Control method and control device for steering chassis of new energy vehicle

Abstract

The invention provides a control method and device for a steering chassis of a new energy vehicle, and the control method comprises the steps: S1, obtaining the forward speed and the steering demand angle of a current vehicle, and an actual rotation angle sensed by an angle sensor assembly, the actual rotation angle is the rotation angle of the front frame and the rear frame around a rotation point; s2, on the basis of the current driving mode of the vehicle, pre-configured vehicle steering parameters and the vehicle speed and the steering demand angle obtained in the step S1, the running speed difference between the power wheels in the driving mode is determined, or on the basis of the steering demand angle, the running speed difference between the power wheels in the driving mode is determined; and S3, according to the running speed difference determined in the S2 and the actual rotating angle obtained in the S1, the rotating speed of a driving motor in the driving mode is controlled. According to the invention, the complexity of the steering chassis can be reduced, the energy consumption during steering is saved, and the steering response speed and the steering angle of the vehicle are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, in particular to the field of agricultural vehicles, and specifically to a control method and a control device for a steering chassis of a new energy vehicle. Background Art

[0002] With the increasing shortage of oil resources and worsening environmental pollution, in order to achieve sustainable development of mankind, vehicles have higher and higher requirements for energy conservation and environmental protection. Electrification can not only solve the problem of energy conservation and emission reduction, but also drive the leap of technological development, which is an inevitable trend of social development.

[0003] In new energy vehicles, it has flexible steering, strong passability, and can adapt to work in harsh environments. In agricultural vehicles, it is particularly capable of using agricultural vehicles to mount agricultural equipment. At present, hydraulic steering systems are commonly used in articulated steering vehicles. The steering action is completed by controlling the extension and contraction of hydraulic cylinders on the left and right sides of the front and rear body hinges. However, the articulated steering system uses a hydraulic transmission mechanism, which has problems such as slow response, poor stability and high fuel consumption. In addition, the tires of articulated vehicles with traditional articulated steering are severely worn. Furthermore, the steering scheme that changes the articulation angle between the front and rear axles and the chassis has great limitations in achieving small-angle steering.

[0004] In summary, the strategy of steering based on the hydraulic cylinders on the left and right sides of the vehicle body hinge has the problems of complex structure and slow speed response. How to reduce steering energy consumption and improve steering efficiency is imminent. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a control method and a control device for a steering chassis of a new energy vehicle, which mainly solves the problem of low steering efficiency of new energy vehicles.

[0006] The objective of the present invention is achieved through the following solutions:

[0007] According to a first aspect of the present invention, a control method for a steering chassis of a new energy vehicle is provided, wherein the steering chassis comprises: a front frame, a rear frame, a front axle assembly and a rear axle assembly, wherein the front frame is connected to the front axle assembly, the rear frame is connected to the rear axle assembly, and drive motors are respectively arranged at both ends of the front axle assembly and the rear axle assembly, and the drive motors are used to drive the wheels to rotate in a fixed direction, and the steering chassis also comprises an angle sensor assembly; the front frame and the rear frame are rotatably connected, and the angle sensor assembly is used to detect the horizontal rotation angle between the front frame and the rear frame; the control method comprises:

[0008] S1. Obtain the current forward speed of the vehicle, the required steering angle, and the actual rotation angle sensed by the angle sensor component, wherein the actual rotation angle is the angle at which the front frame and the rear frame rotate around the rotation point in the forward direction; S2. Determine the driving speed difference between the powered wheels under the driving mode based on the current driving mode of the vehicle, the pre-configured vehicle steering parameters, and the vehicle speed and the required steering angle obtained in S1, or determine the driving speed difference between the powered wheels under the driving mode based on the required steering angle; S3. Control the speed of the driving motor under the driving mode according to the driving speed difference determined in S2 and the actual rotation angle obtained in S1.

