Vehicle lateral anti-tilt control method

Abstract

The invention discloses a vehicle lateral anti-tilt control method, comprising: S1: collecting driving parameters of the vehicle in a driving state; S2: determining the linear velocity of each tire according to the vehicle speed, the steering wheel input angle and the dynamic model; S3: determining the dynamic rolling radius of each tire according to the linear velocity and the angular velocity of each tire; S4: determining the rolling radius difference of each tire and the rolling radius difference of the left and right tires according to the dynamic rolling radius and the static rolling radius of each tire; S5: determining the left and right suspension pressure stroke difference according to the pre-stored functional relationship between the suspension pressure change value corresponding to each tire and the rolling radius difference and the tire pressure, the tire pressure of each tire, the corresponding suspension pressure change value, the suspension stiffness and the rolling radius difference; S6: adjusting the left and right suspension strokes according to the rolling radius difference of the left tire and the rolling radius difference of the right tire and the left and right suspension pressure stroke difference. The accuracy of left and right suspension adjustment can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of automobiles, and in particular relates to a vehicle lateral anti-tilt control method. Background Art

[0002] At present, vehicles mainly use sensors to obtain the left and right height data of the suspension before adjusting the vehicle's tilt. However, the data obtained by the sensor has a transmission lag, and if the obtained data fluctuates greatly, the data accuracy will be affected. Therefore, when the vehicle is driving on a road with a large lateral slope, getting out of trouble on an off-road road, or turning at high speed, the vehicle's suspension has poor accuracy in adjusting the vehicle's roll according to different road conditions, resulting in poor handling and comfort performance of the vehicle. At this time, the driver and passengers will lack confidence in the vehicle's driving safety status, and will also feel more tired after a long driving time. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that when a vehicle is currently driving on a road with a large lateral slope, escaping from an off-road road, or turning at high speed, the vehicle's suspension has poor accuracy in adjusting the vehicle's roll according to different road conditions, resulting in poor handling stability and comfort performance of the vehicle. The present invention provides a vehicle lateral anti-tilt control method that can improve the accuracy of left and right suspension adjustment.

[0004] In order to solve the above technical problems, the embodiment of the present invention discloses a vehicle lateral anti-tilt control method, comprising the following steps:

[0005] S1: collecting driving parameters of the vehicle in a driving state, wherein the driving parameters include vehicle speed, input angle of the steering wheel, angular velocity of each tire of the vehicle, tire pressure of each tire, suspension downforce change value corresponding to each tire, and suspension stiffness;

[0006] S2: determining the linear speed of each tire of the vehicle according to the vehicle speed and the input angle of the steering wheel and a preset dynamic model; wherein the dynamic model includes the vehicle wheelbase, track width, distance from the center of rotation to the front axle, distance from the center of rotation to the rear axle, and front wheel steering characteristics;

[0007] S3: determining a dynamic rolling radius of each tire according to the linear velocity and angular velocity of each tire;

[0008] S4: determining the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire according to the dynamic rolling radius of each tire and the pre-stored static rolling radius;

[0009] S5: determining the left and right suspension downforce travel difference according to the pre-stored functional relationship between the suspension downforce change value corresponding to each tire, the rolling radius difference and the tire pressure, the collected tire pressure of each tire, the suspension downforce change value corresponding to each tire, the suspension stiffness, and the determined rolling radius difference of each tire;

[0010] S6: adjusting the left and right suspension strokes according to the rolling radius difference between the left tire and the right tire and the left and right suspension downward stroke difference.

[0011] According to the above technical solution, the driving parameters of the vehicle in the driving state are first collected, and then the dynamic model of the vehicle is established, and the driving parameters are input to determine the linear velocity of each tire. Further, the dynamic rolling radius of each tire, the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire are determined according to the linear velocity and angular velocity of each tire. Then, according to the functional relationship between the suspension downforce change value corresponding to each tire and the rolling radius difference and tire pressure, the tire pressure of each tire, the corresponding suspension downforce change value, the rolling radius difference, and the suspension stiffness, the left and right suspension downforce stroke difference is determined. Finally, according to the size relationship between the rolling radius difference of the left tire and the rolling radius difference of the right tire, and the left and right suspension downforce stroke difference, the left and right suspension strokes are adjusted. The left and right suspension downforce stroke difference determined in this way has a high accuracy, which can improve the accuracy of the left and right suspension adjustment, that is, more accurately adjust the left and right suspension heights of the vehicle, thereby accurately compensating for the body roll caused by the road surface or lateral acceleration, and improving the vehicle's handling stability and comfort performance.

