Control method and system for truck braking system

Abstract

The invention discloses a control method and system for a truck braking system, and the method comprises the steps: obtaining vehicle state data and environment data, carrying out the estimation of a road adhesion coefficient estimation value, a braking efficiency estimation value and a mass correction coefficient, generating an effective slope angle or an equivalent slope percentage based on the vehicle longitudinal inclination angle and road slope information, and carrying out the calculation of the effective slope angle or the equivalent slope percentage. The effective deceleration and brake sight distance results of the vehicle on the ramp road section are calculated, the actual available sight distance in front of the vehicle is obtained, the actual available sight distance and the brake sight distance are compared in real time, a comparison result is generated, and whether the comparison result and / or the effective deceleration meet at least one preset control condition or not is judged. And if so, triggering a corresponding early warning or control strategy. According to the method, comparable brake sight distance quantitative indexes can be obtained under the conditions of different gradients, different loads and different road surfaces, the weight and precision of the gradient on brake safety evaluation are improved, and the adaptability and safety of the system under the conditions of complex ramp road sections and severe road surfaces are remarkably improved.

Description

Technical Field

[0001] This application relates to the field of road traffic safety technology, and in particular to a control method and system for truck braking systems. Background Technology

[0002] In recent years, with the widespread use of heavy-duty trucks on highways, mountain roads, and urban expressways, truck braking safety has become increasingly prominent. Especially on long downhill slopes, complex inclines, and low-friction surfaces, truck braking distances increase significantly, leading to frequent brake failures, rear-end collisions, and loss of control accidents, posing a serious threat to road traffic safety. Existing technologies have equipped some vehicles with active safety devices such as anti-lock braking systems (ABS), electronic stability control systems (ESCs), adaptive cruise control systems, and automatic emergency braking systems. These systems typically rely on environmental perception devices such as forward-facing radar and cameras, combined with vehicle speed and distance to the vehicle ahead, to assess collision risk and implement deceleration or emergency braking when necessary.

[0003] However, existing technologies typically suffer from the following shortcomings: First, most systems neglect the quantitative impact of factors such as gradient and load, setting fixed or simple functional safety distances based solely on vehicle speed and distance to the vehicle ahead, without accurately calculating the achievable braking distance under current gradient, load, and road surface adhesion conditions. Especially in conditions such as long downhill slopes, the effective deceleration of heavy-duty trucks decreases significantly, but existing systems often still use flat road or nominal deceleration assumptions, easily leading to underestimated braking distances and insufficient safety margins. Second, current systems handle road surface adhesion coefficients and braking efficiency rather crudely, often using static or empirical parameters. In actual operation, road surface conditions (dry, wet, snowy, icy), braking system temperature, and wear conditions can cause significant changes in maximum available braking force and actual braking efficiency. Finally, for trucks, the total vehicle mass and axle load distribution vary greatly, from empty, half-loaded to fully loaded, and even overloaded, resulting in significant changes in braking distance and vehicle stability. Existing systems are mostly based on nominal curb weight or a small number of operating conditions, and do not incorporate the current measured total mass and axle load information into the braking distance model. As a result, they are often unable to dynamically adjust the safety sight distance requirements for different load conditions.

[0004] In summary, existing technologies have not yet provided a complete solution for trucks that can simultaneously consider road slope, road surface adhesion, vehicle total mass and braking system efficiency, and achieve intelligent calculation and linkage control of braking sight distance. There is an urgent need to propose an improved technical solution to enhance the active safety level of trucks under complex working conditions. Summary of the Invention

[0005] To address or partially address the problems existing in related technologies, this application provides a control method and system for truck braking systems, establishing a unified calculation framework for braking sight distance on sloping road sections for trucks, using braking sight distance as a core indicator to directly drive vehicle longitudinal control and early warning strategies.

[0006] The first aspect of this application provides a control method for a truck braking system, comprising the following steps: By acquiring vehicle status data and environmental data, we can estimate the road adhesion coefficient, braking efficiency, and mass correction coefficient. The vehicle status data includes the vehicle longitudinal tilt angle, and the environmental data includes road slope information and road surface condition. Based on the vehicle's longitudinal tilt angle and road slope information, an effective slope angle or equivalent slope percentage is generated. The effective deceleration and braking sight distance of the vehicle on the sloping road section are calculated. The braking sight distance results include braking distance, reaction distance, safety margin term and braking sight distance. The safety margin term is determined in combination with the environment and road conditions. The actual available line of sight in front of the vehicle is obtained, and the actual available line of sight is compared with the braking line of sight in real time to generate a comparison result. The actual available line of sight is collected based on the vehicle-mounted sensing device. Determine whether the comparison result and / or effective deceleration meet at least one preset control condition; if so, trigger the corresponding warning or control strategy.

