, the calculation process for the target regeneration ratio includes:

[0038] Based on the battery status of the dual-powered vehicle, its connection status with the external power grid, and the downhill slope index in the risk indicators of the dual-powered vehicle, an initial proportion is determined; based on the maximum value R in the risk index, through... Determine the correction factor f for the initial proportion risk ; f is the first preset value. min f is the preset lower cutoff limit. max `clip` is the preset upper limit for truncation; `clip` is the truncation function.

[0039] When the total braking force is greater than the second preset value, the ratio of the upper limit of the regenerative braking force to the total braking force is determined as the first candidate percentage; the product of the initial percentage and the correction coefficient is determined as the second candidate percentage.

[0040] The minimum value between the first candidate percentage and the second candidate percentage is determined as the target regeneration percentage.

[0041] In one embodiment, the method further includes:

[0042] Based on the electric motor power And the current vehicle speed v, through Calculate the first candidate regeneration power The minimum value among the upper limit of motor regenerative power, upper limit of absorption capacity, upper limit of DC bus voltage constraint power, upper limit of stability power constraint power and preset safety upper limit is the second candidate regenerative power.

[0043] The minimum value between the candidate regenerative power and the second candidate regenerative power is determined as the desired regenerative power of the motor, so as to perform braking control based on the desired regenerative power.

[0044] In one embodiment, the calculation process of the longitudinal risk index in the risk index in step S1 includes:

[0045] Based on the maximum permissible deceleration of the dual-powered vehicle on the current road surface. The acceleration a caused by the slope grade and the expected deceleration a req1 ,pass Calculate the deceleration margin of the dual-powered vehicle; based on the deceleration margin Mdec ,pass Obtain the deceleration margin sub-risk r dec risk is a mapping function;

[0046] Based on the current vehicle speed v and the preset safe vehicle speed v of the dual-source power supply vehicle safe ,pass Obtaining the risk of hypervelocities r spd ;

[0047] Based on the current temperature T of the braking system of the dual-powered vehicle b and temperature threshold T warn ,pass Obtaining thermal decay risk r heat ;

[0048] Based on the weighted summation of the deceleration margin sub-risk, the overspeed sub-risk, and the thermal decay sub-risk, the longitudinal risk index in the risk index is determined, and the vehicle speed limit is calculated using the longitudinal risk index.

[0049] In one embodiment, calculating the vehicle speed limit using the longitudinal risk index includes:

[0050] Obtain the reference speed limit of the current driving road surface;

[0051] Based on the aforementioned benchmark speed limit v base and the longitudinal risk index R v ,pass The maximum speed v of the dual-source powered vehicle under the current operating conditions is obtained. max K v These are calibration coefficients.

[0052] In one embodiment, step S5 includes:

[0053] Obtain the preset speed margin and the lower limit of the recommended speed range for the dual-source powered vehicle on the current road surface;

[0054] The result of subtracting the speed margin from the upper limit of vehicle speed is determined as the upper limit of the recommended vehicle speed range;

[0055] When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, the total braking force is used to brake the dual-powered vehicle so that the speed of the dual-powered vehicle is within the recommended speed range.

[0056] The aforementioned braking control method for dual-powered vehicles determines the risk index of the dual-powered vehicle under the current operating conditions based on the vehicle parameters and environmental parameters of the current environment. Based on the risk index, the upper speed limit of the dual-powered vehicle under the current operating conditions is calculated. This allows for dynamic adjustment of the upper speed limit. Consequently, when calculating the second deceleration based on the current speed and the upper speed limit, a second deceleration suitable for the current operating conditions is obtained. Therefore, when calculating the total braking force required for deceleration of the dual-powered vehicle based on the maximum value of the first and second decelerations, the calculated total braking force ensures that the dual-powered vehicle can safely travel on the road, improving braking safety. Attached Figure Description

[0057] Figure 1 This is a flowchart illustrating a braking control method for a dual-powered vehicle in one embodiment.

[0058] Figure 2 This is a structural block diagram of the environment perception module in one embodiment;

[0059] Figure 3 This is a schematic diagram of the overall structure of the control system in one embodiment;

[0060] Figure 4 This is an overall flowchart of a safety assurance control method under extreme operating conditions in one embodiment;

[0061] Figure 5 This is a flowchart of braking energy recovery in one embodiment. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0063] In one embodiment, a control system is provided for executing a braking control method for a dual-powered vehicle. The dual-powered vehicle includes a first electrical subsystem, a second electrical subsystem, a motor, a braking system, a steering system, millimeter-wave radar, a camera, a road surface adhesion sensor, and a weather sensor. Both the first and second electrical subsystems provide energy to the dual-powered vehicle. The first electrical subsystem is a power battery system, and the second electrical subsystem is one or more of a fuel cell system, an on-board generator set, and an overhead contact line power receiving device. The millimeter-wave radar, camera, road surface adhesion sensor, and weather sensor are used to collect information. The various systems and subsystems of the dual-powered vehicle communicate via a CAN bus or Ethernet. The braking system includes, but is not limited to, EBS (Electronic Braking System), ABS (Anti-lock Braking System), ESC (Electronic Stability Control), ASR (Acceleration Slip Regulation), and a motor. The motor is used for regenerative braking. The steering system is used to change or maintain the vehicle's direction of travel.

[0064] In one embodiment, such as Figure 1 As shown, a braking control method for a dual-powered vehicle is provided. Taking the application of this method to a control system as an example, the method includes the following steps:

[0065] S1. Determine the risk index of the dual-source power supply vehicle under the current operating conditions based on the vehicle parameters and the environmental parameters of the current environment.

[0066] The environmental parameters include, but are not limited to, the road surface condition (identified as wet / slippery / snowy / icy), road surface temperature (actual road surface temperature), rainfall / snowfall intensity, camera visibility distance, fog / rain / snow / dust type, altitude, ambient temperature, wind speed, wind direction, and road surface adhesion coefficient. These environmental parameters can be collected by the environmental perception module of the dual-powered vehicle. The road surface adhesion coefficient and road surface temperature can be determined through wheel speed fluctuations, road surface reflectivity, and road surface condition. The road surface adhesion coefficient can also be obtained from roadside equipment.

[0067] The environmental perception module includes a sensor submodule, a data preprocessing submodule, and a multi-source information fusion submodule. The sensor submodule includes a road condition sensor, a slope and road geometry sensor, a meteorological sensor array, and a visual / radar sensor. The structural block diagram of the environmental perception module is shown below. Figure 2 As shown.

[0068] The slope and road geometry sensor uses navigation maps, onboard inertial measurement units / accelerometers, and wheel speed information to determine the slope angle of the current road and the curvature of the road centerline from a straight line. The weather sensor array includes temperature, humidity, rain / snowfall, and wind speed / direction sensors; it identifies weather conditions such as heavy rain, heavy snow, icing, and strong crosswinds. The camera in the vision / radar sensor identifies lane lines, road surface water film and snow accumulation, sight distance markings, and traffic signs; the millimeter-wave radar / liDAR in the vision / radar sensor acquires distance and relative speed to obstacles ahead, road profile information, etc.

[0069] The data preprocessing submodule is used to filter, remove outliers, and synchronize the information signals collected by each sensor in the sensor submodule to form multi-source raw data under a unified time reference.

[0070] The multi-source information fusion submodule is used to convert the collected environmental parameters into feature vector form environmental parameters using weighted fusion, Kalman filtering, or learning-based fusion algorithms. The environmental perception module periodically outputs the feature vector form environmental parameters and their confidence levels to the operating condition judgment module. Specifically, the original environmental parameters are acquired; the original environmental parameters are preprocessed using a preset preprocessing algorithm to obtain feature vector form environmental parameters; wherein, the preprocessing algorithm is at least one of a weighted fusion algorithm, a Kalman filtering algorithm, or a machine learning-based fusion algorithm; specifically, different weight coefficients are assigned to the same environmental parameter acquired from different sensor sources, and a weighted fusion algorithm is used to perform weighted summation to obtain fused environmental parameters, which are then converted into vector form environmental parameters; the original environmental parameters are denoised using a Kalman filtering algorithm to obtain denoised environmental parameters, which are then converted into vector form environmental parameters; the trained fusion algorithm is used to perform nonlinear mapping on the original environmental parameters, outputting vector form environmental parameters.

