Brake-by-wire system anti-lock braking control methods, devices, equipment, and vehicles

Abstract

This invention discloses an anti-lock braking control method, device, equipment, and vehicle for a brake-by-wire system. It belongs to the field of vehicle technology. The method includes: acquiring a first set of wheel speeds, which includes the wheel speeds of all wheels; determining a reference vehicle speed based on the first set of wheel speeds; calculating a slip ratio based on the reference vehicle speed; and adjusting braking pressure based on the slip ratio and vehicle status, wherein the vehicle status includes a normal braking state, a slip state, a slip recovery process state, a slip recovery completed state, and a slip recovery timeout state. This invention has advantages such as high control precision, fast response speed, and strong robustness, which can significantly improve vehicle braking safety and braking efficiency, providing a guarantee for the safe and reliable operation of the brake-by-wire system.

Description

Technical Field

[0001] This invention belongs to the field of vehicle technology, specifically relating to anti-lock braking control methods, devices, equipment, and vehicles for brake-by-wire systems. Background Technology

[0002] With the rapid development of electric vehicles and advanced autonomous driving technologies, traditional hydraulic braking systems have been gradually replaced by brake-by-wire systems. Brake-by-wire systems are mainly divided into two technical routes: electro-hydraulic braking and electro-mechanical braking. Their core advantages lie in their fast response speed, high braking energy recovery efficiency, and seamless integration with intelligent driving systems.

[0003] However, brake-by-wire systems face significant challenges in single-path control mode. Traditional ABS (Anti-lock Braking System) typically uses the average or maximum wheel speed of all four wheels as the reference speed. However, in brake-by-wire systems, because only one braking pressure can be controlled, this reference speed calculation method is susceptible to single-wheel failure or lock-up, leading to system misjudgments. For example, during high-speed braking, if a wheel's speed is significantly lower than other wheels due to sensor failure or lock-up, the reference speed calculation of traditional ABS will introduce a large deviation, thus affecting the accuracy of slip ratio control.

[0004] In terms of signal processing, existing ABS systems mostly use Kalman filtering or first-order low-pass filtering. Although these methods can effectively suppress noise, they have the following limitations: Kalman filtering is sensitive to noise parameters and requires preset fixed values, while first-order low-pass filtering has a lagging dynamic response, which cannot meet the high real-time requirements of brake-by-wire systems. In addition, the state switching logic of traditional ABS usually relies only on a single slip rate threshold, lacking a comprehensive judgment of the slip rate change rate (differential) and process time, leading to control lag or misjudgment, especially under complex road conditions. Summary of the Invention

[0005] One object of the present invention is to provide a method, apparatus, equipment, and vehicle for anti-lock braking control of a brake-by-wire system, which can solve the above-mentioned technical problems in the prior art.

[0006] According to a first aspect of the present invention, an anti-lock braking control method for a brake-by-wire system is provided, comprising:

[0007] Obtain the first set of wheel speeds, which includes the wheel speeds of all wheels;

[0008] The reference vehicle speed is determined based on the first set of wheel speeds;

[0009] Calculate the slip ratio based on the reference vehicle speed;

[0010] Adjust the braking pressure according to the slip ratio and vehicle status, wherein the vehicle status includes normal braking status, slip status, slip recovery process status, slip recovery completed status, and slip recovery timeout status.

[0011] Optionally, determining the reference vehicle speed based on the first set of wheel speeds includes:

[0012] A second set of wheel speeds is determined based on the first set of wheel speeds, and the second set of wheel speeds includes all wheel speeds in the first set of wheel speeds except for the minimum wheel speed.

[0013] Obtain the vertical load of all wheels corresponding to the second set of wheel speeds;

[0014] The weight of each wheel is determined based on the vertical load.

[0015] The reference vehicle speed is calculated based on the weight of each wheel and the second set of wheel speeds.

[0016] Optionally, before calculating the slip ratio based on the reference vehicle speed, the method further includes:

[0017] The reference vehicle speed is subjected to a second-order FIR low-pass filter;

[0018] Slope limiting is applied to the filtered reference vehicle speed.

