Self-adaptive cruise control method and system, vehicle and storage medium

Abstract

The invention relates to the technical field of vehicle control, and discloses a self-adaptive cruise control method and system, a vehicle and a storage medium which are applied to a pure electric vehicle, and the method comprises the steps that according to driving state information of a front target vehicle and dynamic parameters of the vehicle, the target deceleration of the vehicle is determined in combination with a safe vehicle following distance model; when it is judged that the pure electric braking condition is not met based on the relation between the target deceleration and the braking force threshold value of the electric braking system and in combination with the real-time battery state of the vehicle, a cooperative braking mode is started; in the cooperative braking mode, the electric braking system is controlled to provide regenerative braking force, and a cooperative braking instruction is sent to the electronic stability control system, so that the electronic stability control system provides mechanical braking force for cooperative braking; the electronic stability control system further adjusts mechanical braking force distribution of all wheels of the vehicle based on the vehicle wheel speed and the vehicle body posture parameters so as to maintain stable running of the vehicle.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to an adaptive cruise control method, system, vehicle, and storage medium. Background Technology

[0002] With the increasing intelligence of pure electric light trucks, the demand for adaptive cruise control (ACC) is growing. Current ACC systems often employ a simple combination of electric motor braking and hydraulic / pneumatic braking, with braking force distribution relying on independent decisions from the vehicle controller, failing to fully integrate vehicle dynamic control capabilities. This approach suffers from poor braking coordination, premature or delayed mechanical braking intervention, and low energy recovery efficiency. Under complex conditions, the lack of real-time perception and response to vehicle attitude often leads to risks such as wheel lock-up and yaw instability during braking, affecting driving safety and comfort. Furthermore, existing electronic stability control (ESC) systems are mostly used as passive safety modules and do not participate in the coordinated control of ACC, resulting in low system integration and high response latency. Summary of the Invention

[0003] In view of this, embodiments of this application provide an adaptive cruise control method, system, vehicle, and storage medium, which can effectively solve the problems of poor braking coordination, insufficient driving stability, low energy recovery efficiency, and high system response delay in the ACC function of pure electric vehicles in the prior art, thereby achieving safe, comfortable, and fast-responding intelligent following control.

[0004] In a first aspect, an adaptive cruise control method according to an embodiment of this application, applied to a pure electric vehicle, includes: Based on the driving status information of the target vehicle ahead and the dynamic parameters of the vehicle itself, combined with the safe following distance model, the target deceleration of the vehicle is determined. When the pure electric braking conditions are not met based on the relationship between the target deceleration and the braking force threshold of the electric braking system, and combined with the real-time battery status of the vehicle, the vehicle enters the cooperative braking mode. In the cooperative braking mode, the electric braking system is controlled to provide regenerative braking force and send a cooperative braking command to the electronic stability control system, so that the electronic stability control system provides mechanical braking force for cooperative braking; wherein, the electronic stability control system also adjusts the distribution of mechanical braking force to each wheel of the vehicle based on the vehicle wheel speed and vehicle attitude parameters, so as to maintain the stable driving of the vehicle.

[0005] In an optional implementation, the safe following distance model consists of a basic safe distance, the vehicle's speed, a reaction time coefficient, and a road surface adhesion coefficient compensation value. The road surface adhesion coefficient compensation value is determined based on the vehicle kinematic characteristic parameters collected by the electronic stability control system.

[0006] In an optional implementation, the driving status information of the target vehicle ahead includes the speed of the target vehicle ahead, the relative distance between the target vehicle and the vehicle, and the relative acceleration between the target vehicle and the vehicle; the dynamic parameters of the vehicle include the vehicle's driving speed. The step of determining the vehicle's target deceleration based on the driving status information of the target vehicle ahead and the vehicle's dynamic parameters, combined with a safe following distance model, includes: The basic safety distance is determined based on the preset expected vehicle speed and following distance level; The response delay compensation distance is determined based on the current vehicle speed and the reaction time coefficient. The safe following distance is determined based on the basic safety distance, the response delay compensation distance, and the road surface adhesion coefficient compensation value. When the relative distance between the vehicle and the target vehicle ahead is less than the safe following distance, the target deceleration required for smooth following is determined based on the relative speed and relative acceleration to predict the movement trend of the target vehicle ahead and the vehicle's speed.

[0007] In an optional implementation, determining whether the pure electric braking conditions are met based on the relationship between the target deceleration and the braking force threshold of the electric braking system, combined with the real-time battery status of the vehicle, includes: When the target deceleration is less than or equal to the maximum available deceleration of the electric braking system under the current operating conditions, and the battery state of charge is lower than the preset charge threshold and the battery temperature is within the allowable operating range, the pure electric braking condition is determined to be met; otherwise, the pure electric braking condition is determined not to be met. The maximum available deceleration of the electric braking system is dynamically determined based on the motor speed, torque capacity, and the maximum allowable charging power fed back by the battery management system.

