A rear wheel steering control method, system, device, storage medium, and vehicle

Abstract

The application discloses a rear wheel steering control method, system, device, storage medium and vehicle. The rear wheel steering control method is applied to a vehicle with a rear wheel steering system, and the rear wheel steering system comprises a lead screw for controlling rear wheel steering of the vehicle. The method comprises the following steps: in response to the rear wheel starting to steer, the actual position angle of the lead screw and the target position angle of the lead screw are obtained, the difference between the actual position angle and the target position angle is determined as the position angle deviation of the lead screw, the vehicle speed of the vehicle is obtained, and the first preset threshold is obtained according to the vehicle speed; and according to the position angle deviation being greater than or equal to the first preset threshold, the rear wheel steering system is controlled to correct the rear wheel. When the position angle deviation of the lead screw exceeds the first preset threshold, the rear wheel can be corrected in time, so that the lateral force of the vehicle body is reduced, and the function safety of the whole vehicle is ensured.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and in particular to a rear-wheel steering control method, system, device, storage medium, and vehicle. Background Technology

[0002] As people's pursuit of driving convenience continues to increase, more and more vehicles on the market are now equipped with active rear-wheel steering systems to enhance product competitiveness. Because active rear-wheel steering systems have a significant impact on the overall handling stability of the vehicle, and are drive-by-wire products, their functional safety is particularly important. Inappropriate functional safety control strategies can affect user experience or endanger user safety.

[0003] In related technologies, when controlling rear-wheel steering, the friction coefficient and external load of the rear wheels can easily change due to the influence of external road conditions, such as asphalt, cement, ice, etc. This can easily cause the system to overshoot the rear wheel steering angle. The rear wheel steering angle controlled by the active rear wheel steering system has a great impact on the handling stability of the vehicle. A 1° rear wheel steering angle can generate a lateral force of more than 1000N. Unexpected rear wheel steering angle deviation can cause the vehicle to veer, fishtail, or even roll over, resulting in property damage and threatening the lives of the driver and passengers. Summary of the Invention

[0004] Therefore, one objective of this invention is to provide a rear wheel steering control method, system, device, storage medium, and vehicle that can promptly control the rear wheels to return to center when the position angle deviation of the lead screw exceeds a threshold, thereby reducing the lateral force on the vehicle body and ensuring the overall vehicle safety.

[0005] According to a first aspect of the present invention, a rear-wheel steering control method is applied to a vehicle having a rear-wheel steering system, the rear-wheel steering system including a lead screw for controlling the rear-wheel steering of the vehicle, the rear-wheel steering control method comprising: in response to the rear wheels starting to turn, acquiring an actual position angle of the lead screw and a target position angle of the lead screw, determining the difference between the actual position angle and the target position angle as a position angle deviation of the lead screw, and acquiring a first preset threshold based on the vehicle speed; and controlling the rear-wheel steering system to straighten the rear wheels if the position angle deviation is greater than or equal to the first preset threshold.

[0006] The rear-wheel steering control method according to embodiments of the present invention has at least the following beneficial effects:

[0007] This invention can determine whether the rear wheel steering is overshooting by judging whether the position angle deviation of the lead screw is greater than the first preset threshold corresponding to the current vehicle speed. In other words, the steering angle deviation of the rear wheels is judged by the position angle deviation of the lead screw, and the result is relatively accurate. When the position angle deviation of the lead screw is greater than the first preset threshold, it indicates that the rear wheel steering is overshooting. At this time, the rear wheel steering system is used to control the rear wheels to return to the center position, which can be understood as the rear wheels returning to the zero position, which can reduce the lateral force of the vehicle body and ensure the functional safety of the entire vehicle.

[0008] According to some embodiments of the present invention, the rear wheel steering control method further includes the following steps: in response to the rear wheel completing steering, when the position angle deviation is less than zero and the absolute value of the position angle deviation is greater than or equal to the first preset threshold, controlling the rear wheel to continue steering until the lead screw reaches the target position angle.

[0009] According to some embodiments of the present invention, controlling the rear wheel to return to center based on the position angle deviation being greater than or equal to the first preset threshold includes: determining a second preset threshold based on the first preset threshold, wherein the second preset threshold is less than the first preset threshold; when the position angle deviation is greater than or equal to the second preset threshold, controlling the lead screw to decelerate to zero at a preset deceleration and rotate at a preset safe speed until the actual position angle is zero.