[0012] According to another specific embodiment of the present invention, in the vehicle lateral anti-tilt control method disclosed in the embodiment of the present invention, step S6 includes:

[0013] If the rolling radius difference of the left tire is greater than that of the right tire, the right suspension travel is adjusted upward by the difference in downward travel of the left and right suspensions;

[0014] If the rolling radius difference of the left tire is smaller than that of the right tire, the left suspension travel is adjusted upward by the difference in downward travel of the left and right suspensions;

[0015] If the rolling radius difference of the left tires is equal to the rolling radius difference of the right tires, the suspension travel is not adjusted.

[0016] By adopting the above technical solution, the ground clearance of the left and right suspensions can be adjusted more accurately according to the rolling radius difference between the left tire and the right tire, thereby improving the comfort performance of the vehicle.

[0017] According to another specific embodiment of the present invention, the vehicle lateral anti-tilt control method disclosed in the embodiment of the present invention, in step S2, determining the linear speed of each tire includes the following steps:

[0018] S21: determining the steering angle of the left tire and the steering angle of the right tire according to the front wheel steering characteristics in the dynamic model and the collected input angle of the steering wheel; wherein the front wheel steering characteristics include the left front wheel steering characteristics and the right front wheel steering characteristics;

[0019] S22: determining the movement radius of each tire and the movement radius of the rotation center of the vehicle according to the turning angle of the left tire, the turning angle of the right tire, the wheelbase of the vehicle in the dynamic model, the distance between the rotation center and the rear axle, and the wheelbase;

[0020] S23: determining the angular velocity of the rotation center according to the movement radius of the rotation center and the collected vehicle speed;

[0021] S24: Determine the linear velocity of each tire according to the angular velocity of the rotation center and the movement radius of each tire.

[0022] By adopting the above technical solution, the specific value of the linear speed of each tire can be accurately obtained, providing more accurate data support for the subsequent determination of the left and right suspension downward stroke difference.

[0023] According to another specific embodiment of the present invention, in the vehicle lateral anti-tilt control method disclosed in the embodiment of the present invention, in step S21, the turning angle of the left tire and the turning angle of the right tire are respectively determined according to the following formulas:

[0024] θ left =θ·K left

[0025] θ right =θ·K right

[0026] Among them, θ left is the turning angle of the left tire, θ right is the turning angle of the right tire, θ is the input angle of the steering wheel, K left is the left front wheel steering characteristic, K right It is the right front wheel steering characteristic.

[0027] By adopting the above technical solution, the specific values ​​of the turning angles of the left tire and the right tire can be obtained through the above formula, providing more accurate data support for subsequently determining the movement radius of each tire.

[0028] According to another specific embodiment of the present invention, in the vehicle lateral anti-tilt control method disclosed in the embodiment of the present invention, in step S22, the movement radius of each tire and the movement radius of the rotation center are respectively determined according to the following formulas:

[0029] R FL =L / sinθ left

[0030] R FR =L / sinθ right

[0031] R RL =L / tanθ left

[0032] R RR =L / tanθ right

[0033] R CM =b / sinθ cm

[0034] tanθ cm =b / (R RL +t / 2)

[0035] Among them, R FL is the moving radius of the left front tire, R FR is the movement radius of the right front tire, R RL is the movement radius of the left rear tire, R RR is the movement radius of the right rear tire, L is the vehicle wheelbase, R CM is the radius of the rotation center, b is the distance from the rotation center to the rear axle, θ cm is the rotation angle of the rotation center, and t is the wheelbase.

[0036] By adopting the above technical solution, the precise values ​​of the moving radius of each tire and the moving radius of the rotation center can be obtained through the above formula, providing more accurate data support for the subsequent determination of the moving angular velocity of the rotation center and the moving angular velocity of the rotation center.

[0037] According to another specific embodiment of the present invention, in the vehicle lateral anti-tilt control method disclosed in the embodiment of the present invention, in step S23, the angular velocity of the rotation center is determined according to the following formula:

[0038]

[0039] in, is the angular velocity of the rotation center, and v is the vehicle speed.

[0040] By adopting the above technical solution, the precise value of the angular velocity of the rotation center can be obtained through the above formula, providing more accurate data support for the subsequent determination of the linear velocity of each tire.

[0041] According to another specific embodiment of the present invention, in the vehicle lateral anti-tilt control method disclosed in the embodiment of the present invention, in step S24, the linear speed of each tire is determined according to the following formula:

[0042]

[0043]

[0044]

[0045]

[0046] Among them, l FL is the linear speed of the left front tire, l FR is the linear speed of the right front tire, l RL is the linear speed of the left rear tire, l RR is the linear speed of the right rear tire.

