Predictive brake pressure adjusting method and system

Abstract

The invention relates to the field of vehicle braking, in particular to a predictive braking pressure adjusting method and system.The method comprises the steps that road information of a road with the preset length in front of a vehicle is obtained, and meanwhile the current vehicle speed of the vehicle is obtained; obtaining a basic target deceleration, and correcting the basic target deceleration based on the gradient sequence to obtain a target deceleration; acquiring a basic target slip rate, and when the curvature in the curvature sequence is greater than a curvature threshold value, correcting the basic target slip rate based on the curvature in the curvature sequence and the current vehicle speed to obtain a target slip rate; and when it is judged that the pre-triggering condition is met according to the road information of the front road, pre-pressurization is conducted at the preset pressurization rate P0, and when the vehicle enters the road section meeting the pre-triggering condition, the brake pressure is adjusted based on the target deceleration and / or the target slip rate. The delay problem of brake pressure adjustment is relieved, and the brake safety and efficiency are improved.

Description

Technical Field

[0001] This application relates to the field of vehicle braking, specifically to a predictive braking pressure regulation method and system. Background Technology

[0002] Traditional electronic braking systems (EBS) primarily adjust braking pressure in real time based on current vehicle state parameters, such as instantaneous wheel speed and vehicle deceleration. This reactive control strategy performs well under smooth road conditions. However, when encountering sudden changes in road gradient or curvature, such as transitioning from an uphill to a flat slope, from a flat slope to a downhill slope, or suddenly entering a curve, the system suffers from inherent response lag because it cannot anticipate changes in road conditions ahead. This lag leads to excessive deceleration during uphill braking, affecting comfort; insufficient braking force during downhill braking, posing a safety risk; and potential loss of lateral stability due to excessive slip ratio during cornering braking.

[0003] With the development of high-precision maps and vehicle-road cooperative technologies, obtaining information on the slope and curvature of the road ahead has become possible. While some existing technologies attempt to utilize future road information for vehicle control, these are mostly focused on energy management or cruise control, and their application in precise brake pressure adjustment remains immature. In particular, how to deeply integrate future road information with traditional braking control logic to achieve a brake pressure adjustment scheme capable of proactively identifying extreme conditions and actively presetting and smoothly switching pressure remains a pressing technical challenge in this field. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a predictive braking pressure regulation method and system to fundamentally overcome the response delay defects of traditional braking systems and improve the braking safety, stability, and ride comfort of vehicles under various complex road conditions.

[0005] In a first aspect, the present invention provides a predictive braking pressure regulation method, the method comprising: Obtain road information for the predetermined length of road ahead of the vehicle, including gradient sequence. and curvature sequence Where N is the number of road segments; and These represent the slope and curvature of the next road segment following the vehicle's current position, respectively; simultaneously, the vehicle's current speed is obtained. ; Obtain the basic target deceleration And based on the slope sequence The target deceleration is obtained by correcting the basic target deceleration; Obtain the base target slip ratio When the curvature sequence When the curvature is greater than the curvature threshold, based on the curvature sequence and current vehicle speed The target slip ratio is obtained by correcting the basic target slip ratio. When the road information ahead indicates that the pre-triggering conditions are met, pre-inflation is performed at a preset boost rate P0. When the vehicle enters a road segment that meets the pre-triggering conditions, the braking pressure is adjusted based on the target deceleration and / or the target slip ratio.

[0006] By acquiring the slope and curvature sequence of the road ahead through high-precision maps, the target deceleration and target slip ratio are corrected in advance. At the same time, a pre-boost mechanism is triggered for extreme working conditions, which solves the problem of response lag in traditional EBS braking systems when road conditions change abruptly. It avoids safety hazards such as excessive deceleration on uphill slopes and insufficient braking force on downhill slopes, significantly improving the predictability and timeliness of the braking system, and taking into account both braking safety and control efficiency.

[0007] As a further limitation of the technical solution of the present invention, the step of correcting the basic target deceleration includes: when When it is determined that the vehicle is about to go uphill, the target deceleration is reduced. :

[0008] when When it is determined that the vehicle is about to go downhill, the target deceleration is increased. :

[0009] when When it is determined that the vehicle is about to enter a steep downhill slope, the target deceleration is further increased:

[0010] In the formula, the slope threshold , For braking deceleration limits, , , All are correction factors. Deceleration of the basic target The basic target slip ratio.

[0011] Based on different deceleration correction logics for different slope ranges, and through graded thresholds and corresponding correction coefficients, the gravity influence characteristics of uphill, downhill and steep downhill are accurately matched. This ensures the braking force compensation effect when going downhill, and avoids the risk of wheel lock-up when braking on steep downhill by limiting the braking deceleration. This further optimizes the rationality of the target deceleration and improves the accuracy and stability of braking control under different slope conditions.

[0012] As a further limitation of the technical solution of the present invention, the step of correcting the basic target slip ratio includes: According to the curvature sequence and current vehicle speed Calculate lateral acceleration When the lateral acceleration is greater than the lateral acceleration threshold At that time, the basic target slip ratio is corrected to obtain the target slip ratio. ;

[0013]

[0014] In the formula, The attenuation coefficient is... This represents the upper limit of lateral acceleration.

[0015] By combining the curvature of the road ahead and the current vehicle speed to calculate lateral acceleration, the target slip ratio is corrected only when the lateral acceleration exceeds a threshold. This avoids the risk of vehicle skidding due to excessive slip ratio during braking on curves with high curvature, through the attenuation coefficient. and upper limit of lateral acceleration The constraints ensure that the slip ratio correction range conforms to the vehicle's dynamic characteristics, thereby improving driving stability during cornering braking.