[0071] Vehicle parameters include, but are not limited to, wheel speed, drive wheel circumference speed, brake pedal opening, ABS / ESC / ASR / EBS intervention status, longitudinal acceleration, attitude, current vehicle speed, intake air pressure / ambient pressure, cooling system operating status (such as fan speed, pump speed, radiator inlet and outlet temperatures or electric drive / power supply temperature), power requirements, vehicle driving direction, yaw rate, lateral acceleration, and steering wheel angle.

[0072] The current operating condition is determined based on at least one risk indicator. Risk indicators include, but are not limited to, low adhesion, long steep slope, low visibility, high altitude, and crosswind. Each risk indicator is determined based on the vehicle parameters of the dual-powered vehicle and the environmental parameters of the current environment. The operating condition judgment module of the dual-powered vehicle determines the current operating condition based on the environmental parameters and vehicle parameters collected by the environmental perception module. The environmental perception module and the operating condition judgment module can be integrated into a separate environmental perception controller, or they can be replaced by software function modules of the dual-powered vehicle.

[0073] The process of determining the low adhesion index includes: determining a first low adhesion index and a first confidence level based on the road surface condition in the environmental parameters and a preset first adhesion index mapping table, using the first low adhesion index as the final low adhesion index. The first adhesion index mapping table includes various road surface conditions and corresponding low adhesion indices. Alternatively, calculating the slip ratio based on the wheel circumference speed of the drive wheels of the dual-powered vehicle and the current vehicle speed, determining the first low adhesion index and a first confidence level based on the continuous over-limit duration of the slip ratio and a preset second adhesion index mapping table, using the second low adhesion index as the final low adhesion index. The second adhesion index mapping table includes various over-limit durations and corresponding low adhesion indices. Alternatively, weighted summing of the first and second low adhesion indices yields the final low adhesion index and confidence level. Wherein, the slip ratio s during driving... d The calculation formula is Slip ratio during braking b The calculation formula is v w v is the circumferential speed of the drive wheels, and v is the current vehicle speed. This is the minimum value. Continuous over-limit duration refers to the continuous duration for which the slip ratio exceeds the preset slip ratio. Further, the wheel circumference speed signal and vehicle speed signal of the drive wheels are filtered and de-glitched to obtain the current wheel circumference speed and current vehicle speed. The wheel circumference speed and current vehicle speed are data from the same moment. Further, a target low-adhesion index matching the final low-adhesion index is found from a preset low-adhesion level mapping table, and the low-adhesion level corresponding to the target low-adhesion index is determined as the low-adhesion level of the low-adhesion index and output. In addition, when the continuous over-limit duration of the slip ratio exceeds a preset duration threshold or ABS / ASR / ESC frequently intervene, it is determined that "low adhesion is established".

[0074] The process of determining the long steep slope index includes: determining the slope angle of the current driving road based on the attitude and longitudinal acceleration of the dual-powered vehicle; and determining the duration T during which the slope angle is less than the slope angle threshold. down And during the duration T down If the preset time is exceeded, through Calculate the continuous downhill distance D of a dual-powered vehicle. down; Slope angle and duration T down and continuous downhill distance D down One or more of these are identified as indicators of long, steep slopes. For example, the larger the slope angle and the longer the duration T, the better. down and continuous downhill distance D down The longer the slope, the higher the long steep slope index. Further, a target long steep slope index matching the long steep slope index is found from a pre-defined long steep slope level mapping table. The long steep slope level corresponding to the target long steep slope index is determined as the long steep slope level of the long steep slope index and output.

[0075] The process of determining low visibility indicators includes:

[0076] Step 1: Based on the detection distance and sharpness of lane lines / road edges / signs / objects in the images captured by the camera, determine the visible distance and confidence level; determine the lighting conditions through the information collected by the ambient light sensor or the brightness of the images.

[0077] Step 2: Based on the acquired images, the visibility level is obtained using image contrast attenuation and transmittance estimation methods.

[0078] Step 3: Combine lighting conditions and rain / snow intensity to determine the correction factor, and use the correction factor to correct the visibility distance to obtain the final visibility distance.

[0079] Step 4: Find the low visibility index that matches the final visibility distance from the preset low visibility mapping table, and output the low visibility index and visibility level that match the final visibility distance.

[0080] The process of determining the plateau index includes: cross-checking the navigation system with barometric altitude to obtain the altitude of the current driving road and determining the environmental pressure of the current driving road; determining the initial plateau index based on the altitude and / or environmental pressure of the current driving road; correcting the initial plateau index by the cooling load of the dual-powered vehicle to obtain the final plateau index; wherein, the initial crosswind index can be obtained by looking up the plateau index mapping table, which includes various altitudes and / or environmental pressures and their corresponding initial plateau indices. When the altitude exceeds the altitude threshold or the environmental pressure is lower than the barometric pressure threshold, the vehicle is determined to enter the plateau candidate state; in the plateau candidate state, the plateau level is determined based on the duty cycle of the cooling actuator (fan / pump), the temperature margin of key components (the margin between the current temperature and the upper limit), and the rate of temperature rise within a certain time window, and the plateau index and plateau level are output.

[0081] The process of determining the crosswind index includes: decomposing the wind direction vector according to the vehicle's direction of travel to obtain crosswind components; obtaining an initial crosswind index based on the crosswind components; correcting the initial crosswind index using yaw rate and lateral acceleration to obtain the final crosswind index and determine its crosswind level. The initial crosswind index can be obtained by looking up a crosswind index mapping table, which includes various crosswind components and their corresponding initial crosswind indices. The crosswind components and crosswind index are directly proportional. The crosswind level can be obtained by looking up a crosswind level mapping table, which includes various crosswind levels and their corresponding crosswind indices.

[0082] In some embodiments, the process of determining the level and type of the current working condition includes: obtaining a total score index by weighted summation based on at least one of the following indicators: low adhesion index, long steep slope index, low visibility index, plateau index, and crosswind index; determining a target index that matches the total score index from the working condition mapping table, and determining the working condition corresponding to the target index as the level of the current working condition; determining the type of the current working condition by the maximum value among the low adhesion index, long steep slope index, low visibility index, plateau index, and crosswind index. The weight of each risk index is determined based on the confidence level of each risk index. The types of working conditions include, but are not limited to, low adhesion, long downhill slope, low visibility, and strong crosswind. The levels of working conditions include: Level 0: Normal working condition; Level I: Mild extreme working condition (moderate rain, slightly slippery, etc.); Level II: Moderate extreme working condition (heavy rain, snow-covered road surface, general fog, etc.); Level III: Severe extreme working condition (icy long steep slope, extremely low visibility, strong crosswind, etc.). For example, if the crosswind index is the highest, the current working condition is a strong crosswind working condition. The types of working conditions include, but are not limited to, low adhesion, long downhill slope, low visibility, and strong crosswinds, which expands the application scenarios of this application and enables it to be applied to braking control in complex scenarios such as engineering transportation, mining transportation, and plateau construction.

[0083] A risk index is a numerical indicator used to quantify the level of risk on the road surface. Risk indices include, but are not limited to, the longitudinal risk index, which measures the risk in the direction of vehicle travel; the lateral risk index, which measures the risk in the left and right directions; and the visibility risk index, which measures the degree of limitation in the vehicle's environmental perception capabilities.

[0084] In some embodiments, the process of determining the level of the current operating condition includes: determining the highest level among the levels corresponding to each risk indicator as the level of the current operating condition.

[0085] In one embodiment, based on vehicle parameters and environmental parameters, the type and level of the current operating condition are determined using machine learning (such as support vector machines, decision trees, etc.) or deep learning models (such as lightweight neural networks).

[0086] S2. Based on the risk index, calculate the maximum speed of the dual-powered vehicle under the current operating conditions;

[0087] The speed limit refers to the maximum permissible speed of a dual-powered vehicle under current operating conditions. The speed limit can be calculated based on the longitudinal risk index within the risk index.

[0088] Furthermore, when the level of the current operating condition exceeds the preset level, the upper limit of the vehicle speed of the dual-source power supply vehicle under the current operating condition is calculated based on the risk index.

[0089] In one embodiment, the maximum vehicle speed under the current operating conditions can also be obtained based on a lookup table or a model prediction.

