Self-adaptive hill starting auxiliary control method and system and vehicle

Abstract

The invention discloses a self-adaptive hill starting auxiliary control method and system and a vehicle, and relates to the technical field of vehicle control, and the self-adaptive hill starting auxiliary control method comprises the steps that the actual gradient of the current parking road surface of the vehicle, the actual load of the vehicle, the brake pedal opening degree and the accelerator pedal opening degree are obtained; according to the actual load of the vehicle and the friction coefficient of the current parking road surface, an activation slope threshold value is calculated and generated through a dynamic threshold value model; the actual gradient is compared with an activation gradient threshold value, whether the vehicle enters a prevention mode or not is judged, and whether the prevention mode is triggered or not is judged according to the brake pedal opening degree and the accelerator pedal opening degree; in the prevention mode, the vehicle starts on a slope, whether the vehicle slips on the slope or not is detected in real time, if the vehicle slips on the slope is detected, the vehicle enters the emergency mode, stepped supercharging braking is adopted, and EPB redundancy control is activated. Stable starting and safe driving of the vehicle under various ramp conditions can be achieved, and the problems that a traditional ramp auxiliary system is poor in adaptability and unstable in auxiliary effect are effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle control technology, and in particular to an adaptive hill start assist control method, system and vehicle. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] Currently, vehicle hill hold assist systems generally utilize a slope sensor-based trigger mechanism, implementing temporary brake hold via the ESC (Electronic Stability Control) system. The industry generally adheres to the ISO 26262 standard, which uses a fixed slope threshold as the control baseline. Wheel speed sensors and longitudinal acceleration sensors are used to determine the slope's tendency, and braking force is applied based on this determination to assist in brake hold.

[0004] However, existing hill assist systems still have certain limitations: (1) The slope threshold set in existing hill assist systems is usually based on conventional road standards. It is difficult to apply to unconventional road scenarios with large slopes or complex terrain, and the assistance effect is poor. Moreover, road scenarios are diverse, and it is difficult to set a specific slope threshold for all scenarios to improve the assistance effect.

[0005] (2) Existing hill assist strategies mostly apply a fixed braking force, which cannot be dynamically adjusted in real time according to actual conditions. As a result, under different working conditions, the vehicle may still slip significantly when starting, affecting driving safety and comfort. Summary of the Invention

[0006] To address the deficiencies of the above-mentioned prior art, the present invention provides an adaptive hill start assist control method, system, and vehicle. By accurately detecting the slope of the slope in real time and combining information on key dynamic factors such as vehicle load and road friction coefficient, the method adjusts the braking pressure and power output in the assist strategy in real time, thereby achieving smooth starting and safe driving of the vehicle under various slope conditions, effectively solving the problems of poor adaptability and unstable assist effect of traditional hill start assist systems.

[0007] In a first aspect, the present invention provides an adaptive hill start assist control method.

[0008] An adaptive hill start assist control method, comprising: Obtain the actual slope of the vehicle's current parking surface, as well as the vehicle's actual load, brake pedal opening, and accelerator pedal opening; The activation slope threshold is calculated and generated through a dynamic threshold model based on the actual load of the vehicle and the friction coefficient of the current parking road surface; Compare the actual slope with the activation slope threshold to determine whether the vehicle has entered the prevention mode, and determine whether to trigger the prevention mode based on the brake pedal opening and the accelerator pedal opening; In prevention mode, the vehicle starts on a slope and detects in real time whether the vehicle is sliding down the slope. If sliding down is detected, the vehicle enters emergency mode, adopts stepped boost braking and activates EPB redundant control.

[0009] A further technical solution is to calculate and generate the activation slope threshold through a dynamic threshold model, which is: ; in, is the benchmark slope threshold, is the actual vehicle load, , Indicates the air spring pressure, Indicates area, is the vehicle's rated load, Represents the road friction coefficient.