[0007] The preset control conditions include: When the actual available visibility is greater than the braking visibility and the safety margin is lower than the first threshold, a deceleration warning is issued. The first threshold is the preset safety margin warning threshold.

[0008] The preset control conditions include: When the actual available visibility is less than or equal to the braking visibility, an enhanced warning signal is issued and the vehicle's longitudinal control system is activated to adjust the target speed and / or automatically apply the brakes.

[0009] The preset control conditions include: When the effective deceleration is less than the preset second threshold, the output braking capacity is insufficient and the emergency control strategy is triggered. The second threshold is the preset effective deceleration safety lower limit threshold.

[0010] The vehicle status data includes current vehicle speed, total vehicle mass, braking command or braking pressure, longitudinal acceleration, wheel speed and axle load information collected through onboard sensors and onboard communication interfaces, as well as vehicle longitudinal tilt angle obtained based on the onboard inertial measurement unit.

[0011] The effective deceleration is: ; In the formula, This represents the component of gravity along the direction of travel for the vehicle when it is on a slope. This represents the deceleration corresponding to the maximum braking force caused by road friction. This is an estimated value for braking efficiency. For the effective slope, take It indicates an uphill slope; a downhill slope would be negative.

[0012] The braking sight distance is: ; In the formula, This is the quality correction factor. For vehicle speed, This is an estimated value for the road surface adhesion coefficient. This is an estimated value for braking efficiency. For effective slope, For driver reaction time, This is a safety margin item.

[0013] The longitudinal tilt angle of the vehicle is used as the first observation, and the road slope information obtained based on satellite positioning and digital elevation model and / or electronic map is used as the second observation. Kalman filtering, extended Kalman filtering or equivalent state estimation algorithm is used to filter and compensate the slope state, and output a smooth effective slope angle or equivalent slope percentage.

[0014] The second aspect of this application provides a control system for a truck braking system, applicable to a control method for a truck braking system as shown in the first aspect, comprising: The vehicle sensor interface module is used to connect with vehicle speed sensors, brake pressure sensors or brake pedal opening sensors, longitudinal acceleration sensors, wheel speed sensors, axle load sensors and environmental perception sensors to obtain current vehicle speed, total vehicle mass, braking command or braking pressure, longitudinal acceleration, wheel speed, axle load information and external environmental information. Inertial measurement unit interface module, used to acquire the vehicle's longitudinal tilt angle; The satellite positioning and map information interface module is used to obtain vehicle location information based on satellite positioning and query digital elevation models and / or electronic maps to obtain road slope information at the vehicle's location. The road surface and environment perception module is used to receive outputs from cameras, rain sensors, temperature and humidity sensors and / or road surface condition recognition algorithms to identify the road surface conditions such as dry, slippery, snow or ice, as well as environmental conditions such as weather and sunlight. The slope fusion module is used to fuse longitudinal inclination angle and road slope information from multiple sources to obtain the effective slope angle or equivalent slope percentage of the current vehicle location. The adhesion coefficient and braking efficiency estimation module is used to estimate the road adhesion coefficient and braking efficiency online when the vehicle is in braking condition, based on the relationship between vehicle speed change, wheel speed and longitudinal acceleration and braking command or braking pressure, and output the road adhesion coefficient estimate and braking efficiency estimate respectively. The mass correction coefficient determination module is used to call a pre-established mass correction function based on the current total vehicle mass M and / or axle load distribution to obtain the mass correction coefficient corresponding to the current load condition. The braking sight distance calculation module is used to calculate the effective deceleration and braking distance of the vehicle on the slope section based on the effective slope angle, the estimated value of the output road surface adhesion coefficient and the estimated value of braking efficiency, calculate the reaction distance based on the preset or estimated driver reaction time, and determine the safety margin based on the environment and road conditions, so as to obtain the final braking sight distance. The visibility comparison and risk assessment module is used to obtain the actual available visibility or effective detection distance in front of the vehicle and compare it with the braking visibility distance. The human-machine interaction module is used to issue a deceleration warning to the driver when the safety margin is insufficient, and to issue an enhanced warning when a braking safety risk is determined to exist. The longitudinal control linkage module is used to link the vehicle's longitudinal control system to adjust the target vehicle speed and / or automatically apply braking when a braking safety risk is determined. When the effective deceleration is less than a preset second threshold, it outputs a warning of insufficient braking capacity and triggers an emergency control strategy.

