CN117533395A

CN117533395A - Semitrailer steering control method, system, vehicle and storage medium

Info

Publication number: CN117533395A
Application number: CN202311689873.3A
Authority: CN
Inventors: 胡海龙; 林晓鹏; 李俊宽
Original assignee: Shenzhen Haixing Zhijia Technology Co Ltd
Current assignee: Shenzhen Haixing Zhijia Technology Co Ltd
Priority date: 2023-12-08
Filing date: 2023-12-08
Publication date: 2024-02-09

Abstract

The invention relates to the technical field of automatic driving, and discloses a semitrailer steering control method, a system, a vehicle and a storage medium, wherein the method comprises the following steps: acquiring vehicle parameters and historical state information of a semi-trailer; establishing a vehicle kinematic model based on vehicle parameters and determining the relation among the front wheel rotation angle of the tractor, the equivalent front wheel rotation angle of the trailer and the hinge angle; acquiring an equivalent front wheel corner of a current trailer, and performing curvature constraint on the equivalent front wheel corner of the current trailer based on the current road curvature in the vehicle parameters to acquire a first equivalent front wheel corner of the trailer; and carrying out compensation treatment on the hinge angle according to the vehicle parameters, the vehicle kinematic model and the historical state information to obtain a compensated hinge angle, carrying out amplitude limiting treatment on the current trailer equivalent front wheel steering angle by the compensated hinge angle and the first trailer equivalent front wheel steering angle to obtain a second trailer equivalent front wheel steering angle, and substituting the compensated hinge angle into a relation to obtain a steering angle control quantity for steering control of the semi-trailer vehicle. The invention improves the stability and accuracy of the semi-trailer control.

Description

Semitrailer steering control method, system, vehicle and storage medium

Technical Field

The invention relates to the technical field of automatic driving, in particular to a semitrailer steering control method, a semitrailer steering control system, a semitrailer steering control vehicle and a storage medium.

Background

During automatic driving control, errors of the path planning target track and the gesture are calculated based on the current position and the gesture of the vehicle, so that transverse control of the vehicle is realized. For a semitrailer, the position and the posture of the tractor can be acquired by a positioning system, such as a carrier-phase differential positioning (RTK), and the precision and the time delay are higher; whereas the position and attitude acquisition of the trailer can generally be performed in the following manner: the trailer is also provided with positioning equipment, so that the position and the posture of the trailer with low delay and high precision can be obtained; or a sensor (such as a laser radar) is shared with the sensing system, and the position and the posture of the trailer can be calculated by identifying the relative position relationship between the trailer and the tractor, namely the size of the hinge angle, through the sensing sensor arranged on the tractor. However, the position and posture of the trailer are different from that of the tractor due to the adoption of different technical schemes, so that the errors and the time delays are different, the control system can be influenced by the larger errors and the time delays, the stability of the system is reduced, and even the corresponding control function cannot be realized.

In the prior art, if the method of installing the positioning equipment on the trailer also avoids the risk of introducing larger time delay and error, the cost of the vehicle sensor is increased, so that the sensor resource is wasted, and the cost is too high to realize project landing in large-scale application; if the method of identifying the hinge angle by using a sensor shared by the sensing system (such as a laser radar) is used, the limitation of the hardware of the laser radar leads to lower data frame rate, the sensing data processing time delay exists, the hinge angle and the corresponding true value have larger error and time delay, the serious steering wheel swing easily occurs in the practical application, the steering control is unstable, and even the instability and failure of the control system occur.

In summary, when the steering control of the semi-trailer is performed by relying on the hinge angle in the related art, the problems of unstable steering control and low accuracy of the semi-trailer are easy to occur due to the delay and the error of the data acquisition of the hinge angle.

Disclosure of Invention

In view of the above, the invention provides a method, a system, a vehicle and a storage medium for controlling the steering of a semitrailer vehicle, which are used for solving the problems that the steering control of the semitrailer vehicle is unstable and the accuracy is low easily caused by the delay and the error of the acquisition data of the hinge angle when the steering control of the semitrailer vehicle is performed by the hinge angle in the prior art.