[0009] In some embodiments of the present invention, the driving mode includes a front driving mode; S2 includes: S21', determining the driving speed difference between the left front wheel and the right front wheel in the front driving mode according to the steering requirement angle.

[0010] In some embodiments of the present invention, in the front driving mode, S3 includes:

[0011] S31', controlling the rotation speed of the drive motor in the front drive mode according to the driving speed difference determined in S21' and the actual rotation angle obtained in S1; wherein, the left front wheel drive motor is controlled to increase the rotation speed corresponding to the driving speed difference based on the driving speed of the front frame, and the right front wheel drive motor is controlled to reduce the rotation speed corresponding to the driving speed difference based on the driving speed of the front frame; or the left front wheel drive motor is controlled to reduce the rotation speed corresponding to the driving speed difference based on the driving speed of the front frame, and the right front wheel drive motor is controlled to increase the rotation speed corresponding to the driving speed difference based on the driving speed of the front frame.

[0012] In some embodiments of the present invention, in S21', the driving speed difference between the left front wheel and the right front wheel in the front drive mode is determined by the following rule:

[0013] The driving speed difference is determined according to the acquired steering requirement angle and by using a pre-configured conversion correspondence table between the steering requirement angle and the driving speed difference.

[0014] In some embodiments of the present invention, in S31', the rotation speed corresponding to the driving speed difference is obtained by the following rule:

[0015] Φ1=kV delta1 / D1

[0016] Among them, Φ1 represents the speed corresponding to the driving speed difference, V delta1 represents the driving speed difference, D1 represents the wheelbase between the left front wheel and the right front wheel, and k represents the rate of change of the front wheel motor driving speed.

[0017] In some embodiments of the present invention, the driving mode includes a four-wheel drive mode; S2 includes:

[0018] S21”, determining the driving speed difference between the front wheels and between the rear wheels in the four-wheel drive mode according to the pre-configured vehicle steering parameters and the vehicle speed and steering requirement angle obtained in S1, wherein the vehicle speed obtained in S1 is used as the driving speed of the front frame; determining the driving speed difference between the front wheels in the four-wheel drive mode based on the steering requirement angle; calculating the driving speed difference between the rear wheels and the driving speed of the rear frame based on the driving speed of the front frame, the steering requirement angle and the pre-configured vehicle steering parameters.

[0019] In some embodiments of the present invention, in the four-wheel drive mode, S3 includes:

[0020] S31", according to the driving speed difference of the front frame determined in S21" and the actual rotation angle obtained in S1, the rotation speed of the driving motor in the front driving mode is controlled; wherein, the left front wheel driving motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the right front wheel driving motor is simultaneously controlled to reduce the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the left rear wheel driving motor is simultaneously controlled to reduce the rotation speed corresponding to the driving speed difference of the rear frame based on the driving speed of the rear frame, and the right rear wheel driving motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the rear frame based on the current driving speed, the right front wheel driving motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the left rear wheel driving motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the rear frame based on the current driving speed, and the right rear wheel driving motor is simultaneously controlled to reduce the rotation speed corresponding to the driving speed difference of the rear frame based on the current driving speed.

[0021] In some embodiments of the present invention, in S21″, the driving speed difference between the front wheels and the rear wheels and the driving speed of the rear frame in the four-wheel drive mode are determined by the following rules:

[0022] L2×(V delta2 / D2)=V1×sin(θ)-L1×(V dalta1 / D1)×cos(θ)

[0023] V2=V1×cos(θ)+L1×(V delta1 / D1)×sin(θ)

[0024] Wherein, L2 represents the distance between the rear wheel axle and the rotation point, and the rotation point is the rotation point between the front frame and the rear frame, and V delta2represents the speed difference between the rear wheels, D2 represents the wheelbase between the left rear wheel and the right rear wheel, V1 represents the speed of the front frame, V2 represents the speed of the rear frame, θ represents the required steering angle, D1 represents the wheelbase between the left front wheel and the right front wheel, and L1 represents the distance from the front wheel axle to the rotation point.