[0019] Optionally, the conditions for switching the vehicle state include:

[0020] When the vehicle is in a normal braking state, if the slip ratio is greater than a first slip ratio threshold, the slip ratio difference is greater than a first slip ratio difference threshold, and the first duration is greater than a first time threshold, the vehicle state switches from the normal braking state to the slip state, wherein the first duration is the duration during which the slip ratio is greater than the first slip ratio threshold and the slip ratio difference is greater than the first slip ratio difference threshold;

[0021] When the vehicle is in the slip state, if the slip ratio is less than the second slip ratio threshold, the slip ratio difference is less than the second slip ratio difference threshold, and the second duration is greater than the second time threshold, the vehicle state switches from the slip state to the slip recovery process state. The second duration is the duration during which the slip ratio is less than the second slip ratio threshold and the slip ratio difference is less than the second slip ratio difference threshold.

[0022] When the vehicle is in the slip state, if the slip rate is greater than the second slip rate threshold and the third duration is greater than the third time threshold, the vehicle state switches from the slip state to the slip recovery timeout state, and the third duration is the duration during which the slip rate is greater than the second slip rate threshold;

[0023] When the vehicle is in the slip recovery process state, if the slip ratio is less than the second slip ratio threshold and the fourth duration is greater than the second time threshold, the vehicle state switches from the slip recovery process state to the slip recovery completed state, and the fourth duration is the duration during which the slip ratio is less than the second slip ratio threshold;

[0024] If the vehicle is in the state of complete slip recovery and the duration exceeds a fourth time threshold, the vehicle state switches from the state of complete slip recovery to the state of normal braking.

[0025] Optionally, the first slip ratio threshold is 25%, the first slip ratio difference threshold is +0.1g / s, the first time threshold is 500ms, the second slip ratio threshold is 15%, the second slip ratio difference threshold is -0.1g / s, the second time threshold is 200ms, the third time threshold is 2000ms, and the fourth time threshold is 1500ms.

[0026] Optionally, adjusting the braking pressure based on the slip ratio and vehicle condition includes:

[0027] When the vehicle is in the slip state, decompression control is implemented;

[0028] When the vehicle is in the slip recovery process state, pressure holding control is implemented;

[0029] When the vehicle is in the state of complete slip recovery, boost control is implemented;

[0030] When the vehicle is in the slip recovery timeout state, control is turned off.

[0031] Optionally, adjusting the braking pressure according to the slip ratio and vehicle condition further includes:

[0032] Under various vehicle conditions, the PD control algorithm is used to adjust the braking pressure:

[0033] ;

[0034] in, For brake pressure adjustment amount, This is the proportionality coefficient. The differential coefficients are... For slip ratio, For time, This represents the slip ratio difference.

[0035] According to a second aspect of the present invention, an apparatus for an anti-lock braking control method for a brake-by-wire system according to a first aspect of the present invention is provided, comprising:

[0036] The wheel speed acquisition module is used to acquire a first wheel speed set, which includes the wheel speeds of all wheels;

[0037] The vehicle speed calculation module is used to determine a reference vehicle speed based on the first set of wheel speeds.

[0038] The slip ratio calculation module is used to calculate the slip ratio based on the reference vehicle speed;

[0039] The pressure calculation module is used to adjust the braking pressure according to the slip ratio and vehicle status, wherein the vehicle status includes normal braking status, slip status, slip recovery process status, slip recovery completed status, and slip recovery timeout status.

[0040] According to a third aspect of the present invention, an electronic device is provided, including a processor and a memory, wherein the memory stores a program or instructions executable by the processor, and the program or instructions, when executed by the processor, implement the steps of the anti-lock braking control method for a brake-by-wire system according to the first aspect of the present invention.

[0041] According to a fourth aspect of the present invention, a vehicle is provided, including an electronic device as described in the third aspect of the present invention.

[0042] The beneficial effects of this invention are as follows: By employing three-wheel low-selection logic, second-order FIR filtering combined with slope limiting, and a multi-parameter state switching mechanism, this invention effectively solves the stability problem of single-path control in brake-by-wire systems, while simultaneously meeting ASIL-D level functional safety requirements. This method offers advantages such as high control precision, fast response speed, and strong robustness, significantly improving vehicle braking safety and efficiency, and ensuring the safe and reliable operation of brake-by-wire systems. Attached Figure Description

[0043] Figure 1 This is a flowchart of the anti-lock braking control method for a brake-by-wire system in an embodiment of the present invention. Detailed Implementation

[0044] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0045] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0046] Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0047] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0048] In the specification of this invention, the terms "first" and "second" may explicitly or implicitly include one or more of the same feature. In the description of this invention, unless otherwise stated, "multiple" means two or more. Furthermore, in the specification, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0049] like Figure 1 As shown in the figure, this embodiment introduces an anti-lock braking control method for a brake-by-wire system, including steps 1100-1400.