[0008] In an optional implementation, the vehicle attitude parameters include yaw rate; The electronic stability control system adjusts the distribution of mechanical braking force to each wheel of the vehicle based on the vehicle's wheel speed and vehicle attitude parameters to maintain stable driving, including: The electronic stability control system monitors the wheel speed change rate of each wheel in real time. When the wheel speed change rate of any wheel reaches a preset change threshold and meets the preset lock-up trend judgment condition, the mechanical braking force corresponding to the current wheel is reduced. At the same time, the braking force difference between the left and right wheels is adjusted according to the yaw rate deviation to make the vehicle drive stably.

[0009] In an optional implementation, the method further includes: during the driving of the vehicle, if it is detected that the driver operates the brake pedal, accelerator pedal, or steering angle exceeding a preset threshold, the cooperative braking is stopped.

[0010] Secondly, embodiments of this application provide an adaptive cruise control system, comprising: The calculation module is used to determine the target deceleration of the vehicle based on the driving status information of the target vehicle ahead and the dynamic parameters of the vehicle itself, combined with the safe following distance model. The mode determination module is used to enter the cooperative braking mode when the pure electric braking conditions are not met, based on the relationship between the target deceleration and the braking force threshold of the electric braking system and combined with the real-time battery status of the vehicle. The cooperative control module is used to control the electric braking system to provide regenerative braking force in the cooperative braking mode, and to send a cooperative braking command to the electronic stability control system so that the electronic stability control system provides mechanical braking force for cooperative braking; wherein, the electronic stability control system also adjusts the distribution of mechanical braking force to each wheel of the vehicle based on the vehicle wheel speed and vehicle body posture parameters to maintain the stable driving of the vehicle.

[0011] In an optional implementation, the system further includes an information acquisition module; The information acquisition module is used to acquire the driving status information of the target vehicle ahead, the dynamic parameters of the vehicle, and the battery status information of the vehicle.

[0012] Thirdly, embodiments of this application provide a vehicle that includes the aforementioned adaptive cruise control system.

[0013] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed on a processor, implements the aforementioned adaptive cruise control method.

[0014] The embodiments of this application have the following beneficial effects: By deeply integrating the electronic stability control system into the braking execution of adaptive cruise control, this application achieves efficient coordination between electric braking and mechanical braking, significantly improving energy recovery efficiency while ensuring driving safety. This application fully utilizes the high-precision perception capability of the electronic stability control system of vehicle attitude, and adjusts the distribution of mechanical braking force to each wheel in real time by combining dynamic parameters such as wheel speed and yaw rate. This effectively avoids problems such as wheel lock-up, loss of steering control, and vehicle instability that are prone to occur in traditional adaptive cruise control systems during emergency deceleration or on low-traction surfaces, greatly improving driving stability and comfort under complex conditions. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of an adaptive cruise control system according to an embodiment of this application is shown; Figure 2 A first flowchart of the adaptive cruise control method according to an embodiment of this application is shown; Figure 3 A second flowchart of the adaptive cruise control method according to an embodiment of this application is shown. Detailed Implementation

[0017] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0018] The components of the embodiments of this application described and illustrated in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0019] In the following text, the terms "comprising," "having," and their cognates, which may be used in various embodiments of this application, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more combinations thereof. Furthermore, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0020] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be construed as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0021] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0022] The adaptive cruise control system will be described below with reference to some specific embodiments.

[0023] Figure 1 A schematic diagram of an adaptive cruise control system according to an embodiment of this application is shown. This adaptive cruise control system is applied to pure electric vehicles, and is particularly suitable for pure electric light trucks with the ability to coordinate electronic stability control and electric drive systems. The system includes a computing module 100, a mode judgment module 200, a cooperative control module 300, and an information acquisition module 400. The modules interact with each other via an onboard CAN bus.

[0024] The information acquisition module 400 is used to acquire the driving status information of the target vehicle ahead, the vehicle's dynamic parameters, and the vehicle's battery status information. This module includes a millimeter-wave radar sensor installed at the front of the vehicle, attitude sensors (such as lateral acceleration sensors and yaw rate sensors) integrated into the electronic stability control system, wheel speed sensors, and status signals from the battery management system. Specifically, the millimeter-wave radar is responsible for acquiring information such as the speed, relative distance, and relative acceleration of the target vehicle ahead; the attitude sensors and wheel speed sensors are used to acquire the vehicle's dynamic parameters, including but not limited to the current driving speed and vehicle motion status; and the battery management system provides information such as the state of charge, temperature, and maximum allowable charging power of the power battery.

