A vehicle dynamics-based automatic parking method and system for a semi-trailer train

Abstract

The application discloses a kind of based on vehicle dynamics semi-trailer automatic parking method and system of traction train, belong to parking technical field.Object is semi-trailer traction train, in combination with actual driving scene and environmental conditions when vehicle parking, establish parking hypothesis condition, and comb the torque dynamics relationship of trailer relative to its centroid, the torque dynamics relationship of trailer relative to saddle hinged point and the dynamics relationship of saddle hinged point, simultaneously acquire the lateral force of trailer front wheel, the lateral force of trailer rear wheel and the lateral force of trailer rear wheel, further establish its dynamics state model in combination with automobile relevant theoretical knowledge, realize the automatic parking of vehicle.Therefore, the parking method proposed in the application aims to establish the dynamics state model (in yaw plane) under the automatic parking scene of semi-trailer traction train, to guide to solve the problem that folding phenomenon is prone to occur when reversing due to open-loop instability of trailer parking system.

Description

Technical Field

[0001] The present invention belongs to the technical field of automobile driving, and relates to an automatic parking method and system for a semi-trailer traction train based on vehicle dynamics. Background Art

[0002] Vehicle dynamics are the foundation of autonomous vehicle application technology. Automatic parking is one such application. In parking scenarios, existing technology assumes the articulation angle at the saddle is close to 0°. However, when reversing, the articulation angle can reach over 30°, which is inconsistent with actual engineering scenarios.

[0003] Automatic parking technology, as an integral part of autonomous driving technology, has been widely used in the passenger car field, but it is still in the development and testing stage in the commercial vehicle field.

[0004] The existing parking system of semi-trailer traction trains is open-loop unstable and prone to folding and other phenomena, so it is necessary to establish an accurate dynamic state formula to achieve accurate automatic parking function. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem in the prior art that the parking system is open-loop unstable and prone to folding, and to provide an automatic parking method and system for a semi-trailer traction train based on vehicle dynamics.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention proposes an automatic parking method for a semi-trailer traction train based on vehicle dynamics, comprising the following steps:

[0008] Obtain the moment dynamics of the trailer relative to its center of mass, the moment dynamics of the trailer relative to the saddle hinge point, and the dynamics of the saddle hinge;

[0009] Obtain the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels based on the linear model of the tires;

[0010] The dynamic model is obtained based on the torque dynamic relationship of the trailer relative to its center of mass, the torque dynamic relationship of the trailer relative to the saddle hinge point, the dynamic relationship of the saddle hinge, the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels to achieve automatic parking.

[0011] Preferably, the moment dynamics of the trailer relative to its center of mass are related as follows:

[0012]

[0013] Among them, I z，2 Refers to the lateral moment of inertia of the semi-trailer; Refers to the angular acceleration of the angle between the longitudinal axis of the semi-trailer and the global X-axis; m2 is the mass of the semi-trailer; a y，2 Refers to the lateral acceleration of the semi-trailer's center of mass along the Y2 axis; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; F yr，2 Refers to the lateral force on the rear wheels of the semi-trailer; d r，2 Refers to the distance from the center of mass of the semi-trailer to its rear axle; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle.

[0014] Preferably, the moment dynamics of the semitrailer about its center of mass are as follows:

[0015]

[0016] Among them, I z，2 Refers to the lateral moment of inertia of the semi-trailer; Refers to the angular acceleration of the angle between the longitudinal axis of the semi-trailer and the global X-axis; Q2 refers to the lateral force acting on the semi-trailer at the saddle articulation point; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; F yr，2 Refers to the lateral force on the rear wheels of the semi-trailer; d r，2 Refers to the distance from the center of mass of the semi-trailer to its rear axle.

[0017] Preferably, the dynamic relationship at the saddle joint is as follows:

[0018] m2·a y，2 -m1·a x，1 ·sin θ-m1·a y，1 cos θ=F yr，2 +F yf，1 ·(sinδ·sinθ-cosδ·cosθ)-F yr，1 ·cos θ

[0019] Among them, m2 is the mass of the semi-trailer; a y，2 Refers to the lateral acceleration of the semi-trailer's center of mass along the Y2 axis; m1 refers to the mass of the trailer; a x，1 Refers to the longitudinal acceleration along the X1 axis at the center of mass of the trailer; θ is the articulation angle; a y，1 F is the lateral acceleration along the Y1 axis at the center of mass of the trailer; yr，2 Refers to the lateral force on the rear wheels of the semi-trailer; F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; δ refers to the turning angle of the trailer's steering wheels (front wheels); F yr，1 It refers to the lateral force acting on the rear wheels of the trailer.

[0020] Preferably, the calculation method of the articulation angle θ is as follows:

[0021]

[0022] Where θ0 is the initial articulation angle; is the angle between the trailer's longitudinal axis and the global X-axis; is the angle between the longitudinal axis of the semi-trailer and the global X-axis; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; is the time derivative of the angle between the longitudinal axis of the semitrailer and the global X-axis.

