Rear-wheel steering control method, device, rear-wheel steering controller and medium for vehicles

Abstract

The present application relates to a vehicle rear-wheel steering control method, device, rear-wheel steering controller, and medium. The method comprises: receiving a vehicle's steering angle signal; determining the vehicle's front and rear wheel steering angles based on the steering angle signal; and correcting the rear wheel steering angle based on the front wheel steering angle and the vehicle's current operating conditions to obtain a target steering angle for the vehicle's rear wheels. This control controls the vehicle's rear drive motor to adjust the internal rack position so that the actual steering angle of the rear wheels is consistent with the target steering angle. This solves the technical problem in related technologies of difficulty in balancing ride comfort and steering comfort due to space limitations, which hinders reducing turning diameter.

Description

Technical Field

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

[0002] In related technologies, the rear-wheel steering control method is based on the front wheel steering angle, taking into account different vehicle speeds and multiplying by a corresponding coefficient (or considering the overall vehicle posture), ultimately outputting the corresponding rear wheel steering angle. While this control method is relatively simple, in practical applications, due to space constraints, it significantly encroaches on the rear underbody and passenger compartment space, restricting the body and interior / exterior structures, reducing passenger space and ride comfort. Therefore, while prioritizing comfort, this technology requires limiting the rear wheel steering angle, making it difficult to achieve a large angle and hindering the reduction of turning diameter, thus requiring further improvement. Summary of the Invention

[0003] This application provides a rear-wheel steering control method, device, rear-wheel steering controller, and medium for a vehicle, in order to solve the technical problem in the related art that, due to space limitations, it is difficult to balance ride comfort and steering comfort, which is not conducive to reducing the turning diameter.

[0004] The first aspect of this application provides a rear-wheel steering control method for a vehicle, applied to a rear-wheel steering controller, wherein the method includes the following steps: receiving a steering angle signal of the vehicle; determining the front wheel steering angle and the rear wheel steering angle of the vehicle based on the steering angle signal; correcting the rear wheel steering angle by combining the front wheel steering angle and the current operating condition of the vehicle to obtain a target steering angle of the rear wheels of the vehicle, so as to control the rear drive motor of the vehicle to adjust the internal rack position so that the actual steering angle of the rear wheels is consistent with the target steering angle.

[0005] Optionally, in one embodiment of this application, when the current operating condition is a preset parking condition, the step of correcting the rear wheel angle by combining the front wheel angle and the current operating condition of the vehicle to obtain the target angle of the rear wheel includes: acquiring the unsprung acceleration signal of the vehicle; obtaining the road surface condition of the current driving road of the vehicle based on the unsprung acceleration signal; and correcting the rear wheel angle based on the road surface condition to obtain the target angle.

[0006] Optionally, in one embodiment of this application, when the current working condition is a preset parking condition, the step of correcting the rear wheel angle by combining the front wheel angle and the current working condition of the vehicle to obtain the target angle of the rear wheel further includes: acquiring the suspension travel signal of the vehicle; obtaining the wheel travel of the vehicle based on the suspension travel signal; determining whether the wheel travel is greater than a first preset threshold; if the wheel travel is greater than the first preset threshold, then limiting the rear wheel angle by combining a first preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to a first preset angle.

[0007] Optionally, in one embodiment of this application, when the current operating condition is a preset driving condition, the step of correcting the rear wheel angle by combining the front wheel angle and the current operating condition of the vehicle to obtain the target angle of the rear wheel includes: acquiring the inertial measurement unit signal of the vehicle; obtaining the roll state of the vehicle based on the inertial measurement unit signal; and correcting the rear wheel angle by combining the current vehicle speed, the roll state, the front wheel angle and the road surface condition to obtain the target angle.

[0008] Optionally, in one embodiment of this application, when the current operating condition is a preset driving condition, the step of correcting the rear wheel angle by combining the front wheel steering angle and the current operating condition of the vehicle to obtain the target steering angle of the vehicle's rear wheels further includes: determining whether the current vehicle speed is greater than a preset speed threshold; if the current vehicle speed is less than or equal to the preset speed threshold, then determining that the preset driving condition is a low-speed driving condition, and determining whether the wheel jump travel is greater than a second preset threshold, wherein if the wheel jump travel is greater than the second preset threshold, then limiting the rear wheel steering angle by combining a second preset weighting coefficient, so as to adjust the maximum steering angle of the vehicle's rear wheels to... The second preset angle, wherein the second preset threshold is greater than the first preset threshold, and the second preset weighting coefficient is obtained from the current vehicle speed; if the current vehicle speed is greater than the preset speed threshold, then the preset image is determined to be a medium-high speed driving condition, to determine whether the wheel jump travel is greater than the third preset threshold, wherein if the wheel jump travel is greater than the third preset threshold, then the rear wheel angle is limited in combination with the third preset weighting coefficient, so as to adjust the maximum rear wheel angle of the vehicle to the third preset angle, wherein the third preset threshold is greater than the second preset threshold, and the third preset weighting coefficient is obtained from the current vehicle speed.

