A method, device, equipment and storage medium for coordinated control of four wheels of a vehicle

Abstract

The present application relates to a method, device, equipment and storage medium for four-wheel collaborative control of an automobile. The method establishes a first relationship in which the inner front wheel steering angle θ1 and the steering wheel angle α are linearly related and have the same positive and negative signs, and a second relationship in which the distance L2 between the instantaneous center and the rear axle and the absolute value of the steering wheel angle α are linearly related. The inner front wheel steering angle θ1, the outer front wheel steering angle θ2, the inner rear wheel steering angle θ3 and the outer rear wheel steering angle θ4 are respectively calculated by using the steering wheel angle α, the first relationship and the second relationship, so as to perform collaborative control of the steering angles of all the tires of the vehicle according to the calculation results. The method provided by the present application gets rid of the constraint of the mechanical connection mechanism on the wheel steering angle, enables the steering angles of each wheel to be output along the ideal characteristics, turns around the only vehicle instantaneous center, improves the stability of the vehicle, reduces the lateral wear degree of the tires to the lowest, and also makes the control of the rear wheel steering angle have non-linear characteristics, which is more in line with the driver's expectation of the steering system characteristics.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a method, device, equipment and storage medium for coordinated control of four wheels of a vehicle. Background Art

[0002] At present, in the development of passenger car models, generally only front-wheel steering is configured, while for some off-road models, rear-wheel steering is configured. When the vehicle speed is less than a certain value, the rear wheels are turned in the opposite direction relative to the front wheels to achieve the purpose of reducing the turning radius and improving passability.

[0003] In the related technology, for front-wheel steering, the movement of the left and right steering tie rods is currently controlled by the steering wheel-steering column-steering gear, combined with the EPS motor power assistance, so as to achieve the purpose of manipulating the steering angle of the left and right front wheels; for rear-wheel steering, the steering wheel angle information is currently obtained by a controller, the rear wheel steering demand is calculated, and the movement of the left and right steering tie rods is controlled by the execution motor, so as to achieve the purpose of manipulating the steering angle of the left and right rear wheels; in essence, the front and rear wheel steering are transmitted by a connecting rod mechanism, and the front wheel steering is not decoupled from the steering wheel, and is still a continuation of the mechanical steering system. The steering angles of the left and right front wheels are constrained by the connecting rod mechanism and are in a fixed corresponding relationship; although the rear-wheel steering is decoupled from the steering wheel, its actuator is still a connecting rod mechanism, which is constrained by it, and the steering angles of the left and right rear wheels are also in a fixed corresponding relationship.

[0004] Therefore, the above scheme has the following disadvantages: First, the front and rear steering mechanisms are still linkage mechanisms, and the steering angles of the left and right wheels are restricted by the mechanism, and can only approximately realize the corresponding relationship of large steering angle of the inner wheel and small steering angle of the outer wheel, which deviates from the ideal corresponding relationship under the full steering angle range; secondly, the front and rear steering mechanisms are designed independently of each other, and the steering angles of the four wheels are not matched enough. When the four wheels are turned at the same time, the position of the instantaneous center of the vehicle is not unique, the driving characteristics of the vehicle are poor, and lateral wear of the tires is easily caused; in addition, the rear wheel steering angle is linearly related to the front wheel steering angle, but for the driver, the ideal relationship should be nonlinear, that is, when the steering wheel is turned at a small angle, generally only the front wheel steering intervention is required, and the rear wheel steering does not need to intervene too much; when the steering wheel is turned at a large angle, the rear wheel steering needs to fully intervene to reduce the turning radius. Summary of the invention

[0005] The embodiments of the present application provide a method, device, equipment and storage medium for coordinated control of four wheels of a vehicle to solve the problems in the related art that the steering angles of the left and right wheels deviate from the ideal corresponding relationship under the full steering angle range, the position of the instantaneous center of the whole vehicle is not unique, and the linear relationship between the rear wheel steering angle and the front wheel steering angle is inconsistent with the theoretical relationship.