[0015] The braking sight distance calculation module is configured as follows: When the detected environmental conditions are rain, snow, fog, low light at night, slippery road surface, snow accumulation or ice, the safety margin is increased based on the environmental level output by the road surface and environment perception module. When complex road scenarios such as long downhill slopes, continuous curves, ramp entrances or exits are detected ahead, the safety margin is further increased. The safety margin term for calculating braking sight distance is formed by superimposing the safety additional distances corresponding to the above environmental conditions and road conditions.

[0016] The technical solution provided in this application may include the following beneficial effects: This application provides a control method and system for truck braking systems. Based on vehicle longitudinal dynamics, this method introduces effective slope angle, road surface adhesion coefficient estimates, braking efficiency estimates, and a mass correction function. It proposes a unified formula for calculating effective deceleration and braking distance, and combines this with driver reaction distance and safety margin terms to form the final braking sight distance. Through this framework, consistent and comparable quantitative indicators of braking sight distance can be obtained under different slopes, loads, and road surface conditions, overcoming the shortcomings of existing technologies that rely on experience-based safe following distances or collision time thresholds. The method significantly improves slope estimation accuracy through multi-source slope fusion, allowing for a refined quantification of the impact of slope on braking sight distance, fundamentally enhancing the weight and accuracy of slope in braking safety assessment. During actual vehicle braking, this method estimates the road surface adhesion coefficient and braking efficiency online. Compared to traditional methods that only use calibration values ​​or simple table lookups, it can reflect the real-time impact of current road conditions, braking system temperature, and wear on actual braking performance, establishing the braking sight distance based on the vehicle's current true braking capacity, thereby significantly improving the reliability and relevance of risk assessment. By introducing a mass correction function, greater braking distance and braking sight distance are achieved under heavy-load conditions at the same speed and on the same road surface. This method uses braking sight distance as the core indicator to directly drive the vehicle's longitudinal control and warning strategies, tightly coupling the longitudinal control decisions of ACC / AEB with the vehicle's actual braking capacity, significantly improving the system's adaptability and safety on complex sloping roads and inclement road conditions.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0018] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0019] Figure 1 This is a schematic flowchart illustrating a control method for a truck braking system according to an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of the structure of a control system for a truck braking system shown in an embodiment of this application. Detailed Implementation

[0021] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0022] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0023] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0026] like Figure 1 A control method for a truck braking system, as shown, includes the following steps: S1. Obtain vehicle status data and environmental data, and estimate the road adhesion coefficient, braking efficiency, and mass correction coefficient.

[0027] Vehicle status data includes: Current vehicle speed is based on speed sensors installed on the transmission output shaft or wheels; The total vehicle mass is estimated based on onboard axle load sensors, air suspension pressure sensors, and / or vehicle-to-everything (V2X) communication interfaces. Braking command or braking pressure, including brake pedal opening, master cylinder pressure and / or brake air pressure of each axle; Longitudinal acceleration is provided by the vehicle's inertial measurement unit (IMU) or a separate longitudinal acceleration sensor; Wheel speed is used to determine tire adhesion and wheel slippage. The vehicle's longitudinal tilt angle is calculated from the attitude angle information output by the IMU.

[0028] Environmental data includes: Road slope information is obtained by using the GNSS satellite positioning module to acquire the vehicle's current location and then querying the corresponding road slope percentage in the electronic map or digital elevation model. Road condition information, including dryness, slipperiness, snow accumulation, and icing, is obtained from vehicle-mounted cameras, rain sensors, temperature / humidity sensors, etc. Road condition information, through navigation map and vehicle positioning information, determines whether the current road is a complex road scenario such as a long downhill slope, continuous curves, ramp entrance or exit, or ordinary straight road section.