[0090] In one embodiment, under strong wind conditions, if a dual-powered vehicle is supplied with power through the traction power network, the control system immediately issues an alarm and determines the current status of the pantograph. If the pantograph is in the raised position, a forced lowering command is sent to the pantograph, and simultaneously, the high-voltage relay is activated to disconnect the contact network input circuit, seamlessly switching to the on-board battery power supply mode. By actively disconnecting the network, mechanical damage to the pantograph or short circuits in the power grid under strong winds can be avoided, ensuring uninterrupted vehicle power while maintaining physical isolation from the power grid. This avoids electrical risks such as pantograph detachment / collision / arcling caused by crosswinds, and prevents frequent switching from causing discontinuity in traction and regeneration, leading to longitudinal / lateral instability of the vehicle. Thus, under safe conditions, continuous power supply and energy feedback capabilities are maintained as much as possible. Whether the current operating condition is a strong wind condition can be determined based on the crosswind level of the crosswind index. For example, if the crosswind level reaches level three and the duration reaches the strong wind duration threshold, it is considered a strong wind condition.

[0091] In one embodiment, if the contact quality of the traction power supply network deteriorates (e.g., persistent arcing, pantograph detachment, excessive voltage / current fluctuations in the contact network triggering DCDC cabinet protection / alarms), lateral stability is abnormal (ESC / ASR high-frequency intervention, abnormally increased yaw rate / lateral acceleration, excessive lane departure), or the road section is special (e.g., known crosswind-sensitive areas such as bridges / elevated roads / tunnel entrances), a forced pantograph lowering command is sent. After pantograph lowering, traction torque limiting, vehicle speed limit reduction, and regenerative braking limit reduction are simultaneously triggered to prevent drive axle instability caused by crosswind and regenerative coupling. If on a long downhill slope requiring continuous braking energy absorption, braking stability is prioritized, and regenerative braking is reduced and mechanical braking / retarding redundancy is increased if necessary. Pantograph re-raising is only permitted after wind speed decreases and contact stability is maintained following pantograph lowering.

[0092] S3. Calculate the first deceleration based on the brake pedal opening and current vehicle speed of the dual-powered vehicle, and calculate the second deceleration based on the current vehicle speed and the upper limit of vehicle speed.

[0093] Furthermore, if the second deceleration exceeds the deceleration threshold, the second deceleration is adjusted to the deceleration threshold so that the total braking force required for the dual-source power supply vehicle to decelerate is calculated using the maximum value between the first deceleration and the deceleration threshold.

[0094] When the current speed of a dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, the control system will send a braking request to the braking system to decelerate.

[0095] S4. Calculate the total braking force required for the deceleration of the dual-powered vehicle based on the maximum value of the first deceleration and the second deceleration.

[0096] Among them, the maximum value 'a' of the first deceleration and the second deceleration is selected. req The expression is Furthermore, if the maximum value a req Exceeding the maximum threshold Then the maximum value a req Adjust to maximum threshold Based on the maximum threshold, the total braking force required for deceleration of a dual-source powered vehicle is calculated. Where g is the road surface adhesion coefficient, and g is the acceleration due to gravity. The slope angle of the current driving road. Furthermore, the rate of change of the maximum value of the first deceleration and the second deceleration is always kept less than a preset rate of change.

[0097] In some embodiments, S4 includes: calculating the total braking force required for the deceleration of the dual-powered vehicle based on the maximum value of the first deceleration and the third deceleration; the third deceleration is the maximum value of the second deceleration, the deceleration required by the dual-powered vehicle's AEB (Autonomous Emergency Braking) system, and the deceleration required by following other vehicles.

[0098] In some embodiments, the maximum value of the first deceleration and the second deceleration may be used as the total braking force, or the wheel braking torque may be used as the final total braking force. Wheel braking torque T brk,req The formula is F brk,req R is the initial total braking force obtained based on the maximum value of the first deceleration and the second deceleration. w For the wheel radius, For transmission efficiency.

[0099] S5. When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, brake control is applied to the dual-powered vehicle using total braking force.

[0100] The aforementioned braking control method for dual-powered vehicles determines the risk index of the dual-powered vehicle under the current operating conditions based on the vehicle parameters and environmental parameters of the current environment. Based on the risk index, the upper speed limit of the dual-powered vehicle under the current operating conditions is calculated. This allows for dynamic adjustment of the upper speed limit. Consequently, when calculating the second deceleration based on the current speed and the upper speed limit, a second deceleration suitable for the current operating conditions is obtained. Therefore, when calculating the total braking force required for deceleration of the dual-powered vehicle based on the maximum value of the first and second decelerations, the calculated total braking force ensures that the dual-powered vehicle can safely travel on the road, improving braking safety.

[0101] In one embodiment, extreme condition data and control effects are recorded during the braking process of a dual-powered vehicle, and uploaded to a cloud platform via a communication module to provide data support for subsequent strategy optimization. Communication with the cloud platform can be achieved through cellular networks, dedicated wireless networks, or vehicle-to-infrastructure (V2I) communication. By communicating with the cloud platform, roadside perception information can be utilized to further improve the accuracy of extreme condition identification and the adaptability of braking control strategies.

[0102] In one embodiment, step S5 includes:

[0103] Based on the distances between the center of mass of the dual-powered vehicle and the front and rear axles of the dual-powered vehicle, calculate the normal load on the front axle and the normal load on the rear axle.

[0104] Calculate the maximum available braking force of the front axle based on the front axle normal load and the road adhesion coefficient of the current driving surface; calculate the maximum available braking force of the rear axle based on the rear axle normal load and the road adhesion coefficient.

[0105] Based on the front axle normal load F z,f and rear axle normal load F z,r Through formula Calculate the first front axle distribution ratio ;

[0106] Based on total braking force F brk,rep Distribution ratio with the first front axle ,pass and The first candidate braking force to be allocated to the front axle in the calculation of total braking force. and the second candidate braking force allocated to the rear axle ;

[0107] The minimum value between the first candidate braking force and the maximum available braking force of the front axle is determined as the first front axle braking force to be allocated to the front axle; the total braking force minus the first front axle braking force is calculated; the minimum value between the subtraction result and the maximum available braking force of the rear axle is determined as the first rear axle braking force to be allocated to the rear axle.

[0108] When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on the first front axle braking force and the first rear axle braking force.

[0109] Among them, the front axle normal load F z,f The calculation formula is Rear axle normal load F z,r The calculation formula is m is the mass, a is the distance from the center of mass to the front axis, b is the distance from the center of mass to the rear axis, L = a + b, and h is the height of the center of mass above the ground.

[0110] The maximum available braking force of the front axle refers to the maximum effective force that the front axle can provide to decelerate a dual-powered vehicle during braking. The maximum available braking force of the rear axle refers to the maximum effective force that the rear axle can provide to decelerate a dual-powered vehicle during braking. (The last two sentences are a repetition of the previous two and can be omitted.) The calculation formula is Maximum available braking force of the rear axle The calculation formula is .

[0111] In this embodiment, the normal loads of the front and rear axles are calculated based on the distances between the center of mass of the dual-powered vehicle and the front and rear axles, respectively. The maximum available braking force of the front axle is calculated based on the normal load of the front axle and the road adhesion coefficient of the current driving surface. Similarly, the maximum available braking force of the rear axle is calculated based on the normal load of the rear axle and the road adhesion coefficient. The maximum available braking force of the rear axle is also calculated based on the normal load F of the front axle. z,f and rear axle normal load F z,r Through formula Calculate the first front axle distribution ratio Based on total braking force F brk,rep Distribution ratio with the first front axle ,pass and The first candidate braking force to be allocated to the front axle in the calculation of total braking force. and the second candidate braking force allocated to the rear axle The minimum value between the first candidate braking force and the maximum available braking force of the front axle is determined as the first front axle braking force to be allocated to the front axle; the total braking force is calculated by subtracting the first front axle braking force from the total braking force; the minimum value between the subtraction result and the maximum available braking force of the rear axle is determined as the first rear axle braking force to be allocated to the rear axle; when the current speed of the dual-source power supply vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is performed on the dual-source power supply vehicle based on the first front axle braking force and the first rear axle braking force. This allows for intelligent allocation of braking force according to the real-time force conditions of the front and rear axles, maximizing braking efficiency, improving vehicle stability, and reducing tire wear.

[0112] In one embodiment, the method further includes:

[0113] If based on the first front axle braking force F x,f1 and the first rear axle braking force F x,r1 When braking a dual-powered vehicle, if the vehicle speed cannot be reduced to the recommended speed range or the vehicle cannot drive stably, then... Calculate the second front axle distribution ratio ;

[0114] Based on the second front axle distribution ratio, calculate the second front axle braking force distributed to the front axle and the second rear axle braking force distributed to the rear axle in the total braking force;

[0115] When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on the second front axle braking force and the second rear axle braking force.