[0006] In a first aspect, a method for coordinated control of four wheels of a vehicle is provided, the steps of which include:

[0007] Establish the inner front wheel steering angle θ 1 and the first relationship of the steering wheel angle α, so that the inner front wheel steering angle θ 1 It is linearly related to the steering wheel angle α and has the same positive and negative sign;

[0008] Establish the distance L between the instant center and the rear axle 2 and the second relationship of the steering wheel angle α, so that the instantaneous center is at a distance L from the rear axle 2 It is linearly related to the absolute value of the steering wheel angle α;

[0009] Obtain the steering wheel angle α of the vehicle, and calculate the inner front wheel steering angle θ by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 ;

[0010] According to the inner front wheel steering angle θ 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 The steering angle of all tires of the vehicle is coordinated and controlled.

[0011] In some embodiments, the first relationship is:

[0012] θ 1 =λα

[0013] Where λ is the steering angle transmission ratio.

[0014] In some embodiments, the second relationship is:

[0015] L 2 =K|α|

[0016] Where K is the instantaneous center forward coefficient.

[0017] In some embodiments, the outer front wheel steering angle θ is calculated by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship. 2 The calculation formula is:

[0018]

[0019] Among them, B is the distance between the intersection of the left and right wheel kingpin axes and the ground, and L is the front and rear wheelbase.

[0020] In some embodiments, the inner rear wheel steering angle θ is calculated by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship. 3 The calculation formula is:

[0021]

[0022] Among them, L is the front and rear wheelbase.

[0023] In some embodiments, the outer rear wheel steering angle θ is calculated by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship. 4 The calculation formula is:

[0024]

[0025] Among them, B is the distance between the intersection of the left and right wheel kingpin axes and the ground, and L is the front and rear wheelbase.

[0026] In some embodiments, the vehicle steering wheel angle α is obtained, and the inner front wheel steering angle θ is calculated by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 ,include:

[0027] Obtain vehicle geometry parameters and steering system characteristic parameters;

[0028] Utilizing the vehicle geometric parameters and the steering system characteristic parameters in combination with the first relationship and the second relationship to develop software for the steering system controller, and forming a calibration MAP diagram;

[0029] Obtain the vehicle's steering wheel angle α, and use the steering wheel angle α combined with the calibration MAP to calculate the inner front wheel steering angle θ 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 .

[0030] In a second aspect, a device for coordinated control of four wheels of a vehicle is provided, which is used to implement the steps of the method for coordinated control of four wheels of a vehicle, and includes:

[0031] Configuration module, which is used to establish the inner front wheel steering angle θ 1 and the first relationship of the steering wheel angle α, so that the inner front wheel steering angle θ 1 It is linearly related to the steering wheel angle α and has the same positive and negative sign. It is also used to establish the distance L between the instantaneous center and the rear axle.2 and the second relationship of the steering wheel angle α, so that the instantaneous center is at a distance L from the rear axle 2 It is linearly related to the absolute value of the steering wheel angle α;

[0032] A calculation module, which is used to obtain the steering wheel angle α of the vehicle, and to calculate the inner front wheel steering angle θ by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship respectively. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 ;

[0033] A control module is configured to control the inner front wheel steering angle θ according to the inner front wheel steering angle θ. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 The steering angle of all tires of the vehicle is coordinated and controlled.

[0034] In a third aspect, a device is provided, comprising a processor, a memory, and a computer program stored in the memory and executable by the processor, wherein when the computer program is executed by the processor, any step of the above-mentioned method for coordinated control of four wheels of a vehicle is implemented.

[0035] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored, wherein when the computer program is executed by a processor, any step of the above-mentioned method for coordinated control of four wheels of a vehicle is implemented.

[0036] The beneficial effects of the technical solution provided by this application include:

[0037] The embodiment of the present application provides a method for coordinated control of four wheels of a vehicle. By establishing the inner front wheel steering angle θ 1 The first relationship is linearly related to the steering wheel angle α and has the same positive and negative relationship. The distance L between the instantaneous center and the rear axle is also established. 2 The second relationship is linearly related to the absolute value of the steering wheel angle α, and the inner front wheel steering angle θ is calculated by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4, so as to coordinately control the steering angles of all tires of the vehicle according to the calculation results. Therefore, this method gets rid of the constraints of the traditional mechanical connection mechanism on the steering angle of the wheel, and can make the steering angle of each wheel output along the ideal characteristics, turning around the only vehicle instantaneous center, improving the stability of the vehicle and reducing the lateral wear of the tires to a minimum; this method makes the control of the rear wheel steering angle have nonlinear characteristics, which is more in line with the driver's expectations of the steering system characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 A schematic diagram of the four-wheel coordinated control of a vehicle provided in an embodiment of the present application;

