Vehicle, vehicle steering control system and method

Abstract

The invention provides a vehicle and a vehicle steering control system and method, and belongs to the technical field of vehicle control. The vehicle steering control method comprises the steps that the current steering angle of the vehicle is received; when the current steering angle is larger than the preset triggering angle and smaller than the maximum steering angle of the wheels, the target angle difference value is added on the basis of the numerical value of the preset triggering angle, so that a target steering angle is obtained; when the current steering angle is equal to the maximum steering angle, taking the maximum expected steering angle as a target steering angle; obtaining a target differential ratio of the vehicle driving wheel based on the target steering angle, wherein the target differential ratio is a differential ratio when the driving wheel steers to the target steering angle; the differential ratio of the drive wheel is adjusted to a target differential ratio. According to the vehicle steering control method, on the premise that the current steering angle is not increased, the actual turning radius of the vehicle is remarkably reduced, and then the driving experience of the vehicle is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and in particular to a vehicle, a vehicle steering control system and a method. Background Art

[0002] In order to ensure the passability and comfort of the vehicle, the existing vehicle structure usually sets a suspension structure with a longer stroke on the body. However, the longer stroke suspension structure will occupy the space reserved for wheel steering on both sides of the body, thereby reducing the maximum steering angle of the wheel, making it impossible to increase the steering angle of the wheel on the body at will. Limited by the small maximum steering angle of the wheel, the vehicle cannot reduce the turning radius of the vehicle by continuing to increase the wheel steering angle after the wheel turns to the maximum steering angle, which makes the turning radius of the vehicle larger and difficult to reduce, making it more difficult for the vehicle to turn and turn around in a limited space, and having a negative impact on the driving experience of the vehicle driver.

[0003] Therefore, it is necessary to provide a vehicle, a vehicle steering control system and a method, which can significantly reduce the vehicle turning radius without increasing the wheel steering angle, thereby solving the above-mentioned technical problems. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention provides a vehicle, a vehicle steering control system and a method to improve the technical problem that the existing vehicle steering control system is limited by the maximum steering angle of the wheels, resulting in a large turning radius of the vehicle that cannot be reduced.

[0005] To achieve the above-mentioned object and other related objects, the present invention provides a vehicle steering control method in a first aspect, the vehicle steering control method comprising:

[0006] Receive the vehicle's current steering angle;

[0007] When the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, the target angle difference is added to the value of the preset trigger angle to obtain the target steering angle; wherein the target angle difference is obtained based on the preset maximum expected angle, the maximum steering angle, the preset trigger angle and the current steering angle, the maximum expected steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle;

[0008] When the current steering angle is equal to the maximum steering angle, the maximum expected steering angle is used as the target steering angle;

[0009] Obtaining a target differential speed ratio of the vehicle driving wheels based on the target steering angle, the target differential speed ratio being the differential speed ratio when the driving wheels are turned to the target steering angle;

[0010] Adjust the differential ratio of the drive wheels to the target differential ratio.

[0011] In an example of the present invention, adding a target angle difference to a preset trigger angle value to obtain a target steering angle includes:

[0012] The difference between the maximum expected steering angle and the preset trigger angle is used as the first angle difference, and the difference between the maximum steering angle and the preset trigger angle is used as the second angle difference;

[0013] The ratio of the first angle difference to the second angle difference is used as a proportional parameter;

[0014] The product of the proportional parameter and the difference between the current steering angle and the preset trigger angle is taken as the target angle difference;

[0015] The sum of the difference between the preset trigger angle and the target angle is used as the target steering angle.

[0016] In an example of the present invention, obtaining a target differential ratio of vehicle drive wheels based on a target steering angle includes: obtaining the target differential ratio based on a vehicle wheelbase, a vehicle track and a target steering angle.

[0017] In an example of the present invention, obtaining a target differential ratio based on a vehicle wheelbase, a vehicle track width, and a target steering angle includes:

[0018] The driving wheels are the front wheels and / or the rear wheels; the target differential ratio of the rear wheels is V 1 / V 2 =LcotΦ T / (LcotΦ T +M), the target differential ratio of the front wheels is Among them, V 1 is the inner wheel speed of the rear wheel, V 2 is the outer wheel speed of the rear wheel, V 3 is the inner wheel speed of the front wheel, V 4 is the outer wheel speed of the front wheel, L is the vehicle wheelbase, M is the vehicle track, Φ T is the target steering angle, the inner wheel is the wheel relatively close to the steering center of the vehicle among the driving wheels, and the outer wheel is the wheel relatively far from the steering center of the vehicle among the driving wheels.

[0019] In an example of the present invention, adjusting the differential speed ratio of the driving wheels to a target differential speed ratio includes:

[0020] Adjust the rotation speed of the outer wheel and / or the inner wheel among the driving wheels so that the differential ratio of the driving wheels is equal to the target differential ratio; wherein the inner wheel is the wheel among the driving wheels that is relatively close to the steering center of the vehicle, and the outer wheel is the wheel among the driving wheels that is relatively far from the steering center of the vehicle.

[0021] In one example of the present invention, the maximum desired steering angle is 90°.

[0022] In one example of the present invention, the vehicle steering control method also includes, when the current steering angle is greater than a preset trigger angle, increasing the torque applied by the power system to the drive wheel to K times the original torque, where K is the ratio of the target steering angle to the current steering angle.

