Steer-by-wire fault processing method and device based on distributed driving and vehicle

Abstract

The invention provides a steer-by-wire fault processing method and device based on distributed driving and a vehicle, and relates to the technical field of chassis control, the method can activate a distributed driving system to serve as a cross-system redundant execution unit in an extreme fault scene that a steer-by-wire system is completely invalid and loses steering execution capability, and the steer-by-wire fault processing efficiency is improved. The steering intention of a driver is converted into differential distribution of four-wheel driving torque, so that needed additional yawing torque is generated, the traditional mechanical or electric control steering function is effectively replaced, and active control over vehicle steering is achieved. According to the method, the function safety and controllability of the steer-by-wire vehicle when a key system fails are remarkably improved, the advantage of cooperation of multiple actuators of the electric chassis is fully utilized, high-reliability fault degradation processing is achieved, and the safety of a driver and passengers is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of chassis control technology, and in particular to a method, device and vehicle for handling steer-by-wire faults based on distributed drive. Background Technology

[0002] With the development of automotive intelligence and electrification, steer-by-wire systems, by eliminating the mechanical connection between the steering wheel and steering gear, and enabling flexible adjustment of the steering ratio to improve handling and driving experience, have become a key technology for next-generation intelligent vehicles. However, this architecture, which relies entirely on electrical signals to transmit steering intentions, also significantly increases the risk of system failure. Once the steer-by-wire system malfunctions, especially if the steering execution subsystem fails or communication between the road feel feedback subsystem and the execution subsystem is interrupted, the vehicle will lose its basic steering ability, seriously threatening driving safety. Therefore, existing solutions lack effective redundancy mechanisms for scenarios involving a complete failure of the steer-by-wire system, making it difficult to guarantee the steering safety and controllability of the entire vehicle under critical failures. Summary of the Invention

[0003] The present invention aims to solve the technical problems existing in the above-mentioned related technologies, and proposes a steer-by-wire failure handling method, device and vehicle based on distributed drive. When the steer-by-wire system completely fails, it can generate additional yaw torque by differentially distributing the four-wheel drive torque through the distributed drive system, thereby achieving effective alternative control of vehicle steering and ensuring driving safety.

[0004] The solution to the technical problem of this invention is as follows: This invention provides a method for handling steer-by-wire faults based on distributed drive, comprising the following steps: Obtain the fault status of the steer-by-wire system; When it is determined that the steer-by-wire system has completely failed and lost its steering ability, the distributed drive system is activated as the alternative execution unit for the steering function. The driver's steering intention is obtained, combined with the current vehicle speed, the target front wheel steering angle is calculated, and the corresponding target yaw rate is determined based on the vehicle dynamics model. Calculate the deviation between the vehicle's actual yaw rate and the target yaw rate; The additional yaw moment required for the entire vehicle is calculated based on the deviation, and the driving torque of each of the four wheels is distributed according to the additional yaw moment. The distributed drive system is controlled to independently adjust the output torque of each wheel-end motor according to the allocated drive torque, so as to generate the additional yaw torque, complete the driver's steering intention, and realize the vehicle steering control.

[0005] Furthermore, the driver's steering intention is obtained based on the steering wheel angle signal, specifically including: determining whether the steering wheel angle sensor inside the steer-by-wire system is valid; if valid, then using its output steering wheel angle signal; if invalid, then switching to a backup steering wheel angle sensor outside the steer-by-wire system to obtain the steering wheel angle signal.

[0006] Furthermore, the backup steering wheel angle sensor includes: a redundant angle sensor installed on the steering column, or an angle signal of the planned path of the autonomous driving system acquired via the CAN bus.

[0007] Furthermore, before enabling the distributed drive system, the following are also included: Determine whether the distributed driver system is in normal working condition; if the distributed driver system has a fault, then the fault degradation process is not executed.

[0008] Furthermore, the distributed drive system includes four independently controllable wheel-end motors, corresponding to the left front wheel, right front wheel, left rear wheel, and right rear wheel of the vehicle, respectively.

[0009] Furthermore, the additional yaw moment is achieved by differentially distributing the drive torque of the left and right wheels on the same axle, specifically including: Based on the vehicle's wheelbase, track width, and current speed, establish a mapping relationship between the additional yaw moment and the torque difference between the left and right wheels on the same axle; Based on the mapping relationship, calculate the target torque difference between the left front wheel and the right front wheel, and between the left rear wheel and the right rear wheel; Based on the basic driving force requirements of the vehicle during driving, the driving torque of each wheel is superimposed and distributed to create the target torque difference between the left and right wheels on the same axle, thereby generating the additional yaw torque.