[0009] A second aspect of this application provides a rear-wheel steering control device for a vehicle, applied to a rear-wheel steering controller. The device includes: a receiving module for receiving a vehicle's steering angle signal; a determining module for determining the front wheel steering angle and rear wheel steering angle of the vehicle based on the steering angle signal; and a control module for correcting the rear wheel steering angle by combining the front wheel steering angle and the vehicle's current operating condition to obtain a target steering angle for the vehicle's rear wheels, thereby controlling the rear drive motor of the vehicle to adjust the internal rack position so that the actual steering angle of the rear wheels matches the target steering angle.

[0010] Optionally, in one embodiment of this application, when the current working condition is a preset parking condition, the control module includes: a first acquisition unit, used to acquire the unsprung acceleration signal of the vehicle; a second acquisition unit, used to obtain the road surface condition of the current driving road of the vehicle based on the unsprung acceleration signal; and a first correction unit, used to correct the rear wheel steering angle based on the road surface condition to obtain the target steering angle.

[0011] Optionally, in one embodiment of this application, when the current working condition is a preset parking condition, the control module further includes: a third acquisition unit, used to acquire the suspension travel signal of the vehicle; a fourth acquisition unit, used to obtain the wheel travel of the vehicle based on the suspension travel signal; a first judgment unit, used to judge whether the wheel travel is greater than a first preset threshold; and a limiting unit, used to limit the rear wheel angle by combining a first preset weighting coefficient when the wheel travel is greater than the first preset threshold, so as to adjust the maximum rear wheel angle of the vehicle to a first preset angle.

[0012] Optionally, in one embodiment of this application, when the current operating condition is a preset driving condition, the control module includes: a fifth acquisition unit, used to acquire the inertial measurement unit signal of the vehicle; a sixth acquisition unit, used to obtain the roll state of the vehicle based on the inertial measurement unit signal; and a second correction unit, used to correct the rear wheel angle by combining the current vehicle speed, the roll state, the front wheel angle, and the road surface condition to obtain the target angle.

[0013] Optionally, in one embodiment of this application, when the current operating condition is a preset driving condition, the control module further includes: a second judgment unit, used to judge whether the current vehicle speed is greater than a preset speed threshold; and a first adjustment unit, used to determine that the preset driving condition is a low-speed driving condition when the current vehicle speed is less than or equal to the preset speed threshold, and to judge whether the wheel jump travel is greater than a second preset threshold, wherein if the wheel jump travel is greater than the second preset threshold, the rear wheel angle is limited by a second preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to the second preset angle. The second preset threshold is greater than the first preset threshold, and the second preset weighting coefficient is obtained from the current vehicle speed; the second adjustment unit is used to determine that the preset condition is a medium-high speed driving condition when the current vehicle speed is greater than the preset speed threshold, so as to determine whether the wheel jump travel is greater than the third preset threshold. If the wheel jump travel is greater than the third preset threshold, the rear wheel angle is limited by the third preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to the third preset angle. The third preset threshold is greater than the second preset threshold, and the third preset weighting coefficient is obtained from the current vehicle speed.

[0014] A third aspect of this application provides a rear-wheel steering controller, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the rear-wheel steering control method for a vehicle as described in the above embodiments.

[0015] A fourth aspect of this application provides a computer-readable storage medium storing computer instructions for causing the computer to perform the rear-wheel steering control method for a vehicle as described in the above embodiments.

[0016] A fifth aspect of this application provides a computer program product, including a computer program that, when executed, implements the above-described rear-wheel steering control method for a vehicle.

[0017] This application embodiment can determine the front and rear wheel steering angles of a vehicle based on its steering angle signals. By combining the front wheel steering angles with the vehicle's current operating conditions, the rear wheel steering angle is corrected to obtain the target steering angle for the rear wheels. This allows for the control of the rear drive motor to adjust the internal rack position, ensuring the actual rear wheel steering angle matches the target angle. This logical control of the rear wheel steering angle addresses user needs under different operating conditions, achieving a larger rear wheel steering angle within the same layout space. This reduces the turning radius and minimizes the encroachment of rear wheel steering on the rear underbody and passenger compartment, saving development costs, increasing passenger space, and improving ride comfort. Therefore, it solves the technical problem in related technologies where space constraints make it difficult to balance ride comfort and steering comfort, hindering the reduction of turning diameter.

[0018] Additional aspects and advantages of this application 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 this application. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 This is a flowchart of a rear-wheel steering control method for a vehicle according to an embodiment of this application;

[0021] Figure 2 This is a schematic diagram illustrating the principle of a rear-wheel steering control method for a vehicle according to an embodiment of this application.

[0022] Figure 3 This is a schematic diagram illustrating the rear wheel steering control principle under parking conditions according to an embodiment of this application;

[0023] Figure 4 This is a schematic diagram of the rear wheel steering control principle under low-speed conditions according to an embodiment of this application;

[0024] Figure 5 This is a schematic diagram of the rear wheel steering control principle under medium-to-high speed conditions according to an embodiment of this application;

[0025] Figure 6 This is a schematic diagram of the structure of a rear wheel steering control device for a vehicle according to an embodiment of this application;

[0026] Figure 7 This is a schematic diagram of the structure of the rear wheel steering controller provided according to an embodiment of this application. Detailed Implementation

[0027] The embodiments of this application 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 intended to explain this application, and should not be construed as limiting this application.