[0025] The calculation module 100 is used to determine the target deceleration of the vehicle based on the driving status information of the target vehicle ahead and the dynamic parameters of the vehicle itself, combined with a safe following distance model. This module runs in the ACC control unit, and its calculation logic comprehensively considers factors such as the driver's desired speed, following distance level, real-time relative motion relationship, and road adhesion conditions to output a continuously adjustable target deceleration value, providing an input basis for subsequent braking decisions. The mode determination module 200 is used to determine, based on the relationship between the target deceleration output by the calculation module 100 and the braking force threshold of the electric braking system, and combined with the real-time battery status information of the vehicle, if the pure electric braking conditions are not met, to enter the cooperative braking mode; specifically, if the target deceleration does not exceed the capability range of the electric braking system, and the battery SOC is within the allowable range and the temperature is normal, then the pure electric braking mode is entered; otherwise, it is determined that the cooperative braking mode needs to be activated.

[0026] The cooperative control module 300, in cooperative braking mode, controls the electric braking system to provide regenerative braking force and sends a cooperative braking command to the electronic stability control system, so that the electronic stability control system provides mechanical braking force for cooperative braking. It can be understood that the cooperative control module 300 is activated after determining that cooperative braking mode has been entered; its main function is to send a cooperative braking command to the electronic stability control system, based on prioritizing regenerative braking, to coordinate the timing and magnitude of mechanical braking intervention. Upon receiving this command, the electronic stability control system dynamically adjusts the distribution of mechanical braking force to each wheel according to the current wheel speed change trend, yaw rate deviation, and other vehicle attitude parameters, preventing wheel lock-up or vehicle instability caused by uneven braking force, thereby ensuring that the vehicle maintains good driving stability during deceleration.

[0027] All of the above modules are deployed on the vehicle controller platform or a distributed ECU network. The information acquisition module 400 is connected to physical devices via sensor interfaces. The calculation module 100, the mode determination module 200, and the cooperative control module 300 together constitute the adaptive cruise control unit (ACC control unit). This ACC control unit is deployed as a functional entity in the vehicle controller (VCU) or a separate ADAS control unit and exchanges data with other subsystems via the standard CAN communication protocol. The cooperative control module 300 has a dedicated message channel with the electronic stability control system to ensure that cooperative braking commands can be delivered and executed quickly.

[0028] Figure 2 A schematic flowchart of an adaptive cruise control method according to an embodiment of this application is shown. Exemplarily, this adaptive cruise control method is executed based on the aforementioned adaptive cruise system and includes steps S100-S300: Step S100: Based on the driving status information of the target vehicle ahead and the dynamic parameters of the vehicle itself, combined with the safe following distance model, determine the target deceleration of the vehicle itself.

[0029] Exemplary, the safe following distance model comprises a base safe distance, the vehicle's speed, a reaction time coefficient, and a road surface adhesion coefficient compensation value. This model is not set with a fixed time or distance, but rather dynamically adjusted based on actual traffic conditions and vehicle status, thereby improving adaptability and safety under different operating conditions. The road surface adhesion coefficient compensation value is determined based on the vehicle's kinematic characteristics parameters collected by the electronic stability control system. These parameters include, but are not limited to, lateral acceleration, yaw rate, and wheel speed difference, reflecting the friction characteristics of the current road surface and the vehicle's attitude stability. For example, when the system detects large fluctuations in yaw rate and significant differences in wheel speed between the left and right sides, it can infer that the vehicle is on a low-adhesion road surface (such as rain, snow, or slippery sections). In this case, the road surface adhesion coefficient compensation value is automatically increased, extending the safe following distance and initiating deceleration preparation in advance to avoid the risk of rear-end collisions due to insufficient braking response.

[0030] In this embodiment, the driving status information of the target vehicle ahead can be obtained through a millimeter-wave radar sensor, mainly including the speed of the target vehicle ahead, the relative distance between it and the vehicle, and the relative acceleration between it and the vehicle; the dynamic parameters of the vehicle are derived from the vehicle speed signal provided by the electronic stability control system.

[0031] Specifically, such as Figure 3 As shown, step S100 includes steps S110-S140: Step S110: Determine the basic safety distance based on the preset expected vehicle speed and following distance level.

[0032] In this step, the desired speed and following distance level are both set by the driver. Specifically, the driver can set the desired cruise speed (e.g., adjustable from 30 km / h to 100 km / h) through the function buttons on the instrument panel, and select the following distance level. The following distance level can be divided into three levels: close distance (corresponding to a distance of about 1.5 seconds), medium distance (about 2.0 seconds), and long distance (about 2.5 seconds). The system calculates the corresponding basic safe distance based on the selected level.

[0033] Taking a desired speed of 60 km / h as an example, if the medium-distance mode is selected, the basic safe distance is approximately: Therefore, 33.3 can be used as a basic reference standard for safe following.

[0034] Step S120: Determine the response delay compensation distance based on the current vehicle speed and reaction time coefficient.

[0035] It is understandable that this response delay compensation distance is mainly used to compensate for the time delay between the system sensing changes in the vehicle ahead and the actual control action, including but not limited to sensor sampling period, communication transmission time, and controller processing time.