[0010] Furthermore, the complete failure of the steer-by-wire system includes at least one of the following: a failure of the steering actuation subsystem, a communication interruption between the road feel feedback subsystem and the steering actuation subsystem, or a failure of the steering actuation motor.

[0011] On the other hand, this application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the aforementioned method for handling steer-by-wire faults based on distributed drive.

[0012] On the other hand, this application provides a vehicle including a steer-by-wire system, a distributed drive system, a yaw rate sensor, a vehicle speed sensor, and the aforementioned electronic equipment.

[0013] Furthermore, the steer-by-wire system includes an internal steering wheel angle sensor, and the vehicle is also equipped with a backup steering wheel angle sensor independent of the steer-by-wire system, which is used to provide a steering intention signal when the internal steering wheel angle sensor fails.

[0014] The beneficial effects of this invention are as follows: This application provides a method, device, and vehicle for handling steer-by-wire faults based on distributed drive. This method, in extreme fault scenarios where the steer-by-wire system completely fails and loses its steering execution capability, activates the distributed drive system as a redundant execution unit across systems. This converts the driver's steering intention into differential distribution of four-wheel drive torque, thereby generating the required additional yaw torque. This effectively replaces traditional mechanical or electronic steering functions, achieving active control of vehicle steering. This method not only significantly improves the functional safety and controllability of steer-by-wire vehicles when critical systems fail, but also fully utilizes the advantages of multi-actuator collaboration in the electric chassis, achieving highly reliable fault degradation processing and ensuring the safety of passengers. This application also provides corresponding devices and vehicles, the beneficial effects of which are the same as those of the method described above, and will not be repeated here.

[0015] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0016] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.

[0017] Figure 1 This is a flowchart of the steer-by-wire fault handling method based on distributed drive provided in this application; Figure 2 This is a structural diagram of the electronic device provided in this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] The present application will be further described below with reference to the accompanying drawings and specific embodiments. The described embodiments should not be considered as limitations on the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0020] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0022] With the accelerated advancement of the "new four modernizations" (electrification, intelligence, connectivity, and sharing) in the automotive industry, steer-by-wire (SbW) technology, as a core component of intelligent chassis, is gradually replacing traditional mechanical steering systems. By eliminating the mechanical connection between the steering wheel and steering actuators (such as the steering column and universal joints), steer-by-wire systems rely entirely on electrical signals to transmit the driver's steering intentions. This offers significant advantages such as simplified structure, flexible layout, programmable transmission ratios, and support for advanced autonomous driving. Especially in high-level intelligent driving scenarios, steer-by-wire can be deeply coupled with perception, decision-making, and control modules to achieve more precise and faster vehicle dynamic responses.

[0023] However, this "de-mechanization" design also brings new safety challenges: if key components in the steer-by-wire system (such as the steering actuator motor, angle sensor, and communication bus) fail, the vehicle may completely lose its steering ability, leading to a serious safety accident. Therefore, how to ensure that the vehicle still has basic steering control capabilities when the steer-by-wire system partially or completely fails has become a core issue in functional safety (compliant with ISO 26262 ASIL level requirements) design.

[0024] To address this challenge, the industry urgently needs to build a cross-system redundancy mechanism. This mechanism should be able to call upon other onboard subsystems (such as drive, braking, and suspension) to intervene collaboratively when the main steering system fails, achieving safe operation under fail-operational conditions. Currently, some technical solutions exist for emergency handling of steer-by-wire system failures. For example, when the road feel feedback subsystem (i.e., the steering wheel end) fails and the driver cannot input steering commands through the steering wheel, alternative devices such as the turn signal stalk, gear shift lever, or window control buttons can be used to obtain the driver's steering intention and transmit it to the steering execution subsystem, which is still functioning normally, thus continuing to control the front wheel steering. In addition, some research has attempted to use Electronic Stability Program (ESP) or braking systems to intervene in yaw moment to assist vehicle stability control, but these mainly focus on preventing dynamic instability scenarios such as sideslip, rather than serving as a complete replacement for the main steering function.

