Vehicle braking force determination method and device, vehicle and medium

Abstract

The invention relates to the technical field of braking systems, and discloses a vehicle braking force determining method and device, a vehicle and a medium. Determining a target pedal travel based on the pedal travel signal; the temperatures of all brake discs, the depths of brake pedals, the activation states of the anti-lock braking system and the current braking force fed back by the braking executing mechanism in real time are obtained, and heat fading analysis is conducted on the braking executing mechanism based on the temperatures of all the brake discs, the depths of the brake pedals, the activation states of the anti-lock braking system and the current braking force; obtaining a heat fading analysis result; and in response to a current brake pedal feeling determined by the driver, determining a target braking force corresponding to the target pedal travel based on the current brake pedal feeling and the heat fading analysis result. The multi-dimensional parameters are adopted for heat fading analysis, different driver operation habits are adapted, accurate recognition of the braking force is facilitated, and the user experience is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of braking systems, in particular to a vehicle braking force determination method and device, vehicle and medium. BACKGROUND

[0002] The braking system is an important guarantee for safe driving of the automobile. With the development of automobile electrification and intelligentization, higher requirements are put forward for the braking system, i.e. faster pressure building response, higher control accuracy requirement and even higher energy recovery rate. All the above requirements continuously promote the development of the brake-by-wire technology.

[0003] At present, as a commonly used brake-by-wire system, the EMB (Electro-Mechanical Brake) mainly consists of a brake pedal simulation sensor, an EMB actuator and a controller. For the recognition of the braking intention of the driver, the existing technology usually converts the pedal stroke collected by the pedal stroke sensor into the corresponding braking force. However, the brake pedal in the existing EMB system does not provide a foot feeling (also known as brake pedal feeling, i.e. the pedal feedback force determined by the driver operating the brake pedal), so that the driver is easy to step the pedal too deep, thereby causing a braking force feedback that is not the real demand of the driver. In addition, the braking performance of the vehicle is easily affected by its hardware components, such as the over-high temperature of the brake disc which will directly lead to the thermal recession of the braking performance of the vehicle. The direct acquisition of the corresponding braking force from the pedal stroke cannot truly reflect the braking demand of the driver, which not only seriously affects the user experience, but also may bring great driving safety risk to the vehicle.

[0004] Therefore, there is an urgent need for a vehicle braking force determination scheme to ensure the accuracy, safety and reasonableness of the acquired braking force, so as to meet the braking demand of the vehicle and improve the driving experience of the user. SUMMARY

[0005] Therefore, the present application provides a vehicle braking force determination method, device, vehicle and medium to solve the problem that the existing technology cannot accurately recognize the vehicle braking force, which leads to the inability to meet the high-precision braking demand and thus seriously affects the driving experience of the user.

[0006] In a first aspect, the present application provides a vehicle braking force determination method, which comprises:

[0007] acquiring a pedal stroke signal collected by a pedal stroke sensor;

[0008] determining a target pedal stroke based on the pedal stroke signal;

[0009] acquire all brake disc temperatures, brake pedal depths, anti-lock braking system activation states, and current braking forces fed back by brake actuators in real time, and perform thermal fade analysis on the brake actuators based on all the brake disc temperatures, brake pedal depths, anti-lock braking system activation states, and current braking forces to obtain thermal fade analysis results;

[0010] In response to a current brake pedal feeling determined by a driver, and based on the current brake pedal feeling and the thermal fade analysis results, a target braking force corresponding to a target pedal stroke is determined.

[0011] The present application uses multi-dimensional parameters for thermal fade analysis, which can cover thermal fade scenarios under different braking conditions to achieve comprehensive and accurate identification of thermal fade, and then adjust the braking force in real time based on the thermal fade analysis results, which can ensure accurate identification of the braking force subsequently. At the same time, in response to the current brake pedal feeling determined by the driver, it can adapt to the operation habits and preferences of different drivers, thereby improving the user experience. And based on the current brake pedal feeling and the thermal fade analysis results, the target braking force corresponding to the target pedal stroke is determined, which not only ensures the safety, accuracy and reliability of the braking force acquisition, truly reflects the driver's braking demand, but also ensures the safety of the vehicle braking, greatly meeting the user's safe driving needs.

[0012] In an optional embodiment, the thermal fade analysis on the brake actuators based on all the brake disc temperatures, brake pedal depths, anti-lock braking system activation states, and current braking forces to obtain thermal fade analysis results includes:

[0013] If any brake disc temperature exceeds a preset temperature threshold and lasts for a first preset time;

[0014] Or, when the brake pedal depth exceeds a preset depth threshold and lasts for a second preset time, the anti-lock braking system is in an inactive state;

[0015] Or, when the anti-lock braking system is in an active state, the current braking force exceeds a preset braking force threshold, it is determined that the thermal fade analysis result is thermal fade.

[0016] The present application performs thermal fade analysis by designing three different dimensions of judgment conditions, i.e. brake disc temperature, brake pedal depth and anti-lock braking system state combination, and braking force when the anti-lock braking system is in an active state, which can comprehensively cover various typical working conditions of the brake actuators that may produce thermal fade, thereby ensuring that thermal fade under different braking scenarios can be effectively captured, not only improving the effectiveness and safety of thermal fade identification, but also providing an accurate basis for subsequent braking force adjustment, such as releasing the maximum clamping force, greatly ensuring the stable operation of the braking system.

[0017] In an alternative embodiment, the vehicle brake force determination method further comprises:

[0018] If all brake disc temperatures do not exceed the preset temperature threshold, or there is a brake disc temperature exceeding the preset temperature threshold and not lasting for a first preset time;

[0019] And the brake pedal depth does not exceed the preset depth threshold, or the brake pedal depth exceeds the preset depth threshold and does not last for a second preset time, or the brake pedal depth exceeds the preset depth threshold and lasts for a second preset time, the anti-lock braking system is in an activated state;

[0020] And when the anti-lock braking system is in the activated state, if the current brake force does not exceed the preset brake force threshold, the heat fade analysis result is determined to be no heat fade.

[0021] The application also considers the judgment process of no heat fade, by accurately defining the non-heat fade boundary condition, refining the constraint to avoid misjudgment, and forming a logical closed loop with the heat fade judgment, while ensuring braking safety, maintaining the stability and rationality of brake force output under normal working conditions, and taking into account reliability and driving experience.

[0022] In an alternative embodiment, when the heat fade analysis result is no heat fade, based on the current brake pedal feeling and the heat fade analysis result, the target brake force corresponding to the target pedal stroke is determined, comprising:

[0023] Determine a first target curve based on the current brake pedal feeling;

[0024] Find the corresponding target brake force from the first target curve based on the target pedal stroke; wherein the first target curve is a mapping curve of different brake pedal strokes and vehicle brake forces.

[0025] When the heat fade analysis result is no heat fade, the application selects the corresponding first target curve based on the current brake pedal feeling determined by the driver, so that the mapping relationship between brake pedal stroke and brake force adapts to the operation preferences of different drivers, such as habits of corresponding relationship between pedal depth and brake force. Since different drivers can choose the appropriate pedal feeling according to their driving style, the brake response can be made more in line with the driver's expectations by outputting the brake force through the corresponding first target curve, which significantly improves driving comfort and handling experience.

[0026] In an alternative embodiment, when the heat fade analysis result is heat fade, based on the current brake pedal feeling and the heat fade analysis result, the target brake force corresponding to the target pedal stroke is determined, comprising:

[0027] Determine a first target curve and a second target curve based on the current brake pedal feeling, respectively;

[0028] finding the first brake force from the first target curve and the second brake force from the second target curve based on the target pedal stroke;

[0029] summing the first brake force and the first brake force to obtain a target brake force corresponding to the target pedal stroke; wherein the second target curve is a mapping curve of different brake pedal strokes and compensation brake forces.