[0010] According to some embodiments of the present invention, determining the second preset threshold based on the first preset threshold includes: calculating the second preset threshold using the following formula: Wherein, the first preset threshold is the maximum tolerable value δ for the angular deviation of the rear wheel. zmi The second preset threshold is δ smi The rotational speed of the lead screw is V. si The system's preset response time is t. f The preset deceleration of the lead screw is a. si .

[0011] According to some embodiments of the present invention, the preset safety speed is less than the preset deceleration.

[0012] According to some embodiments of the present invention, the vehicle is inversely proportional to the first preset value.

[0013] According to a second aspect of the present invention, a rear wheel steering control system includes: an acquisition unit, configured to acquire the vehicle speed and the actual position angle and target position angle of a lead screw controlling the rear wheel steering; a processing unit, configured to determine that the difference between the actual position angle and the target position angle is the position angle deviation of the lead screw, and to determine a first preset threshold corresponding to the vehicle speed; and a control unit, configured to control the rear wheels to return to center based on the position angle deviation being greater than or equal to the first preset threshold.

[0014] The rear-wheel steering control system according to embodiments of the present invention has at least the following beneficial effects: The present invention can determine whether the rear-wheel steering is overshooting by judging whether the position angle deviation of the lead screw is greater than the first preset threshold corresponding to the current vehicle speed. Judging the rear wheel steering angle deviation by the position angle deviation of the lead screw is relatively accurate. When the position angle deviation of the lead screw is greater than the first preset threshold, it indicates that the rear wheel steering is overshooting. At this time, controlling the rear wheels to return to center through the rear-wheel steering system can be understood as returning the rear wheels to the zero position, which can reduce the lateral force of the vehicle body and ensure the functional safety of the entire vehicle.

[0015] According to a third aspect of the present invention, a rear-wheel steering control device includes: at least one processor; at least one memory for storing at least one program; when the at least one program is executed by the at least one processor, the at least one processor implements the rear-wheel steering control method as described in the first aspect of the present invention.

[0016] The rear wheel steering control device according to the embodiments of the present invention has at least the above-described beneficial effects since its processor implements the rear wheel steering control method of the above embodiments, and will not be repeated here.

[0017] A vehicle according to a fourth aspect of the present invention includes a rear-wheel steering control system according to a second aspect or a rear-wheel steering control device according to a third aspect.

[0018] The vehicle according to the embodiments of the present invention, having included the rear-wheel steering control system of the second aspect embodiment or the rear-wheel steering control device of the third aspect, has at least the above-mentioned beneficial effects, which will not be repeated here.

[0019] A computer-readable storage medium according to a fifth aspect of the present invention stores processor-executable instructions, which, when executed by a processor, are used to perform the rear-wheel steering control method of the first aspect embodiment.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0022] Figure 1 This is a flowchart illustrating the steps of a rear-wheel steering control method according to some embodiments of the present invention;

[0023] Figure 2 This is a flowchart illustrating the steps of a rear-wheel steering control method according to some embodiments of the present invention;

[0024] Figure 3 This is a flowchart illustrating the steps of a rear-wheel steering control method according to some embodiments of the present invention;

[0025] Figure 4 This is a schematic diagram of the rear wheel steering in some embodiments of the present invention;

[0026] Figure 5 This is a schematic diagram of the rear wheel steering in some embodiments of the present invention;

[0027] Figure 6 This is a schematic diagram of the functional modules of the active rear wheel steering control system in some embodiments of the present invention;

[0028] Figure 7 This is a graph showing the relationship between the speed and time of the lead screw in some embodiments of the present invention;

[0029] Figure 8 This is a flowchart illustrating the functional operation of the active rear-wheel steering control system in some embodiments of the present invention.

[0030] Figure 9 This is an example diagram showing the maximum tolerance value of rear wheel angle deviation under different vehicle speed ranges in some embodiments of the present invention;

[0031] Figure 10 This is a schematic diagram of the rear wheel steering control system according to some embodiments of the present invention;

[0032] Figure 11 This is a schematic diagram of the rear wheel steering control device according to some embodiments of the present invention.