[0047] By adopting the above technical solution, the accurate value of the linear speed of each tire can be obtained through the above formula, providing more accurate data support for subsequently determining the dynamic rolling radius of each tire.

[0048] According to another specific embodiment of the present invention, in the vehicle lateral anti-tilt control method disclosed in the embodiment of the present invention, in step S3, the dynamic rolling radius of each tire is determined according to the following formula:

[0049]

[0050]

[0051]

[0052]

[0053] in, is the dynamic rolling radius of the left front tire, is the dynamic rolling radius of the right front tire, is the dynamic rolling radius of the left rear tire, is the dynamic rolling radius of the right rear tire, ω FL is the angular velocity of the left front tire, ω FR is the angular velocity of the right front tire, ω RL is the angular velocity of the left rear tire, ω RR is the angular velocity of the right rear tire.

[0054] By adopting the above technical solution, the precise value of the dynamic rolling radius of each tire can be obtained through the above formula, providing more accurate data support for subsequently determining the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire.

[0055] According to another specific embodiment of the present invention, in the vehicle lateral anti-tilt control method disclosed in the embodiment of the present invention, in step S4, the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire are determined according to the following formula;

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062] in, is the rolling radius difference of the left front tire, is the rolling radius difference of the right front tire, is the rolling radius difference of the left rear tire, is the rolling radius difference of the right rear tire, is the static rolling radius of the left front tire, is the static rolling radius of the right front tire, is the static rolling radius of the left rear tire, is the static rolling radius of the right rear tire, is the rolling radius difference of the left tire, The rolling radius of the right tire is different.

[0063] By adopting the above technical solution, the above formula can be used to obtain the precise values ​​of the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire, thereby providing more accurate data support for subsequently determining the left and right suspension downward stroke difference.

[0064] According to another specific embodiment of the present invention, in the vehicle lateral anti-tilt control method disclosed in the embodiment of the present invention, in step S5, the left and right suspension downward stroke difference is determined according to the following formula:

[0065]

[0066] ΔS FL =ΔF FL / k, ΔS FR =ΔF FR / k, ΔS RL =ΔF RL / k, ΔS RR =ΔF RR / k

[0067] ΔS L =(ΔS FL +ΔS RL ) / 2

[0068] ΔS R =(ΔS FR +ΔS RR ) / 2

[0069] ΔS=|ΔS L -ΔS R |

[0070] Where, ΔF FL , ΔF FR , ΔF RL , ΔF RR are the suspension downforce changes corresponding to the left front tire, right front tire, left rear tire, and right rear tire, respectively. FL , P FR , P RL , P RR are the tire pressures of the left front tire, right front tire, left rear tire, and right rear tire, respectively, ΔS FL , ΔS FR , ΔS RL , ΔS RR are the suspension travel differences corresponding to the left front tire, right front tire, left rear tire, and right rear tire, respectively; k is the suspension stiffness, ΔS L is the suspension travel difference corresponding to the left tire, ΔS R is the suspension travel difference corresponding to the right tire, and ΔS is the difference in downward pressure travel between the left and right suspensions.

[0071] By adopting the above technical solution, the precise value of the difference in downward travel of the left and right suspensions can be obtained through the above formula, providing data support for accurately adjusting the ground clearance of the left and right suspensions.

[0072] The beneficial effects of the present invention are:

[0073] The present invention provides a vehicle lateral anti-tilt control method, firstly, the driving parameters of the vehicle in the driving state are collected, then the dynamic model of the vehicle is established, and the driving parameters are input to determine the linear velocity of each tire. Further, the dynamic rolling radius of each tire, the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire are determined according to the linear velocity and angular velocity of each tire. Then, according to the functional relationship between the suspension downforce change value corresponding to each tire and the rolling radius difference and tire pressure, the tire pressure of each tire, the corresponding suspension downforce change value, the rolling radius difference, and the suspension stiffness, the left and right suspension downforce stroke difference is determined. Finally, according to the size relationship between the rolling radius difference of the left tire and the rolling radius difference of the right tire, and the left and right suspension downforce stroke difference, the left and right suspension strokes are adjusted. In this way, the accuracy of the left and right suspension adjustment can be improved, that is, the left and right ground clearances of the vehicle can be adjusted more accurately, thereby accurately compensating for the body roll caused by the road surface or lateral acceleration, and improving the vehicle's handling stability and comfort performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 A flow chart of a vehicle lateral anti-tilt control method according to an embodiment of the present invention;

[0075] Figure 2 A graph showing the relationship between the input angle of the steering wheel and the turning angles of the left tire and the right tire of a certain vehicle model;

[0076] Figure 3 A schematic diagram of the data size of a dynamic model of a vehicle lateral anti-tilt control method according to an embodiment of the present invention;

[0077] Figure 4 It is a relationship diagram between the measured data and the fitted data of the suspension downforce and the change value of the tire rolling radius when the tire pressure is 200kap;

[0078] Figure 5 This is a relationship diagram between the measured data and the fitted data of the suspension downforce and the change in tire rolling radius when the tire pressure is 210kap. DETAILED DESCRIPTION

[0079] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may extend based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0080] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0081] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0082] The terms “first”, “second”, etc. are only used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0083] In the description of this embodiment, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this embodiment can be understood according to specific circumstances.