[0030] When the thermal decay analysis result is that thermal decay occurs, the present application considers that thermal decay will cause the actual brake force of the brake actuator to decrease, and specially designs the second target curve to compensate for the brake force loss caused by thermal decay, that is, by summing the first brake force of the first target curve and the second brake force of the second target curve, the brake force output can be specifically increased when thermal decay occurs, so as to ensure that even if the performance of the actuator decays, sufficient brake force can still be provided to meet the brake demand of the driver, effectively avoiding the safety risks of insufficient brake force and extended brake distance caused by thermal decay, and greatly ensuring the brake effectiveness in extreme working conditions.

[0031] In an optional embodiment, the determination process of the first target curve and the second target curve comprises:

[0032] calculating a basic brake force stroke curve based on the relationship among the vehicle brake force, the vehicle mass and the vehicle acceleration, and calibrating and correcting the basic brake force stroke curve according to the actuator parameters to obtain the first target curve;

[0033] determining a thermal decay brake compensation curve based on preset configuration requirements, and calibrating and correcting the thermal decay brake compensation curve according to the actuator parameters to obtain the second target curve; wherein the preset configuration requirements include that when the brake pedal stroke reaches the maximum value, the compensation brake force outputting the maximum clamping force of the brake actuator is released, and the brake force corresponding to each brake pedal stroke is compensated at a preset proportion.

[0034] The curve determination process of the present application combines theory with practice, designs unified logic, reduces complexity and improves expandability, ensures that the first target curve and the second target curve can accurately match brake demand and hardware capability, and efficiently applies to provide a reliable curve basis for the accurate output of brake force in various actual working conditions.

[0035] In an optional embodiment, the target pedal stroke is determined based on the pedal stroke signal, comprising:

[0036] calculating a stroke error based on the pedal stroke signal;

[0037] if the stroke error is greater than a preset threshold and lasts for a third preset time, reporting a vehicle fault and limiting the output of the vehicle brake force.

[0038] If the stroke error is not greater than the preset threshold value, or the stroke error is greater than the preset threshold value and does not last for the third preset time, a stroke average is calculated based on the pedal stroke signal, and the stroke average is determined as the target pedal stroke.

[0039] The application calculates the stroke error based on the pedal stroke signal, like the deviation of two signals of a sensor, and judges the signal validity in combination with the double conditions that the error is greater than the threshold value and lasts for the third preset time, so as to improve the signal reliability and effectively avoid the risk of misjudgment; and when the pedal stroke signal is reliable, the target pedal stroke is determined by calculating the stroke average, so that the target stroke is more stable and closer to the real braking intention of the driver.

[0040] In an optional embodiment, before determining the target pedal stroke based on the pedal stroke signal, the vehicle braking force determination method further comprises:

[0041] judging whether the pedal stroke signal is valid;

[0042] when the pedal stroke signal is valid, performing the step of determining the target pedal stroke based on the pedal stroke signal;

[0043] when the pedal stroke signal is invalid, returning to perform the step of obtaining the pedal stroke signal collected by the pedal stroke sensor.

[0044] The application can filter out invalid signals in advance by judging the signal validity before determining the target pedal stroke, so as to ensure that all signals entering the subsequent target pedal stroke determination step are reliable signals; the target stroke calculation error caused by invalid signals can be avoided from the source, so as to prevent the deviation of the braking force output from the real intention of the driver, and the accuracy of braking intention recognition and the braking safety can be significantly improved.

[0045] In a second aspect, the application provides a vehicle braking force determination device, which comprises:

[0046] a signal acquisition module for acquiring the pedal stroke signal collected by the pedal stroke sensor;

[0047] a stroke determination module for determining the target pedal stroke based on the pedal stroke signal;

[0048] a thermal decay analysis module for acquiring all brake disc temperatures, brake pedal depths, activation states of anti-lock braking systems and current braking forces fed back by braking actuators in real time respectively, and performing thermal decay analysis on the braking actuators based on all brake disc temperatures, brake pedal depths, activation states of anti-lock braking systems and current braking forces, to obtain a thermal decay analysis result;

[0049] The braking force determination module is configured to determine a target braking force corresponding to a target pedal stroke in response to a current brake pedal feel determined by a driver and based on the current brake pedal feel and a thermal fade analysis result.

[0050] The vehicle braking force determination device of the present invention performs thermal decay analysis through multi-dimensional parameters and adapts to different drivers' operating habits. It determines the target braking force corresponding to the target pedal stroke based on the current brake pedal feel and the thermal decay analysis results. It not only achieves comprehensive and accurate identification of thermal decay, but also ensures the precise determination of braking force, helps to truly reflect the driver's braking needs, greatly improves the user experience, and effectively avoids vehicle driving safety risks.

[0051] In a third aspect, the present invention provides a vehicle, comprising a controller, the controller comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to execute a vehicle braking force determination method according to the first aspect or any corresponding embodiment thereof.

[0052] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute a vehicle braking force determination method according to the first aspect or any corresponding embodiment thereof.

[0053] The vehicle braking force determination method and device of the present invention, by utilizing multi-dimensional parameters for thermal decay analysis, can cover thermal decay scenarios under different braking conditions, thereby achieving comprehensive and accurate identification of thermal decay, and adjusting the braking force in real time based on the thermal decay analysis results, greatly ensuring the accurate identification of the braking force; at the same time, in order to adapt to the operating habits and preferences of different drivers, the target braking force corresponding to the target pedal stroke is determined based on the current brake pedal feel determined by the driver and the thermal decay analysis results, which can ensure the safe, accurate and reliable acquisition of the braking force, not only truly reflecting the driver's braking needs, but also ensuring the vehicle braking safety, thereby meeting the user's safe driving needs and greatly improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1 is a structural block diagram of an EMB system according to an embodiment of the present invention;

[0056] Figure 2 is a structural block diagram of another EMB system according to an embodiment of the present application;

[0057] Figure 3 is a flowchart of a vehicle braking force determination method according to an embodiment of the present application;

[0058] Figure 4 is a flowchart of another vehicle braking force determination method according to an embodiment of the present application;

[0059] Figure 5 is a flowchart of a vehicle braking force determination scheme;

[0060] Figure 6 is a structural block diagram of a vehicle braking force determination device according to an embodiment of the present application;

[0061] Figure 7 is a structural diagram of a controller of a vehicle according to an embodiment of the present application. DETAILED DESCRIPTION

[0062] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0063] It should be noted that the current brake-by-wire system mainly includes EHB (Electro-Hydraulic Brake) and EMB. The EHB replaces the vacuum booster in the traditional brake product, collects the pedal stroke through a pedal stroke sensor to convert into corresponding braking force, and then builds pressure through a motor, which can achieve decoupling to a certain extent. However, a large amount of brake fluid is still needed in the EHB, and the hydraulic control pipeline is relatively complex. The hydraulic pressure is also affected by the pipeline and the valve body when transmitted to the wheel end. Overall, the hydraulic control is relatively complex and not easy to integrate with other electronic control systems. The EMB mainly includes a brake pedal simulation sensor, an EMB actuator, a controller and the like. The EMB actuator is directly loaded on the wheel end, which saves the pipeline part and avoids the influence of the hydraulic system on the response speed, has faster response speed, simpler structure, more flexible control and higher control efficiency, realizes complete decoupling between the driver and the vehicle, and is a truly brake-by-wire system.

[0064] At present, the acquisition of the driver's braking intention by the EMB involves the brake pedal structure, brake pedal backup, pedal feel switching, actuator thermal recession and other contents, so there is no mature solution for how to safely and reasonably identify the driver's braking intention. For example, the brake pedal part in the existing EMB does not provide foot feel (i.e. pedal feedback force) according to the EHB condition, so it is easy to appear that the driver steps on the pedal too deeply, thereby causing a brake force feedback that is not the real demand of the driver. Or when the single-point failure of the pedal stroke sensor occurs, the pedal stroke cannot be obtained, at this time the EHB will be degraded into backup, and the brake pedal is directly connected to the master cylinder. Although the pedal stroke cannot be obtained, braking can still be performed by stepping on the pedal at this time, and there is no motor assistance. However, according to the arrangement scheme of the EMB, if the single-way brake pedal stroke fails, the braking request cannot be obtained at this time, and there is no backup braking condition. In addition, the interface between the current many upper software and the actuator is clamping force. When the actuator end appears thermal recession, the brake force converted by the clamping force will be insufficient, thereby causing the brake to not meet the driver's expectation, and seriously affecting the user experience. Therefore, the embodiment provides an EMB system and a vehicle braking force determination method based on the system. The method specifically adopts multi-dimensional parameters for thermal recession analysis and adapts to different driver operation habits, not only realizes comprehensive and accurate identification of thermal recession, but also guarantees accurate identification of the braking force, thereby improving the user experience.

