An active control method for single-wheel failure of an EMB brake-by-wire system

Abstract

The application discloses an EMB (electronic mechanical brake) single-wheel failure active control method, and relates to the technical field of automobile chassis brake-by-wire technology.The application realizes real-time monitoring of the four-wheel EMB actuator state of a vehicle, obtains the brake pedal stroke, and calculates the total target braking force of the vehicle;according to the position of the failure single wheel, the single-wheel failure mode is determined, and the single-wheel failure mode includes the front axle single-wheel failure mode and the rear axle single-wheel failure mode;based on the wheel failure mode determination result, the multi-actuator is used for collaborative torque arbitration, and the active control of the single-wheel failure is realized.The application can realize the deviation suppression and the spinout protection without the intervention of the driver, and can balance the braking efficiency and the driving stability, meets the functional safety requirements of the EMB system, and is suitable for distributed electric drive vehicles and high-order automatic driving scenes.

Description

Technical Field

[0001] This invention relates to the field of automotive chassis steer-by-wire technology, and in particular to an active control method for single-wheel failure in an EMB steer-by-wire system. Background Technology

[0002] The Electromechanical Braking (EMB) system uses four independent motors to directly drive the brake calipers, eliminating hydraulic lines, master cylinders, and vacuum boosters. It has advantages such as fast response, high control precision, flexible layout, and easy integration, and is a core actuator for next-generation drive-by-wire chassis and L3 and above advanced autonomous driving.

[0003] Because EMB lacks traditional hydraulic backup, single-wheel braking failure can lead to severe asymmetry in braking force between the left and right wheels, causing violent yaw moments. A single-point failure in the front wheel will generate a huge yaw moment, causing the vehicle to veer violently towards the side with normal braking. A single-point failure in the rear wheel will result in excessive braking force on the side with normal braking, making it very easy for the rear wheel to lock up or exceed the adhesion circle limit, causing the rear axle to lose lateral traction and triggering a fishtail.

[0004] In existing technologies, the following strategy is used when a unilateral EMB failure is detected:

[0005] 1) Relying on driver correction: prompting the driver to counter-steer the wheel, correcting the deviation through driver intervention.

[0006] 2) Simple PID boost: In order to ensure deceleration, the clamping force of the caliper on the opposite side (normal side) is directly increased.

[0007] However, existing technologies have the following obvious drawbacks:

[0008] 1. Response lag: When a vehicle is traveling at high speed, the yaw moment generated by the failure of a single wheel is extremely large, and the driver's reaction time is often insufficient to prevent the vehicle from running off the lane.

[0009] 2. Stability risk: On low-friction surfaces, if the steering system's capacity is not considered, blindly increasing the braking force on the opposite side will drastically increase the yaw moment, directly causing the vehicle to fishtail.

[0010] 3. Waste of resources: The braking system is used only for adjustment, without utilizing the increasingly popular electric drive capability of electric vehicles to fill the braking force gap.

[0011] Therefore, there is an urgent need for a single-round active failure control method for EMB systems to solve the existing technical problems. Summary of the Invention

[0012] This invention aims to solve at least one of the technical problems existing in the prior art, and proposes an active control method for single-wheel failure in EMB brake-by-wire systems.

[0013] This invention provides an active control method for single-wheel failure in an EMB brake-by-wire system, comprising:

[0014] Real-time monitoring of the EMB actuator status of the vehicle's four wheels, acquisition of brake pedal travel, and calculation of the vehicle's total target braking force;

[0015] The failure mode of a single wheel is determined based on its location. The failure modes include the front axle single wheel failure mode and the rear axle single wheel failure mode.

[0016] Based on the wheel failure mode determination results, multiple actuators are used for coordinated torque arbitration to achieve active control over single wheel failure.

[0017] Furthermore, methods for obtaining brake pedal travel and calculating the total target braking force of the vehicle include:

[0018] Based on the driver's brake pedal travel, the pedal travel is normalized to obtain the pedal travel normalization result.

