Steering control method, system, program product, medium and device

Abstract

The application provides a steering control method, system, program product, medium and device, the steering control method comprises the following steps: collecting vehicle dynamic signals, the vehicle dynamic signals comprise steering wheel rotation angle; determining whether the vehicle is straight driving through the vehicle chassis domain controller according to the vehicle dynamic signals; in response to determining that the vehicle is straight driving, obtaining the shaft rotation angle detection value as the shaft rotation angle detection deviation value through the chassis domain controller; calculating the initial target shaft rotation angle according to the steering wheel rotation angle; calculating the corrected target shaft rotation angle according to the initial target shaft rotation angle and the shaft rotation angle detection deviation value; driving the steering motor to steer according to the corrected target shaft rotation angle, the method synchronizes the shaft rotation angle detection deviation value learned by the chassis domain to the steering control link, reduces the influence of detection error on steering response, and improves the accuracy of steering control and driving experience.

Description

Technical Field

[0001] This application relates to the field of steer-by-wire system control technology, specifically to a steering control method, system, program product, medium, and device. Background Technology

[0002] The steer-by-wire system eliminates the mechanical connection between the steering wheel and the steering actuator. The steering wheel module calculates the target axle angle based on the driver's input, and the steering module drives the wheels via a steering motor to make the actual axle angle follow the target value. Since there is no fixed mechanical steering ratio, the correspondence between the steering wheel angle and the axle angle is dynamically determined by a variable steering ratio strategy. Under ideal conditions where the axle angle sensor is error-free, the sensor reading equals the actual axle angle, and the system can accurately execute the driver's intentions.

[0003] However, in actual use, the axle angle sensor may experience zero-point offset due to factors such as temperature drift, aging from long-term use, or initial installation errors. In the inventor's known technology, the chassis domain controller can identify and compensate for this offset by combining signals such as wheel speed, yaw rate, and lateral acceleration through vehicle dynamic learning functions to ensure the normal operation of vehicle stability control functions. However, in the drive-by-wire steering system, this offset is only used by the chassis domain for stability control and is not synchronized to the steering wheel module for correction of the target axle angle. The resulting problem is that when the vehicle is traveling straight, the driver needs to keep the steering wheel at a non-zero angle to counteract the sensor offset. However, when making the same steering input to the left and right in this state, the actual axle angle changes inconsistently, exhibiting asymmetrical steering characteristics, which affects the driver's control feel of the vehicle. In addition, when the vehicle is also equipped with a rear axle drive-by-wire steering system and the rear axle angle sensor also has an offset, the driver cannot adjust the steering wheel to bring the actual angles of the front and rear axles to zero simultaneously, which may cause the vehicle to be unable to maintain straight-line driving.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] Depending on the specific aspects, one of the problems this application aims to solve is the steering asymmetry problem in steer-by-wire systems caused by uncorrected sensor deviations.

[0006] In addition, this application aims to solve or alleviate other technical problems existing in the prior art.

[0007] According to the first aspect of this application, the following is provided: A steering control method comprising the following steps: Collect vehicle dynamic signals, including steering wheel angle; The vehicle chassis domain controller determines whether the vehicle is traveling straight based on the vehicle dynamic signals. In response to the determination that the vehicle is traveling straight, the chassis domain controller obtains the axle angle detection value as the axle angle detection deviation value. Calculate the initial target axis rotation angle based on the steering wheel rotation angle; The corrected target axis rotation angle is calculated based on the deviation value between the initial target axis rotation angle and the detected axis rotation angle. The steering motor is driven to steer according to the corrected target axis angle.

[0008] According to a second aspect of this application, a steering control system is provided, comprising: Vehicle sensors that collect vehicle dynamic signals, including the steering wheel angle collected by a steering wheel angle sensor; The chassis domain controller determines whether the vehicle is traveling straight based on the vehicle dynamic signal, and in response to the determination that the vehicle is traveling straight, it acquires the axle angle detection value as the axle angle detection deviation value. The steering wheel module calculates an initial target shaft angle based on the steering wheel angle, and calculates a corrected target shaft angle based on the deviation value between the initial target shaft angle and the shaft angle detection value. The steering control module drives the steering motor to steer according to the corrected target axis angle.

[0009] According to a third aspect of this application, this application provides a computer program product, including a computer program that, when executed, implements the steering control method described above.

[0010] According to a fourth aspect of this application, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steering control method described above.

[0011] According to a fifth aspect of this application, this application provides a computer device including a storage module, a processor, and a computer program stored on the storage module and executable on the processor, wherein the processor executes the computer program to implement the steering control method described above.

[0012] The advantages of this application include at least the following: 1. The steering control method of this application synchronizes the axle angle detection deviation value learned in the chassis domain to the steering control loop. The sensor deviation is fed forward to compensate during the target axle angle calculation stage, which fundamentally eliminates the influence of sensor zero drift on steering response. The vehicle can be driven straight without the driver having to manually correct the steering wheel angle. 2. The steering control method of this application obtains the axle angle detection deviation value based on the judgment result of the chassis domain controller on the straight-line state of the vehicle. It utilizes the existing vehicle dynamic perception capability of the chassis domain, without the need to add additional hardware, and has a low implementation cost. 3. The steering control method proposed in one embodiment of this application calculates four types of yaw rates using multiple source signals such as wheel speed, yaw rate, lateral acceleration, and axle rotation angle, and uses a majority voting mechanism to determine whether the vehicle is going straight, which effectively avoids misjudgment of straight-going due to abnormal signals from a single sensor, and improves the robustness and safety of straight-going determination. 4. One embodiment of the steering control method proposed in this application sets a control accuracy threshold, and only updates the deviation value in the steering wheel module when the change in the shaft angle detection deviation value exceeds the threshold. This avoids frequent control and steering vibration caused by small fluctuations in the deviation value, and improves the control stability and driving smoothness of the system. Attached Figure Description

[0013] Referring to the accompanying drawings, the above and other features of this application will become apparent, wherein, Figure 1 A schematic flowchart of a steering control method according to one embodiment of this application is shown; Figure 2 A schematic diagram of a steering control system according to one embodiment of this application is shown. Detailed Implementation

[0014] It is readily understood that, based on the technical solution of this application, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of this application. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this application and should not be considered as the entirety of this application or as limitations or restrictions on the technical solution of this application.