[0050] Step 1100: Obtain the first set of wheel speeds, which includes the wheel speeds of all wheels.

[0051] The wheel speed of each wheel can be obtained using wheel speed sensors corresponding to each wheel. For four-wheeled passenger vehicles, data from all four wheel speed sensors is collected.

[0052] Step 1200: Determine the reference vehicle speed based on the first set of wheel speeds.

[0053] Traditional ABS systems typically use the average or maximum wheel speed of all four wheels as the reference speed. However, in brake-on-line systems, because only one braking pressure can be controlled, this method of calculating the reference speed is susceptible to single-wheel malfunctions or wheel lock-up, leading to system misjudgments. For example, during high-speed braking, if a wheel's speed is significantly lower than other wheels due to sensor malfunction or lock-up, the reference speed calculation of traditional ABS will introduce a large deviation, thus affecting the accuracy of slip ratio control.

[0054] Specifically, step 1200 includes steps 1210-1240.

[0055] Step 1210: Determine a second set of wheel speeds based on the first set of wheel speeds. The second set of wheel speeds includes all wheel speeds in the first set of wheel speeds except for the minimum wheel speed.

[0056] For example, in a four-wheeled passenger vehicle, the wheel speed of wheel 1 is... The wheel speed of wheel 2 is The wheel speed of wheel 3 is The wheel speed of wheel 4 is Sort the wheel speeds of the four wheels in descending order, where Let the minimum wheel speed be the set of wheel speeds. Then the second set of wheel speeds includes... , , .

[0057] Step 1220: Obtain the vertical load of all wheels corresponding to the second set of wheel speeds.

[0058] For each wheel corresponding to each wheel speed in the second wheel speed set, the vertical load is obtained separately. For example, for the four-wheeled passenger vehicle mentioned above, the vertical loads of wheel 1, wheel 2, and wheel 3 are obtained separately. The vertical loads of the wheels can be obtained using relevant detection equipment installed on the vehicle.

[0059] Step 1230: Determine the weight of each wheel based on the vertical load.

[0060] The greater the vertical load, the greater the weight. Specifically, the weight is the proportion of each wheel's vertical load to the total vertical load, which is the sum of the vertical loads of all wheels corresponding to the second wheel speed set. For example, for the four-wheeled passenger vehicle mentioned above, the total vertical load is the sum of the vertical loads of wheel 1, wheel 2, and wheel 3.

[0061] Step 1240: Calculate the reference vehicle speed based on the weight of each wheel and the second set of wheel speeds.

[0062] The reference speed is calculated by weighting each wheel according to its weight and corresponding wheel speed. For the four-wheeled passenger vehicle mentioned above, the formula for calculating the reference speed is:

[0063] ;

[0064] in, For reference vehicle speed, The vertical load on wheel 1 is... The vertical load on wheel 2 is... The vertical load is for wheel 3.

[0065] Minimum wheel speed is excluded when calculating reference speed to avoid interference from single wheel lock-up or malfunction, thus ensuring the accuracy of reference speed.

[0066] Step 1300: Calculate the slip ratio based on the reference vehicle speed.

[0067] The formula for calculating slip ratio is as follows:

[0068] ;

[0069] in, For slip ratio, The angular velocity of the wheel. This is the rolling radius of the wheel.

[0070] Step 1400: Adjust the braking pressure according to the slip ratio and vehicle status, wherein the vehicle status includes normal braking status, slip status, slip recovery process status, slip recovery completed status, and slip recovery timeout status.

[0071] Specifically, step 1400 includes: implementing decompression control when the vehicle is in the slip state; implementing pressure holding control when the vehicle is in the slip recovery process state; implementing pressure boosting control when the vehicle is in the slip recovery completed state; and shutting off control when the vehicle is in the slip recovery timeout state.