[0084] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0085] like Figure 1 As shown, an embodiment of the present invention discloses a vehicle lateral anti-tilt control method, comprising the following steps:

[0086] S1: Collect driving parameters of the vehicle in driving state, wherein the driving parameters include vehicle speed (mm / s), steering wheel input angle (°), angular velocity of each tire of the vehicle (° / s), tire pressure of each tire (kpa), suspension downforce change value corresponding to each tire (N), and suspension stiffness (N / mm).

[0087] In this implementation manner, it should be noted that the angular velocity of each tire can be obtained by wheel speed sensors respectively arranged on the four wheels in the chassis electronic stability control system.

[0088] S2: Determine the linear speed (mm / s) of each tire of the vehicle according to the vehicle speed, the input angle of the steering wheel and a preset dynamic model; wherein the dynamic model includes the vehicle wheelbase (mm), the track (mm), the distance from the center of rotation to the front axle (mm), the distance from the center of rotation to the rear axle (mm) and the front wheel steering characteristics.

[0089] In this embodiment, it should be noted that the center of rotation is the center of mass of the vehicle's physical characteristics, and its position is fixed and can be calculated through design in the vehicle design stage, or measured through actual vehicle in the later vehicle development process. After determining the position of the center of rotation, the distance from the center of rotation to the front axle and the distance from the center of rotation to the rear axle can be determined in the vehicle design stage or in the later vehicle development process. The front wheel steering characteristics include the left front wheel steering characteristics and the right front wheel steering characteristics, which can be understood as a series of variable transmission ratios. The input angle of the steering wheel is transmitted to the wheels through a steering trapezoidal transmission mechanism composed of a power assist device, a steering gear and a steering tie rod. This variable speed ratio can also be calculated through design in the vehicle design stage, and can also be measured through actual vehicle in the later vehicle development process. Figure 2 The relationship diagram between the input angle of the steering wheel and the turning angle of the left and right tires of a certain vehicle model is shown in Figure 1. The ratio of the turning angle of the left tire to the input angle of the steering wheel is the left front wheel steering characteristic, and the ratio of the turning angle of the right tire to the input angle of the steering wheel is the right front wheel steering characteristic. Figure 2 As shown in the figure, when the input angle of the steering wheel is positive, it means that the vehicle is turning left, and when the input angle of the steering wheel is negative, it means that the vehicle is turning right. For example, when the input angle of the steering wheel is 200° when a certain vehicle model turns left, the turning angle of the right front (right) tire is about 12.5°, and the turning angle of the left front (left) wheel is about 13°. Therefore, it can be determined that the steering characteristic of the left front wheel is about 0.065, and the steering characteristic of the right front wheel is about 0.0625.

[0090] Figure 3 FIG. 1 is a schematic diagram of the data size of the dynamic model of the vehicle lateral anti-tilt control method according to an embodiment of the present invention. Figure 3 As shown, C mis the rotation center, a is the distance from the rotation center to the front axle, b is the distance from the rotation center to the rear axle, L is the vehicle wheelbase, t is the wheelbase, v is the vehicle speed, θ left is the turning angle of the left tire, θ right is the turning angle of the right tire, θ cm is the angle of rotation center, R FL is the moving radius of the left front tire, R FR is the movement radius of the right front tire, R CM is the radius of motion of the rotation center.

[0091] S3: Determine the dynamic rolling radius (mm) of each tire based on the linear velocity and angular velocity of each tire.

[0092] S4: Determine the rolling radius difference (mm) of each tire, the rolling radius difference (mm) of the left tire, and the rolling radius difference (mm) of the right tire according to the dynamic rolling radius of each tire and the pre-stored static rolling radius (mm).

[0093] It should be noted that in this embodiment, due to physical characteristics, the center of gravity of the vehicle will shift to the outside during the turning process, causing axle load transfer, resulting in different suspension downforces on the inside and outside (left and right), which is a vehicle dynamic characteristic. Due to the different suspension downforces on the inside and outside (left and right) of the vehicle, the static rolling radius of each tire and the dynamic rolling radius of each tire determined according to the dynamic model are different.