[0033] Figure label:

[0034] Rear wheel 100, initial position 101, current position 102. Detailed Implementation

[0035] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0036] Reference Figure 1 The diagram illustrates a rear-wheel steering control method according to some embodiments of the present invention. The rear-wheel steering control method includes steps S100 and S200. This method is applied to vehicles with rear wheels and a rear-wheel steering system. The rear-wheel steering system includes a motor and a lead screw. The motor drives the lead screw to rotate, and the lead screw converts the rotational motion output by the motor into linear motion, thereby allowing the lead screw to steer the rear wheels.

[0037] In step S100: In response to the rear wheel starting to steer, the actual position angle and the target position angle of the lead screw are obtained, the difference between the actual position angle and the target position angle is determined as the position angle deviation of the lead screw, and a first preset threshold is obtained according to the vehicle speed.

[0038] In this step, when the driver turns the steering wheel, the steering wheel input signal is sent to the rear-wheel steering system. The rear-wheel steering system can then detect that the rear wheels are beginning to turn. Based on the steering wheel's rotation amplitude, the rear-wheel steering system calculates the target position angle of the lead screw and the time required for the motor to output power. The motor transmits power to the lead screw, causing it to rotate, which in turn drives the rear wheels. The actual position angle of the lead screw is obtained from sensors on the lead screw. Subtracting the target position angle from the actual position angle yields the lead screw's position angle deviation. Since the lead screw drives the rear wheels, this deviation can be understood as the rear wheel's steering angle deviation. It should be noted that the lead screw's position angle deviation is unpredictable and varies with environmental factors. Then, the vehicle speed is obtained, and a first preset threshold is obtained based on the vehicle speed. It should be noted that the first preset threshold is different for different vehicle speeds. The higher the vehicle speed, the smaller the first preset threshold. At high vehicle speeds, the vehicle is unstable under force and the safety risk is greater. Therefore, the requirement for the steering angle deviation of the rear wheels is higher. It can be understood that the vehicle speed and the first preset threshold are inversely proportional.

[0039] Step S200: When the position angle deviation is greater than or equal to the first preset threshold, control the rear wheel steering system to straighten the rear wheels.

[0040] In this step, if the deviation of the lead screw's position angle is greater than or equal to the first preset threshold, it indicates that the deviation exceeds the preset value, meaning the rear wheel steering angle deviation exceeds the preset value. This can be understood as the rear wheel steering system overshooting the rear wheels, mainly due to external road conditions such as asphalt, cement, or ice surfaces, which can easily cause changes in the rear wheel's friction coefficient and external load. At this time, controlling the rear wheel steering system to slowly return the rear wheels to center, or straightening them, allows them to return to their initial position. Specifically, the rear wheel steering system control motor drives the lead screw to rotate in the opposite direction, which in turn drives the rear wheels back to center, reducing the lateral force generated by the rear wheels and ensuring the vehicle's overall safety. It should be noted that when the vehicle requires steering, since the front wheels can steer normally, the rear wheels will not hinder steering even if they return to center. In this embodiment, this can be understood as entering a zero-return mode, allowing the rear wheels to return to the zero position.

[0041] It should be noted that in this embodiment, the steering angle deviation of the rear wheel is determined by the position angle deviation of the lead screw, which is relatively accurate. However, the steering angle of the rear wheel is affected by the deformation of the rubber bushing, etc., and directly obtaining the steering angle of the rear wheel through the steering angle sensor is not accurate enough.

[0042] Reference Figure 4 and Figure 5 As shown, in some embodiments, the position angle deviation of the lead screw is δ. si The actual position angle of the lead screw is δ sai The target position angle of the lead screw is δ sti δ si =δ sai -δ sti δ sai and δ sti All calculations start from 0°, and when the leadscrew rotates to δ... sai When in position, the rear wheel rotates by an angle θ1, δ. sti The required angle for the lead screw to reach can also be understood as the angle at which the lead screw needs to rotate to δ when the rear wheel 100 reaches the target angle of θ2. sti The corresponding position. It should be noted that the rear wheel 100 has an initial position 101 and a current position 102. When the rear wheel 100 is in the initial position 101, the steering angle of the rear wheel 100 is 0, and the corresponding actual position angle δ of the lead screw is... sai It is also 0. When the lead screw controls the rear wheel 100 to start turning, the rear wheel 100 can swing from 0° to 90°. The rear wheel 100 swings from the initial position 101 to the current position 102. When the rear wheel 100 reaches the current position 102, δ sai Greater than 0.