In a first aspect, the present invention provides a method for controlling steering of a semitrailer vehicle, the semitrailer vehicle comprising a tractor and a trailer, the tractor being articulated with the trailer, the method comprising:

acquiring vehicle parameters and historical state information of a semi-trailer, wherein the vehicle parameters comprise parameters related to steering control of the semi-trailer, and the historical state information is steering control parameters recorded by the semi-trailer at different historical moments;

establishing a vehicle kinematic model based on vehicle parameters, and determining a relation among front wheel turning angles of a tractor, equivalent front wheel turning angles of a trailer and a hinging angle based on the vehicle kinematic model;

acquiring a current trailer equivalent front wheel corner of a semi-trailer, and performing curvature constraint on the current trailer equivalent front wheel corner based on the current road curvature in vehicle parameters to acquire a first trailer equivalent front wheel corner;

compensating the hinge angle according to the vehicle parameters, the vehicle kinematic model and the historical state information to obtain a compensated hinge angle;

performing amplitude limiting treatment on the equivalent front wheel rotation angle of the current trailer according to the equivalent front wheel rotation angle of the first trailer and the compensation hinging angle to obtain an equivalent front wheel rotation angle of the second trailer;

substituting the equivalent front wheel turning angle and the compensation hinging angle of the second trailer into the relation to obtain turning angle control quantity, and carrying out steering control on the semitrailer based on the turning angle control quantity.

According to the invention, the delay and the error of the acquisition data of the hinge angle are considered, the prediction compensation of the hinge angle is carried out based on the vehicle parameters, the historical state information, the steering delay simulation and the semitrailer kinematics model, the accurate prediction of the hinge angle can be realized, and the problems of severe swing and unstable control of the semitrailer parking steering caused by the delay of the hinge angle are solved; the curvature constraint and amplitude limiting correction treatment are carried out on the virtual equivalent front wheel steering angle of the trailer, so that the correction amplitude of the virtual equivalent front wheel steering angle of the trailer can be adaptively adjusted under different road curvature conditions, the occurrence of folding of the semi-trailer caused by severe control and adjustment is avoided, and the stability and accuracy of semi-trailer control can be greatly improved.

In an alternative embodiment, the vehicle parameters further include tractor heading, trailer heading, tractor speed, tractor wheelbase, tractor front wheel turn angle, trailer wheelbase, articulation angle, and tractor rear wheel center to articulation point distance; the vehicle kinematics model comprises a derivative relation corresponding to the hinging angle, the tractor course and the trailer course; establishing a vehicle kinematic model based on vehicle parameters, and determining a relation of a front wheel corner of a tractor, an equivalent front wheel corner of a trailer and a hinge angle based on the vehicle kinematic model, wherein the relation comprises the following steps:

Determining a derivative relation of the articulation angle based on the tractor heading and the trailer heading;

determining a tractor heading derivative relation based on the tractor speed, the tractor wheelbase and the tractor front wheel corner;

determining a trailer course derivative relation based on the speed of the tractor, the wheelbase of the trailer, the hinge angle, the distance from the center of the rear wheel of the tractor to the hinge point, the wheelbase of the tractor and the front wheel corner of the tractor;

and determining the relation among the front wheel rotation angle of the tractor, the equivalent front wheel rotation angle of the trailer and the articulation angle based on the articulation angle derivative relation, the tractor heading derivative relation and the trailer heading derivative relation.

According to the invention, the semitrailer vehicle kinematic model is established based on vehicle parameters, and the corresponding relation among the equivalent front wheel turning angle, the hinge angle and the front wheel turning angle of the tractor is deduced based on the model, so that the theoretical basis of turning angle control quantity can be provided for the follow-up steering control of the semitrailer vehicle, and the steering control accuracy of the semitrailer vehicle is ensured to a certain extent.