[0072] Under normal braking conditions, this indicates a low slip ratio, which is within a safe range and poses no risk of brake lockup. In this state, ABS intervention is unnecessary, and braking pressure can be adjusted based on the brake pedal signal.

[0073] In a slip state, it indicates a high slip ratio, exceeding the set threshold. At this point, pressure relief control needs to be implemented to reduce braking pressure, allowing wheel speed to recover and preventing wheel lockup.

[0074] During the slip recovery process, it indicates that the slip ratio has begun to decrease but has not yet fully recovered. At this point, pressure holding control is required to maintain a constant pressure and allow the slip ratio to continue decreasing.

[0075] Once slip recovery is complete, it indicates that the slip ratio has returned to a safe range. At this point, pressurization control is required to restore pressure and re-establish braking force.

[0076] A slip recovery timeout indicates that the slip ratio remains too high and the slip has not been disengaged for an extended period. In this case, a forced voltage reduction is required, triggering a fault alarm.

[0077] In this embodiment, step 1400 further includes:

[0078] Under various vehicle conditions, the PD control algorithm is used to adjust the braking pressure:

[0079] ;

[0080] in, For brake pressure adjustment amount, This is the proportionality coefficient. The differential coefficients are... For slip ratio, For time.

[0081] Set the proportional coefficient according to actual needs. Scope:

[0082] ;

[0083] like Too small (less than 0.5), the response is slow and cannot quickly suppress slippage; if Too high a value (greater than 1.2) can easily cause pressure oscillations, and may even lead to repeated wheel lock-up and release vibrations.

[0084] In the slip state, take the larger value. This achieves rapid pressure reduction. During the slip recovery process, the smaller value is taken. To avoid excessive pressure reduction, take an intermediate value after the slip recovery is complete, for example... Slowly increase the pressure.

[0085] Set the differential coefficients Scope:

[0086] ;

[0087] The differential term is sensitive to the rate of change of the slip ratio. If Excessive values ​​(greater than 0.3) will amplify noise, causing frequent pressure fluctuations. If... If the value is too small (less than 0.1), it cannot effectively predict the slippage trend.

[0088] During the slip recovery process, a stronger differential action is needed to stabilize the pressure. In the slip state, the differential term can assist in a fast response; take When the slip recovery is complete, the differential term should decrease. To avoid overshooting during voltage boost.

[0089] In this embodiment, before calculating the slip ratio based on the reference vehicle speed, the method further includes: performing a second-order FIR low-pass filter on the reference vehicle speed; and applying a slope limit to the filtered reference vehicle speed.

[0090] The filter cutoff frequency is set to 15Hz, and the filter output is:

[0091] ;

[0092] in, The filtered reference vehicle speed. The reference vehicle speed for the current sampling period. The reference vehicle speed for the previous sampling period. This is the reference vehicle speed for the first two sampling periods.

[0093] Slope limits are imposed on the reference vehicle speed, including:

[0094] ;

[0095] in, To mitigate gravitational acceleration, slope limiting is used to prevent drastic fluctuations in the reference vehicle speed, thus ensuring the stability of the control system.

[0096] The rate of change of the filtered reference vehicle speed is calculated. If it exceeds +1.2g, it is limited to +1.2g. If it is below -1.2g, it is limited to -1.2g. The limited reference vehicle speed is then obtained by inverse integration.

[0097] The vehicle's actual maximum deceleration is limited by the road surface adhesion coefficient; 1.2g exceeds the conventional tire-road adhesion limit, but a redundancy margin is retained, and abnormal sensor fluctuations can be detected. By limiting the slope, it prevents sudden changes in reference vehicle speed caused by instantaneous abnormalities in wheel speed signals (such as electromagnetic interference or sensor short circuits), thus avoiding erroneous slip ratios. Simultaneously, it ensures that changes in reference vehicle speed conform to vehicle dynamics.

[0098] This embodiment uses a second-order FIR low-pass filter combined with slope limiting to suppress noise while maintaining dynamic response characteristics, without requiring complex parameter adjustments.

[0099] In this embodiment, the conditions for switching vehicle states include:

[0100] When the vehicle is in a normal braking state, if the slip ratio is greater than a first slip ratio threshold, the slip ratio difference is greater than a first slip ratio difference threshold, and the first duration is greater than a first time threshold, the vehicle state switches from the normal braking state to the slip state. The first duration is the duration during which the slip ratio is greater than the first slip ratio threshold and the slip ratio difference is greater than the first slip ratio difference threshold. The slip ratio difference is the slip ratio change rate.