[0043] Specifically, there are two situations where the position of the lead screw deviates. The first is: reference... Figure 4 As shown, when δ sai >δ sti At that time, δ si >0 can be interpreted as the rear wheels turning 100 degrees beyond the target position, causing the rear wheel steering system to overshoot, resulting in the rear wheels turning 100 degrees out of position. Furthermore, if δ si If it is greater than the first preset threshold, it means δ si If the value is too large, the rear wheel steering system control motor will drive the lead screw to rotate in the opposite direction. The lead screw will cause the rear wheel 100 to swing towards 0° until the rear wheel 100 returns to its initial position 101. (Refer to...) Figure 5 As shown, when δ sai <δ sti At that time, δ si <0 can be interpreted as the rear wheel steering system understeering the rear wheel 100. The rear wheel 100 is not fully steered and is in a safe position. At this time, there is no need to straighten the rear wheel 100 to meet the vehicle's steering requirements.

[0044] Understandably, referring to Figure 5 As shown, when δ sai <δ sti Furthermore, when the rear wheel 100 completes its turn, it indicates that the rear wheel 100 has not yet fully turned. If |δ si If the distance is greater than a first preset value, it indicates that the rear wheel 100 is far from its current position and the degree to which the rear wheel 100 has not turned into position is relatively large. At this time, the rear wheel 100 can be controlled to continue turning into position. Based on this, in some embodiments, the rear wheel steering control method further includes step S300.

[0045] Specifically, refer to Figure 2 As shown, in step S300: In response to the rear wheel completing the steering, when the position angle deviation is less than zero and the absolute value of the position angle deviation is greater than the first preset threshold, the rear wheel is controlled to continue steering until the lead screw reaches the target position angle.

[0046] In this step, when the rear wheel completes steering, it can also be understood that the rotational speed of the lead screw is 0, and the lead screw no longer drives the rear wheel to continue steering. At this time, if the absolute value of the lead screw's position angle deviation is |δ si If the value is greater than the first preset value, the rear wheels can be controlled to continue turning, allowing the lead screw to rotate to the target position angle, thus turning the rear wheels into position and making the vehicle steering more accurate. It should be noted that in this step, controlling the rear wheels to continue turning can be understood as the rear wheels starting to turn. The system can respond to this, that is, after executing step S300, step S100 can be executed according to the response conditions. If it is determined that the conditions for executing step S300 are met, step S300 is executed again to allow the rear wheels to continue turning. If it is determined that the conditions for executing step S200 are met, step S200 is executed.

[0047] In some embodiments, the first preset value is set as the maximum tolerance value δ for the rear wheel angle deviation. zmi It should be noted that δ zmi δ was obtained through CAE and real vehicle calibration for different vehicle speed ranges. zmi The values ​​of δ are different, if δ si Exceeding δ zmi This indicates a large deviation in the rear wheel steering angle, resulting in a significant lateral force on the vehicle and making driving more dangerous. Specifically, refer to... Figure 9 As shown, multiple speed ranges V are divided within the commonly used vehicle speed range. zi A vehicle speed range V zi Corresponding to a δ zmi As the vehicle speed increases, δ zmi The smaller the value, and the greater the vehicle speed, the greater the vehicle speed range V. zi The larger the coverage area.

[0048] It should be noted that, referring to Figure 4 As shown, when δ sai >δ sti At that time, δ si >0 can be understood as the rear wheels turning 100 degrees beyond the target position, causing the rear wheel steering system to overshoot. In this case, if δ si Greater than δ zmi The system initially controls the motor to drive the lead screw in reverse. However, in practice, it takes time for the motor to drive the lead screw to decelerate to zero. Furthermore, the system needs reaction time from receiving the deceleration command to implementing the deceleration measure. This can cause the lead screw to continue driving the rear wheel in the correct direction during this period, resulting in δ... si It increased further, exceeding δ zmi The range of δ is therefore required for determination. si Give an advance notice.

[0049] Based on this, in some embodiments, the step of controlling the subsequent cycle to return to the initial position according to the position angle deviation being greater than or equal to a first preset threshold in step S200 specifically includes steps S201 and S202.

[0050] Specifically, refer to Figure 3 As shown, step S201: Determine the second preset threshold based on the first preset threshold, where the second preset threshold is less than the first preset threshold.