[0036] The reaction time coefficient can be set as needed, typically between 0.8 and 1.5 seconds. For example, it can be set to 1 second. If set to 1 second, the response delay compensation distance when the vehicle is traveling at 60 km / h is: Then the This distance can be used as a response delay compensation distance under this operating condition.

[0037] Step S130: Determine the safe following distance based on the basic safety distance, response delay compensation distance, and road surface adhesion coefficient compensation value.

[0038] As previously shown, the road surface adhesion coefficient compensation value is dynamically adjusted according to road conditions. It is expressed in units of length and is used to extend the braking lead time, ensuring sufficient deceleration space under low adhesion conditions. For example, on dry asphalt roads, the compensation value can be set to 0-1 meter; while on icy or snowy roads or in heavy rain, after the system detects abnormal fluctuations in yaw rate or sudden increases in wheel speed difference, it determines that the adhesion coefficient is below 0.4. At this time, the compensation value is adjusted to 3-5 meters to enhance the braking lead time. Taking the aforementioned 60km / h as an example, assuming the basic safe distance is 33.3m, the response delay compensation distance is 16.7m, and the compensation value is 3m, then the final safe following distance is: 33.3 + 16.7 + 3 = 53m.

[0039] Step S140: When the relative distance between the vehicle and the target vehicle ahead is less than the safe following distance, the target deceleration required to achieve smooth following is determined based on the relative speed and relative acceleration to predict the movement trend of the target vehicle ahead and the vehicle's speed.

[0040] In this step, when the actual relative distance between the vehicle and the target vehicle ahead is less than the calculated safe following distance, the system determines that deceleration adjustment is necessary. At this time, the ACC control unit will combine the current relative speed and relative acceleration to predict the movement trend of the target vehicle ahead and determine the target deceleration required for smooth following. Specifically, if the vehicle ahead begins to decelerate (relative acceleration is negative), and the vehicle's approach speed is relatively high, the system initiates the deceleration procedure. For example, if the current vehicle speed is 60 km / h, and the vehicle ahead's speed decreases from 60 km / h to 40 km / h, the relative distance shortens from 30m to 20m, which is lower than the calculated safe distance (assumed to be 25.3m). In this case, the ACC control unit will comprehensively consider factors such as relative deceleration and distance decay rate. The calculation module uses a longitudinal speed adjustment algorithm based on feedforward-feedback composite control, where the relative distance and relative speed of the vehicle ahead are used as feedback, and the relative acceleration of the vehicle ahead is used as feedforward, to comprehensively calculate and generate the target deceleration. The algorithm incorporates comfort constraints, limiting the maximum deceleration to no more than 0.3g and the absolute value of the rate of change of deceleration to no more than 2.5. In the example operating condition, when the system determines that deceleration adjustment is required, the target output deceleration is 0.2g (approximately 2...). This can effectively shorten the following distance while ensuring driving comfort.

[0041] In step S200, based on the relationship between the target deceleration and the braking force threshold of the electric braking system, and combined with the real-time battery status of the vehicle, if it is determined that the pure electric braking conditions are not met, the vehicle enters the cooperative braking mode.

[0042] This step is mainly used to rationally allocate braking force sources. Under the premise of ensuring braking performance, the electric drive system is given priority to realize energy recovery, and mechanical braking is introduced only when necessary as a supplement, thereby achieving a balance between energy saving, safety and comfort.

[0043] The maximum available deceleration of the electric braking system is dynamically determined based on the motor speed, torque capacity, and the maximum allowable charging power fed back by the battery management system.

[0044] In this embodiment, whether to activate pure electric braking is not determined solely by the target deceleration magnitude, but rather by a combination of multiple parameters, including but not limited to electric braking capability matching, power battery acceptability, and vehicle operating condition adaptability.

[0045] As an example, the method for determining whether the pure electric braking conditions are met is as follows: if the target deceleration is less than or equal to the maximum available deceleration of the electric braking system under the current operating conditions, and the state of charge of the power battery is below a preset charge threshold and the battery temperature is within the allowable operating range, then the pure electric braking conditions are met; otherwise, the conditions are not met, and the system needs to switch to cooperative braking mode. This logic can be executed by the mode determination module of the ACC control unit, with a determination cycle of once every 50 milliseconds, ensuring timely response and continuous control.

[0046] Furthermore, the maximum available deceleration of the electric braking system is not a fixed value, but is calculated in real time based on the motor speed, output torque capability, and the maximum permissible charging power fed back by the battery management system. This is because the braking force provided by regenerative braking is limited by several physical boundary conditions, mainly including two aspects: motor-side capability and battery-side limitations.