[0101] When the vehicle is in the slip state, if the slip ratio is less than the second slip ratio threshold, the slip ratio difference is less than the second slip ratio difference threshold, and the second duration is greater than the second time threshold, the vehicle state switches from the slip state to the slip recovery process state. The second duration is the duration during which the slip ratio is less than the second slip ratio threshold and the slip ratio difference is less than the second slip ratio difference threshold.

[0102] When the vehicle is in the slip state, if the slip rate is greater than the second slip rate threshold and the third duration is greater than the third time threshold, the vehicle state switches from the slip state to the slip recovery timeout state, and the third duration is the duration during which the slip rate is greater than the second slip rate threshold.

[0103] When the vehicle is in the slip recovery process state, if the slip ratio is less than the second slip ratio threshold and the fourth duration is greater than the second time threshold, the vehicle state switches from the slip recovery process state to the slip recovery completed state, and the fourth duration is the duration during which the slip ratio is less than the second slip ratio threshold.

[0104] If the vehicle is in the state of complete slip recovery and the duration exceeds a fourth time threshold, the vehicle state switches from the state of complete slip recovery to the state of normal braking.

[0105] The first slip ratio threshold is 25%, the first slip ratio difference threshold is +0.1g / s, the first time threshold is 500ms, the second slip ratio threshold is 15%, the second slip ratio difference threshold is -0.1g / s, the second time threshold is 200ms, the third time threshold is 2000ms, and the fourth time threshold is 1500ms.

[0106] If state transitions rely solely on a single threshold for the slip ratio, the following problems will occur:

[0107] False triggering: Due to brief fluctuations in wheel speed signals caused by uneven road surfaces, sensor noise, etc., the slip ratio may momentarily exceed the threshold, causing the system to frequently and falsely enter ABS control, interfering with normal braking;

[0108] Control lag: When the slip ratio reaches 25%, the wheels may already be close to deep lock-up, and the intervention time is too late;

[0109] State oscillation: The slip ratio fluctuates back and forth around the threshold, causing the system to frequently switch between boosting and depressurization, resulting in strong fluctuations in braking force and poor driving comfort.

[0110] This embodiment introduces slip ratio difference and duration in addition to slip ratio. Slip ratio is used to determine the degree of danger, avoiding misjudgment of ABS lockup due to large slip ratio difference when slip ratio is very low, and reducing unnecessary ABS intervention.

[0111] The slip ratio difference is the rate of change of slip ratio. It reflects the speed and trend of slip ratio change, indicating whether the slip ratio is rapidly deteriorating. It's crucial to avoid blindly reducing pressure when the slip ratio is high but has stabilized. For example, on icy or snowy roads, if the slip ratio is 30% but the slip ratio difference is close to 0, the pressure reduction effect will be poor; the pressure should be maintained or adjusted slowly. The slip ratio difference is used to predict trends; a large slip ratio difference indicates that the slip is about to become deeply stuck, requiring immediate intervention.

[0112] Duration is used to ensure that the abnormal state is a continuous reality, rather than transient noise or occasional spikes. High-frequency noise may exist in the wheel speed signal due to factors such as gear ring vibration and electromagnetic interference, which can cause anomalies. Duration helps avoid misjudgments. Furthermore, it prevents erroneous ABS activation caused by transient wheel speed fluctuations due to minor road surface bumps.

[0113] The system enters the slip state when the slip ratio exceeds 25%, the slip ratio difference exceeds +0.1g / s, and the duration exceeds 500ms.

[0114] In the slip state, when the slip ratio is less than 15%, the slip ratio difference is less than -0.1g / s, and the duration is greater than 200ms, the system enters the slip recovery process state.

[0115] In the slip state, if the slip rate is greater than 15% and the duration exceeds 2000ms, the system enters the slip recovery timeout state.

[0116] During the slip recovery process, when the slip ratio is less than 15% and the duration exceeds 200ms, the system enters the slip recovery completed state.

[0117] Once the slip recovery is complete, the system returns to normal braking state after a duration exceeding 1500ms.