[0023] Preferably, the lateral force F of the trailer front wheel is obtained yf，1 , lateral force F on the trailer's rear wheels yr，1 and the lateral force F on the trailer's rear wheels yr，2 as follows:

[0024] F yf，1 =2·C f，1 α f，1

[0025] F yr，1 =2·C r，1 α r，1

[0026] F yr，2 =2·C r，2 α r，2

[0027] Among them, C f，1 is the lateral stiffness of the trailer's front wheel; C r，1 is the lateral stiffness of the trailer's rear wheels; C r，2 is the lateral stiffness of the rear wheel of the semi-trailer; α f，1 is the sideslip angle of the trailer's front wheels; α r，1 is the sideslip angle of the trailer's rear wheels; α r，2 is the rear wheel slip angle of the semi-trailer.

[0028] Preferably, the kinetic model is as follows:

[0029]

[0030] in, is the state quantity of the system, δ, v x，1 is the system input; the first longitudinal force Second longitudinal force The third longitudinal force m2 is the mass of the semi-trailer; d f，2Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; θ is the articulation angle; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; I z，2 Refers to the lateral moment of inertia of the semi-trailer; m1 refers to the mass of the trailer; I z，1 Refers to the trailer's lateral moment of inertia; v x，1 is the longitudinal velocity at the trailer's center of mass; v is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; y，1 is the lateral velocity at the trailer's center of mass; d r，2 Refers to the distance from the center of mass of the semi-trailer to its rear axle; F yr，2 is the lateral force of the rear wheel of the semi-trailer; F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; δ refers to the turning angle of the trailer's steering wheels (front wheels); d f，1 Refers to the distance from the center of mass of the trailer to its front axle; d q,1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; F yr,1 Refers to the lateral force on the rear wheels of the trailer; d r,1 Refers to the distance from the trailer's center of mass to its rear axle.

[0031] The present invention proposes an automatic parking system for a semi-trailer traction train based on vehicle dynamics, comprising:

[0032] a dynamic relationship acquisition module, the dynamic relationship acquisition module being used to acquire a moment dynamic relationship of the trailer relative to its center of mass, a moment dynamic relationship of the trailer relative to a saddle hinge point, and a dynamic relationship of the saddle hinge;

[0033] A vehicle lateral force acquisition module, which is used to obtain the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels based on a linear model of the tires;

[0034] A dynamic model establishment module is used to obtain a dynamic model based on the torque dynamic relationship of the trailer relative to its center of mass, the torque dynamic relationship of the trailer relative to the saddle hinge point, the dynamic relationship at the saddle hinge, the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels to achieve automatic parking.

[0035] A computer device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, the processor implements the steps of an automatic parking method for a semi-trailer traction train based on vehicle dynamics.

[0036] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for automatic parking of a semi-trailer traction train based on vehicle dynamics.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention proposes a method for automatic parking of a semi-trailer tractor train based on vehicle dynamics. This method targets a semi-trailer tractor train and, in combination with the actual driving scenario and environmental conditions during parking, establishes parking assumptions. It also analyzes the torque dynamics of the trailer relative to its center of mass, the torque dynamics of the trailer relative to the saddle hinge, and the dynamics of the saddle hinge. It also obtains the lateral forces of the trailer's front wheels, the trailer's rear wheels, and the trailer's rear wheels. Combined with relevant automotive theory, it further establishes a dynamic state model to achieve automatic parking of the vehicle. Therefore, the parking method proposed in the present invention aims to establish a dynamic state model for the automatic parking scenario of a semi-trailer tractor train, located within the yaw plane, and can address the problem of open-loop instability and susceptibility to folding in existing parking systems.

[0039] This paper proposes a single-event upset (SEV)-resistant network structure optimization system based on neural architecture search. By dividing the system into a dynamic relationship acquisition module, a vehicle lateral force acquisition module, and a dynamic model establishment module, it enables automatic parking of vehicles. The modularization concept makes each module independent, facilitating unified management of all modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 The figure is a flow chart of the automatic parking method of a semi-trailer traction train based on vehicle dynamics of the present invention.

[0042] Figure 2 This is the yaw plane force diagram of the semi-trailer tractor of the present invention.

[0043] Figure 3 This is a force analysis diagram of the saddle hinge point of the present invention.

[0044] Figure 4 This is a diagram of the automatic parking system for a semi-trailer traction train based on vehicle dynamics of the present invention. DETAILED DESCRIPTION

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0046] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0047] It should be noted that 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 or explained in subsequent drawings.

[0048] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0049] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0050] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0051] The present invention is described in further detail below with reference to the accompanying drawings:

[0052] The present invention proposes an automatic parking method for a semi-trailer traction train based on vehicle dynamics, such as Figure 1 As shown, the following steps are included:

[0053] S1. Obtain the moment dynamic relationship of the trailer relative to its center of mass, the moment dynamic relationship of the trailer relative to the saddle hinge point, and the dynamic relationship of the saddle hinge;

[0054] The moment dynamics of the trailer about its center of mass are related as follows:

[0055]

[0056] Among them, I z，2 Refers to the lateral moment of inertia of the semi-trailer; Refers to the angular acceleration of the angle between the longitudinal axis of the semi-trailer and the global X-axis; m2 is the mass of the semi-trailer; a y，2 Refers to the lateral acceleration of the semi-trailer's center of mass along the Y2 axis; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; F yr，2 Refers to the lateral force on the rear wheels of the semi-trailer; d r，2 Refers to the distance from the center of mass of the semi-trailer to its rear axle; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle.