[0023] In a second aspect, the present invention provides a vehicle steering control system, which includes a first sensor, a brake, a second sensor and a controller.

[0024] The first sensor is used to detect the current steering angle of the vehicle; the brake is set on the driving wheel; the second sensor is used to detect the rotation speed of the driving wheel; the controller is electrically connected to the first sensor, the second sensor and the brake; the controller obtains the corresponding target steering angle based on the current steering angle; the controller obtains the target differential ratio of the driving wheel based on the target steering angle, and the target differential ratio is the differential ratio when the driving wheel is turned to the target steering angle; the controller adjusts the differential ratio of the driving wheel to the target differential ratio;

[0025] Among them, when the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, the controller uses the sum of the target angle difference and the preset trigger angle as the target steering angle, and the target angle difference is obtained based on the preset maximum expected angle, maximum steering angle, preset trigger angle and current steering angle, the maximum expected steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle; when the current steering angle is equal to the maximum steering angle, the controller uses the maximum expected steering angle as the target steering angle.

[0026] In one example of the present invention, the controller uses brakes to adjust the rotation speed of the outer wheel and / or inner wheel of the driving wheel so that the differential ratio of the driving wheel is equal to the target differential ratio; wherein the inner wheel is the wheel among the driving wheels that is relatively close to the steering center of the vehicle, and the outer wheel is the wheel among the driving wheels that is relatively far from the steering center of the vehicle.

[0027] In one example of the present invention, the vehicle steering control system also includes a power system, the power system includes a drive motor and a drive shaft, the drive motor is arranged on the vehicle body, the drive shaft is transmission-connected to the drive motor, the drive wheels are located on both sides of the vehicle body, and the drive wheels are connected to the drive shaft; when the controller detects that the current steering angle is greater than the preset trigger angle, the controller drives the power system to increase the torque applied to the drive wheel to K times the original torque, where K is the ratio of the target steering angle to the current steering angle.

[0028] The present invention provides a vehicle in a third aspect. The vehicle includes a vehicle body, drive wheels, a first sensor, a brake, a second sensor, and a controller.

[0029] The driving wheels are arranged on both sides of the vehicle body; the first sensor is used to detect the current steering angle of the vehicle; the brake is arranged on the driving wheel; the second sensor is used to detect the rotation speed of the driving wheel; the controller is electrically connected with the first sensor, the second sensor and the brake; the controller obtains the corresponding target steering angle based on the current steering angle; the controller obtains the target differential ratio of the driving wheels based on the target steering angle, and the target differential ratio is the differential ratio when the driving wheels are turned to the target steering angle; the controller adjusts the differential ratio of the driving wheels to the target differential ratio;

[0030] Among them, when the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, the controller uses the sum of the target angle difference and the preset trigger angle as the target steering angle, and the target angle difference is obtained based on the preset maximum expected angle, maximum steering angle, preset trigger angle and current steering angle, the maximum expected steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle; when the current steering angle is equal to the maximum steering angle, the controller uses the maximum expected steering angle as the target steering angle.

[0031] The vehicle steering control method of the present invention first responds to the current steering angle according to a preset rule when the current steering angle of the vehicle is greater than a preset trigger angle, and obtains a target steering angle for the vehicle to complete the steering with a smaller turning radius; then adjusts the differential ratio of the drive wheels on the vehicle to the target differential ratio when turning to the target steering angle, thereby significantly reducing the actual turning radius of the vehicle without increasing the current steering angle, thereby effectively improving the driving experience of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A flow chart of a vehicle steering control method according to an embodiment of the present invention;

[0034] Figure 2 This is a flow chart of step S12 in one embodiment of the present invention;

[0035] Figure 3 It is a schematic diagram of the structure of a vehicle in a left turning state according to an embodiment of the present invention;

[0036] Figure 4 A schematic diagram of the structure of a vehicle steering control system in one embodiment of the present invention;

[0037] Figure 5A flow chart of a steering control method implemented by a vehicle steering control system in one embodiment of the present invention;

[0038] Figure 6 A schematic diagram of the structure of a vehicle steering control system in another embodiment of the present invention;

[0039] Figure 7 A flow chart of a steering control method implemented by a vehicle steering control system in another embodiment of the present invention;

[0040] Figure 8 A schematic diagram of the structure of a vehicle steering control system in another embodiment of the present invention;

[0041] Fig. 9 A flow chart of a steering control method implemented by a vehicle steering control system in another embodiment of the present invention;

[0042] Fig.10 FIG. 1 is a schematic diagram of the structure of a vehicle in one embodiment of the present invention.

[0043] Component number description

[0044] 100, vehicle body; 910, power system; 911, drive motor; 912, drive shaft; 920, rear wheels; 921, left rear wheel; 922, right rear wheel; 930, front wheels; 931, left front wheel; 932, right front wheel; 940, first sensor; 950, second sensor; 960, brake; 970, controller. DETAILED DESCRIPTION

[0045] The following is an explanation of the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the features in the following embodiments and the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are usually carried out under conventional conditions or according to the conditions recommended by the manufacturers.

[0046] When numerical ranges are given in the embodiments, it should be understood that unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention are familiar to those skilled in the art and the description of the present invention, and any method, device and material of the prior art similar or equivalent to the method, device and material in the embodiments of the present invention can also be used to implement the present invention.