[0015] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive. Furthermore, the terms "first," "second," "third," and similar expressions are used for descriptive and distinguishing purposes only and should not be construed as indicating or implying the relative importance of the corresponding components or the order of components or assembly sequence.

[0016] refer to Figure 1 This diagram illustrates a flow chart of a steering control method according to an embodiment of this application, where S100-S600 represent various method steps. This steering control method is used in steer-by-wire systems, for example, for precise control of the steer-by-wire system when a deviation occurs in the axle angle sensor, and includes the following steps: S100: Collects vehicle dynamic signals, including steering wheel angle; S200: The vehicle chassis domain controller determines whether the vehicle is going straight based on the vehicle dynamic signal; S300: In response to the determination that the vehicle is going straight, the chassis domain controller obtains the axle angle detection value as the axle angle detection deviation value. S400: Calculate the initial target axis rotation angle based on the steering wheel rotation angle; S500: Calculate the corrected target axis rotation angle based on the initial target axis rotation angle and the detected deviation value of the axis rotation angle; S600: Drive the steering motor to steer according to the corrected target axis rotation angle.

[0017] In this steering control method, vehicle dynamic signals are first acquired (e.g., through vehicle sensors), including the steering wheel angle (e.g., detected by a steering wheel angle sensor). Based on this, the vehicle chassis domain controller determines whether the vehicle is in a straight-line state according to the acquired vehicle dynamic signals. When the chassis domain controller determines that the vehicle is in a straight-line state, since the actual axle angle of the vehicle is zero degrees at this time, the chassis domain controller determines the current axle angle detection deviation value as the axle angle detection deviation value. The axle angle detection value is obtained, for example, directly through the axle angle sensor, but is not limited to obtaining it solely through direct detection. It can also be obtained by calculating the rotation angle of the steering gear rack or motor angle, or through other detection or calculation methods. This axle angle detection deviation value reflects the offset of the axle angle detection value from the true zero position, which may be caused by factors such as sensor temperature drift, long-term aging, initial installation errors, or gear rack transmission backlash and motor angle conversion errors.

[0018] After obtaining the axle angle detection deviation value, the method enters the target axle angle correction stage. Specifically, firstly, an initial target axle angle is calculated based on the steering wheel angle. This initial target axle angle reflects the axle angle expected to be achieved based on the driver's operating intention and the variable steering ratio strategy. Then, this initial target axle angle is superimposed with the axle angle detection deviation value learned by the chassis domain controller to calculate the corrected target axle angle, that is, the corrected target axle angle is equal to the sum of the initial target axle angle and the axle angle detection deviation value. Finally, the steering motor is driven to steer according to the corrected target axle angle.

[0019] During the steering motor operation, the steering module uses the corrected target axle angle as the control objective, driving the steering motor to make the detected axle angle equal to this corrected target axle angle. Since the actual axle angle equals the detected axle angle minus the detected axle angle deviation, the actual axle angle is exactly equal to the initial target axle angle corresponding to the driver's operating intention. This method introduces deviation compensation at the control objective level, ensuring that even if there is a zero-point offset in the axle angle detection, the vehicle's actual steering response remains precisely consistent with the driver's operating intention.

[0020] The aforementioned axle angle detection deviation value can be continuously learned and updated in real time during vehicle operation, enabling the method to adaptively compensate for the slow drift of the axle angle detection deviation over time. Once the detection deviation is correctly compensated, the driver can keep the vehicle traveling straight by returning the steering wheel to zero degrees while driving straight. Furthermore, when making the same steering input to the left and right, the actual axle angle changes are symmetrical and equal, resulting in completely consistent left and right steering characteristics. In addition, for vehicles equipped with both front and rear axle-controlled steering systems, this method can compensate for the axle angle detection deviation of the front and rear axles separately, ensuring that the driver can simultaneously return the actual steering angle of the front and rear axles to zero by adjusting the steering wheel, maintaining stable straight-line driving.

[0021] In one embodiment of this application, the vehicle dynamic signal includes wheel speed acquired by a wheel speed sensor, a first yaw rate acquired by a yaw rate sensor, and lateral acceleration acquired by a lateral acceleration sensor. The vehicle chassis domain controller determines that the vehicle is traveling straight based on the following condition: The wheel speed difference between each wheel is less than the preset wheel speed difference threshold; The lateral acceleration is less than a preset lateral acceleration threshold; The first yaw rate is less than a preset yaw rate threshold.