[0028] The following description, with reference to the accompanying drawings, describes a rear-wheel steering control method, device, controller, and medium for a vehicle according to embodiments of this application. Addressing the technical problem mentioned in the background art, where space constraints make it difficult to balance ride comfort and steering comfort, hindering the reduction of turning diameter, this application provides a rear-wheel steering control method for a vehicle. In this method, the front and rear wheel steering angles of the vehicle are determined based on the vehicle's steering angle signal. The rear wheel steering angle is then corrected by combining the front wheel steering angle with the vehicle's current operating condition to obtain a target steering angle for the rear wheels. This allows for the control of the rear drive motor to adjust the internal rack position, ensuring the actual rear wheel steering angle matches the target angle. This provides logical control of the rear wheel steering angle to meet user needs under different operating conditions. Within the same space, a larger rear wheel steering angle can be achieved, reducing the turning radius and minimizing the encroachment of rear-wheel steering on the rear underbody and passenger compartment space. This saves development costs, increases user seating space, and improves ride comfort. This solves the technical problem in related technologies where space constraints make it difficult to balance ride comfort and steering comfort, which is not conducive to reducing turning diameter.

[0029] Specifically, Figure 1 This is a schematic flowchart illustrating a rear-wheel steering control method for a vehicle provided in an embodiment of this application.

[0030] like Figure 1 As shown, the rear-wheel steering control method for this vehicle is applied to the rear-wheel steering controller, and the method includes the following steps:

[0031] In step S101, the vehicle's turning angle signal is received.

[0032] In actual implementation, the embodiments of this application can generate a corresponding steering angle signal based on the steering wheel angle, so as to perform rear wheel steering control based on the steering angle signal in subsequent processes.

[0033] In step S102, the front wheel steering angle and rear wheel steering angle of the vehicle are determined based on the steering angle signal.

[0034] As one possible implementation method, embodiments of this application can determine the front wheel steering angle and rear wheel steering angle of a vehicle based on steering angle signals and the vehicle's driving speed.

[0035] For example, in a front-wheel steering vehicle, the relationship between the steering wheel angle and the wheel angle can be expressed as:

[0036]

[0037] Based on this, the actual steering angle of the vehicle can be obtained by combining the vehicle speed.

[0038] In four-wheel steering vehicles, the rear wheels can also steer to improve vehicle agility or stability. In this case, the steering direction and angle of the rear wheels may differ from those of the front wheels, and this is typically controlled by the ECU (Electronic Control Unit) based on vehicle speed and other sensor data.

[0039] In step S103, the rear wheel angle is corrected by combining the front wheel angle and the current working condition of the vehicle to obtain the target angle of the rear wheel, so as to control the rear drive motor of the vehicle to adjust the internal rack position so that the actual angle of the rear wheel is consistent with the target angle.

[0040] Understandably, the steering angle of the rear wheels is controlled by the signal from the rear wheel steering controller. After receiving the steering angle signal, the controller of the rear wheel steering gear itself drives the motor to adjust the position of the internal rack, thereby driving the toe-in linkage to move, and finally achieving rear wheel steering.

[0041] In related technologies, the actual steering angle of the rear wheels is obtained by multiplying the steering angle of the front wheels by a corresponding coefficient (or by considering the overall vehicle posture) based on different vehicle speeds.

[0042] In practical applications, due to space constraints, it is difficult to achieve a large horizontal rear wheel turning angle. Therefore, its contribution to the vehicle's minimum turning radius is very limited, and it also encroaches on a significant amount of passenger compartment space.

[0043] Therefore, the embodiments of this application can logically control the rear wheel steering angle according to the user's needs for different working conditions. Under the same layout space, a larger rear wheel steering angle can be achieved, which can not only reduce the turning radius, but also reduce the encroachment of rear wheel steering on the rear undercarriage and passenger compartment space, save development costs, increase the user's riding space, and improve riding comfort.

[0044] According to the embodiment of this application, the current working condition of the vehicle can be determined based on the algorithm of the vehicle status module, that is, different modules correspond to different working conditions, and the steering angle that the rear wheels should achieve can be calculated according to the algorithm of the steering angle control module, and finally the adjustment signal is output.

[0045] Among them, such as Figure 2 As shown, the rear wheel steering angle is:

[0046] α=R·[(α0·C1,Model1), (α0·C2,Model2), (α0·C3,Model3)]

[0047] Where R is the correction coefficient, α0 is the front wheel angle calculated based on the steering wheel angle, C1 is the first preset weighting coefficient (the parking module weighting coefficient under parking conditions), C2 is the second preset weighting coefficient (the low-speed module weighting coefficient under low-speed conditions), C3 is the third preset weighting coefficient (the medium-high-speed module weighting coefficient under medium-high-speed conditions), and Model1, Model2 and Model3 are three modes corresponding to the rear wheel angle and wheel travel, respectively.

[0048] The steering angle correction factor R adjusts the rear wheel steering angle based on road and vehicle conditions. For example, when the unsprung acceleration is small and the vehicle's overall posture is stable, the steering angle correction factor is amplified to maximize the rear wheel steering angle. Conversely, when the unsprung acceleration is large or the vehicle's overall body roll is significant, the system reduces the steering angle correction factor to control the rear wheel steering angle.

[0049] The first preset weighting coefficient C1 can be set according to the maximum space allowed by the vehicle layout, with a maximum value of 1.

[0050] The second preset weighting coefficient C2 can be adjusted according to the vehicle speed.

[0051] The third preset weighting coefficient, C3, can be adjusted according to the vehicle speed.