[0057] The moment dynamics of the semitrailer about its center of mass are as follows:

[0058]

[0059] Among them, I z，2 Refers to the lateral moment of inertia of the semi-trailer; Refers to the angular acceleration of the angle between the longitudinal axis of the semi-trailer and the global X-axis; Q2 refers to the lateral force acting on the semi-trailer at the saddle articulation point; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; F yr，2 Refers to the lateral force on the rear wheels of the semi-trailer; d r，2 Refers to the distance from the center of mass of the semi-trailer to its rear axle.

[0060] The dynamic relationship of the saddle hinge is as follows:

[0061] m2·a y，2 -m1·a x，1 ·sinθ-m1·a y，1 cosθ=F yr，2 +F yf，1 ·(sinδ·sinθ-cosδ·cosθ)-F yr，1 cosθ

[0062] Among them, m2 is the mass of the semi-trailer; a y，2Refers to the lateral acceleration of the semi-trailer's center of mass along the Y2 axis; m1 refers to the mass of the trailer; a x，1 Refers to the longitudinal acceleration along the X1 axis at the center of mass of the trailer; θ is the articulation angle; a y，1 F is the lateral acceleration along the Y1 axis at the center of mass of the trailer; yr，2 Refers to the lateral force on the rear wheels of the semi-trailer; F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; δ refers to the turning angle of the trailer's steering wheels (front wheels); F yr，1 It refers to the lateral force acting on the rear wheels of the trailer.

[0063] The calculation method of the articulation angle θ is as follows:

[0064]

[0065] Where θ0 is the initial articulation angle; is the angle between the trailer's longitudinal axis and the global X-axis; is the angle between the longitudinal axis of the semi-trailer and the global X-axis; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; is the time derivative of the angle between the longitudinal axis of the semitrailer and the global X-axis.

[0066] S2. Obtaining the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels according to the linear model of the tires;

[0067] Get the lateral force F on the trailer's front wheels yf，1 , lateral force F on the trailer's rear wheels yr，1 and the lateral force F on the trailer's rear wheels yr，2 as follows:

[0068] F yf，1 =2·C f，1 α f，1

[0069] F yr，1 =2·C r，1 α r，1

[0070] F yr，2 =2·C r，2 α r，2

[0071] Among them, C f，1 is the lateral stiffness of the trailer's front wheel; C r，1 is the lateral stiffness of the trailer's rear wheels; C r，2 is the lateral stiffness of the rear wheel of the semi-trailer; α f，1 is the sideslip angle of the trailer's front wheels; α r，1 is the sideslip angle of the trailer's rear wheels; α r，2 is the rear wheel slip angle of the semi-trailer.

[0072] S3. Obtain a dynamic model based on the moment dynamic relationship of the trailer relative to its center of mass, the moment dynamic relationship of the trailer relative to the saddle hinge point, the dynamic relationship of the saddle hinge point, the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels to achieve automatic parking.

[0073] The kinetic model is as follows:

[0074]

[0075] in, is the state quantity of the system, δ, v x，1 is the system input; the first longitudinal force Second longitudinal force The third longitudinal force m2 is the mass of the semi-trailer; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; θ is the articulation angle; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; I z，2 Refers to the lateral moment of inertia of the semi-trailer; m1 refers to the mass of the trailer; I z，1 Refers to the trailer's lateral moment of inertia; v x，1 is the longitudinal velocity at the trailer's center of mass; v is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; y，1 is the lateral velocity at the trailer's center of mass; d r，2 Refers to the distance from the center of mass of the semi-trailer to its rear axle; F yr，2 is the lateral force of the rear wheel of the semi-trailer; F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; δ refers to the turning angle of the trailer's steering wheels (front wheels); d f，1 Refers to the distance from the center of mass of the trailer to its front axle; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; F yr，1 Refers to the lateral force on the rear wheels of the trailer; d r，1 Refers to the distance from the trailer's center of mass to its rear axle.

[0076] Parking assumptions:

[0077] Consider the trailer and the hitch as two rigid bodies connected by a saddle;

[0078] The trailer's front axle wheel angle is used as the lateral control input, and the left and right coaxial wheel angles are the same (bicycle model);

[0079] The wheels only move parallel to the ground, ignoring the effects of the suspension;

[0080] The normal load force of the axle is distributed to the left and right wheels, and the lateral forces of the left and right wheels on the same axis are equal;

[0081] According to the single-track characteristics of the 1 / 2 model, axial load and lateral load are applied to the front and rear axle centers respectively;

[0082] Air resistance, rolling resistance and the drag torque generated by the rotating parts of the vehicle are not considered;

[0083] When the slip angle is less than 5°, the tire cornering characteristics are considered to be in the linear range - the cornering stiffness is constant.

[0084] like Figure 2 and Figure 3 As shown, the specific implementation process is as follows:

[0085] Step 1: Trailer Dynamics

[0086] The trailer is assumed to be a bicycle model; the trailer is treated as a rigid body.