[0022] When executing the step "determining whether the vehicle is traveling straight based on the vehicle dynamic signals using the vehicle chassis domain controller," the chassis domain controller receives multiple dynamic signals from vehicle sensors in real time, specifically including: wheel speeds collected by wheel speed sensors, a first yaw rate collected by a yaw rate sensor, and lateral acceleration collected by a lateral acceleration sensor. The chassis domain controller judges each of these signals as follows: First, it calculates the difference between the wheel speeds and compares this difference with a preset wheel speed difference threshold; second, it compares the absolute value of the lateral acceleration with a preset lateral acceleration threshold; finally, it compares the absolute value of the first yaw rate with a preset yaw rate threshold. Only when all three conditions are met simultaneously—that is, the wheel speed difference is less than the wheel speed difference threshold, the lateral acceleration is less than the lateral acceleration threshold, and the first yaw rate is less than the yaw rate threshold—does the chassis domain controller determine that the vehicle is traveling straight.

[0023] The aforementioned thresholds are pre-calibrated positive values, and their specific values ​​can be set according to vehicle parameters and desired judgment sensitivity. For example, the wheel speed difference threshold can be calibrated to a value between 0.5 km / h and 2 km / h, the lateral acceleration threshold can be calibrated to a value between 0.05g and 0.15g, and the yaw rate threshold can be calibrated to a value between 0.5 deg / s and 2 deg / s. When all the above conditions are met, the actual axle rotation angle of the vehicle can be considered to be zero degrees. The chassis domain controller can then reliably determine the axle rotation angle detection value at this time as the axle rotation angle detection deviation value, providing accurate deviation input for subsequent target axle rotation angle correction. By using the above multi-condition joint judgment method, the risk of misjudgment that may be caused by relying on a single signal for straight-line judgment is avoided, improving the accuracy and reliability of deviation learning.

[0024] In one embodiment of this application, the method further includes the following steps: The second yaw rate is calculated based on the vehicle speed and the axle rotation angle collected by the axle rotation angle sensor; The wheel speed difference is calculated based on the wheel speed collected by the wheel speed sensor, and the third yaw rate is calculated based on the wheel speed difference. The fourth yaw rate is calculated based on the vehicle speed and the lateral acceleration collected by the lateral acceleration sensor. The vehicle is determined to be traveling straight if at least three of the first yaw rate, second yaw rate, third yaw rate, and fourth yaw rate are less than the yaw rate threshold.

[0025] In this implementation, when performing a straight-line determination, the chassis domain controller does not rely solely on a single source of yaw rate signal, but instead calculates four yaw rate values ​​through four independent methods. Specifically, the first yaw rate is directly acquired by the yaw rate sensor, reflecting the actual rotational angular velocity of the vehicle body around its vertical axis. The second yaw rate is calculated based on the current vehicle speed and the axle angle acquired by the axle angle sensor. Its calculation principle is based on the vehicle kinematics model, i.e., when the vehicle is turning, there is a definite geometric relationship between the vehicle speed and the axle angle, and the corresponding yaw rate can be calculated through this relationship. The third yaw rate is calculated based on the wheel speed difference of each wheel acquired by the wheel speed sensor, and then deduced from the wheel speed difference. Its principle is based on the correspondence between the rotational speed difference of the left and right wheels and the yaw rate when the vehicle is turning. The fourth yaw rate is calculated based on the current vehicle speed and the lateral acceleration collected by the lateral acceleration sensor. It is based on the physical relationship between the yaw rate, lateral acceleration and vehicle speed when the vehicle is in steady motion, that is, the yaw rate is equal to the lateral acceleration divided by the vehicle speed.

[0026] After obtaining the four yaw rates, the chassis domain controller compares the absolute value of each yaw rate with a preset yaw rate threshold and counts the number of yaw rates less than the threshold. This yaw rate threshold is a very small yaw rate value used to determine whether the vehicle is in a nearly straight-line state with almost no rotation. Its specific value can be pre-calibrated according to the vehicle type and control accuracy requirements, for example, between 0.5 deg / s and 2 deg / s. When the statistical result reaches three or more, that is, at least three of the four yaw rates are less than the yaw rate threshold, the chassis domain controller determines that the vehicle is in a straight-line state. In other words, as long as there are no two or more yaw rates exceeding the threshold, the straight-line determination is valid. Through this "majority vote" redundancy verification mechanism, even if a certain sensor (such as the yaw rate sensor or wheel speed sensor) outputs an abnormal value due to a fault or signal noise, as long as the yaw rate from the other three sources all indicate that the vehicle is in a straight-going state, the system can still correctly determine that the vehicle is going straight, thereby effectively avoiding misjudgment or missed judgment of straight-going due to the abnormality of a single sensor.

[0027] The aforementioned majority voting mechanism significantly improves the robustness and fault tolerance of straight-ahead determination. Taking a signal jump from the yaw rate sensor as an example: if the first yaw rate briefly exceeds the threshold due to sensor noise, but the second, third, and fourth yaw rates are all below the threshold, then three out of the four meet the straight-ahead condition. The chassis domain controller still determines the vehicle is going straight and normally acquires the axle angle detection deviation value; the system's straight-ahead determination function remains unaffected. Conversely, if two or more of the four yaw rates exceed the threshold, the system determines the vehicle is not in a straight-ahead state. In this case, the axle angle detection deviation value is not acquired, avoiding incorrect learning of deviation values ​​under non-straight-ahead conditions. The four yaw rates originate from different sensors or different physical calculation models, and their respective error sources are independent. The "majority rule" determination strategy effectively avoids interference from occasional anomalies of a single signal source on the straight-ahead determination result.