[0118] If only the slip ratio is used for state switching, there will be a problem that the slip ratio will be triggered when it briefly exceeds 25% due to noise. At the same time, it is impossible to distinguish whether the slip ratio is deteriorating rapidly or changing slowly, which may lead to intervention that is too late or too early.

[0119] If only slip ratio and slip ratio difference are used without duration filtering, then a noise spike of only 50ms (slip ratio 30%, slip ratio difference + 0.15g / s) will cause false triggering.

[0120] Using only slip ratio and duration is insufficient to determine the deterioration trend. Slow fluctuations in slip ratio around 25% can also lead to false triggering. In this case, the wheels do not actually lock up quickly, and applying decompression control after triggering will result in excessive loss of braking force.

[0121] If only slip ratio difference and duration are used, it may be misjudged as wheel lock-up when the slip ratio is very low (e.g., 10%) but the slip ratio difference is large (due to instantaneous fluctuations in wheel speed).

[0122] This embodiment uses slip ratio, slip ratio difference, and duration for joint judgment to ensure that the system only enters slip state under truly dangerous, continuously deteriorating, and non-transient noise conditions, thereby achieving a balance of timeliness, accuracy, and stability. By switching between multiple parameters, false triggers are effectively reduced, and the system's adaptability to complex road conditions is improved.

[0123] This invention provides an innovative redundant anti-lock braking control method for brake-by-wire systems. By employing three-wheel low-select logic, second-order FIR filtering combined with slope limiting, and a multi-parameter state switching mechanism, it effectively solves the stability problem of single-path control in brake-by-wire systems while meeting ASIL-D functional safety requirements. This method offers advantages such as high control precision, fast response speed, and strong robustness, significantly improving vehicle braking safety and efficiency, and ensuring the safe and reliable operation of brake-by-wire systems.

[0124] This embodiment describes an apparatus for an anti-lock braking control method for a brake-by-wire system according to any embodiment of the present invention, comprising:

[0125] The wheel speed acquisition module is used to acquire a first wheel speed set, which includes the wheel speeds of all wheels;

[0126] The vehicle speed calculation module is used to determine a reference vehicle speed based on the first set of wheel speeds.

[0127] The slip ratio calculation module is used to calculate the slip ratio based on the reference vehicle speed;

[0128] The pressure calculation module is used to adjust the braking pressure according to the slip ratio and vehicle status, wherein the vehicle status includes normal braking status, slip status, slip recovery process status, slip recovery completed status, and slip recovery timeout status.

[0129] This embodiment introduces an electronic device, including a processor and a memory. The memory stores programs or instructions that can be executed by the processor. When the program or instructions are executed by the processor, they implement the steps of the anti-lock braking control method for a brake-by-wire system according to any embodiment of the present invention.

[0130] This embodiment describes a vehicle that includes an electronic device as described in the above embodiments of the present invention.

[0131] While specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention.

[0132] Those skilled in the art will recognize that the modules and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0133] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and equipment can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0134] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0135] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of the embodiments of the present invention, depending on actual needs.

[0136] In addition, the functional modules in the embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0137] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0138] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

[0139] It should be understood that the sequence numbers of the steps in the invention's content and embodiments do not absolutely imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention. The foregoing description of embodiments of this disclosure has been provided for illustrative and descriptive purposes. The foregoing description is not exhaustive and is not intended to limit this disclosure to the exact form disclosed. Various modifications and variations may exist based on the foregoing teachings, or various modifications and variations may be derived from the practice of this disclosure. These embodiments were chosen and described to illustrate the principles of this disclosure and its practical application, so that those skilled in the art can utilize this disclosure in various implementations and modifications suitable for the specific purpose of the concept.

Claims

1. A method for anti-lock braking control of a brake-by-wire system, characterized in that, include: Obtain the first set of wheel speeds, which includes the wheel speeds of all wheels; The reference vehicle speed is determined based on the first set of wheel speeds; Calculate the slip ratio based on the reference vehicle speed; Adjust the braking pressure according to the slip ratio and vehicle status, wherein the vehicle status includes normal braking status, slip status, slip recovery process status, slip recovery completed status, and slip recovery timeout status; Determining the reference vehicle speed based on the first set of wheel speeds includes: A second set of wheel speeds is determined based on the first set of wheel speeds, and the second set of wheel speeds includes all wheel speeds in the first set of wheel speeds except for the minimum wheel speed. Obtain the vertical load of all wheels corresponding to the second set of wheel speeds; The weight of each wheel is determined based on the vertical load. The reference vehicle speed is calculated based on the weight of each wheel and the second set of wheel speeds; The step of adjusting the braking pressure based on the slip ratio and vehicle condition includes: When the vehicle is in the slip state, decompression control is implemented; When the vehicle is in the slip recovery process state, pressure holding control is implemented; When the vehicle is in the state of complete slip recovery, boost control is implemented; When the vehicle is in the slip recovery timeout state, control is turned off.