In an alternative embodiment, the vehicle parameters further include a target driving path, the obtaining a current trailer equivalent front wheel corner of the semi-trailer, the curvature constraint is performed on the trailer equivalent front wheel corner based on a current road curvature in the vehicle parameters, and the obtaining a first trailer equivalent front wheel corner includes:

Selecting a target position point from a target driving path in the vehicle parameters;

determining the current equivalent front wheel corner of the trailer of the semi-trailer based on the wheelbase of the trailer and the target position point;

acquiring the current road curvature of the target position point, and performing linear interpolation based on the current road curvature to obtain an interpolation table of the road curvature and the equivalent front wheel corner of the trailer;

and determining the equivalent front wheel corner of the first trailer based on the current road curvature and the interpolation table.

According to the invention, the equivalent front wheel corner of the trailer is obtained by purely tracking any position point of the target driving path, and the equivalent front wheel corner of the trailer is subjected to curvature constraint based on the current road curvature, so that the correction amplitude of the virtual steering angle of the trailer can be adaptively adjusted under different road curvature conditions, the steering fluctuation caused by the error of the hinging angle is effectively avoided, and the stability of the steering control of the semitrailer is ensured.

In an alternative embodiment, the steering control parameters include a tractor speed, a delay correction steering angle control amount, and a tractor heading, wherein the delay correction steering angle control amount is obtained by performing delay simulation on the steering angle control amount by using a hinge angle delay.

The invention utilizes the hinge angle delay to carry out inertial link delay simulation on the rotation angle control quantity, is beneficial to solving the problem of severe swing of the semitrailer steering caused by the hinge angle delay, and ensures the accuracy of the hinge angle to a certain extent.

In an alternative embodiment, the compensation processing is performed on the hinge angle according to the vehicle parameters, the vehicle kinematic model and the historical state information to obtain a compensated hinge angle, which includes:

determining the heading of the trailer at the previous moment according to the current hinging angle of the semi-trailer and the heading of the tractor at the previous moment in the historical state information;

determining the compensated current trailer heading based on the trailer heading derivative relation, the tractor speed and the delay correction corner control quantity at the previous moment in the historical state information and the hinge angle delay;

and determining a compensated articulation angle according to the current tractor heading of the semi-trailer and the compensated current trailer heading.

The invention carries out the prediction compensation of the hinge angle based on the vehicle parameters, the historical state information, the steering delay simulation and the semitrailer kinematics model, thereby greatly improving the stability and the accuracy of semitrailer control.

In an alternative embodiment, the limiting process is performed on the equivalent front wheel steering angle of the current trailer according to the equivalent front wheel steering angle and the compensated articulation angle of the first trailer to obtain the equivalent front wheel steering angle of the second trailer, including:

adding the equivalent front wheel corner of the first trailer and the compensation hinging angle to obtain a first angle;

Subtracting the equivalent front wheel corner of the first trailer from the compensation hinging angle to obtain a second angle;

if the equivalent front wheel turning angle of the current trailer of the semi-trailer is larger than the first angle, determining that the first angle is the equivalent front wheel turning angle of the second trailer;

if the equivalent front wheel turning angle of the current trailer of the semi-trailer is smaller than the second angle, determining the second angle as the equivalent front wheel turning angle of the second trailer;

and if the equivalent front wheel turning angle of the current trailer of the semi-trailer is not smaller than the second angle and not larger than the first angle, determining that the equivalent front wheel turning angle of the current trailer is the equivalent front wheel turning angle of the second trailer.

The invention carries out amplitude limiting treatment on the equivalent front wheel steering angle of the trailer, can ensure the running stability of the vehicle, ensures that the equivalent front wheel steering angle of the trailer can adapt to various driving scenes of the semi-trailer, and improves the universality and the robustness of the semi-trailer control to a certain extent.

In an alternative embodiment, acquiring vehicle parameters of a semi-trailer comprises:

acquiring a target driving path, a tractor wheelbase, a trailer wheelbase, a distance from the center of a rear wheel of a tractor to a hinge point, a hinge angle and a hinge angle delay through an automatic driving system installed on a semi-trailer;

acquiring vehicle position information, road curvature, tractor heading, tractor front wheel turning angle and tractor speed based on preset acquisition equipment carried by a semitrailer;

And determining the heading of the trailer according to the hinging angle and the heading of the tractor.