[0019] Based on the pedal travel normalization result and vehicle speed, the total target deceleration requirement of the vehicle is obtained by using the vehicle calibration mapping function.

[0020] Calculate the total target braking force of the vehicle based on the total target deceleration requirement of the vehicle.

[0021] Furthermore, the formula for normalizing the brake pedal travel is:

[0022]

[0023] in, This is the pedal dead zone; Maximum travel distance;

[0024] The formula for calculating the total target deceleration requirement of the vehicle is: ;in, To meet the overall target deceleration requirement of the vehicle, For vehicle speed, For vehicle calibration mapping functions;

[0025] The formula for calculating the total target braking force of a vehicle is: ;in The total target braking force for the vehicle. For vehicle quality.

[0026] Furthermore, when the single-wheel failure mode is the front axle single-wheel failure mode, multiple actuators are used for coordinated torque arbitration to achieve active control of single-wheel failure. Specific methods include:

[0027] Calculate the reference braking force and yaw moment of the opposite normal wheel;

[0028] Obtain the maximum available regenerative braking force output from the failed wheel drive motor and calculate the yaw moment residual.

[0029] The EPS system outputs an active self-correcting torque based on the yaw force residual.

[0030] When the EPS system torque is insufficient, the braking force of the normal wheel on the opposite side is dynamically limited, and the upper limit of the braking force of the normal wheel on the opposite side is calculated.

[0031] The current braking force of the rear wheel is obtained. Based on the maximum available regenerative braking force, the upper limit of the braking force of the opposite normal wheel, and the current braking force of the rear wheel, the missing braking force value is calculated, and the missing braking force value is compensated.

[0032] Furthermore, the reference braking force and yaw moment of the opposite normal wheel are calculated, specifically using the following methods:

[0033] Based on the vehicle's total target braking force Calculate the braking force output of the normal wheel on the opposite side. = Then the reference braking force and yaw moment of the opposite normal wheel ;in, This is the distance between the wheels.

[0034] Furthermore, the maximum available regenerative braking force output by the failed wheel drive motor is obtained, and the yaw moment residual is calculated. Specific methods include:

[0035] Query the maximum available regenerative braking force of the failed wheel drive motor Calculate the remaining yaw moment residual value. If the remaining yaw moment residual value If the failed wheel drive motor outputs regenerative braking force... If the remaining yaw moment residual value Then the maximum available regenerative braking force will be output. And request the EPS system to fill the residuals.

[0036] Furthermore, the EPS system outputs an active self-correcting torque based on the yaw force residual. Specific methods include:

[0037] The calculated residuals This signal is sent as a feedforward signal to the EPS system, and the maximum active self-aligning torque that the EPS system can currently provide is queried. ;

[0038] and Size, if Then based on residual value Output; if Then use the maximum value. It outputs power and limits the braking force on the normal wheel on the opposite side.

[0039] Furthermore, when the EPS system torque is insufficient, the braking force of the opposite normal wheel is dynamically limited, and the upper limit of the braking force of the opposite normal wheel is calculated, specifically including:

[0040] when When this occurs, the braking force of the opposite normal wheel is reduced; the maximum braking force of the opposite normal wheel after reduction is:

[0041]

[0042] in, The maximum available regenerative braking force of the failed wheel drive motor. This represents the maximum active self-aligning torque that the EPS system can currently provide.

[0043] Furthermore, based on the maximum available regenerative braking force, the upper limit of the braking force of the opposite normal wheel, and the current braking force of the rear wheel, a missing braking force value is calculated, and the missing braking force value is compensated. Specific methods include:

[0044] Obtain the current braking force of the rear wheels , ,in This is the braking torque at the rear wheel end. ,in This refers to the torque of the rear wheel brake motor. For mapping functions;

[0045] After executing coordinated control and limiting the braking force of the opposite normal wheel, the controller calculates the current actual total braking force in real time. :

[0046]

[0047] in, This is the upper limit of the normal braking force on the opposite side. To maximize available regenerative braking force, The current braking force for the rear wheels;

[0048] Calculate the missing value of braking force :

[0049]

[0050] in, The total target braking force for the vehicle. The calculated actual total braking force is the current actual braking force. The two wheels on the rear axle are allocated to ensure that the actual deceleration of the vehicle is as close as possible to the driver's expected value.