[0047] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" etc. used in this specification are only for the convenience of description and are not intended to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be regarded as the scope of implementation of the present invention.

[0048] See also Figures 1 to 10 The present invention provides a vehicle, a vehicle steering control system and a method, which can respond to the increasing trend of the current steering angle according to preset rules when the current steering angle is greater than the preset trigger angle, and obtain the target steering angle for the vehicle to complete the steering with a smaller turning radius; then obtain the target differential ratio when the driving wheel is turned to the target steering angle based on the target steering angle; finally, adjust the differential ratio of the driving wheels on the vehicle to the target differential ratio. The vehicle steering control method responds to the current steering angle to obtain the driver's driving intention to reduce the turning radius without increasing the current steering angle, and reduces the actual turning radius of the vehicle by adjusting the differential ratio of the driving wheels, thereby effectively improving the flexibility of vehicle driving and improving the driving experience of the vehicle.

[0049] See also Figure 1 In a first aspect, the present invention provides a vehicle steering control method, the vehicle steering control method comprising the following steps:

[0050] S11, receiving the current steering angle of the vehicle;

[0051] S12. When the current steering angle is greater than a preset trigger angle and less than a maximum steering angle of the wheel, a target angle difference is added to the value of the preset trigger angle to obtain a target steering angle; wherein the target angle difference is obtained based on a preset maximum desired angle, a maximum steering angle, a preset trigger angle and a current steering angle, the maximum desired steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle;

[0052] S13, when the current steering angle is equal to the maximum steering angle, the maximum expected steering angle is used as the target steering angle;

[0053] S14, obtaining a target differential speed ratio of the vehicle driving wheels based on the target steering angle, the target differential speed ratio being the differential speed ratio when the driving wheels are turned to the target steering angle;

[0054] S15: Adjust the differential speed ratio of the driving wheels to a target differential speed ratio.

[0055] It should be noted that the execution order of step S12 and step S13 is not specifically limited in the present application. In some embodiments, at least one of step S12 and step S13 is an optional step. For example, the vehicle steering control method may execute step S12 when the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, and directly execute step S14 after executing step S12 without executing step S13; for another example, the vehicle steering control method may execute step S13 when the current steering angle is equal to the maximum steering angle without executing step S12.

[0056] Since there is a steering wheel in the wheel that is connected to the steering wheel, such as the front wheel 930 of the vehicle, the steering wheel is controlled by the steering wheel to rotate to the steering angle to guide the vehicle to turn according to the steering angle during the subsequent travel process. Therefore, in some embodiments, in step S11, the steering angle of the steering wheel is obtained in real time, and the steering angle of the steering wheel is used as the current steering angle of the vehicle.

[0057] In step S12, when the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, the current steering angle is responded to according to the preset rule, and the target steering angle at which the vehicle is expected to complete the steering with a smaller turning radius is obtained accordingly, so that the differential ratio of the drive wheels is adjusted according to the target steering angle in the subsequent steps, thereby reducing the actual turning radius of the vehicle. The preset trigger angle can be set to any angle value between 0° and the maximum steering angle; illustratively, the preset trigger angle is set to any angle value between 0° and 90°, for example, the preset trigger angle can be set to 60°.

[0058] Among them, the target steering angle obtained in step S12 should be greater than the current steering angle, the target steering angle is the sum of the preset trigger angle and the target angle difference, the target angle difference is obtained based on the preset maximum expected angle, maximum steering angle, preset trigger angle and current steering angle, the obtained target angle difference is proportional to the difference between the current steering angle and the preset trigger angle, and the preset proportional parameter is obtained based on the preset maximum expected angle, maximum steering angle and preset trigger angle. The maximum expected angle of the wheel should be greater than the maximum steering angle. For example, in some embodiments, the maximum expected angle is 90°.

[0059] Specifically, Figure 2 As shown, in some embodiments, step S12 includes the following steps:

[0060] S121, taking the difference between the maximum expected steering angle and the preset trigger angle as the first angle difference, and taking the difference between the maximum steering angle and the preset trigger angle as the second angle difference;

[0061] In step S121, the first angle difference ΔΦ 1 is ΔΦ 1 =Φ max1 -Φ 0 , the second angle difference ΔΦ 2 is ΔΦ 1 =Φ max0 -Φ 0 , where Φ max1 is the maximum desired steering angle, Φ max0 is the maximum steering angle, Φ 0 The preset trigger angle.

[0062] S122, taking the ratio of the first angle difference to the second angle difference as a proportional parameter;

[0063] In step S122, the proportional parameter is the ratio of the first angle difference to the second angle difference, that is, the proportional parameter D is

[0064] S123, taking the product of the proportional parameter and the difference between the current steering angle and the preset trigger angle as the target angle difference;

[0065] In step S123, the target angle difference is the product of the proportional parameter and the difference between the current steering angle and the preset trigger angle, that is, the target angle difference ΔΦ is Φ is the current steering angle.

[0066] S124: taking the sum of the difference between the preset trigger angle and the target angle as the target steering angle.