[0025] In some embodiments of the present invention, in S31″, the rotation speed corresponding to the running speed difference of the rear frame is obtained by the following rule:

[0026] Φ2=sV delta2 / D2

[0027] Among them, Φ2 represents the speed corresponding to the speed difference of the rear frame, V delta2 Indicates V delta2 represents the driving speed difference between the rear wheels, D2 represents the wheelbase between the left rear wheel and the right rear wheel, and s represents the rate of change of the rear wheel motor drive speed.

[0028] According to a first aspect of the present invention, a control device for a steering chassis of a new energy vehicle is provided. The control device comprises a controller. The controller executes the control method provided in the first aspect of the present invention.

[0029] Compared with the prior art, the present invention has the following beneficial effects: the present invention can reduce the complexity of the steering chassis and save energy consumption during steering by eliminating the extension and retraction of the hydraulic cylinders on the left and right sides of the hinge of the front frame and the rear frame; furthermore, the steering of the vehicle is controlled by directly acting on the rotation speed difference between the power wheels through the steering demand angle (preferably through the horizontal rotation angle between the front frame and the rear frame), which can improve the steering response speed and steering angle of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The embodiments of the present invention are further described below with reference to the accompanying drawings:

[0031] Figure 1 A structural schematic diagram of a steering chassis for a new energy vehicle is provided for an embodiment of the present invention;

[0032] Figure 2 A schematic flow chart of a control method for a steering chassis of a new energy vehicle is provided for an embodiment of the present invention;

[0033] Figure 3 A simplified structural schematic diagram of a steering chassis for a new energy vehicle is provided for an embodiment of the present invention;

[0034] Figure 4 A speed decomposition schematic diagram of a steering chassis of a new energy vehicle is provided for an embodiment of the present invention.

[0035] Description of the reference numerals: rear frame 1; front frame 2; rotation point 3 between the rear frame and the front frame; front axle assembly 4; rear axle assembly 5; wheel 6; drive motor 7; angle sensor assembly 8. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] As mentioned in the background technology, "the steering strategy based on the hydraulic cylinders on the left and right sides of the vehicle body hinge has the problems of complex structure and slow speed response." In order to solve these problems, the present invention reduces the complexity of the vehicle steering structure by adjusting the structure of the vehicle chassis and reducing the hydraulically driven steering structures such as the hydraulic push rods in the steering. On this basis, in order to obtain a better steering radius and response efficiency, the steering demand angle utilizes vehicle steering parameters such as the horizontal rotation point between the front frame and the rear frame, and directly acts on the speed difference between the power wheels to control the steering of the vehicle, so as to improve the flexibility and efficiency of the vehicle steering.

[0038] In order to better illustrate the implementation process of the present invention, the following is first introduced about a steering chassis of a new energy vehicle provided by the present invention. Figure 1 As shown, the steering chassis includes: a front frame 2, a rear frame 1, a front axle assembly 4 and a rear axle assembly 5, wherein the front frame 2 is connected to the front axle assembly 4, the rear frame 1 is connected to the rear axle assembly 5, and drive motors 7 are respectively provided at both ends of the front axle assembly 4 and the rear axle assembly 5. The drive motor 7 is used to drive the wheels 6 to rotate in a fixed direction. The steering chassis also includes an angle sensor assembly 8; the front frame and the rear frame are rotatably connected, and the angle sensor assembly is used to detect the horizontal rotation angle between the front frame and the rear frame.

[0039] It should be noted that, in this embodiment, the drive motor 7 is used to drive the wheel 6 to rotate in a fixed direction, and it is preferred that the wheel is connected to the axis of the front axle assembly in a non-rotating manner; the drive motor 7 can be connected to the wheel through a reducer. In this embodiment, the front frame 2 and the rear frame 1 perform steering operations through the rotation point 3 between the rear frame and the front frame. The rotation point 3 can be connected by means of articulation or the like. The hardware units such as batteries required during the use of the vehicle are selected based on the understanding of new energy vehicles by those skilled in the art, and will not be repeated here.