[0052] Optionally, in one embodiment of this application, when the current working condition is a preset parking condition, the rear wheel angle is corrected by combining the front wheel angle and the current working condition of the vehicle to obtain the target angle of the rear wheel, including: acquiring the unsprung acceleration signal of the vehicle; obtaining the road surface condition of the current driving road based on the unsprung acceleration signal; and correcting the rear wheel angle based on the road surface condition to obtain the target angle.

[0053] like Figure 3 As shown, when the vehicle's current operating condition is the preset parking condition (such as a vehicle speed below 5 kph, or a vehicle speed commonly used by the user for parking), that is, when the current algorithm is determined to be the parking module's algorithm according to the vehicle status module's algorithm, the focus is on the vehicle's turning convenience at ultra-low speeds. In this mode, the unsprung acceleration sensor can be used to identify the road surface and correct the rear wheel steering angle according to the road conditions. If the road conditions are determined to be good, the rear wheel steering angle will be set to the maximum value within the design range, so that the rear wheel steering angle α can be maximized, giving full play to the characteristics of rear wheel steering in improving turning convenience, enabling the vehicle to have the smallest turning radius, thereby achieving the best passability.

[0054] Optionally, in one embodiment of this application, when the current working condition is a preset parking condition, the rear wheel angle is corrected by combining the front wheel angle and the current working condition of the vehicle to obtain the target angle of the rear wheel of the vehicle, which further includes: obtaining the suspension travel signal of the vehicle; obtaining the wheel travel of the vehicle based on the suspension travel signal; determining whether the wheel travel is greater than a first preset threshold; if the wheel travel is greater than the first preset threshold, then limiting the rear wheel angle by combining a first preset weighting coefficient, so as to adjust the maximum rear wheel angle of the vehicle to a first preset angle.

[0055] like Figure 3 As shown, in this embodiment of the application, the suspension travel signal of the vehicle can also be obtained through relevant sensors, and the wheel travel of the vehicle can be obtained based on the suspension travel signal.

[0056] Therefore, under the preset parking conditions, the embodiments of this application can impose certain restrictions on the rear wheel angle when the wheel travel is large. For example, in the relationship between the rear wheel angle and the wheel travel (Model 1), when the suspension travel sensor detects a large wheel travel value, the angle will be restricted to avoid interference risk. That is, the T1 value (first preset threshold) is small to avoid the risk of interference between the tire envelope and surrounding parts, but the restriction range is small.

[0057] The first preset threshold and the first preset angle can be set by those skilled in the art according to the actual situation, and no specific restrictions are imposed here.

[0058] Optionally, in one embodiment of this application, when the current operating condition is a preset driving condition, the rear wheel angle is corrected by combining the front wheel angle and the current operating condition of the vehicle to obtain the target angle of the rear wheel, including: acquiring the vehicle's inertial measurement unit signal; obtaining the vehicle's roll state based on the inertial measurement unit signal; and correcting the rear wheel angle by combining the vehicle's current speed, roll state, front wheel angle and road surface condition to obtain the target angle.

[0059] When the vehicle's current operating condition is the preset driving condition (such as a vehicle speed greater than 5 kph), that is, when the algorithm of the vehicle status module determines whether the current algorithm is the low-speed module or the medium-high speed module algorithm, the rear wheel steering angle is corrected.

[0060] Among them, such as Figure 4 As shown, under preset low-speed conditions, the rear wheel steering angle of this embodiment can simultaneously consider the turning convenience and driving stability of the vehicle at low speeds (such as when the vehicle speed is between 5 and 25 kph). This embodiment can use an unsprung acceleration sensor to identify the road surface and determine the vehicle's tilt state based on the IMU signal, and then correct the rear wheel steering angle by combining the road surface conditions and the vehicle tilt state.

[0061] like Figure 5As shown, under preset medium-to-high speed conditions, the embodiments of this application can ensure the vehicle's driving stability at medium-to-high speeds (such as speeds above 25 kph). The embodiments of this application can utilize an unsprung acceleration sensor to identify the road surface and determine the vehicle's tilt state based on IMU signals, then adjust the rear wheel steering angle by considering both road conditions and the vehicle's tilt state.

[0062] Optionally, in one embodiment of this application, when the current operating condition is a preset driving condition, the rear wheel angle is corrected by combining the front wheel angle and the current operating condition of the vehicle to obtain the target angle of the rear wheels. This further includes: determining whether the current vehicle speed is greater than a preset speed threshold; if the current vehicle speed is less than or equal to the preset speed threshold, then the preset driving condition is determined to be a low-speed driving condition, and the wheel travel distance is determined to be greater than a second preset threshold. If the wheel travel distance is greater than the second preset threshold, then the rear wheel angle is limited by a second preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to a second preset angle. The second preset threshold is greater than a first preset threshold, and the second preset weighting coefficient is obtained from the current vehicle speed. If the current vehicle speed is greater than the preset speed threshold, then the preset driving condition is determined to be a medium-high speed driving condition, and the wheel travel distance is determined to be greater than a third preset threshold. If the wheel travel distance is greater than the third preset threshold, then the rear wheel angle is limited by a third preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to a third preset angle. The third preset threshold is greater than the second preset threshold, and the third preset weighting coefficient is obtained from the current vehicle speed.