[0025] However, the aforementioned existing technologies have significant limitations: First, they are only applicable to specific scenarios where the road feel feedback subsystem fails, completely neglecting situations where the steering execution subsystem itself malfunctions (such as steering motor damage, steering gear jamming, or communication interruption), and such execution-level failures will directly lead to the vehicle completely losing its steering ability; second, existing solutions lack cross-system functional redundancy design, over-relying on internal components of the steer-by-wire system, and cannot meet the "fail-operational" requirements of high-level functional safety (such as ISO26262 ASIL D); third, they fail to effectively utilize the independent control capability of the distributed electric drive system over the four-wheel drive torque to generate yaw torque for steering substitution, missing the natural safety redundancy advantages brought by the electrified chassis; finally, steering intention acquisition usually relies on a single steering wheel angle sensor, lacking an effective fusion mechanism with external redundant sensors or autonomous driving planning modules, resulting in insufficient robustness and fault tolerance.

[0026] To address the aforementioned technical problems, this application proposes a steer-by-wire fault handling method, device, and vehicle based on distributed drive. Its main technical features are: when the steer-by-wire system (including the road feel feedback subsystem and / or steering execution subsystem) is determined to be completely ineffective and lose steering execution capability, a distributed drive system with four-wheel independent torque control capability is actively activated as a substitute execution unit for the steering function; by fusing steering wheel angle signals (supporting primary / backup sensor switching) with vehicle speed information, the target front wheel angle and corresponding target yaw rate are calculated, and based on the feedback deviation of the actual yaw rate, the required additional yaw torque is dynamically generated; this torque is then converted into a differential drive torque distribution command for the coaxial left and right wheels, and the distributed drive system precisely adjusts the output of the motors at each wheel end to generate a yaw effect in a pure drive mode, achieving effective response to the driver's steering intention and controllable adjustment of the vehicle direction, thereby constructing a cross-domain redundant safety mechanism that does not rely on traditional steering actuators.

[0027] First, the method for handling steer-by-wire faults based on distributed drive provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0028] Reference Figure 1 The implementation process of the steer-by-wire fault handling method based on distributed drive provided in this application embodiment includes, but is not limited to, the following steps.

[0029] Step S110: Obtain the fault status of the steer-by-wire system; when it is determined that the steer-by-wire system has completely failed and lost its steering execution capability, activate the distributed drive system as the alternative execution unit for the steering function.

[0030] In step S110, the current operating status of the steer-by-wire system is monitored and acquired in real time, especially to identify whether a fault exists. By collecting the working signals or fault flags of various modules within the system (such as the road feel feedback subsystem, the steering execution subsystem, and their communication links), it is determined whether an abnormality has occurred in the steer-by-wire system. This step is the prerequisite and triggering condition for the entire fault handling process. Only by accurately determining whether the system has failed and the degree of failure can it be determined whether subsequent degradation control strategies need to be initiated.

[0031] Once it is confirmed that the steer-by-wire system has completely lost its steering capability (e.g., steering motor failure, actuator jamming, or critical communication interruption), the distributed drive system is actively activated, allowing it to take over the vehicle direction control functions originally performed by the steering actuator. At this point, the distributed drive system is no longer solely used to drive the vehicle forward; it is given a new role—as a redundant actuator for steering functions, enabling cross-system functional takeover and ensuring that the vehicle retains basic steering capability even after the primary steering system fails.

[0032] Step S120: Obtain the driver's steering intention, combine it with the current vehicle speed, calculate the target front wheel steering angle, and determine the corresponding target yaw rate based on the vehicle dynamics model.

[0033] In step S120, the steering intention (usually via steering wheel angle signal) is extracted from the driver's operation and, combined with the current vehicle speed—a key vehicle state parameter—the required front wheel steering angle under normal steering conditions is derived. Subsequently, the vehicle dynamics model is used to map this front wheel steering angle to the target yaw rate the vehicle should achieve. This step establishes the theoretical relationship between driver input and the overall vehicle motion response, providing a target benchmark for subsequent simulation of steering effects using driving torque.

[0034] Step S130: Calculate the deviation between the vehicle's actual yaw rate and the target yaw rate.

[0035] In step S130, the vehicle's current actual yaw motion state is acquired through a yaw rate sensor and compared with the calculated target yaw rate to obtain the deviation value between the two. This deviation reflects the degree of deviation between the vehicle's actual trajectory and the driver's desired trajectory. It is a key basis for determining whether additional control intervention is needed and a direct input for subsequent calculations of the required compensation torque.

[0036] Step S140: Calculate the additional yaw moment required for the entire vehicle based on the deviation, and distribute the driving torque of each of the four wheels according to the additional yaw moment.