[0040] In order to improve the steering efficiency of the vehicle, based on the above vehicle chassis, according to one embodiment of the present invention, a control method for the steering chassis of a new energy vehicle is provided. Figure 2As shown, the control method includes: S1, obtaining the current forward speed of the vehicle, the required steering angle and the actual rotation angle sensed by the angle sensor component, wherein the actual rotation angle is the angle at which the front frame and the rear frame rotate around the rotation point in the forward direction; S2, determining the driving speed difference between the power wheels under the driving mode based on the current driving mode of the vehicle, the pre-configured vehicle steering parameters and the vehicle speed and the required steering angle obtained in S1, or determining the driving speed difference between the power wheels under the driving mode based on the steering required angle; S3, controlling the speed of the driving motor under the driving mode according to the driving speed difference determined in S2 and the actual rotation angle obtained in S1.

[0041] It should be noted that the pre-configured vehicle steering parameters include the distance between the rear wheel axle and the rotation point, the wheelbase between the left rear wheel and the right rear wheel, the wheelbase between the left front wheel and the right front wheel, the distance between the front wheel axle and the rotation point, etc. The understanding of the pre-configured vehicle steering parameters is the adaptive understanding of the parameters used in the basic control method, and the use of these parameters will be further explained below. In this embodiment, the parameters such as the steering demand angle are directly applied to the driving speed difference between the power wheels, which can greatly improve the steering efficiency and flexibility on the basis of expanding the steering angle by using the turning point 3 between the rear frame and the front frame. The driving speed difference between the power wheels in the driving mode can be well adapted to the user's experience of steering efficiency. For example, in the front-wheel drive or rear-wheel drive mode, the steering is faster and more comfortable; in the four-wheel drive mode, the steering response is faster and more flexible. The control method provided by the present invention will be explained in detail below.

[0042] In step S1 of the control method provided by the present invention, the forward speed of the current vehicle, the required steering angle, and the actual rotation angle sensed by the angle sensor assembly are obtained. The forward speed of the current vehicle (which can be understood as the front part in the forward direction of the vehicle, such as the driving speed of the front frame) can be directly obtained by the vehicle controller and other units; the required steering angle is generated according to the steering wheel and its auxiliary structures of the vehicle; the angle sensor assembly can sense the actual rotation angle. It should be noted that the parameter acquisition process in this embodiment is known to those skilled in the art and will not be repeated here.

[0043] The speed control process of the front drive mode and the four-wheel drive mode in the preferred drive mode of the embodiment of the present invention is explained.

[0044] In the front drive mode, according to one embodiment of the present invention, S2 in the control method includes: S21', determining the driving speed difference between the left front wheel and the right front wheel in the front drive mode according to the steering demand angle. Preferably, the driving speed difference is determined according to the acquired steering demand angle and a pre-configured conversion correspondence table between the steering demand angle and the driving speed difference. The steering demand angle and the driving speed difference are a relationship table obtained based on multiple statistical experiments, and the use of the relationship table can improve the comfort of steering control. Further, the rotation speed corresponding to the driving speed difference is obtained by the following rules:

[0045] Φ1=kV delta1 / D1

[0046] Among them, Φ1 represents the speed corresponding to the driving speed difference, V delta1 represents the driving speed difference, D1 represents the wheelbase between the left front wheel and the right front wheel, and k represents the rate of change of the front wheel motor driving speed.

[0047] It should be noted that when the vehicle steering control is performed through the driving speed difference, the vehicle steering angle target (steering required angle) can be quickly determined through the driving speed difference; in the process of controlling the wheel speed, the speed change ratio of the rotation speed of each drive motor is operated according to the set ratio. In order to simplify the control process, the vehicle speed change on the same axis is set to k = 0.5, which can quickly establish the increase or decrease of the rotation speed of the drive wheel.