According to the invention, the parameters related to the steering control of the semi-trailer vehicle are acquired in various modes, so that the accuracy of data can be ensured, the accuracy of the steering control quantity of the steering control of the semi-trailer is ensured, and the steering control precision of the semi-trailer vehicle is improved.

In a second aspect, the present invention provides a steering control system for a semi-trailer vehicle, the system comprising:

the data acquisition module is used for acquiring vehicle parameters and historical state information of the semi-trailer, wherein the vehicle parameters comprise parameters related to steering control of the semi-trailer, and the historical state information is steering control parameters recorded by the semi-trailer at different historical moments;

the model building module is used for building a vehicle kinematic model based on vehicle parameters and determining a relational expression of front wheel turning angles of the tractor, equivalent front wheel turning angles of the trailer and articulation angles based on the vehicle kinematic model;

the curvature constraint module is used for acquiring the current equivalent front wheel corner of the trailer of the semi-trailer, and performing curvature constraint on the current equivalent front wheel corner of the trailer based on the current road curvature in the vehicle parameters to acquire a first equivalent front wheel corner of the trailer;

the compensation processing module is used for carrying out compensation processing on the hinge angle according to the vehicle parameters, the vehicle kinematic model and the historical state information to obtain a compensated hinge angle;

The limiting processing module is used for limiting the equivalent front wheel rotation angle of the current trailer according to the equivalent front wheel rotation angle of the first trailer and the compensation hinging angle to obtain the equivalent front wheel rotation angle of the second trailer;

and the steering control module is used for substituting the equivalent front wheel steering angle and the compensation hinging angle of the second trailer into the relation to obtain steering angle control quantity, and performing steering control on the semitrailer based on the steering angle control quantity.

According to the semitrailer steering control system, the prediction compensation of the hinge angle is obtained based on the vehicle parameters, the historical state information, the steering delay simulation and the semitrailer kinematic model, and the curvature constraint and the amplitude limiting correction processing are carried out on the equivalent front wheel steering angle of the trailer, so that the problems of delay and error of the hinge angle can be effectively solved, and the stability and the accuracy of semitrailer control are improved.

In a third aspect, the present invention provides a vehicle comprising a controller comprising: the device comprises a memory and a processor, wherein the memory and the processor are in communication connection, the memory stores computer instructions, and the processor executes the computer instructions so as to execute the steering control method of the semitrailer in the first aspect or any corresponding implementation mode.

In a fourth aspect, the present invention provides a computer readable storage medium having stored thereon computer instructions for causing a computer to execute a method for controlling steering of a semitrailer vehicle according to the first aspect or any one of its corresponding embodiments.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a method of controlling steering of a semi-trailer in accordance with an embodiment of the present invention;

FIG. 2 is a flow chart diagram of a method of steering a second half of a hanging vehicle in accordance with an embodiment of the present invention;

FIG. 3 is a schematic representation of vehicle parameters according to an embodiment of the present invention;

FIG. 4 is a schematic flow chart of a steering control method of a semitrailer according to an embodiment of the present invention;

FIG. 5 is a block diagram of a steering control system for a semi-trailer in accordance with an embodiment of the present invention;

Fig. 6 is a schematic structural view of a controller of a vehicle according to an embodiment of the present invention.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the embodiments of the present invention, a method embodiment for controlling steering of a semitrailer is provided, and it should be noted that the steps illustrated in the flowchart of the accompanying drawings may be performed in a computer system such as a set of computer executable instructions, and that although a logical sequence is illustrated in the flowchart, in some cases, the steps illustrated or described may be performed in a different order than that illustrated herein.

In this embodiment, a method for controlling steering of a semitrailer is provided, fig. 1 is a schematic flow chart of the method for controlling steering of a semitrailer according to an embodiment of the present invention, as shown in fig. 1, the flow chart includes the following steps:

Step S101, acquiring vehicle parameters and historical state information of a semi-trailer, wherein the vehicle parameters comprise parameters related to steering control of the semi-trailer, and the historical state information is steering control parameters recorded by the semi-trailer at different historical moments.