[0029] Based on the above vehicle condition data and environmental data, the road surface adhesion coefficient, braking efficiency, and mass correction coefficient are estimated: When a braking command or braking pressure exceeds a preset value, and the vehicle speed V is higher than the minimum estimated vehicle speed, the on-board controller calculates the theoretical braking force and the corresponding theoretical deceleration based on the braking pressure and the braking system characteristic model. : When a vehicle is on a slope, the component of gravity along the direction of travel is: If going uphill (the vehicle is going uphill and braking), this component is beneficial for deceleration; if going downhill, it has a negative effect. Considering the maximum braking force caused by road friction, the deceleration corresponding to this component is approximately... (multiplied by braking efficiency) (characterizing the actual usable braking deceleration), then the theoretical deceleration It can be written as: ; In the formula, take Indicates uphill (aiding braking); a negative value indicates downhill (e.g., downhill). ,correspond If only the slope percentage G% is known, an approximation can be used. (This approximation is very good when the slope is small, <10%).

[0030] Theoretical deceleration Compared with the actual measured longitudinal acceleration By comparison, and using methods such as recursive least squares and / or Kalman filtering, the estimated value of the road adhesion coefficient is obtained online. .by and Using the deviation as input, a braking efficiency estimation model is constructed to obtain the braking efficiency estimate. It is used to reflect changes in braking performance caused by factors such as brake temperature, brake fade, and wear.

[0031] Based on the vehicle's total mass M, a mass correction factor k(M) is calculated to correct for actual braking performance under different load conditions. Mass correction factor: ; In the formula, As a standard benchmark for truck weight, The empirical adjustment coefficient (0.2–0.5) is used to fit the experimental results.

[0032] Among them, the vehicle controller retains the most recently updated information when not braking. and It can gradually regress to the nominal value according to a preset strategy to improve the stability of the estimation.

[0033] S2. Based on the vehicle's longitudinal tilt angle and road slope information, generate an effective slope angle or equivalent slope percentage, and calculate the vehicle's effective deceleration and braking sight distance on the sloping road section. The braking sight distance results include braking distance, reaction distance, safety margin term, and braking sight distance. The safety margin term is determined in combination with the environment and road conditions.

[0034] To verify the impact of slope, specifically, the sight distance for the same truck going uphill at 2% and downhill at 4% was calculated (no extra margin was added here for easy comparison): A uphill slope of 2% Convert the slope percentage to approximation: Calculate the quality correction factor : Speed ​​conversion : Calculate the effective factors in the denominator : Calculate braking distance : Calculate reaction distance : Multiply by quality correction factor Calculate sight distance: Output: Line of sight length approximately 116.2 meters.

[0035] B (4% downhill): Same as above, 1.25 Same as above Braking distance The reaction distance is the same as above: 26.67m Calculate sight distance by multiplying by a quality factor: Output: The buffer length is approximately 131.7 meters.

[0036] Comparison of sight distances A and B: The recommended sight distance for uphill (2%) is about 116.2m; it increases significantly to 131.7m for downhill (4%), indicating that the slope has a significant impact, especially the downhill section where a longer sight distance is required.

[0037] Calculation of effective slope angle or equivalent slope percentage: The longitudinal tilt angle output by the IMU is fused with the slope percentage obtained from the electronic map query to construct a state-space model with the slope angle as the state variable. Using the longitudinal tilt angle and slope percentage as observations, an extended Kalman filter or equivalent filter method is employed to dynamically estimate the slope angle, resulting in a smooth and effective slope angle. When the slope is small, an approximate relationship can be used. The effective slope angle Converted to an equivalent slope percentage or its sine value for subsequent longitudinal dynamics calculations.

[0038] Effective deceleration calculation: The onboard controller calculates the effective deceleration of the vehicle on a sloping road section based on gravitational acceleration, estimated road surface adhesion coefficient, estimated braking efficiency, and effective gradient. ; In the formula, This represents the component of gravity along the direction of travel for the vehicle when it is on a slope. This represents the deceleration corresponding to the maximum braking force caused by road friction. This is an estimated value for braking efficiency. For the effective slope, take It indicates an uphill slope; a downhill slope would be negative.

[0039] exist Under the premise of effectiveness, the on-board controller calculates the braking distance, reaction distance, safety margin, and final braking sight distance on the slope: (1) The braking distance S (excluding the reaction distance) is obtained from the energy method or the formula for uniformly decelerated motion: ; Bundle If the unit is km / h, you need to divide by 3.6 to get m / s.

[0040] (2) The vehicle controller can calculate the reaction distance based on the preset driver reaction time t, or by estimating the current reaction time t in combination with the driver's historical operation characteristics. : ; t can be conservatively taken as t=1.2s or higher.