[0065] In the embodiment, an EMB system is provided, Figure 1 is a structural block diagram of the EMB system according to the embodiment of the application, as Figure 1 shown, the EMB system comprises two controllers 101, a brake actuator 102 and two pedal stroke sensors 103; wherein one controller 101 is a main controller, and the other controller 101 is a redundant controller (also called a backup controller); the brake actuator 102 is connected to the two controllers 101 respectively; and the two controllers 101 are connected to different pedal stroke sensors 103 respectively.

[0066] It should be noted that in a vehicle's braking system, the controller is the "core decision-making and control unit," also known as the Electronic Control Unit (ECU), which receives and processes braking-related signals and outputs control commands. The brake actuator is the core execution component that converts control signals into actual braking force. Its core function is to receive control commands (such as target braking force, clamping force, and other signals) from a brake controller (such as an ECU) and apply braking friction to the wheels through mechanical, hydraulic, or electromechanical means, ultimately achieving vehicle deceleration, stopping, or stationary motion. The pedal travel sensor is a key component for detecting the driver's braking operation. It detects the displacement of the brake pedal and converts the mechanical travel into an electrical signal to reflect the driver's braking intention. In this embodiment, the specific types of each component in the EMB system are determined based on actual needs and are not specifically defined here.

[0067] In this embodiment, the two controllers 101 can communicate with each other in real time; each pedal travel sensor 103 can collect two signals, namely pedal travel signals. The specific collection of signals can be determined by referring to conventional signal transmission methods in the field.

[0068] In this embodiment, an EMB system is provided. Figure 2 is a structural block diagram of another EMB system according to an embodiment of the present invention; Figure 2 As shown, the EMB system includes: controller X, controller Y, pedal travel sensor A, pedal travel sensor B, central control screen and brake actuators corresponding to the four wheels of the vehicle, namely EMB actuator FL, EMB actuator FR, EMB actuator RL and EMB actuator RR.

[0069] It should be noted that FL is the abbreviation of "Front Left", FR is the abbreviation of "Front Right", RL is the abbreviation of "Rear Left", and RR is the abbreviation of "Rear Right"; EMB actuator FL represents the left front wheel electronic mechanical brake actuator, which is responsible for controlling the braking action of the left front wheel of the vehicle, EMB actuator FR represents the right front wheel electronic mechanical brake actuator, which is responsible for controlling the braking action of the right front wheel of the vehicle, EMB actuator RL represents the left rear wheel electronic mechanical brake actuator, which is responsible for controlling the braking action of the left rear wheel of the vehicle, and EMB actuator RR represents the right rear wheel electronic mechanical brake actuator, which is responsible for controlling the braking action of the right rear wheel of the vehicle.

[0070] In this embodiment, controller X serves as the primary controller for communication and control with the EMB actuator. Pedal travel sensor A is directly hardwired to controller X, and the two are connected via a CAN cable (CAN stands for "Controller Area Network"). Controller Y serves as the backup controller, and pedal travel sensor B is directly hardwired to controller Y. Controllers X and Y communicate in real time, providing real-time feedback to controller X. If controller X becomes unable to control the EMB actuator, controller Y takes over and controls the EMB actuator.

[0071] In addition, each pedal travel sensor in the EMB system of this embodiment outputs two independent pedal travel signals (such as pedal travel sensor A outputs A1 and A2, and pedal travel sensor B outputs B1 and B2), forming a "dual sensor + four-way signal" redundant design, which is used for signal mutual verification and reliability assurance, and provides basic data for subsequent vehicle braking force identification.

[0072] It should be noted that the EMB system of this embodiment also displays different brake pedal feelings through the central control screen, so that the driver can select the brake pedal feeling that suits his driving habits through the central control screen and transmit it to controller X and controller Y through the network.

[0073] It's important to note that brake pedal feel, or the sensation a driver experiences when depressing the brake pedal, is a crucial component of the driving experience. Specifically, since depressing the brake pedal is the first step in activating the EMB system, every driver has a familiar brake pedal feel. Brake system pedal feel is typically factory-set and non-adjustable, and the feel varies across vehicle models.

[0074] According to an embodiment of the present invention, based on the EMB system described in the above embodiment, a corresponding method embodiment for determining vehicle braking force is also provided, which is applied to the EMB system. It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system, such as a set of computer-executable instructions, and that although a logical order is shown in the flowcharts, in some cases, the steps shown or described may be executed in a different order than shown.

[0075] In this embodiment, a method for determining vehicle braking force is provided. Figure 3 FIG. 1 is a flow chart of a method for determining vehicle braking force according to an embodiment of the present invention. Figure 3 As shown, the process includes the following steps:

[0076] Step S301: Acquire a pedal stroke signal collected by a pedal stroke sensor.

[0077] It should be noted that the specific content of the pedal stroke sensor and the acquisition method of the pedal stroke signal can be referred to the foregoing, and will not be repeated here.

[0078] In step S302, the target pedal stroke is determined based on the pedal stroke signal.

[0079] In this embodiment, the target pedal stroke is obtained by analyzing the pedal stroke signal, and the specific analysis method can be known by referring to the conventional operation in the art.

[0080] In step S303, all brake disc temperatures, brake pedal depths, activation states of the anti-lock braking system, and current braking forces fed back by the brake actuator in real time are obtained respectively, and a thermal decay analysis is performed on the brake actuator based on all the brake disc temperatures, brake pedal depths, activation states of the anti-lock braking system, and current braking forces, to obtain a thermal decay analysis result.

[0081] It should be noted that thermal decay is a physical phenomenon that the friction force decreases and the braking force weakens due to high temperature when the braking system is under high load or continuous braking for a long time, which significantly affects driving safety. The brake disc temperature is the real-time temperature generated by the brake disc during braking due to frictional heating, which is collected in real time by a temperature sensor (such as a thermocouple or an infrared sensor) installed near the brake disc, reflecting the thermal load state of the brake disc: too high temperature will cause thermal decay, and thus reduce the braking efficiency. The brake pedal depth refers to the displacement of the brake pedal stepped down by the driver, which is collected in real time by a pedal stroke sensor (such as a Hall sensor or a resistance sensor), and can directly reflect the driver's braking intensity requirement, such as greater depth, indicating that the driver expects greater braking force. The activation state of the anti-lock braking system (ABS) refers to whether the ABS is in a working state, which is usually represented by a state quantity, such as “activated” (working) or “not activated” (hibernation); in the control system, it is usually recorded by a binary signal (such as 1 indicating activation and 0 indicating non-activation) or a state code (such as a specific identifier in a fault code). The current braking force fed back in real time by the brake actuator is the actual output braking force of the EMB actuator, which is collected and fed back to the controller in real time by a built-in force sensor (such as a strain gauge or a pressure sensor).

[0082] In step S304, the target pedal stroke corresponding to the target braking force is determined in response to the current brake pedal feeling determined by the driver and based on the current brake pedal feeling and the thermal decay analysis result.

[0083] In this embodiment, the driver selects the current brake pedal feeling through a visual operation interface, such as the central control screen of the vehicle.

[0084] The vehicle braking force determination method provided in the embodiment of the present application can cover the heat fade scene under different braking conditions by using multi-dimensional parameters for heat fade analysis, thereby realizing comprehensive and accurate identification of heat fade, and using the heat fade analysis result to adjust the braking force in real time, which helps to ensure accurate identification of the braking force. Meanwhile, in order to adapt to the operation habits and preferences of different drivers, the target braking force corresponding to the target pedal stroke is determined based on the current brake pedal feeling determined by the driver and the heat fade analysis result, which can ensure the safety, accuracy and reliability of the braking force acquisition, thereby truly reflecting the braking demand of the driver, ensuring the safety of the vehicle braking, meeting the safety driving demand of the user, and greatly improving the user experience.