[0051] In this step, since the second preset threshold is less than the first preset threshold, it can be understood that an advance allowance has been given, and δ is determined by the second preset value. siThis allows the rear wheels to begin returning to center earlier. In some embodiments, the second preset threshold can be obtained by subtracting a constant value from the first preset threshold. This constant value can be selected through extensive experiments or experience. The constant value cannot be too large or too small. If the constant value is too large, the second preset threshold will be too small, which may easily trigger the rear wheels to return to center erroneously. If the constant value is too small, the second preset threshold will be too large, resulting in δ si The value exceeds δ zmi excessive.

[0052] Step S202: When the position angle deviation is greater than or equal to the second preset threshold, control the lead screw to decelerate to zero at a preset deceleration and rotate at a preset safe speed until the actual position angle of the lead screw is zero.

[0053] In this step, the position angle deviation δ is determined. si When the value is less than the second preset threshold, the subsequent cycle is controlled to be positive, at which point δ si The first preset threshold δ was not reached. zmi This is equivalent to controlling the lead screw to decelerate to 0 in advance, preventing the lead screw from continuing to drive the rear wheel and causing δ to... si Exceeding δ zmi Excessive speed setting provides a lead time, ensuring timely control of the rear wheels to straighten and guaranteeing overall vehicle safety. The preset deceleration and preset safe speed can be selected based on actual vehicle conditions. In some embodiments, the preset deceleration and preset safe speed can be selected based on the current vehicle speed; the higher the speed, the lower the preset deceleration and preset safe speed. In some embodiments, the preset safe speed can be lower than the preset deceleration to prevent excessive rear wheel steering speed during straightening, thus ensuring overall vehicle safety.

[0054] In some embodiments, a second preset threshold can be calculated based on the deceleration characteristics of the lead screw's rotation speed. Specifically, the first preset threshold is the maximum tolerable value δ for the angular deviation of the rear wheel. zmi The second preset threshold is δ smi The preset rotation speed of the lead screw is V. si The preset reaction time of the rear wheel steering system is t. f The preset deceleration of the lead screw is a. si According to the formula: The second preset threshold δ can be calculated. smi The numerical value.

[0055] It needs to be explained that, referring to Figure 7 The graph shown is a relationship between the screw speed V and time t. It can be understood as forming a speed function V(t): t→V. The integral value of the speed function V(t) over the interval [0, t0] is equal to the actual position angle δ of the screw at time t0. saiThis can also be understood as the area enclosed by the line segment representing the screw speed V and the time axis t being equal to the actual position angle δ of the screw. sai The lead screw speed V is the preset rotational speed of the lead screw. si When the leadscrew steers the rear wheels, the leadscrew rotates at a constant speed; therefore, the leadscrew speed V remains constant. Specifically, if the steering system overshoots the rear wheels, at some point before t1, δ si It will equal 0. At time t1, the system determines δ. si equal to δ smi And δ si It will soon be greater than δ smi The system issues a deceleration control command to the motor. Because the system requires a certain response time, it only begins to control the motor to reverse at time t2. This can be understood as t2 being the moment the system begins to take action. In the above formula, t... f =t1-t2,t f This can be understood as the reaction time from when the rear-wheel steering system recognizes and issues a deceleration signal to when it takes deceleration measures, t f Depending on the internal communication cycle and controller hardware, a si This is obtained by combining measurements of motor drive characteristics. Furthermore, in the above formula... This can be understood as being caused by δ zmi Subtracting gives δ smi The value, It equals the integral value of the velocity function V(t) over the interval [t1, t3], where t3 is the moment when the screw velocity V equals 0. This can be understood as... It is exactly equal to the area of ​​the trapezoid formed by the line segment of the lead screw speed V from time t1 to the time when the lead screw speed V reaches 0 and the time t axis. When the lead screw speed V decreases to 0, δ si Just equal to δ zmi .

[0056] For example, at a certain vehicle speed, δ zmi =4°, δ smi =3.5°, When δ is detected si =δ smi When the angle is 3.5°, the lead screw is controlled to decelerate at a preset rate a. si Deceleration to 0; during this process, since the lead screw speed V is not 0, δ si It will continue to increase as the lead screw speed V decreases at a preset deceleration a. si When decelerating to 0, δ si The increment is the area of ​​the trapezoid mentioned above, that is... Therefore, δ si It will increase to 4°, which is exactly equal to δ. zmi Therefore, in this embodiment, δ is obtained according to the above formula.smi Then, and with δ smi For δ si Make a judgment; if δ can be controlled relatively well. si The degree of change.