[0016] As a further limitation of the technical solution of the present invention, the pre-triggering condition is: satisfying and , and , , At least one of the conditions; In the formula, The preset extreme working condition slope threshold, This is the preset curvature threshold for extreme operating conditions.

[0017] The pre-triggering conditions for extreme working conditions are clearly defined. Dangerous scenarios are identified by the gradient (including the absolute value of negative gradient) and curvature of the two road sections ahead. The pre-boost mechanism is activated in advance to solve the problem of insufficient initial braking force under extreme working conditions. Sufficient braking pressure reserves are reserved before the vehicle enters dangerous road sections, further shortening the braking response time and reducing the braking safety risks in extreme scenarios such as steep downhill slopes and sharp curves.

[0018] As a further limitation of the technical solution of the present invention, the basic target deceleration Obtained through the following methods: The brake pedal opening and driver driving style are obtained, and the driver driving style is quantified into multiple types including mild, normal and aggressive. Based on the pedal opening and driving style, the corresponding basic deceleration table is consulted, and the basic target deceleration is calculated by interpolation. .

[0019] By combining the driver's driving style (mild, normal, aggressive) with the brake pedal opening, and obtaining the basic target deceleration through table lookup interpolation, the braking control is adapted to the operating habits of different drivers, avoiding the problem of poor driving experience caused by a uniform deceleration standard. This improves driving comfort while ensuring braking safety, and enhances the applicability and humanization of the braking system.

[0020] As a further limitation of the technical solution of the present invention, the basic target slip ratio This is obtained by querying a preset mapping table related to the current vehicle status and road conditions.

[0021] The basic target slip ratio is obtained based on a pre-set mapping table of current vehicle and road conditions, so that... The initial value is more in line with the real-time driving scenario, avoiding the problem of poor road adaptability caused by fixed slip ratio, providing a precise benchmark for subsequent slip ratio correction, and further improving the adaptability and control accuracy of the braking system under different driving conditions.

[0022] As a further limitation of the technical solution of the present invention, the method further includes: The actual slope at the current location is obtained through sensors, and compared with the slope at the current location obtained from the map. When comparing the two values, if the difference is greater than the preset range, the slope is predicted based on the sensor slope and its historical data, and the predicted slope is used as the basis for adjusting the braking pressure.

[0023] By comparing and verifying the actual slope with the map slope using sensors, and through a historical data prediction and compensation mechanism, the problem of slope information deviation that may exist in high-precision maps is solved. This ensures that the slope data on which the braking pressure adjustment is based is true and reliable, avoids braking control failure caused by map errors, adds dual data verification protection to the braking system, and improves the robustness and safety of the overall solution.

[0024] As a further limitation of the technical solution of the present invention, the step of adjusting the braking pressure based on the target deceleration and / or target slip ratio specifically includes: Real-time acquisition of the vehicle's actual deceleration and / or actual slip ratio; Calculate the first error between the actual deceleration and the target deceleration and / or the second error between the actual slip ratio and the target slip ratio; Based on the first error and / or the second error, a braking pressure control command is determined and output through a closed-loop control algorithm.

[0025] The closed-loop control algorithm dynamically adjusts the braking pressure based on the error between the actual and target parameters, replacing the traditional open-loop control method. It can correct deviations in the braking process in real time (such as insufficient actual deceleration or excessive slip ratio), improve the dynamic response speed and control accuracy of braking pressure adjustment, and avoid the braking effect deviating from the expected due to actuator error or road condition fluctuations, thus further ensuring the stability and reliability of braking control.

[0026] Secondly, the present invention also provides a predictive braking pressure regulation system, the system comprising: The road information acquisition module is configured to acquire road information for a predetermined length of road ahead of the vehicle, including slope sequence. and curvature sequence Where N is the number of road segments; and These represent the slope and curvature of the next section of road following the vehicle's current position, respectively. The vehicle status acquisition module is configured to acquire the vehicle's current speed. ; The target deceleration determination module is configured to obtain the basic target deceleration. And based on the slope sequence The target deceleration is obtained by correcting the basic target deceleration; The target slip ratio determination module is configured to obtain the basic target slip ratio. When the curvature sequence When the curvature is greater than the curvature threshold, based on the curvature sequence and current vehicle speed The target slip ratio is obtained by correcting the basic target slip ratio. The pre-boost control module is configured to pre-boost at a preset boost rate P0 when the road information ahead indicates that the pre-triggering conditions are met. The brake pressure adjustment module is configured to adjust the brake pressure based on the target deceleration and / or target slip ratio when the vehicle enters a road segment that meets the pre-trigger conditions.

[0027] By clearly defining the division of labor among the functional units through modular design, the road information and vehicle status acquisition module provides accurate input for predictive control, the target parameter determination module ensures the rationality of the control benchmark, the pre-boost and braking pressure adjustment module realizes precise control in stages, and the collaborative work of each module ensures the efficient implementation of predictive braking logic, thereby improving the overall maintainability and scalability of the system.

[0028] As a further limitation of the technical solution of the present invention, when the target deceleration determination module is configured to correct the basic target deceleration, it specifically performs the following operations: when When it is determined that the vehicle is about to go uphill, the target deceleration is reduced. :

[0029] when When it is determined that the vehicle is about to go downhill, the target deceleration is increased. :

[0030] when When it is determined that the vehicle is about to enter a steep downhill slope, the target deceleration is further increased:

[0031] In the formula, the slope threshold , For braking deceleration limits, , , All are correction factors. Deceleration of the basic target The basic target slip ratio.

[0032] As a further limitation of the technical solution of the present invention, when the target slip ratio determination module is configured to correct the basic target slip ratio, it specifically performs the following operations: According to the curvature sequence and current vehicle speed Calculate lateral acceleration When the lateral acceleration is greater than the lateral acceleration threshold At that time, the basic target slip ratio is corrected to obtain the target slip ratio. ;

[0033]

[0034] In the formula, The attenuation coefficient is... This represents the upper limit of lateral acceleration.