[0051] Furthermore, when the single-wheel failure mode is the rear-wheel failure mode, multiple actuators are used for coordinated torque arbitration to achieve active control over single-wheel failure. Specific methods include:

[0052] Controlling coaxiality: Limiting the braking force output of the rear wheel on the normal side, while lowering its slip ratio threshold to ensure lateral grip and prevent left and right wheel torque imbalance and fishtailing;

[0053] Compensation for axle misalignment: All the braking force that is missing or restricted on the rear axle is transferred to the more stable front axle to make up for it, thus supplementing the vehicle's braking deceleration without causing loss of control;

[0054] The EPS system works in conjunction: it only outputs a small correction torque to stabilize vehicle yaw and optimize driver handling.

[0055] This invention discloses an active control method for single-wheel failure in an EMB (Electronic Brake-by-Wire) system. It involves real-time monitoring of the EMB actuator status of all four wheels of the vehicle to obtain the brake pedal travel and calculate the total target braking force. Based on the location of the failed wheel, the method determines the single-wheel failure mode, including front axle and rear axle single-wheel failure modes. Based on the wheel failure mode determination results, multiple actuators are used for coordinated torque arbitration to achieve active control of the single-wheel failure. This invention achieves lane departure suppression and skid protection without driver intervention, balancing braking performance and driving stability, meeting the functional safety requirements of EMB systems, and is applicable to distributed electric drive vehicles and high-level autonomous driving scenarios.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] 1. Laying the foundation for EMB mass production safety: For EMB systems without hydraulic backup, a low-cost software solution meets the ISO26262ASIL-D functional safety requirements, solves the key threshold of single-point failure tolerance, becomes the core safety pass for EMB mass production, and helps automakers quickly mass-produce drive-by-wire chassis.

[0058] 2. Supports advanced autonomous driving safety: Adaptable to L3 / L4 level autonomous driving scenarios, it can achieve closed-loop chassis control without driver intervention, eliminating the reliance on manual "counter-steering", becoming an essential component of the autonomous driving chassis safety architecture, and matching the huge market demand.

[0059] 3. Enhance the premium of high-end electric vehicles: Perfectly compatible with multi-motor and distributed drive architecture, it can be marketed as an "extreme safety mode" or "track-level fault-tolerant control" function, strengthening the technological premium and brand image of high-performance electric vehicles. Attached Figure Description

[0060] Figure 1A flowchart illustrating an active control method for single-wheel failure in an EMB brake-by-wire system, provided by an embodiment of the present invention;

[0061] Figure 2 This is a flowchart illustrating an optional specific implementation method of step S100 in an embodiment of the present invention;

[0062] Figure 3 This is a flowchart illustrating an optional specific implementation method of step S300 in an embodiment of the present invention. Detailed Implementation

[0063] To enable those skilled in the art to better understand the technical solutions of the present invention, exemplary embodiments of the present invention are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to aid understanding. These should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.

[0064] Where there is no conflict, the various embodiments of the present invention and the features thereof may be combined with each other.

[0065] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0066] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded. Terms such as “connected” or “linked” are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect.

[0067] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art and the invention, and will not be interpreted as having an idealized or overly formal meaning unless expressly so defined herein.

[0068] In the technical solution of this invention, the collection, storage, use, processing, transmission, provision, and disclosure of user personal information all comply with relevant laws and regulations and do not violate public order and good morals. The use of user data in this technical solution follows relevant national laws and regulations (e.g., the "Information Security Technology - Personal Information Security Specification"). For example: appropriate measures are taken for personal information access control; restrictions are imposed on the display of personal information; the purpose of using personal information does not exceed the scope of direct or reasonable association; and explicit identity targeting is eliminated when using personal information to avoid precisely locating a specific individual.

