Safety control method, system and device for vehicle steer-by-wire system

Abstract

This application discloses a safety control method, system, and device for a vehicle steer-by-wire system, relating to the field of automotive steering control technology. The method includes: when a preset fault event occurs in the main control path of the steer-by-wire system, acquiring the current vehicle speed, the current steering wheel speed, and the target control torque of the main control path before the fault event; determining a torque handover duration based on the current vehicle speed and the current steering wheel speed; acquiring a first control weight of the main control path and a second control weight of the backup control path within the torque handover duration; wherein the first control weight monotonically decreases with the torque handover duration, the second control weight monotonically increases with the torque handover duration, and the sum of the first and second control weights is always equal to 1; and controlling the main control path and the backup control path to perform torque output operations within the torque handover duration based on the target control torque, the first control weight, and the second control weight.

Description

Technical Field

[0001] This application relates to the field of automotive steering control technology, and in particular to a safety control method, system, device and storage medium for a vehicle steer-by-wire system. Background Technology

[0002] steer-by-wire systems eliminate the mechanical connection between the steering wheel and the steering actuator, transmitting steering commands entirely through electronic signals. This elimination of the mechanical connection presents new safety challenges; if the electronic system malfunctions, the vehicle may lose its steering ability. Therefore, steer-by-wire systems must possess fail-safe capability at Automotive Safety Integrity Level D, meaning they can maintain steering function even after a single failure.

[0003] Existing steer-by-wire systems generally employ a primary / backup redundancy architecture. Under normal operating conditions, steering control is performed by the primary control path, and when the primary control path fails, it switches to the backup control path. However, existing switching schemes often use a sequential logic of "first disconnecting the faulty path, then starting the backup path," meaning that the output of the primary control path is completely cut off first, and then the backup control path establishes its output from scratch. During the handover process between the primary and backup paths, this switching method results in a significant gap or interruption in output torque, causing unexpected fluctuations in vehicle steering action. The driver can clearly perceive these abnormal changes in steering torque, affecting driving smoothness. Summary of the Invention

[0004] The embodiments of this application provide a safety control method, system and device for a vehicle steer-by-wire system. When a preset fault event occurs in the main control path, the main control path and the backup control path synchronously perform torque output operation during the torque handover period, so that the wheel-end steering actuator maintains the continuity of torque output during the control switch.

[0005] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] This application specifically includes the following aspects: In a first aspect, this application proposes a safety control method for a vehicle steer-by-wire system, the vehicle steer-by-wire system including a main control path and a backup control path, the method comprising: In the event of a preset fault event in the main control path, the current vehicle speed, the current steering wheel speed, and the target control torque of the main control path before the fault event occurred are obtained; wherein, the preset fault event includes communication loss, logical operation abnormality, or shadow verification deviation; The torque handover duration is determined based on the current vehicle speed and the current steering wheel speed. Obtain the first control weight of the main control path and the second control weight of the backup control path within the torque handover time; wherein, the first control weight decreases monotonically with the torque handover time, the second control weight increases monotonically with the torque handover time, and the sum of the first control weight and the second control weight is always equal to 1; Based on the target control torque, the first control weight, and the second control weight, the main control path and the backup control path are controlled to perform torque output operations during the torque handover period.

[0007] In one feasible implementation, obtaining the first control weight of the main control path and the second control weight of the backup control path within the torque handover duration includes: Based on the torque handover duration, the start time of the torque handover duration, and the current time, determine the progress ratio within the torque handover duration at the current time; Based on the progress ratio, the first control weight and the second control weight corresponding to each moment within the torque handover duration are determined, wherein at the beginning of the torque handover duration, the first control weight is 1 and the second control weight is 0, and at the end of the torque handover duration, the first control weight is 0 and the second control weight is 1.

[0008] In one feasible implementation, determining the torque handover duration based on the current vehicle speed and the current steering wheel rotation speed includes: When the current vehicle speed is greater than the first preset vehicle speed and the current steering wheel speed is greater than the first preset speed, the torque transfer duration is determined to be the first preset duration. When the current vehicle speed is less than the second preset vehicle speed and the current steering wheel rotation speed is less than the second preset rotation speed, the torque transfer duration is determined as the second preset duration; wherein, the first preset vehicle speed is greater than the second preset vehicle speed, and the second preset duration is greater than the first preset duration.

[0009] In one feasible implementation, controlling the main control path and the backup control path to perform torque output operations during the torque handover period based on the target control torque, the first control weight, and the second control weight includes: Based on the target control torque and the first control weight, the target output torque of the main control path at each moment within the torque handover duration is determined; Based on the target control torque and the second control weight, the target output torque of the backup control path is determined at each moment within the torque handover duration; The main control path is controlled to perform torque output operation according to the target output torque at each moment within the torque transition period, and the backup control path is controlled to perform torque output operation according to the target output torque at each moment within the torque transition period.