[0067] In step S124, the target steering angle is the sum of the difference between the preset trigger angle and the target angle, that is, the target steering angle Φ T for Obtained target steering angle Φ T According to the preset parameters, the current steering angle Φ changes, at the preset trigger angle Φ 0 Based on the increase in the current steering angle Φ and the preset trigger angle Φ 0 The target angle difference ΔΦ of the difference between the two is proportional to the proportional parameter D. This enables step S12 to respond to the change of the current steering angle Φ and obtain a steering angle greater than the current steering angle Φ and less than the maximum desired steering angle Φ. max1 The target steering angle Φ T , so that the vehicle can respond to changes in the current steering angle Φ and adjust the vehicle's turning radius accordingly.

[0068] In step S13, when the current steering angle is equal to the maximum steering angle, that is, when the steering wheel rotates to the maximum steering angle and cannot continue to increase, the maximum expected steering angle is used as the target steering angle, so that the differential ratio of the driving wheels is adjusted according to the target steering angle in the subsequent steps, so that the actual turning radius of the vehicle is minimized. For example, in one example, the maximum expected steering angle is 90°, and when the current steering angle rotates to the maximum steering angle, the differential ratio of the driving wheels is adjusted with 90° as the target steering angle, so as to reduce the turning radius of the vehicle to the minimum.

[0069] In step S14, a target differential speed ratio of the vehicle driving wheels is obtained based on the target steering angle, and the target differential speed ratio is the differential speed ratio when the driving wheels are turned to the target steering angle. In some implementations, in step S14, a target differential speed ratio among the driving wheels is obtained based on the vehicle wheelbase, the vehicle track and the target steering angle, and the target differential speed ratio is the wheel speed ratio between the outer wheel and the inner wheel among the driving wheels, and the driving wheels may be the front wheels 930, the rear wheels 920, or the front wheels 930 and the rear wheels 920, the inner wheels of the driving wheels are the wheels among the driving wheels that are relatively close to the steering center of the vehicle, and the outer wheels of the driving wheels are the wheels among the driving wheels that are relatively far from the steering center of the vehicle.

[0070] Specific as Figure 3 As shown, when the vehicle turns around the steering center O at the current steering angle Φ, the differential ratio of the rear wheels 920 is V 1 / V 2 =LcotΦ / (LcotΦ+M), the differential ratio of the front wheel 930 is Among them, V 1 is the speed of the inner wheel of the rear wheel 920, V 2 is the rotation speed of the outer wheel of the rear wheel 920, V 3 is the speed of the inner wheel of the front wheel 930, V 4 is the rotation speed of the outer wheel in the front wheel 930, L is the vehicle wheelbase, M is the vehicle track, Φ is the current steering angle, the inner wheel is the wheel relatively close to the steering center among the front wheel 930 or the rear wheel 920, and the outer wheel is the wheel relatively far from the steering center among the front wheel 930 or the rear wheel 920, for example Figure 3 As shown, when the vehicle turns left, the left front wheel 931 of the front wheels 930 is the inner wheel, and the right front wheel 932 is the outer wheel; the left rear wheel 921 of the rear wheels 920 is the inner wheel, and the right rear wheel 922 is the outer wheel. Based on the above relationship, the target differential ratio when the rear wheel 920 is used as a driving wheel is determined to be V 1 / V 2 =LcotΦ T / (LcotΦ T +M), the target differential ratio when the front wheels 930 are used as driving wheels is determined as Φ T is the target steering angle.

[0071] In step S15, the differential speed ratio of the vehicle driving wheels is adjusted to the target differential speed ratio, thereby reducing the turning radius of the vehicle turning without increasing the current steering angle. Specifically, in step S15, the speed of the outer wheel and / or the inner wheel of the driving wheels is adjusted so that the differential speed ratio of the driving wheels is equal to the target differential speed ratio. In some embodiments, in step S15, the speed of the outer wheel and / or the inner wheel of the driving wheels is adjusted by the brake 960 provided on the driving wheels so that the differential speed ratio of the driving wheels is equal to the target differential speed ratio.

[0072] When the current steering angle is greater than the preset trigger angle, in step S15, the rotation speed of the outer wheel and / or the inner wheel of the driving wheel is adjusted by braking through the brake 960 so that the differential ratio of the driving wheel is equal to the target differential ratio. However, during the adjustment process, due to the braking effect of the brake 960 on the driving wheel, the vehicle's steering power will be lost. In order to make up for the power lost during the steering process, in some embodiments, when the current steering angle is greater than the preset trigger angle, in step S15, in addition to adjusting the driving wheel differential ratio through the brake 960, the torque applied by the power system 910 to the driving wheel is correspondingly increased, so that the torque applied by the power system 910 to the driving wheel is K times the original torque, so as to make up for the vehicle power loss caused by the braking effect; wherein K is the ratio of the target steering angle to the current steering angle, that is, K=Φ T / Φ.

[0073] In addition, in some embodiments, when the current steering angle is less than a preset trigger angle, it is determined that the driver has no intention of further reducing the turning radius, and the vehicle uses the current steering angle as the target steering angle, and in subsequent steps adjusts the differential ratio of the drive wheels based on the target steering angle.

[0074] See also Figures 4 to 10 In a second aspect, the present invention also provides a vehicle steering control system, which is incorporated into a vehicle having a steering control function, such as a sedan, an all-terrain mountain vehicle, etc. The vehicle steering control system is operably connected to a vehicle body 100, various components, and an electronic control system.