[0010] A further technical solution is to obtain the friction coefficient of the road surface through wheel speed fluctuation spectrum analysis, including: Based on the wheel speed signal of the ABS system, the frequency domain energy of the wheel speed signal is extracted; The frequency domain energy is mapped to the friction coefficient to obtain the friction coefficient value of the road surface.

[0011] According to a further technical solution, in the prevention mode, the pre-boost brake line releases the brake pressure to a set pressure range and automatically maintains the engine speed within the set speed range; Whether to trigger the prevention mode is determined according to the brake pedal opening and the accelerator pedal opening, that is: when it is detected that the brake pedal opening is not greater than the braking threshold and the accelerator pedal opening is not less than the accelerator threshold, the brake pre-boost in the prevention mode is triggered.

[0012] A further technical solution is to detect in real time whether the vehicle is rolling down a slope. If rolling down a slope is detected, the vehicle enters emergency mode, adopts stepped boost braking, and activates EPB redundancy control, including: Determine whether the vehicle is sliding down the slope based on the front and rear wheel speeds of the vehicle; If the vehicle rolls down a slope, the speed at which it rolls down is calculated based on the speed difference between the front and rear wheels. Whether to enter emergency mode is determined based on the sliding speed; when the sliding speed is greater than the set value, the stepped boost braking is activated, and the EPB redundant braking and power system torque compensation are triggered synchronously.

[0013] A further technical solution is that the stepped boost braking is as follows: the basic braking pressure is determined according to the actual slope, the final applied pressure is determined in combination with the compensation gradient, and the pressure is increased at a set rate until the final applied pressure is reached.

[0014] A further technical solution is to release the brake pressure after the vehicle starts on the slope, and during the release process, the release rate is used Pressure is released, and when the wheel speed acceleration is greater than the set wheel speed acceleration value, the remaining pressure is released instantaneously.

[0015] In a second aspect, the present invention provides an adaptive hill start assist control system.

[0016] An adaptive hill start assist control system comprising: A multi-source signal acquisition module is used to obtain the actual slope of the vehicle's current parking surface, as well as the vehicle's actual load, brake pedal opening, and accelerator pedal opening; An activation slope threshold calculation module is used to calculate and generate an activation slope threshold using a dynamic threshold model based on the vehicle's real-time load and the friction coefficient of the current parking road surface; The mode decision and control module is used to compare the actual slope with the activation slope threshold to determine whether the vehicle has entered the prevention mode, and to determine whether the prevention mode is triggered based on the brake pedal opening and the accelerator pedal opening. In the prevention mode, when the vehicle starts on a slope, it detects in real time whether the vehicle is sliding down the slope. If sliding down is detected, the vehicle enters the emergency mode, adopts stepped boost braking and activates the EPB redundant control.

[0017] A further technical solution is to calculate and generate the activation slope threshold through a dynamic threshold model, which is: ; in, is the benchmark slope threshold, is the actual vehicle load, , Indicates the air spring pressure, Indicates area, is the vehicle's rated load, Represents the road friction coefficient.

[0018] In a third aspect, the present invention further provides a vehicle that executes a vehicle torque control method based on slope prediction as proposed in the first aspect, or includes a vehicle torque control system based on slope prediction as proposed in the second aspect.

[0019] One or more of the above technical solutions have the following beneficial effects: The present invention provides an adaptive hill start assist control method, system, and vehicle. By accurately detecting the slope in real time and incorporating information on key dynamic factors such as vehicle load and road friction coefficient, the system adjusts the braking pressure and power output in the assist strategy in real time, achieving smooth starts and safe driving under various slope conditions. This effectively addresses the poor adaptability and unstable assist effects of conventional hill start assist systems. Compared to conventional hill start assist systems, the present invention utilizes multi-sensor signal fusion and intelligent algorithms to dynamically adjust the control strategy in real time based on actual conditions, employing different braking strategies in different modes. This effectively prevents vehicle slippage and skidding during hill starts, improving driving safety and comfort, and enhancing the vehicle's ability to navigate various road conditions. Furthermore, by incorporating information on key dynamic factors such as vehicle load and road friction coefficient, the present invention accurately adapts to various complex slope conditions, providing stable and reliable assist effects on roads with varying gradients, from shallow to steep slopes, and even those with rapidly changing slopes.