[0094] S5: According to the pre-stored functional relationship between the suspension downforce change value corresponding to each tire, the rolling radius difference and the tire pressure, the collected tire pressure of each tire, the suspension downforce change value corresponding to each tire, the suspension stiffness, and the determined rolling radius difference of each tire, the left and right suspension downforce travel difference (mm) is determined.

[0095] It should be noted that the pre-stored functional relationship between the suspension downforce change value corresponding to each tire, the rolling radius difference and the tire pressure can be determined through early development calibration.

[0096] S6: adjusting the left and right suspension strokes according to the rolling radius difference between the left tire and the right tire and the left and right suspension downward stroke difference.

[0097] In a specific implementation, step S6 includes:

[0098] If the rolling radius difference of the left tire is greater than that of the right tire, the right suspension travel is adjusted upward by the difference in downward travel of the left and right suspensions;

[0099] If the rolling radius difference of the left tire is smaller than that of the right tire, the left suspension travel is adjusted upward by the difference in downward travel of the left and right suspensions;

[0100] If the rolling radius difference of the left tires is equal to the rolling radius difference of the right tires, the suspension travel is not adjusted.

[0101] According to the above technical solution, the driving parameters of the vehicle in the driving state are first collected, and then the dynamic model of the vehicle is established, and the driving parameters are input to determine the linear velocity of each tire. Further, the dynamic rolling radius of each tire, the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire are determined according to the linear velocity and angular velocity of each tire. Then, according to the functional relationship between the suspension downforce change value corresponding to each tire and the rolling radius difference and tire pressure, the tire pressure of each tire, the corresponding suspension downforce change value, the rolling radius difference, and the suspension stiffness, the left and right suspension downforce stroke difference is determined. Finally, according to the size relationship between the rolling radius difference of the left tire and the rolling radius difference of the right tire, and the left and right suspension downforce stroke difference, the left and right suspension strokes are adjusted. In this way, the accuracy of the left and right suspension adjustment can be improved, that is, the left and right suspension heights of the vehicle can be adjusted more accurately, thereby accurately compensating for the body roll caused by the road surface or lateral acceleration, and improving the vehicle's handling stability and comfort performance.

[0102] In a specific implementation, in step S2, determining the linear speed of each tire includes the following steps:

[0103] S21: determining the steering angle of the left tire and the steering angle of the right tire according to the front wheel steering characteristics in the dynamic model and the collected input angle of the steering wheel; wherein the front wheel steering characteristics include the left front wheel steering characteristics and the right front wheel steering characteristics;

[0104] S22: determining the movement radius of each tire and the movement radius of the rotation center of the vehicle according to the turning angle of the left tire, the turning angle of the right tire, the wheelbase of the vehicle in the dynamic model, the distance between the rotation center and the rear axle, and the wheelbase;

[0105] S23: determining the angular velocity of the rotation center according to the movement radius of the rotation center and the collected vehicle speed;

[0106] S24: Determine the linear velocity of each tire according to the angular velocity of the rotation center and the movement radius of each tire.

[0107] By adopting the above technical solution, the specific value of the linear speed of each tire can be accurately obtained, providing more accurate data support for the subsequent determination of the left and right suspension downward stroke difference.

[0108] In a specific implementation, in step S21, the turning angle of the left tire and the turning angle of the right tire are determined according to the following formulas:

[0109] θ left =θ·K left

[0110] θ right =θ·K right

[0111] Among them, θ left is the turning angle of the left tire, θ right is the turning angle of the right tire, θ is the input angle of the steering wheel, K left is the left front wheel steering characteristic, K right It is the right front wheel steering characteristic.

[0112] By adopting the above technical solution, the specific values ​​of the turning angles of the left tire and the right tire can be obtained through the above formula, providing more accurate data support for subsequently determining the movement radius of each tire.

[0113] In a specific implementation, in step S22, the movement radius of each tire and the movement radius of the rotation center are determined respectively according to the following formulas:

[0114] R FL =L / sinθ left

[0115] R FR =L / sinθ right

[0116] R RL =L / tanθ left

[0117] R RR =L / tanθ right

[0118] R CM =b / sinθ cm

[0119] tanθ cm =b / (R RL +t / 2)

[0120] Among them, R FL is the moving radius of the left front tire, R FR is the movement radius of the right front tire, R RL is the movement radius of the left rear tire, R RR is the movement radius of the right rear tire, L is the vehicle wheelbase, R CM is the radius of the rotation center, b is the distance from the rotation center to the rear axle, θ cm is the rotation angle of the rotation center, and t is the wheelbase.