[0075] See also Figures 4 to 10 The vehicle steering control system includes a first sensor 940, a brake 960, a second sensor 950 and a controller 970.

[0076] The first sensor 940 is used to detect the current steering angle of the vehicle. The first sensor 940 is set at a conventional position for detecting the steering direction of the steering wheel. For example, the first sensor 940 can be set on the steering wheel of the vehicle, the steering column connected to the steering wheel, or the steering wheel controlled by the steering wheel. The brake 960 is installed on the driving wheel of the vehicle and fixedly connected to the body 100. The brake 960 brakes and adjusts the rotation speed of the left wheel and the right wheel of the driving wheel respectively; wherein the driving wheel of the vehicle is the wheel connected to the power system 910 by transmission. The second sensor 950 is used to detect the rotation speed of the driving wheel. The second sensor 950 is set on the driving shaft 912 fixedly connected to the driving wheel. For example, the second sensor 950 is respectively set on the driving shaft 912 connected to the left wheel and the right wheel of the driving wheel. The second sensor 950 can detect the rotation speed of the left wheel and the right wheel of the driving wheel respectively.

[0077] The controller 970 is electrically connected to the first sensor 940, the second sensor 950 and the brake 960. The controller 970 can be configured to execute the control algorithm in series or in parallel. Specifically, the controller 970 obtains the corresponding target steering angle according to a preset rule based on the current steering angle fed back by the first sensor 940; then, the controller 970 obtains the target differential ratio of the vehicle driving wheels based on the target steering angle, and the target differential ratio is the differential ratio when the driving wheels are turned to the target steering angle; finally, the controller 970 adjusts the differential ratio between the outer wheel speed and the inner wheel speed of the driving wheels based on the real-time feedback of the rotation speed of the inner wheel and the outer wheel of the driving wheels by the second sensor 950, so as to adjust the differential ratio of the driving wheels to the target differential ratio, thereby reducing the turning radius of the vehicle's subsequent travel without increasing the current steering angle.

[0078] When the controller 970 detects that the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, the controller 970 uses the sum of the target angle difference and the preset trigger angle as the target steering angle, and adjusts the differential ratio of the drive wheels according to the target steering angle, thereby reducing the actual turning radius of the vehicle; the target angle difference is obtained based on the preset maximum expected angle, the maximum steering angle, the preset trigger angle and the current steering angle, the target steering angle is greater than the current steering angle and less than the maximum expected angle, the maximum expected steering angle is greater than the maximum steering angle, for example, in one example, the maximum expected steering angle is 90°.

[0079] Among them, the target steering angle is the preset trigger angle Φ 0 The sum of the difference ΔΦ from the target angle is the target steering angle Φ T for Φ max1 is the maximum desired steering angle, Φ max0 is the maximum steering angle, Φ 0is the preset trigger angle, and Φ is the current steering angle.

[0080] When the controller 970 detects that the current steering angle is equal to the maximum steering angle, the controller 970 uses the maximum desired steering angle as the target steering angle and adjusts the differential ratio of the drive wheels according to the target steering angle so that the actual turning radius of the vehicle is minimized.

[0081] In addition, in one embodiment, when the controller 970 detects that the current steering angle is less than a preset trigger angle, it determines that the driver has no intention of further reducing the turning radius. The controller 970 uses the current steering angle as the target steering angle and adjusts the differential ratio of the drive wheels based on the target steering angle so that the vehicle turns and moves according to the current steering angle.

[0082] See also Figure 4 , Figure 6 and Figure 8 In some embodiments, the vehicle steering control system further includes a power system 910, the power system 910 includes a drive motor 911 and a drive shaft 912, the drive motor 911 is disposed on the vehicle body 100, the drive shaft 912 is in transmission connection with the drive motor 911, and the drive wheels are located on both sides of the vehicle body 100 and connected to the drive shaft 912. When the controller 970 detects that the current steering angle is greater than the preset trigger angle, the controller 970 not only adjusts the differential ratio of the drive wheels to the target differential ratio through the brake 960, but also controls to increase the torque applied by the power system 910 on the drive wheels, that is, to increase the torque applied by the drive motor 911 on the drive wheels through the drive shaft 912, so that the torque applied by the power system 910 on the drive wheels is increased to K times the original torque to compensate for the vehicle power loss caused by the braking effect; wherein K is the ratio of the target steering angle to the current steering angle, that is, K=Φ T / Φ.

[0083] See also Figure 4 , Figure 6 and Figure 8 In some embodiments, the controller 970 uses the brake 960 to independently adjust the rotation speed of the outer wheel and / or the inner wheel of the driving wheels so that the differential ratio of the driving wheels is equal to the target differential ratio.

[0084] See also Figure 4 , Figure 6 and Figure 8 In some embodiments, the driving wheel may be the front wheel 930, the rear wheel 920, or both the front wheel 930 and the rear wheel 920. The target differential ratio when the rear wheel 920 is used as the driving wheel is determined as V 1 / V 2 =LcotΦ T / (LcotΦ T+M), the target differential ratio when the front wheels 930 are used as driving wheels is determined as V 1 is the speed of the inner wheel of the rear wheel 920, V 2 is the rotation speed of the outer wheel of the rear wheel 920, V 3 is the speed of the inner wheel of the front wheel 930, V 4 is the rotation speed of the outer wheel of the front wheel 930, L is the vehicle wheelbase, M is the vehicle track, Φ T is the target steering angle.