[0063] like Figure 4 As shown, under preset low-speed conditions, this embodiment of the application can limit the rear wheel steering angle when the wheel travel is large, avoiding the risk of interference between the tire envelope and surrounding parts. When the vehicle speed increases, C2 decreases, and when the vehicle speed decreases, C2 increases. Simultaneously, in the relationship between the rear wheel steering angle and wheel travel (Model 2), when the suspension travel sensor detects a large wheel travel value, it will limit the steering angle to avoid interference risks, and the T2 value (second preset threshold) is greater than the T1 value.

[0064] like Figure 5 As shown, under preset medium-high speed conditions, this embodiment of the application can limit the rear wheel steering angle when the wheel travel is large, avoiding the risk of interference between the tire envelope and surrounding parts. Under this condition, this embodiment of the application will strictly control C3; when the vehicle speed increases, C3 decreases, and when the vehicle speed decreases, C3 increases. Simultaneously, in the relationship between rear wheel steering angle and wheel travel (Model 3), when the suspension travel sensor detects a large wheel travel value, it will limit the steering angle to avoid interference risks, and the T3 value (third preset threshold) is greater than the T2 value.

[0065] The second and third preset thresholds can be set by those skilled in the art according to the actual situation, and no specific restrictions are imposed here.

[0066] Combination Figures 2 to 5 As shown, the working principle of the rear-wheel steering control method of the vehicle according to an embodiment of this application will be described in detail with reference to one embodiment.

[0067] like Figure 2 As shown, in this embodiment of the application, the current operating condition of the vehicle can be determined according to the algorithm of the vehicle status module, and the steering angle that the rear wheels should achieve can be calculated according to the algorithm of the steering angle control module, and finally the adjustment signal is output.

[0068] Among them, the rear wheel steering angle is:

[0069] α=R·[(α0·C1,Model1), (α0·C2,Model2), (α0·C3,Model3)]

[0070] Where R is the correction coefficient, α0 is the front wheel angle calculated based on the steering wheel angle, C1 is the first preset weighting coefficient (parking condition), C2 is the second preset weighting coefficient (low speed condition), C3 is the third preset weighting coefficient (medium and high speed condition), and Model1, Model2 and Model3 are three modes corresponding to the rear wheel angle and wheel travel, respectively.

[0071] The steering angle correction factor R adjusts the rear wheel steering angle based on road and vehicle conditions. For example, when the unsprung acceleration is small and the vehicle's overall posture is stable, the steering angle correction factor is amplified to maximize the rear wheel steering angle. Conversely, when the unsprung acceleration is large or the vehicle's overall body roll is significant, the system reduces the steering angle correction factor to control the rear wheel steering angle.

[0072] Furthermore, combined Figures 3 to 5 The embodiments of this application can divide the working conditions into three types:

[0073] Parking condition: First preset weighting coefficient C1. This coefficient can be set according to the maximum space allowed by the vehicle layout, and the maximum value is 1.

[0074] like Figure 3As shown, when the vehicle's current operating condition is the preset parking condition (such as a vehicle speed below 5 kph, or a vehicle speed commonly used by the user for parking), that is, when the current algorithm is determined to be the parking module's algorithm according to the vehicle status module's algorithm, the focus is on the vehicle's turning convenience at ultra-low speeds. In this mode, the unsprung acceleration sensor can be used to identify the road surface and correct the rear wheel steering angle according to the road conditions. If the road conditions are determined to be good, the rear wheel steering angle will be set to the maximum value within the design range, so that the rear wheel steering angle α can be maximized, giving full play to the characteristics of rear wheel steering in improving turning convenience, enabling the vehicle to have the smallest turning radius, thereby achieving the best passability.

[0075] In this embodiment, the suspension travel signal of the vehicle can also be obtained through relevant sensors, and the wheel travel of the vehicle can be obtained based on the suspension travel signal.

[0076] Therefore, under the preset parking conditions, the embodiments of this application can impose certain restrictions on the rear wheel angle when the wheel travel is large. For example, in the relationship between the rear wheel angle and the wheel travel (Model 1), when the suspension travel sensor detects a large wheel travel value, the angle will be restricted to avoid interference risk. That is, the T1 value (first preset threshold) is small to avoid the risk of interference between the tire envelope and surrounding parts, but the restriction range is small.

[0077] Low-speed operation: Second preset weighting coefficient C2, which can be adjusted according to the vehicle speed.

[0078] The rear wheel steering angle of this embodiment can simultaneously consider the turning convenience and driving stability of the vehicle at low speeds (such as when the vehicle speed is between 5 and 25 kph). This embodiment can use an unsprung acceleration sensor to identify the road surface and determine the vehicle's tilt state based on the IMU signal, and then correct the rear wheel steering angle by combining the road surface conditions and the vehicle tilt state.

[0079] This embodiment of the application can limit the rear wheel steering angle when the wheel hop travel is large, avoiding the risk of interference between the tire envelope and surrounding parts. When the vehicle speed increases, C2 decreases, and when the vehicle speed decreases, C2 increases. At the same time, in the relationship between the rear wheel steering angle and wheel hop travel (Model 2), when the suspension travel sensor detects a large wheel hop value, it will limit the steering angle to avoid the risk of interference, and the T2 value (second preset threshold) is greater than the T1 value.