It should be noted that, the semitrailer vehicle in this embodiment includes a tractor and a trailer, where the tractor and the trailer are connected by a hinge, and the hinge point is located in front of the rear wheel center of the tractor; the semi-trailer vehicle is driven by the rear wheels of the tractor, and the front wheels of the tractor provide steering traction.

In this embodiment, the vehicle parameters and the historical state information of the semi-trailer and the specific acquisition mode are not limited herein, and can be adaptively adjusted according to the actual project requirements. For example, the history state information may be stored locally at the vehicle end or stored in the cloud end, and the corresponding history state information is obtained by accessing a local or cloud storage file, which is only used as an exemplary illustration and not limited thereto.

Step S102, a vehicle kinematic model is established based on vehicle parameters, and a relation among the front wheel turning angle of the tractor, the equivalent front wheel turning angle of the trailer and the hinging angle is determined based on the vehicle kinematic model.

It should be noted that, the vehicle kinematic model in this embodiment is a semitrailer classical kinematic model, which includes a derivative relation of a tractor speed, a hinge angle, a tractor heading and a trailer heading, and is used to represent a change condition of a specific parameter in a semitrailer motion process.

In this embodiment, the vehicle kinematic model is derived by performing the derivation under the non-integrity constraint in combination with the vehicle parameters based on the assumption that the vehicle does not sideslip.

Step S103, obtaining the current equivalent front wheel corner of the trailer of the semi-trailer, and carrying out curvature constraint on the current equivalent front wheel corner of the trailer based on the current road curvature in the vehicle parameters to obtain the first equivalent front wheel corner of the trailer.

In the steering control of the semi-trailer, the front wheels of the tractor provide steering traction (the trailer does not have front wheels), and in this embodiment, the trailer is considered as a separate vehicle (assuming that the trailer has front wheels and the rear wheels of the trailer do not sideslip), and the front wheel rotation angle of the tractor is referred to, so as to obtain the virtual current equivalent front wheel rotation angle of the trailer.

In practical application, due to the complexity of a vehicle driving road, under driving scenes of different road curvatures, the abnormal fluctuation of the hinge angle can cause the equivalent front wheel turning angle of the virtual current trailer to shake greatly, so that the tractor swings greatly, and the stability of the steering control of the semi-trailer is affected. The embodiment can adapt to curvature constraint of virtual equivalent front wheel corners of the current trailer, can adapt to different road curvature working conditions, reduces abnormal fluctuation of the hinge angle, avoids the problem of unstable steering running of the semitrailer, and greatly improves the robustness of steering control of the semitrailer.

And step S104, carrying out compensation processing on the hinge angle according to the vehicle parameters, the vehicle kinematic model and the historical state information to obtain a compensated hinge angle.

It should be noted that, due to the delay problem of the hinge angle, the steering angle control amount obtained by the hinge angle and the current vehicle parameters in the prior art is low in accuracy, so that the requirements of stability and accuracy of steering and running of the vehicle are difficult to be met, and a certain driving risk exists. In order to solve the problem of delay of the hinge angle, the embodiment compensates the hinge angle based on vehicle parameters, a vehicle kinematic model and historical state information to obtain an accurate hinge angle, which is beneficial to improving the accuracy of steering control of the semitrailer vehicle.

And step S105, limiting the equivalent front wheel rotation angle of the current trailer according to the equivalent front wheel rotation angle of the first trailer and the compensation hinging angle to obtain the equivalent front wheel rotation angle of the second trailer.

For an ideal driving scene, the hinge angle without error and delay can be obtained, so that the ideal equivalent front wheel corner of the trailer is obtained. However, in an actual driving scene, road working conditions are complex and changeable, certain requirements exist for the equivalent front wheel turning angle change of the trailer relative to the hinge angle change, and if the equivalent front wheel turning angle change of the trailer relative to the hinge angle change is too large, the vehicle is easy to turn and run unstably. According to the embodiment, the change boundary value is determined based on the first trailer equivalent front wheel corner and the compensation hinge angle by acquiring the change range of the trailer equivalent front wheel corner, so that the unstable state of the trailer equivalent front wheel corner when errors exist can be reduced, the rationality of the trailer equivalent front wheel corner is ensured, and the stability of semi-trailer control is improved.