[0047] From the perspective of the motor, the power generation capacity of a permanent magnet synchronous drive motor varies across different speed ranges. For example, at low speeds (below 30 km / h), the back electromotive force is low, limiting the output of regenerative torque; while at high speeds (above 80 km / h), as the motor speed increases, the back electromotive force increases, potentially causing the bus voltage to exceed limits, thus forcing a reduction in regenerative power. Therefore, the motor controller feeds back the maximum regenerative braking torque currently available to the ACC control unit based on the current motor speed, cooling status, and maximum output negative torque; the ACC control unit, combined with parameters such as the transmission ratio and tire rolling radius, converts this into the maximum usable deceleration value at the vehicle level. Taking a certain model of light truck as an example, its drive motor can provide a stable regenerative deceleration of approximately 0.3g at a vehicle speed of 60 km / h; however, when the vehicle speed increases to 90 km / h, due to the high-voltage system approaching its voltage limit, the motor controller actively derated the output, at which point the maximum usable deceleration drops to approximately 0.18g.

[0048] From the battery perspective, the Battery Management System (BMS) continuously monitors the operating status of the power battery and provides key data to the ACC control unit, including the current SOC value, battery temperature, and maximum allowable charging power. These parameters directly affect whether the system can safely receive regenerative energy. In this embodiment, the preset charge threshold can be set to 90%, meaning that when the battery's state of charge reaches or exceeds 90%, the battery is considered close to a fully charged state. To prevent overcharging risks, the system will limit or even disable the electric braking function. Furthermore, battery temperature also constitutes an important constraint, with the allowable operating range set to -10℃ to 55℃. If the battery temperature is detected to exceed this range (e.g., during low-temperature winter starts or prolonged high-load charging leading to excessive temperature rise), the electric braking function will be temporarily disabled to avoid battery damage.

[0049] Furthermore, the BMS will also report the maximum allowable charging power in real time. This value gradually decreases as the State of Charge (SOC) increases. For example, at an SOC of 65%, the maximum allowable charging power is 40kW; however, when the SOC rises above 85%, this value may drop below 15kW. The ACC control unit will adjust the actual available capacity of the electric braking system accordingly.

[0050] It is understandable that the pure electric braking condition is only ultimately determined to be met if the target deceleration does not exceed the maximum available deceleration calculated dynamically above, the battery SOC has not reached its upper limit, the temperature is within the normal range, and the allowable charging power is sufficient. If any of these conditions are not met, the system determines that the pure electric braking condition is not met and triggers the subsequent coordinated braking process.

[0051] For example, in one scenario, the vehicle in front brakes suddenly. The system calculates the required target deceleration as 0.4g, but the electric braking system can only provide a maximum deceleration of 0.3g (affected by the reduced power generation capacity of the motor in the high-speed range). The remaining 0.1g must be supplemented by mechanical braking. Even though the battery is in good condition, the insufficient electric braking capacity necessitates entering a coordinated braking mode. Another example is during afternoon operation in summer, when the battery SOC reaches 92%. Although the target deceleration is only 0.25g, theoretically, the motor braking could cover it. However, because the BMS prohibits energy recovery, the system can only activate mechanical braking in advance to participate in deceleration. Yet another example is during continuous braking on a long downhill slope. Prolonged operation of the electric brake may cause the motor or controller to overheat. The system actively reduces its maximum available deceleration to below 0.1g, which is insufficient to meet the following requirements, necessitating ESC intervention to supplement the braking force.

[0052] Once any of the above situations occur, the ACC control unit immediately generates a coordinated braking command and sends it to the electronic stability control system via the vehicle CAN bus, officially initiating the joint control process of electric braking and mechanical braking.

[0053] In step S300, under the cooperative braking mode, the electric braking system is controlled to provide regenerative braking force, and a cooperative braking command is sent to the electronic stability control system so that the electronic stability control system provides mechanical braking force for cooperative braking.

[0054] In this embodiment, when the system determines that the conditions for pure electric braking are not met, the ACC control unit immediately activates the cooperative control strategy. First, the electric braking system is prioritized to handle all regenerative braking force output within its capacity. Specifically, the ACC control unit sends a braking torque request to the motor controller, driving the permanent magnet synchronous motor to operate in generator mode. This generates negative torque through the anti-trailer wheel, achieving vehicle deceleration while converting kinetic energy into electrical energy to be fed back to the power battery, thereby improving the overall vehicle energy utilization efficiency. Simultaneously, the ACC control unit sends a cooperative braking command to the Electronic Stability Control (ESC) system via the vehicle's CAN bus. This command includes the total amount of supplementary mechanical braking force, the target deceleration value, and the current vehicle operating status information. Upon receiving the command, the ESC activates the hydraulic modulation unit, controlling the brake calipers of each wheel to apply corresponding pressure to supplement the remaining braking force demand that the electric braking system fails to cover.

[0055] It should be noted that the electronic stability control system in this embodiment is not merely a passive terminal module for executing mechanical braking, but a key component that actively participates in maintaining vehicle stability. It can dynamically adjust the distribution of mechanical braking force to each wheel based on its own wheel speed and vehicle attitude parameters, ensuring that the vehicle maintains stable driving even under complex conditions.