[0010] In one feasible implementation, it further includes: The system acquires a first angle measurement value, a second angle measurement value, and a third angle measurement value from the wheel-end steering actuator in the vehicle steer-by-wire system; wherein, the first angle measurement value is used to characterize the measured steering angle; the second angle measurement value is used to characterize the steering angle determined based on the vehicle motor rotor position; and the third angle measurement value is used to characterize the steering angle determined based on the cross-axis current feedback value, the motor torque constant, the friction parameters, and the inertia parameters of the vehicle steer-by-wire system. Based on the first angle measurement value, the second angle measurement value, and the third angle measurement value, the target steering angle of the wheel-end steering actuator is determined.

[0011] In one feasible implementation, determining the target steering angle of the wheel-end steering actuator based on the first angle measurement value, the second angle measurement value, and the third angle measurement value includes: Obtain a first difference between the first angle measurement value and the second angle measurement value, a second difference between the first angle measurement value and the third angle measurement value, and a third difference between the second angle measurement value and the third angle measurement value; If the first difference, the second difference, and the third difference are all less than or equal to a preset deviation threshold, the first angle measurement value is determined as the target steering angle. If the first difference is greater than the preset deviation threshold and the second difference is greater than the preset deviation threshold, the target steering angle is determined based on the second angle measurement value and the third angle measurement value.

[0012] In one feasible implementation, it further includes: Based on the operating status parameters of the vehicle steer-by-wire system, the power-on initialization state of the vehicle steer-by-wire system is determined; When the power-on initialization state is incomplete, obtain the obstacle distance information of the environment in which the vehicle's steer-by-wire system is located; Based on the obstacle distance information, the wheel-end steering actuator is controlled to output a trial torque; During the process of the wheel-end steering actuator outputting the test torque, the first current change rate of the wheel-end steering actuator is obtained; When the rate of change of the first current is greater than the preset rate of change, the steering actuator at the wheel end is controlled to move in the opposite direction by a preset retraction angle. After the wheel-end steering actuator moves in the opposite direction by a preset retraction angle, the wheel-end steering actuator is controlled to move back to the original direction at a preset speed, and the second current change rate during the second movement of the wheel-end steering actuator is obtained. If the second current change rate is greater than the preset change rate, the current movement position is recorded as a temporary mechanical limit position, and the movement range of the wheel-end steering actuator is limited based on the temporary mechanical limit position.

[0013] In one feasible implementation, it further includes: Obtain the target current command value and the actual current feedback value of the tactile feedback actuator of the vehicle's steer-by-wire system; If the current deviation between the target current command value and the actual current feedback value is greater than the preset current deviation within a preset time, it is determined that the tactile feedback actuator has failed. If a failure event is determined in the tactile feedback actuator, the current vehicle speed is obtained, and the target damping torque value is determined based on the current vehicle speed; Based on the target damping torque value, the hysteresis damper of the vehicle's steer-by-wire system is controlled to apply a damping torque to the vehicle's steering wheel.

[0014] Secondly, this application also proposes a safety control system for a vehicle steer-by-wire system, comprising: The data acquisition module is used to acquire the current vehicle speed, the current steering wheel speed, and the target control torque of the main control channel before the occurrence of the fault event when a preset fault event occurs in the main control channel; wherein, the preset fault event includes communication loss, logical operation abnormality, or shadow verification deviation. The handover duration determination module is used to determine the torque handover duration based on the current vehicle speed and the current steering wheel speed; The control weight acquisition module is used to acquire the first control weight of the main control path and the second control weight of the backup control path within the torque handover time; wherein, the first control weight decreases monotonically with the torque handover time, the second control weight increases monotonically with the torque handover time, and the sum of the first control weight and the second control weight is always equal to 1. The smooth switching execution module controls the main control path and the backup control path to perform torque output operations within the torque handover period, based on the target control torque, the first control weight, and the second control weight.

[0015] Thirdly, this application also proposes an electronic device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program stored in the memory to implement the steps of the safety control method for the vehicle steer-by-wire system as described in any of the first aspects above.

[0016] This application proposes a safety control method for a vehicle steer-by-wire system. When a preset fault event occurs, the current vehicle speed and steering wheel speed are acquired, enabling the steer-by-wire system to perceive the vehicle's dynamic operating state. Simultaneously, the target control torque before the fault occurs is acquired as the reference command for subsequent torque output, ensuring consistency of driver needs before and after the switch. The torque handover duration is determined based on vehicle speed and steering wheel speed, allowing the handover duration to adaptively adjust according to actual operating conditions. A shorter duration is used under high-dynamic conditions to meet safety response requirements, while a longer duration is used under stable conditions to improve smoothness. Within the torque handover duration, a first control weight and a second control weight are acquired, with the first control weight monotonically decreasing and the second control weight monotonically increasing, and their sum always equal to 1. This ensures that the sum of the output torques of the two control paths always equals the target control torque at any given time. The main path gradually exits while the backup path gradually engages, guaranteeing continuous and uninterrupted total output torque. Ultimately, based on the target control torque and the two weighted control paths, the torque output is executed synchronously, ensuring that the torque remains continuous during the switching process. This completely eliminates the torque interruption problem in traditional solutions, enabling seamless switching without the driver's awareness, and improving the safety and smoothness of the steer-by-wire system.