[0069] To address at least one of the technical problems existing in the aforementioned related technologies, the present invention provides an active control method for single-wheel failure in an EMB brake-by-wire system.

[0070] This implementation discloses an active control method for single-wheel failure in an EMB brake-by-wire system, such as... Figure 1 ,include:

[0071] S100. Real-time monitoring of the status of the four-wheel EMB actuators of the vehicle, obtaining the brake pedal travel, and calculating the total target braking force of the vehicle; specifically, real-time acquisition of the clamping force, motor current, and position feedback signals of the four-wheel EMB actuators to determine whether a single wheel failure has occurred.

[0072] In this embodiment, the method for obtaining the brake pedal travel and calculating the total target braking force of the vehicle is as follows: Figure 2 include:

[0073] S101. Based on the driver's brake pedal travel, normalize the pedal travel to obtain the pedal travel normalization result;

[0074] Specifically, the formula for normalizing the brake pedal travel is:

[0075]

[0076] in, This is the pedal dead zone; Maximum travel distance;

[0077] S102. Based on the pedal travel normalization result and vehicle speed, the total target deceleration requirement of the vehicle is obtained by using the vehicle calibration mapping function;

[0078] Specifically, the formula for calculating the total target deceleration requirement of the vehicle is as follows: ;in, To meet the overall target deceleration requirement of the vehicle, For vehicle speed, For vehicle calibration mapping functions;

[0079] S103. Calculate the total target braking force of the vehicle based on the total target deceleration requirement. Specifically, the formula for calculating the total target braking force of the vehicle is: ;in The total target braking force for the vehicle. For vehicle quality.

[0080] S200. Determine the single-wheel failure mode based on the location of the failed single wheel, wherein the single-wheel failure mode includes the front axle single-wheel failure mode and the rear axle single-wheel failure mode;

[0081] Specifically, the chassis domain controller classifies failures into two categories based on fault codes and wheel positions: Mode I: single front axle wheel failure, with the core risks being deviation and large yaw moment; Mode II: single rear axle wheel failure, with the core risks being fishtailing and insufficient lateral adhesion.

[0082] S300. Based on the wheel failure mode determination results, multiple actuators are used for coordinated torque arbitration to achieve active control over single wheel failure.

[0083] In this embodiment, when the single-wheel failure mode is the front axle single-wheel failure mode, multiple actuators are used for coordinated torque arbitration to achieve active control of single-wheel failure, such as... Figure 3 Specific methods include:

[0084] S301. Calculate the reference braking force and yaw moment of the opposite normal wheel; for example, when a single front axle wheel fails, taking the failure of the left front wheel FL as an example, calculate the reference braking force and yaw moment of the opposite normal wheel. The specific method includes:

[0085] Based on the vehicle's total target braking force Calculate the braking force output of the normal wheel on the opposite side. = Then the reference braking force and yaw moment of the opposite normal wheel ;in, This is the distance between the wheels.

[0086] S302. Obtain the maximum available regenerative braking force output by the failed wheel drive motor and calculate the yaw moment residual; In this embodiment, the specific method for obtaining the maximum available regenerative braking force output by the failed wheel drive motor and calculating the yaw moment residual includes:

[0087] Query the maximum available regenerative braking force of the failed wheel drive motor Calculate the remaining yaw moment residual value. If the remaining yaw moment residual value If the failed wheel drive motor outputs regenerative braking force... If the remaining yaw moment residual value Then the maximum available regenerative braking force will be output. And request the EPS system to fill the residuals.

[0088] S303. The EPS system outputs an active aligning torque based on the yaw force residual; in this embodiment, the EPS system outputs an active aligning torque based on the yaw force residual, and the specific method includes:

[0089] The calculated residuals This signal is sent as a feedforward signal to the EPS system, and the maximum active self-aligning torque that the EPS system can currently provide is queried. ;

[0090] and Size, if Then based on residual value Output; if Then use the maximum value. It outputs power and limits the braking force on the normal wheel on the opposite side.