[0056] Among these, the vehicle attitude parameters include at least the yaw rate, which is collected in real time by the gyroscope integrated within the ESC and updated every 10 milliseconds. The yaw rate reflects the vehicle's tendency to rotate around its vertical axis and is an important basis for judging whether there is a risk of fishtailing or understeer.

[0057] In some implementations, the electronic stability control system (ESC) achieves fine-tuning of the mechanical braking force of each wheel through the following mechanism: the system continuously monitors the wheel speed change rate of each wheel, i.e., the magnitude of wheel speed decrease per unit time. When the wheel speed change rate of a certain wheel reaches a preset threshold (e.g., a wheel speed decrease of more than 15% within 50 milliseconds) and meets preset lock-up trend judgment conditions (e.g., slip ratio exceeding a critical value, sudden acceleration change, etc.), the system determines that the wheel has a risk of lock-up and immediately reduces the mechanical braking force of the corresponding wheel to prevent tire lock-up from causing loss of steering control or skidding. For example, during emergency deceleration while following another vehicle on a wet and slippery road surface, the left front wheel experiences a sudden drop in traction due to local water accumulation, causing a rapid decrease in wheel speed. The ESC detects an abnormally high wheel speed change rate, which meets the lock-up trend judgment logic. It then adjusts the brake fluid pressure of the wheel through a solenoid valve, appropriately releasing the braking force. After the wheel speed recovers, the braking force is gradually applied again to achieve anti-lock braking control (ABS function).

[0058] In addition, the system adjusts the braking force difference between the left and right wheels based on the yaw rate deviation to suppress vehicle yaw and maintain the expected driving trajectory. Yaw rate deviation refers to the difference between the actual measured value and the theoretical expected value, the latter calculated based on steering wheel angle, vehicle speed, and vehicle dynamics model. If the actual yaw rate is detected to be greater than the expected value, indicating oversteer (a tendency to fishtail), the system automatically increases the braking force on the outer wheels or decreases the braking force on the inner wheels to generate a corrective torque. Conversely, if the actual value is less than the expected value, it is considered understeer, and additional braking force can be applied to the outer wheels to enhance the return-to-center effect. For example, when a vehicle is undergoing coordinated braking in a curve, the load on the inner wheels decreases due to centrifugal force, making them prone to premature wheel lock-up. In this case, ESC not only adjusts the braking force of a single wheel based on the wheel speed change rate but also comprehensively judges the vehicle's attitude based on the yaw rate deviation. If the system detects a tendency for the vehicle to deviate outwards (low yaw rate), it appropriately increases the braking force distribution ratio of the outer wheels to form a stable steering torque, helping the vehicle to decelerate smoothly along its original lane.

[0059] The two control actions mentioned above—anti-lock braking adjustment based on wheel speed change rate and yaw stability correction based on yaw rate deviation—are executed in parallel within the same control cycle, together forming a multi-dimensional driving stability assurance mechanism. The entire process is autonomously completed by the electronic stability control system in a closed-loop adjustment, without intervention from the ACC control unit, ensuring response speed and control accuracy.

[0060] It is understood that, through the above methods, this embodiment can achieve efficient coordination between electric braking and mechanical braking during the coordinated braking process, while giving full play to the core role of ESC in vehicle dynamic control, solving the problems of sudden braking force and vehicle instability that are prone to occur in traditional ACC systems under complex road conditions or emergency conditions, thereby improving the safety and comfort of pure electric light truck assisted driving.

[0061] In some implementations, if the driver operates the brake pedal, accelerator pedal, or steering angle exceeding a preset threshold during vehicle operation, the cooperative braking is stopped.

[0062] Specifically, during the operation of the adaptive cruise control function, the system constantly monitors the driver's operating intentions. To ensure the safety and control priority of human-machine co-driving, when the system detects that the driver has actively intervened in the vehicle's operation, it must immediately terminate the automatic control logic and completely return the longitudinal and lateral control of the vehicle to the driver.

[0063] In some implementations, if the system detects that the driver's operation of the brake pedal, accelerator pedal, or steering wheel angle exceeds a preset threshold during vehicle operation, the system immediately stops the coordinated braking and terminates the current ACC control process. This judgment process can be executed in real time by the ACC control unit, whose signal sources include displacement sensors installed on the brake and accelerator pedals, and a steering angle sensor on the steering column. Each trigger condition is judged independently; the exit action is triggered as soon as any one condition is met, without the need for multiple conditions to be met simultaneously.