[0085] A vehicle braking force determination method is provided in the embodiment, Figure 4 is a flowchart of another vehicle braking force determination method according to the embodiment of the present application, as Figure 4 shown, the flowchart includes the following steps:

[0086] Step S401, acquiring the pedal stroke signal collected by the pedal stroke sensor. For details, please refer to step S301 of the embodiment shown in Figure 3 herein, which will not be repeated.

[0087] Step S402, determining the target pedal stroke based on the pedal stroke signal.

[0088] Specifically, the above step S402 includes:

[0089] Step S4021, calculating the stroke error based on the pedal stroke signal.

[0090] In the embodiment, the stroke error is the error of the two pedal stroke signals, and its specific calculation method can be known by referring to the conventional operation in the art.

[0091] Step S4022, if the stroke error is greater than the preset threshold and lasts for a third preset time, reporting the vehicle fault and limiting the output of the vehicle braking force.

[0092] In the embodiment, the specific values of the preset threshold and the third preset time are not limited, and can be adaptively adjusted according to actual needs.

[0093] Step S4023, if the stroke error is not greater than the preset threshold, or the stroke error is greater than the preset threshold and does not last for the third preset time, calculating the stroke mean value based on the pedal stroke signal, and determining the stroke mean value as the target pedal stroke.

[0094] In the embodiment of the present application, the stroke error is calculated based on the pedal stroke signal, like the deviation of two signals of a sensor, and the signal validity is judged in combination with the double conditions that the error is greater than the threshold and lasts for a third preset time, so as to improve the signal reliability and effectively avoid the risk of misjudgment; and when the pedal stroke signal is reliable, the target pedal stroke is determined by calculating the stroke average, so that the target stroke is more stable and closer to the real braking intention of the driver.

[0095] It should be noted that the pedal stroke signal is prone to be abnormal due to sensor failure, line interference, etc., and in order to ensure the reliability of the pedal stroke signal and improve the accuracy of the braking force identification, it is necessary to ensure that the pedal stroke signal is real and effective. Therefore, before determining the target pedal stroke based on the pedal stroke signal, the vehicle braking force determination method of the embodiment further comprises:

[0096] Step a1, judging whether the pedal stroke signal is valid.

[0097] In the embodiment, whether the pedal stroke signal is valid can be judged based on the monitoring means of the sensor manual, the effective value identification of the underlying software and the application layer error checking, and the specific determination method is adaptively set based on actual needs.

[0098] Step a2, when the pedal stroke signal is valid, executing the step of determining the target pedal stroke based on the pedal stroke signal.

[0099] Step a3, when the pedal stroke signal is invalid, returning to execute the step of acquiring the pedal stroke signal collected by the pedal stroke sensor.

[0100] In a specific implementation, referring to the EMB system of Figure 2 , an effectiveness determination process of the pedal stroke signal is provided, which specifically comprises:

[0101] 1. Respectively detecting whether the controller X and the controller Y are currently in a normal working state.

[0102] 2. If the controller X is currently in a normal working state, acquiring the first signal and the second signal output by the pedal stroke sensor A, and respectively judging whether the first signal and the second signal are valid; when both the first signal and the second signal are valid, it is confirmed that the pedal stroke signal is valid; when the first signal or the second signal is invalid, it is confirmed that the pedal stroke signal is invalid.

[0103] 3. If the controller X is currently in an abnormal working state and the controller Y is currently in a normal working state, acquiring the third signal and the fourth signal output by the pedal stroke sensor B, and respectively judging whether the third signal and the fourth signal are valid; when both the third signal and the fourth signal are valid, it is confirmed that the pedal stroke signal is valid; when the third signal or the fourth signal is invalid, it is confirmed that the pedal stroke signal is invalid.

[0104] In the embodiment of the present application, by judging the signal validity before determining the target pedal stroke, invalid signals can be filtered in advance, and it is ensured that all signals entering the subsequent target pedal stroke determination step are reliable signals; the target stroke calculation error caused by invalid signals can be avoided from the source, and the deviation of brake force output from the real intention of the driver is prevented, which can significantly improve the accuracy of brake intention recognition and brake safety.

[0105] In step S403, all brake disc temperatures, brake pedal depths, activation states of the anti-lock braking system, and current braking forces fed back by the brake actuator in real time are acquired respectively, and a thermal decay analysis is performed on the brake actuator based on all the brake disc temperatures, brake pedal depths, activation states of the anti-lock braking system, and current braking forces, to obtain a thermal decay analysis result.

[0106] Specifically, the thermal decay analysis on the brake actuator based on all the brake disc temperatures, brake pedal depths, activation states of the anti-lock braking system, and current braking forces in step S403 to obtain the thermal decay analysis result includes:

[0107] In step b1, if any of the following conditions is met, it is determined that the thermal decay analysis result is thermal decay: any brake disc temperature exceeds a preset temperature threshold and lasts for a first preset time; or, the brake pedal depth exceeds a preset depth threshold and lasts for a second preset time; or, the anti-lock braking system is in an inactive state; or, the anti-lock braking system is in an active state, and the current braking force exceeds a preset braking force threshold.

[0108] It should be noted that the specific values of the preset temperature threshold, the first preset time, the preset depth threshold, the second preset time, and the preset braking force threshold are adaptively adjusted based on actual needs in the embodiment.

[0109] In the embodiment, the judgment based on the brake disc temperature can identify the conventional thermal decay caused by frictional heat, which is suitable for most braking scenarios; the judgment based on the pedal depth and the inactive ABS can identify the hidden thermal decay that occurs when the brake pedal is deeply pressed for a long time (e.g., long downhill) although the brake disc temperature does not reach the threshold; the judgment based on the current braking force when the ABS is activated can identify the special scenario where the braking force approaches the threshold due to thermal decay in the ABS working state; the combination of the three and the use of the “or” logic that determines thermal decay as soon as any condition is met avoid the missed judgment of a single identification method for a specific working condition, and further ensure that thermal decay in different braking scenarios can be effectively captured, greatly improving the comprehensiveness of thermal decay scenario identification.

[0110] In the embodiment of the present invention, by designing judgment conditions in three different dimensions, it can comprehensively cover various typical operating conditions in which the brake actuator may cause thermal degradation, significantly improve the effectiveness and safety of thermal degradation identification, provide an accurate basis for subsequent braking force adjustment, and thus ensure the stable operation of the brake system.

[0111] Step b2: If all brake disc temperatures do not exceed the preset temperature threshold, or a brake disc temperature exceeds the preset temperature threshold and does not last for a first preset time; and the brake pedal depth does not exceed the preset depth threshold, or the brake pedal depth exceeds the preset depth threshold and does not last for a second preset time, or the brake pedal depth exceeds the preset depth threshold and lasts for a second preset time, the anti-lock braking system is in an activated state; and when the anti-lock braking system is in an activated state, the current braking force does not exceed the preset braking force critical value, then it is determined that the thermal decay analysis result is that no thermal decay has occurred.

[0112] In this embodiment, "multiple conditions and logic" are used to strictly define scenarios in which thermal decay does not occur, and can accurately exclude scenarios in which "thermal decay is suspected but is actually normal braking" (such as instantaneous temperature fluctuations of the brake disc exceeding the limit but not persisting, normal braking when the pedal is deeply depressed but the ABS is activated, and the normal state in which the braking force is not close to the critical value when the ABS is working). This avoids misjudging normal braking as thermal decay and triggering unnecessary braking force compensation, and prevents sudden increases in braking force and sudden changes in pedal feel due to misjudgment, which affect driving safety and comfort.

[0113] In the embodiment of the present invention, by precisely defining non-thermal decay boundary conditions, refining constraints to avoid misjudgments, and forming a logical closed loop with thermal decay judgment, the stability and rationality of braking force output under normal working conditions are maintained while ensuring braking safety, taking into account both reliability and driving experience.