[0035] As a further limitation of the technical solution of the present invention, the pre-triggering condition is: satisfying and , and , , At least one of the conditions; In the formula, The preset extreme working condition slope threshold, This is the preset curvature threshold for extreme operating conditions.

[0036] As a further limitation of the technical solution of the present invention, the target deceleration determination module is configured to obtain the basic target deceleration in the following manner. : The brake pedal opening and driver driving style are obtained, and the driver driving style is quantified into multiple types including mild, normal and aggressive. Based on the pedal opening and driving style, the corresponding basic deceleration table is consulted, and the basic target deceleration is calculated by interpolation. .

[0037] As a further limitation of the technical solution of the present invention, the target slip ratio determination module is configured to obtain the basic target slip ratio by querying a preset mapping table related to the current vehicle state and road surface state. .

[0038] As a further limitation of the technical solution of the present invention, the system also includes a security verification module, configured as follows: The actual slope at the current location is obtained through sensors, and compared with the slope at the current location obtained from the map. Compare; When the difference between the two values ​​is greater than the preset range, the slope prediction is based on the sensor slope and its historical data. The predicted slope is used as the basis for adjusting the braking pressure.

[0039] As a further limitation of the technical solution of the present invention, the brake pressure regulating module is configured to perform the following operations: Real-time acquisition of the vehicle's actual deceleration and / or actual slip ratio; Calculate the first error between the actual deceleration and the target deceleration and / or the second error between the actual slip ratio and the target slip ratio; Based on the first error and / or the second error, a braking pressure control command is determined and output through a closed-loop control algorithm.

[0040] As can be seen from the above technical solutions, this application has the following advantages: by acquiring the slope and curvature of the future road, the target deceleration or target slip ratio of the braking pressure adjustment can be corrected accordingly; simultaneously, when extreme working conditions are about to occur, the problem of insufficient initial braking force is optimized by pre-pressurization; furthermore, the accuracy of future slope information is ensured by performing safety verification between slope sensor data and map data. This invention, by introducing future road information, enables the braking system to have a certain degree of predictability, alleviating the delay problem of braking pressure adjustment to a certain extent and improving braking safety and efficiency. Attached Figure Description

[0041] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a flowchart illustrating the method provided in an embodiment of the present invention.

[0043] Figure 2 A block diagram of a system provided in an embodiment of the present invention. Detailed Implementation

[0044] To make the purpose, features, and advantages of this application more apparent and understandable, specific embodiments and accompanying drawings will be used to clearly and completely describe the technical solution protected by this application. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0045] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this application and in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0046] like Figure 1 As shown, an embodiment of the present invention provides a predictive braking pressure regulation method, the method comprising: S1. Obtain road information for the predetermined length of road ahead of the vehicle, including the gradient sequence. and curvature sequence Where N is the number of road segments; and These represent the slope and curvature of the next road segment following the vehicle's current position, respectively; simultaneously, the vehicle's current speed is obtained. ; S2, Obtain the basic target deceleration And based on the slope sequence The target deceleration is obtained by correcting the basic target deceleration; S3, Obtain the base target slip ratio When the curvature sequence When the curvature is greater than the curvature threshold, based on the curvature sequence and current vehicle speed The target slip ratio is obtained by correcting the basic target slip ratio. S4. When the road information ahead indicates that the pre-triggering conditions are met, pre-inflation is performed at a preset boost rate P0. When the vehicle enters a road segment that meets the pre-triggering conditions, the braking pressure is adjusted based on the target deceleration and / or the target slip ratio.

[0047] It should be noted that when the pre-trigger condition is met, the electronic control unit (ECU) generates a signal starting from the current braking pressure and at a fixed slope. Target pressure command that increases linearly over time The system controls the brake actuators (such as hydraulic pumps and solenoid valves) to follow the command, causing the braking system pressure to rise at a constant rate until the vehicle enters a road section that meets the pre-triggered conditions or the pressure reaches a preset upper limit. Until then. The specific steps are as follows: When the system determines that the pre-triggering condition is met (for example, ... When this occurs, the electronic control unit (ECU) immediately initiates the pre-boost program.

[0048] The ECU records the current initial value of the brake pressure. (Usually close to 0 Bar).

[0049] The ECU operates at a fixed rate. (Unit: Bar / second or MPa / second) is used as the slope to generate a target pressure command that increases linearly with time. .

[0050] The calculation formula is as follows:

[0051] in It is the time elapsed since the pre-boost started.

[0052] The ECU will execute the above ramp command. Sending signals to the actuators of the braking system (typically hydraulic pumps and pressure regulating solenoid valves).

[0053] Instead of receiving complex closed-loop feedback commands, the actuator focuses on supplying oil to the brake wheel cylinder at the most constant flow rate possible, thereby physically achieving a uniform pressure rise.

[0054] The system monitors the actual pressure in real time using pressure sensors to ensure close tracking. The ramp curve prevents execution deviations.

[0055] This pre-pressurization process continues until one of the following conditions is met: (a) Vehicle enters the target road segment: i.e., the slope of the vehicle's current position. or curvature It meets the extreme operating conditions ( or At this point, the system immediately exits the pre-boost mode and switches to a closed-loop control mode based on the target deceleration / slip ratio.

[0056] (b) Reaching the pressure limit: To prevent excessive pre-boosting from causing wheel lock-up, a pre-boost pressure limit is set. (e.g., 30 Bar). Once Once this limit is reached, the pressure will remain at this limit value even if condition (a) is not met, until condition (a) is triggered.