[0040] Figure 2 A relationship diagram between the instantaneous center longitudinal position and the steering wheel angle of the four-wheel coordinated control of the vehicle provided in the embodiment of the present application;

[0041] Figure 3 A diagram showing the relationship between the steering angles of each wheel and the steering wheel angle of the four-wheel coordinated control of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0043] The embodiment of the present application provides a method for coordinated control of four wheels of a vehicle, which can solve the problems in the related art that the steering angles of the left and right wheels deviate from the ideal corresponding relationship under the full steering angle range, the position of the instantaneous center of the whole vehicle is not unique, and the linear relationship between the rear wheel steering angle and the front wheel steering angle is inconsistent with the theoretical relationship.

[0044] See also Figure 1 As shown, the steps of this method are first to establish the inner front wheel steering angle θ 1 and the first relationship of the steering wheel angle α, so that the inner front wheel steering angle θ 1 It is linearly related to the steering wheel angle α and has the same positive and negative sign. Then, the distance L between the instantaneous center and the rear axle is established.2 and the second relationship of the steering wheel angle α, so that the instantaneous center is at a distance L from the rear axle 2 The absolute value of the steering wheel angle α is linearly related to the steering wheel angle α of the vehicle, and then the steering wheel angle α of the vehicle is obtained, and the inner front wheel steering angle θ is calculated by combining the first relationship and the second relationship using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 Finally, according to the inner front wheel steering angle θ 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 The steering angle of all the tires of the vehicle is coordinated and controlled. The inner front wheel refers to the tire on the left side of the front. Figure 1 FL is used to indicate that the outer front wheel refers to the tire located on the front right side. Figure 1 In FR, the inner rear wheel refers to the tire located on the left side of the rear. Figure 1 RL is used to indicate that the outer rear wheel refers to the tire located on the rear right side. Figure 1 It is expressed by RR.

[0045] Specifically, there is no mechanical connection between the steering wheel and the steering mechanism. The steering wheel is rotated to realize the steering of the wheels completely based on the electronic control system. The steering wheel angle signal is collected to calculate and control the steering angles of the four wheels to achieve ideal steering angle matching. This can solve the problem that the steering angles of the left and right wheels can only approximately achieve the corresponding relationship of the inner wheel with a large steering angle and the outer wheel with a small steering angle, which is different from the ideal corresponding relationship under the full angle range. It can also solve the problem that the steering angles of the four wheels are not matched enough due to the independent design of the front and rear steering mechanisms. When the four wheels are turned at the same time, the position of the instantaneous center of the whole vehicle is not unique, resulting in poor driving characteristics of the vehicle and easy lateral wear of the tires. In addition, whether it is front-wheel steering or rear-wheel steering, the left and right wheels are independently controlled by motors and are not connected by connecting rods, that is, the steering angles of the left and right wheels are completely decoupled. In addition to helping solve the problem of the non-unique position of the instantaneous center of the whole vehicle, it can also solve the problem of the linear relationship between the rear wheel steering angle and the front wheel steering angle, making the actual relationship a nonlinear relationship. Therefore, this method is based on the relationship between the steering angles of the four wheels and the steering wheel angle, combined with the vehicle geometric parameters and the steering system characteristic parameters, to achieve the purpose of coordinated control of the four-wheel steering angle, get rid of the constraints of the traditional mechanical connection mechanism on the wheel steering angle, and can make the steering angle of each wheel output along the ideal characteristic, turning around the only vehicle instantaneous center, thereby improving the stability of the vehicle and reducing the lateral wear of the tire to a minimum; this method makes the control of the rear wheel steering angle have nonlinear characteristics, which is more in line with the driver's expectations of the steering system characteristics.