[0017] This application discloses a safety control method, system, and device for a vehicle steer-by-wire system. Other advantages, objectives, and features of this application will be partly apparent from the following description and partly understood by those skilled in the art through study and practice of this application. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit this specification. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A flowchart illustrating a safety control method for a vehicle steer-by-wire system provided in this application embodiment; Figure 2 A functional module diagram of a safety control system for a vehicle steer-by-wire system provided in this application embodiment; Figure 3 This is a schematic diagram of the structure of a vehicle steer-by-wire control device provided in an embodiment of this application. Detailed Implementation

[0019] To better understand the technical solutions provided in the embodiments of this specification, the technical solutions of the embodiments of this specification will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this specification and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. In the absence of conflict, the embodiments of this specification and the technical features in the embodiments can be combined with each other.

[0020] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. The term "two or more" includes two or more cases.

[0021] This application provides a safety control method for a vehicle steer-by-wire system, wherein the vehicle steer-by-wire system includes a main control path and a backup control path. Please refer to... Figure 1 This is a flowchart illustrating a safety control method for a vehicle steer-by-wire system provided in an embodiment of this application, which may specifically include: S110. In the event of a preset fault event in the main control path, obtain the current vehicle speed, the current steering wheel speed, and the target control torque of the main control path before the fault event occurred; wherein the preset fault events include communication loss, logical operation abnormality, or shadow verification deviation.

[0022] For example, a vehicle's steer-by-wire (SbW) system eliminates the mechanical connection between the steering wheel and the steering actuator. To achieve fail-operational capability at Automotive Safety Integrity Level D (ASIL D), the steer-by-wire system employs a primary-backup redundancy architecture. The primary control path (i.e., the Master Microcontroller Unit, Master MCU) integrates a high-frequency self-diagnostic mechanism. When certain conditions are met, the primary control path actively declares its own failure. These preset fault events include: communication loss (such as interruption of the synchronization bus heartbeat message), logical operation anomalies (such as program flow infinite loops or deadlocks), and shadow verification deviations (such as the deviation between the target torque output by the primary control path and the theoretical torque independently calculated by the backup control path exceeding a threshold). When any of the above preset fault events occurs, the steer-by-wire system determines that control needs to be switched from the primary control path to the backup control path. At this point, the steer-by-wire system acquires the current vehicle speed and the current steering wheel speed, and latches the last valid target torque command output by the main control path before the fault occurred as the target control torque (i.e., the target torque). The target control torque is the steering torque command required by the driver before the handover and will be used as a constant reference value during subsequent handover processes.

[0023] S120: Determine the torque handover duration based on the current vehicle speed and the current steering wheel speed.

[0024] In some examples, the torque handover duration is determined based on the current vehicle speed and the current steering wheel rotation speed, including: When the current vehicle speed is greater than the first preset vehicle speed and the current steering wheel speed is greater than the first preset speed, the torque transfer time is determined to be the first preset time. When the current vehicle speed is less than the second preset vehicle speed and the current steering wheel speed is less than the second preset speed, the torque transfer time is determined to be the second preset time; wherein, the first preset vehicle speed is greater than the second preset vehicle speed and the second preset time is greater than the first preset time.

[0025] For example, torque transfer duration (i.e., current overlap time window) The torque transfer time (ω) is not a fixed constant, but rather dynamically and adaptively calculated based on the current vehicle speed (v) and the current steering wheel speed (ω). When the vehicle is traveling at high speed (e.g., speed greater than 100 km / h) or in emergency situations where the driver makes a sudden turn (e.g., steering wheel speed greater than 500 deg / s), the steer-by-wire system shifts towards higher safety response, setting the torque transfer time to a shorter first preset duration (e.g., 10ms to 12ms) to ensure that the Fault Tolerant Time Interval (FTTI) does not exceed the limit. When the vehicle is traveling at low speed (e.g., speed less than 20 km / h) and the steering wheel speed is low (e.g., less than 60 deg / s) during parking or low-speed situations, the steer-by-wire system shifts towards higher driving comfort, setting the torque transfer time to a longer second preset duration (e.g., 18ms to 20ms) to achieve a smoother transfer experience.

[0026] S130. Obtain the first control weight of the main control path and the second control weight of the backup control path within the torque handover time; wherein, the first control weight decreases monotonically with the torque handover time, the second control weight increases monotonically with the torque handover time, and the sum of the first control weight and the second control weight is always equal to 1.