[0116] The recommended speed range is the speed range that can ensure traffic efficiency and allow sufficient reaction time under the current operating conditions.

[0117] The second front axle braking force is the product of the second front axle distribution ratio and the total braking force. The second rear axle braking force is the total braking force minus the second front axle braking force.

[0118] Furthermore, through The second front axle braking force is converted into front axle braking torque T. f The second rear axle braking force is converted into rear axle braking torque T. r To reduce speed through the braking torque of the front axle and the braking torque of the rear axle, R w The wheel radius is set for vehicles powered by dual power sources. Simultaneously, the rate of change and maximum torque of the drive axle are limited under conditions such as low adhesion or cornering to prevent drive wheel slippage; under conditions such as high altitude or low temperature, thermal management limitations of the motor and power system are considered, and the peak torque command is appropriately reduced.

[0119] In this embodiment, through Calculate the second front axle distribution ratio Based on the second front axle distribution ratio, the second front axle braking force and the second rear axle braking force distributed in the total braking force are calculated. When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on the second front axle braking force and the second rear axle braking force. This allows the dual-powered vehicle to decelerate to the recommended speed range when it cannot decelerate to the recommended speed range, while ensuring stable driving of the dual-powered vehicle.

[0120] In one embodiment, the calculation process for the second front axle allocation ratio includes: when the low adhesion level increases or the lateral risk index increases, by... Determine the second front axle allocation ratio. The allocation margin increases with the rise of the horizontal risk index and the low attachment level. The allocation margin can be obtained by looking up a table based on the horizontal risk index or the low attachment level.

[0121] In one embodiment, if the rear axle slippage rate exceeds the limit or the ABS frequently intervenes at the rear axle, the second front axle allocation ratio is further increased; conversely, if the front axle intervenes first, the second front axle allocation ratio is decreased. The increased and decreased values ​​can be determined by looking up a table based on the number of ABS interventions or the duration of slippage exceeding the limit.

[0122] In one embodiment, step S5 includes:

[0123] Based on vehicle parameters, the state parameters of the motor in the dual-source power supply vehicle, and the road surface adhesion coefficient of the current driving surface, the upper limit of the regenerative braking force of the motor is determined; based on the risk index and the state parameters of the motor, the target regenerative ratio is determined.

[0124] Based on the upper limit of regenerative braking force and the target regenerative ratio, determine the motor power required to be provided by the motor and the mechanical braking force required to be provided by the mechanical braking device in dual-source power supply vehicles in the total braking force.

[0125] When the current speed of a dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on electric motor power and mechanical braking force.

[0126] The upper limit of the regenerative braking force of the motor refers to the maximum braking force that the motor can provide in generator mode. The road surface adhesion coefficient is an indicator that measures the strength of the "grip" between the tire and the road surface.

[0127] The motor's status parameters include its current temperature and current speed. Vehicle parameters include the system status of the dual-powered vehicle and the DC circuit voltage between the motor and the dual-powered vehicle's battery.

[0128] Electric motor power The definite expression is: That is, calculating the target regeneration ratio The product of the total braking force and the regenerative braking force is then combined with the upper limit of the regenerative braking force. The minimum value in the equation is determined as the power source for the electric motor.

[0129] Mechanical braking force This is the result of subtracting the motor's power from the total braking force. The expression is: .

[0130] Mechanical braking devices include, but are not limited to, ABS, ASR, and ESC.

[0131] In a specific application, under long and steep slope conditions, the reverse drag of the motor and the absorption capacity of the second power subsystem can be used to carry out continuous braking, reducing the thermal load of mechanical braking; under high temperature or high altitude conditions, when the temperature of a certain power subsystem approaches the upper limit, power reduction operation is performed, and redundancy is provided by another power subsystem.

[0132] In this embodiment, the upper limit of the regenerative braking force of the motor is determined based on vehicle parameters, the state parameters of the motor in the dual-source power supply vehicle, and the road adhesion coefficient of the current driving surface. The target regenerative ratio is determined based on the risk index and the state parameters of the motor. Based on the upper limit of the regenerative braking force and the target regenerative ratio, the electric motor power required to be provided by the motor and the mechanical braking force required to be provided by the mechanical braking device in the dual-source power supply vehicle are determined. When the current speed of the dual-source power supply vehicle reaches the upper limit and the risk index is higher than the risk threshold, braking control is performed on the dual-source power supply vehicle based on the electric motor power and the mechanical braking force. This ensures that braking stability and power safety are prioritized in extreme working conditions, and energy recovery is carried out as much as possible on this basis, taking into account both safety and economy, and preventing instability caused by pursuing energy recovery.

[0133] In one embodiment, the upper limit of regenerative braking force and the target regenerative ratio can be determined by the braking energy recovery module of a dual-powered vehicle.

[0134] In one embodiment, the electric motor outputs motor power and the mechanical braking device outputs mechanical braking force to control the braking of the dual-powered vehicle. ESC / ABS monitors wheel slip rate and vehicle attitude in real time. If an instability trend occurs (the number of ESC / ABS interventions exceeds the limit or the wheel slip rate exceeds a preset threshold), the motor power is reduced and compensated by the mechanical braking force.

[0135] In some embodiments, under the premise of meeting safety and power protection constraints, priority is given to utilizing long-term downhill conditions for deep energy recovery; alternatively, fine-tuning of the electric motor's power and mechanical braking force through optimization algorithms can be used to increase the total amount of recovered energy. Fine-tuning of the electric motor's power and mechanical braking force can be achieved through the braking energy recovery module of a dual-powered vehicle.

[0136] In one embodiment, candidate electric motor braking force is determined based on the product of a fixed ratio and the total braking force, and the candidate electric motor braking force is subjected to amplitude limiting processing to obtain the electric motor braking force. Based on the difference between the total braking force and the electric motor braking force, candidate mechanical braking force is determined, and the candidate mechanical braking force is subjected to amplitude limiting processing to obtain the mechanical braking force.

[0137] In one embodiment, the upper limit of regenerative braking force can be determined using a linear function, piecewise linear function, or fuzzy control function, as long as energy recovery is improved while meeting safety constraints. The optimization objective for energy recovery can consider only the recovered energy, or it can simultaneously consider multiple objectives such as battery life and thermal management load. The motor can be a drive motor, or it can be combined with wheel-side motors, integrated motors, etc.

[0138] In one embodiment, the calculation process for the upper limit of regenerative braking force includes:

[0139] The upper limit of the regenerative torque of the motor is determined based on the current temperature and speed of the motor, the system status of the dual-source power supply vehicle, and the DC circuit voltage between the motor and the battery of the dual-source power supply vehicle.

[0140] Based on the upper limit of regenerative torque The wheel radius R of a dual-source powered vehicle w Transmission efficiency The overall speed ratio i is obtained through... Calculate the upper limit of wheel axial force F for a dual-source powered vehicle. m,lim Determine the upper limit of the maximum regenerative braking force, the upper limit of the available longitudinal force for drive shaft attachment, and the upper limit of the global safety limiting force for dual-source powered vehicles;

[0141] The minimum value among the upper limit of wheel axial force, the upper limit of maximum regenerative braking force, the upper limit of available longitudinal force for drive shaft attachment, and the upper limit of global safety limiting force is determined as the upper limit of regenerative braking force.

[0142] The system status is a comprehensive flag, including but not limited to vehicle mode (e.g., Sport / Economy mode) and fault status (e.g., whether overcurrent protection is triggered). The upper limit of the motor's regenerative torque is the maximum reverse drag torque the motor can generate. Transmission efficiency is the proportion of braking force that actually reaches the wheels during transmission. The overall speed ratio is the ratio of the motor speed to the wheel speed.

[0143] Specifically, based on the motor's current temperature and speed, the system status of the dual-powered vehicle, and the DC circuit voltage between the motor and the vehicle's battery, an upper limit of regenerative torque associated with these factors is determined from the motor's calibration mapping table. This upper limit is then used as the motor's upper limit of regenerative torque. The expression is f m To calibrate the mapping table, n m For the current rotational speed, U dc T is the voltage of the DC circuit. m The current temperature is 'state', and the system state is 'state'.

[0144] The upper limit of wheel axial force refers to the maximum linear braking force that the motor can apply to the point of contact between the wheel and the ground through energy recovery.