[0080] Medium and high speed conditions: The third preset weighting coefficient C3 can be adjusted according to the vehicle speed.

[0081] This application embodiment can ensure vehicle stability at medium to high speeds (e.g., speeds above 25 kph). This application embodiment can utilize an unsprung acceleration sensor to identify the road surface and determine the vehicle's tilt state based on IMU signals, then adjust the rear wheel steering angle based on a combination of road conditions and vehicle tilt state.

[0082] This embodiment of the application can limit the rear wheel steering angle when the wheel hop travel is large, avoiding the risk of interference between the tire envelope and surrounding parts. Under this condition, this embodiment of the application will strictly control C3. When the vehicle speed increases, C3 decreases, and when the vehicle speed decreases, C3 increases. At the same time, in the relationship between rear wheel steering angle and wheel hop travel (Model 3), when the suspension travel sensor detects a large wheel hop value, it will limit the steering angle to avoid the risk of interference, and the T3 value (third preset threshold) is greater than the T2 value.

[0083] Based on this, the embodiments of this application can adapt rear-wheel steering schemes to existing vehicles without rear-wheel steering, without requiring changes to expensive parts such as body longitudinal beams, fenders, and rear bumpers, saving tens of millions of yuan in development costs. For vehicles that already have rear-wheel steering, the rear-wheel steering angle can be increased. Taking a certain vehicle as an example, the maximum rear-wheel steering angle of the embodiments of this application is expected to be increased from 5° to 10°, an increase of 100%, and the minimum turning diameter can be reduced by 1m.

[0084] In summary, the embodiments of this application can adjust the rear wheel steering angle according to road conditions, maximizing the advantages of rear wheel steering and improving the vehicle's steering convenience. Furthermore, since most users park or make sharp turns on paved roads with good road conditions, the embodiments of this application can greatly enhance the user's steering convenience experience.

[0085] The embodiments of this application can adjust the rear wheel steering angle in real time according to the travel of the rear wheel bounce. The rear wheel steering angle is controlled during large wheel bounces and the restriction on the rear wheel steering angle is lifted during small wheel bounces. This can avoid the risk of interference between the tire and surrounding parts and give full play to the advantages of rear wheel steering.

[0086] This application embodiment can achieve different rear wheel steering angle control according to different user scenarios by using the steering angle correction coefficient and the weighting coefficient of each module. It can logically control the rear wheel steering angle according to the user's needs for different working conditions. Under the same layout space, a larger rear wheel steering angle can be achieved, which can not only reduce the turning radius, but also improve the encroachment of the rear wheel steering on the rear undercarriage and passenger compartment space, increase the user's riding space, and improve riding comfort.

[0087] The rear-wheel steering control method for vehicles proposed in this application can determine the front and rear wheel steering angles based on the vehicle's steering angle signal. Then, by combining the front wheel steering angle with the vehicle's current operating condition, the rear wheel steering angle is corrected to obtain the target steering angle of the rear wheels. This allows the rear drive motor to adjust the internal rack position, ensuring the actual rear wheel steering angle matches the target angle. This logically controls the rear wheel steering angle to meet user needs under different operating conditions. Within the same layout space, a larger rear wheel steering angle can be achieved, reducing the turning radius and minimizing the encroachment of rear-wheel steering on the rear underbody and passenger compartment space. This saves development costs, increases passenger space, and improves ride comfort. Therefore, it solves the technical problem in related technologies where space constraints make it difficult to balance ride comfort and steering comfort, hindering the reduction of turning diameter.

[0088] Next, referring to the accompanying drawings, a rear-wheel steering control device for a vehicle according to an embodiment of this application is described.

[0089] Figure 6 This is a block diagram of the rear wheel steering control device of a vehicle according to an embodiment of this application.

[0090] like Figure 6 As shown, the rear wheel steering control device 10 of the vehicle is applied to the rear wheel steering controller, wherein the device 10 includes: a receiving module 100, a determining module 200 and a control module 300.

[0091] Specifically, the receiving module 100 is used to receive the vehicle's turning angle signal.

[0092] The determination module 200 is used to determine the front wheel steering angle and rear wheel steering angle of the vehicle based on the steering angle signal.

[0093] The control module 300 is used to combine the front wheel steering angle and the current working condition of the vehicle to correct the rear wheel steering angle, obtain the target steering angle of the vehicle's rear wheels, and control the rear drive motor of the vehicle to adjust the position of the internal rack so that the actual steering angle of the rear wheels is consistent with the target steering angle.

[0094] Optionally, in one embodiment of this application, when the current working condition is a preset parking condition, the control module 300 includes: a first acquisition unit, a second acquisition unit, and a first correction unit.

[0095] The first acquisition unit is used to acquire the unsprung acceleration signal of the vehicle.

[0096] The second acquisition unit is used to obtain the road surface condition of the current driving road of the vehicle based on the unsprung acceleration signal.

[0097] The first correction unit is used to correct the rear wheel steering angle based on the road surface conditions to obtain the target steering angle.

[0098] Optionally, in one embodiment of this application, when the current working condition is a preset parking condition, the control module 300 further includes: a third acquisition unit, a fourth acquisition unit, a first judgment unit, and a restriction unit.

[0099] The third acquisition unit is used to acquire the suspension travel signal of the vehicle.

[0100] The fourth acquisition unit is used to obtain the wheel travel of the vehicle based on the suspension travel signal.