And S106, substituting the equivalent front wheel rotation angle and the compensation hinge angle of the second trailer into the relation to obtain rotation angle control quantity, and carrying out steering control on the semitrailer based on the rotation angle control quantity.

In the present embodiment, the specific control manner of steering control of the semi-trailer based on the steering angle control amount is not limited herein, and is adaptively adjusted according to the actual driving requirement. For example, the steering angle control amount transmitting chassis performs vehicle steering; or converting the steering angle control amount into a steering wheel steering angle control amount and controlling the steering wheel to perform vehicle steering based on the steering wheel steering angle control amount, by way of example only and not by way of limitation.

According to the embodiment of the invention, the prediction compensation of the hinge angle is carried out based on the vehicle parameters, the historical state information, the steering delay simulation and the semitrailer kinematics model, so that the accurate prediction of the hinge angle can be realized, and the problem of severe swing and unstable control of the semitrailer parking steering caused by the delay of the hinge angle is solved; the curvature constraint and amplitude limiting correction treatment are carried out on the virtual equivalent front wheel steering angle of the trailer, so that the correction amplitude of the virtual equivalent front wheel steering angle of the trailer can be adaptively adjusted under different road curvature conditions, the occurrence of folding of the semi-trailer caused by severe control and adjustment is avoided, and the stability and accuracy of semi-trailer control are greatly improved.

In this embodiment, a steering control method for a semitrailer is provided, fig. 2 is a schematic flow chart of a steering control method for another semitrailer according to an embodiment of the present invention, as shown in fig. 2, and the flow chart includes the following steps:

in step S201, vehicle parameters of the semi-trailer and historical state information are obtained, wherein the vehicle parameters include parameters related to steering control of the semi-trailer, and the historical state information is steering control parameters recorded by the semi-trailer at different historical moments.

In the present embodiment, the vehicle parameters related to the semitrailer vehicle steering control include: target travel path, vehicle position information, road curvature, tractor wheelbase, trailer wheelbase, tractor rear wheel center to hinge point distance, tractor heading, hinge angle, trailer heading, tractor front wheel turn angle, tractor speed, and hinge angle delay. Specifically, acquiring vehicle parameters of a semi-trailer vehicle includes:

and A1, acquiring a target driving path, a tractor wheelbase, a trailer wheelbase, a distance from the center of a rear wheel of the tractor to a hinge point, a hinge angle and a hinge angle delay through an automatic driving system installed on the semi-trailer.

In one embodiment, the autopilot system includes a perception module, a planning module, and a positioning module. Specifically, the sensing module is used for identifying the relative position relation of the trailer and the tractor and outputting the size of the hinge angle, wherein the hinge angle=the heading of the tractor-the heading of the trailer; the perception module also provides a hinge angle delay. The planning module is used for providing a target driving path, which is also called a track planning result, and comprises planned track point coordinates, curvature and course information. The positioning module provides the traction vehicle position coordinates and heading information.

And step A2, acquiring vehicle position information, road curvature, tractor heading, tractor front wheel corner and tractor speed based on preset acquisition equipment carried by the semitrailer.

In this embodiment, the specific content of the preset collection device is not limited, and is set according to the actual application requirement. For example, vehicle speed information, i.e., tractor vehicle speed, is fed back through the drive-by-wire chassis; the curvature of the current vehicle running road is acquired by a curvature sensor mounted on the vehicle body, as an exemplary illustration only.

And A3, determining the heading of the trailer according to the hinging angle and the heading of the tractor.

It should be noted that the articulation angle and the tractor heading in this embodiment may be directly obtained by an autopilot system or a preset acquisition device, and then the trailer heading is determined based on an equation of articulation angle = tractor heading-trailer heading.