[0064] When the driver depresses the brake pedal and reaches a certain travel distance (e.g., more than 5% of the total travel), the brake pedal sensor outputs a valid signal. The ACC control unit recognizes this as a clear intention to decelerate, and regardless of the condition of the vehicle ahead, it is considered a driver request to take over braking control. At this point, the system immediately sends a brake release command to the electric braking system and electronic stability control system, clearing all regenerative braking force and cooperative mechanical braking force output, restoring to the normal manual braking mode. Similarly, when the driver depresses the accelerator pedal deeply, for example, with a pedal opening exceeding 20%, or the acceleration request is significantly higher than required by the current following strategy, the system determines it as an intention to overtake or actively accelerate, and immediately exits ACC control, switching to driver-controlled autonomous driving mode. Furthermore, the exit mechanism is also triggered when the steering wheel angle or steering angular velocity exceeds a preset threshold. For example, if the steering wheel angle remains greater than 5°, or the steering angular velocity is greater than 30° / second, the system recognizes that the driver is performing an active steering operation, possibly intending to change lanes or avoid obstacles, and the original lane-following logic is no longer applicable. To prevent the risk of instability due to longitudinal deceleration during steering, the ACC function immediately exits, stopping all automatic braking force distribution.

[0065] The aforementioned exit action has the highest priority. Once triggered, the ACC control unit will not only stop issuing new coordinated braking commands, but will also clear the current following target and display a message on the instrument panel indicating that ACC has exited or a similar status, reminding the driver that they are currently in manual driving mode.

[0066] It should be noted that stopping the coordinated braking does not simply mean turning off the command output, but includes a series of chain operations, including but not limited to the electric drive system exiting the regenerative braking mode and resuming free coasting or requesting driving force output by pressing the accelerator; after receiving the brake release signal, the ESC system gradually releases the hydraulic pressure introduced by the coordinated braking; the control of the vehicle returns to the driver, and the subsequent vehicle behavior is entirely determined by the pedal input and steering operation.

[0067] This embodiment ensures that in any emergency, the driver can quickly regain control of the vehicle through simple and natural operation, avoiding conflicts between automated systems and manual operation, thereby improving the availability and safety of the entire vehicle system.

[0068] This embodiment deeply integrates the electronic stability control system into the braking execution of adaptive cruise control, achieving efficient coordination between electric and mechanical braking. This effectively improves energy recovery efficiency while ensuring driving safety. This embodiment fully utilizes the high-precision perception of vehicle attitude by the electronic stability control system, combining dynamic parameters such as wheel speed and yaw rate to adjust the distribution of mechanical braking force to each wheel in real time. This effectively avoids problems such as wheel lock-up, loss of steering control, and vehicle instability that easily occur in traditional adaptive cruise control systems during emergency deceleration or on low-traction surfaces, significantly improving driving stability and comfort under complex conditions. Simultaneously, by comprehensively judging multi-dimensional conditions such as target deceleration and battery status, regenerative braking is prioritized for energy recovery, and mechanical braking force is supplemented only when necessary by the electronic stability control system, minimizing friction braking losses and extending the driving range of pure electric vehicles. The entire control process is responsive and logically clear, achieving high-performance combined longitudinal deceleration and lateral stability control without the need for additional dedicated hardware.

[0069] This application also provides a vehicle, exemplary, that includes the aforementioned adaptive cruise control system.

[0070] This vehicle is a pure electric light truck equipped with an adaptive cruise control system, electric drive system, electronic stability control (ESC), battery management system (BMS), and an onboard sensor integration platform. The adaptive cruise control system, as one of the core modules of the vehicle's intelligent driving functions, is deployed in the vehicle control unit (VCU) or a separate ADAS domain controller, and interacts with subsystems such as the motor controller, ESC, BMS, and forward-facing millimeter-wave radar via a high-speed CAN bus. During vehicle operation, when the driver activates the ACC function, the system autonomously determines the target deceleration and executes corresponding braking force distribution strategies based on the motion state of the target vehicle ahead and the vehicle's dynamic parameters. When conditions are met, electric braking is prioritized for deceleration and energy recovery. When the demand exceeds the electric braking capacity or the battery does not allow for energy recovery, a cooperative braking mode is automatically triggered, where the ESC precisely applies mechanical braking force and adjusts the wheel braking force distribution in real time to maintain vehicle stability. Simultaneously, the system continuously monitors the driver's operating intentions. If the system detects that the brake pedal, accelerator pedal, or steering action exceeds a preset threshold, it immediately disengages from automatic control to ensure the safety and control priority of human-machine co-driving. This vehicle not only improves driving comfort in long-distance following and frequent start-stop scenarios in the city, but also extends the actual operating range through efficient energy recovery, making it suitable for intelligent electric transportation needs in typical working conditions such as urban logistics and intercity delivery.