[0114] Step S404 : In response to the current brake pedal feel determined by the driver and based on the current brake pedal feel and the thermal fade analysis result, a target braking force corresponding to the target pedal stroke is determined.

[0115] It should be noted that due to individual differences in brake pedal feel, ignoring brake pedal feel when determining the target braking force can easily cause driver discomfort, affecting the driving experience and even driving safety. Therefore, this embodiment considers using the current brake pedal feel determined by the driver to calculate the target braking force corresponding to the target pedal travel.

[0116] In this embodiment, the thermal fade analysis results include thermal fade occurring and thermal fade not occurring. Specifically, when the thermal fade analysis result is that thermal fade not occurring, the target braking force corresponding to the target pedal stroke is determined based on the current brake pedal feel and the thermal fade analysis result in step S404, including:

[0117] Step c1: determining a first target curve based on the current brake pedal feel.

[0118] In this embodiment, the first target curve is a mapping curve of the relationship between the pedal stroke and the braking force of the entire vehicle, which represents a normal braking curve.

[0119] Step c2: searching for the corresponding target braking force from a first target curve based on the target pedal stroke; wherein the first target curve is a relationship mapping curve between different brake pedal strokes and vehicle braking force.

[0120] In an embodiment of the present invention, when the thermal degradation analysis result shows that no thermal degradation has occurred, by selecting the corresponding first target curve based on the current brake pedal feel determined by the driver to output the corresponding braking force, the braking response can be made more in line with the driver's expectations, significantly improving driving comfort and control experience.

[0121] It should be noted that this embodiment takes into account the problem that thermal fade can cause a decrease in the actual braking force of the brake actuator. A second target curve is specifically designed to compensate for the loss of braking force caused by thermal fade. Specifically, when the thermal fade analysis result indicates that thermal fade has occurred, the target braking force corresponding to the target pedal travel is determined in step S404 based on the current brake pedal feel and the thermal fade analysis result, including:

[0122] In step d1 , a first target curve and a second target curve are determined based on the current brake pedal feel.

[0123] In this embodiment, the second target curve is a relationship mapping curve of the compensation braking force.

[0124] In step d2 , a first braking force is searched from a first target curve based on the target pedal travel, and a second braking force is searched from a second target curve.

[0125] Step d3, summing the first braking force and the second braking force to obtain a target braking force corresponding to the target pedal stroke; wherein the second target curve is a relationship mapping curve between different brake pedal strokes and the compensation braking force.

[0126] In this embodiment, during thermal decay, the superposition of the normal curve braking force and the compensation curve braking force corresponding to the same pedal feel can not only supplement the braking force to offset the decay effect, but also maintain the consistency of the braking force output with the driver's operating habits. For example, the braking force growth trend corresponding to the change in pedal travel still conforms to the selected pedal feel, avoiding sudden changes in pedal feel due to the compensation mechanism, reducing the driver's operating adaptation cost, and improving the consistency of the driving experience.

[0127] It should be noted that the first target curve and the second target curve in the embodiment are both preset relationship mapping curves, the design, storage and calling of which are based on the existing software architecture of the brake system (such as the lookup table logic in the controller), without the need to add hardware or complex algorithms, and the compensation value can be superimposed only by determining the state (whether heat decay) to achieve this design, which can make full use of the existing system resources, greatly reduce the development cost and technical difficulty, and facilitate the engineering landing and batch application.

[0128] In the embodiment, the determination process of the first target curve and the second target curve includes:

[0129] In step e1, a basic brake force stroke curve is calculated based on the relationship among the vehicle brake force, the vehicle mass and the vehicle acceleration, and the basic brake force stroke curve is calibrated and corrected according to the actuator parameters to obtain the first target curve.

[0130] In the embodiment, the first target curve is calculated based on the relationship among the vehicle brake force, the vehicle mass and the vehicle acceleration to obtain the basic brake force stroke curve, which ensures that the curve meets the physical requirements of vehicle braking from a theoretical level; at the same time, the theoretical curve can be matched with the hardware performance of the actual brake actuator through curve calibration and correction, so as to eliminate the deviation between the theoretical calculation and the actual hardware output (such as the difference between the actual clamping force of the actuator and the theoretical value), and ensure that the first target curve can truly reflect the braking capacity of the actuator, so that the brake force output is accurately controllable during normal braking.

[0131] In step e2, a heat decay brake compensation curve is determined based on preset configuration requirements, and the heat decay brake compensation curve is calibrated and corrected according to the actuator parameters to obtain the second target curve; wherein the preset configuration requirements include that when the brake pedal stroke reaches the maximum value, the compensation brake force output is the maximum clamping force of the brake actuator, and the brake force corresponding to each brake pedal stroke is compensated at a preset proportion.

[0132] In the embodiment, the second target curve is determined based on the preset configuration requirements, which clearly defines the core compensation target during heat decay: not only to fully release the actuator capacity (maximum clamping force) in extreme conditions (pedal to the floor), but also to achieve uniform and reasonable brake force compensation through proportional compensation at different strokes to avoid insufficient or excessive compensation; similarly, the compensation curve is adapted to the actual performance limit of the actuator (such as the actual value of the maximum clamping force and the compensation response speed at different strokes) through actuator parameter calibration and correction, so as to ensure that the compensation brake force will not exceed the hardware capacity of the actuator (such as avoiding requesting the maximum output of the actuator clamping force), and will not be delayed due to the hardware characteristics (such as actuator hysteresis), so as to ensure that the compensation effect during heat decay is real and effective.

[0133] The curve determination process in the embodiment of the application, by combining theory with practice, unifying logical design, reducing complexity and improving expandability, ensures that the first target curve and the second target curve can not only accurately match the braking demand and hardware capability, but also efficiently land application, thereby providing a reliable curve basis for accurate output of braking force under various actual working conditions.

[0134] In a specific embodiment, when there is no thermal recession, a normal braking type lookup table curve (i.e., the first target curve, which is a two-dimensional curve) is used, at this time, different curves are used according to the pedal feeling selected by the driver, and the corresponding braking force is obtained according to the pedal stroke lookup table. It should be noted that the lookup table curve can be calculated by F=M*a, where F is the vehicle braking force, M is the vehicle mass, and a is the vehicle acceleration. Specifically, the relationship between the vehicle pedal depth and the vehicle acceleration is obtained, and the preliminary version of the lookup table curve can be calculated by the formula, and the curve is corrected according to the real vehicle data. It should be noted that when the curve is initially less than 80% of the pedal depth, the braking force request should be relatively gentle, and the requested braking force can be increased faster in the last 20%. This design can reduce the impact of the driver accidentally stepping too deep due to the lack of pedal feel. At the same time, the lookup table curve should also hide a part of the braking capacity, and the capacity will be fully released after identifying the thermal recession, which can also reduce the impact of the driver accidentally stepping too deep due to the lack of pedal feel.

[0135] In a specific embodiment, the capability of a commonly used actuator is used for illustration, assuming that the maximum single-wheel clamping force of the front axle EMB is 65000N, and the maximum single-wheel clamping force of the rear axle EMB is 35000N; a CF value (representing the ability to convert the wheel end clamping force into wheel end braking torque) is proposed according to the caliper characteristics, and the CF value is generally around 0.12; when thermal recession occurs, the CF value will decrease; assuming that the wheel end radius R=0.383m, according to the following formula:

[0136] F n × CF = F x × R (1)

[0137] wherein F n is the single-wheel clamping force, and F x is the single-wheel braking force.

[0138] Specifically, according to the above conditions, the maximum single-wheel braking force of the front axle is calculated to be 20366N, and the maximum single-wheel braking force of the rear axle is calculated to be 10966N; then the vehicle braking force is calculated to be 20366*2+10966*2=62664N; according to F=M*a, wherein M is the vehicle mass and is assumed to be 2800Kg, the maximum deceleration of the vehicle can reach 22.38m / s 2In actual applications, since the vehicle often doesn't require such a large deceleration, some braking capacity can be hidden. That is, when thermal decay doesn't occur and the CF value decreases, full braking capacity is not required even when the pedal is fully depressed. In this case, a curve is determined based on the relationship between the vehicle's deceleration and pedal travel. Using the commonly used relationship between vehicle pedal travel and deceleration, and the aforementioned calculation method, the following relationship table between brake pedal travel and vehicle braking force can be obtained. It should be noted that the data in Table 1 can support a single curve.