[0145] The maximum regenerative braking force limit refers to the maximum total power that the vehicle's current energy recovery system (battery, grid, resistors, etc.) can withstand, converted into ground braking force. The calculation formula is and . The maximum total power that can be recovered for a dual-source power supply vehicle is the total power that can be recovered by combining all the components of the dual-source power supply vehicle that can currently consume or store electrical energy. The maximum charging power of the battery for a dual-source powered vehicle, SOC is the battery's state of charge, T bat This refers to the battery temperature. This refers to the maximum power fed back to the grid by a dual-source power supply vehicle. Grid availability refers to whether the external power grid allows access. DC-DC status refers to whether the on-board DC-DC converter of the dual-source power supply vehicle is working properly. It is the maximum power of the braking resistor in a dual-source powered vehicle.

[0146] The maximum usable longitudinal force for drive shaft adhesion refers to the maximum grip that the ground can provide to the drive wheels without them slipping. The calculation formula is and , For the driving shaft normal load, Let m be the static load on the drive shaft, h be the mass of the dual-powered vehicle, h be the height of the vehicle's center of mass from the ground, and L be the sum of the distances between the center of mass and the front axle and the rear axle. For safety margin coefficient, , This is the road surface adhesion coefficient.

[0147] The global safety limit force is an absolute and insurmountable upper limit of braking force that the control system forcibly sets when a vehicle is performing regenerative braking to prevent hardware damage or system malfunction. This limit is based on the real-time hardware health status (temperature, fault condition) and external energy status (power grid connection). The global safety limit force includes system-level constraints such as temperature limits, fault derating, and power grid unavailability.

[0148] Furthermore, if ABS / ESC intervenes or the slip ratio of the drive wheel exceeds the threshold, the upper limit of the available longitudinal force for drive shaft attachment will be adjusted to a preset conservative value or to zero.

[0149] Furthermore, constraints are imposed on the rate of change of the upper limit of regenerative braking force to avoid abrupt changes in the upper limit of regenerative braking force. Specifically, , This represents the change in the upper limit of regenerative braking force. For the time change, The rate of change threshold, This represents the rate of change of the upper limit of regenerative braking force.

[0150] In this embodiment, the upper limit of the regenerative torque of the motor is determined based on the motor's current temperature and speed, the system status of the dual-source power supply vehicle, and the DC circuit voltage between the motor and the battery of the dual-source power supply vehicle; based on the upper limit of the regenerative torque... The wheel radius R of a dual-source powered vehicle w Transmission efficiency The overall speed ratio i is obtained through... Calculate the upper limit of wheel axial force F for a dual-source powered vehicle. m,lim Determine the upper limit of the maximum regenerative braking force, the upper limit of the available longitudinal force for drive shaft attachment, and the upper limit of the global safety limiting force for dual-source power supply vehicles; determine the minimum value among the upper limit of wheel axial force, the upper limit of the maximum regenerative braking force, the upper limit of the available longitudinal force for drive shaft attachment, and the upper limit of the global safety limiting force as the upper limit of regenerative braking force. This can prevent battery damage and ensure driving safety when braking control is based on the upper limit of regenerative braking force.

[0151] In one embodiment, the calculation process for the target regeneration percentage includes:

[0152] The initial proportion is determined based on the battery status of the dual-powered vehicle, its connection status with the external power grid, and the downhill slope index in the risk indicators of the dual-powered vehicle; based on the maximum value R in the risk index, through... Determine the correction factor f for the initial proportion risk ; f is the first preset value. minf is the preset lower cutoff limit. max `clip` is the preset upper limit for truncation; `clip` is the truncation function.

[0153] When the total braking force is greater than the second preset value, the ratio of the upper limit of regenerative braking force to the total braking force is determined as the first candidate percentage; the product of the initial percentage and the correction coefficient is determined as the second candidate percentage.

[0154] The minimum of the first candidate percentage and the second candidate percentage is determined as the target regeneration percentage.

[0155] The battery status includes the battery's state of charge and battery temperature. The initial percentage is obtained by querying a preset percentage table. Specifically, the percentages associated with the battery status, external power grid connection status, and downhill slope indicator in the risk indicators of the dual-powered vehicle are determined from the preset percentage table, and these associated percentages are set as the initial percentages. The target regeneration percentage is inversely proportional to the operating condition level.

[0156] Furthermore, if ABS / ESC intervenes or the wheel slip rate exceeds the limit, the correction factor is zero.

[0157] Furthermore, if the total braking force is less than or equal to the second preset value, the proportion of the first candidate is determined as the third preset value. Further, the third preset value is 1.

[0158] Furthermore, the lower cutoff limit for the correction factor is 0, and the upper cutoff limit is 1.

[0159] In this embodiment, the initial proportion is determined based on the battery status of the dual-powered vehicle, its connection status with the external power grid, and the steep slope index in the risk indicators of the dual-powered vehicle; based on the maximum value R in the risk index, through... Determine the correction factor f for the initial proportion risk When the total braking force is greater than the second preset value, the ratio of the upper limit of regenerative braking force to the total braking force is determined as the first candidate ratio; the product of the initial ratio and the correction coefficient is determined as the second candidate ratio; the minimum value between the first candidate ratio and the second candidate ratio is determined as the target regenerative ratio. In this way, the electric motor power and mechanical braking force can be determined based on the target regenerative ratio, ensuring that the battery will not be damaged during the braking control of the dual-source power supply vehicle based on the electric motor power and mechanical braking force, while also ensuring driving safety.

[0160] In one embodiment, the calculation process of the longitudinal risk index in step S1 includes:

[0161] Based on the maximum permissible deceleration of a dual-powered vehicle on the current road surface. The acceleration a caused by the slope grade and the expected deceleration areq1 ,pass Calculate the deceleration margin of a dual-powered vehicle; based on the deceleration margin M dec ,pass Obtain the deceleration margin sub-risk r dec risk is a mapping function;

[0162] Based on the current vehicle speed v and the preset safe vehicle speed v of the dual-source powered vehicle safe ,pass Obtaining the risk of hypervelocities r spd ;

[0163] Current temperature T of the brake in a dual-powered vehicle b and temperature threshold T warn ,pass Obtaining thermal decay risk r heat ;

[0164] Based on the weighted summation of the deceleration margin sub-risk, overspeed sub-risk, and thermal decay sub-risk, the longitudinal risk index in the risk index is determined, and the upper limit of vehicle speed is calculated through the longitudinal risk index.

[0165] The maximum permissible deceleration refers to the maximum braking force that the vehicle is currently allowed to exert. The calculation formula is . denoted as the road surface adhesion coefficient, and g is the acceleration due to gravity.

[0166] Glide acceleration a grade The calculation formula is . The slope angle of the current road.

[0167] Expected deceleration a req1 The calculation formula is v represents the current vehicle speed. safe The preset safe speed v safe d look This refers to the preset forward-looking distance or strategic preview distance. The forward-looking distance or strategic preview distance refers to the length of the road ahead that the control system or driver needs to observe in order to make optimal decisions.

[0168] The deceleration margin risk measures whether the remaining braking capacity is sufficient to handle unexpected situations. The overspeed risk measures the degree to which the current vehicle speed exceeds the safe speed. The brake fade risk measures the likelihood that the braking system will degrade in performance due to overheating, thus leading to a dangerous situation.

[0169] Vertical risk index R v The formula for determining is w1 is the weight of the deceleration margin risk, w2 is the weight of the overspeed risk, w3 is the weight of the thermal decay risk, clip is the cutoff function, and R... min R is the cutoff lower limit of the longitudinal risk index. max This represents the upper cutoff value for the longitudinal risk index. Furthermore, the lower cutoff value for the longitudinal risk index is 0, and the upper cutoff value is 1.

[0170] In this embodiment, the maximum permissible deceleration of the dual-source powered vehicle on the current road surface is used as the basis. The acceleration a caused by the slope grade and the expected deceleration a req1 ,pass Calculate the deceleration margin of a dual-powered vehicle; based on the deceleration margin M dec ,pass Obtain the deceleration margin sub-risk r dec Based on the current vehicle speed v and the preset safe vehicle speed v of the dual-powered vehicle safe ,pass Obtaining the risk of hypervelocities r spd The current temperature T of the brakes in a dual-powered vehicle b and temperature threshold T warn ,pass Obtaining thermal decay risk r heat Based on the weighted summation of the deceleration margin sub-risk, overspeed sub-risk, and thermal decay sub-risk, the longitudinal risk index in the risk index is determined. In this way, the upper limit of vehicle speed that meets the current operating conditions can be calculated through the longitudinal risk index.