[0027] For example, during the torque handover period, the output torque of the main control path and the backup control path is distributed according to a preset distribution rule. First control weight. The current fade-out coefficient corresponding to the main control path monotonically decreases from 1 at the start of the torque handover duration to 0 at the end; the second control weight The current fade-in coefficient corresponding to the backup control path monotonically increases from 0 at the start of the torque handover duration to 1 at the end. The sum of the two control weights is always equal to 1 (i.e., ...). + =1), ensuring that the sum of the output torques of the two paths is always equal to the total torque required by the driver.

[0028] In some examples, the first control weight of the main control path and the second control weight of the backup control path are obtained during the torque handover period, including: Based on the torque handover duration, the start time of the torque handover duration, and the current time, determine the progress ratio at the current time within the torque handover duration; Based on the progress ratio, the first control weight and the second control weight corresponding to each moment within the torque handover duration are determined. At the beginning of the torque handover duration, the first control weight is 1 and the second control weight is 0. At the end of the torque handover duration, the first control weight is 0 and the second control weight is 1.

[0029] For example, let the start time of the torque transfer duration be... If the torque transfer time is T and the current time is t, then the progress ratio is... The progress ratio The value range is from 0 to 1, where =0 indicates that the handover has just begun. =1 indicates that the handover has been completed.

[0030] The first control weight and the second control weight change with the progress ratio according to a preset cubic polynomial S-curve function relationship. , The S-curve function relationship is configured as follows: at the progress ratio When =0, the first control weight =1, Second Control Weight =0; in the progress ratio When =1, the first control weight =0, Second Control Weight =1; and in =0 and At point =1, the rate of change (first derivative) of both the first and second control weights is 0. This S-curve characteristic ensures that the rate of change of the weights at the start and end points of the transition is zero, thus achieving "zero-impact start" and "zero-impact landing".

[0031] S140. Based on the target control torque, the first control weight, and the second control weight, control the main control path and the backup control path to perform torque output operation during the torque handover time.

[0032] In some examples, based on the target control torque, a first control weight, and a second control weight, the main control path and the backup control path are controlled to perform torque output operations during the torque handover period, including: Based on the target control torque and the first control weight, the target output torque of the main control path is determined at each moment within the torque handover time. Based on the target control torque and the second control weight, the target output torque of the backup control path is determined at each moment within the torque handover time. The main control path is controlled to perform torque output operation according to the target output torque at each moment within the torque handover time, and the backup control path is controlled to perform torque output operation according to the target output torque at each moment within the torque handover time.

[0033] For example, at any moment within the torque handover period, the instantaneous output torque of the main control path is equal to the target control torque multiplied by the first control weight at that moment (i.e., The instantaneous output torque of the backup control path is equal to the target control torque multiplied by the second control weight at that moment (i.e., The instantaneous output torques of the two paths are superimposed at the RoadWheel Actuator (RWA) at the wheel end, resulting in a total torque. Always equal to the target control torque (i.e. = Throughout the entire torque handover period, the total torque remains constant; only the internal contributors smoothly switch from the main control path to the backup control path, ultimately driving the wheel-end steering actuators to operate according to the target control torque.

[0034] In some examples, it also includes: Acquire the first angle measurement value, the second angle measurement value, and the third angle measurement value of the wheel-end steering actuator in the vehicle steer-by-wire system; wherein, the first angle measurement value is used to characterize the measured steering angle; the second angle measurement value is used to characterize the steering angle determined based on the position of the vehicle motor rotor; and the third angle measurement value is used to characterize the steering angle determined based on the cross-axis current feedback value, the motor torque constant, the friction parameters and inertia parameters of the vehicle steer-by-wire system; Based on the first angle measurement value, the second angle measurement value, and the third angle measurement value, the target steering angle of the wheel-end steering actuator is determined.

[0035] For example, the first angle measurement is obtained directly by a Torque and Angle Sensor (TAS). Mounted at the steering wheel end, the TAS simultaneously measures the steering torque applied by the driver and the steering wheel angle, providing a direct absolute angle value. The second angle measurement is determined by a Rotor Position Sensor (RPS). Installed inside the motor of the steering actuator at the wheel end, the RPS detects the rotation angle of the motor rotor and calculates it as the wheel-end steering angle by combining it with the gear ratio. The third angle measurement is a dynamic calculation based on the motor current. Specifically, the output torque of the permanent magnet synchronous motor... With cross-axis current There is a linear relationship between them: ,in This represents the motor torque constant. The steer-by-wire system collects the three-phase current of the motor and extracts the quadrature-axis current. Combined with the motor torque constant The output torque of the permanent magnet synchronous motor is calculated, and then the rack resultant force is decoupled and calculated by combining the friction and inertia parameters of the steer-by-wire system to determine the actual force value on the rack. Finally, the third angle measurement value is determined based on the mapping relationship between the rack force value and the steering angle. By introducing three heterogeneous angle measurement sources based on different physical principles (direct measurement, rotor position estimation, and current dynamics estimation), heterogeneous redundancy of angle measurement is achieved. The three measurement sources have different failure modes and will not fail simultaneously due to the same cause (i.e., "common cause failure"), thereby improving the system's diagnostic coverage (DC) to the ASIL D level requirement.