[0085] like Figure 4 and Figure 5 As shown, in one embodiment, when the driving wheel of the vehicle is the rear wheel 920, the vehicle steering control system performs the following steering control method, which includes:

[0086] S21, the controller 970 obtains the current steering angle collected by the first sensor 940;

[0087] S22, when the controller 970 detects that the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, the controller 970 obtains a target angle difference based on the maximum expected angle, the maximum steering angle, the preset trigger angle and the current steering angle, and adds the target angle difference to the value of the preset trigger angle to obtain a target steering angle; wherein the maximum expected steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle and less than the maximum expected steering angle;

[0088] S23, when the controller 970 detects that the current steering angle is equal to the maximum steering angle, the controller 970 uses the maximum desired steering angle as the target steering angle;

[0089] S24, the controller 970 obtains the target differential ratio of the rear wheels 920 based on the target steering angle, the target differential ratio being the differential ratio when the rear wheels 920 are turned to the target steering angle; the target differential ratio is V 1 / V 2 =LcotΦ T / (LcotΦ T +M), V 1 is the speed of the inner wheel of the rear wheel 920, V 2 is the rotation speed of the outer wheel of the rear wheel 920, L is the vehicle wheelbase, M is the vehicle track, Φ T is the target steering angle;

[0090] S25. The controller 970 uses the brake 960 to adjust the wheel speed of the inner wheel and / or the outer wheel of the rear wheel 920 so that the differential ratio of the rear wheel 920 is equal to the target differential ratio.

[0091] like Figure 6and Figure 7 As shown, in another embodiment, when the driving wheel of the vehicle is the front wheel 930, the vehicle steering control system performs the following steering control method, which includes:

[0092] S31, the controller 970 obtains the current steering angle collected by the first sensor 940;

[0093] S32, when the controller 970 detects that the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, the controller 970 obtains a target angle difference based on the maximum desired angle, the maximum steering angle, the preset trigger angle and the current steering angle, and adds the target angle difference to the value of the preset trigger angle to obtain a target steering angle; wherein the maximum desired steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle and less than the maximum desired steering angle;

[0094] S33, when the controller 970 detects that the current steering angle is equal to the maximum steering angle, the controller 970 uses the maximum desired steering angle as the target steering angle;

[0095] S34, the controller 970 obtains the target differential ratio of the front wheels 930 based on the target steering angle, the target differential ratio being the differential ratio when the front wheels 930 are turned to the target steering angle; the target differential ratio is V 3 is the speed of the inner wheel of the front wheel 930, V 4 is the rotation speed of the outer wheel of the front wheel 930, L is the vehicle wheelbase, M is the vehicle track, Φ T is the target steering angle;

[0096] S35. The controller 970 uses the brake 960 to adjust the wheel speed of the inner wheel and / or the outer wheel of the front wheels 930 so that the differential ratio of the front wheels 930 is equal to the target differential ratio.

[0097] like Figure 8 and Fig. 9 As shown, in another embodiment, when the driving wheels of the vehicle are the front wheels 930 and the rear wheels 920, the vehicle steering control system performs the following steering control method, which includes:

[0098] S41, the controller 970 obtains the current steering angle collected by the first sensor 940;

[0099] S42, when the controller 970 detects that the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, the controller 970 obtains a target angle difference based on the maximum desired angle, the maximum steering angle, the preset trigger angle and the current steering angle, and adds the target angle difference to the value of the preset trigger angle to obtain a target steering angle; wherein the maximum desired steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle and less than the maximum desired steering angle;

[0100] S43, when the controller 970 detects that the current steering angle is equal to the maximum steering angle, the controller 970 uses the maximum desired steering angle as the target steering angle;

[0101] S44: The controller 970 obtains the target differential ratio of the front wheels 930 and the target differential ratio of the rear wheels 920 based on the target steering angle; the target differential ratio of the rear wheels 920 is V 1 / V 2 =LcotΦ T / (LcotΦ T +M), the target differential ratio of the front wheels 930 is V 1 is the speed of the inner wheel of the rear wheel 920, V 2 is the rotation speed of the outer wheel of the rear wheel 920, V 3 is the speed of the inner wheel of the front wheel 930, V 4 is the rotation speed of the outer wheel of the front wheel 930, L is the vehicle wheelbase, M is the vehicle track, Φ T is the target steering angle;

[0102] S45: The controller 970 uses the brake 960 to adjust the differential ratios of the front wheels 930 and the rear wheels 920 respectively, so that the differential ratio of the rear wheels 920 is equal to the target differential ratio V of the rear wheels 920. 1 / V 2 , and makes the differential ratio of the front wheels 930 equal to the target differential ratio V of the front wheels 930 3 / V 4 .

[0103] See also Figure 4 , Figure 6 , Figure 8 and Fig.10 In a third aspect, the present invention further provides a vehicle, which includes a vehicle body 100, driving wheels, a first sensor 940, a second sensor 950, a brake 960 and a controller 970.