[0057] It should be noted that δ smi and V si For mutual adjustment quantities, if δ smi The setting is too large, the system is very robust, but V si If the required value is too small, it will affect the system response speed; if δ is too small... smi The setting is too small, V si A large configurable size results in fast system response, but also weakens system robustness and makes it susceptible to environmental influences. Both aspects need to be balanced through real-vehicle calibration to ensure functional safety while achieving optimal response speed, thereby enhancing the overall competitiveness of the vehicle.

[0058] Reference Figure 10 The diagram shown illustrates a rear-wheel steering control system according to some embodiments of the present invention. The rear-wheel steering control system includes an acquisition unit, a processing unit, and a control unit. The acquisition unit acquires the vehicle speed and the actual and target position angles of the lead screw controlling the rear wheel steering. The processing unit determines the difference between the actual and target position angles as the position angle deviation of the lead screw, and determines a first preset threshold corresponding to the vehicle speed. The control unit controls the rear wheels to return to center if the position angle deviation is greater than or equal to the first preset threshold. (Refer to...) Figure 6 As shown, the rear-wheel steering control system includes an ECU unit and an active rear-wheel steering actuator. The ECU unit can be understood as the processing unit mentioned above, and the active rear-wheel steering actuator can be understood as the control unit mentioned above. The ECU unit includes a comprehensive judgment module, which receives the system hardware fault code signal G. d Vehicle speed signal V zi δ, the actual position angle signal of the lead screw sai Target position angle signal δ of the lead screw sti Screw speed signal V si The input is evaluated and judged.

[0059] Reference Figure 6 and Figure 7 The diagram shown is a flowchart of the rear wheel steering control system according to some embodiments of the present invention. First, the start step S10 is executed, then step S20 is executed to obtain vehicle status information. In step S30, it is identified whether the vehicle has a hardware fault. If there is no hardware fault, Gd = 0. Then, in step S40, a comprehensive judgment is performed to determine δ. si ≥δ smiWhen this happens, step S60 is executed to enter the zero-return mode, which means the rear wheel returns to positive. Specifically, this can be understood as executing step S200 above. When δ is determined... si <δ smi When the time comes, step S50 is executed to enter the normal mode, which means that the rear wheels are turned normally without any intervention to the rear wheels.

[0060] This invention also provides a rear wheel steering control device, which includes at least one processor and at least one memory. The memory is used to store at least one program. When the at least one program is executed by the at least one processor, the above-described rear wheel steering control method is implemented.

[0061] This invention also provides a computer-readable storage medium storing a processor-executable computer program, which, when executed by a processor, is used to implement the aforementioned rear-wheel steering control method.

[0062] This invention also provides a vehicle including the rear-wheel steering control system or rear-wheel steering control device described above. Since the vehicle employs the rear-wheel steering control system or rear-wheel steering control device described above, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated further here.

[0063] In some embodiments, the vehicle includes a front-wheel steering system that provides steering wheel angle information, and a rear-wheel steering system that can steer according to the front wheel angle. The rear-wheel steering system generally includes an electronic control unit, a rear-wheel steering actuator, etc., and is equipped with detection devices for system hardware faults, vehicle speed, target position angle of the lead screw, actual position angle of the lead screw, and lead screw speed, providing signals such as system hardware fault codes, vehicle speed, target position angle of the lead screw, actual position angle of the lead screw, and lead screw speed.

[0064] Specifically, the vehicle can be a private car, such as a sedan, SUV, MPV, or pickup truck. The vehicle can also be a commercial vehicle, such as a van, bus, small truck, or large semi-trailer. The vehicle can be a gasoline-powered vehicle or a new energy vehicle. When the vehicle is a new energy vehicle, it can be a hybrid vehicle or a pure electric vehicle.

[0065] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0066] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0067] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0068] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatuses.

[0069] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0070] In the several embodiments provided in this application, it should be understood that the disclosed systems, 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 couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, apparatuses, or units, and may be electrical, mechanical, or other forms.