[0087] Step 1: Establish the dynamic expression of the trailer along the X1 axis in its coordinate system X1O1Y1, see formula (1):

[0088] m1·a x，1 =F xf，1 ·cosδ-F yf，1 ·sinδ+F xr，1 -P1 (1)

[0089] Where m1 refers to the mass of the trailer; a x，1 Refers to the longitudinal acceleration along the X1 axis at the center of mass of the trailer; F xf，1 Refers to the longitudinal force on the front wheels of the trailer, parallel to the wheel plane of the front wheels; δ refers to the turning angle of the steering wheel (front wheel) of the trailer; F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal direction of the wheel plane; F xr，1 Refers to the longitudinal force on the rear wheels of the trailer, parallel to the wheel plane of the rear wheels; P1 refers to the longitudinal force on the trailer at the saddle hinge point.

[0090] Step 2: Establish the dynamic expression of the trailer along the Y1 axis in its coordinate system X1O1Y1, see formula (2):

[0091] m1·a y，1 =F xf，1 ·sinδ+F yf，1 ·cosδ+F yr，1 -Q1 (2)

[0092] Where m1 refers to the mass of the trailer; Fxf，1 Refers to the longitudinal force on the front wheels of the trailer, parallel to the wheel plane; δ refers to the steering angle of the trailer's steering wheel (front wheel); F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal direction of the wheel plane; a y，1 F is the lateral acceleration along the Y1 axis at the center of mass of the trailer; yr，1 It refers to the lateral force on the rear wheels of the trailer; Q1 refers to the lateral force on the trailer at the saddle hinge point.

[0093] Step 3: Establish the dynamic expression of the moment in the trailer's coordinate system X1O1Y1, see formula (3):

[0094]

[0095] Among them, I z，1 Refers to the trailer's yaw moment of inertia; Refers to the angular acceleration of the angle between the trailer's longitudinal axis and the global X-axis; F xf，1 Refers to the longitudinal force on the front wheels of the trailer; δ refers to the turning angle of the trailer's steering wheel (front wheel); F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal direction of the wheel plane; d f，1 Refers to the distance from the center of mass of the trailer to its front axle; F yr，1 Refers to the lateral force on the rear wheels of the trailer; d r，1 Refers to the distance from the center of mass of the trailer to its rear axle; Q1 refers to the lateral force acting on the trailer at the saddle hinge point; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle.

[0096] Step 4: Assume the trailer speed v x，1 is a constant, which means that the influence of the ground tangential force on the tire cornering characteristics is not considered. At this time, the longitudinal force F xf，1 =0, F xr，1 = 0. Equations (1) and (2) are simplified to (4) and (5) respectively:

[0097] m1·a x，1 =-F yf，1 ·sinδ-P1 (4)

[0098] Where m1 refers to the mass of the trailer; a x，1 Refers to the longitudinal acceleration along the X1 axis at the center of mass of the trailer; F yf，1 It refers to the lateral force on the front wheels of the trailer, along the normal of its wheel plane; δ refers to the turning angle of the steering wheel (front wheel) of the trailer; P1 refers to the longitudinal force on the trailer at the saddle hinge point.

[0099] m1·a y，1 =F yf，1 ·cosδ+F yr，1-Q1 (5)

[0100] Where m1 refers to the mass of the trailer; a y，1 F is the lateral acceleration along the Y1 axis at the center of mass of the trailer; yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; δ refers to the turning angle of the trailer's steering wheels (front wheels); F yr，1 It refers to the lateral force on the rear wheels of the trailer; Q1 refers to the lateral force on the trailer at the saddle hinge point.

[0101] Combining equations (3) and (5) we get:

[0102]

[0103] Among them, I z，1 Refers to the trailer's yaw moment of inertia; Refers to the angular acceleration of the angle between the longitudinal axis of the trailer and the global X-axis; m1 refers to the mass of the trailer; a y，1 Refers to the lateral acceleration along the Y1 axis at the center of mass of the trailer; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; δ refers to the turning angle of the trailer's steering wheels (front wheels); d f，1 Refers to the distance from the center of mass of the trailer to its front axle; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; F yr，1 Refers to the lateral force on the rear wheels of the trailer; d r，1 Refers to the distance from the center of mass of the trailer to its rear axle; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle.

[0104] Note: Equation (3) is the moment dynamics of the trailer relative to its center of mass; while Equation (6) is the moment dynamics of the trailer relative to the saddle hinge point.

[0105] Step 2: Semi-trailer dynamics

[0106] The semi-trailer is assumed to be a bicycle model; and the semi-trailer is regarded as a rigid body.

[0107] Step 1: Establish the dynamic expression along the X2 axis in the coordinate system X2O2Y2 for the semi-trailer, see formula (7):

[0108] m2·a x，2 =F xr，2 +P2 (7)

[0109] Among them, m2 is the mass of the semi-trailer; a x，2 Refers to the longitudinal acceleration along the X2 axis at the center of mass of the semi-trailer; F xr，2Refers to the longitudinal force on the rear wheels of the semi-trailer, parallel to the wheel plane of the rear wheels; P2 refers to the longitudinal force on the semi-trailer at the saddle hinge point.