[0041] (3) The on-board controller determines the safety margin item in combination with the environment and road conditions. : When the road surface is wet, snowy, or icy, the corresponding additional safety distance is added to the preset additional safety distance. When the weather conditions are rainy, snowy, foggy, and / or the lighting conditions are at night, the corresponding additional safety distance is further increased; when the road conditions are complex road scenarios such as long downhill slopes, continuous curves, ramp entrances or exits, additional distances are added to the sloping or curved sections according to preset rules; finally, the various additional safety distances corresponding to the above environmental and road conditions are superimposed to form a safety margin term used for braking sight distance calculation. . Additional safety margin (fixed meters or percentage, e.g., 515%) is provided to account for model errors and unforeseen factors on site.

[0042] (4) The on-board controller combines the braking distance, reaction distance, and safety margin to obtain the braking sight distance length L: .

[0043] L is the minimum safe sight distance required by the vehicle under the current slope, load, road surface conditions and environmental conditions.

[0044] S3. Obtain the actual available line of sight in front of the vehicle, compare the actual available line of sight with the braking line of sight in real time, and generate a comparison result. The actual available line of sight is collected based on the on-board sensing equipment.

[0045] The vehicle-mounted sensing equipment includes at least one forward-facing sensing sensor, such as a forward-facing millimeter-wave radar, lidar, and / or a forward-facing camera, for detecting objects ahead, road boundaries, or visibility limits. Based on the aforementioned sensing data, the vehicle controller calculates the actual available line-of-sight ahead of the vehicle. The visibility distance can be the distance between the vehicle and the target vehicle or obstacle ahead, or the distance from the vehicle to the end of the observable road or the limit of visibility.

[0046] During each control cycle, the on-board controller will The comparison is performed with the braking sight distance L to generate a comparison result, and the safety margin can be further calculated. The difference between the current value and the preset threshold.

[0047] S4. Determine whether the comparison result and / or effective deceleration meet at least one preset control condition. If so, trigger the corresponding warning or control strategy.

[0048] Preset control conditions include: When the actual available visibility is greater than the braking visibility and the safety margin is lower than the first threshold, a deceleration warning is issued. The first threshold is a preset warning threshold for the safety margin. At this time, the vehicle controller determines that the current visibility still meets the basic safety requirements, but the safety margin is too low. It then issues a deceleration warning to the driver through the human-machine interface, such as displaying corresponding icons or text information on the instrument panel, or prompting the driver to decelerate through sound to increase the safety margin.

[0049] When the actual available visibility is less than or equal to the braking visibility, an enhanced warning signal is issued and the vehicle's longitudinal control system is activated to adjust the target speed and / or automatically apply the brakes. At this time, the onboard controller determines that there is a potential braking safety risk and issues an enhanced warning signal to the driver, such as using a higher-priority audible alarm, flashing warning, or steering wheel / seat vibration; at the same time, it activates the vehicle's longitudinal control system (such as the ACC / AEB system) to automatically adjust the target speed and / or automatically apply the brakes, so that the vehicle can be reduced to a safe speed as soon as possible or decelerated in a controlled manner within the available distance.

[0050] When the effective deceleration is less than a preset second threshold, an insufficient braking capacity warning is issued and an emergency control strategy is triggered. The second threshold is the preset lower limit of effective deceleration safety. At this time, the vehicle controller believes that the maximum available deceleration of the vehicle under the current slope, road surface, and load conditions is insufficient to meet safety requirements, and immediately issues an insufficient braking capacity warning and triggers an emergency control strategy, such as: advising the driver to decelerate as soon as possible or move into an escape lane; implementing stronger braking by combining engine braking, retarder, and wheel braking systems; and restricting vehicle acceleration requests when necessary.