[0048] In the front drive mode, the control method S3 includes: S31', according to the driving speed difference determined in S21' and the actual rotation angle obtained in S1, control the speed of the driving motor in the front drive mode; wherein, the left front wheel driving motor is controlled to increase the speed corresponding to the driving speed difference based on the driving speed of the front frame, and the right front wheel driving motor is controlled to reduce the speed corresponding to the driving speed difference based on the driving speed of the front frame; or the left front wheel driving motor is controlled to reduce the speed corresponding to the driving speed difference based on the driving speed of the front frame, and the right front wheel driving motor is controlled to increase the speed corresponding to the driving speed difference based on the driving speed of the front frame. It should be noted that when k = 0.5, the parameters of the driving motor are preferably the same, which can improve the control accuracy and reduce the control difficulty; the increase or decrease of the speed of the left front wheel driving motor is determined according to the steering requirement angle. For example, when the vehicle turns left, the speed of the left front wheel driving motor is reduced, and the speed of the right front wheel driving motor is increased. The speed reduction and increase are half of the driving speed difference, which can reduce the control difficulty and improve the steering comfort.

[0049] In the four-wheel drive mode, the front wheels and the rear wheels can be used together as power wheels to further reduce the steering delay time of the vehicle. In the four-wheel drive mode, S2 in the control method includes: S21", according to the pre-configured vehicle steering parameters and the vehicle speed and steering requirement angle obtained in S1, determine the driving speed difference between the front wheels and between the rear wheels in the four-wheel drive mode, wherein the vehicle speed obtained in S1 is used as the driving speed of the front frame; determine the driving speed difference between the front wheels in the four-wheel drive mode based on the steering requirement angle; calculate the driving speed difference between the rear wheels and the driving speed of the rear frame based on the driving speed of the front frame, the steering requirement angle and the pre-configured vehicle steering parameters.

[0050] Correspondingly, the S3 in the control method includes: S31", controlling the rotation speed of the drive motor in the front drive mode according to the driving speed difference of the front frame determined in the S21" and the actual rotation angle obtained in the S1; wherein, the left front wheel drive motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the right front wheel drive motor is simultaneously controlled to reduce the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the left rear wheel drive motor is simultaneously controlled to reduce the rotation speed corresponding to the driving speed difference of the rear frame based on the driving speed of the rear frame, and the right rear wheel drive motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the rear frame based on the current driving speed, the right front wheel drive motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the left rear wheel drive motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the rear frame based on the current driving speed, and the right rear wheel drive motor is simultaneously controlled to reduce the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the right front wheel drive motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the left rear wheel drive motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the rear frame based on the current driving speed, and the right rear wheel drive motor is simultaneously controlled to reduce the rotation speed corresponding to the driving speed difference of the rear frame based on the current driving speed.

[0051] Furthermore, in S21″, the driving speed differences between the front wheels and the rear wheels and the driving speed of the rear frame in the four-wheel drive mode are determined by the following rules:

[0052] L2×(V delta2 / D2)=V1×sin(θ)-L1×(V dalta1 / D1)×cos(θ)

[0053] V2=V1×cos(θ)+L1×(V delta1 / D1)×sin(θ)

[0054] Wherein, L2 represents the distance between the rear wheel axle and the rotation point, and the rotation point is the rotation point between the front frame and the rear frame, and V delta2represents the speed difference between the rear wheels, D2 represents the wheelbase between the left rear wheel and the right rear wheel, V1 represents the speed of the front frame, V2 represents the speed of the rear frame, θ represents the required steering angle, D1 represents the wheelbase between the left front wheel and the right front wheel, and L1 represents the distance from the front wheel axle to the rotation point.