[0020] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0022] Figure 1 Schematic diagram of the flow of the adaptive hill start assist control method according to an embodiment of the present invention; Figure 2 Schematic diagram of the structure of the adaptive hill start assist control system according to an embodiment of the present invention.

[0023] Among them, 1. Multi-source signal acquisition module; 2. Activation slope threshold calculation module; 3. Mode decision and control module 3. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed descriptions are exemplary only and are intended to describe specific embodiments and provide further explanation of the present invention, and are not intended to limit the exemplary embodiments according to the present invention. Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0025] Example 1 To address the problems of existing hill start brake assist strategies that are unable to accurately adapt to slopes of different gradients and cannot assist in adjusting braking according to actual conditions, this embodiment proposes an adaptive hill start assist control method based on multi-source signal fusion and intelligent control strategy. By accurately detecting key information such as slope gradient, vehicle load, and road friction coefficient in real time, it automatically and intelligently adjusts brake pressure and power output to achieve precise assistance in vehicle hill start and parking scenarios, ensuring smooth starting and safe driving of the vehicle under various slope conditions, improving the adaptability of hill start assist, and improving the stability of the assistance effect.

[0026] The adaptive hill start assist control method proposed in this embodiment is as follows Figure 1 As shown, the specific steps include: Step S1: Obtain the actual slope of the vehicle's current parking surface, the vehicle's actual load, the brake pedal opening, and the accelerator pedal opening.

[0027] Specifically, the system uses a high-precision MEMS gyroscope, ABS wheel speed sensors, air spring pressure sensors, and brake and accelerator pedal position monitoring modules to synchronously collect multi-sensor data at a 10ms cycle. This allows real-time monitoring of the vehicle's actual road slope, wheel speed, actual load, brake pedal position, and accelerator pedal position. The high-precision MEMS gyroscope improves slope detection accuracy, and the brake and accelerator pedal position signals can be used to predict the driver's starting intention, providing support for subsequent braking assistance.

[0028] Step S2: Generate an activation slope threshold value by calculating the dynamic threshold value model according to the real-time load of the vehicle and the friction coefficient of the current parking road surface.

[0029] Specifically, a Kalman filter algorithm is used to suppress noise on the actual slope signal collected above to obtain a more accurate actual slope value.

[0030] Secondly, the activation slope threshold is calculated by the dynamic threshold model, which can be updated in real time Threshold, the dynamic threshold model is: ; in, is the benchmark slope threshold, which is usually set to 3°; is the actual load of the vehicle, which is detected by the air spring pressure sensor, that is, , Indicates the air spring pressure, Indicates area; is the vehicle's rated load, Indicates the road friction coefficient. For example, when the vehicle has a rated load of 1800 kg, =300kg) dry road surface ( =0.8) condition, =2.8°; while full load ( =500kg) wet road ( =0.3), =1.15°.

[0031] The above-mentioned dynamic threshold model realizes load-road coupling compensation, that is, the threshold on no-load dry roads is increased to reduce false triggering, and the threshold on fully loaded wet roads is lowered to improve sensitivity. By responding to load changes in real time, closed-loop dynamic adjustment can be achieved to ensure the rationality of the safety threshold under different working conditions. The benchmark parameters can be corrected in real time according to actual conditions to form closed-loop control and ensure the effectiveness of braking.

[0032] Furthermore, considering that the wheel speed fluctuation spectrum energy is positively correlated with adhesion, the road friction coefficient can be perceived in real time. To this end, in this embodiment, the road friction coefficient can be obtained by analyzing the wheel speed fluctuation spectrum. That is, based on the wheel speed signal of the ABS system (Anti-Lock Braking System), the frequency domain energy of the wheel speed signal is extracted, which is: ; Then the frequency domain energy is mapped to the friction coefficient as follows: .