[0036] In some examples, the target steering angle of the wheel-end steering actuator is determined based on a first angle measurement, a second angle measurement, and a third angle measurement, including: Obtain the first difference between the first angle measurement value and the second angle measurement value, the second difference between the first angle measurement value and the third angle measurement value, and the third difference between the second angle measurement value and the third angle measurement value; If the first difference, the second difference, and the third difference are all less than or equal to the preset deviation threshold, the first angle measurement value is determined as the target steering angle. If the first difference is greater than a preset deviation threshold and the second difference is greater than a preset deviation threshold, the target steering angle is determined based on the second angle measurement value and the third angle measurement value.

[0037] For example, firstly, the three angle measurements are compared pairwise to calculate their respective deviations. Then, when the first, second, and third differences are all less than or equal to a preset deviation threshold, i.e., under normal operating conditions where the three angle measurements are consistent (the deviations are all within the allowable range), the steer-by-wire system uses the first angle measurement (the direct measurement value of the torque angle sensor TAS) as the standard, while the second angle measurement (rotor position sensor RPS) continuously calibrates the zero position.

[0038] If both the first and second differences exceed the preset deviation thresholds, i.e., when the deviations between the first and second angle measurements, and between the first and third angle measurements, exceed the preset deviation thresholds, the torque angle sensor (TAS) is deemed to have malfunctioned (e.g., signal jump or loss). At this point, the steer-by-wire system compares the second angle measurement (calculated by the rotor position sensor (RPS)) with the third angle measurement (calculated by electrodynamics). Since they are based on completely different physical principles (electromagnetic induction and current-mechanical mapping), they have different failure modes. If their trends are consistent, the rotor position sensor (RPS) signal is deemed reliable, and the steer-by-wire system switches to angle control supported by both the second and third angle measurements, ignoring the damaged torque angle sensor (TAS).

[0039] In some examples, it also includes: Based on the operating status parameters of the vehicle steer-by-wire system, determine the power-on initialization state of the vehicle steer-by-wire system. When the power-on initialization state is incomplete, obtain the obstacle distance information of the environment in which the vehicle's steer-by-wire system is located; Based on the obstacle distance information, control the wheel-end steering actuator to output a trial torque; During the process of the wheel-end steering actuator outputting the test torque, the first current change rate of the wheel-end steering actuator is obtained; If the first current change rate is greater than the preset change rate, control the wheel-end steering actuator to move in the opposite direction by a preset retraction angle; After the wheel-end steering actuator moves in the opposite direction by a preset retraction angle, the wheel-end steering actuator is controlled to move back in the original direction at a preset speed, and the second current change rate during the second movement of the wheel-end steering actuator is obtained. If the second current change rate is greater than the preset change rate, the current movement position is recorded as a temporary mechanical limit position, and the movement range of the wheel-end steering actuator is limited based on the temporary mechanical limit position.