[0055] In S31", the rotation speed corresponding to half of the running speed difference of the rear frame is obtained by the following rule:

[0056] Φ2=sV delta2 / D2

[0057] Among them, Φ2 represents the speed corresponding to the speed difference of the rear frame, V delta2 Indicates V delta2 represents the driving speed difference between the rear wheels, D2 represents the wheelbase between the left rear wheel and the right rear wheel, and s represents the rate of change of the rear wheel motor drive speed.

[0058] It should be noted that after the speed difference between the rear wheels on the rear frame is determined, when determining the corresponding rates of speed change of the rear wheels and the front wheels, they can be allocated according to the set ratio to achieve a balance between steering comfort and efficiency. Preferably, S is set to 0.5 and K of the front vehicle is set to 0.5.

[0059] In order to better illustrate the mutual relationship between speeds in the present invention, a speed model is further explained below.

[0060] like Figure 3 As shown, the vehicle chassis is equivalent to a concise mathematical model. D represents the wheelbase, preferably the wheelbase D1 between the left front wheel and the right front wheel is the same as the wheelbase D2 between the left rear wheel and the right rear wheel; the hinge point (sometimes also called the rotation point) is abstracted as point Ob, the front axle is abstracted as Oc, the rear axle is abstracted as Oa, L1 represents the distance between the front wheel axle and the rotation point, and L2 represents the distance between the rear wheel axle and the rotation point.

[0061] Taking the four-wheel drive mode as an example, the speed is decomposed for the hinge point Ob. Figure 4 As shown,

[0062] The front frame has a vertical speed in the travel direction V3 = L1 × Φ1 = L1 × (Vde lta1 / D);

[0063] The speed of the rear frame in the direction perpendicular to the speed of the rear frame V4 = V1 × sin (θ) - V3 × cos (θ)

[0064] The speed of the rear frame V2 = V1 × cos(θ) + V3 × sin(θ)

[0065] For the second half, V4 = L2 × Φ2 = L2 × (Vde lta2 / D)

[0066] Among them, Φ1=kVde lta1 / D; Φ2=SVde lta2 / D. Φ2 represents the speed corresponding to half the speed difference of the rear frame, V delta2 Indicates V delta2 represents the speed difference between the rear wheels; L2 represents the distance between the rear wheel axle and the rotation point, the rotation point is the rotation point between the front frame and the rear frame, V delta2 represents the speed difference between the rear wheels, D2 represents the wheelbase between the left rear wheel and the right rear wheel, V1 represents the speed of the front frame, V2 represents the speed of the rear frame, θ represents the required steering angle, D1 represents the wheelbase between the left front wheel and the right front wheel, L1 represents the distance from the front wheel axle to the rotation point; s represents the rate of change of the rear wheel motor drive speed, and k represents the rate of change of the front wheel motor drive speed.

[0067] Then the front frame differential relationship is:

[0068] L2×(V delta2 / D)=V1×s in(θ)L1×(V dalta1 / D)×cos(θ)......................(1)

[0069] The relationship between the front and rear frame speeds is:

[0070] V2=V1×cos(θ)+L1×(Vde lta1 / D)×s in(θ).............(2)

[0071] Among the unknown quantities above, V delta1 V is determined by the steering wheel angle, V1 is determined by the throttle opening, and V delta2 and V2.

[0072] In the control method, the speed of the drive motor in the driving mode is controlled according to the driving speed difference determined in S2 and the actual rotation angle obtained in S1. Specifically, when the response speed of the drive motor is fast, the steering delay of the vehicle can be reduced; when the actual rotation angle reaches the required steering angle, the driving speed difference of the drive motor of each power wheel is zero, in other words, the speed difference of the power wheels is zero.

[0073] In the front-drive mode, when the speed V1 of the front frame is determined, at the selected rate of change, the two front wheels can be controlled to accelerate and decelerate respectively based on the speed V1 of the front frame, and when the actual turning angle reaches the required turning angle, the two front wheels are driven at the same speed V1. Preferably, the coefficients of the control change rates of the two front wheels are preferably 0.5.