[0091] S304. When the EPS system torque is insufficient, the braking force of the opposite normal wheel is dynamically limited, and the upper limit of the braking force of the opposite normal wheel is calculated; in this embodiment, when the EPS system torque is insufficient, the braking force of the opposite normal wheel is dynamically limited, and the upper limit of the braking force of the opposite normal wheel is calculated, specifically including:

[0092] when When this occurs, the braking force of the opposite normal wheel is reduced; the maximum braking force of the opposite normal wheel after reduction is:

[0093]

[0094] in, The maximum available regenerative braking force of the failed wheel drive motor. This represents the maximum active self-aligning torque that the EPS system can currently provide.

[0095] S305. Obtain the current braking force of the rear wheel, calculate the missing braking force value based on the maximum available regenerative braking force, the upper limit of the braking force of the opposite normal wheel, and the current braking force of the rear wheel, and compensate for the missing braking force value.

[0096] In this embodiment, based on the maximum available regenerative braking force, the upper limit of the braking force of the opposite normal wheel, and the current braking force of the rear wheel, a missing braking force value is calculated, and the missing braking force value is compensated. The specific method includes:

[0097] Obtain the current braking force of the rear wheels , ,in This is the braking torque at the rear wheel end. ,in This refers to the torque of the rear wheel brake motor. For mapping functions;

[0098] After executing coordinated control and limiting the braking force of the opposite normal wheel, the controller calculates the current actual total braking force in real time. :

[0099]

[0100] in, This is the upper limit of the normal braking force on the opposite side. To maximize available regenerative braking force, The current braking force for the rear wheels;

[0101] Calculate the missing value of braking force :

[0102]

[0103] in, The total target braking force for the vehicle. The calculated actual total braking force is the current actual braking force. The two wheels on the rear axle are allocated to ensure that the actual deceleration of the vehicle is as close as possible to the driver's expected value.

[0104] To better understand this implementation, the following example illustrates a single wheel failure on the front axle:

[0105] The vehicle was traveling at 100 km / h when the left front wheel EMB failed, and the driver applied moderate braking.

[0106] The system identified FL failure and determined it to be Mode I;

[0107] Calculate the FR reference braking force and yaw moment Myaw;

[0108] The FL drive motor outputs the maximum regenerative braking force, and the EPS compensates for the remaining torque.

[0109] When the EPS torque is insufficient, the FR braking force is dynamically reduced to the safe limit.

[0110] The rear wheels compensate for the braking force gap, allowing the vehicle to decelerate stably in a straight line without veering off course.

[0111] In this embodiment, when the single-wheel failure mode is the rear-wheel failure mode, multiple actuators are used for coordinated torque arbitration to achieve active control of single-wheel failure. The specific method includes:

[0112] Controlling coaxiality: Limiting the braking force output of the rear wheel on the normal side, while lowering its slip ratio threshold to ensure lateral grip and prevent left and right wheel torque imbalance and fishtailing;

[0113] Compensation for axle misalignment: All the braking force that is missing or restricted on the rear axle is transferred to the more stable front axle to make up for it, thus supplementing the vehicle's braking deceleration without causing loss of control;

[0114] The EPS system works in conjunction: it only outputs a small correction torque to stabilize vehicle yaw and optimize driver handling.

[0115] Specifically, the main risk of rear wheel failure is unilateral rear wheel lock-up leading to fishtailing. The EPS system's role is downgraded to auxiliary, with the focus on longitudinal transfer of braking force. For example, in the case of left rear wheel RF failure, specific methods include:

[0116] 1. Adopt a coaxial strategy (right rear wheel RR):

[0117] Strict limiting: Although RR is normal, in order to prevent the left and right torque imbalance from causing a fishtail, the output of RR must be limited;

[0118] Low adhesion logic: Set the slip ratio threshold of RR to be lower than that of normal road surface (e.g., from 20% to 10%) to ensure that RR always maintains sufficient lateral adhesion.