[0046] Furthermore, the first relationship is:

[0047] θ 1 = λα Formula (1)

[0048] Where, λ in formula (1) is the steering angle transmission ratio, and formula (1) is the inner front wheel steering angle θ 1 Functional relationship f relative to steering wheel angle α 1 (α).

[0049] Furthermore, the second relationship is:

[0050] L 2 = K|α| Formula (2)

[0051] Where K is the instantaneous center forward coefficient.

[0052] Specifically, due to the wheelbase constraint, the distance between the instantaneous center and the front axle is L 1 The calculation formula is:

[0053] L 1 =LL 2 Formula (3)

[0054] Where L is the front and rear wheelbase. Combining formula (2) and formula (3) we can get formula (4):

[0055] L 1 =LK|α| Formula (4)

[0056] See also Figure 2 As shown in the figure, the relationship between the instantaneous center longitudinal position and the steering wheel angle α is given by Figure 1 The following geometric constraint relationship can be obtained:

[0057]

[0058]

[0059]

[0060]

[0061] Among them, B in the above formula is the distance between the intersection of the kingpin axes of the left and right wheels and the ground.

[0062] Furthermore, the outer front wheel steering angle θ is calculated by using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship, as well as formula (5) to formula (8): 2 The calculation formula is:

[0063]

[0064] Where B is the distance between the intersection of the left and right wheel kingpin axes and the ground, L is the front and rear wheelbase, and formula (9) is the inner front wheel steering angle θ 2 Functional relationship f relative to steering wheel angle α 2 (α).

[0065] Furthermore, the inner rear wheel steering angle θ is calculated by using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship, as well as formula (5) to formula (8): 3 The calculation formula is:

[0066]

[0067] Wherein, formula (10) is the inner front wheel steering angle θ 3 Functional relationship f relative to steering wheel angle α 3 (α).

[0068] Further, the outer rear wheel steering angle θ is calculated by using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship, as well as formula (5) to formula (8): 4The calculation formula is:

[0069]

[0070] Where B is the distance between the intersection of the left and right wheel kingpin axes and the ground. Formula (11) is the inner front wheel steering angle θ 4 Functional relationship f relative to steering wheel angle α 4 (α).

[0071] In addition, it is stipulated that when α is 0°, θ 1 ,θ 2 ,θ 3 ,θ 4 Both are 0°.

[0072] When the steering wheel is turned to the right, the inner and outer front wheels are turned to the right, and the inner and outer rear wheels are turned to the left, the above equations are still valid; see Figure 3 As shown in the figure, the functional relationship between the steering angle of each wheel and the steering wheel angle is shown. Figure 3 It can be seen that this method makes the control of the rear wheel steering angle have nonlinear characteristics, which is more in line with the driver's expectations of the steering system characteristics. Specifically, when the steering wheel angle |α| is less than 180°, that is, within half a circle of the steering wheel, the rear wheel steering angle is very small and does not affect the driver's direction judgment; when the steering wheel angle |α| is between 180° and 360°, that is, when the steering wheel is half a circle to one circle, the rear wheel steering angle increases faster; when the steering wheel angle |α| is greater than 360°, that is, when the steering wheel exceeds one circle until it approaches the limit position, the rear wheel steering angle increases rapidly, effectively shortening the turning radius and improving the passing performance.

[0073] Further, the steering wheel angle α of the vehicle is obtained, and the inner front wheel steering angle θ is calculated by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 The steps mainly include:

[0074] Obtain vehicle geometry parameters and steering system characteristic parameters;

[0075] Utilizing the vehicle geometric parameters and the steering system characteristic parameters in combination with the first relationship and the second relationship to develop software for the steering system controller, and forming a calibration MAP diagram;

[0076] Obtain the vehicle's steering wheel angle α, and use the steering wheel angle α combined with the calibration MAP to calculate the inner front wheel steering angle θ 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3and the outer rear wheel steering angle θ 4 .

[0077] Specifically, based on the relationship between the steering angles of the four wheels and the steering wheel angle, combined with vehicle geometric parameters such as vehicle geometric parameters and steering system characteristic parameters, the software development of the steering system controller is carried out to form a calibration MAP diagram, which is used as a basis to achieve the purpose of four-wheel steering angle coordinated control proposed in this method.