[0171] In one embodiment, the calculation process of the lateral risk index includes: using the current vehicle speed v and the curvature R... curve ,use Calculate the ideal lateral acceleration a y,req ;pass Calculate the lateral adhesion limit capacity a y,max ;pass Calculate the lateral margin M lat The desired yaw rate r is calculated using a reference vehicle model (two-degree-of-freedom model) of a dual-powered vehicle. ref And obtain the actual angular velocity r, through The difference in angular velocity e is obtained. r ;pass Determine the horizontal margin risk r lat ;pass Determine the risk of yaw anomaly r yaw ;pass Determine crosswind risk r cw ,pass Calculate the horizontal risk index Rh w4 represents the weight of lateral margin risk, w5 represents the weight of yaw anomaly risk, w6 represents the weight of crosswind risk, clip is the cutoff function, and f Rmin f is the cutoff lower limit of the horizontal risk index. Rmax V is the upper cutoff value of the longitudinal risk index. cw V represents the actual crosswind speed. cw,th Let x be the desired crosswind speed. `risk(x)` represents retrieving the data associated with x from the corresponding mapping table. For example, This indicates retrieving the difference between the angular velocity e and the angular velocity from the mapping table. r Related data, and the data found is used as the basis for identifying horizontal anomaly risks.

[0172] In scenarios with strong crosswinds or slippery curves, abnormal yaw / lateral acceleration leads to an increased lateral risk index. Furthermore, this is analyzed through the relationship... Adjusting the upper limit of drive torque T max ,pass Limiting the rate of change of torque ;K rate This is a limiting factor. When ESC intervenes frequently or the wheel slip rate exceeds the limit, the lateral risk index can be directly raised to a high value range (or a lower limit can be set), thereby immediately triggering stricter torque limiting, speed limiting, and regenerative reduction, forming a rapid "stability maintenance" effect. This can create a mode where the higher the lateral risk index, the more "gentle and conservative" the vehicle output, reducing the risk of yaw amplification and fishtailing in crosswind / slippery conditions.

[0173] The lateral risk index and crosswind level can be used for "pantograph lowering / dual-source switching" adjustment. Specifically, when strong crosswinds cause fluctuations in pantograph-catenary contact quality and deteriorate lateral stability, if the lateral risk index increases and the pantograph-catenary quality indicators worsen (arcling / fluctuation exceeding limits), pantograph lowering is triggered and switching to battery power is initiated. At the same time, the speed limit, torque limit, and regenerative braking upper limit are lowered to prevent longitudinal / lateral instability during switching. This achieves a synergy between electrical safety and driving stability.

[0174] In one embodiment, the visibility risk index R v2 The determination process is as follows: determine the current visible distance, and through... Calculate the safe parking distance D stop , t react For the equivalent reaction time, a eff For usable effective deceleration, ;pass Calculate the visibility margin M vis ,pass Determine the visibility margin risk r vis ; visible margin risk r vis As a visibility risk index R v2or through Determine the visibility risk index R v2 w7 represents the weight of visibility margin risk, and w8 represents the weather risk r. weather The weight, Rv min Rv is the cutoff lower limit for the visibility risk index. max This represents the upper cutoff value for the visibility risk index. Visibility distance can be estimated through camera image processing or obtained from vehicle-to-infrastructure communication (V2I) information about visibility on the road ahead. The lower cutoff value for the visibility risk index is 0, and the upper cutoff value is 1.

[0175] The visibility risk index can be used to adjust aiming distance, following strategy, and speed limits. In foggy or heavy rain scenarios, visibility is low, so the visibility risk index increases. Furthermore, adjustments can be made using the visibility risk index by: calculating a more conservative speed limit based on the index, or by using the constraint that "stopping distance is less than visibility distance" to inversely calculate the speed limit, resulting in a pattern where the lower the visibility distance, the lower the speed limit.

[0176] In some embodiments, the process for determining the current operating condition level of a dual-source powered vehicle further includes: determining the operating condition level corresponding to the maximum value among the longitudinal risk index, the lateral risk index, and the visibility risk index as the current operating condition level, or based on... Calculate the total risk score, and determine the working condition level corresponding to the total risk as the level of the current working condition. A1 is the weight of the vertical risk index, A2 is the weight of the horizontal risk index, and A3 is the weight of the visibility risk index.

[0177] In one embodiment, the working condition level determined by the risk index is used as the candidate level, and the working condition level determined by the maximum value in the risk index or the total score is used as the corrected level. If the candidate level and the corrected level are inconsistent, the corrected level is used as the final level of the current working condition.

[0178] In one embodiment, calculating the vehicle speed limit using the longitudinal risk index includes:

[0179] Obtain the baseline speed limit for the current road surface;

[0180] Based on the baseline speed limit v base and longitudinal risk index R v ,pass The maximum speed v of the dual-powered vehicle under the current operating conditions is obtained. max K v These are calibration coefficients.

[0181] The baseline speed limit is the maximum speed permitted by current road laws and regulations.

[0182] Automatic deceleration is triggered when the current vehicle speed reaches or exceeds the speed limit and the longitudinal risk index exceeds the risk threshold. During deceleration, the electric braking force within the stable range is used first, and mechanical braking force is supplemented when the electric braking force is insufficient or limited. If there is a risk of brake heat or decreased adhesion, the mechanical braking redundancy is increased and the upper limit of regenerative braking force is reduced.

[0183] If the increase in longitudinal risk index is mainly caused by continuous braking on a long downhill slope, and the energy absorption capacity is insufficient (high battery SOC, unusable power grid, etc.), then the vehicle speed limit will be further reduced, and the driver will be prompted to enter low-speed safety mode to avoid overheating of mechanical brakes.

[0184] In this embodiment, based on the reference speed limit v base and longitudinal risk index R v ,pass The maximum speed v of the dual-powered vehicle under the current operating conditions is obtained. max This allows for a pattern where a higher longitudinal risk index corresponds to a lower speed limit, resulting in a more conservative speed boundary. Furthermore, the longitudinal risk index can transform the question from "whether to limit speed" to "to what extent to limit speed," reducing the risk of speeding.

[0185] In one embodiment, step S5 includes:

[0186] Obtain the preset speed margin and the lower limit of the recommended speed range for dual-source powered vehicles on the current road surface;

[0187] The result of subtracting the speed margin from the maximum speed limit is determined as the upper limit of the recommended speed range.

[0188] When the current speed of a dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, the total braking force is used to brake the dual-powered vehicle so that the speed of the dual-powered vehicle is within the recommended speed range.

[0189] Speed ​​margin is the difference between the upper limit of vehicle speed and the upper limit of the recommended speed range. It is used to measure the safety margin or potential for improvement of the system in terms of speed. Speed ​​margin can increase with the increase of operating condition level and risk index (the higher the risk, the larger the buffer zone).

[0190] The current vehicle speed is within the recommended speed range. During this period, no mandatory intervention will be implemented; at the current vehicle speed... When the vehicle speed exceeds the speed limit, a warning and mild intervention (such as gradual torque limiting / light braking) will be implemented. max When necessary, forceful intervention may be implemented (such as strong torque limiting / enhanced braking / more stringent regenerative braking). high v is the upper limit of the recommended speed range. lowThis is the lower limit of the recommended vehicle speed range.

[0191] When the current vehicle speed exceeds or reaches the speed limit v max When the vehicle speed is reduced, the control system limits the actual drive output by issuing a limit on the upper limit / slope of the drive torque (or power), thereby gradually reducing the vehicle speed and stabilizing it near the upper limit. In this way, even if the driver presses the accelerator hard, the actual torque is constrained, and the vehicle is unlikely to continue to accelerate beyond the upper limit. If there is still a tendency to exceed the speed limit, a stronger torque limiting or braking intervention will be triggered.

[0192] In this embodiment, a preset speed margin and the lower limit of the recommended speed range for the dual-powered vehicle on the current road surface are obtained; the upper limit of the recommended speed range is determined by subtracting the speed margin from the upper limit of the speed; when the current speed of the dual-powered vehicle reaches the upper limit of the speed and the risk index is higher than the risk threshold, the total braking force is used to brake the dual-powered vehicle so that the speed of the dual-powered vehicle is within the recommended speed range, thus ensuring the safe driving of the vehicle.