[0139] Table 1

[0140] Brake pedal stroke (m) Vehicle braking force (N) 0％ 0 14.3％ 2160 25％ 6750 35.7％ 10800 55.4％ 17500 71.4％ 24300 83.9％ 29700 89.3％ 35100 92.9％ 40500 96.4％ 48600 100％ 55000

[0141] It should be noted that a curve can be drawn from the data in Table 1, and this curve can be used as a lookup curve when no thermal decay occurs.

[0142] In this embodiment, maximum braking force is required when thermal fade occurs to prevent insufficient braking force. Specifically, when using a thermal fade lookup compensation curve, the driver's selected pedal feel must still be used, and the corresponding braking force is retrieved based on pedal travel. This curve serves as a compensation for the non-thermal fade curve. That is, after thermal fade is identified, a supplementary braking force is retrieved from the table and then superimposed on the braking force from the non-thermal fade curve to form the final requested braking force. It should be noted that the compensation curve only requires maximum braking force to be released when the pedal is fully depressed. That is, at 100%, the output braking force is 62,664 N. The percentage required for compensation is approximately (62,664 - 55,000) / 55,000, or approximately 13.9%. The braking force corresponding to each travel distance can then be simply compensated according to this ratio. It should be noted that both of these curves require calibration based on the different EMB actuator parameters to achieve optimal results.

[0143] In one embodiment, see Figure 2 The EMB system provides a solution for determining vehicle braking force. Figure 5 It is a flow chart of the vehicle braking force determination scheme. Figure 5 As we know, the process includes:

[0144] 1. Obtain the driver's brake pedal feel selection, pedal travel signals A1, A2, B1, B2, and brake disc temperature.

[0145] In this embodiment, controller X receives two pedal travel signals A1 and A2 from pedal travel sensor A, and also receives two pedal travel signals B1 and B2 from pedal travel sensor B of controller Y. Note that the driver's brake pedal feel selection is also called selected pedal feel.

[0146] 2. Obtain pedal travel L.

[0147] In the embodiment, firstly, the actual states of the controller X and the controller Y need to be judged. The method provided in the chip manual selected by the controller can be developed to monitor the failure and abnormality of the chip. Meanwhile, some current and voltage values can be monitored and judged. Specifically, if the controller X and the controller Y are in the normal working state, the determination process of the pedal stroke L includes:

[0148] 1: Firstly, the valid bits of A1 and A2 are judged. If any one of the signals is invalid, B1 and B2 are used.

[0149] 1.1: If any one of B1 and B2 is invalid at this time, it is considered that the two pedal stroke sensors A and B cannot obtain the correct braking intention of the driver at this time. At this time, the vehicle reports a fault and performs corresponding function degradation. At this time, the brake pedal will not produce braking force.

[0150] 1.2: If B1 and B2 are valid, the error between B1 and B2 is judged.

[0151] 1.2.1: When the error is greater than the threshold value and lasts for a certain time, it is considered that the stroke of B1 and B2 is unreliable. At this time, it is similar to 1.1 described above. The vehicle reports a fault and performs corresponding function degradation. At this time, the brake pedal will not produce braking force.

[0152] 1.2.2: If the error is less than the threshold value, or greater than the threshold value but the duration is not enough, the strokes of B1 and B2 are averaged to determine the pedal stroke L required by the driver.

[0153] 2: If the valid bits of A1 and A2 are valid, the error between A1 and A2 is judged.

[0154] 2.1: If the error between A1 and A2 is greater than the threshold value and lasts for a certain time, it is considered that the stroke of A1 and A2 is unreliable, and B1 and B2 are used.

[0155] 2.1.1: If any one of B1 and B2 is invalid at this time, it is considered that the two pedal stroke sensors A and B cannot obtain the correct braking intention of the driver at this time. At this time, the vehicle reports a fault and performs corresponding function degradation. At this time, the brake pedal will not produce braking force.

[0156] 2.1.2: If B1 and B2 are valid, the error between B1 and B2 is judged.

[0157] 2.1.2.1: When the error between B1 and B2 is greater than the threshold value and lasts for a certain time, it is considered that the stroke of B1 and B2 is unreliable, at this time, it is similar to the description of 2.1.1, the vehicle reports a fault and performs corresponding function degradation, at this time, stepping on the brake pedal will not generate braking force.

[0158] 2.1.2.2: If the error between B1 and B2 is less than the threshold value, or greater than the threshold value but the duration is not enough, then the strokes of B1 and B2 are averaged to determine the pedal stroke L required by the driver.

[0159] 2.2: If the error between A1 and A2 is less than the threshold value or the duration is not enough, it is considered that A1 and A2 truly reflect the braking intention of the driver, at this time, the average value of A1 and A2 is taken as the pedal stroke L required by the driver.

[0160] In this embodiment, if only controller X is in normal working mode, it is considered that B1 and B2 transmitted by controller Y are invalid, at this time, A1 and A2 are judged.

[0161] 1: If one of A1 and A2 is invalid, it is considered that the pedal stroke sensor A cannot correctly obtain the braking intention of the driver, at this time, the vehicle reports a fault and performs corresponding function degradation, at this time, stepping on the brake pedal will not generate braking force.

[0162] 2: If A1 and A2 are both valid, the error between A1 and A2 is judged.

[0163] 2.1: If the error between A1 and A2 is greater than the threshold value and lasts for a certain time, it is considered that the stroke of A1 and A2 is unreliable, at this time, the vehicle reports a fault and performs corresponding function degradation, at this time, stepping on the brake pedal will not generate braking force.

[0164] 2.2: If the error between A1 and A2 is less than the threshold value or the duration is not enough, it is considered that A1 and A2 truly reflect the braking intention of the driver, at this time, the average value of A1 and A2 is taken as the pedal stroke L required by the driver.

[0165] In this embodiment, if only controller Y is in normal working mode, the backup controller working process is started, at this time, A1 and A2 of the pedal stroke sensor A transmitted by controller X are considered unreliable, only B1 and B2 are used to judge the driver's intention, at this time, B1 and B2 are judged.

[0166] 1: If one of B1 and B2 is invalid, it is considered that the pedal stroke sensor B cannot correctly obtain the braking intention of the driver, at this time, the vehicle reports a fault and performs corresponding function degradation, at this time, stepping on the brake pedal will not generate braking force.

[0167] 2: If B1 and B2 are both valid, the error between B1 and B2 is judged.

[0168] 2.1: If the error between B1 and B2 is greater than a threshold value and lasts for a certain time, it is considered that the stroke of B1 and B2 is unreliable, at this time the vehicle is reported to be faulty and the corresponding function is degraded, at this time stepping on the brake pedal will not produce braking force.

[0169] 2.2: If the error between B1 and B2 is less than a threshold value or the duration is not enough, it is considered that B1 and B2 truly reflect the driver's braking intention, at this time the average value of B1 and B2 is taken as the pedal stroke L required by the driver.

[0170] 3. Determine whether heat recession.

[0171] In this embodiment, after obtaining the pedal stroke L required by the driver according to the above operation, it is also necessary to determine whether the brake actuator produces heat recession; if heat recession occurs, the maximum clamping force needs to be released in order to obtain greater braking force and avoid the situation of insufficient braking force. Specifically, in this embodiment, whether heat recession occurs is determined by the following three ways:

[0172] (1) According to the model brake disc temperature feedback by the brake actuator, if the temperature of one of the four brake discs exceeds a threshold value and lasts for a certain time, it is considered that heat recession occurs.