[0110] Step 2: Establish the dynamic expression along the Y2 axis in the coordinate system X2O2Y2 for the semi-trailer, see formula (8):

[0111] m2·a y，2 =F yr，2 +Q2 (8)

[0112] Among them, m2 is the mass of the semi-trailer; a y，2 Refers to the lateral acceleration along the Y2 axis at the center of mass of the semi-trailer; F yr，2 It refers to the lateral force on the rear wheels of the semi-trailer; Q2 refers to the lateral force on the semi-trailer at the saddle hinge point.

[0113] Step 3: Establish the dynamic expression of the moment in the coordinate system X2O2Y2 for the semi-trailer, see formula (9):

[0114]

[0115] Among them, I z，2 Refers to the lateral moment of inertia of the semi-trailer; Refers to the angular acceleration of the angle between the longitudinal axis of the semi-trailer and the global X-axis; Q2 refers to the lateral force acting on the semi-trailer at the saddle articulation point; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; F yr，2 Refers to the lateral force on the rear wheels of the semi-trailer; d r，2 Refers to the distance from the center of mass of the semi-trailer to its rear axle.

[0116] Step 4: Combine (8) and (9) to get:

[0117]

[0118] Among them, I z，2 Refers to the lateral moment of inertia of the semi-trailer; Refers to the angular acceleration of the angle between the longitudinal axis of the semi-trailer and the global X-axis; m2 is the mass of the semi-trailer; a y，2 Refers to the lateral acceleration of the semi-trailer's center of mass along the Y2 axis; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; F yr，2 Refers to the lateral force on the rear wheels of the semi-trailer; d r，2 Refers to the distance from the center of mass of the semi-trailer to its rear axle; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle.

[0119] Note: Equation (9) is the moment dynamics of the semitrailer relative to its center of mass; and (10) is the moment dynamics of the semitrailer relative to the saddle hinge point.

[0120] Step 3: Saddle joint dynamics

[0121] The trailer and the hitch are connected via a saddle.

[0122] Step 1: Calculation of saddle articulation angle:

[0123]

[0124] Where, θ is the articulation angle; θ0 is the initial articulation angle; is the angle between the trailer's longitudinal axis and the global X-axis; is the angle between the longitudinal axis of the semi-trailer and the global X-axis; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; is the time derivative of the angle between the longitudinal axis of the semitrailer and the global X-axis.

[0125] Step 2: The force at the saddle joint is converted into a rotation matrix:

[0126] When the trailer rotates clockwise relative to the semi-trailer, the angle it rotates is negative; when it rotates counterclockwise relative to the semi-trailer, the angle it rotates is positive.

[0127]

[0128] Among them, P2 refers to the longitudinal force acting on the semi-trailer at the saddle hinge point; Q2 refers to the lateral force acting on the semi-trailer at the saddle hinge point; P1 refers to the longitudinal force acting on the trailer at the saddle hinge point; Q1 refers to the lateral force acting on the trailer at the saddle hinge point; θ is the articulation angle.

[0129] Step 3: Convert the velocity at the saddle joint into a rotation matrix:

[0130]

[0131] Among them, v x，2 is the longitudinal velocity at the center of mass of the semitrailer; v y，2 is the lateral velocity at the center of mass of the semitrailer; is the time derivative of the angle between the longitudinal axis of the semi-trailer and the global X-axis; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; θ is the articulation angle; v x，1 is the longitudinal velocity at the center of mass of the trailer; v y，1 is the lateral velocity at the center of mass of the trailer; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle.

[0132] Combining (4), (5), (8), and (12) we get:

[0133] m2·a y，2 -m1·a x，1 ·sinθ-m1·a y，1 cosθ=F yr，2 +F yf，1 ·(sinδ·sinθ-cosδ·cosθ)-F yr，1 ·cosθ (14)

[0134] Among them, m2 is the mass of the semi-trailer; a y，2 Refers to the lateral acceleration of the semi-trailer's center of mass along the Y2 axis; m1 refers to the mass of the trailer; a x，1 Refers to the longitudinal acceleration along the X1 axis at the center of mass of the trailer; θ is the articulation angle; a y，1 F is the lateral acceleration along the Y1 axis at the center of mass of the trailer; yr，2 Refers to the lateral force on the rear wheels of the semi-trailer; F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; δ refers to the turning angle of the trailer's steering wheels (front wheels); F yr，1 It refers to the lateral force acting on the rear wheels of the trailer;

[0135] Step 4: Vehicle acceleration analysis

[0136] Step 1: Longitudinal acceleration of the trailer:

[0137]

[0138] Among them, a x，1 Refers to the longitudinal acceleration along the X1 axis at the center of mass of the trailer; is the time derivative of the longitudinal velocity at the trailer's center of mass; v y，1 is the lateral velocity at the trailer's center of mass; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis.