[0033] Through the above method, the road friction coefficient can be detected based on the existing ABS wheel speed signal without adding new sensors. In addition, the influence of instantaneous wheel speed noise can be avoided through frequency domain analysis, and the anti-interference ability can be improved. In this way, the friction coefficient of the vehicle's current road surface can be accurately calculated.

[0034] As another implementation, to further ensure the accuracy of road friction coefficient detection, this example also incorporates a machine learning algorithm. This algorithm acquires features such as wheel speed spectrum energy, tire deformation hysteresis angle, infrared reflectivity ratio, and suspension vibration energy. These features are then fed into a pre-trained machine learning model to output the dynamic friction coefficient μ. This fusion calculation and verification of multiple feature data ensures the accuracy of the final friction coefficient calculation.

[0035] Specifically, multi-sensor data from vehicles traveling on different types of roads, such as five typical road types: dry asphalt, wet asphalt, compacted snow, ice, and gravel, is collected, and the actual μ value is simultaneously recorded. The friction coefficient can be inferred by reverse engineering the deceleration when the ABS is triggered. Secondly, a lightweight gradient boosting decision tree (GBDT) is selected as the prediction model. This model uses the aforementioned four-dimensional feature vector as input and the corresponding actual μ value as output. Continuous iterative training is performed to obtain a trained prediction model.

[0036] By introducing multiple sensor data for calculation as described above, multiple data such as deformation hysteresis angle and vibration energy can be used for double verification, thereby reducing the misjudgment rate and improving detection accuracy. Moreover, using this model for prediction can further improve computing efficiency.

[0037] Step S3: Compare the actual slope with the activation slope threshold to determine whether the vehicle enters the prevention mode, and determine whether the prevention mode is triggered based on the brake pedal opening and the accelerator pedal opening.

[0038] Specifically, the current actual slope is compared with the activation slope threshold. If the actual slope is greater than the activation slope threshold, the vehicle enters preventive mode. After determining that preventive mode is appropriate, the brake pedal opening and accelerator pedal opening are used to determine whether to trigger preventive mode. Specifically, if the brake pedal opening is less than or equal to the braking threshold and the accelerator pedal opening is greater than or equal to the accelerator threshold, for example, if the brake pedal opening is ≤15% and the accelerator pedal opening is ≥10%, the brake pre-boost feature of this mode is triggered. In this embodiment, in preventive mode, the brake line is pre-boosted, releasing the brake pressure to a set pressure range and automatically maintaining the engine speed within the set speed range. The set pressure range is set to 0.5-1.2 MPa, and the set speed range is set to 900-1200 rpm.

[0039] As another implementation, when determining whether to trigger the preventive mode, the brake pedal depression rate is incorporated into the judgment based on the brake pedal opening and accelerator pedal opening. This allows for more comprehensive consideration of differences in driver operating habits and avoids false or missed triggering. Specifically, the brake pedal opening, accelerator pedal opening, and brake pedal depression rate are first acquired in real time. A driving style index is then determined based on the brake pedal depression rate. For example, if the style index range is set to [0, 1], where 1 represents aggressive and 0 represents conservative, the driving style index is determined based on the position of the brake pedal depression rate within the set range. The braking and accelerator thresholds are then dynamically adjusted based on the driving style index. When the brake pedal opening is detected to be less than or equal to the braking threshold and the accelerator pedal opening is detected to be greater than or equal to the accelerator threshold, the preventive mode is determined to be triggered, and brake pre-boost is performed.

[0040] The design of the above-mentioned prevention mode defines the mode triggering conditions, which take into account the driver's mainstream operating habits, can accurately identify the driver's starting intention, and can effectively prevent the vehicle from sliding backward when starting on a slope. In this mode, the power-brake system is accurate, ensuring starting torque by maintaining the engine speed, and pre-compression and braking response delay are shortened.