[0040] For example, after the vehicle is powered on, the steer-by-wire system first determines whether it has completed angle synchronization initialization, that is, it determines the power-on initialization status based on operating status parameters (such as the steer-by-wire system power-on flag, initialization completion flag, etc.). If the power-on initialization status is incomplete, the steer-by-wire system initiates the collision perception angle synchronization process: first, it uses the vehicle's surround-view camera or ultrasonic radar to sense whether there are obstacles and their distance to the front wheels. These obstacles and their distance constitute the obstacle distance information (e.g., "there is a road shoulder 20cm to the left"). After obtaining the obstacle distance information, the steer-by-wire system does not immediately output a full-power steering command, but instead controls the wheel-end steering actuator to output a small pulse current. The output torque corresponding to this current is approximately 5% to 8% of the rated torque, i.e., a test torque. The amplitude of this test torque is carefully designed. Its lower limit can effectively activate the sensor closed-loop link to complete the electrical path self-check, while its upper limit cannot overcome the static friction between the tire and the ground, thus ensuring that the test is completed before the front wheels actually deflect, achieving a safe and concealed "soft test". During the output of the test torque, the steer-by-wire system simultaneously performs high-frequency current sampling (sampling frequency not less than 1kHz), calculating the rate of change of the motor current di / dt in real time. This rate of change is the first current rate of change, reflecting the abrupt change in resistance experienced by the wheel-end steering actuator during movement: when the wheel-end steering actuator moves in free space, the current rate of change is gradual; when the wheel-end steering actuator collides with a hard obstacle, the current will experience a step-like surge in a very short time (less than 5ms). The steer-by-wire system compares the real-time calculated first current rate of change with a preset rate of change threshold (e.g., ...). If the first current change rate is greater than the preset change rate, it indicates that the wheel-end steering actuator may have collided with a hard obstacle. In this case, to prevent misjudging occasional transient road impacts (such as running over gravel) as collisions with hard obstacles, the steer-by-wire system does not immediately confirm this position as a limit position. Instead, it controls the wheel-end steering actuator to reverse by a preset small angle (e.g., 2°). This 2° is the preset retraction angle, used to release the position from the "suspected interference" state, preparing for subsequent secondary detection and verification. After the wheel-end steering actuator completes its reverse retraction, the steer-by-wire system controls the wheel-end steering actuator to move back to the original direction at a very low constant speed (e.g., 10 deg / s), that is, to move back to the original direction at the preset speed. During this process, high-frequency current sampling is performed again to obtain the second current change rate during the second movement, completing the secondary detection and verification. If a second touch at the same location detects an excessive rate of change in current (i.e., the second rate of change in current is also greater than the preset rate of change), the steer-by-wire system officially confirms that the location as a physical interference point (hard obstacle) and records the current movement position as a temporary mechanical limit position. Simultaneously, it restricts further movement of the actuator in that direction during the current power-on cycle. If the rate of change in current is normal during the second touch, the previous touch is determined to be an occasional transient impact from the road surface, and the previous record is erased. This temporary mechanical limit position is only valid within the current power-on cycle and is stored in volatile memory (RAM). It is automatically cleared after the vehicle is powered off and will not affect the next power-on. When the vehicle leaves this position (e.g., if the vehicle speed exceeds a preset speed threshold), the steer-by-wire system automatically clears the temporary limit record.

[0041] In some examples, it also includes: Obtain the target current command value and actual current feedback value of the tactile feedback actuator of the vehicle's steer-by-wire system; If the current deviation between the target current command value and the actual current feedback value is greater than the preset current deviation within a preset time, it is determined that a failure event has occurred in the tactile feedback actuator. In the event that the haptic feedback actuator has failed, the current vehicle speed is obtained, and the target damping torque value is determined based on the current vehicle speed; Based on the target damping torque value, the hysteresis damper of the vehicle's steer-by-wire system is controlled to apply a damping torque to the vehicle's steering wheel.

[0042] For example, during operation, the steer-by-wire system continuously acquires the target current command value and the actual current feedback value of the haptic feedback actuator. The target current command value is the desired output current value of the haptic feedback actuator, calculated by the steer-by-wire system based on the current driving conditions (such as vehicle speed and steering angle). The actual current feedback value is the actual current output value of the haptic feedback actuator. Together, they constitute the core monitoring parameters for determining whether the haptic feedback actuator is functioning correctly. The steer-by-wire system calculates the difference between the target current command value and the actual current feedback value in real time, obtaining the current deviation, and continuously monitors whether this current deviation exceeds a preset current deviation (such as 25% of the rated current or an absolute value greater than 10A) within a preset time (such as 8ms). If this current deviation continues to exceed the preset limit within the preset time, it indicates that the actual output of the haptic feedback actuator has seriously deviated from the system command, and the steer-by-wire system determines that a failure event has occurred in the haptic feedback actuator (such as current loop malfunction or decoupling failure). In the event of a failure in the feedback actuator, the steer-by-wire system immediately triggers a physical safety mechanism: it acquires the current vehicle speed and determines a target damping torque value based on that speed. This involves adjusting the damping torque in stages according to the vehicle speed (slightly higher damping at high speeds to maintain straight-line stability, and slightly lower damping at low speeds to facilitate safe parking). After determining the target damping torque value, the steer-by-wire system controls the hysteresis damper to apply a corresponding damping torque to the steering wheel. This is achieved by injecting a corresponding excitation current into the coil of the hysteresis damper through an independent backup power supply, generating a constant damping torque corresponding to the target value. This hysteresis damper is coaxially and parallelly mounted on the steering column with the feedback actuator, and its rotor is fixedly connected to the same steering shaft as the feedback actuator's rotor. During normal operation, the hysteresis damper coil is not energized, generating only a very small inherent remanent magnetic torque (less than 0.1 Nm). This torque can be dynamically compensated by the closed-loop control algorithm of the haptic feedback actuator, and the driver is completely unaware of its presence. When the haptic feedback actuator fails, the hysteresis damper coil is directly energized and activated without any mechanical switching action. It can seamlessly intervene within milliseconds, applying a damping torque to the steering wheel that matches the current vehicle speed. The drive coil of this hysteresis damper uses a fully isolated winding, and its control unit is integrated into an independent System Basis Chip (SBC). Even if the main control path is completely burned out, the mechanism can still operate independently based on the vehicle speed signal obtained by hard-wired transmission.