[0028] In one embodiment of this application, when only three of the first yaw rate, second yaw rate, third yaw rate, and fourth yaw rate are less than the yaw rate threshold, the following operations are performed respectively: If the first yaw rate is greater than the yaw rate threshold, the value of the first yaw rate is used as the yaw rate detection deviation value. If the second yaw rate is greater than the yaw rate threshold, the shaft rotation angle collected by the shaft rotation angle sensor at this time shall be the shaft rotation angle detection deviation value. If the third yaw rate is greater than the yaw rate threshold, then the wheel speed detection deviation value is calculated based on the wheel speeds of each wheel used to calculate the third yaw rate. If the fourth yaw rate is greater than the yaw rate threshold, the lateral acceleration collected by the lateral acceleration sensor at this time shall be taken as the lateral acceleration detection deviation value.

[0029] When the chassis domain controller determines that exactly three out of four yaw rates are less than the yaw rate threshold, it means that one yaw rate is greater than or equal to the threshold, while the other three are normal. This indicates that the vehicle is indeed traveling straight, but the sensor used to calculate or collect the abnormal yaw rate may be biased. In this case, the chassis domain controller performs different bias calculation operations based on the source of the abnormal yaw rate.

[0030] If the first yaw rate is greater than the yaw rate threshold, while the second, third, and fourth yaw rates are all less than the threshold, it indicates that the yaw rate sensor has zero drifted, and its detected value deviates from the true yaw rate (approximately zero). In this case, the chassis domain controller directly determines the detected value of the first yaw rate as the yaw rate detection deviation value, that is, the zero-point offset of the yaw rate sensor is equal to the current reading of the first yaw rate.

[0031] If the second yaw rate is greater than the yaw rate threshold, while the first, third, and fourth yaw rates are all less than the threshold, it indicates that the axle rotation angle sensor used to calculate the second yaw rate may have a zero-point offset. The axle rotation angle value it collects deviates from the true value, resulting in an abnormal calculated yaw rate. In this case, since the vehicle is actually traveling straight, the true axle rotation angle should be zero degrees. The chassis domain controller will determine the current detection value of the axle rotation angle sensor as the axle rotation angle detection deviation value.

[0032] If the third yaw rate is greater than the yaw rate threshold, while the first, second, and fourth yaw rates are all less than the threshold, it indicates that there may be a deviation in the wheel speed sensor group used to calculate the third yaw rate. That is, there is a discrepancy between the detected values ​​of one or more wheel speed sensors and the actual wheel speed, resulting in abnormal differences in the left and right wheel speeds, and consequently causing the calculated yaw rate to deviate from zero. In this case, the chassis domain controller further calculates the deviation value of each wheel speed sensor based on the current detected values ​​of each wheel speed sensor. The specific calculation method will be described in detail below.

[0033] If the fourth yaw rate is greater than the yaw rate threshold, while the first, second, and third yaw rates are all less than the threshold, it indicates that the lateral acceleration sensor may have a zero-point offset, causing the lateral acceleration it collects to deviate from the true value. This results in an abnormal yaw rate calculated based on the lateral acceleration and vehicle speed. In this case, since the vehicle is actually traveling straight, the true lateral acceleration should be zero. The chassis domain controller will then determine the current detection value of the lateral acceleration sensor as the lateral acceleration detection deviation value.

[0034] The aforementioned control method achieves precise localization of sensor deviation sources. When the chassis domain controller determines straight-line movement using a majority voting mechanism, only one of the four yaw rates will be abnormal. This abnormal value cannot originate from the vehicle's actual turning motion (since the other three independent sources all indicate straight-line movement), but must stem from a deviation in the sensor or computational component corresponding to that abnormal value. This method eliminates the need for additional reference sensors, automatically identifying and quantifying the zero-point offset of each sensor during normal vehicle operation, providing an accurate basis for subsequent sensor calibration. The located detection deviation values ​​can be recorded and used for subsequent signal correction: for example, the yaw rate detection deviation value can be used to correct the subsequently acquired first yaw rate; the axle rotation angle detection deviation value can be used as the aforementioned axle rotation angle detection deviation value for target axle rotation angle correction; and the lateral acceleration detection deviation value can be used to correct the subsequently acquired lateral acceleration signal, thereby improving the quality of each sensor signal and the overall control accuracy of the system.

[0035] In one embodiment of this application, calculating the wheel speed detection deviation value based on the wheel speeds of each wheel used in calculating the third yaw rate includes the following steps: Calculate the average wheel speed of the front axle and the average wheel speed of the rear axle; If the average wheel speed of the front axle is less than the average wheel speed of the rear axle, the average of the wheel speed of the high-speed wheel on the front axle and the wheel speed of the low-speed wheel on the rear axle is used as the reference wheel speed. If the average wheel speed of the front axle is greater than the average wheel speed of the rear axle, the average of the wheel speed of the low-speed wheel on the front axle and the wheel speed of the high-speed wheel on the rear axle is used as the reference wheel speed. The wheel speed correction factor for each wheel is obtained by referring to a table based on the reference wheel speed and the wheel speed of each wheel; The wheel speed detection deviation value of each wheel is calculated based on the wheel speed of each wheel and the wheel speed correction coefficient of each wheel.

[0036] When the chassis domain controller determines that the third yaw rate is abnormal (i.e., greater than the yaw rate threshold) while the other three yaw rates are normal, it means that the vehicle is actually traveling straight, but the yaw rate calculated based on the wheel speed difference deviates from zero. As mentioned earlier, the actual wheel speeds of all wheels should be equal in a straight-moving state. However, if one or more wheel speed sensors have detection deviations, the wheel speed detection values ​​of each wheel will be inconsistent, resulting in wheel speed differences, which in turn leads to an abnormal calculated third yaw rate. At this point, it is necessary to further locate which one or more of the wheel speed sensors are deviating and quantify their deviation values.