[0041] Step S4: When the vehicle starts on a slope in the prevention mode, the vehicle is detected in real time to see if it is sliding down the slope. If sliding down the slope is detected, the vehicle enters the emergency mode, adopts stepped boost braking, and activates EPB redundancy control.

[0042] On the basis of the above-mentioned prevention mode, this embodiment also proposes a secondary assistance mechanism, that is, when the vehicle starts on a slope, it detects in real time whether the vehicle is sliding down the slope. If sliding down is detected, it enters the emergency mode, adopts stepped boost braking and activates EPB redundancy control.

[0043] Specifically, first determine whether the vehicle is rolling down a slope based on the current driving condition of the vehicle, including: Step S4.1: Determine whether the vehicle is rolling down a slope based on the front and rear wheel speeds. The ABS wheel speed sensors detect the front and rear wheel speeds in real time. If the rear wheel speed exceeds the front wheel speed for a set period of time (e.g., 400ms), the vehicle is determined to be rolling down a slope.

[0044] Step S4.2: If the vehicle rolls down a slope, calculate the rolling speed based on the front and rear wheel speed difference. The wheel speeds detected by the ABS wheel speed sensors are differentially calculated to obtain the longitudinal rolling speed: , where Represents the rear wheel speed, Indicates the front wheel speed, Indicates slope.

[0045] Step S4.3: Determine whether to enter emergency mode based on the slope speed. In this embodiment, when the slope speed is greater than a set value, such as 0.2 m / s, the emergency mode is determined to be entered. At this time, the stepped boost braking is activated, and the EPB redundant braking and power system torque compensation are simultaneously triggered.

[0046] Furthermore, the aforementioned stepped boost braking system involves determining a base brake pressure based on the actual slope, combining it with a compensation gradient to determine the final applied pressure, and increasing the pressure at a set rate until the final applied pressure is reached. For example, the maximum pressure is increased by 20% every 100ms until the final applied pressure is reached. The brake pressure curve is divided into three categories based on the slope: for slopes less than 5°, the base pressure is set at 1.5 MPa and the compensation gradient is 0.2 MPa / °; for slopes between 5° and 15°, the base pressure is set at 2.0 MPa and the compensation gradient is 0.3 MPa / °; and for slopes greater than 15°, the base pressure is set at 2.8 MPa and the compensation gradient is 0.5 MPa / °.

[0047] This embodiment uses the above-mentioned emergency mechanism layered protection strategy to control the adaptive braking pressure according to specific conditions such as the speed of sliding down the slope. For example, when the slope is greater than 15°, the base pressure rises to 2.8MPa, which is an 87% increase compared to a slope of 5°, and can effectively meet the needs of steep slopes.

[0048] Preferably, the boost braking priority can be set according to actual conditions, such as only activating stepped boost braking when the slope speed is less than 0.5 m / s, and prioritizing triggering EPB redundant braking and power system torque compensation when the slope speed is greater than 0.5 m / s.

[0049] As an implementation method, the brake pressure is released after the vehicle starts on a slope. During the release process, the release rate of the brake pressure can be determined according to the accelerator pedal opening and the wheel speed acceleration, that is, the release rate is used. Pressure is released and when the wheel speed accelerates Release the remaining pressure instantly.

[0050] Through the above method, the pressure release rate is bound to the accelerator pedal opening, the pressure is released slowly at low throttle and quickly at high throttle, matching the driver's expectations and achieving decoupling and coordination between driver and vehicle. At the same time, by setting the wheel speed acceleration threshold, premature release causing secondary sliding is prevented, achieving safe pressure release and avoiding power interruption.

[0051] Compared with traditional hill start assist methods, the above method proposed in this embodiment, through multi-sensor signal fusion and intelligent algorithms, dynamically and in real time adjusts the control strategy according to actual conditions, and adopts different braking strategies in different modes, which can effectively avoid the vehicle from slipping and skidding when starting on a slope, improve driving safety and comfort, enhance the vehicle's passability under different road conditions, and can accurately adapt to various complex slope conditions. Whether it is a small slope, a large slope or a road section with frequently changing slopes, it can provide stable and reliable assistance effects, and realize smooth starting and safe driving of the vehicle under various slope conditions.