[0043] Furthermore, this application also proposes a safety control system for a vehicle steer-by-wire system, which is used to execute an embodiment of any of the above-mentioned safety control methods for a vehicle steer-by-wire system, specifically as follows: Figure 2 The diagram shown is a functional module schematic of a safety control system for a vehicle steer-by-wire system proposed in this application. The system includes: Data acquisition module 21 is used to acquire the current vehicle speed, current steering wheel speed, and target control torque of the main control path before the fault event occurs when a preset fault event occurs in the main control path; wherein the preset fault events include communication loss, logical operation abnormality, or shadow verification deviation. The handover duration determination module 22 is used to determine the torque handover duration based on the current vehicle speed and the current steering wheel speed; The control weight acquisition module 23 is used to acquire the first control weight of the main control path and the second control weight of the backup control path within the torque handover time; wherein, the first control weight decreases monotonically with the torque handover time, the second control weight increases monotonically with the torque handover time, and the sum of the first control weight and the second control weight is always equal to 1. The smooth switching execution module 24 controls the main control path and the backup control path to perform torque output operations within the torque handover time, based on the target control torque, the first control weight and the second control weight.

[0044] It should be noted that the above embodiments are merely best examples and are not intended to limit the implementation of this application.

[0045] Furthermore, such as Figure 3 As shown, this application embodiment also provides an electronic device 300, including a processor 310, a memory 320, and a computer program 321 stored in the memory 320 and executable on the processor. When the processor 310 executes the computer program 321, it implements the steps of any of the above-described vehicle steer-by-wire methods.

[0046] Since the electronic device described in this embodiment is a device used to implement a vehicle steer-by-wire method in the embodiments of this application, those skilled in the art can understand the specific implementation method and various variations of the electronic device in this embodiment based on the method described in the embodiments of this application. Therefore, how the electronic device implements the method in the embodiments of this application will not be described in detail here. Any device used by those skilled in the art to implement the method in the embodiments of this application falls within the scope of protection of this application.

[0047] In practical implementation, when the computer program 321 is executed by the processor, it can achieve the following: Figure 1 Any of the corresponding implementation methods in the embodiments.

[0048] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0049] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-readable program code.

[0050] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will 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 program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0051] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0052] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0053] This application also provides a computer program product, which includes computer software instructions that, when executed on a processing device, cause the processing device to execute a vehicle steer-by-wire method.

[0054] A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0055] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0056] In the several embodiments provided in this application, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between devices or units, and may be electrical, mechanical, or other forms.

[0057] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0058] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0059] If the integrated unit 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 application, in essence, or the part that contributes to the prior art, or all or 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 instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. 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.

[0060] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

[0061] Although preferred embodiments have been described in this specification, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this specification.

[0062] Obviously, those skilled in the art can make various modifications and variations to this specification without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims and their equivalents, this specification is also intended to include such modifications and variations.

Claims

1. A safety control method for a vehicle steer-by-wire system, characterized in that, The vehicle steer-by-wire system includes a main control path and a backup control path, and the method includes: In the event of a preset fault event in the main control path, the current vehicle speed, the current steering wheel speed, and the target control torque of the main control path before the fault event occurred are obtained; wherein, the preset fault event includes communication loss, logical operation abnormality, or shadow verification deviation; The torque handover duration is determined based on the current vehicle speed and the current steering wheel speed. Obtain the first control weight of the main control path and the second control weight of the backup control path within the torque handover time; wherein, the first control weight decreases monotonically with the torque handover time, the second control weight increases monotonically with the torque handover time, and the sum of the first control weight and the second control weight is always equal to 1; Based on the target control torque, the first control weight, and the second control weight, the main control path and the backup control path are controlled to perform torque output operations during the torque handover period.

2. The method according to claim 1, characterized in that, The step of obtaining the first control weight of the main control path and the second control weight of the backup control path within the torque handover time includes: Based on the torque handover duration, the start time of the torque handover duration, and the current time, determine the progress ratio within the torque handover duration at the current time; Based on the progress ratio, the first control weight and the second control weight corresponding to each moment within the torque handover duration are determined, wherein at the beginning of the torque handover duration, the first control weight is 1 and the second control weight is 0, and at the end of the torque handover duration, the first control weight is 0 and the second control weight is 1.

3. The method according to claim 1, characterized in that, The determination of torque handover duration based on the current vehicle speed and current steering wheel speed includes: When the current vehicle speed is greater than the first preset vehicle speed and the current steering wheel speed is greater than the first preset speed, the torque transfer duration is determined to be the first preset duration. When the current vehicle speed is less than the second preset vehicle speed and the current steering wheel rotation speed is less than the second preset rotation speed, the torque transfer duration is determined as the second preset duration; wherein, the first preset vehicle speed is greater than the second preset vehicle speed, and the second preset duration is greater than the first preset duration.