[0121] By adopting the above technical solution, the precise values ​​of the moving radius of each tire and the moving radius of the rotation center can be obtained through the above formula, providing more accurate data support for the subsequent determination of the moving angular velocity of the rotation center and the moving angular velocity of the rotation center.

[0122] In a specific implementation, in step S23, the angular velocity of the rotation center is determined according to the following formula:

[0123]

[0124] in, is the angular velocity of the rotation center, and v is the vehicle speed.

[0125] By adopting the above technical solution, the precise value of the angular velocity of the rotation center can be obtained through the above formula, providing more accurate data support for the subsequent determination of the linear velocity of each tire.

[0126] In a specific implementation, in step S24, the linear speed of each tire is determined according to the following formula:

[0127]

[0128]

[0129]

[0130]

[0131] Among them, l FL is the linear speed of the left front tire, l FR is the linear speed of the right front tire, l RL is the linear speed of the left rear tire, l RR is the linear speed of the right rear tire.

[0132] It should be noted that, in this embodiment, the angular velocity of each tire in the same vehicle is the same as the angular velocity of the rotation center, so the linear velocity of each tire can be determined based on the angular velocity of the rotation center and the movement radius of each tire.

[0133] By adopting the above technical solution, the accurate value of the linear speed of each tire can be obtained through the above formula, providing more accurate data support for subsequently determining the dynamic rolling radius of each tire.

[0134] In a specific implementation, in step S3, the dynamic rolling radius of each tire is determined according to the following formula:

[0135]

[0136]

[0137]

[0138]

[0139] in, is the dynamic rolling radius of the left front tire, is the dynamic rolling radius of the right front tire, is the dynamic rolling radius of the left rear tire, is the dynamic rolling radius of the right rear tire, ω FL is the angular velocity of the left front tire, ω FR is the angular velocity of the right front tire, ω RL is the angular velocity of the left rear tire, ω RR is the angular velocity of the right rear tire.

[0140] By adopting the above technical solution, the precise value of the dynamic rolling radius of each tire can be obtained through the above formula, providing more accurate data support for subsequently determining the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire.

[0141] In a specific implementation, in step S4, the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire are determined according to the following formula:

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148] in, is the rolling radius difference of the left front tire, is the rolling radius difference of the right front tire, is the rolling radius difference of the left rear tire, is the rolling radius difference of the right rear tire, is the static rolling radius of the left front tire, is the static rolling radius of the right front tire, is the static rolling radius of the left rear tire, is the static rolling radius of the right rear tire, is the rolling radius difference of the left tire, The rolling radius of the right tire is different.

[0149] By adopting the above technical solution, the above formula can be used to obtain the precise values ​​of the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire, thereby providing more accurate data support for subsequently determining the left and right suspension downward stroke difference.

[0150] In a specific implementation, in step S5, the left and right suspension downward stroke difference is determined according to the following formula:

[0151]

[0152] ΔS FL =ΔF FL / k, ΔS FR =ΔF FR / k, ΔS RL =ΔF RL / k, ΔS RR =ΔF RR / k

[0153] ΔS L =(ΔS FL +ΔS RL ) / 2

[0154] ΔS R =(ΔS FR +ΔS RR ) / 2

[0155] ΔS=|ΔS L -ΔS R |

[0156] Where, ΔF FL , ΔF FR , ΔF RL , ΔF RR are the suspension downforce changes corresponding to the left front tire, right front tire, left rear tire, and right rear tire, respectively. FL , P FR , P RL , P RR are the tire pressures of the left front tire, right front tire, left rear tire, and right rear tire, respectively, ΔS FL , ΔS FR , ΔS RL , ΔS RR are the suspension travel differences corresponding to the left front tire, right front tire, left rear tire, and right rear tire, respectively; k is the suspension stiffness, ΔS L is the suspension travel difference corresponding to the left tire, ΔS Ris the suspension travel difference corresponding to the right tire, and ΔS is the difference in downward pressure travel between the left and right suspensions.