[0071] In this application embodiment, the terms "module" or "unit" refer to a computer program or part of a computer program that has a predetermined function and works with other related parts to achieve a predetermined goal, and can be implemented wholly or partially using software, hardware (such as processing circuitry or memory), or a combination thereof. Similarly, a processor (or multiple processors or memory) can be used to implement one or more modules or units. Furthermore, each module or unit can be part of an overall module or unit that includes the functionality of that module or unit.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] The step numbers in the above method embodiments are set only for ease of explanation and do not impose any restrictions on the order of the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

Claims

1. A rear-wheel steering control method, characterized in that, Applied to vehicles with a rear-wheel steering system, the rear-wheel steering system including a lead screw for controlling the rear-wheel steering of the vehicle, the rear-wheel steering control method includes: In response to the rear wheels starting to steer, the actual position angle of the lead screw and the target position angle of the lead screw are obtained, the difference between the actual position angle and the target position angle is determined as the position angle deviation of the lead screw, and a first preset threshold is obtained according to the vehicle speed. When the position angle deviation is greater than or equal to the first preset threshold, the rear wheel steering system is controlled to straighten the rear wheels. The step of controlling the rear wheel steering system to straighten the rear wheels when the position angle deviation is greater than or equal to the first preset threshold includes: Acquire system hardware fault code signals to identify whether the vehicle has a hardware fault; In the absence of hardware failure, a second preset threshold is determined based on the first preset threshold, wherein the second preset threshold is less than the first preset threshold; When the position angle deviation is greater than zero and greater than or equal to the second preset threshold, the rear wheel steering system will overshoot the rear wheel, enter the zero-return mode, control the lead screw to decelerate to zero at a preset deceleration and rotate at a preset safe speed until the actual position angle is zero.

2. The rear-wheel steering control method according to claim 1, characterized in that, The rear-wheel steering control method further includes the following steps: In response to the rear wheel completing steering, when the position angle deviation is less than zero and the absolute value of the position angle deviation is greater than or equal to the first preset threshold, the rear wheel is controlled to continue steering until the lead screw reaches the target position angle.

3. The rear-wheel steering control method according to claim 1, characterized in that, The step of determining the second preset threshold based on the first preset threshold includes: The second preset threshold is calculated using the following formula: Wherein, the first preset threshold is the maximum tolerable value δ for the angular deviation of the rear wheel. zmi The second preset threshold is δ smi The preset rotation speed of the lead screw is V. si The preset reaction time of the rear wheel steering system is t. f The preset deceleration of the lead screw is a. si .

4. The rear-wheel steering control method according to claim 1, characterized in that, The vehicle speed is inversely proportional to the first preset threshold.

5. A rear-wheel steering control system, characterized in that, Applied to vehicles with a rear-wheel steering system, the rear-wheel steering system including a lead screw for controlling the rear-wheel steering of the vehicle, the rear-wheel steering control system including: The acquisition unit is used to acquire the vehicle speed and the actual and target position angles of the lead screw that controls the rear wheel steering. The processing unit is used to determine the difference between the actual position angle and the target position angle as the position angle deviation of the lead screw, and to determine the first preset threshold corresponding to the vehicle speed; The control unit is used to control the rear wheel steering system to straighten the rear wheels when the position angle deviation is greater than or equal to the first preset threshold. The step of controlling the rear wheel steering system to straighten the rear wheels when the position angle deviation is greater than or equal to the first preset threshold includes: Acquire system hardware fault code signals to identify whether the vehicle has a hardware fault; In the absence of hardware failure, a second preset threshold is determined based on the first preset threshold, wherein the second preset threshold is less than the first preset threshold; When the position angle deviation is greater than zero and greater than or equal to the second preset threshold, the rear wheel steering system will overshoot the rear wheel, enter the zero-return mode, control the lead screw to decelerate to zero at a preset deceleration and rotate at a preset safe speed until the actual position angle is zero.

6. A rear-wheel steering control device, characterized in that, include: At least one processor; At least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the rear wheel steering control method as described in any one of claims 1 to 4.

7. A computer-readable storage medium storing processor-executable instructions, characterized in that, The processor-executable instructions, when executed by the processor, are used to perform the rear wheel steering control method as described in any one of claims 1 to 4.

8. A vehicle, characterized in that, Includes the rear wheel steering control system as described in claim 5 or the rear wheel steering control device as described in claim 6.

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