[0074] In the four-wheel drive mode, when the speed V1 of the front frame is determined, the running speed difference V between the rear wheels of the rear part can be calculated. delta2 and the running speed V2 of the rear frame, at the selected rate of change, the two front wheels can be controlled to accelerate and decelerate respectively based on the speed V1 of the front frame; the two rear wheels can be controlled to accelerate and decelerate respectively based on the speed V2 of the rear frame; when the actual turning angle reaches the required turning angle, the two front wheels are driven at the same speed V1, and the two rear wheels are driven at the same speed V2. Preferably, the coefficients of the control change rates of the two front wheels are preferably 0.5, and the coefficients of the control change rates of the two rear wheels are preferably 0.5.

[0075] The present invention can improve the steering response speed of the vehicle by converting the steering demand angle into the speed control of each power wheel, and can improve the steering flexibility of the vehicle by combining the hinge point between the front frame and the rear frame for steering; it should be said that when the speed response of the power wheel is fast enough, the steering demand angle is correlated with the speed of the power wheel. Furthermore, the names of the front wheel, front frame, etc. are only for the convenience of explanation. According to the forward direction of the vehicle, the front wheel and the front frame are in the front, and the corresponding parts are the rear frame and the rear wheel.

[0076] The present invention may be a system, an apparatus, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present invention.

[0077] Computer readable storage medium can be a tangible device that holds and stores instructions used by an instruction execution device. Computer readable storage medium can include, for example, but is not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. More specific examples (non-exhaustive list) of computer readable storage medium include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, for example, a punch card or a protruding structure in a groove on which instructions are stored, and any suitable combination thereof.

[0078] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A control method for a steering chassis of a new energy vehicle, the steering chassis comprising: A front frame, a rear frame, a front axle assembly and a rear axle assembly, wherein the front frame is connected to the front axle assembly, the rear frame is connected to the rear axle assembly, and both ends of the front axle assembly and the rear axle assembly are respectively provided with drive motors, and the drive motors are used to drive the wheels to rotate in a fixed direction. It is characterized in that the steering chassis also includes an angle sensor assembly; the front frame and the rear frame are rotatably connected, and the angle sensor assembly is used to detect the horizontal rotation angle between the front frame and the rear frame; the control method includes: S1, obtaining the current forward speed of the vehicle, the required steering angle, and the actual rotation angle sensed by the angle sensor assembly, wherein the actual rotation angle is the angle at which the front frame and the rear frame rotate around the rotation point in the forward direction; S2, determining the driving speed difference between the powered wheels in the driving mode based on the current driving mode of the vehicle, the pre-configured vehicle steering parameters, and the vehicle speed and the steering requirement angle obtained in S1, or determining the driving speed difference between the powered wheels in the driving mode based on the steering requirement angle; S3. Control the rotation speed of the driving motor in the driving mode according to the driving speed difference determined in S2 and the actual rotation angle obtained in S1.

2. The control method according to claim 1, characterized in that: The driving mode includes a front driving mode; S2 includes: S21′, determining the driving speed difference between the left front wheel and the right front wheel in the front drive mode according to the steering requirement angle.

3. The control method according to claim 2, characterized in that: The S3 includes: S31', controlling the rotation speed of the drive motor in the front drive mode according to the driving speed difference determined in S21' and the actual rotation angle obtained in S1; wherein, the left front wheel drive motor is controlled to increase the rotation speed corresponding to the driving speed difference based on the driving speed of the front frame, and the right front wheel drive motor is controlled to reduce the rotation speed corresponding to the driving speed difference based on the driving speed of the front frame; or the left front wheel drive motor is controlled to reduce the rotation speed corresponding to the driving speed difference based on the driving speed of the front frame, and the right front wheel drive motor is controlled to increase the rotation speed corresponding to the driving speed difference based on the driving speed of the front frame.