[0037] In step S140, the additional yaw moment required to correct the deviation is first calculated using a control algorithm (such as proportional-integral-derivative control or a more advanced vehicle stability controller) based on the yaw rate deviation. Then, based on vehicle structural parameters (such as track width and wheelbase) and the current driving state, this additional yaw moment is converted into a drive torque distribution scheme that should be output to each of the four wheels. This process realizes the transformation from macroscopic vehicle motion requirements to microscopic wheel-end execution commands and is the core calculation step for the drive system to achieve steering substitution function.

[0038] In step S150, the distributed drive system is controlled to independently adjust the output torque of each wheel-end motor according to the allocated drive torque to generate additional yaw torque, thereby fulfilling the driver's steering intention and realizing vehicle steering control.

[0039] In step S150, the generated four-wheel drive torque command is sent to the distributed drive system, where the output torque is independently and precisely adjusted by the motors at each wheel end. Through differential drive of the coaxial left and right wheels (e.g., acceleration of the left wheel and deceleration of the right wheel), the required additional yaw moment is generated on the vehicle, thereby changing the vehicle's heading and guiding it towards the driver's desired trajectory. This step ultimately achieves effective control of steering intentions and vehicle direction solely through the drive system, without the involvement of traditional steering actuators.

[0040] In some embodiments of this application, the driver's steering intention is obtained based on the steering wheel angle signal, specifically including: determining whether the steering wheel angle sensor inside the steer-by-wire system is valid; if valid, then using the steering wheel angle signal output by the sensor; if invalid, then switching to a backup steering wheel angle sensor outside the steer-by-wire system to obtain the steering wheel angle signal.

[0041] This design aims to ensure reliable and continuous acquisition of the driver's true steering intention under any fault scenario, thereby providing accurate input for subsequent fault degradation control. Since the steer-by-wire system eliminates mechanical connections, the steering wheel angle signal becomes the sole original basis for expressing the driver's steering needs, and its reliability directly determines the effectiveness of the entire redundant control strategy. Therefore, this application designs a primary / backup switching mechanism: firstly, the working status of the steering wheel angle sensor integrated within the steer-by-wire system is monitored in real time. If its signal is normal and fault-free, the high-precision, low-latency native signal is used preferentially; once the sensor failure is detected (such as signal loss, data anomaly, or hardware failure), the system immediately and seamlessly switches to a backup steering wheel angle sensor independent of the steer-by-wire system (e.g., a redundant sensor mounted on the steering column) to continue acquiring steering wheel angle information. This dual-source redundancy design not only improves the robustness of steering intention recognition but also avoids the risk of the entire fault degradation function being paralyzed due to a single sensor failure, making it a key safeguard for achieving high functional safety levels (such as ASIL D).

[0042] In some embodiments of this application, the backup steering wheel angle sensor includes: a redundant angle sensor mounted on the steering column, or an angle signal of the planned path of the autonomous driving system acquired via the CAN bus.

[0043] Specifically, the backup steering wheel angle sensor provides a multi-layered and heterogeneous source of redundancy for obtaining the driver's steering intentions, in order to address the signal availability issues under different failure scenarios, thereby further improving the system's functional continuity and safety under extreme failure conditions.

[0044] On the one hand, when the steering wheel angle sensor inside the steer-by-wire system fails, the redundant angle sensor installed on the mechanical steering column can serve as a physical backup, directly measuring the actual rotation angle of the steering wheel. Its advantage lies in its hardware isolation from the main sensor and its independent power supply and signal link. Even if the steer-by-wire electronic system is completely paralyzed, as long as the steering wheel still has a mechanical structure (such as a non-drive connection for safety redundancy), the sensor may still work normally.

[0045] On the other hand, in advanced intelligent driving scenarios, if the vehicle is in autonomous driving mode or has autonomous driving capabilities, the system can also obtain the planned path turning angle signal (i.e., the expected vehicle steering demand) from the autonomous driving decision module via the CAN bus, serving as an indirect substitute for the driver's intention. This system-level collaborative approach not only expands the diversity of steering intention sources but also enables the fault degradation strategy to be compatible with both manual and autonomous driving operating states, enhancing the flexibility and fault tolerance of the vehicle control architecture. By simultaneously supporting both hardware redundancy and functional redundancy as backup paths, this application significantly improves the possibility of maintaining basic steering control even in the event of main sensor failure or even a complete collapse of the steer-by-wire system.