[0193] In one embodiment, the instrument panel or central control screen displays the current operating condition level, vehicle speed limit, and recommended speed range; when the current operating condition level reaches level three, the driver is prompted to enter the "extreme operating condition safety mode" and it is explained that some performance characteristics (such as maximum speed and acceleration capability) are limited.

[0194] In one embodiment, the method further includes:

[0195] Based on electric motor power And the current vehicle speed v, through Calculate the first candidate regeneration power The minimum value among the upper limit of motor regenerative power, upper limit of absorption capacity, upper limit of DC bus voltage constraint power, upper limit of stability power constraint power and preset safety upper limit is the second candidate regenerative power.

[0196] The minimum of the candidate regenerative power and the second candidate regenerative power is determined as the desired regenerative power of the motor, so as to perform braking control based on the desired regenerative power.

[0197] The upper limit of motor regenerative power refers to the maximum power that the motor and its associated inverter can output under physical and thermodynamic constraints. The calculation formula is , This is the upper limit of regenerative torque. This represents the motor speed.

[0198] The upper limit of absorption capacity is the sum of the upper limit of battery recovery power, the upper limit of wire network feedback power, and the upper limit of power consumption.

[0199] The upper limit of battery recovery power is the maximum rate of electrical energy that a dual-source powered vehicle's battery can safely and stably receive under current conditions. The definite expression is and The upper limit of battery recycling power can also be directly based on... The result is obtained. Here, SOC represents the battery's state of charge, and T... bat For battery temperature, V cell This refers to the individual cell voltage within the battery, while "battery state" refers to the system state of the battery. U is the upper limit of the battery's current. bat Where is the battery voltage, and 'f' indicates a lookup table. The higher the state of charge, the lower / higher the battery temperature, and the closer the individual cell voltage is to the upper limit, the lower the upper limit of the battery's regenerative power. Furthermore, triggering overvoltage / overtemperature / low temperature protection will also cause the upper limit of the battery's regenerative power to drop rapidly or even to zero.

[0200] The upper limit of regenerative braking power is the maximum regenerative braking power that the traction power supply network (overhead catenary / third rail) supplying power to dual-source powered vehicles can safely receive and process. The definite expression is The grid power status refers to whether the traction power supply network is available. grid The voltage of the traction power supply network. The DC-DC_state setting represents the upper limit of the traction power supply network current. It indicates whether the onboard DC-DC converter in a dual-source power supply vehicle is functioning correctly. If the traction power supply network is unavailable, or if feedback / pantograph lowering is not permitted, the upper limit of the network feedback power is zero.

[0201] The upper limit of power consumption refers to the maximum power that energy-consuming devices (such as braking resistors) used to dissipate excess energy in a dual-powered vehicle can withstand. Based on the temperature T of the energy-consuming device dump and state dump Confirmed, the expression is If a dual-powered vehicle does not have an energy-consuming device to dissipate excess energy, then the maximum energy consumption is zero.

[0202] When battery absorption is limited (high / low SOC), but grid power can be fed back, the regenerative power is preferentially allocated to the grid feedback channel for recovery; when both are limited, the regenerative power is automatically reduced and compensated by mechanical braking.

[0203] The upper limit of DC bus voltage constraint refers to the maximum allowable value of the DC bus voltage in the traction power supply network, set to prevent equipment damage due to excessive voltage. The calculation formula is , U is the DC bus voltage threshold. dc Here, k is the DC circuit voltage (the actual voltage of the DC bus), and k1 is the control gain coefficient. Further, if the upper limit of the DC bus voltage constraint is greater than the preset upper limit threshold of the DC bus voltage constraint, then the upper limit of the DC bus voltage constraint is adjusted to the upper limit threshold of the DC bus voltage constraint. When... When this occurs, the desired regeneration power should be quickly reduced to zero or a minimum value to avoid triggering the overvoltage protection.

[0204] The upper limit of the stability power constraint refers to the upper limit of power after conversion from the upper limit of regenerative braking force. Based on the upper limit of regenerative braking force The current vehicle speed v is determined, and the specific expression is: Furthermore, if ABS / ESC intervenes or the wheel slip ratio exceeds the limit, "regenerative rapid reduction" will be executed directly, that is, the upper limit of the stability power constraint will be adjusted to zero or a minimum value.

[0205] The preset safety limit refers to the maximum permissible value of regenerative power that is dynamically set in advance based on the current operating conditions or risk index during vehicle operation. The formula for calculating the preset safety limit is as follows: or , As a preset safety factor, P cap The rated power for vehicles with dual power sources, where R is the risk index. It decreases as the severity of the working conditions increases.

[0206] Furthermore, through Desired regeneration power Converted into torque or through Convert the desired regenerative power into current. Braking control can be achieved by directly controlling the electromagnetic torque of the motor through torque, or by controlling the magnitude of the current output by the motor controller (inverter) through current.

[0207] In this embodiment, power is generated based on an electric motor. And the current vehicle speed v, through Calculate the first candidate regeneration power The minimum value among the upper limit of motor regenerative power, upper limit of absorption capacity, upper limit of DC bus voltage constraint power, upper limit of stability power constraint, and preset safety upper limit is used as the second candidate regenerative power. The minimum value between the candidate regenerative power and the second candidate regenerative power is determined as the expected regenerative power of the motor. In this way, under the premise of ensuring that the battery does not explode, the motor does not burn out, and the vehicle does not slip, the amount of electricity that the vehicle can recover at this moment can be determined, and the motor can be directed to work accordingly.

[0208] In one embodiment, the first candidate regenerative power is determined by: based on the desired regenerative torque. and motor speed ,pass Calculate the first candidate regeneration power .

[0209] Furthermore, through Rate of change of expected regeneration power To impose constraints, The threshold value represents the rate of change of the desired regeneration power.

[0210] In some embodiments, the generation of the vehicle speed limit, the calculation of total braking force, the calculation of the first front axle braking force and the first rear axle braking force, the calculation of the second front axle braking force and the second rear axle braking force, the calculation of the electric motor braking force and the mechanical braking force, and braking control can be executed through the safety control module of the dual-powered vehicle. The safety control module is connected to the operating condition judgment module and the vehicle's power system and braking system. Each module can be centrally deployed in a high-performance VCU (Vehicle Control Unit) or distributed in multiple ECUs (Electronic Control Units). The modules can be interconnected via buses such as CAN, Ethernet, and FlexRay.

[0211] In a specific scenario, the overall structure diagram of the control system is as follows: Figure 3 As shown, the environmental perception module outputs environmental and vehicle parameters to the operating condition judgment module. The operating condition judgment module outputs the type, level, and risk index of the current operating condition. The safety control module distributes braking force, the braking energy recovery module optimizes braking force, and the motor and mechanical braking devices control braking.

[0212] In a specific scenario, the overall flowchart of the safety assurance and control method under extreme conditions is as follows: Figure 4As shown. Specifically, environmental and vehicle parameters are periodically acquired to identify the type and level of the current operating condition. Based on the level of the current operating condition, it is determined whether it is an extreme condition. When the current operating condition is an extreme condition, the upper limit of vehicle speed and total braking force under the current condition are calculated, as well as the motor braking force allocated to the electric motor and the mechanical braking force allocated to the mechanical braking device. When the current speed of the dual-powered vehicle reaches the upper limit of vehicle speed and the risk index is higher than the risk threshold, braking control is performed. During the braking process of the dual-powered vehicle, extreme operating condition data and control effects are recorded and uploaded to the cloud platform. At the same time, environmental and vehicle parameters continue to be acquired periodically to prepare for braking control under extreme conditions. When the current operating condition is normal, environmental and vehicle parameters continue to be acquired to prepare for braking control under extreme conditions.

[0213] In a specific scenario, the flowchart for regenerative braking is as follows: Figure 5 As shown. Specifically, the total braking force is calculated, the upper limit of the regenerative braking force and the target regenerative ratio are calculated, the electric braking force and mechanical braking force are determined, the electric braking force is reduced when the vehicle shows signs of instability and compensated by the mechanical braking force, the electric braking force is finely adjusted within a safe range to obtain the final electric braking force and mechanical braking force, and the electric braking force is sent to the motor controller and the mechanical braking force is sent to the mechanical braking device controller.