[0139] Step 2: Lateral acceleration of the trailer:

[0140]

[0141] Among them, a y，1 Refers to the lateral acceleration along the Y1 axis at the center of mass of the trailer; is the time derivative of the lateral velocity at the trailer's center of mass; v x，1 is the longitudinal velocity at the trailer's center of mass; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis;

[0142] Step 3: Longitudinal acceleration of the semi-trailer:

[0143]

[0144] Among them, a x，2 Refers to the longitudinal acceleration along the X2 axis at the center of mass of the semi-trailer; is the time derivative of the longitudinal velocity at the center of mass of the semitrailer; v y，2 is the lateral velocity at the center of mass of the semitrailer; is the time derivative of the angle between the longitudinal axis of the semitrailer and the global X-axis.

[0145] Step 4: Lateral acceleration of the semi-trailer:

[0146]

[0147] Among them, a y，2 Refers to the lateral acceleration of the semi-trailer's center of mass along the Y2 axis; is the time derivative of the lateral velocity at the center of mass of the semitrailer; v x，2 is the longitudinal velocity at the center of mass of the semitrailer; is the time derivative of the angle between the longitudinal axis of the semitrailer and the global X-axis.

[0148] Formula (17) is specifically expanded as follows:

[0149]

[0150] Among them, a x，2 Refers to the longitudinal acceleration along the X2 axis at the center of mass of the semi-trailer; is the time derivative of the longitudinal velocity at the trailer's center of mass; θ is the articulation angle; v x，1 is the longitudinal velocity at the trailer's center of mass; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; is the time derivative of the lateral velocity at the trailer's center of mass; v y，1 is the lateral velocity at the trailer's center of mass; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; is the second-order derivative of the angle between the trailer longitudinal axis and the global X-axis with respect to time; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; is the time derivative of the angle between the longitudinal axis of the semitrailer and the global X-axis.

[0151] Formula (18) is specifically expanded as follows:

[0152]

[0153] in, is the derivative of the articulation angle with respect to time; a y，2Refers to the lateral acceleration of the semi-trailer's center of mass along the Y2 axis; is the time derivative of the longitudinal velocity at the trailer's center of mass; θ is the articulation angle; v x，1 is the longitudinal velocity at the trailer's center of mass; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; is the time derivative of the lateral velocity at the trailer's center of mass; v y，1 is the lateral velocity at the trailer's center of mass; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; is the second-order derivative of the angle between the trailer longitudinal axis and the global X-axis with respect to time; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; It is the second-order derivative of the angle between the longitudinal axis of the semitrailer and the global X-axis with respect to time.

[0154] Step 5: Tire Dynamics

[0155] Based on the single-track characteristics of a 1 / 2 bicycle model, axial loads and lateral loads are applied to the front and rear axle centers, respectively. When the slip angle is less than 5°, the tire's cornering characteristics are considered to be in the linear range—the cornering stiffness is constant. The wheel moves only parallel to the ground, ignoring the effects of the suspension. The axle normal load is distributed to the left and right wheels, and the lateral forces on the coaxial left and right wheels are equal.

[0156] Step 1: The side slip angle of the equivalent tire in the middle of the trailer's steering axle (front axle) is:

[0157]

[0158] Among them, α f，1 is the sideslip angle of the trailer's front wheels; δ is the turning angle of the trailer's front wheels; v y，1 is the lateral velocity at the trailer's center of mass; d f，1 Refers to the distance from the trailer's center of mass to its front axle; v is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; x，1 is the longitudinal velocity at the trailer's center of mass;

[0159] Step 2: The side slip angle of the equivalent tire in the middle of the trailer drive axle (rear axle) is:

[0160]

[0161] Among them, α r，1 is the sideslip angle of the trailer's rear wheels; v y，1 is the lateral velocity at the trailer's center of mass; d r，1 Refers to the distance from the trailer's center of mass to its rear axle; v is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; x，1is the longitudinal velocity at the trailer's center of mass;

[0162] Step 3: The side slip angle of the equivalent tire in the middle of the rear axle of the semi-trailer is:

[0163]

[0164] Among them, α r，2 is the rear wheel slip angle of the semi-trailer; v y，2 is the lateral velocity at the center of mass of the semitrailer; d r，2 is the distance from the center of mass of the semi-trailer to its rear axle; v is the time derivative of the angle between the longitudinal axis of the semi-trailer and the global X-axis; x，2 is the longitudinal velocity at the center of mass of the semitrailer;

[0165] Based on (21) and (22), the following relationship is derived:

[0166]

[0167] Where L1 = d f，1 +d r，1 , is the trailer wheelbase; is the instantaneous turning radius of the trailer's center of mass;

[0168] Step 4: Assuming the tire is a linear model, its lateral forces are:

[0169] F yf，1 =2·C f，1 α f，1 (twenty four)

[0170] F yr，1 =2·C r，1 α r，1 (25)

[0171] F yr，2 =2·C r，2 α r，2 (26)

[0172] Among them, F yf，1 is the lateral force on the trailer's front wheels; F yr，1 is the lateral force on the trailer's rear wheels; F yr，2 is the lateral force of the rear wheel of the semi-trailer; C f，1 is the lateral stiffness of the trailer's front wheel; C r，1 is the lateral stiffness of the trailer's rear wheels; C r，2 is the lateral stiffness of the rear wheel of the semi-trailer; α f，1 is the sideslip angle of the trailer's front wheels; α r，1 is the sideslip angle of the trailer's rear wheels; α r，2 is the rear wheel slip angle of the semi-trailer.