[0078] The present application also provides a device for coordinated control of four wheels of a vehicle, which is used to implement the steps of the method for coordinated control of four wheels of a vehicle, and includes:

[0079] Configuration module, which is used to establish the inner front wheel steering angle θ 1 and the first relationship of the steering wheel angle α, so that the inner front wheel steering angle θ 1 It is linearly related to the steering wheel angle α and has the same positive and negative sign. It is also used to establish the distance L between the instantaneous center and the rear axle. 2 and the second relationship of the steering wheel angle α, so that the instantaneous center is at a distance L from the rear axle 2 It is linearly related to the absolute value of the steering wheel angle α;

[0080] A calculation module, which is used to obtain the steering wheel angle α of the vehicle, and to calculate the inner front wheel steering angle θ by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship respectively. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 ;

[0081] A control module is configured to control the inner front wheel steering angle θ according to the inner front wheel steering angle θ. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 The steering angle of all tires of the vehicle is coordinated and controlled.

[0082] Furthermore, the first relationship is:

[0083] θ 1 = λα Formula (1)

[0084] Where, λ in formula (1) is the steering angle transmission ratio, and formula (1) is the inner front wheel steering angle θ 1 Functional relationship f relative to steering wheel angle α 1 (α).

[0085] Furthermore, the second relationship is:

[0086] L 2= K|α| Formula (2)

[0087] Where K is the instantaneous center forward coefficient.

[0088] Specifically, due to the wheelbase constraint, the distance between the instantaneous center and the front axle is L 1 The calculation formula is:

[0089] L 1 =LL 2 Formula (3)

[0090] Where L is the front and rear wheelbase. Combining formula (2) and formula (3) we can get formula (4):

[0091] L 1 =LK|α| Formula (4)

[0092] See also Figure 2 As shown in the figure, the relationship between the instantaneous center longitudinal position and the steering wheel angle α is given by Figure 3 The following geometric constraint relationship can be obtained:

[0093]

[0094]

[0095]

[0096]

[0097] Furthermore, the outer front wheel steering angle θ is calculated by using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship, as well as formula (5) to formula (8): 2 The calculation formula is:

[0098]

[0099] Among them, L is the front and rear wheelbase.

[0100] Furthermore, the inner rear wheel steering angle θ is calculated by using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship, as well as formula (5) to formula (8): 3 The calculation formula is:

[0101]

[0102] Further, the outer rear wheel steering angle θ is calculated by using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship, as well as formula (5) to formula (8): 4 The calculation formula is:

[0103]

[0104] Further, the steering wheel angle α of the vehicle is obtained, and the inner front wheel steering angle θ is calculated by combining the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α with the first relationship and the second relationship. 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 The steps mainly include:

[0105] Obtain vehicle geometry parameters and steering system characteristic parameters;

[0106] Utilizing the vehicle geometric parameters and the steering system characteristic parameters in combination with the first relationship and the second relationship to develop software for the steering system controller, and forming a calibration MAP diagram;

[0107] Obtain the vehicle's steering wheel angle α, and use the steering wheel angle α combined with the calibration MAP to calculate the inner front wheel steering angle θ 1 、Outer front wheel steering angle θ 2 、Inner rear wheel steering angle θ 3 and the outer rear wheel steering angle θ 4 .

[0108] The present application also provides a device, which includes a processor, a memory, and a computer program stored in the memory and executable by the processor, wherein when the computer program is executed by the processor, any step of the above-mentioned method for coordinated control of four wheels of a vehicle is implemented.

[0109] The present application also provides a computer-readable storage medium, on which a computer program is stored, wherein when the computer program is executed by a processor, any step of the above-mentioned method for coordinated control of four wheels of a vehicle is implemented.