4. The control method according to claim 2, characterized in that: In the step S21', the driving speed difference between the left front wheel and the right front wheel in the front drive mode is determined by the following rule: The driving speed difference is determined according to the acquired steering requirement angle and by using a pre-configured conversion correspondence table between the steering requirement angle and the driving speed difference.

5. The control method according to claim 4, characterized in that: In the S31', the rotation speed corresponding to the driving speed difference is obtained by the following rule: Φ1=kV delta1 / D1 Among them, Φ1 represents the speed corresponding to the driving speed difference, V delta1 represents the driving speed difference, D1 represents the wheelbase between the left front wheel and the right front wheel, and k represents the rate of change of the front wheel motor driving speed.

6. The control method according to claim 1, characterized in that: The driving mode includes a four-wheel drive mode; S2 includes: S21”, determining the driving speed difference between the front wheels and between the rear wheels in the four-wheel drive mode according to the pre-configured vehicle steering parameters and the vehicle speed and steering requirement angle obtained in S1, wherein the vehicle speed obtained in S1 is used as the driving speed of the front frame; determining the driving speed difference between the front wheels in the four-wheel drive mode based on the steering requirement angle; calculating the driving speed difference between the rear wheels and the driving speed of the rear frame based on the driving speed of the front frame, the steering requirement angle and the pre-configured vehicle steering parameters.

7. The control method according to claim 6, characterized in that: The S3 includes: S31", according to the driving speed difference of the front frame determined in S21" and the actual rotation angle obtained in S1, controlling the rotation speed of the driving motor in the front driving mode; wherein, the left front wheel driving motor is simultaneously controlled to increase the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the right front wheel driving motor is controlled to reduce the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the left rear wheel driving motor is controlled to reduce the rotation speed corresponding to the driving speed difference of the rear frame based on the driving speed of the rear frame, and the right rear wheel driving motor is controlled to increase the rotation speed corresponding to the driving speed difference of the rear frame based on the driving speed of the rear frame; Alternatively, the left front wheel drive motor is controlled to reduce the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the right front wheel drive motor is controlled to increase the rotation speed corresponding to the driving speed difference of the front frame based on the current driving speed, the left rear wheel drive motor is controlled to increase the rotation speed corresponding to the driving speed difference of the rear frame based on the current driving speed, and the right rear wheel drive motor is controlled to reduce the rotation speed corresponding to the driving speed difference of the rear frame based on the current driving speed.

8. The control method according to claim 6, characterized in that: In S21″, the driving speed differences between the front wheels and the rear wheels and the driving speed of the rear frame in the four-wheel drive mode are determined by the following rules: L2×(V delta2 / D2)=V1×sin(θ)-L1×(V dalta1 / D1)×cos(θ) V2=V1×cos(θ)+L1×(V delta1 / D1)×sin(θ) Wherein, L2 represents the distance between the rear wheel axle and the rotation point, and the rotation point is the rotation point between the front frame and the rear frame, V delta2 represents the speed difference between the rear wheels, D2 represents the wheelbase between the left rear wheel and the right rear wheel, V1 represents the speed of the front frame, V2 represents the speed of the rear frame, θ represents the required steering angle, D1 represents the wheelbase between the left front wheel and the right front wheel, and L1 represents the distance from the front wheel axle to the rotation point.

9. The control method according to claim 8, characterized in that: In S31", the rotation speed corresponding to the running speed difference of the rear frame is obtained by the following rule: Φ2=sV delta2 / D2 Among them, Φ2 represents the speed corresponding to the speed difference of the rear frame, V delta2 Indicates V delta2 represents the driving speed difference between the rear wheels, D2 represents the wheelbase between the left rear wheel and the right rear wheel, and s represents the rate of change of the rear wheel motor drive speed.

10. A control device for a steering chassis of a new energy vehicle, characterized in that: The control device includes a controller, and the controller executes the control method according to any one of claims 1-9.

Images