[0173] Step 6: Vehicle dynamics state expression

[0174] Based on the above assumptions, the dynamic model of the semi-trailer traction train is simplified to a 3-DOF dynamic model: the lateral motion and yaw motion of the trailer, and the yaw motion at the saddle hinge point (equivalent to a 5-DOF dynamic model: the lateral motion and yaw motion of the trailer; the longitudinal motion, lateral motion, and yaw motion of the semi-trailer).

[0175] Based on the previous formula:

[0176]

[0177] in, is the state quantity of the system, δ, v x，1 is the system input;

[0178]

[0179]

[0180]

[0181]

[0182] Among them, m2 is the mass of the semi-trailer; d f，2 Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; θ is the articulation angle; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; I z，2 Refers to the lateral moment of inertia of the semi-trailer; m1 refers to the mass of the trailer; I z，1 Refers to the trailer's lateral moment of inertia; v x，1 is the longitudinal velocity at the trailer's center of mass; v is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; y，1 is the lateral velocity at the trailer's center of mass; d r，2 Refers to the distance from the center of mass of the semi-trailer to its rear axle; F yr，2 is the lateral force of the rear wheel of the semi-trailer; F yf，1 Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; δ refers to the turning angle of the trailer's steering wheels (front wheels); d f，1 Refers to the distance from the center of mass of the trailer to its front axle; d q，1 Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; F yr，1 Refers to the lateral force on the rear wheels of the trailer; d r，1 Refers to the distance from the trailer's center of mass to its rear axle.

[0183] The parameters related to the parking motion of the semi-trailer traction train are divided into two categories: structural parameters (see Table 1) and dynamic parameters (see Table 2).

[0184] Table 1 Structural parameters of semi-trailer traction train

[0185]

[0186] Table 2 Dynamic parameters of semi-trailer traction train

[0187]

[0188]

[0189] For angles, angular velocities, and angular accelerations, counterclockwise is the direction of increase;

[0190] The wheel angle and articulation angle have a wide range of variation, i.e.

[0191] The coordinate origin of the trailer local coordinate system x1O1y1 is at the center of mass of the trailer, and the coordinate origin of the semi-trailer local coordinate system x2O2y2 is at the center of mass of the semi-trailer;

[0192] Speed ​​v x，1 、v y，1 , acceleration a x，1 、a y，1 , δ, P1, Q1 are based on the coordinate system X1O1Y1; the speed v x，2 、v y，2 , acceleration a x，2 、a y，2 , P2 and Q2 are based on the coordinate system X2O2Y2; Based on the global coordinate system XOY; tire cornering force F xf，1 、F xr，1 、F xr，2 、F yf，1 、F yr，1 、F yr，2 and sideslip angle α f，1 , α r，1 , α r，2 Based on the respective tire coordinate system;

[0193] The present invention proposes an automatic parking system for a semi-trailer traction train based on vehicle dynamics, such as Figure 4 As shown, it includes a dynamic relationship acquisition module, a vehicle lateral force acquisition module and a dynamic model establishment module;

[0194] The dynamic relationship acquisition module is used to obtain the moment dynamic relationship of the trailer relative to its center of mass, the moment dynamic relationship of the trailer relative to the saddle hinge point, and the dynamic relationship of the saddle hinge;

[0195] The vehicle lateral force acquisition module is used to acquire the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels based on the linear model of the tires;

[0196] The dynamic model establishment module is used to obtain a dynamic model based on the torque dynamic relationship of the trailer relative to its center of mass, the torque dynamic relationship of the trailer relative to the saddle hinge point, the dynamic relationship at the saddle hinge, the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels to achieve automatic parking.

[0197] An embodiment of the present invention provides a terminal device, comprising: a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of each of the aforementioned method embodiments are implemented. Alternatively, when the processor executes the computer program, the functions of each module / unit in each of the aforementioned apparatus embodiments are implemented.

[0198] The computer program may be divided into one or more modules / units, which are stored in the memory and executed by the processor to accomplish the present invention.

[0199] The terminal device may be a computing device such as a desktop computer, a notebook computer, a PDA, a cloud server, etc. The terminal device may include, but is not limited to, a processor and a memory.

[0200] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0201] The memory may be used to store the computer programs and / or modules, and the processor implements various functions of the terminal device by running or executing the computer programs and / or modules stored in the memory and calling the data stored in the memory.