[0057] In this embodiment of the invention, the step of correcting the basic target deceleration includes: when When it is determined that the vehicle is about to go uphill, the target deceleration is reduced. :

[0058] when When it is determined that the vehicle is about to go downhill, the target deceleration is increased. :

[0059] when When it is determined that the vehicle is about to enter a steep downhill slope, the target deceleration is further increased:

[0060] In the formula, the slope threshold , For braking deceleration limits, , , All are correction factors. Deceleration of the basic target The basic target slip ratio.

[0061] It is the sensitivity threshold for judging when an uphill section is about to begin; It is the threshold for determining whether to enter a gentle downhill slope; It is the threshold for determining whether to enter a steep downhill slope. The angle is set to a small positive angle (0.5° to 2° in this embodiment of the invention) to indicate that adjustment begins when a slight uphill slope is detected ahead.

[0062] It can be set to a negative angle, for example. Between -0.5° and -2° Between -3° and -6°. The determination of these values ​​relies on extensive road testing to find the points of gradient change that affect vehicle dynamics and are perceptible to the driver.

[0063] The correction factor determines the aggressiveness of the compensation for the gravity component when dealing with slopes. The larger the value, the greater the compensation and the more aggressive the braking system response.

[0064] This is the uphill compensation factor, typically set between 0.1 and 0.5. Gravity provides auxiliary braking when going uphill, so this factor is used to reduce braking force and prevent excessive deceleration.

[0065] To mitigate the downhill slope, the compensation coefficient is typically set between 0.2 and 0.8. This is to compensate for the acceleration caused by gravity when descending a slope.

[0066] The compensation coefficient for steep downhill slopes is typically set between 0.5 and 1.2. For steep downhill slopes, a greater level of compensation is required.

[0067] The correction factor is ultimately determined to ensure that the actual deceleration of the vehicle meets the driver's expectations and comfort. This requires iterative optimization through real-vehicle testing and collecting driver feedback.

[0068] Braking deceleration limit This is a braking deceleration limit set to ensure safety and prevent wheel lock-up, skidding, or passenger discomfort caused by excessive braking. The braking deceleration limit is primarily limited by the road surface adhesion coefficient and vehicle axle load distribution. It is usually set as a large negative value, such as -8 m / s² to -10 m / s². In extreme cases, it can be set with reference to the maximum deceleration achievable by the vehicle's anti-lock braking system under full braking.

[0069] In this embodiment of the invention, the step of correcting the basic target slip ratio includes: According to the curvature sequence and current vehicle speed Calculate lateral acceleration When the lateral acceleration is greater than the lateral acceleration threshold At that time, the basic target slip ratio is corrected to obtain the target slip ratio. ;

[0070]

[0071] In the formula, The attenuation coefficient is... This represents the upper limit of lateral acceleration.

[0072] Lateral acceleration threshold attenuation coefficient lateral acceleration limit All parameters are calibrable. Their specific values ​​need to be determined based on the target vehicle's model, chassis stability, tire characteristics, and target driving style, using conventional real-vehicle testing and calibration methods in this field. The principles for setting each parameter are as follows: Lateral acceleration threshold This represents the critical point at which the vehicle begins to exhibit noticeable body roll or the lateral force from the tires begins to have a significant impact on lateral acceleration. Slip rate decay is only triggered when the calculated lateral acceleration exceeds this threshold. It is typically set between 0.15g and 0.25g (i.e., 1.47 m / s² to 2.45 m / s²). (Drop coefficient) This coefficient determines the extent to which the target slip ratio decreases with increasing lateral acceleration in a corner. A larger coefficient allows for a lower allowable slip ratio (i.e., braking force) in a corner, ensuring sufficient lateral grip from the tires to maintain vehicle stability. This is a critical safety factor, typically determined through extensive testing, and ranges from 1.2 to 2.0. Calibration must ensure that braking will not lead to loss of control under extreme conditions such as wet or slippery surfaces or high-speed cornering.

[0073] Upper limit of lateral acceleration This represents the near-limit lateral acceleration that a vehicle can withstand under current road surface and conditions. In the formula, it serves as a normalization benchmark used to calculate the attenuation ratio of the slip ratio. This value is directly related to the vehicle model and tire performance, and is typically set between 0.3g and 0.5g (i.e., 2.94 m / s² to 4.90 m / s²). Higher values ​​can be used for high-performance vehicles or dry asphalt roads; lower values ​​can be used for ordinary passenger cars or to ensure a safety margin.

[0074] It should be further noted that the pre-triggering condition is: satisfying and , and , , At least one of the conditions; In the formula, The preset extreme working condition slope threshold, This is the preset curvature threshold for extreme operating conditions.

[0075] This is the extreme slope threshold, a critical slope value used to determine whether the slope has reached an extreme level or requires pre-pressurization. It refers to the absolute value of the future road segment's slope. or If the slope exceeds this threshold and is negative (i.e., downhill), the system determines it to be an extreme slope condition that requires pre-pressurization.

[0076] This is the extreme curvature threshold, a critical curvature value used to determine whether the road curvature has reached an extreme level or requires pre-boosting. When the absolute value of the future road segment's curvature... or When the value exceeds this threshold, the system determines that it is an extreme curvature condition that requires pre-boosting.

[0077] The extreme working condition slope threshold and curvature threshold under extreme operating conditions All of these are calibrable parameters. Their specific values ​​need to be determined based on the target vehicle's braking performance, chassis stability, tire characteristics, and safety regulations, using conventional real-vehicle testing and calibration methods in this field.