[0104] The driving wheels are arranged on both sides of the vehicle body 100. The driving wheels are wheels connected to the power system 910 by transmission. The driving wheels can be arranged as the rear wheels 920 or the front wheels 930, or can be arranged as the rear wheels 920 and the front wheels 930 at the same time. The first sensor 940 is used to detect the current steering angle of the vehicle. The first sensor 940 is arranged at a conventional position for detecting the steering direction of the steering wheel. For example, the first sensor 940 can be arranged on the steering wheel of the vehicle, the steering column connected to the steering wheel, or the steering wheel controlled by the steering wheel. The brake 960 is installed on the driving wheel of the vehicle and fixedly connected to the vehicle body 100. The brake 960 brakes and adjusts the rotation speed of the left wheel and the right wheel of the driving wheel respectively. The second sensor 950 is used to detect the rotation speed of the driving wheel. The second sensor 950 is arranged on the driving shaft 912 fixedly connected to the driving wheel. For example, the second sensor 950 is respectively arranged on the driving shaft 912 connected to the left wheel and the right wheel of the driving wheel. The second sensor 950 can detect the rotation speed of the left wheel and the right wheel of the driving wheel respectively.

[0105] The controller 970 is electrically connected to the first sensor 940, the second sensor 950 and the brake 960. The controller 970 can be configured to execute the control algorithm in series or in parallel. Specifically, the controller 970 obtains the corresponding target steering angle according to a preset rule based on the current steering angle fed back by the first sensor 940; then, the controller 970 obtains the target differential ratio of the vehicle driving wheels based on the target steering angle, and the target differential ratio is the differential ratio when the driving wheels are turned to the target steering angle; finally, the controller 970 adjusts the differential ratio between the outer wheel speed and the inner wheel speed of the driving wheels based on the real-time feedback of the rotation speed of the inner wheel and the outer wheel of the driving wheels by the second sensor 950, so as to adjust the differential ratio of the driving wheels to the target differential ratio, thereby reducing the turning radius of the vehicle's subsequent travel without increasing the current steering angle.

[0106] When the controller 970 detects that the current steering angle is greater than the preset trigger angle and less than the maximum steering angle of the wheel, the controller 970 uses the sum of the target angle difference and the preset trigger angle as the target steering angle, and adjusts the differential ratio of the drive wheels according to the target steering angle, thereby reducing the actual turning radius of the vehicle; the target angle difference is obtained based on the preset maximum expected angle, the maximum steering angle, the preset trigger angle and the current steering angle, the target steering angle is greater than the current steering angle and less than the maximum expected angle, the maximum expected steering angle is greater than the maximum steering angle, for example, in one example, the maximum expected steering angle is 90°.

[0107] When the controller 970 detects that the current steering angle is equal to the maximum steering angle, the controller 970 uses the maximum desired steering angle as the target steering angle and adjusts the differential ratio of the drive wheels according to the target steering angle so that the actual turning radius of the vehicle is minimized.

[0108] In summary, the vehicle steering control method of the present invention, when the current steering angle of the vehicle is greater than the preset trigger angle, first responds to the current steering angle according to the preset rules to obtain the target steering angle for the vehicle to complete the steering with a smaller turning radius; then adjusts the differential ratio of the driving wheels on the vehicle to the target differential ratio when turning to the target steering angle, thereby significantly reducing the actual turning radius of the vehicle without increasing the current steering angle, thereby effectively improving the driving experience of the vehicle. Therefore, the present invention effectively overcomes some practical problems in the prior art and has high utilization value and use significance.

[0109] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

[0110] It should be understood that, although each operation step is indicated by arrows in the flowchart of the embodiment of the present application, the implementation order of these steps is not limited to the order indicated by the arrows. Unless clearly stated herein, in some implementation scenarios of the embodiment of the present application, the implementation steps in each flowchart can be performed in other orders according to demand. In addition, some or all of the steps in each flowchart may include multiple sub-steps or multiple stages based on actual implementation scenarios. Some or all of these sub-steps or stages may be executed at the same time, and each sub-step or stage in these sub-steps or stages may also be executed at different times respectively. In different scenarios of execution time, the execution order of these sub-steps or stages may be flexibly configured according to demand, and the embodiment of the present application does not limit this.

Claims

1. A vehicle steering control method, characterized in that: include: Receive the vehicle's current steering angle; When the current steering angle is greater than a preset trigger angle and less than a maximum steering angle of the wheel, a target angle difference is added to the value of the preset trigger angle to obtain a target steering angle; wherein the target angle difference is obtained based on a preset maximum expected angle, the maximum steering angle, the preset trigger angle and the current steering angle, the maximum expected steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle; When the current steering angle is equal to the maximum steering angle, the maximum expected steering angle is used as the target steering angle; Acquire a target differential speed ratio of the vehicle driving wheels based on the target steering angle, the target differential speed ratio being the differential speed ratio when the driving wheels are turned to the target steering angle; Adjust the differential ratio of the drive wheels to the target differential ratio.

2. The vehicle steering control method according to claim 1, characterized in that: Adding a target angle difference to the value of the preset trigger angle to obtain a target steering angle includes: The difference between the maximum expected steering angle and the preset trigger angle is used as a first angle difference, and the difference between the maximum steering angle and the preset trigger angle is used as a second angle difference; Taking the ratio of the first angle difference to the second angle difference as a proportional parameter; taking the product of the proportional parameter and the difference between the current steering angle and the preset trigger angle as the target angle difference; The sum of the difference between the preset trigger angle and the target angle is used as the target steering angle.