[0214] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0215] Based on the same inventive concept, this application also provides a braking control device for a dual-powered vehicle to implement the braking control method for the dual-powered vehicle described above. The solution provided by this device is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the braking control device for a dual-powered vehicle provided below can be found in the limitations of the braking control method for a dual-powered vehicle described above, and will not be repeated here.

[0216] In one embodiment, a braking control device for a dual-powered vehicle is provided, comprising:

[0217] The risk determination unit is used to determine the risk index of the dual-powered vehicle under the current operating conditions based on the vehicle parameters and the environmental parameters of the current environment.

[0218] The vehicle speed limit determination unit is used to calculate the vehicle speed limit of a dual-powered vehicle under the current operating conditions based on the risk index.

[0219] The deceleration determination unit is used to calculate the first deceleration based on the brake pedal opening and the current vehicle speed of the dual-powered vehicle when the current vehicle speed reaches the speed limit and the risk index is higher than the risk threshold, and to calculate the second deceleration based on the current vehicle speed and the speed limit.

[0220] The total braking force determination unit is used to calculate the total braking force required for the deceleration of a dual-powered vehicle based on the maximum value of the first deceleration and the second deceleration.

[0221] The braking control unit is used to control the braking of a dual-powered vehicle using total braking force.

[0222] The various modules in the braking control device of the aforementioned dual-powered vehicle can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0223] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0224] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0225] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0226] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0227] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0228] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A braking control method for a dual-powered vehicle, characterized in that, The method includes: S1. Determine the risk index of the dual-source power supply vehicle under the current operating conditions based on the vehicle parameters and the environmental parameters of the current environment. S2. Based on the risk index, calculate the maximum speed of the dual-source power supply vehicle under the current operating conditions; S3. Calculate the first deceleration based on the brake pedal opening and the current vehicle speed of the dual-powered vehicle, and calculate the second deceleration based on the current vehicle speed and the upper limit of vehicle speed. S4. Calculate the total braking force required for the dual-source power supply vehicle to decelerate based on the maximum value of the first deceleration and the second deceleration; S5. When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, the dual-powered vehicle is braked by the total braking force.

2. The method according to claim 1, characterized in that, Step S5 includes: Based on the distances between the center of mass of the dual-powered vehicle and the front and rear axles of the dual-powered vehicle, the normal loads of the front and rear axles are calculated. Based on the front axle normal load and the road adhesion coefficient of the current driving surface, calculate the maximum available braking force of the front axle; based on the rear axle normal load and the road adhesion coefficient, calculate the maximum available braking force of the rear axle. Based on the aforementioned front axle normal load F z,f and the rear axle normal load F z,r Through formula Calculate the first front axle distribution ratio ; Based on the total braking force F brk,rep and the first front axle allocation ratio ,pass and Calculate the first candidate braking force allocated to the front axle from the total braking force. and the second candidate braking force allocated to the rear axle ; The minimum value between the first candidate braking force and the maximum available braking force of the front axle is determined as the first front axle braking force to be allocated to the front axle; the total braking force minus the first front axle braking force is calculated; the minimum value between the subtraction result and the maximum available braking force of the rear axle is determined as the first rear axle braking force to be allocated to the rear axle. When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on the first front axle braking force and the first rear axle braking force.

3. The method according to claim 2, characterized in that, The method further includes: If based on the first front axle braking force F x,f1 and the first rear axle braking force F x,r1 When braking control is applied to the dual-powered vehicle, if the vehicle speed cannot be reduced to the recommended speed range or the dual-powered vehicle cannot drive stably, then... Calculate the second front axle distribution ratio ; Based on the second front axle distribution ratio, calculate the second front axle braking force distributed to the front axle and the second rear axle braking force distributed to the rear axle in the total braking force; When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on the second front axle braking force and the second rear axle braking force.

4. The method according to claim 1, characterized in that, Step S5 includes: Based on the vehicle parameters, the state parameters of the motor in the dual-source power supply vehicle, and the road surface adhesion coefficient of the current driving surface, the upper limit of the regenerative braking force of the motor is determined; based on the risk index and the state parameters of the motor, the target regenerative ratio is determined. Based on the upper limit of regenerative braking force and the target regenerative ratio, determine the motor power required to be provided by the motor and the mechanical braking force required to be provided by the mechanical braking device in the dual-source power supply vehicle in the total braking force. When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, braking control is applied to the dual-powered vehicle based on the electric motor force and the mechanical braking force.

5. The method according to claim 4, characterized in that, The calculation process for the upper limit of the regenerative braking force includes: The upper limit of the regenerative torque of the motor is determined based on the current temperature and current speed of the motor, the system status of the dual-source power supply vehicle, and the DC circuit voltage between the motor and the battery of the dual-source power supply vehicle. Based on the upper limit of regenerative torque The wheel radius R of the dual-source power supply vehicle w Transmission efficiency The overall speed ratio i is obtained through... Calculate the upper limit F of the wheel axial force of the dual-source powered vehicle. m,lim Determine the upper limit of the maximum regenerative braking force, the upper limit of the available longitudinal force for drive shaft attachment, and the upper limit of the global safety limiting force for the dual-source power supply vehicle. The minimum value among the upper limit of the wheel axial force, the upper limit of the maximum regenerative braking force, the upper limit of the available longitudinal force for drive shaft attachment, and the upper limit of the global safety limiting force is determined as the upper limit of the regenerative braking force.

6. The method according to claim 4, characterized in that, The calculation process for the target regeneration ratio includes: Based on the battery status of the dual-powered vehicle, its connection status with the external power grid, and the downhill slope index in the risk indicators of the dual-powered vehicle, an initial proportion is determined; based on the maximum value R in the risk index, through... Determine the correction factor f for the initial proportion risk ; f is the first preset value. min f is the preset lower cutoff limit. max `clip` is the preset upper limit for truncation; `clip` is the truncation function. When the total braking force is greater than the second preset value, the ratio of the upper limit of the regenerative braking force to the total braking force is determined as the first candidate percentage; the product of the initial percentage and the correction coefficient is determined as the second candidate percentage. The minimum value between the first candidate percentage and the second candidate percentage is determined as the target regeneration percentage.

7. The method according to claim 4, characterized in that, The method further includes: Based on the electric motor power And the current vehicle speed v, through Calculate the first candidate regeneration power The minimum value among the upper limit of motor regenerative power, upper limit of absorption capacity, upper limit of DC bus voltage constraint power, upper limit of stability power constraint power and preset safety upper limit is the second candidate regenerative power. The minimum value between the candidate regenerative power and the second candidate regenerative power is determined as the desired regenerative power of the motor, so as to perform braking control based on the desired regenerative power.

8. The method according to claim 1, characterized in that, The calculation process of the longitudinal risk index in the risk index mentioned in step S1 includes: Based on the maximum permissible deceleration of the dual-powered vehicle on the current road surface. The acceleration a caused by the slope grade and the expected deceleration a req1 ,pass Calculate the deceleration margin of the dual-powered vehicle; based on the deceleration margin M dec ,pass Obtain the deceleration margin sub-risk r dec risk is a mapping function; Based on the current vehicle speed v and the preset safe vehicle speed v of the dual-source power supply vehicle safe ,pass Obtaining the risk of hypervelocities r spd ; Based on the current temperature T of the braking system of the dual-powered vehicle b and temperature threshold T warn ,pass Obtaining thermal decay risk r heat ; Based on the weighted summation of the deceleration margin sub-risk, the overspeed sub-risk, and the thermal decay sub-risk, the longitudinal risk index in the risk index is determined, and the vehicle speed limit is calculated using the longitudinal risk index.

9. The method according to claim 8, characterized in that, The calculation of the vehicle speed limit using the longitudinal risk index includes: Obtain the reference speed limit of the current driving road surface; Based on the aforementioned benchmark speed limit v base and the longitudinal risk index R v ,pass The maximum speed v of the dual-source powered vehicle under the current operating conditions is obtained. max K v These are calibration coefficients.

10. The method according to claim 9, characterized in that, Step S5 includes: Obtain the preset speed margin and the lower limit of the recommended speed range for the dual-source powered vehicle on the current road surface; The result of subtracting the speed margin from the upper limit of vehicle speed is determined as the upper limit of the recommended vehicle speed range; When the current speed of the dual-powered vehicle reaches the speed limit and the risk index is higher than the risk threshold, the total braking force is used to brake the dual-powered vehicle so that the speed of the dual-powered vehicle is within the recommended speed range.

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