[0078] The braking force setting should be based on the additional braking force required to ensure the vehicle can descend the slope at a safe speed. Refer to the definition of a steep slope in road traffic design specifications. For example, in highway engineering technical standards, the maximum longitudinal slope for Class I highways is 4%-6%, which translates to an angle of approximately 2.3° to 3.4°. Simulations based on vehicle dynamics models can be used to find a slope value that requires pre-boost to maintain deceleration within a specified range at a given initial velocity.

[0079] Based on the above, A reasonable exemplary range could be set between -3° and -5° (approximately -0.052 rad to -0.087 rad). That is, when a continuous downhill slope exceeding 3° to 5° is detected ahead, the system will consider it an extreme slope condition that requires advance preparation.

[0080] The settings should be based on the vehicle's lateral acceleration approaching its comfort or stability limits when cornering at a specific speed. Its reciprocal 1 / This refers to the turning radius. You can refer to the typical design radius of highway ramps or sharp bends in mountainous areas. For example, the minimum design radius of a highway ramp is usually around 100 to 200 meters. Therefore, It can be set to a curvature value corresponding to a turning radius of 100 to 200 meters.

[0081] The curvature k = 1 / R (where R is the radius).

[0082] so An exemplary range is approximately 0.005 m. - ¹ to 0.01 m - ¹ (i.e., R=200 meters to R=100 meters). In other words, when a curve with a turning radius of less than 100 to 200 meters is detected ahead, the system will activate pre-boost.

[0083] In this embodiment of the invention, the basic target deceleration Obtained through the following methods: The brake pedal opening and driver driving style are obtained, and the driver driving style is quantified into multiple types including mild, normal and aggressive. Based on the pedal opening and driving style, the corresponding basic deceleration table is consulted, and the basic target deceleration is calculated by interpolation. .

[0084] It should be noted that the basic deceleration table is constructed as follows: Real-world testing was conducted using the target vehicle model on a flat, dry, standard road surface.

[0085] For three preset driving styles—mild, normal, and aggressive—representative drivers were recruited to perform braking operations.

[0086] Instruct the driver to brake at different speeds with varying brake pedal openings (from 0% to 100%, increasing at fixed intervals such as 10%), and inform them that the goal is to achieve a comfortable and effective deceleration in that style.

[0087] The system synchronously records the brake pedal opening, actual vehicle deceleration, and driver style label for each braking action via the vehicle's CAN bus.

[0088] The collected data is cleaned and filtered to remove data points of abnormal braking (such as emergency avoidance).

[0089] Normalize the data at different vehicle speeds, or establish a multidimensional lookup table model with vehicle speed as the variable. The main focus is on establishing a two-dimensional mapping relationship between pedal opening and deceleration.

[0090] For all effective deceleration data under the same pedal opening and driving style, perform statistical averaging (such as taking the arithmetic mean) to form a standard deceleration value corresponding to each pedal opening under that style.

[0091] The processed data was used to generate three pedal opening-target deceleration curves for the three driving styles.

[0092] Discretize these three curves to generate three independent basic deceleration tables.

[0093] This initially generated table is written into the vehicle controller (EBS) and calibrated and verified on a real vehicle. Based on the driver's subjective feelings and objective performance indicators (such as braking smoothness), the values ​​in the table are fine-tuned until the optimal driving experience is achieved.

[0094] The vehicle's human-machine interface (such as the central control screen or instrument panel) provides a braking style selection menu, including options such as mild, normal, and aggressive. After the driver actively selects a style, the system sends the selection signal to the electronic braking system (EBS) and stores it in non-volatile memory. The system then calls up the base deceleration gauge corresponding to the selected style each time braking occurs.

[0095] Table 1 provides an example of a specific deceleration representation that can be obtained using the method described above. This example is based on the following assumptions: Pedal opening sampling points: [0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%]; Unit: deceleration is measured in m / s² (negative values ​​indicate deceleration).

[0096] Table 1: Examples of Basic Deceleration

[0097] Once the system obtains the pedal opening (e.g., 25%) and driving style (e.g., "Normal"), it will find the decelerations (-1.0 and -1.8) corresponding to the opening of 20% and 30% in the "Normal Style" column.

[0098] Then, calculations were performed using linear interpolation:

[0099] Calculated 1.4 m / s 2 The current basic target is deceleration. .

[0100] The basic target slip ratio This is obtained by querying a preset mapping table related to the current vehicle status and road conditions.

[0101] This mapping table is a multi-dimensional data structure that reflects the optimal slip ratio that a wheel needs to maintain to achieve maximum braking force on road surfaces with different coefficients of adhesion. The generation of this mapping table is based on classic... - The curve relationship is established through the following steps: Longitudinal adhesion coefficient between tire and road surface With slip ratio The changes form a typical curve relationship. This curve usually has a peak point, and the slip ratio corresponding to this peak point is the optimal slip ratio. At this point, the tire can provide the maximum braking force. The area after the peak point is an unstable region, where the slip ratio increases and the coefficient of adhesion decreases, making it easy for the wheels to lock up.

[0102] The core of this mapping table is to find this under different conditions. and set it as .

[0103] The dimensions and key parameters for constructing the mapping table include: Key input variables (lookup dimensions): Predicted road surface adhesion coefficient This is the most important dimension. The optimal slip ratio varies for different road surfaces (approximately 0.05-0.1 for ice, 0.1-0.2 for snow, and 0.15-0.25 for dry asphalt).

[0104] Vehicle load: Vehicle load affects the tire's contact patch characteristics, thus slightly affecting the optimal slip ratio.

[0105] Vehicle speed (V): In some sophisticated models, vehicle speed is also used as a correction dimension.

[0106] Output variable: Base target slip ratio .

[0107] The specific generation process through offline calibration includes: Step 1: Data Collection Tests were conducted using the target vehicle model on various typical road surfaces (such as dry asphalt, wet asphalt, compacted snow, ice, etc.).