[0052] Example 2 This embodiment provides an adaptive hill start assist control system, such as Figure 2 As shown, specifically including: Multi-source signal acquisition module 1, used to obtain the actual slope of the vehicle's current parking surface, the vehicle's actual load, the brake pedal opening, and the accelerator pedal opening; An activation slope threshold calculation module 2 is configured to calculate an activation slope threshold using a dynamic threshold model based on the vehicle's real-time load and the friction coefficient of the current parking road surface; Mode decision and control module 3 is used to compare the actual slope with the activation slope threshold to determine whether the vehicle has entered the prevention mode, and to determine whether the prevention mode is triggered based on the brake pedal opening and the accelerator pedal opening. In the prevention mode, when the vehicle starts on a slope, it detects in real time whether the vehicle is sliding down the slope. If sliding down is detected, the vehicle enters the emergency mode, adopts stepped boost braking and activates the EPB redundancy control.

[0053] Specifically, the adaptive hill-start assist control system proposed in this embodiment corresponds to the control method proposed in Example 1. The system architecture consists of a multi-source signal acquisition module, a data processing module (i.e., an activation slope threshold calculation module), and an actuator (i.e., a mode decision and control module). The multi-source signal acquisition module includes a high-precision MEMS gyroscope, ABS wheel speed sensors, an air spring pressure sensor, and brake and accelerator pedal opening monitoring modules, transmitting real-time data to the data processing module via the CAN bus. The data processing module uses a Kalman filter algorithm to suppress noise on the slope signal and calculates the activation slope threshold based on a dynamic threshold model. The activation slope threshold is compared with the actual slope to determine whether the vehicle has entered preventive mode. Based on the hill-start situation, it determines whether the vehicle is rolling down the slope, thereby determining whether the vehicle has entered emergency mode. Different braking strategies are employed in different modes to achieve precise assistance in hill-start and parking scenarios, ensuring smooth starts and safe driving under various slope conditions and improving the adaptability of hill-start assist. Finally, the actuator includes a brake pre-boost pressure control unit, an engine speed control unit, and a redundant EPB control unit, which is used to perform corresponding braking adjustments.

[0054] In this embodiment, the specific control strategy is as follows: upon power-up, the system first initializes, completing sensor zero-point calibration and loading vehicle parameters. During the real-time monitoring phase, the system synchronously collects data from multiple sensors at a 10ms cycle and updates the activation slope threshold in real time via a dynamic threshold calculation module. Based on the relationship between the current actual slope and the activation slope threshold, the system intelligently switches between preventive mode and emergency mode. The current actual slope is compared with the activation slope threshold. If the actual slope exceeds the activation slope threshold, the system enters preventive mode. After determining that preventive mode is appropriate, the system determines whether to trigger the preventive mode based on the brake pedal opening and accelerator pedal opening. Specifically, if the brake pedal opening is less than or equal to the brake threshold and the accelerator pedal opening is greater than or equal to the accelerator threshold, for example, if the brake pedal opening is ≤15% and the accelerator pedal opening is ≥10%, the brake pre-boost in this mode is triggered. In this embodiment, in preventive mode, the brake line is pre-boosted, releasing the brake pressure to a set pressure range and automatically maintaining the engine speed within the set speed range. For example, in preventive mode, the brake pressure is pre-charged and the engine speed is maintained at 1000±50rpm.

[0055] On the basis of the above-mentioned prevention mode, this embodiment also proposes a secondary assistance mechanism, that is, when the vehicle starts on a slope, it detects in real time whether the vehicle is sliding down the slope. If sliding down is detected, it enters the emergency mode, adopts stepped boost braking and activates EPB redundancy control.