[0037] First, the average wheel speed of the two front axle wheels is calculated as the front axle average wheel speed, and the average wheel speed of the two rear axle wheels is calculated as the rear axle average wheel speed. The front axle average wheel speed is then compared with the rear axle average wheel speed. If the front axle average wheel speed is less than the rear axle average wheel speed, a lower-speed wheel is selected from the rear axle (higher wheel speed) and a higher-speed wheel is selected from the front axle (lower wheel speed), and the average of the two is used as the reference wheel speed. Conversely, if the front axle average wheel speed is greater than the rear axle average wheel speed, a lower-speed wheel is selected from the front axle and a higher-speed wheel is selected from the rear axle, and the average of the two is used as the reference wheel speed. The reference wheel speed represents a reasonable estimate of the actual wheel speed of each wheel under the current vehicle driving conditions, and its selection principle is to use relatively reliable wheel speeds as a benchmark as possible.

[0038] After obtaining the reference wheel speed, for each wheel of the vehicle, a wheel speed correction coefficient is obtained by looking up a table based on the reference wheel speed and the current wheel speed detection value of that wheel. This correction coefficient table is pre-established through bench or actual vehicle calibration and reflects the mapping relationship between the wheel speed sensor detection values ​​and the actual wheel speed under different wheel speed conditions. For example, for a certain wheel, when the reference wheel speed is V... ref The wheel speed sensor detected a value of V. sensor When the wheel speed sensor's nonlinear characteristics differ at different vehicle speeds, the correction coefficient table corresponding to that operating condition is the wheel's gain coefficient or offset correction amount under that condition. Since the table can be calibrated at multiple vehicle speed nodes, interpolation based on the actual vehicle speed can be used to obtain more accurate correction coefficients when looking up the table.

[0039] Finally, based on the wheel speed detection values ​​of each wheel and the corresponding wheel speed correction coefficients obtained from a lookup table, the wheel speed detection deviation value of each wheel is calculated. Specifically, for each wheel, the wheel speed detection deviation value can be the difference between the wheel speed detection value and the reference wheel speed after correction by the correction coefficient, or the offset obtained by subtracting the reference wheel speed multiplied by the correction coefficient from the wheel speed detection value. Through this method, the wheel speed detection deviation values ​​of each of the four wheels can be obtained separately, achieving precise quantification of the wheel speed sensor deviation.

[0040] The above method, through grouping and comparing the wheel speeds of the front and rear axles and appropriately selecting reference wheel speeds, can effectively separate the individual deviations of each wheel speed sensor when the vehicle is traveling straight. The calculated wheel speed detection deviation values ​​of each wheel can be recorded and used for subsequent correction of the wheel speed sensor signals to eliminate the influence of zero-point offset or gain deviation of the wheel speed sensor on the accuracy of the third yaw rate calculation. Simultaneously, the relative magnitudes of the wheel speed detection deviation values ​​can also be used to assist in determining whether a wheel speed sensor is faulty. For example, if the deviation value of one wheel is significantly greater than that of other wheels, it can be determined that the wheel speed sensor of that wheel is abnormal, thereby triggering the corresponding fault diagnosis or alarm mechanism.

[0041] In one embodiment of this application, the method further includes the following steps: Obtain the shaft rotation angle detection deviation value obtained by the chassis domain controller at the current moment, and record it as the current learning value; Obtain the shaft rotation angle detection deviation value used to calculate the corrected target shaft rotation angle at the previous moment, and record it as the current value; Calculate the absolute value of the difference between the current learned value and the current used value; When the absolute value of the difference is less than or equal to the preset control accuracy threshold, the current shaft rotation angle detection deviation value is not updated, and the current value remains unchanged. When the absolute value of the difference is greater than the preset control accuracy threshold, the current shaft rotation angle detection deviation value is updated to the current learning value.

[0042] During actual vehicle operation, the chassis domain controller continuously learns the axle angle detection deviation value. However, due to factors such as sensor signal noise, road bumps, or communication fluctuations, the learned deviation value may fluctuate slightly around the true value. If all these slight fluctuations are synchronized to the steering wheel module in real time and used for target axle angle correction, the corrected target axle angle will change frequently, leading to repeated fine-tuning of the steering motor, affecting driving smoothness and increasing system load. To solve this problem, this embodiment provides a deviation value update strategy with dead zone.

[0043] Specifically, during deviation value synchronization, the steering wheel module first acquires two values: the latest axle angle detection deviation value learned by the chassis domain controller at the current moment, denoted as the current learned value; and the axle angle detection deviation value actually used to calculate the corrected target axle angle at the previous moment, denoted as the current used value. Then, it calculates the absolute value of the difference between the current learned value and the current used value and compares this difference with a preset control accuracy threshold. This control accuracy threshold reflects the system's control resolution requirement for the axle angle detection deviation value, and its specific value can be pre-calibrated according to the control accuracy requirements of the steering system, for example, it can be calibrated to 0.02 degrees. When the absolute value of the difference is less than or equal to this control accuracy threshold, it indicates that the difference between the latest learned deviation value and the currently used deviation value is within the allowable range of system control accuracy. In this case, the steering wheel module refuses to update the current axle angle detection deviation value and continues to maintain the current used value, thereby avoiding frequent control caused by small fluctuations in the deviation value. Conversely, when the absolute value of the difference is greater than the control accuracy threshold, it indicates that the deviation value learned by the chassis domain controller has changed significantly beyond the system control accuracy. It is necessary to synchronize it to the steering wheel module to maintain the correction accuracy. At this time, the steering wheel module updates the current shaft angle detection deviation value to the current learned value.