[0108] Allow the vehicle to brake in progressively increasing steps at different speeds and loads, or use ABS hardware to rapidly cycle and release braking pressure.

[0109] The wheel slip ratio is collected synchronously at every moment using high-precision sensors. and the calculated longitudinal adhesion coefficient .

[0110] Step 2: Curve Fitting and Feature Extraction A large number of data were collected under each fixed working condition (e.g., "dry asphalt pavement, half load, 80 km / h") , Data points are used for curve fitting to obtain a clear curve. - curve.

[0111] The algorithm identifies the peak point of each curve and records the optimal slip ratio corresponding to that peak point. and the peak adhesion coefficient at this time .

[0112] Step 3: Table creation and interpolation The results under all the above test conditions ( ≈ Load, V-> = Organize them into a multidimensional database.

[0113] Since the test conditions are discrete, an interpolation algorithm (such as linear interpolation) is used to fill the table, generating a continuous and smooth preset mapping table that covers all possible conditions, and then burning it into the EBS controller.

[0114] Table 2 is a highly simplified two-dimensional representation for estimating the road surface adhesion coefficient. The primary dimension is ignoring the subtle effects of load and vehicle speed. Load: half load, vehicle speed: 50-80 km / h, used to illustrate the implementation principle of this application.

[0115] Table 2: Basic Target Slip Ratio Mapping representation example

[0116] During normal driving or initial braking, the EBS or related chassis domain controllers (such as ESC) estimate the current road adhesion coefficient in real time by analyzing minute fluctuations in wheel speed or changes in tire stiffness. This is a mature, existing technology for identification.

[0117] The estimated Using (e.g., 0.4) as input, query Table 2. Determine the current value through interpolation. It is approximately 0.19 (i.e., 19%). = 0.19 will serve as the baseline target slip ratio for all subsequent slip ratio controls (including curvature-based corrections).

[0118] In some embodiments, the method further includes: The actual slope at the current location is obtained through sensors, and compared with the slope at the current location obtained from the map. When comparing the two values, if the difference is greater than the preset range, the slope is predicted based on the sensor slope and its historical data, and the predicted slope is used as the basis for adjusting the braking pressure.

[0119] Slope prediction is achieved using existing prediction methods based on sensor slope as a benchmark and its historical data.

[0120] In some embodiments, the step of adjusting the braking pressure based on the target deceleration and / or target slip ratio specifically includes: Real-time acquisition of the vehicle's actual deceleration and / or actual slip ratio; Calculate the first error between the actual deceleration and the target deceleration, and / or the second error between the actual slip ratio and the target slip ratio; Based on the first error and / or the second error, a braking pressure control command is determined and output through a closed-loop control algorithm.

[0121] The electronic control unit (ECU) sends the brake pressure control command. The signal is converted into a corresponding electric drive signal to drive the actuators of the braking system (especially the high-pressure solenoid valve) to operate. By controlling the pressurization, pressure holding or depressurization state of the solenoid valve, the fluid pressure in the brake wheel cylinder is precisely adjusted, thereby achieving dynamic control of vehicle braking.

[0122] The step of adjusting the braking pressure based on the target deceleration and / or target slip ratio when the vehicle enters a road segment that meets the pre-triggering conditions specifically includes the following process: Continuously monitor the slope of the vehicle's current location. and curvature .

[0123] When satisfied and <0 or If any of the conditions in the above conditions are met, it is determined that the vehicle has entered the previously predicted extreme road condition section. At this time, the control logic switch is immediately triggered.

[0124] The control unit issues a command to stop the pre-boost process, which is proceeding at a fixed rate P0. The braking pressure is then maintained at the value achieved during the current pre-boost, serving as the initial pressure for subsequent precise adjustments.

[0125] The system switches to target deceleration-based and / or target slip ratio The closed-loop control mode.

[0126] The vehicle's actual deceleration is obtained in real time through the onboard sensor network. and / or the actual slip ratio of the wheel .

[0127] Calculate the error between the target value and the actual value.

[0128] Deceleration error: = -

[0129] Slip ratio error: = -

[0130] Based on the aforementioned error, a predetermined control algorithm calculates the braking pressure adjustment required to eliminate the error and outputs the final braking pressure command. For example, when the actual deceleration is less than the target deceleration, the controller will command to increase the braking pressure; conversely, it will decrease it.

[0131] In this embodiment of the invention, the control algorithm adopts the PID control algorithm, and the specific execution steps are as follows: The controller receives the calculated error signal .

[0132] When performing deceleration control .

[0133] When performing slip ratio control .

[0134] PID controller for error signals By performing proportional (P), integral (I), and derivative (D) calculations and weighted summation, the adjustment amount of braking pressure (or control output) is calculated. .

[0135] The standard calculation formula is as follows:

[0136] in: The output of the controller is the required adjustment amount of braking pressure (unit: Bar or Pa).

[0137] This is a proportional gain, producing an output that is proportional to the current error, used for rapid error response. Too small a value will result in a slow response, while too large a value will cause oscillations.

[0138] The integral gain is calculated by integrating the error (i.e., the cumulative value of the error over time) to eliminate the steady-state error (static error) of the system. For example, when the actual deceleration remains slightly below the target value, the integral term will continue to increase the output until the error is zero.

[0139] The differential gain is calculated on the rate of change of the error (i.e., whether the error is expanding or shrinking) to predict the future trend of the error, producing a damping effect that suppresses overshoot and oscillation, thereby improving the stability of the system.

[0140] Calculated output It will pass through an output limiter to restrict it to the range allowed by the system. For example, [-150Bar, +150Bar], to prevent output instructions from exceeding the physical limits of the actuator.