[0157] It should be noted that in this embodiment, the rolling radius of the tire under different tire pressures is different when subjected to downforce, and the following can be obtained through early development and calibration: Figure 4 and Figure 5 Suspension downforce shown as a function of tire rolling radius change and tire pressure. Figure 4 This is the relationship between the measured data and the fitted data of the suspension downforce and the change in tire rolling radius when the tire pressure is 200kap. Figure 5 This is the relationship between the measured data and the fitted data of the suspension downforce and the tire rolling radius change when the tire pressure is 210 kap. Figure 4 and Figure 5 The solid line in the figure represents the relationship between the measured data of the suspension downforce and the tire rolling radius change value, and the dotted line represents the relationship between the fitted data of the suspension downforce and the tire rolling radius change value. Figure 4 and Figure 5 As shown, the fitted suspension downforce and the tire rolling radius change value are linearly related. According to the relationship between the suspension downforce, the tire rolling radius change value and the tire pressure, the pre-stored functional relationship between the suspension downforce change value, the rolling radius difference and the tire pressure corresponding to each tire can be further determined, that is, the functional relationship between the suspension downforce change value, the rolling radius difference and the tire pressure corresponding to each tire can be expressed as:

[0158] In this embodiment, the suspension downforce and suspension stiffness can be used to calculate the suspension downforce travel. Therefore, the functional relationship between the suspension downforce change value corresponding to each tire and the corresponding suspension travel difference and stiffness can be expressed as: ΔS FL =ΔF FL / k, ΔS FR =ΔF FR / k, ΔS RL =ΔF RL / k, ΔS RR =ΔF RR / k.

[0159] By adopting the above technical solution, the precise value of the difference in downward travel of the left and right suspensions can be obtained through the above formula, providing data support for accurately adjusting the ground clearance of the left and right suspensions.

[0160] The beneficial effects of the present invention are:

[0161] The present invention provides a vehicle lateral anti-tilt control method, firstly, the driving parameters of the vehicle in the driving state are collected, then the dynamic model of the vehicle is established, and the driving parameters are input to determine the linear velocity of each tire. Further, the dynamic rolling radius of each tire, the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire are determined according to the linear velocity and angular velocity of each tire. Then, according to the functional relationship between the suspension downforce change value corresponding to each tire and the rolling radius difference and tire pressure, the tire pressure of each tire, the corresponding suspension downforce change value, the rolling radius difference, and the suspension stiffness, the left and right suspension downforce stroke difference is determined. Finally, according to the size relationship between the rolling radius difference of the left tire and the rolling radius difference of the right tire, and the left and right suspension downforce stroke difference, the left and right suspension strokes are adjusted. In this way, the accuracy of the left and right suspension adjustment can be improved, that is, the left and right ground clearances of the vehicle can be adjusted more accurately, thereby accurately compensating for the body roll caused by the road surface or lateral acceleration, and improving the vehicle's handling stability and comfort performance.

[0162] Although the present invention has been illustrated and described with reference to certain preferred embodiments of the present invention, it should be understood by those skilled in the art that the above is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. Those skilled in the art may make various changes in form and details, including making several simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A vehicle lateral anti-tilt control method, characterized in that: The following steps are involved: S1: collecting driving parameters of the vehicle in a driving state, wherein the driving parameters include vehicle speed, input angle of the steering wheel, angular velocity of each tire of the vehicle, tire pressure of each tire, suspension downforce change value corresponding to each tire, and suspension stiffness; S2: determining the linear speed of each tire of the vehicle according to the vehicle speed, the input angle of the steering wheel and a preset dynamic model; wherein the dynamic model includes the vehicle wheelbase, the track width, the distance from the rotation center to the front axle, the distance from the rotation center to the rear axle and the front wheel steering characteristics; S3: determining a dynamic rolling radius of each tire according to the linear velocity and the angular velocity of each tire; S4: determining the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire according to the dynamic rolling radius of each tire and the pre-stored static rolling radius; S5: determining the left and right suspension downforce travel difference according to the pre-stored functional relationship between the suspension downforce change value corresponding to each tire, the rolling radius difference and the tire pressure, the collected tire pressure of each tire, the suspension downforce change value corresponding to each tire, the suspension stiffness, and the determined rolling radius difference of each tire; S6: adjusting the left and right suspension strokes according to the rolling radius difference between the left tire and the right tire, and the left and right suspension downward stroke difference.

2. The vehicle lateral anti-tilt control method according to claim 1, characterized in that: The step S6 comprises: If the rolling radius difference of the left tire is greater than the rolling radius difference of the right tire, the right suspension stroke is increased by the left and right suspension downward stroke difference; If the rolling radius difference of the left tire is smaller than the rolling radius difference of the right tire, the left suspension stroke is increased by the left and right suspension downward stroke difference; If the rolling radius difference of the left tire is equal to the rolling radius difference of the right tire, the suspension travel is not adjusted.