In one embodiment, the acquired vehicle parameters are shown in FIG. 3. Note that, in fig. 3, the semitrailer vehicle includes: the tractor and the trailer are connected in a hinged mode, and a hinged point is positioned in front of the center of the rear wheel of the tractor. Wherein Q is the center of the front wheel of the tractor, J is the hinge point, R is the center of the rear wheel of the tractor, G is the center of the rear wheel of the trailer, and L ₁ Is the wheelbase (the distance from the center of the front wheel of the tractor to the center of the equivalent rear wheel) of the tractor, L ₂ Is the wheelbase (the distance from the hinging point to the center of the equivalent rear wheel of the trailer) of the trailer, L _a Distance theta between center of rear wheel of tractor and hinge point ₀ Is the heading and theta of the tractor ₁ Is the heading of the trailer (the articulation angle is the included angle formed by the tractor and the trailer, and the articulation angle)Tow vehicle heading θ ₀ TrailerHeading theta ₁ )、δ _f For front wheel corner of tractor and v ₀ Is the speed of the tractor.

In this embodiment, the steering control parameters include a tractor speed, a delay correction steering angle control amount, and a tractor heading, where the delay correction steering angle control amount is obtained by performing delay simulation on the steering angle control amount by using a hinge angle delay.

It should be noted that, the steering control method of the semitrailer according to the present embodiment is executed in one control period, and may include a plurality of control periods. Because the time delay of the hinge angle needs to calculate the current hinge angle based on the historical state information, the current state needs to be recorded into the historical state information at the end of each control period TC, and the cycle number k needing to be recorded needs to meet the relation of k multiplied by TC not less than T, wherein T is the time delay of the hinge angle. It should be noted that the articulation angle delay T is provided directly by the perception module of the autopilot system, in particular in the order of hundreds of milliseconds, for example 120ms.

Specifically, the information to be recorded includes: vehicle speed information (v) _m-k ,…,v _m-1 ,v _m ) Wherein v is _m Tractor speed for the last control period, and so on (the same applies below); delay correction corner control quantity(s) _m-k ,…,s _m-1 ,s _m ) Course of tractor (theta) _m-k ,…,θ _m-1 ,θ _m ). In the embodiment, the rotation angle control quantity is subjected to delay simulation by utilizing the hinge angle delay to obtain the delay correction rotation angle control quantity s _his The calculation method comprises the following steps: in each control cycle, the steering control amount s of the front wheels of the tractor in the steering control method of the semitrailer of the present embodiment is set _r And obtaining the product after delay correction. The method aims at simulating the delay response of an actual vehicle, and presumes that the control quantity of the rotation angle after delay correction of the current control period needing to be recorded with historical data is s _his The following steps are:

wherein TS is an inertial link time constant, and the specific value is based on the actual resultsThe steering delay performance of the vehicle is adaptively adjusted when in use, and the adjustment requirement comprises enabling the delay simulation to conform to the actual vehicle control characteristics. Correcting the delay s _his At last, recording the steering angle control quantity of the front wheel of the tractor, which is responded by the vehicle in the current period, in the history data record list; and other historical data records do not need to be subjected to delay simulation, and the state records fed back by the sensors carried by the vehicle body can be used. It should be noted that the above recorded history state information is stored for use at a later time.

Step S202, a vehicle kinematic model is established based on vehicle parameters, and a relation among the front wheel rotation angle of the tractor, the equivalent front wheel rotation angle of the trailer and the articulation angle is determined based on the vehicle kinematic model.

In this embodiment, the vehicle parameters further include a tractor heading, a trailer heading, a tractor speed, a tractor wheelbase, a tractor front wheel turn angle, a trailer wheelbase, a articulation angle, and a tractor rear wheel center to articulation point distance; the vehicle kinematics model comprises a derivative relation corresponding to the articulation angle, the tractor heading and the trailer heading.

Specifically, the step S202 includes:

step S2021, determining a derivative relation of articulation angle based on the tractor heading and the trailer heading.

In this embodiment, the articulation angle derivative relation describes the rate of change of the articulation angle.

Step S2022, determining a tractor heading derivative relation based on the tractor speed, the tractor wheelbase, and the tractor front wheel turn angle.

In this embodiment, the tractor heading derivative relationship describes the rate of change of tractor heading.