3. The vehicle steering control method according to claim 1, characterized in that: Obtaining a target differential ratio of the vehicle drive wheels based on the target steering angle includes: The target differential ratio is obtained based on the vehicle wheelbase, the vehicle track width and the target steering angle.

4. The vehicle steering control method according to claim 3, characterized in that: The target differential ratio is obtained based on the vehicle wheelbase, the vehicle track and the target steering angle, including: The driving wheels are the front wheels and / or the rear wheels; the target differential ratio of the rear wheels is V1 / V2=LcotΦ T / (LcotΦ T +M), the target differential ratio of the front wheels is Wherein, V1 is the inner wheel speed of the rear wheel, V2 is the outer wheel speed of the rear wheel, V3 is the inner wheel speed of the front wheel, V4 is the outer wheel speed of the front wheel, L is the vehicle wheelbase, M is the vehicle track, Φ T is the target steering angle, the inner wheel is a wheel among the driving wheels that is relatively close to the steering center of the vehicle, and the outer wheel is a wheel among the driving wheels that is relatively far from the steering center of the vehicle.

5. The vehicle steering control method according to claim 1, characterized in that: Adjust the differential ratio of the driving wheels to the target differential ratio, including: The rotation speed of the outer wheel and / or the inner wheel among the driving wheels is adjusted so that the differential ratio of the driving wheels is equal to the target differential ratio; wherein the inner wheel is a wheel among the driving wheels that is relatively close to the steering center of the vehicle, and the outer wheel is a wheel among the driving wheels that is relatively far from the steering center of the vehicle.

6. The vehicle steering control method according to claim 1, characterized in that: The maximum desired steering angle is 90°.

7. The vehicle steering control method according to claim 1, characterized in that: Also includes: When the current steering angle is less than the preset trigger angle, the current steering angle is used as the target steering angle.

8. The vehicle steering control method according to claim 1, characterized in that: Also includes: When the current steering angle is greater than the preset trigger angle, the torque applied by the power system to the drive wheel is increased to K times the original torque, where K is the ratio of the target steering angle to the current steering angle.

9. A vehicle steering control system, characterized in that: include: A first sensor for detecting a current steering angle of the vehicle; a brake, which is arranged on the driving wheel; a second sensor, which is used to detect the rotation speed of the driving wheel; a controller electrically connected to the first sensor, the second sensor and the brake; The controller acquires a corresponding target steering angle based on the current steering angle; The controller acquires a target differential speed ratio of the driving wheels based on the target steering angle, wherein the target differential speed ratio is a differential speed ratio when the driving wheels are turned to the target steering angle; and the controller adjusts the differential speed ratio of the driving wheels to the target differential speed ratio; Wherein, when the current steering angle is greater than a preset trigger angle and less than a maximum steering angle of the wheel, the controller uses the sum of a target angle difference and the preset trigger angle as the target steering angle, the target angle difference is obtained based on a preset maximum expected angle, the maximum steering angle, the preset trigger angle and the current steering angle, the maximum expected steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle; When the current steering angle is equal to the maximum steering angle, the controller uses the maximum desired steering angle as the target steering angle.

10. The vehicle steering control system according to claim 9, characterized in that: The controller uses the brake to adjust the rotation speed of the outer wheel and / or inner wheel of the driving wheel so that the differential ratio of the driving wheel is equal to the target differential ratio; wherein the inner wheel is a wheel among the driving wheels that is relatively close to the steering center of the vehicle, and the outer wheel is a wheel among the driving wheels that is relatively far from the steering center of the vehicle.

11. The vehicle steering control system according to claim 9, characterized in that: The vehicle steering control system also includes a power system, which includes a drive motor and a drive shaft. The drive motor is arranged on the vehicle body, and the drive shaft is connected to the drive motor in a transmission manner. The drive wheels are located on both sides of the vehicle body, and the drive wheels are connected to the drive shaft. When the controller detects that the current steering angle is greater than the preset trigger angle, the controller drives the power system to increase the torque applied to the drive wheel to K times the original torque, where K is the ratio of the target steering angle to the current steering angle.

12. A vehicle, characterized in that: include: Car body; driving wheels, which are arranged on both sides of the vehicle body; A first sensor for detecting a current steering angle of the vehicle; a brake, which is arranged on the driving wheel; a second sensor, which is used to detect the rotation speed of the driving wheel; a controller electrically connected to the first sensor, the second sensor and the brake; The controller acquires a corresponding target steering angle based on the current steering angle; The controller acquires a target differential speed ratio of the driving wheels based on the target steering angle, wherein the target differential speed ratio is a differential speed ratio when the driving wheels are turned to the target steering angle; and the controller adjusts the differential speed ratio of the driving wheels to the target differential speed ratio; Wherein, when the current steering angle is greater than a preset trigger angle and less than a maximum steering angle of the wheel, the controller uses the sum of a target angle difference and the preset trigger angle as the target steering angle, the target angle difference is obtained based on a preset maximum expected angle, the maximum steering angle, the preset trigger angle and the current steering angle, the maximum expected steering angle is greater than the maximum steering angle, and the target steering angle is greater than the current steering angle; When the current steering angle is equal to the maximum steering angle, the controller uses the maximum desired steering angle as the target steering angle.

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