[0046] In some embodiments of this application, before activating the distributed drive system, the method further includes determining whether the distributed drive system is in normal working order. If the distributed drive system malfunctions, fault degradation processing is not performed. This step ensures the safety and effectiveness of the fault degradation strategy itself, preventing the blind activation of redundant control when the primary system (steer-by-wire) fails and the backup execution system (distributed drive) also malfunctions, thereby avoiding further exacerbation of vehicle dynamic control loss or safety risks due to erroneous intervention.

[0047] Since the steering substitution function proposed in this application is highly dependent on the distributed drive system’s ability to precisely and independently control the torque of the four wheel-end motors, if the system itself malfunctions (e.g., a wheel motor fails, an inverter malfunctions, a communication interruption, or a power problem), it cannot reliably generate the required additional yaw torque, and may even output incorrect drive torque, causing the vehicle to yaw, sideslip, or other unstable behaviors.

[0048] Therefore, before deciding to activate the distributed drive system as the alternative execution unit for steering function, its health status must first be diagnosed and confirmed. Only when the distributed drive system is determined to be fully functional and able to respond normally to control commands is it allowed to intervene in steering control; conversely, if it has any fault affecting its yaw moment generation capability, the current fault degradation operation is proactively abandoned, and a more conservative safety strategy is adopted (such as prompting the driver to stop, limiting vehicle speed, or activating other braking-type stability controls). This pre-judgment mechanism reflects the "safety first" design principle and is a key link in achieving highly reliable and trustworthy fault-tolerant control.

[0049] In some embodiments of this application, the distributed drive system includes four independently controllable wheel-end motors, corresponding to the left front wheel, right front wheel, left rear wheel, and right rear wheel of the vehicle, respectively. By configuring a dedicated wheel-end motor (or wheel-side motor) for each wheel, the vehicle can individually adjust the output torque of the four wheels (left front, right front, left rear, and right rear) with millisecond-level precision. This is the physical basis for generating controllable additional yaw moment. In traditional centralized drive or single-axle drive vehicles, it is impossible to actively intervene in the vehicle's yaw motion through the differential driving force between the left and right wheels. However, the four-wheel independent drive structure adopted in this application allows for a precise torque difference between the left and right wheels on the same axle. This enables the generation of a yaw moment around the vehicle's center of gravity using the asymmetrical distribution of driving force without relying on the steering mechanism, thereby achieving effective control of the vehicle's heading. This hardware configuration is not only a prerequisite for the implementation of this fault degradation method but also determines the yaw moment amplitude, response speed, and control precision that the system can achieve. It is a key execution carrier supporting the cross-system redundancy concept of "using drive instead of steering".

[0050] In some embodiments of this application, the additional yaw moment is achieved by differentially distributing the drive torque of the left and right wheels on the same axle, specifically including the following steps.

[0051] Step S210: Based on the vehicle's wheelbase, track width, and current speed, establish a mapping relationship between the additional yaw moment and the torque difference between the left and right wheels on the same axle.

[0052] In step S210, a physically accurate and dynamically adaptive mathematical model is constructed to convert the required additional yaw moment into executable wheel torque control commands. Since the yaw moment is generated by the torque couple formed by the driving forces of the left and right wheels in the track direction, its magnitude depends not only on the torque difference between the left and right wheels but also on the vehicle's geometric parameters (such as track width) and the current driving state (such as vehicle speed affecting tire lateral force and overall vehicle response characteristics). Therefore, this step establishes a quantitative mapping relationship between the additional yaw moment and the required torque difference between the left and right wheels on the same axle (e.g., through vehicle dynamics equations or lookup table / gain scheduling methods) by introducing key parameters such as wheelbase, track width, and vehicle speed. This provides a theoretical basis for the subsequent precise allocation of wheel-end torque. This mapping relationship ensures that the system can reasonably calculate the minimum effective torque difference required to achieve the target yaw effect under different vehicle speeds and configurations, balancing control accuracy and energy efficiency.

[0053] Step S220: Calculate the target torque difference between the left front wheel and the right front wheel, and between the left rear wheel and the right rear wheel, based on the mapping relationship.

[0054] In step S220, the additional yaw moment requirement determined in the previous step is specifically decomposed into the torque differences that the front and rear axles need to generate. Since vehicles typically have two axles, front and rear, the yaw moment can be contributed by the front axle, the rear axle, or both. Therefore, the target torque differences between the left and right front wheels, and between the left and right rear wheels, need to be calculated separately. This decomposition process considers the different contribution weights of the front and rear axles to the yaw response (which may be affected by factors such as center of gravity position and load distribution), thereby achieving a more optimized torque distribution strategy. By clearly defining the torque differences between the left and right wheels on each axle, the system can selectively adjust the output of each wheel motor to ensure that the resulting torque accurately matches the required additional yaw moment, laying the foundation for stable and smooth steering substitution control.