[0044] Through the aforementioned dead-zone update strategy, the steering wheel module only performs an update operation when the change in deviation value exceeds a preset control accuracy threshold. This strategy, while ensuring control accuracy, effectively avoids frequent adjustments to the steering system caused by minor fluctuations in deviation value, reduces the burden on bus communication, and improves system control stability and driving smoothness. Furthermore, the control accuracy threshold can be flexibly calibrated according to actual system needs. For example, a smaller threshold can be used in high-speed driving conditions where high steering accuracy is required, while a larger threshold can be used in low-speed driving conditions where smoothness is more important, achieving an optimal balance between accuracy and smoothness.

[0045] In one embodiment of this application, the method further includes the following steps: When the absolute value of the difference is greater than the preset control accuracy threshold, the current used value is gradually transitioned to the current learned value according to the ramp function. The transition time or slope of the ramp function is calibrated based on the current vehicle speed; the higher the speed, the longer the transition time.

[0046] When the absolute value of the difference between the axle angle detection deviation value learned by the chassis domain controller (current learned value) and the deviation value currently being used by the steering wheel module (current used value) exceeds a preset control accuracy threshold, the deviation value in the steering wheel module needs to be updated to the latest learned value. However, if the current used value is switched instantaneously to the current learned value, the corrected target axle angle may undergo a step change, leading to a sudden change in steering motor control commands, which in turn causes abrupt changes in steering wheel feel, affecting driving comfort and safety. To solve this problem, this implementation uses a ramp function to achieve a smooth transition of the deviation value.

[0047] Specifically, when the absolute value of the difference exceeds the control accuracy threshold, the steering wheel module does not immediately jump the deviation value to the current learned value. Instead, it gradually transitions the current used value to the current learned value according to a preset ramp function. During the transition, the deviation value starts from the initial value (i.e., the current used value) and changes linearly with time at a certain slope until it reaches the target value (i.e., the current learned value). After the transition is complete, the deviation value stabilizes at the current learned value and is used as the new current used value for subsequent target axis steering angle calculations. If the chassis domain controller issues a new learned value during the ramp transition, the steering wheel module can stop the current ramp and restart the transition process based on the new difference to ensure that the deviation value always converges to the latest learned value.

[0048] The transition time or slope of the ramp function is not fixed but calibrated based on the vehicle's current speed. Generally, the higher the vehicle speed, the more sensitive the vehicle is to steering disturbances. In this case, a longer transition time (i.e., a gentler slope) is needed to gradually update the deviation value, avoiding sudden changes in the vehicle's yaw rate due to rapid changes in the deviation value at high speeds, thus ensuring high-speed stability. Conversely, at low speeds, the vehicle is less sensitive to steering disturbances, and a shorter transition time (i.e., a steeper slope) can be used to quickly update the deviation value, enabling the system to respond promptly to changes in the deviation value. The above correspondence between vehicle speed and transition time can be predetermined through bench or real-vehicle calibration and stored in the vehicle's calibration parameter table. During actual operation, the chassis domain controller or steering wheel module looks up the corresponding transition time or slope in real time based on the current vehicle speed.

[0049] Through the aforementioned ramp transition method, the shaft angle detection deviation value in the steering wheel module can smoothly change from the old value to the new value, effectively avoiding the step change in steering control command caused by sudden changes in deviation value, ensuring that the target shaft angle output by the steering wheel module changes continuously after correction, and improving driving smoothness and vehicle handling stability.

[0050] In one embodiment of this application, when the absolute value of the difference is greater than the preset control accuracy threshold, it is further determined whether the duration of the deviation between the current learning value and the current used value exceeds a preset time threshold; only when the duration of the deviation exceeds the time threshold is the current shaft rotation angle detection deviation value updated.

[0051] During actual vehicle operation, the axle angle detection deviation value learned by the chassis domain controller may experience brief fluctuations due to factors such as signal noise, communication interruptions, or occasional road impacts. For example, when a vehicle travels over a bumpy road, the wheel speed signal may fluctuate instantaneously, causing the deviation value calculated by the chassis domain controller to deviate from the true value for a very short time before quickly recovering. Although a control accuracy threshold has been set in the above implementation to determine whether the change in the deviation value has reached the level requiring an update, if the threshold is used as the sole criterion, the system will still trigger an update when the deviation value briefly exceeds the threshold due to instantaneous noise, leading to unnecessary control actions.

[0052] To address this issue, this implementation further incorporates a time dimension judgment based on the condition that "the absolute value of the difference is greater than the control accuracy threshold." Specifically, when the absolute value of the difference between the current learned value and the current used value is detected to be greater than the control accuracy threshold, the chassis domain controller or steering wheel module does not immediately perform an update. Instead, it begins timing and continuously monitors whether the deviation remains. The system only updates the current shaft angle detection deviation value if the absolute value of the difference remains greater than the control accuracy threshold for a period exceeding a preset time threshold. If, during the timing process, the absolute value of the difference falls back to within the control accuracy threshold, the timing is reset to zero, and no update is triggered. This time threshold can be pre-calibrated based on sensor noise characteristics, communication cycle, and control response speed requirements.

[0053] Through the aforementioned duration determination mechanism, brief, instantaneous signal spikes or occasional communication fluctuations are filtered out because they fail to meet the duration requirement and will not trigger an update of the deviation value. Only when the deviation value undergoes a sustained, non-instantaneous, real change that meets the time threshold condition will the system perform an update operation. This effectively avoids erroneous deviation value updates caused by sensor signal noise, occasional communication fluctuations, or instantaneous road surface interference, further enhancing the anti-interference capability and system robustness of synchronous deviation value updates.