[0141] At the same time, the algorithm integrates anti-integral saturation logic. When the output is continuously in a limited state (for example, when the system is building up pressure at full capacity), the accumulation of the integral term will be stopped to prevent the integral term from becoming too large, which would cause the system to respond slowly when exiting the saturation region (i.e., the "integral saturation" phenomenon).

[0142] After amplitude limiting As the final brake pressure adjustment command, it is sent to the actuators of the braking system (such as the solenoid valves in EBS). Based on this command, the actuators precisely increase, maintain, or decrease the pressure in the brake lines, thereby dynamically adjusting the braking force. or Approaching or .

[0143] The electronic control unit (ECU) receives brake pressure control commands calculated by a closed-loop control algorithm. This instruction is a pressure adjustment (e.g., "increase by 50 bar" or "decrease by 30 bar").

[0144] The ECU determines vehicle stability requirements (such as whether to trigger ESC / ABS) and The value determines which wheel brake actuators (e.g., single, coaxial, or all four wheels) are assigned the command.

[0145] The ECU will send pressure commands in digital form. The signal is converted into a high-current control signal that can drive a brake actuator (such as a high-pressure solenoid valve) through a digital-to-analog converter (DAC) and a power amplifier circuit. The characteristics of this control signal (such as current magnitude, duty cycle (PWM), or switching frequency) correspond precisely to the braking pressure that needs to be established or released.

[0146] The brake actuator (taking a solenoid valve as an example) performs one of the following three basic actions based on the received electrical signal to adjust the wheel cylinder braking pressure: Boost: When When the pressure is >0 (i.e., pressure needs to be increased), the ECU drives the boost valve to open, and the isolation valve remains in the corresponding state, allowing brake fluid from the high-pressure accumulator or master pump to flow into the wheel cylinder, increasing the pressure.

[0147] Holding pressure: When When the pressure is approximately 0 (i.e., the target pressure has been reached), the ECU drives the boost valve and the depressurization valve to close simultaneously, sealing the brake fluid inside the wheel cylinder and maintaining a constant current pressure.

[0148] Stress reduction: When When the pressure is less than 0 (i.e., pressure needs to be reduced), the ECU drives the pressure relief valve to open and the pressure boosting valve to close, allowing some brake fluid to flow from the wheel cylinder back to the reservoir, thus reducing the pressure.

[0149] While regulating the pressure, the system again collects the actual braking pressure and actual deceleration in real time through the wheel cylinder pressure sensor and the vehicle status sensor. and / or actual slip ratio The actual value is fed back to the input of the control algorithm, and the error is recalculated. Repeat the above steps to form a continuous, dynamic closed-loop adjustment until the error between the actual value and the target value is eliminated or stabilized within the allowable range.

[0150] like Figure 2 As shown, embodiments of the present invention also provide a predictive braking pressure regulation system, the system comprising: The road information acquisition module is configured to acquire road information for a predetermined length of road ahead of the vehicle, including slope sequence. and curvature sequence Where N is the number of road segments; and These represent the slope and curvature of the next section of road following the vehicle's current position, respectively. The vehicle status acquisition module is configured to acquire the vehicle's current speed. ; The target deceleration determination module is configured to obtain the basic target deceleration. And based on the slope sequence The target deceleration is obtained by correcting the basic target deceleration; The target slip ratio determination module is configured to obtain the basic target slip ratio. When the curvature sequence When the curvature is greater than the curvature threshold, based on the curvature sequence and current vehicle speed The target slip ratio is obtained by correcting the basic target slip ratio. The pre-boost control module is configured to pre-boost at a preset boost rate P0 when the road information ahead indicates that the pre-triggering conditions are met. The brake pressure adjustment module is configured to adjust the brake pressure based on the target deceleration and / or target slip ratio when the vehicle enters a road segment that meets the pre-trigger conditions.

[0151] By clearly defining the division of labor among the functional units through modular design, the road information and vehicle status acquisition module provides accurate input for predictive control, the target parameter determination module ensures the rationality of the control benchmark, the pre-boost and braking pressure adjustment module realizes precise control in stages, and the collaborative work of each module ensures the efficient implementation of predictive braking logic, thereby improving the overall maintainability and scalability of the system.

[0152] In some embodiments, when the target deceleration determination module is configured to correct the basic target deceleration, it specifically performs the following operations: when When it is determined that the vehicle is about to go uphill, the target deceleration is reduced. :

[0153] when When it is determined that the vehicle is about to go downhill, the target deceleration is increased. :

[0154] when When it is determined that the vehicle is about to enter a steep downhill slope, the target deceleration is further increased:

[0155] In the formula, the slope threshold , For braking deceleration limits, , , All are correction factors. Deceleration of the basic target The basic target slip ratio.

[0156] In some embodiments, when the target slip ratio determination module is configured to correct the base target slip ratio, it specifically performs the following operations: According to the curvature sequence and current vehicle speed Calculate lateral acceleration When the lateral acceleration is greater than the lateral acceleration threshold At that time, the basic target slip ratio is corrected to obtain the target slip ratio. ;

[0157]

[0158] In the formula, The attenuation coefficient is... This represents the upper limit of lateral acceleration.

[0159] The pre-trigger condition is: satisfying and , and , , At least one of the conditions; In the formula, The preset extreme working condition slope threshold, This is the preset curvature threshold for extreme operating conditions.

[0160] In some embodiments, the target deceleration determination module is configured to obtain the basic target deceleration by means of the following method. : The brake pedal opening and driver driving style are obtained, and the driver driving style is quantified into multiple types including mild, normal and aggressive. Based on the pedal opening and driving style, the corresponding basic deceleration table is consulted, and the basic target deceleration is calculated by interpolation. .

[0161] The target slip ratio determination module is configured to obtain the basic target slip ratio by querying a preset mapping table related to the current vehicle state and road surface state. .