[0055] In step S230, the driving torque of each wheel is superimposed and distributed based on the basic driving force requirements of the vehicle during driving, so that the left and right wheels on the same axle form a target torque difference to generate additional yaw torque.

[0056] In step S230, under the premise of meeting the vehicle's basic driving needs (such as the total driving force required for acceleration, constant speed, or hill climbing), the differential torque used to achieve yaw control is "superimposed" onto the basic driving torque of each wheel, thereby achieving coordinated control of driving and steering functions. Specifically, the system first determines the total driving force required for the vehicle to maintain its current driving state based on information such as accelerator pedal opening, vehicle speed, and slope, and then rationally distributes it to the four wheels as the basic torque. Subsequently, based on this, according to the target torque difference calculated in step S220, the torque of the left and right wheels is asymmetrically adjusted (for example, adding ΔT to the left wheel and subtracting ΔT from the right wheel on the basic torque), so that the total output satisfies both the longitudinal driving requirements and forms the required yaw torque. This superposition and distribution mechanism ensures that the vehicle can maintain normal driving performance and driving stability while performing fault-degraded steering control, avoiding sacrificing the vehicle's basic operating capabilities for the sake of simply pursuing yaw effect, and reflecting the design concept of multi-objective coordinated control.

[0057] In some embodiments of this application, a complete failure of the steer-by-wire system includes at least one of the following: a failure of the steering actuation subsystem, a communication interruption between the road feel feedback subsystem and the steering actuation subsystem, or a failure of the steering actuation motor.

[0058] Because the steer-by-wire system consists of two core components—a road feel feedback subsystem (responsible for collecting steering wheel angle and simulating road feel) and a steering execution subsystem (responsible for driving the front wheels to steer)—and the two work together through electrical signals rather than mechanical connections, its failure modes are diverse.

[0059] This application defines "complete failure" as several typical high-risk fault scenarios that cause a vehicle to lose its actual steering capability: First, a complete failure of the steering execution subsystem, such as controller damage or software crash, rendering it unable to respond to any steering commands; second, an interruption of communication between the road feel feedback subsystem and the steering execution subsystem, so that even if the driver turns the steering wheel normally, their intention cannot be transmitted to the execution end, causing a break in the control link; third, failure of the steering execution motor. As the power source that directly drives the steering mechanism, once the motor burns out, jams, or has an abnormal power supply, even if the control signal is normal, the front wheels cannot turn. Any of the above situations will prevent the vehicle from steering in the traditional way, posing a serious functional safety risk. By clearly listing these specific failure modes, this application not only enhances the accuracy and coverage of fault identification but also ensures that the distributed drive redundancy mechanism is activated only when truly needed, avoiding false triggering or missed triggering, thereby improving the reliability, specificity, and engineering feasibility of the entire fault handling system.

[0060] Secondly, refer to Figure 2This application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the aforementioned method for handling steer-by-wire faults based on distributed drive.

[0061] Furthermore, embodiments of this application provide a vehicle, including a steer-by-wire system, a distributed drive system, a yaw rate sensor, a vehicle speed sensor, and the aforementioned electronic equipment.

[0062] The steer-by-wire system is the core execution unit for achieving vehicle steering, responsible for receiving the driver's steering intentions input through the steering wheel and translating them into actual steering actions of the front wheels. In this application, the steer-by-wire system eliminates traditional mechanical connections, relying entirely on electrical signals to transmit control commands, and includes a road feel feedback subsystem and a steering execution subsystem. It integrates a steering wheel angle sensor to collect the driver's steering operation signals in real time. When the system is working normally, it dominates vehicle steering; in the event of a complete failure, a fault degradation mechanism is triggered, and the distributed drive system takes over the steering control function.

[0063] The distributed drive system consists of four independently controllable wheel-end motors, corresponding to the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively, and has the ability to precisely adjust the driving torque of each wheel at the millisecond level. In this application, it not only undertakes conventional drive tasks, but its more crucial role is to act as a redundant execution unit across the system when the steering-by-wire system completely fails. It generates additional yaw torque by differentially distributing the driving torque of the left and right wheels on the same axle, thereby achieving active intervention in the vehicle's heading and alternative execution of steering intentions, ensuring driving safety.