[0101] The first judgment unit is used to determine whether the wheel jump distance is greater than the first preset threshold.

[0102] The limiting unit is used to limit the rear wheel angle by combining a first preset weighting coefficient when the wheel travel exceeds a first preset threshold, so as to adjust the maximum rear wheel angle of the vehicle to a first preset angle.

[0103] Optionally, in one embodiment of this application, when the current operating condition is a preset driving condition, the control module 300 includes: a fifth acquisition unit, a sixth acquisition unit, and a second correction unit.

[0104] The fifth acquisition unit is used to acquire signals from the vehicle's inertial measurement unit.

[0105] The sixth acquisition unit is used to obtain the vehicle's roll state based on the signal from the inertial measurement unit.

[0106] The second correction unit is used to correct the rear wheel angle by combining the vehicle's current speed, roll state, front wheel angle, and road conditions to obtain the target angle.

[0107] Optionally, in one embodiment of this application, when the current operating condition is a preset driving condition, the control module 300 further includes: a second judgment unit, a first adjustment unit, and a second adjustment unit.

[0108] The second judgment unit is used to determine whether the current vehicle speed is greater than a preset speed threshold.

[0109] The first adjustment unit is used to determine that the preset driving condition is a low-speed driving condition when the current vehicle speed is less than or equal to a preset speed threshold, so as to determine whether the wheel jump travel is greater than the second preset threshold. If the wheel jump travel is greater than the second preset threshold, the rear wheel angle is limited by the second preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to the second preset angle. The second preset threshold is greater than the first preset threshold, and the second preset weighting coefficient is obtained from the current vehicle speed.

[0110] The second adjustment unit is used to determine the preset driving condition as medium-high speed when the current vehicle speed is greater than the preset speed threshold, and to determine whether the wheel jump travel is greater than the third preset threshold. If the wheel jump travel is greater than the third preset threshold, the rear wheel angle is limited by the third preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to the third preset angle. The third preset threshold is greater than the second preset threshold, and the third preset weighting coefficient is obtained from the current vehicle speed.

[0111] It should be noted that the foregoing explanation of the rear-wheel steering control method embodiment also applies to the rear-wheel steering control device of the vehicle in this embodiment, and will not be repeated here.

[0112] The rear-wheel steering control device for a vehicle according to the embodiments of this application can determine the front and rear wheel steering angles based on the vehicle's steering angle signal. It then combines the front wheel steering angle with the vehicle's current operating conditions to correct the rear wheel steering angle, obtaining a target steering angle for the rear wheels. This allows the rear drive motor to adjust its internal rack position, ensuring the actual rear wheel steering angle matches the target angle. This logically controls the rear wheel steering angle to meet user needs under different operating conditions. Within the same layout space, a larger rear wheel steering angle can be achieved, reducing the turning radius and minimizing the encroachment of rear-wheel steering on the rear underbody and passenger compartment space. This saves development costs, increases passenger space, and improves ride comfort. Therefore, it solves the technical problem in related technologies where space constraints make it difficult to balance ride comfort and steering comfort, hindering the reduction of turning diameter.

[0113] Figure 7 A schematic diagram of the structure of a rear-wheel steering controller provided in an embodiment of this application. The rear-wheel steering controller may include:

[0114] The memory 701, the processor 702, and the computer program stored on the memory 701 and executable on the processor 702.

[0115] When the processor 702 executes the program, it implements the rear wheel steering control method for the vehicle provided in the above embodiments.

[0116] Furthermore, the rear wheel steering controller also includes:

[0117] Communication interface 703 is used for communication between memory 701 and processor 702.

[0118] The memory 701 is used to store computer programs that can run on the processor 702.

[0119] The memory 701 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0120] If the memory 701, processor 702, and communication interface 703 are implemented independently, then the communication interface 703, memory 701, and processor 702 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0121] Optionally, in a specific implementation, if the memory 701, processor 702, and communication interface 703 are integrated on a single chip, then the memory 701, processor 702, and communication interface 703 can communicate with each other through an internal interface.

[0122] The processor 702 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0123] This embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described rear-wheel steering control method for a vehicle.

[0124] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the rear-wheel steering control method for a vehicle provided in this embodiment of the invention.

[0125] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0126] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0127] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0128] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0129] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0130] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0131] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0132] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for controlling the rear-wheel steering of a vehicle, characterized in that, Applied to a rear-wheel steering controller, the method includes the following steps: Receives the vehicle's turning angle signal; The front wheel steering angle and rear wheel steering angle of the vehicle are determined based on the steering angle signal; The rear wheel angle is corrected by combining the front wheel angle and the current operating condition of the vehicle to obtain the target angle of the rear wheel, so as to control the rear drive motor of the vehicle to adjust the position of the internal rack so that the actual angle of the rear wheel is consistent with the target angle. Wherein, when the current working condition is a preset parking condition, the suspension travel signal of the vehicle is acquired, the wheel travel of the vehicle is obtained based on the suspension travel signal, and the target steering angle is obtained based on the wheel travel. When the current operating condition is a preset driving condition, the step of correcting the rear wheel angle by combining the front wheel steering angle and the vehicle's current operating condition to obtain the target steering angle of the vehicle's rear wheels includes: determining whether the current vehicle speed is greater than a preset speed threshold; if the current vehicle speed is less than or equal to the preset speed threshold, then determining that the preset driving condition is a low-speed driving condition, and determining whether the wheel jump travel is greater than a second preset threshold, wherein, if the wheel jump travel is greater than the second preset threshold, then limiting the rear wheel steering angle by combining a second preset weighting coefficient to maximize the rotation of the vehicle's rear wheels. The angle is adjusted to a second preset angle, wherein the second preset weighting coefficient is obtained from the current vehicle speed; if the current vehicle speed is greater than the preset speed threshold, the preset driving condition is determined to be a medium-high speed driving condition, so as to determine whether the wheel jump travel is greater than a third preset threshold, wherein if the wheel jump travel is greater than the third preset threshold, the rear wheel angle is limited in combination with the third preset weighting coefficient, so as to adjust the maximum rear wheel angle of the vehicle to a third preset angle, wherein the third preset threshold is greater than the second preset threshold, and the third preset weighting coefficient is obtained from the current vehicle speed.