[0054] In one embodiment of this application, the method further includes the following steps: Real-time acquisition of the initial target axis rotation angle; In response to the absolute value of the current initial target axis rotation angle being greater than the preset rotation angle threshold, the current axis rotation angle detection deviation value is directly updated to the current learning value.

[0055] Under normal operating conditions, the axle angle detection deviation value learned by the chassis domain controller is synchronized to the steering wheel module. That is, the deviation value in the steering wheel module is only updated when the change in the deviation value exceeds the control accuracy threshold, and optionally, the duration exceeds the time threshold. However, in certain special conditions, such as when the driver makes a sharp turn while the vehicle is driving straight and then returns the steering wheel to center, if the deviation value has not yet been synchronized to the steering wheel module, the vehicle may still be unable to drive straight after the steering wheel is returned to center, requiring the driver to make additional adjustments to the steering wheel angle. In this case, if the deviation value is still updated gradually according to the conventional dead-zone strategy, the driver's driving experience will be adversely affected. To solve this problem, this embodiment introduces a forced update strategy based on the initial target axle angle size.

[0056] Specifically, the steering wheel module acquires the initial target axle angle in real time during vehicle operation. This initial target axle angle is a target value calculated based on the steering wheel angle without deviation correction, reflecting the driver's current steering intention. The steering wheel module simultaneously monitors the absolute value of this initial target axle angle and compares it with a preset angle threshold. When the absolute value of the initial target axle angle exceeds the preset angle threshold, it indicates that the driver has performed a significant steering operation. In this case, the steering wheel module skips the control accuracy threshold judgment and directly updates the current axle angle detection deviation value to the latest learned value obtained by the chassis domain controller. This angle threshold can be pre-calibrated based on the response characteristics of the vehicle steering system. Through this forced update strategy, when the driver performs a significant steering operation, the system can quickly complete the synchronous update of the deviation value, allowing the driver to resume straight driving without additional correction after straightening the steering wheel, eliminating the interference of sensor deviation on driving control under extreme conditions.

[0057] In summary, the steering control method of this application synchronizes the axle angle detection deviation value learned from the chassis domain to the steering control stage, and achieves feedforward compensation during the target axle angle calculation stage, so that the actual axle angle is exactly equal to the driver's intention value. It can maintain straight driving without the driver having to make additional corrections to the steering wheel angle, and the left and right steering characteristics are symmetrical and consistent. This reduces the impact of detection error on steering response and improves the accuracy of steering control and driving experience.

[0058] refer to Figure 2 This diagram illustrates a block diagram of a steering control system 10 according to one embodiment of the present application. The steering control system 10 includes: Vehicle sensor 100 collects vehicle dynamic signals, including the steering wheel angle collected by steering wheel angle sensor; The chassis domain controller 200 determines whether the vehicle is traveling straight based on the vehicle dynamic signal, and in response to the determination that the vehicle is traveling straight, acquires the axle angle detection value as the axle angle detection deviation value. The steering wheel module 300 calculates an initial target shaft angle based on the steering wheel angle, and calculates a corrected target shaft angle based on the detected deviation value between the initial target shaft angle and the shaft angle. The steering control module 400 drives the steering motor to steer according to the corrected target axis angle.

[0059] This steering control system possesses all the beneficial technical effects of the aforementioned steering control method, which will not be repeated here. Those skilled in the art should understand that each technical feature in the foregoing method embodiments can be implemented in hardware or software by one or more modules in the aforementioned system. Therefore, this steering control system possesses all the technical features completely corresponding to the foregoing method embodiments, which will not be repeated here.

[0060] A third aspect of this application provides a computer program product, including a computer program that, when executed, implements the steering control method described above.

[0061] A fourth aspect of this application provides a computer-readable storage medium on which a computer program is stored, which, when executed by a processor, implements the steering control method described above.

[0062] The fifth aspect of this application provides a computer device including a storage module, a processor, and a computer program stored on the storage module and executable on the processor, wherein the processor executes the computer program to implement the steering control method described above.

[0063] Those skilled in the art will understand that all or part of the processes in the steering control method of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which includes, but is not limited to, program code for executing the steering control method described above. For ease of explanation, only the parts relevant to this application are shown. The computer program code can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium can include any entity or device capable of carrying the computer program code, a medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. It should be noted that the content contained in the computer-readable storage medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0064] It should be understood that all the above preferred embodiments are exemplary and not restrictive, and various modifications or variations made by those skilled in the art to the specific embodiments described above under the concept of this application should be within the scope of legal protection of this application.

Claims

1. A steering control method, characterized in that, Includes the following steps: Collect vehicle dynamic signals, including steering wheel angle; The vehicle chassis domain controller determines whether the vehicle is traveling straight based on the vehicle dynamic signals. In response to the determination that the vehicle is traveling straight, the chassis domain controller obtains the axle angle detection value as the axle angle detection deviation value. Calculate the initial target axis rotation angle based on the steering wheel rotation angle; The corrected target axis rotation angle is calculated based on the deviation value between the initial target axis rotation angle and the detected axis rotation angle. The steering motor is driven to steer according to the corrected target axis angle.

2. The steering control method according to claim 1, characterized in that, The corrected target axis rotation angle is determined based on the sum of the initial target axis rotation angle and the axis rotation angle detection deviation value.

3. The steering control method according to claim 1, characterized in that, The shaft rotation angle detection value is obtained by the shaft rotation angle sensor.