[0110] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying 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 application. Unless otherwise clearly specified and limited, the terms "installed", "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 an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0111] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0112] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for coordinated control of four wheels of a vehicle, characterized in that: The steps include: Establishing a first relationship between the inner front wheel steering angle θ1 and the steering wheel angle α, so that the inner front wheel steering angle θ1 and the steering wheel angle α are in a linear relationship and have the same positive and negative signs; Establishing a second relationship between the instant center and the rear axle distance L2 and the steering wheel angle α, so that the absolute values ​​of the instant center and the rear axle distance L2 and the steering wheel angle α are in a linear relationship; Obtaining a steering wheel angle α of the vehicle, and calculating an inner front wheel steering angle θ1, an outer front wheel steering angle θ2, an inner rear wheel steering angle θ3, and an outer rear wheel steering angle θ4 respectively by using vehicle geometric parameters, steering system characteristic parameters, and the steering wheel angle α in combination with the first relationship and the second relationship; Coordinated steering angle control of all tires of the vehicle according to the inner front wheel steering angle θ1, the outer front wheel steering angle θ2, the inner rear wheel steering angle θ3 and the outer rear wheel steering angle θ4; The first relationship is: θ1 = λα Where, λ is the steering angle transmission ratio; The second relationship is: L2 = K|α| Where K is the instantaneous center forward coefficient.

2. A method for coordinated control of four wheels of a vehicle as claimed in claim 1, characterized in that: The calculation formula of the outer front wheel steering angle θ2 is calculated by using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship: Among them, B is the distance between the intersection of the left and right wheel kingpin axes and the ground, and L is the front and rear wheelbase.

3. A method for coordinated control of four wheels of a vehicle as claimed in claim 1, characterized in that: The calculation formula of the inner rear wheel steering angle θ3 is calculated by using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship: Among them, L is the front and rear wheelbase.

4. A method for coordinated control of four wheels of a vehicle as claimed in claim 1, characterized in that: The calculation formula of the outer rear wheel steering angle θ4 is calculated by using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship: Among them, B is the distance between the intersection of the left and right wheel kingpin axes and the ground, and L is the front and rear wheelbase.

5. The method for coordinated control of four wheels of a vehicle as claimed in claim 1, characterized in that: The obtaining of the steering wheel angle α of the vehicle, and using the vehicle geometric parameters, the steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship to respectively calculate the inner front wheel steering angle θ1, the outer front wheel steering angle θ2, the inner rear wheel steering angle θ3 and the outer rear wheel steering angle θ4, include: Obtain vehicle geometry parameters and steering system characteristic parameters; Utilizing the vehicle geometric parameters and the steering system characteristic parameters in combination with the first relationship and the second relationship to develop software for the steering system controller, and forming a calibration MAP diagram; The steering wheel angle α of the vehicle is obtained, and the inner front wheel steering angle θ1, the outer front wheel steering angle θ2, the inner rear wheel steering angle θ3 and the outer rear wheel steering angle θ4 are calculated respectively by using the steering wheel angle α in combination with the calibration MAP diagram.

6. A device for coordinated control of four wheels of a vehicle, characterized in that: The steps for implementing the method for four-wheel coordinated control of a vehicle as claimed in claim 1 include: A configuration module, which is used to establish a first relationship between the inner front wheel steering angle θ1 and the steering wheel angle α, so that the inner front wheel steering angle θ1 and the steering wheel angle α are in a linear relationship and have the same positive and negative directions, and is also used to establish a second relationship between the instantaneous center and the rear axle distance L2 and the steering wheel angle α, so that the instantaneous center and the rear axle distance L2 and the absolute value of the steering wheel angle α are in a linear relationship; a calculation module, which is used to obtain a steering wheel angle α of the vehicle, and to calculate an inner front wheel steering angle θ1, an outer front wheel steering angle θ2, an inner rear wheel steering angle θ3 and an outer rear wheel steering angle θ4 respectively by using vehicle geometric parameters, steering system characteristic parameters and the steering wheel angle α in combination with the first relationship and the second relationship; A control module is used to coordinately control the steering angles of all tires of the vehicle according to the inner front wheel steering angle θ1, the outer front wheel steering angle θ2, the inner rear wheel steering angle θ3 and the outer rear wheel steering angle θ4.

7. A device for coordinated control of four wheels of a vehicle, characterized in that: The device includes a processor, a memory, and a computer program stored in the memory and executable by the processor, wherein when the computer program is executed by the processor, the steps of a method for coordinated control of four wheels of a vehicle as described in any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, wherein when the computer program is executed by a processor, the steps of a method for coordinated control of four wheels of a vehicle as claimed in any one of claims 1 to 5 are implemented.

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