[0119] 2. Off-axis compensation (Front axle FL / FR):

[0120] Load shifting: The braking force missing from the rear axle (including the faulty RL and the actively limited RR) is entirely transferred to the front axle;

[0121] Because the front axle has high braking stability, increasing the front axle braking force will not lead to loss of control, thus compensating for the insufficient total deceleration.

[0122] 3. EPS system provides assistance:

[0123] Because the yaw moment generated by the rear wheels is relatively small, the EPS only needs to apply a small correction torque, which is mainly used to improve the driver's feel and confidence.

[0124] To better understand this embodiment, examples of single-wheel failure on the rear axle will be given below.

[0125] Low-adhesion road surface, left rear wheel EMB failure.

[0126] The system determines it to be Mode II;

[0127] Limit RR braking force and slip ratio to prevent fishtailing;

[0128] The rear axle notch has been completely transferred to the front axle;

[0129] EPS outputs a small corrective torque to maintain directional stability.

[0130] This invention discloses an active control method for single-wheel failure in an EMB (Electronic Brake-by-Wire) system. It involves real-time monitoring of the EMB actuator status of all four wheels of the vehicle to obtain the brake pedal travel and calculate the total target braking force. Based on the location of the failed wheel, the method determines the single-wheel failure mode, including front axle and rear axle single-wheel failure modes. Based on the wheel failure mode determination results, multiple actuators are used for coordinated torque arbitration to achieve active control of the single-wheel failure. This invention achieves lane departure suppression and skid protection without driver intervention, balancing braking performance and driving stability, meeting the functional safety requirements of EMB systems, and is applicable to distributed electric drive vehicles and high-level autonomous driving scenarios.

[0131] Those skilled in the art will understand that all or some of the steps, systems, and apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software can be distributed on a computer-readable storage medium, which may include computer storage media (or non-transitory media) and communication media (or transient media).

[0132] As is known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable program instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), static random access memory (SRAM), flash memory or other memory technologies, portable compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, it is known to those skilled in the art that communication media typically contain computer-readable program instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0133] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0134] The computer program instructions used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions. This electronic circuitry can execute the computer-readable program instructions to implement various aspects of the invention.

[0135] The computer program product described herein can be implemented specifically through hardware, software, or a combination thereof. In one alternative embodiment, the computer program product is specifically embodied in a computer storage medium; in another alternative embodiment, the computer program product is specifically embodied in a software product, such as a software development kit (SDK), etc.

[0136] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0137] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0138] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0139] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0140] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. An active control method for single-wheel failure in an EMB brake-by-wire system, characterized in that, include: Real-time monitoring of the EMB actuator status of the vehicle's four wheels, acquisition of brake pedal travel, and calculation of the vehicle's total target braking force; The failure mode of a single wheel is determined based on its location. The failure modes include the front axle single wheel failure mode and the rear axle single wheel failure mode. Based on the wheel failure mode determination results, multiple actuators are used for coordinated torque arbitration to achieve active control over single wheel failure.

2. The control method according to claim 1, characterized in that, Methods for obtaining brake pedal travel and calculating the total target braking force of the vehicle include: Based on the driver's brake pedal travel, the pedal travel is normalized to obtain the pedal travel normalization result. Based on the pedal travel normalization result and vehicle speed, the total target deceleration requirement of the vehicle is obtained by using the vehicle calibration mapping function. Calculate the total target braking force of the vehicle based on the total target deceleration requirement of the vehicle.

3. The control method according to claim 2, characterized in that, The formula for normalizing brake pedal travel is: ； in, This is the pedal dead zone; Maximum travel distance; The formula for calculating the total target deceleration requirement of the vehicle is: ;in, To meet the overall target deceleration requirement of the vehicle, For vehicle speed, For vehicle calibration mapping functions; The formula for calculating the total target braking force of a vehicle is: ;in The total target braking force for the vehicle. For vehicle quality.