[0051] A control system for a truck braking system, applicable to the control method for a truck braking system as described above, includes: The vehicle sensor interface module is used to connect with vehicle speed sensors, brake pressure sensors or brake pedal opening sensors, longitudinal acceleration sensors, wheel speed sensors, axle load sensors and environmental perception sensors to obtain current vehicle speed, total vehicle mass, braking command or braking pressure, longitudinal acceleration, wheel speed, axle load information and external environmental information. Inertial measurement unit interface module, used to acquire the vehicle's longitudinal tilt angle; The satellite positioning and map information interface module is used to obtain vehicle location information based on satellite positioning and query digital elevation models and / or electronic maps to obtain road slope information at the vehicle's location. The road surface and environment perception module is used to receive outputs from cameras, rain sensors, temperature and humidity sensors and / or road surface condition recognition algorithms to identify the road surface conditions such as dry, slippery, snow or ice, as well as environmental conditions such as weather and sunlight. The slope fusion module is used to fuse longitudinal inclination angle and road slope information from multiple sources to obtain the effective slope angle or equivalent slope percentage of the current vehicle location. The adhesion coefficient and braking efficiency estimation module is used to estimate the road adhesion coefficient and braking efficiency online when the vehicle is in braking condition, based on the relationship between vehicle speed change, wheel speed and longitudinal acceleration and braking command or braking pressure, and output the road adhesion coefficient estimate and braking efficiency estimate respectively. The mass correction coefficient determination module is used to call a pre-established mass correction function based on the current total vehicle mass M and / or axle load distribution to obtain the mass correction coefficient corresponding to the current load condition. The braking sight distance calculation module is used to calculate the effective deceleration and braking distance of the vehicle on the slope section based on the effective slope angle, the estimated value of the output road surface adhesion coefficient and the estimated value of braking efficiency, calculate the reaction distance based on the preset or estimated driver reaction time, and determine the safety margin based on the environment and road conditions, so as to obtain the final braking sight distance. The visibility comparison and risk assessment module is used to obtain the actual available visibility or effective detection distance in front of the vehicle and compare it with the braking visibility distance. The human-machine interaction module is used to issue a deceleration warning to the driver when the safety margin is insufficient, and to issue an enhanced warning when a braking safety risk is determined to exist. The longitudinal control linkage module is used to link the vehicle's longitudinal control system to adjust the target vehicle speed and / or automatically apply braking when a braking safety risk is determined. When the effective deceleration is less than a preset second threshold, it outputs a warning of insufficient braking capacity and triggers an emergency control strategy.

[0052] The braking sight distance calculation module is configured as follows: When the detected environmental conditions are rain, snow, fog, low light at night, slippery road surface, snow accumulation or ice, the safety margin is increased based on the environmental level output by the road surface and environment perception module. When complex road scenarios such as long downhill slopes, continuous curves, ramp entrances or exits are detected ahead, the safety margin is further increased. The safety margin term for calculating braking sight distance is formed by superimposing the safety additional distances corresponding to the above environmental conditions and road conditions.

[0053] Finally, it should be noted that in this document, relationships such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "include," "contain," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0054] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0055] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A control method for a truck brake system, characterized by, The method comprises the following steps: Obtain vehicle state data and environment data, estimate the road adhesion coefficient estimate value, brake efficiency estimate value and mass correction coefficient, the vehicle state data includes vehicle longitudinal inclination, the environment data includes road slope information and road surface state; Generate effective slope angle or equivalent slope percentage based on the vehicle longitudinal inclination and the road slope information, calculate the effective deceleration of the vehicle on the slope road section and the braking sight distance result, the braking sight distance result includes braking distance, reaction distance, safety margin term and braking sight distance, the safety margin term is determined in combination with the environment and road working condition; Obtain the actual available sight distance in front of the vehicle, real-time compare the actual available sight distance with the braking sight distance, generate comparison result, the actual available sight distance is obtained based on the vehicle-mounted perception device; Determine whether the comparison result and / or the effective deceleration meets at least one preset control condition, if yes, trigger the corresponding early warning or control strategy.

2. The control method for the truck braking system according to claim 1, wherein the preset control condition comprises: When the actual available sight distance is greater than the braking sight distance and the safety margin term is lower than a first threshold value, a deceleration prompt is sent, and the first threshold value is a preset safety margin term early warning threshold value.

3. The control method for the truck braking system according to claim 1, wherein the preset control condition comprises: When the actual available sight distance is less than or equal to the braking sight distance, an enhanced early warning signal is sent and the vehicle longitudinal control system is linked to adjust the target vehicle speed and / or automatically apply the brake.