[0056] Specifically, first determine whether the vehicle is rolling down a slope based on the current driving condition of the vehicle, including: First, the ABS wheel speed sensors are used to detect the front and rear wheel speeds of the vehicle in real time. If the rear wheel speed exceeds the front wheel speed for a set time (e.g., 400ms), the vehicle is considered to be rolling.

[0057] Secondly, if the vehicle rolls down a slope, the speed at which the slope rolls down is calculated based on the difference in wheel speed between the front and rear wheels. The longitudinal speed at which the slope rolls down is calculated by performing a differential calculation based on the wheel speed detected by the ABS wheel speed sensor: , where Represents the rear wheel speed, Indicates the front wheel speed, Indicates slope.

[0058] Finally, the vehicle determines whether to enter emergency mode based on the slope speed. Specifically, when the slope speed exceeds a set value, such as 0.2 m / s, emergency mode is activated, activating stepped boost braking, which simultaneously triggers EPB redundant braking and powertrain torque compensation to ensure smooth vehicle starts and safe driving. Stepped boost braking involves determining a base brake pressure based on the actual slope, combining it with a compensation gradient to determine the final applied pressure. Pressure is then increased at a set rate until the final applied pressure is reached, for example, by increasing the maximum pressure by 20% every 100 ms. The brake pressure curve is categorized into three types based on slope: for slopes less than 5°, the base pressure is set to 1.5 MPa with a compensation gradient of 0.2 MPa / °; for slopes between 5° and 15°, the base pressure is set to 2.0 MPa with a compensation gradient of 0.3 MPa / °; and for slopes greater than 15°, the base pressure is set to 2.8 MPa with a compensation gradient of 0.5 MPa / °.

[0059] This embodiment uses the above-mentioned emergency mechanism layered protection strategy to perform adaptive braking pressure control according to specific conditions such as the speed of the slope to match the steep slope requirements.

[0060] Preferably, the boost braking priority can be set according to actual conditions, such as only activating stepped boost braking when the slope speed is less than 0.5 m / s, and prioritizing triggering EPB redundant braking and power system torque compensation when the slope speed is greater than 0.5 m / s.

[0061] As an implementation method, the brake pressure is released after the vehicle starts on a slope. During the release process, the release rate of the brake pressure can be determined according to the accelerator pedal opening and the wheel speed acceleration, that is, the release rate is used. Pressure is released and when the wheel speed accelerates In this way, the pressure release rate is tied to the accelerator pedal opening, releasing pressure slowly at low throttle and quickly at high throttle, matching the driver's expectations and achieving decoupling and coordination between driver and vehicle. At the same time, by setting a wheel speed acceleration threshold, premature release, which could lead to secondary rolling, is prevented, achieving safe pressure release and avoiding power interruption.

[0062] Example 3 This embodiment provides a vehicle that executes an adaptive hill start assist control method as proposed in the first embodiment, or includes an adaptive hill start assist control system as proposed in the second embodiment.

[0063] The steps involved in the above embodiments 2 and 3 correspond to those in the method embodiment 1. For the specific implementation methods, please refer to the relevant description part of the embodiment 1.

[0064] Those skilled in the art will appreciate that the modules or steps of the present invention described above can be implemented using a general-purpose computer device. Alternatively, they can be implemented using program code executable by a computing device, which can then be stored in a storage device and executed by the computing device. Alternatively, they can be fabricated into separate integrated circuit modules, or multiple modules or steps can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0065] The above description is only a preferred embodiment of the present invention. Although the specific implementation of the present invention is described in conjunction with the accompanying drawings, it does not limit the scope of protection of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. An adaptive hill start assist control method, characterized in that: include: Obtain the actual slope of the vehicle's current parking surface, as well as the vehicle's actual load, brake pedal opening, and accelerator pedal opening; The activation slope threshold is calculated and generated through a dynamic threshold model based on the actual load of the vehicle and the friction coefficient of the current parking road surface; Compare the actual slope with the activation slope threshold to determine whether the vehicle has entered the prevention mode, and determine whether to trigger the prevention mode based on the brake pedal opening and the accelerator pedal opening; In prevention mode, the vehicle starts on a slope and detects in real time whether the vehicle is sliding down the slope. If sliding down is detected, the vehicle enters emergency mode, adopts stepped boost braking and activates EPB redundant control.