[0202] If the module / unit integrated in the terminal device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of each of the above-mentioned method embodiments. The computer program includes computer program code, which can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0203] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for automatic parking of a semi-trailer traction train based on vehicle dynamics, characterized in that: The steps include: Obtain the moment dynamics of the trailer relative to its center of mass, the moment dynamics of the trailer relative to the saddle hinge point, and the dynamics of the saddle hinge; Obtain the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels based on the linear model of the tires; A dynamic model is obtained based on the moment dynamic relationship of the trailer relative to its center of mass, the moment dynamic relationship of the trailer relative to the saddle hinge point, the dynamic relationship of the saddle hinge point, the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels to achieve automatic parking; The kinetic model is as follows: in, ; is the state quantity of the system, is the system input; the first longitudinal force ; Second longitudinal force ; The third longitudinal force ; is the mass of the semi-trailer; Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; is the hinge angle; Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; Refers to the lateral moment of inertia of the semi-trailer; Refers to the mass of the trailer; Refers to the trailer's yaw moment of inertia; is the longitudinal velocity at the trailer's center of mass; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; is the lateral velocity at the trailer's center of mass; Refers to the distance from the center of mass of the semi-trailer to its rear axle; is the lateral force on the rear wheels of the semi-trailer; Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; Refers to the turning angle of the trailer's front wheels; Refers to the distance from the trailer's center of mass to its front axle; Refers to the distance from the center of mass of the trailer to the hinge point of the saddle; It refers to the lateral force acting on the rear wheels of the trailer; Refers to the distance from the center of mass of the trailer to its rear axle. is the time derivative of the angle between the longitudinal axis of the semitrailer and the global X-axis.

2. The automatic parking method for a semi-trailer traction train based on vehicle dynamics according to claim 1, characterized in that: The moment dynamics of the trailer about its center of mass are related as follows: in, Refers to the lateral moment of inertia of the semi-trailer; Refers to the angular acceleration of the angle between the longitudinal axis of the semi-trailer and the global X-axis; is the mass of the semi-trailer; The center of mass of the semi-trailer is along lateral acceleration of the axis; Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; It refers to the lateral force on the rear wheels of the semi-trailer; Refers to the distance from the center of mass of the semi-trailer to its rear axle; Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle.

3. The automatic parking method for a semi-trailer traction train based on vehicle dynamics according to claim 1, characterized in that: The moment dynamics of the semitrailer about its center of mass are as follows: in, Refers to the lateral moment of inertia of the semi-trailer; Refers to the angular acceleration of the angle between the longitudinal axis of the semi-trailer and the global X-axis; Refers to the lateral force acting on the semi-trailer at the saddle articulation point; Refers to the distance from the center of mass of the semi-trailer to the articulation point of the saddle; It refers to the lateral force on the rear wheels of the semi-trailer; Refers to the distance from the center of mass of the semi-trailer to its rear axle.

4. The automatic parking method for a semi-trailer traction train based on vehicle dynamics according to claim 1, characterized in that: The dynamic relationship of the saddle hinge is as follows: in, is the mass of the semi-trailer; The center of mass of the semi-trailer is along lateral acceleration of the axis; Refers to the mass of the trailer; Refers to the direction along the center of mass of the trailer Longitudinal acceleration of the axis; is the hinge angle; Refers to the direction along the center of mass of the trailer lateral acceleration of the axis; It refers to the lateral force on the rear wheels of the semi-trailer; Refers to the lateral force on the front wheels of the trailer, along the normal to the plane of its wheels; Refers to the turning angle of the trailer's front wheels; It refers to the lateral force acting on the rear wheels of the trailer.

5. The automatic parking method for a semi-trailer traction train based on vehicle dynamics according to claim 4, characterized in that: Articulation angle The calculation method is as follows: in, is the initial articulation angle; is the angle between the trailer's longitudinal axis and the global X-axis; is the angle between the longitudinal axis of the semi-trailer and the global X-axis; is the time derivative of the angle between the trailer longitudinal axis and the global X-axis; is the time derivative of the angle between the longitudinal axis of the semitrailer and the global X-axis.

6. The automatic parking method for a semi-trailer traction train based on vehicle dynamics according to claim 1, characterized in that: Get the lateral force on the trailer's front wheels , lateral force on the trailer's rear wheels and the lateral force on the trailer's rear wheels as follows: in, is the trailer front wheel cornering stiffness; is the trailer rear wheel cornering stiffness; is the lateral stiffness of the rear wheel of the semitrailer; is the sideslip angle of the trailer’s front wheels; is the sideslip angle of the trailer's rear wheels; is the rear wheel slip angle of the semi-trailer.

7. An automatic parking system for a semi-trailer traction train based on vehicle dynamics, characterized in that: The automatic parking method for a semi-trailer traction train based on vehicle dynamics according to any one of claims 1 to 6 comprises: a dynamic relationship acquisition module, the dynamic relationship acquisition module being used to acquire a moment dynamic relationship of the trailer relative to its center of mass, a moment dynamic relationship of the trailer relative to a saddle hinge point, and a dynamic relationship of the saddle hinge; A vehicle lateral force acquisition module, which is used to obtain the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels based on a linear model of the tires; A dynamic model establishment module is used to obtain a dynamic model based on the torque dynamic relationship of the trailer relative to its center of mass, the torque dynamic relationship of the trailer relative to the saddle hinge point, the dynamic relationship at the saddle hinge, the lateral force of the trailer's front wheels, the lateral force of the trailer's rear wheels, and the lateral force of the trailer's rear wheels to achieve automatic parking.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the automatic parking method for a semi-trailer traction train based on vehicle dynamics as described in any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the automatic parking method for a semi-trailer traction train based on vehicle dynamics as described in any one of claims 1 to 6 are implemented.

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