4. The control method for the truck braking system according to claim 1, wherein the preset control condition comprises: When the effective deceleration is less than a preset second threshold value, a brake capacity insufficient prompt is output and an emergency control strategy is triggered, and the second threshold value is a preset effective deceleration safety lower limit threshold value. The vehicle state data includes the current vehicle speed, vehicle total mass, brake instruction or brake pressure, longitudinal acceleration, wheel speed and axle load information collected through the vehicle-mounted sensor and vehicle-mounted communication interface, and the vehicle longitudinal inclination obtained based on the vehicle-mounted inertial measurement unit. The effective deceleration is: The length of the sight distance of the braking sight distance is:

5. The control method for a truck brake system according to claim 1, characterized by, 8. The control method for the truck braking system according to claim 1, wherein the vehicle longitudinal inclination is taken as a first observation, the road slope information obtained based on satellite positioning and digital elevation model and / or electronic map is taken as a second observation, the Kalman filtering, extended Kalman filtering or equivalent state estimation algorithm is used to filter and compensate the slope state, and the smooth effective slope angle or equivalent slope percentage is output.

6. The control method for a truck brake system according to claim 1, wherein The method comprises the following steps: ； wherein is the component of gravity in the direction of travel of the vehicle when there is a slope, is the maximum deceleration corresponding to the maximum braking force caused by the road surface friction, is the braking efficiency estimate, is the effective slope, taken as is positive if the slope is uphill, and negative if it is downhill.

7. The control method for a truck brake system according to claim 1, characterized by, The vehicle-mounted sensor interface module is used to connect with the vehicle speed sensor, brake pressure sensor or brake pedal opening degree sensor, longitudinal acceleration sensor, wheel speed sensor, axle load sensor and environment perception sensor to obtain the current vehicle speed, vehicle total mass, brake instruction or brake pressure, longitudinal acceleration, wheel speed, axle load information and external environment information. ； wherein is a mass correction factor, is a vehicle speed, is a road surface adhesion coefficient estimate, is a braking efficiency estimate, is an effective slope, is a driver reaction time, is a safety margin term. ​ ​ 9. A control system for a freight car braking system adapted to be used in a control method for a freight car braking system as claimed in any one of claims 1-8, characterized by ​ ​ an inertial measurement unit interface module configured to obtain a vehicle longitudinal inclination angle; a satellite positioning and map information interface module configured to obtain satellite positioning based vehicle position information and to query a digital elevation model and / or an electronic map to obtain road slope information at the vehicle's location; a road and environment perception module configured to receive outputs from a camera, a rain sensor, a temperature and humidity sensor, and / or a road surface state recognition algorithm to identify road surface dry, wet, snowy, or icy conditions and weather, lighting, and environmental working conditions; a slope fusion module configured to perform multi-source fusion of the longitudinal inclination angle and the road slope information to obtain an effective slope angle or an equivalent slope percentage at the vehicle's current location; an adhesion coefficient and braking efficiency estimation module configured to estimate road adhesion coefficient and braking efficiency online based on vehicle speed change, wheel speed, and longitudinal acceleration and the relationship between the braking instruction or the brake pressure when the vehicle is in a braking working condition, and to output a road adhesion coefficient estimate and a braking efficiency estimate, respectively; a mass correction coefficient determination module configured to call a pre-established mass correction function according to the current vehicle total mass M and / or axle load distribution to obtain a mass correction coefficient corresponding to the current load working condition; a braking sight distance calculation module configured to calculate the effective deceleration and braking distance of the vehicle on a sloping road section according to the effective slope angle, the output road adhesion coefficient estimate, and the braking efficiency estimate, to calculate a reaction distance according to a preset or estimated driver reaction time, to determine a safety margin term based on environmental and road working conditions, and to obtain a final braking sight distance; a sight distance comparison and risk assessment module configured to obtain the actual available sight distance or effective detection distance in front of the vehicle and compare it with the braking sight distance; a human-machine interaction module configured to issue a speed reduction prompt to the driver when the safety margin term is insufficient and to issue an enhanced warning when a braking safety risk is determined to exist; a longitudinal control linkage module configured to link the vehicle longitudinal control system to adjust the target vehicle speed and / or to automatically apply braking when a braking safety risk is determined to exist, to output a braking capacity insufficient prompt and to trigger an emergency control strategy when the effective deceleration is less than a preset second threshold.

10. A control system for a truck braking system according to claim 9, characterized in that, The braking sight distance calculation module is configured to: when detecting that the environmental working condition is rainy, snowy, foggy, night low illumination, wet, snowy, or icy road surface, increase the safety margin based on the environmental level output by the road and environment perception module; when detecting that the front is a complex road scene of a long and large downhill, a continuous curve, an on-ramp or off-ramp entrance, further increase the safety margin; superimpose the safety additional distance corresponding to the above environmental working conditions and road working conditions to form the safety margin term used to calculate the braking sight distance.

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