4. The method according to claim 1, characterized in that, The step of controlling the main control path and the backup control path to perform torque output operations during the torque handover period based on the target control torque, the first control weight, and the second control weight includes: Based on the target control torque and the first control weight, the target output torque of the main control path at each moment within the torque handover duration is determined; Based on the target control torque and the second control weight, the target output torque of the backup control path is determined at each moment within the torque handover duration; The main control path is controlled to perform torque output operation according to the target output torque at each moment within the torque transition period, and the backup control path is controlled to perform torque output operation according to the target output torque at each moment within the torque transition period.

5. The method according to claim 1, characterized in that, Also includes: The system acquires a first angle measurement value, a second angle measurement value, and a third angle measurement value from the wheel-end steering actuator in the vehicle steer-by-wire system; wherein, the first angle measurement value is used to characterize the measured steering angle; the second angle measurement value is used to characterize the steering angle determined based on the vehicle motor rotor position; and the third angle measurement value is used to characterize the steering angle determined based on the cross-axis current feedback value, the motor torque constant, the friction parameters, and the inertia parameters of the vehicle steer-by-wire system. Based on the first angle measurement value, the second angle measurement value, and the third angle measurement value, the target steering angle of the wheel-end steering actuator is determined.

6. The method according to claim 5, characterized in that, Determining the target steering angle of the wheel-end steering actuator based on the first angle measurement value, the second angle measurement value, and the third angle measurement value includes: Obtain a first difference between the first angle measurement value and the second angle measurement value, a second difference between the first angle measurement value and the third angle measurement value, and a third difference between the second angle measurement value and the third angle measurement value; If the first difference, the second difference, and the third difference are all less than or equal to a preset deviation threshold, the first angle measurement value is determined as the target steering angle. If the first difference is greater than the preset deviation threshold and the second difference is greater than the preset deviation threshold, the target steering angle is determined based on the second angle measurement value and the third angle measurement value.

7. The method according to claim 1, characterized in that, Also includes: Based on the operating status parameters of the vehicle steer-by-wire system, the power-on initialization state of the vehicle steer-by-wire system is determined; When the power-on initialization state is incomplete, obtain the obstacle distance information of the environment in which the vehicle's steer-by-wire system is located; Based on the obstacle distance information, the wheel-end steering actuator is controlled to output a trial torque; During the process of the wheel-end steering actuator outputting the test torque, the first current change rate of the wheel-end steering actuator is obtained; When the rate of change of the first current is greater than the preset rate of change, the steering actuator at the wheel end is controlled to move in the opposite direction by a preset retraction angle. After the wheel-end steering actuator moves in the opposite direction by a preset retraction angle, the wheel-end steering actuator is controlled to move back to the original direction at a preset speed, and the second current change rate during the second movement of the wheel-end steering actuator is obtained. If the second current change rate is greater than the preset change rate, the current movement position is recorded as a temporary mechanical limit position, and the movement range of the wheel-end steering actuator is limited based on the temporary mechanical limit position.

8. The method according to claim 1, characterized in that, Also includes: Obtain the target current command value and the actual current feedback value of the tactile feedback actuator of the vehicle's steer-by-wire system; If the current deviation between the target current command value and the actual current feedback value is greater than the preset current deviation within a preset time, it is determined that the tactile feedback actuator has failed. If a failure event is determined in the tactile feedback actuator, the current vehicle speed is obtained, and the target damping torque value is determined based on the current vehicle speed; Based on the target damping torque value, the hysteresis damper of the vehicle's steer-by-wire system is controlled to apply a damping torque to the vehicle's steering wheel.

9. A safety control system for a vehicle steer-by-wire system, characterized in that, include: The data acquisition module is used to acquire the current vehicle speed, the current steering wheel speed, and the target control torque of the main control channel before the occurrence of the fault event when a preset fault event occurs in the main control channel; wherein, the preset fault event includes communication loss, logical operation abnormality, or shadow verification deviation. The handover duration determination module is used to determine the torque handover duration based on the current vehicle speed and the current steering wheel speed; The control weight acquisition module is used to acquire the first control weight of the main control path and the second control weight of the backup control path within the torque handover time; wherein, the first control weight decreases monotonically with the torque handover time, the second control weight increases monotonically with the torque handover time, and the sum of the first control weight and the second control weight is always equal to 1. The smooth switching execution module controls the main control path and the backup control path to perform torque output operations within the torque handover period, based on the target control torque, the first control weight, and the second control weight.

10. An electronic device, comprising: The memory and processor are characterized in that the processor is used to execute a computer program stored in the memory to implement the steps of the safety control method for a vehicle steer-by-wire system as described in any one of claims 1 to 8.

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