3. The vehicle lateral anti-tilt control method according to claim 1, characterized in that: In step S2, determining the linear speed of each tire comprises the following steps: S21: determining the steering angle of the left tire and the steering angle of the right tire according to the front wheel steering characteristics in the dynamic model and the collected input angle of the steering wheel; wherein the front wheel steering characteristics include the left front wheel steering characteristics and the right front wheel steering characteristics; S22: determining the movement radius of each tire and the movement radius of the rotation center of the vehicle according to the rotation angle of the left tire, the rotation angle of the right tire, the vehicle wheelbase in the dynamic model, the distance between the rotation center and the rear axle, and the wheelbase; S23: determining the angular velocity of the rotation center according to the movement radius of the rotation center and the collected vehicle speed; S24: Determine the linear velocity of each tire according to the angular velocity of the rotation center and the movement radius of each tire.

4. The vehicle lateral anti-tilt control method according to claim 3, characterized in that: In step S21, the turning angle of the left tire and the turning angle of the right tire are determined according to the following formulas: i left =θ·K left i right =θ·K right Among them, θ left is the turning angle of the left tire, θ right is the turning angle of the right tire, θ is the input angle of the steering wheel, K left is the left front wheel steering characteristic, K right is the right front wheel steering characteristic.

5. The vehicle lateral anti-tilt control method according to claim 4, characterized in that: In step S22, the movement radius of each tire and the movement radius of the rotation center are determined respectively according to the following formulas: R FL =L / sinθ left R FR =L / sinθ right R RL =L / tanθ left R RR =L / tanθ right R CM =b / sinθ cm tanθ cm =b / (R RL +t / 2) Among them, R FL is the moving radius of the left front tire, R FR is the movement radius of the right front tire, R RL is the movement radius of the left rear tire, R RR is the movement radius of the right rear tire, L is the vehicle wheelbase, R CM is the radius of motion of the rotation center, b is the distance from the rotation center to the rear axle, θ cm is the rotation angle of the rotation center, and t is the wheelbase.

6. The vehicle lateral anti-tilt control method according to claim 5, characterized in that: In step S23, the angular velocity of the rotation center is determined according to the following formula: in, is the angular velocity of the rotation center, and v is the vehicle speed.

7. The vehicle lateral anti-tilt control method according to claim 6, characterized in that: In step S24, the linear speed of each tire is determined according to the following formula: Among them, l FL is the linear speed of the left front tire, l FR is the linear speed of the right front tire, l RL is the linear speed of the left rear tire, l RR is the linear speed of the right rear tire.

8. The vehicle lateral anti-tilt control method according to claim 7, characterized in that: In step S3, the dynamic rolling radius of each tire is determined according to the following formula: in, is the dynamic rolling radius of the left front tire, is the dynamic rolling radius of the right front tire, is the dynamic rolling radius of the left rear tire, is the dynamic rolling radius of the right rear tire, ω FL is the angular velocity of the left front tire, ω FR is the angular velocity of the right front tire, ω RL is the angular velocity of the left rear tire, ω RR is the angular velocity of the right rear tire.

9. The vehicle lateral anti-tilt control method according to claim 8, characterized in that: In step S4, the rolling radius difference of each tire, the rolling radius difference of the left tire, and the rolling radius difference of the right tire are determined according to the following formula; in, is the rolling radius difference of the left front tire, is the rolling radius difference of the right front tire, is the rolling radius difference of the left rear tire, is the rolling radius difference of the right rear tire, is the static rolling radius of the left front tire, is the static rolling radius of the right front tire, is the static rolling radius of the left rear tire, is the static rolling radius of the right rear tire, is the rolling radius difference of the left tire, The rolling radius of the right tire is different.

10. The vehicle lateral anti-tilt control method according to claim 9, characterized in that: In step S5, the left and right suspension downward stroke difference is determined according to the following formula: ΔS FL =ΔF FL / k,ΔS FR =ΔF FR / k,ΔS RL =ΔF RL / k,ΔS RR =ΔF RR / k ΔS L =(ΔS FL +ΔS RL ) / 2 ΔS R =(ΔS FR +ΔS RR ) / 2 ΔS=|ΔS L -ΔS R | Where, ΔF FL , ΔF FR , ΔF RL , ΔF RR are the suspension downforce changes corresponding to the left front tire, right front tire, left rear tire, and right rear tire, respectively. FL , P FR , P RL , P RR are the tire pressures of the left front tire, right front tire, left rear tire, and right rear tire, respectively, ΔS FL , ΔS FR , ΔS RL , ΔS RR are the suspension travel differences corresponding to the left front tire, right front tire, left rear tire, and right rear tire, respectively; k is the suspension stiffness; ΔS L is the suspension travel difference corresponding to the left tire, ΔS R is the suspension travel difference corresponding to the right tire, and ΔS is the left and right suspension downward stroke difference.

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