[0064] The yaw rate sensor is used to measure the actual yaw rate of the vehicle's rotation about its vertical axis (Z-axis) in real time, and is a key sensing unit for feedback on the vehicle's dynamic response status. In the fault degradation control logic of this application, the measured yaw rate provided by the sensor is compared with the target yaw rate calculated based on the driver's intention. The resulting deviation is used as the basis for calculating the required additional yaw torque, thereby forming a closed-loop control to ensure that the actual trajectory of the vehicle is as close as possible to the driver's expectation.

[0065] Vehicle speed sensors are used to obtain the vehicle's current speed, which is a core state parameter affecting steering dynamics. In this application, vehicle speed information is used in several key aspects: first, it is used to calculate the target front wheel steering angle and target yaw rate in conjunction with the steering wheel angle (because the vehicle's steering response characteristics differ at different speeds); second, it serves as the basis for dynamic gain adjustment when establishing the mapping relationship between the additional yaw moment and the wheel torque difference. The accurate acquisition of vehicle speed directly determines the adaptability and stability of the fault degradation control strategy.

[0066] The aforementioned electronic device includes a memory and a processor, storing a computer program that implements the steer-by-wire fault handling method described in this application. When the processor executes the program, it can coordinate various sensors and execution systems to complete the entire process of control logic, including fault diagnosis, intent recognition, yaw moment calculation, and four-wheel torque distribution. As the operating platform for the vehicle control algorithm, this electronic device is the core hub connecting the perception, decision-making, and execution layers, ensuring that the fault degradation strategy is implemented efficiently and reliably while meeting functional safety requirements.

[0067] In some embodiments of this application, the steer-by-wire system includes an internal steering wheel angle sensor, and the vehicle is also provided with a backup steering wheel angle sensor independent of the steer-by-wire system, which is used to provide a steering intention signal when the internal steering wheel angle sensor fails.

[0068] The internal steering wheel angle sensor is integrated into the steer-by-wire system to collect the steering wheel's rotation angle and direction in real time, serving as the primary source of the driver's original steering intention. Under normal system operation, its output signal is directly used to calculate the target front wheel steering angle. Its high precision and low latency provide a superior driving experience for steer-by-wire; however, as it is part of the main system, it may fail simultaneously in the event of a system failure, thus requiring redundant backup.

[0069] The backup steering wheel angle sensor is set independently of the steer-by-wire system (e.g., mounted on the steering column). In the event of failure of the internal steering wheel angle sensor or communication interruption in the steer-by-wire system, it continues to provide steering wheel angle information as a redundant signal source. Its physically isolated design ensures that even if the main system completely fails, the driver's steering intention can still be reliably acquired. This is a key guarantee for achieving high availability fault degradation control, significantly improving the overall robustness and functional safety level of the system.

[0070] In summary, the steer-by-wire fault handling method, device, and vehicle based on distributed drive provided in this application have the following technical effects.

[0071] This application's technical solution enables effective alternative control of vehicle steering when the online steering system completely fails (e.g., steering execution subsystem failure, communication interruption, or execution motor failure). This is achieved by activating a distributed drive system as a redundant execution unit across systems. The solution utilizes four independently controllable wheel-end motors to calculate the target yaw rate based on the driver's steering intention and vehicle speed. Combining this with the measured yaw rate deviation, it dynamically generates an additional yaw torque, which is then differentially distributed to the left and right wheels on the same axle to actively intervene in the vehicle's heading. This mechanism overcomes the limitations of traditional methods that rely solely on redundancy within the steering system, constructing a heterogeneous safety architecture that deeply integrates drive and steering, significantly improving the vehicle's controllability and functional safety level in high-risk failure scenarios.

[0072] Meanwhile, this application ensures the continuity and reliability of steering intention acquisition by setting up primary and backup dual-path steering wheel angle signal sources (including sensors inside the steer-by-wire system and independent backup sensors); and through a closed-loop control strategy, it accurately superimposes differential torque while meeting the vehicle's basic drive requirements, taking into account both longitudinal driving performance and lateral stability. The sensors and actuators used are typical configurations of current electrified intelligent chassis, with clear control logic, well-defined diagnostic conditions, and strong engineering feasibility, providing a practical and feasible fault degradation solution for the safe application of steer-by-wire technology in high-level intelligent electric vehicles.

[0073] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this application are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and sub-operations described as part of a larger operation are executed independently.

[0074] Furthermore, although this application is described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding this application. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of ordinary skill of an engineer. Therefore, those skilled in the art can implement the application set forth in the claims using ordinary skill. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of this application, which is determined by the full scope of the appended claims and their equivalents.