4. The steering control method according to claim 1, characterized in that, The shaft rotation angle detection value is obtained by calculating the rotation angle of the steering gear rack or the motor rotation angle.

5. The steering control method according to claim 3, characterized in that, The vehicle dynamic signals include wheel speed collected by wheel speed sensors, first yaw rate collected by yaw rate sensors, and lateral acceleration collected by lateral acceleration sensors. The vehicle chassis domain controller determines that the vehicle is traveling straight based on the following conditions: The wheel speed difference between each wheel is less than the preset wheel speed difference threshold; The lateral acceleration is less than a preset lateral acceleration threshold; The first yaw rate is less than a preset yaw rate threshold.

6. The steering control method according to claim 5, characterized in that, Includes the following steps: The second yaw rate is calculated based on the vehicle speed and the axle rotation angle collected by the axle rotation angle sensor; The wheel speed difference is calculated based on the wheel speed collected by the wheel speed sensor, and the third yaw rate is calculated based on the wheel speed difference. The fourth yaw rate is calculated based on the vehicle speed and the lateral acceleration collected by the lateral acceleration sensor. The vehicle is determined to be traveling straight if at least three of the first yaw rate, second yaw rate, third yaw rate, and fourth yaw rate are less than the yaw rate threshold.

7. The steering control method according to claim 6, characterized in that, If only three of the first, second, third, and fourth yaw angular velocities are less than the yaw angular velocity threshold, the following operations are performed respectively: If the first yaw rate is greater than the yaw rate threshold, the value of the first yaw rate is used as the yaw rate detection deviation value. If the second yaw rate is greater than the yaw rate threshold, the shaft rotation angle collected by the shaft rotation angle sensor at this time shall be the shaft rotation angle detection deviation value. If the third yaw rate is greater than the yaw rate threshold, then the wheel speed detection deviation value is calculated based on the wheel speeds of each wheel used to calculate the third yaw rate. If the fourth yaw rate is greater than the yaw rate threshold, the lateral acceleration collected by the lateral acceleration sensor at this time shall be taken as the lateral acceleration detection deviation value.

8. The steering control method according to claim 7, characterized in that, The calculation of the wheel speed detection deviation value based on the wheel speeds of each wheel used in calculating the third yaw rate includes the following steps: Calculate the average wheel speed of the front axle and the average wheel speed of the rear axle; If the average wheel speed of the front axle is less than the average wheel speed of the rear axle, the average of the wheel speed of the high-speed wheel on the front axle and the wheel speed of the low-speed wheel on the rear axle is used as the reference wheel speed. If the average wheel speed of the front axle is greater than the average wheel speed of the rear axle, the average of the wheel speed of the low-speed wheel on the front axle and the wheel speed of the high-speed wheel on the rear axle is used as the reference wheel speed. The wheel speed correction factor for each wheel is obtained by referring to a table based on the reference wheel speed and the wheel speed of each wheel; The wheel speed detection deviation value of each wheel is calculated based on the wheel speed of each wheel and the wheel speed correction coefficient of each wheel.

9. The steering control method according to claim 1, characterized in that, Includes the following steps: Obtain the shaft rotation angle detection deviation value obtained by the chassis domain controller at the current moment, and record it as the current learning value; Obtain the shaft rotation angle detection deviation value used to calculate the corrected target shaft rotation angle at the previous moment, and record it as the current value; Calculate the absolute value of the difference between the current learned value and the current used value; When the absolute value of the difference is less than or equal to the preset control accuracy threshold, the current shaft rotation angle detection deviation value is not updated, and the current value remains unchanged. When the absolute value of the difference is greater than the preset control accuracy threshold, the current shaft rotation angle detection deviation value is updated to the current learning value.

10. The steering control method according to claim 9, characterized in that, Includes the following steps: When the absolute value of the difference is greater than the preset control accuracy threshold, the current used value is gradually transitioned to the current learned value according to the ramp function. The transition time or slope of the ramp function is calibrated based on the current vehicle speed; the higher the speed, the longer the transition time.

11. The steering control method according to claim 9, characterized in that, When the absolute value of the difference is greater than the preset control accuracy threshold, it is further determined whether the duration of the deviation between the current learning value and the current usage value exceeds the preset time threshold; only when the duration of the deviation exceeds the time threshold is the current shaft rotation angle detection deviation value updated.

12. The steering control method according to claim 9, characterized in that, Includes the following steps: Real-time acquisition of the initial target axis rotation angle; In response to the absolute value of the current initial target axis rotation angle being greater than the preset rotation angle threshold, the current axis rotation angle detection deviation value is directly updated to the current learning value.

13. A steering control system, characterized in that, include: Vehicle sensors that collect vehicle dynamic signals, including the steering wheel angle collected by a steering wheel angle sensor; The chassis domain controller determines whether the vehicle is traveling straight based on the vehicle dynamic signal, and in response to the determination that the vehicle is traveling straight, it acquires the axle angle detection value as the axle angle detection deviation value. The steering wheel module calculates an initial target shaft angle based on the steering wheel angle, and calculates a corrected target shaft angle based on the deviation value between the initial target shaft angle and the shaft angle detection value. The steering control module drives the steering motor to steer according to the corrected target axis angle.

14. A computer program product, comprising a computer program, characterized in that, When the computer program is executed, it implements the steering control method according to any one of claims 1 to 12.

15. A computer-readable storage medium on which a computer program is stored, characterized in that, When the computer program is executed by the processor, it implements the steering control method according to any one of claims 1 to 12.

16. A computer device comprising a storage module, a processor, and a computer program stored on the storage module and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steering control method according to any one of claims 1 to 12.

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