2. The adaptive hill start assist control method according to claim 1, wherein: The activation slope threshold is calculated by the dynamic threshold model and is: ； in, is the benchmark slope threshold, is the actual vehicle load, , Indicates the air spring pressure, Indicates area, is the vehicle's rated load, Represents the road friction coefficient.

3. The adaptive hill start assist control method according to claim 2, wherein: The friction coefficient of the road surface is obtained through wheel speed fluctuation spectrum analysis, including: Based on the wheel speed signal of the ABS system, the frequency domain energy of the wheel speed signal is extracted; The frequency domain energy is mapped to the friction coefficient to obtain the friction coefficient value of the road surface.

4. The adaptive hill start assist control method according to claim 1, wherein: In the prevention mode, the pre-boost brake line releases the brake pressure to a set pressure range and automatically maintains the engine speed within the set speed range; Whether to trigger the prevention mode is determined according to the brake pedal opening and the accelerator pedal opening, that is: when it is detected that the brake pedal opening is not greater than the braking threshold and the accelerator pedal opening is not less than the accelerator threshold, the brake pre-boost in the prevention mode is triggered.

5. The adaptive hill start assist control method according to claim 1, wherein: Real-time detection of vehicle slipping. If slipping is detected, the system enters emergency mode, adopts stepped boost braking and activates EPB redundancy control, including: Determine whether the vehicle is sliding down the slope based on the front and rear wheel speeds of the vehicle; If the vehicle rolls down a slope, the speed at which it rolls down is calculated based on the speed difference between the front and rear wheels. Whether to enter emergency mode is determined based on the sliding speed; when the sliding speed is greater than the set value, the stepped boost braking is activated, and the EPB redundant braking and power system torque compensation are triggered synchronously.

6. The adaptive hill start assist control method according to claim 1, wherein: The step-by-step boost braking method includes: determining a basic braking pressure according to the actual slope, determining a final applied pressure in combination with a compensation gradient, and increasing the pressure at a set rate until the final applied pressure is reached.

7. The adaptive hill start assist control method according to claim 1, wherein: After the vehicle starts on the slope, the brake pressure is released. During the release process, the release rate is used. Pressure is released, and when the wheel speed acceleration is greater than the set wheel speed acceleration value, the remaining pressure is released instantaneously.

8. An adaptive hill start assist control system, characterized in that: include: A multi-source signal acquisition module is used to obtain the actual slope of the vehicle's current parking surface, as well as the vehicle's actual load, brake pedal opening, and accelerator pedal opening; An activation slope threshold calculation module is used to calculate and generate an activation slope threshold using a dynamic threshold model based on the vehicle's real-time load and the friction coefficient of the current parking road surface; A mode decision and control module is used to compare the actual slope with the activation slope threshold to determine whether the vehicle enters the prevention mode, and to determine whether to trigger the prevention mode based on the brake pedal opening and the accelerator pedal opening; In prevention mode, the vehicle starts on a slope and detects in real time whether the vehicle is sliding down the slope. If sliding down is detected, the vehicle enters emergency mode, adopts stepped boost braking and activates EPB redundant control.

9. The adaptive hill start assist control system according to claim 8, wherein: The activation slope threshold is calculated by the dynamic threshold model and is: ； in, is the benchmark slope threshold, is the actual vehicle load, , Indicates the air spring pressure, Indicates area, is the vehicle's rated load, Represents the road friction coefficient.

10. A vehicle, characterized in that: Execute an adaptive hill start assist control method as described in any one of claims 1-7, or include an adaptive hill start assist control system as described in any one of claims 8-9.

Images