[0075] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part 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 programs 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, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0076] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequential list of executable programs for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, a program execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can retrieve and execute a program from or in conjunction with such a program execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can mean any means that can contain, store, communicate, propagate, or transmit a program for use by or in conjunction with a program execution system, apparatus, or device.

[0077] More specific examples (a non-exhaustive list) of computer-readable media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Additionally, computer-readable media can even be paper or other suitable media on which programs can be printed, for example, by optically scanning the paper or other media, then editing, interpreting, or, if necessary, processing it in a suitable manner to obtain the program electronically, and then storing it in computer memory.

[0078] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable program execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0079] In the foregoing description of this specification, the reference to terms such as "one embodiment / implementation," "another embodiment / implementation," or "certain embodiments / implementations," etc., indicates that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in an embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0080] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0081] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A method for handling a failure of a steer-by-wire system based on distributed drive, characterized in that, The method comprises the following steps: acquiring a failure state of a steer-by-wire system; when it is determined that the steer-by-wire system is completely failed and loses steering execution capability, enabling a distributed drive system as a substitute execution unit of a steering function; acquiring a steering intention of a driver, combining the steering intention with a current vehicle speed, calculating a target front wheel steering angle, and determining a corresponding target yaw rate based on a vehicle dynamics model; calculating a deviation between an actual yaw rate of the vehicle and the target yaw rate; calculating an additional yaw moment required by the whole vehicle based on the deviation, and distributing driving torques of four wheels according to the additional yaw moment; controlling the distributed drive system to independently adjust output torques of the wheels of the distributed drive system according to the distributed driving torques, so as to generate the additional yaw moment, complete the steering intention of the driver, and realize steering control of the vehicle.

2. The distributed drive based steer-by-wire failure handling method of claim 1, wherein, The steering intention of the driver is obtained based on a steering wheel angle signal, and specifically comprises: determining whether a steering wheel angle sensor inside the steer-by-wire system is valid; if valid, using the output steering wheel angle signal; if invalid, switching to a backup steering wheel angle sensor outside the steer-by-wire system to obtain the steering wheel angle signal.

3. The distributed drive based steer-by-wire failure handling method of claim 1, wherein, The backup steering wheel angle sensor comprises: a redundant steering angle sensor mounted on a steering column, or an automatic driving system planned path steering angle signal obtained through a CAN bus.

4. The distributed drive based steer-by-wire failure handling method of claim 1, wherein, Before the distributed drive system is enabled, the method further comprises: determining whether the distributed drive system is in a normal working state; if the distributed drive system has a fault, the failure degradation processing is not performed.

5. The distributed drive based steer-by-wire failure handling method of claim 1, wherein, The distributed drive system comprises four independently controllable wheel end motors corresponding to a front left wheel, a front right wheel, a rear left wheel and a rear right wheel of the vehicle.

6. The distributed drive based steer-by-wire failure handling method of claim 1, wherein, The additional yaw moment is realized by differentially distributing driving torques of coaxial left and right wheels, and specifically comprises: establishing a mapping relationship between the additional yaw moment and a torque difference of the coaxial left and right wheels based on a wheelbase, a track and a current vehicle speed of the vehicle; calculating target torque differences of the front left wheel and the front right wheel and the rear left wheel and the rear right wheel according to the mapping relationship; superimposing and distributing driving torques of the wheels to make the coaxial left and right wheels form the target torque differences, so as to generate the additional yaw moment, in combination with a basic driving force demand of the vehicle during driving.

7. The distributed drive based steer-by-wire failure handling method of claim 1, wherein, The complete failure of the steer-by-wire system comprises at least one of a steering execution subsystem failure, a communication interruption between a road feeling feedback subsystem and the steering execution subsystem, or a steering execution motor failure.

8. An electronic device, comprising: The electronic device comprises a memory and a processor, the memory stores a computer program, and the processor implements the failure processing method of the steer-by-wire system based on the distributed drive when executing the computer program.

9. A vehicle characterized by comprising: The electronic device comprises a steer-by-wire system, a distributed drive system, a yaw rate sensor, a vehicle speed sensor and the electronic device of claim 8.

10. The vehicle of claim 9, wherein, The steer-by-wire system comprises an internal steering wheel angle sensor, and the vehicle is further provided with a backup steering wheel angle sensor independent of the steer-by-wire system, for providing a steering intention signal when the internal steering wheel angle sensor is failed.

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