[0162] In some embodiments, the system further includes a security verification module, configured as follows: The actual slope at the current location is obtained through sensors, and compared with the slope at the current location obtained from the map. Compare; When the difference between the two values ​​is greater than the preset range, the slope prediction is based on the sensor slope and its historical data. The predicted slope is used as the basis for adjusting the braking pressure.

[0163] In some embodiments, the brake pressure regulating module is configured to perform the following operations: Real-time acquisition of the vehicle's actual deceleration and / or actual slip ratio; Calculate the first error between the actual deceleration and the target deceleration and / or the second error between the actual slip ratio and the target slip ratio; Based on the first error and / or the second error, a braking pressure control command is determined and output through a closed-loop control algorithm.

[0164] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A predictive brake pressure regulation method, characterized in that, The method comprises: Obtaining road information of a road of a predetermined length ahead of the vehicle, including a slope sequence and a curvature sequence , wherein N is the number of road segments; and respectively represent the slope and curvature of the next road segment following the current position of the vehicle; meanwhile, obtaining the current vehicle speed ; obtaining a base target deceleration and based on the sequence of slopes correcting the base target deceleration to obtain a target deceleration Acquiring a basic target slip ratio When the curvature sequence is greater than a curvature threshold value Based on the curvature sequence and the current vehicle speed and the current vehicle speed The basic target slip ratio is corrected to obtain a target slip ratio When it is judged according to the road information of the front road that the pre-trigger condition is met, pre-pressurization is performed at a preset pressurization rate P0, and when the vehicle enters a road section meeting the pre-trigger condition, adjustment of the brake pressure is switched to be based on the target deceleration and / or the target slip rate.

2. The predictive brake pressure regulation method according to claim 1, characterized in that The step of correcting the basic target deceleration comprises: When the vehicle is judged to be about to go uphill, the target deceleration is lowered : When the vehicle is judged to be about to descend a slope, the target deceleration is increased : When a vehicle is judged to be about to enter a steep downward slope, the target deceleration is continuously increased: wherein the slope threshold value , is a braking deceleration limit value, 、 、 are correction factors, is a base target deceleration, is a base target slip ratio.

3. The predictive brake pressure regulation method according to claim 2, characterized in that, The step of correcting the basic target slip rate comprises: According to the curvature sequence and the current vehicle speed Calculate the lateral acceleration When the lateral acceleration is greater than the lateral acceleration threshold The basic target slip ratio is corrected to obtain the target slip ratio ; wherein is the attenuation coefficient, is the lateral acceleration upper limit.

4. The predictive brake pressure regulation method according to claim 3, characterized in that The pre-trigger condition is that at least one of the following conditions is met and , and , , is met. In the formula, is a preset extreme working condition slope threshold value, is a preset extreme working condition curvature threshold value.

5. The predictive brake pressure regulation method according to claim 4, characterized in that the base target deceleration by The brake pedal opening and the driver's driving style are obtained, and the driver's driving style is quantified into multiple types including gentle, normal and aggressive; According to the pedal opening degree and driving style, a corresponding basic deceleration table is inquired, and a basic target deceleration is calculated through interpolation .

6. The predictive brake pressure regulation method according to claim 5, characterized in that the base target slip ratio obtained by querying a preset mapping table related to the current vehicle state and road surface state.

7. The predictive brake pressure regulation method according to claim 1, characterized in that, The method further comprises: The actual slope of the current position is acquired by the sensor, and the slope of the current position acquired from the map When the difference between the two is greater than a preset range, the slope of the sensor is taken as the reference, and the slope is predicted based on the historical data thereof, and the predicted slope is taken as the basis for adjusting the brake pressure.

8. The predictive brake pressure regulation method according to claim 6, characterized in that The step of switching to adjust the brake pressure based on the target deceleration and / or the target slip rate specifically comprises: The actual deceleration and / or the actual slip rate of the vehicle are obtained in real time; A first error between the actual deceleration and the target deceleration and / or a second error between the actual slip rate and the target slip rate is calculated; Based on the first error and / or the second error, a brake pressure control instruction is determined and output by a closed-loop control algorithm.

9. A predictive brake pressure regulating system characterized by, The system comprises: a road information acquisition module configured to acquire road information of a road of a predetermined length ahead of the vehicle, including a gradient sequence and a curvature sequence where N is the number of road segments; and represent the gradient and curvature of the next road segment following the current position of the vehicle, respectively. a vehicle state acquisition module configured to acquire a current vehicle speed of the vehicle ; a target deceleration determination module configured to obtain a basic target deceleration and correct the basic target deceleration based on the slope sequence to obtain the target deceleration a target slip ratio determination module configured to obtain a basic target slip ratio when the curvature sequence is greater than a curvature threshold, the basic target slip ratio is corrected based on the curvature sequence and a current vehicle speed and the current vehicle speed to obtain the target slip ratio ​ A pre-pressurization control module configured to perform pre-pressurization at a preset pressurization rate P0 when it is judged according to the road information of the front road that the pre-trigger condition is met; A brake pressure adjustment module configured to switch to adjust the brake pressure based on the target deceleration and / or the target slip rate when the vehicle enters a road section meeting the pre-trigger condition.

10. The predictive brake pressure regulating system of claim 9, wherein, When the target deceleration determination module is configured to correct the basic target deceleration, the following operations are specifically performed: When the vehicle is judged to be about to go uphill, the target deceleration is lowered When the vehicle is judged to be about to descend a slope, the target deceleration is increased : When a vehicle is judged to be about to enter a steep downward slope, the target deceleration is continuously increased: wherein the slope threshold value , is a braking deceleration limit value, 、 、 are correction factors, is a base target deceleration, is a base target slip ratio.

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