4. The control method according to claim 1, characterized in that, When the single-wheel failure mode is the front axle single-wheel failure mode, multiple actuators are used for coordinated torque arbitration to achieve active control of single-wheel failure. Specific methods include: Calculate the reference braking force and yaw moment of the opposite normal wheel; Obtain the maximum available regenerative braking force output from the failed wheel drive motor and calculate the yaw moment residual. The EPS system outputs an active self-correcting torque based on the yaw force residual. When the EPS system torque is insufficient, the braking force of the normal wheel on the opposite side is dynamically limited, and the upper limit of the braking force of the normal wheel on the opposite side is calculated. The current braking force of the rear wheel is obtained. Based on the maximum available regenerative braking force, the upper limit of the braking force of the opposite normal wheel, and the current braking force of the rear wheel, the missing braking force value is calculated, and the missing braking force value is compensated.

5. The control method according to claim 4, characterized in that, The specific methods for calculating the reference braking force and yaw moment of the opposite normal wheel include: Based on the vehicle's total target braking force Calculate the braking force output of the normal wheel on the opposite side. = Then the reference braking force and yaw moment of the opposite normal wheel ;in, This is the distance between the wheels.

6. The control method according to claim 5, characterized in that, To obtain the maximum available regenerative braking force from the failed wheel drive motor and calculate the yaw moment residual, the specific methods include: Query the maximum available regenerative braking force of the failed wheel drive motor Calculate the residual value of the remaining yaw moment. If the remaining yaw moment residual value If the failed wheel drive motor outputs regenerative braking force If the remaining yaw moment residual value Then the maximum available regenerative braking force will be output. And request the EPS system to fill the residuals.

7. The control method according to claim 6, characterized in that, The EPS system outputs an active corrective torque based on the yaw force residual. Specific methods include: The calculated residuals This signal is sent as a feedforward signal to the EPS system, and the maximum active self-aligning torque that the EPS system can currently provide is queried. ; and Size, if Then based on residual value Output; if Then use the maximum value. It outputs power and limits the braking force on the normal wheel on the opposite side.

8. The control method according to claim 7, characterized in that, When the EPS system torque is insufficient, the braking force of the normal wheel on the opposite side is dynamically limited. The upper limit of the braking force of the normal wheel on the opposite side is calculated, specifically including: when When this occurs, the braking force of the opposite normal wheel is reduced; the maximum braking force of the opposite normal wheel after reduction is: ； in, The maximum available regenerative braking force of the failed wheel drive motor. This represents the maximum active self-aligning torque that the EPS system can currently provide.

9. The control method according to claim 8, characterized in that, Based on the maximum available regenerative braking force, the upper limit of the braking force of the opposite normal wheel, and the current braking force of the rear wheel, a missing braking force value is calculated, and the missing braking force value is compensated. Specific methods include: Obtain the current braking force of the rear wheels , ,in This is the braking torque at the rear wheel end. ,in This refers to the torque of the rear wheel brake motor. For mapping functions; After executing coordinated control and limiting the braking force of the opposite normal wheel, the controller calculates the current actual total braking force in real time. : ； in, This is the upper limit of the normal braking force on the opposite side. To maximize available regenerative braking force, The current braking force for the rear wheels; Calculate the missing value of braking force : ； in, The total target braking force for the vehicle. The calculated actual total braking force is the current actual braking force. The two wheels on the rear axle are allocated to ensure that the actual deceleration of the vehicle is as close as possible to the driver's expected value.

10. The control method according to claim 1, characterized in that, When the single-wheel failure mode is the rear-wheel failure mode, multiple actuators are used for coordinated torque arbitration to achieve active control of single-wheel failure. Specific methods include: Controlling coaxiality: Limiting the braking force output of the rear wheel on the normal side, while lowering its slip ratio threshold to ensure lateral grip and prevent left and right wheel torque imbalance and fishtailing; Compensation for axle misalignment: All the braking force that is missing or restricted on the rear axle is transferred to the more stable front axle to make up for it, thus supplementing the vehicle's braking deceleration without causing loss of control; The EPS system works in conjunction: it only outputs a small correction torque to stabilize vehicle yaw and optimize driver handling.

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