2. The anti-lock braking control method for a brake-by-wire system according to claim 1, characterized in that, Before calculating the slip ratio based on the reference vehicle speed, the method further includes: The reference vehicle speed is subjected to a second-order FIR low-pass filter; Slope limiting is applied to the filtered reference vehicle speed.

3. The anti-lock braking control method for a brake-by-wire system according to claim 1, characterized in that, The conditions for switching vehicle states include: When the vehicle is in a normal braking state, if the slip ratio is greater than a first slip ratio threshold, the slip ratio difference is greater than a first slip ratio difference threshold, and the first duration is greater than a first time threshold, the vehicle state switches from the normal braking state to the slip state, wherein the first duration is the duration during which the slip ratio is greater than the first slip ratio threshold and the slip ratio difference is greater than the first slip ratio difference threshold; When the vehicle is in the slip state, if the slip ratio is less than the second slip ratio threshold, the slip ratio difference is less than the second slip ratio difference threshold, and the second duration is greater than the second time threshold, the vehicle state switches from the slip state to the slip recovery process state. The second duration is the duration during which the slip ratio is less than the second slip ratio threshold and the slip ratio difference is less than the second slip ratio difference threshold. When the vehicle is in the slip state, if the slip rate is greater than the second slip rate threshold and the third duration is greater than the third time threshold, the vehicle state switches from the slip state to the slip recovery timeout state, and the third duration is the duration during which the slip rate is greater than the second slip rate threshold; When the vehicle is in the slip recovery process state, if the slip ratio is less than the second slip ratio threshold and the fourth duration is greater than the second time threshold, the vehicle state switches from the slip recovery process state to the slip recovery completed state, and the fourth duration is the duration during which the slip ratio is less than the second slip ratio threshold; If the vehicle is in the state of complete slip recovery and the duration exceeds a fourth time threshold, the vehicle state switches from the state of complete slip recovery to the state of normal braking.

4. The anti-lock braking control method for a brake-by-wire system according to claim 3, characterized in that, The first slip ratio threshold is 25%, the first slip ratio difference threshold is +0.1g / s, the first time threshold is 500ms, the second slip ratio threshold is 15%, the second slip ratio difference threshold is -0.1g / s, the second time threshold is 200ms, the third time threshold is 2000ms, and the fourth time threshold is 1500ms.

5. The anti-lock braking control method for a brake-by-wire system according to claim 1, characterized in that, The method of adjusting the braking pressure according to the slip ratio and vehicle condition further includes: Under various vehicle conditions, the PD control algorithm is used to adjust the braking pressure: ； in, For brake pressure adjustment amount, This is the proportionality coefficient. These are the differential coefficients. For slip ratio, For time, This represents the slip ratio difference.

6. An apparatus for an anti-lock braking control method for a brake-by-wire system according to any one of claims 1-5, characterized in that, include: The wheel speed acquisition module is used to acquire a first wheel speed set, which includes the wheel speeds of all wheels; The vehicle speed calculation module is used to determine a reference vehicle speed based on the first set of wheel speeds. The slip ratio calculation module is used to calculate the slip ratio based on the reference vehicle speed; The pressure calculation module is used to adjust the braking pressure according to the slip ratio and vehicle status, wherein the vehicle status includes normal braking status, slip status, slip recovery process status, slip recovery completed status, and slip recovery timeout status.

7. An electronic device, characterized in that, It includes a processor and a memory, wherein the memory stores a program or instructions that can be executed by the processor, and when the program or instructions are executed by the processor, they implement the steps of the anti-lock braking control method for a brake-by-wire system as described in any one of claims 1-5.

8. A vehicle, characterized in that, Includes the electronic device described in claim 7.

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