[0071] This application also provides a computer-readable storage medium for storing the computer program used in the aforementioned vehicle. For example, the computer-readable storage medium may include, but is not limited to, various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0072] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that, in alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0073] In addition, the functional modules or units in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0074] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a smartphone, personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0075] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. An adaptive cruise control method, characterized in that, Applied to pure electric vehicles, including: Based on the driving status information of the target vehicle ahead and the dynamic parameters of the vehicle itself, combined with the safe following distance model, the target deceleration of the vehicle is determined. When the pure electric braking conditions are not met based on the relationship between the target deceleration and the braking force threshold of the electric braking system, and combined with the real-time battery status of the vehicle, the vehicle enters the cooperative braking mode. In the cooperative braking mode, the electric braking system is controlled to provide regenerative braking force and send a cooperative braking command to the electronic stability control system, so that the electronic stability control system provides mechanical braking force for cooperative braking; wherein, the electronic stability control system also adjusts the distribution of mechanical braking force to each wheel of the vehicle based on the vehicle wheel speed and vehicle attitude parameters, so as to maintain the stable driving of the vehicle.

2. The adaptive cruise control method according to claim 1, characterized in that, The safe following distance model consists of a basic safe distance, the vehicle's speed, the reaction time coefficient, and the road surface adhesion coefficient compensation value. The road surface adhesion coefficient compensation value is determined based on the vehicle kinematic characteristic parameters collected by the electronic stability control system.

3. The adaptive cruise control method according to claim 2, characterized in that, The driving status information of the target vehicle ahead includes the speed of the target vehicle ahead, the relative distance between the target vehicle and the vehicle ahead, and the relative acceleration between the target vehicle and the vehicle ahead; the dynamic parameters of the vehicle ahead include the vehicle's driving speed. The step of determining the vehicle's target deceleration based on the driving status information of the target vehicle ahead and the vehicle's dynamic parameters, combined with a safe following distance model, includes: The basic safety distance is determined based on the preset expected vehicle speed and following distance level; The response delay compensation distance is determined based on the current vehicle speed and the reaction time coefficient. The safe following distance is determined based on the basic safety distance, the response delay compensation distance, and the road surface adhesion coefficient compensation value. When the relative distance between the vehicle and the target vehicle ahead is less than the safe following distance, the target deceleration required for smooth following is determined based on the predicted motion trend of the target vehicle ahead and the vehicle's speed, according to the relative speed and relative acceleration.

4. The adaptive cruise control method according to claim 1, characterized in that, Based on the relationship between the target deceleration and the braking force threshold of the electric braking system, and combined with the real-time battery status of the vehicle, it is determined whether the pure electric braking conditions are met, including: When the target deceleration is less than or equal to the maximum available deceleration of the electric braking system under the current operating conditions, and the battery state of charge is lower than the preset charge threshold and the battery temperature is within the allowable operating range, the pure electric braking condition is determined to be met; otherwise, the pure electric braking condition is determined not to be met. The maximum available deceleration of the electric braking system is dynamically determined based on the motor speed, torque capacity, and the maximum allowable charging power fed back by the battery management system.

5. The adaptive cruise control method according to claim 1, characterized in that, The vehicle body attitude parameters include yaw rate; The electronic stability control system adjusts the distribution of mechanical braking force to each wheel of the vehicle based on the vehicle's wheel speed and vehicle attitude parameters to maintain stable driving, including: The electronic stability control system monitors the wheel speed change rate of each wheel in real time. When the wheel speed change rate of any wheel reaches a preset change threshold and meets the preset lock-up trend judgment condition, the mechanical braking force corresponding to the current wheel is reduced. At the same time, the braking force difference between the left and right wheels is adjusted according to the yaw rate deviation to make the vehicle drive stably.

6. The adaptive cruise control method according to claim 1, characterized in that, Also includes: If, during the vehicle's operation, the driver operates the brake pedal, accelerator pedal, or the steering angle exceeds a preset threshold, the coordinated braking will cease.

7. An adaptive cruise control system, characterized in that, include: The calculation module is used to determine the target deceleration of the vehicle based on the driving status information of the target vehicle ahead and the dynamic parameters of the vehicle itself, combined with the safe following distance model. The mode determination module is used to enter the cooperative braking mode when the pure electric braking conditions are not met, based on the relationship between the target deceleration and the braking force threshold of the electric braking system and combined with the real-time battery status of the vehicle. The cooperative control module is used to control the electric braking system to provide regenerative braking force in the cooperative braking mode, and to send a cooperative braking command to the electronic stability control system so that the electronic stability control system provides mechanical braking force for cooperative braking; wherein, the electronic stability control system also adjusts the distribution of mechanical braking force to each wheel of the vehicle based on the vehicle wheel speed and vehicle body posture parameters to maintain the stable driving of the vehicle.

8. The adaptive cruise control system according to claim 7, characterized in that, The system also includes an information acquisition module; The information acquisition module is used to acquire the driving status information of the target vehicle ahead, the dynamic parameters of the vehicle, and the battery status information of the vehicle.

9. A vehicle, characterized in that, The vehicle includes the adaptive cruise control system as described in any one of claims 7-8.

10. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed on a processor, implements the adaptive cruise control method according to any one of claims 1-6.

Images