[0173] (2) If the brake pedal is depressed to a certain depth and lasts for a period of time, the depth can be calibrated and can be determined through multiple tests. At this time, the ABS is not activated (which can be determined by the ABS function activation flag bit transmitted by the ABS function software), that is, the actuator works with a larger clamping force, it is considered that heat recession occurs.

[0174] (3) When the ABS is activated, the braking force feedback by the actuator has approached the calibrated non-heat recession maximum braking force, it is considered that heat recession occurs. It should be noted that because the non-heat recession maximum braking force will be greater than the braking force required for actual control when the ABS is activated, but after heat recession in order to provide better braking effect, the braking force will be continuously requested to increase; when the difference between the two is small, it is considered that heat recession occurs.

[0175] It should be noted that way (1) is a commonly used heat recession identification scheme, and any one of the three ways is considered to trigger heat recession; among them, way (1) is used for identification first, and ways (2) and (3) are used as supplementary identification ways.

[0176] 4. When heat recession occurs, the selected table curve is determined according to the heat recession and the selected pedal feeling, and the braking force is obtained according to the pedal stroke L.

[0177] 5. When no thermal recession occurs, the selected table curve is determined according to the selected pedal feeling and the non-thermal recession, and the braking force is obtained by table lookup according to the pedal stroke L.

[0178] In the embodiment, after the pedal stroke L and the case of whether thermal recession occurs are obtained through the above steps, the braking force corresponding to the stroke is determined according to the pedal feeling selected by the driver. Specifically, when no thermal recession occurs, the normal braking type table curve is used, at this time, different curves are used according to the selected pedal feeling, and the corresponding braking force is obtained according to the pedal stroke L. Conversely, when thermal recession occurs, the corresponding braking force can also be obtained in this way.

[0179] In summary, the embodiment is targeted from multiple aspects to solve some problems existing in the current EMB products, so that the driver's braking intention can be correctly identified on the EMB product, and the corresponding braking force is obtained. Specifically, multi-dimensional parameters are used for thermal recession analysis and adaptation to different driver operation habits, which not only realizes comprehensive and accurate identification of thermal recession, but also guarantees accurate identification of braking force, greatly improving user experience.

[0180] In the embodiment, a vehicle braking force determination device is also provided, which is used to implement the above embodiments and preferred embodiments, and will not be described again. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware is also possible and contemplated.

[0181] The present application provides a vehicle braking force determination device, as shown in the accompanying drawings, the device comprises: Figure 6

[0182] The signal acquisition module 601 is configured to acquire a pedal stroke signal collected by a pedal stroke sensor.

[0183] The stroke determination module 602 is configured to determine a target pedal stroke based on the pedal stroke signal.

[0184] The thermal recession analysis module 603 is configured to respectively acquire all brake disc temperatures, brake pedal depths, anti-lock braking system activation states, and current braking forces fed back by a braking execution mechanism in real time, and perform thermal recession analysis on the braking execution mechanism based on all brake disc temperatures, brake pedal depths, anti-lock braking system activation states, and current braking forces, to obtain a thermal recession analysis result.

[0185] The braking force determination module 604 is configured to determine a target braking force corresponding to the target pedal stroke based on a current braking pedal feeling determined by the driver and the current braking pedal feeling and the thermal recession analysis result. ​

[0186] In some optional embodiments, the stroke determination module 602 comprises a first determination submodule, a second determination submodule, and a third determination submodule; the first determination submodule is configured to calculate a stroke error based on the pedal stroke signal; the second determination submodule is configured to, if the stroke error is greater than a preset threshold value and lasts for a third preset time, report a vehicle fault and limit the output of the vehicle braking force; and the third determination submodule is configured to, if the stroke error is not greater than the preset threshold value, or the stroke error is greater than the preset threshold value and does not last for the third preset time, calculate a stroke mean value based on the pedal stroke signal, and determine the stroke mean value as the target pedal stroke.

[0187] In some optional embodiments, the device further comprises a signal determination module configured to determine whether the pedal stroke signal is valid; when the pedal stroke signal is valid, the step of determining the target pedal stroke based on the pedal stroke signal is performed; and when the pedal stroke signal is invalid, the step of obtaining the pedal stroke signal collected by the pedal stroke sensor is re-executed.

[0188] In some optional embodiments, the heat fade analysis module 603 comprises a first analysis submodule, a second analysis submodule, and a third analysis submodule; the first analysis submodule is configured to respectively obtain all brake disc temperatures, brake pedal depths, activation states of an anti-lock braking system, and current braking forces fed back by a brake actuator in real time; the second analysis submodule is configured to, if any of the brake disc temperatures exceeds a preset temperature threshold value and lasts for a first preset time, or the brake pedal depth exceeds a preset depth threshold value and lasts for a second preset time, the anti-lock braking system is in an inactive state, or the anti-lock braking system is in an active state, and the current braking force exceeds a preset braking force threshold value, determine that the heat fade analysis result is that heat fade occurs; and the third analysis submodule is configured to, if all brake disc temperatures do not exceed the preset temperature threshold value, or any brake disc temperature exceeds the preset temperature threshold value and does not last for the first preset time, and the brake pedal depth does not exceed the preset depth threshold value, or the brake pedal depth exceeds the preset depth threshold value and does not last for the second preset time, or the brake pedal depth exceeds the preset depth threshold value and lasts for the second preset time, the anti-lock braking system is in the active state, and the current braking force does not exceed the preset braking force threshold value, determine that the heat fade analysis result is that heat fade does not occur.

[0189] In some optional embodiments, the brake force determination module 604 comprises a first identification submodule, a second identification submodule and a third identification submodule; the first identification submodule is configured to determine a first target curve based on the current brake pedal feeling determined by the driver; the second identification submodule is configured to determine a first target curve based on the current brake pedal feeling when the heat fade analysis result is no heat fade; and the corresponding target brake force is found from the first target curve based on the target pedal stroke; the first target curve is a mapping curve of different brake pedal strokes and vehicle brake forces; the third identification submodule is configured to determine a first target curve and a second target curve based on the current brake pedal feeling when the heat fade analysis result is heat fade; the first brake force is found from the first target curve and the second brake force is found from the second target curve based on the target pedal stroke; and the target brake force corresponding to the target pedal stroke is obtained by summing the first brake force and the first brake force; the second target curve is a mapping curve of different brake pedal strokes and compensation brake forces.

[0190] In some optional embodiments, the brake force determination module 604 further comprises a fourth identification submodule configured to obtain a basic brake force stroke curve based on the relationship among the vehicle brake force, the vehicle mass and the vehicle acceleration, and to calibrate and correct the basic brake force stroke curve according to the actuator parameters to obtain the first target curve; and to determine a heat fade brake compensation curve based on a preset configuration requirement, and to calibrate and correct the heat fade brake compensation curve according to the actuator parameters to obtain the second target curve; the preset configuration requirement comprises that a compensation brake force is output to release the maximum clamping force of the brake actuator when the brake pedal stroke reaches the maximum value, and the brake force corresponding to each brake pedal stroke is compensated at a preset proportion.

[0191] Further function descriptions of the above modules are the same as those of the corresponding embodiments described above, and will not be described here again.

[0192] The vehicle brake force determination device in the embodiment is presented in the form of a functional unit, and the unit herein refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and a memory executing one or more software or fixed programs, and / or other devices that can provide the above functions.

[0193] The vehicle brake force determination device in the embodiment can perform comprehensive and accurate identification of heat fade by performing heat fade analysis on multi-dimensional parameters and adapting to different driver operation habits, i.e., determining the target brake force corresponding to the target pedal stroke by using the current brake pedal feeling and the heat fade analysis result, thereby ensuring accurate determination of the brake force, which not only helps to truly reflect the brake demand of the driver, but also greatly improves the user experience and effectively avoids the driving safety risk of the vehicle.

[0194] An embodiment of the present invention further provides a vehicle comprising a controller. The controller in this embodiment is a controller for an EMB system, which is used to perform operations such as powering on / off, and waking up from sleep mode for its subordinate sub-controllers and network nodes. At the same time, each of its power supply interfaces is capable of collecting real-time output current. Other controllers with the above-mentioned functions are applicable. It should be noted that the controllers in this embodiment are two controllers with the same structure and function, and the following detailed description will be given using either controller as an example.