2. The method according to claim 1, characterized in that, When the current operating condition is a preset parking condition, the step of correcting the rear wheel angle by combining the front wheel steering angle and the vehicle's current operating condition to obtain the target steering angle of the vehicle's rear wheels includes: Obtain the unsprung acceleration signal of the vehicle; The road surface condition of the current driving road of the vehicle is obtained based on the unsprung acceleration signal; The rear wheel steering angle is corrected based on the road surface condition to obtain the target steering angle.

3. The method according to claim 2, characterized in that, When the current operating condition is a preset parking condition, the step of correcting the rear wheel angle by combining the front wheel steering angle and the vehicle's current operating condition to obtain the target steering angle of the vehicle's rear wheels further includes: Determine whether the wheel jump distance is greater than a first preset threshold; If the wheel travel is greater than the first preset threshold, the rear wheel angle is limited by the first preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to the first preset angle, wherein the first preset threshold is less than or equal to the second preset threshold.

4. The method according to claim 3, characterized in that, When the current operating condition is a preset driving condition, the step of correcting the rear wheel angle by combining the front wheel steering angle and the vehicle's current operating condition to obtain the target steering angle of the vehicle's rear wheels includes: Acquire the inertial measurement unit signal of the vehicle; The vehicle's roll state is obtained based on the signals from the inertial measurement unit; The target turning angle is obtained by correcting the rear wheel turning angle by combining the vehicle's current speed, the roll state, the front wheel turning angle, and the road surface condition.

5. A rear-wheel steering control device for a vehicle, characterized in that, Applied to a rear-wheel steering controller, wherein the device includes: The receiving module is used to receive the vehicle's turning angle signal; The determining module is used to determine the front wheel steering angle and rear wheel steering angle of the vehicle based on the steering angle signal; The control module is used to combine the front wheel steering angle and the current operating condition of the vehicle to correct the rear wheel steering angle, obtain the target steering angle of the vehicle's rear wheel, and control the rear drive motor of the vehicle to adjust the position of the internal rack so that the actual steering angle of the rear wheel is consistent with the target steering angle. Wherein, when the current working condition is a preset parking condition, the control module includes: a third acquisition unit for acquiring the suspension travel signal of the vehicle; and a fourth acquisition unit for obtaining the wheel travel of the vehicle based on the suspension travel signal. When the current driving condition is a preset driving condition, the control module further includes: a second judgment unit, used to judge whether the current vehicle speed is greater than a preset speed threshold; a first adjustment unit, used to determine that the preset driving condition is a low-speed driving condition when the current vehicle speed is less than or equal to the preset speed threshold, and to judge whether the wheel travel is greater than a second preset threshold, wherein if the wheel travel is greater than the second preset threshold, the rear wheel angle is limited by a second preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to a second preset angle, wherein the second preset weighting coefficient is obtained from the current vehicle speed; and a second adjustment unit, used to determine that the preset driving condition is a medium-high speed driving condition when the current vehicle speed is greater than the preset speed threshold, and to judge whether the wheel travel is greater than a third preset threshold, wherein if the wheel travel is greater than the third preset threshold, the rear wheel angle is limited by a third preset weighting coefficient to adjust the maximum rear wheel angle of the vehicle to a third preset angle, wherein the third preset threshold is greater than the second preset threshold, and the third preset weighting coefficient is obtained from the current vehicle speed.

6. The apparatus according to claim 5, characterized in that, When the current operating condition is a preset parking condition, the control module includes: The first acquisition unit is used to acquire the unsprung acceleration signal of the vehicle; The second acquisition unit is used to obtain the road surface condition of the current driving road of the vehicle based on the unsprung acceleration signal; The correction unit is used to correct the rear wheel steering angle based on the road surface condition to obtain the target steering angle.

7. The apparatus according to claim 6, characterized in that, When the current operating condition is a preset parking condition, the control module further includes: The judgment unit is used to determine whether the wheel jump distance is greater than a first preset threshold. The limiting unit is used to limit the rear wheel angle by combining a first preset weighting coefficient when the wheel travel is greater than the first preset threshold, so as to adjust the maximum rear wheel angle of the vehicle to the first preset angle.

8. A rear-wheel steering controller, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the rear-wheel steering control method for a vehicle as described in any one of claims 1-4.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the rear-wheel steering control method for a vehicle as described in any one of claims 1-4.

Images