[0195] Figure 7 is a schematic diagram of the structure of the controller provided in an optional embodiment of the present invention, such as Figure 7 As shown, the controller includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. The various components utilize different buses to communicate with each other and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the controller, including instructions stored in or on the memory to display graphical information of a GUI on an external input / output system (such as a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple controllers can be connected, and each controller provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 7 A processor 10 is taken as an example.

[0196] The processor 10 may be a central processing unit, a network processor, or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0197] The memory 20 stores instructions that can be executed by at least one processor 10, so as to enable at least one processor 10 to execute the method shown in the above embodiment.

[0198] The memory 20 can include a program storage area and a data storage area. The program storage area can store an operating system and application programs required by at least one function. The data storage area can store data created according to the use of the controller, etc. In addition, the memory 20 can include a high-speed random access memory and can also include a non-transitory memory such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state memory device. In some alternative embodiments, the memory 20 can optionally include a memory disposed remotely with respect to the processor 10, which can be connected to the controller through a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0199] The memory 20 can include a volatile memory such as a random access memory, and can also include a non-volatile memory such as a flash memory, a hard disk, or a solid state disk. The memory 20 can also include a combination of the above-mentioned types of memories.

[0200] The controller further includes a communication interface 30 for the host chip to communicate with other devices or communication networks.

[0201] The embodiments of the present application also provide a computer readable storage medium. The above-mentioned method according to the embodiments of the present application can be implemented in hardware, firmware, or recorded in a storage medium, or implemented as computer code stored in a remote storage medium or a non-transitory machine readable storage medium and stored in a local storage medium to be downloaded through a network, so that the method described herein can be processed by such software on a storage medium using a general-purpose computer, a special-purpose processor, or programmable or special-purpose hardware. The storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid state disk, etc. Further, the storage medium can also include a combination of the above-mentioned types of memories. It can be understood that the computer, the processor, the microprocessor host chip, or the programmable hardware includes a storage component that can store or receive software or computer code, which, when accessed and executed by the computer, the processor, or the hardware, implements the method shown in the above-mentioned embodiments.

[0202] Although the embodiments of the present application have been described in conjunction with the accompanying drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A method for determining vehicle braking force, characterized in that: The method comprises: Acquiring a pedal stroke signal collected by a pedal stroke sensor; determining a target pedal stroke based on the pedal stroke signal; acquiring all brake disc temperatures, brake pedal depths, activation states of an anti-lock braking system, and current braking forces fed back in real time by a brake actuator, respectively, and performing a thermal fade analysis on the brake actuator based on all brake disc temperatures, the brake pedal depths, activation states of the anti-lock braking system, and the current braking forces to obtain a thermal fade analysis result; In response to a current brake pedal feel determined by a driver and based on the current brake pedal feel and the thermal fade analysis result, a target braking force corresponding to the target pedal stroke is determined.

2. The vehicle braking force determination method according to claim 1, characterized in that: The performing of thermal fade analysis on the brake actuator based on the temperatures of all brake discs, the brake pedal depth, the activation state of the anti-lock braking system, and the current braking force to obtain a thermal fade analysis result includes: If the temperature of any brake disc exceeds a preset temperature threshold and lasts for a first preset time; Alternatively, when the brake pedal depth exceeds a preset depth threshold and lasts for a second preset time, the anti-lock braking system is in an inactive state; Alternatively, when the anti-lock braking system is in an activated state, if the current braking force exceeds a preset braking force threshold value, it is determined that the thermal decay analysis result is that thermal decay occurs.

3. The vehicle braking force determination method according to claim 2, characterized in that: The method further comprises: If the temperatures of all brake discs do not exceed the preset temperature threshold, or if the temperature of one brake disc exceeds the preset temperature threshold and does not last for a first preset time; Furthermore, when the brake pedal depth does not exceed a preset depth threshold, or the brake pedal depth exceeds the preset depth threshold and does not last for a second preset time, or the brake pedal depth exceeds the preset depth threshold and lasts for a second preset time, the anti-lock braking system is in an activated state; Furthermore, when the anti-lock braking system is in an activated state, the current braking force does not exceed a preset braking force threshold value, and the thermal decay analysis result is determined to be no thermal decay.

4. The vehicle braking force determination method according to claim 3, characterized in that: When the thermal fade analysis result indicates that no thermal fade has occurred, determining the target braking force corresponding to the target pedal stroke based on the current brake pedal feel and the thermal fade analysis result includes: determining a first target curve based on the current brake pedal feel; Based on the target pedal stroke, a corresponding target braking force is searched from the first target curve; wherein the first target curve is a mapping curve of the relationship between different brake pedal strokes and the braking force of the entire vehicle.

5. The vehicle braking force determination method according to claim 4, characterized in that: When the thermal fade analysis result indicates that thermal fade has occurred, determining the target braking force corresponding to the target pedal stroke based on the current brake pedal feel and the thermal fade analysis result includes: determining a first target curve and a second target curve based on the current brake pedal feel; searching for a first braking force from the first target curve and a second braking force from the second target curve based on the target pedal travel; The first braking force and the second braking force are summed to obtain a target braking force corresponding to the target pedal stroke; wherein the second target curve is a relationship mapping curve between different brake pedal strokes and compensation braking forces.

6. The vehicle braking force determination method according to claim 5, characterized in that: The process of determining the first target curve and the second target curve includes: A basic braking force stroke curve is calculated based on the relationship between the whole vehicle braking force, the whole vehicle mass and the whole vehicle acceleration, and the basic braking force stroke curve is calibrated and corrected according to the actuator parameters to obtain the first target curve; A thermal fade brake compensation curve is determined based on preset configuration requirements, and the thermal fade brake compensation curve is calibrated and corrected according to actuator parameters to obtain the second target curve; wherein the preset configuration requirements include outputting a compensating braking force that causes the brake actuator to release the maximum clamping force when the brake pedal stroke reaches a maximum value, and the braking force corresponding to each brake pedal stroke is compensated according to a preset ratio.

7. The vehicle braking force determination method according to any one of claims 1 to 6, characterized in that: The determining the target pedal stroke based on the pedal stroke signal includes: calculating a travel error based on the pedal travel signal; If the travel error is greater than a preset threshold and lasts for a third preset time, a vehicle fault is reported and the output of the vehicle braking force is limited; If the stroke error is not greater than the preset threshold, or the stroke error is greater than the preset threshold and does not last for a third preset time, a stroke average is calculated based on the pedal stroke signal, and the stroke average is determined as the target pedal stroke.

8. The vehicle braking force determination method according to claim 7, characterized in that: Before determining the target pedal stroke based on the pedal stroke signal, the method further includes: determining whether the pedal stroke signal is valid; When the pedal stroke signal is valid, performing the step of determining the target pedal stroke based on the pedal stroke signal; When the pedal stroke signal is invalid, the process returns to the step of obtaining the pedal stroke signal collected by the pedal stroke sensor.

9. A vehicle braking force determination device, characterized in that: The device comprises: A signal acquisition module is used to acquire a pedal stroke signal collected by a pedal stroke sensor; a stroke determination module, configured to determine a target pedal stroke based on the pedal stroke signal; a thermal fade analysis module, configured to respectively obtain all brake disc temperatures, brake pedal depth, activation state of the anti-lock brake system, and current braking force fed back in real time by a brake actuator, and perform a thermal fade analysis on the brake actuator based on all brake disc temperatures, the brake pedal depth, activation state of the anti-lock brake system, and the current braking force, to obtain a thermal fade analysis result; The braking force determination module is configured to determine a target braking force corresponding to the target pedal stroke in response to a current brake pedal feel determined by a driver and based on the current brake pedal feel and the thermal fade analysis result.

10. A vehicle, characterized in that: The vehicle includes a controller, which includes: a memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the vehicle braking force determination method according to any one of claims 1 to 8 by executing the computer instructions.

11. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the vehicle braking force determination method according to any one of claims 1 to 8.

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