In step S2023, a trailer heading derivative relationship is determined based on the tractor speed, the trailer wheelbase, the articulation angle, the tractor rear wheel center to articulation point distance, the tractor wheelbase, and the tractor front wheel turn angle.

In this embodiment, the trailer heading derivative relationship describes the rate of change of the trailer heading.

Step S2024, determining the relationship of the tractor front wheel corner, the trailer equivalent front wheel corner, and the articulation angle based on the articulation angle derivative relationship, the tractor heading derivative relationship, and the trailer heading derivative relationship.

In one embodiment, based on the assumption that the vehicle is not sideslip, a vehicle kinematic model under non-integrity constraints is derived:

vehicle speed v of tractor ₀ Decomposing along X and Y axes to obtain corresponding vehicle speeds, wherein,for the speed component of the tractor in the X-axis direction, a speed component of the tractor in the X-axis direction>For the velocity component of the tractor in the Y-axis direction, etc>Is a hinge angle->Derivative of->Derivative for the heading of the tractor +.>Is the derivative of the heading of the trailer.

Considering the trailer as a separate vehicle, determining the front wheel angle delta of the tractor assuming that the trailer equivalent front wheel angle gamma exists _f Equivalent front wheel angle gamma and articulation angle of trailerThe relation of (2) is:

step S203, obtaining the current equivalent front wheel corner of the trailer of the semi-trailer, and carrying out curvature constraint on the current equivalent front wheel corner of the trailer based on the current road curvature in the vehicle parameters to obtain the first equivalent front wheel corner of the trailer.

In this embodiment, the vehicle parameters further include a target travel path, which is acquired by the planning module of the autopilot system.

Specifically, the step S203 includes:

step S2031, selecting a target position point from the target travel paths in the vehicle parameters.

In the present embodiment, referring to fig. 3, d (x _t ,y _t ) Is a target position point of the target driving path (also called a planned trajectory).

Step S2032, determining a current trailer equivalent front wheel corner of the semi-trailer based on the trailer wheelbase and the target location point.

In this embodiment, the value of the equivalent front wheel rotation angle γ of the trailer can be obtained based on pure tracking or other algorithms. Referring to fig. 3, taking a pure tracking algorithm as an example, a target position point D (x _t ,y _t ) Let alpha be the angle formed by the connecting line of the target point and the rear wheel center of the trailer and the direction of the trailer body, L _d For its distance, the current trailer equivalent front wheel steering angle γ is:

step S2033, obtaining the current road curvature of the target location point, and performing linear interpolation based on the current road curvature to obtain an interpolation table of the road curvature and the equivalent front wheel corner of the trailer.

In this embodiment, the current road curvature of the target location point may be obtained by a planning module of the autopilot system or based on a curvature sensor onboard the vehicle.

Step S2034, determining an equivalent front wheel turning angle of the first trailer based on the current road curvature and the interpolation table.

In a specific embodiment, curvature constraint is performed on the current trailer equivalent front wheel turning angle γ in step S2032, and the road curvature at the target position point D is obtained by the planning module; and taking the curvature as an anchoring value to perform linear interpolation to obtain a constraint value gamma of the equivalent front wheel rotation angle gamma of the current trailer _limit The steering fluctuation caused by the error of the hinge angle is avoided, the influence can be corrected when the linear road section is steered greatly to realize the stability of control, and the correction amount required by the acquisition of the curve bending can be ensured. The interpolation table is shown in table 1.

TABLE 1

ρ ₀	ρ ₁	…	ρ _n-1	ρ _n
					γ _{limit_1}	γ _{limit_2}	…	γ _{limit_n-1}	γ _{limit_n}

Note that γ in the interpolation table _{limit_1} The values of the line and the like are determined in advance through debugging calibration, and when the vehicle is in actual use, if the current road curvature rho of the target position point is fullFoot ρ _n-1 ≤ρ≤ρ _n The equivalent front wheel angle gamma of the first trailer _limit By passing throughAnd (5) determining a formula.

According to the embodiment of the invention, the equivalent front wheel corner of the trailer is obtained by purely tracking any position point of the target driving path, and the equivalent front wheel corner of the trailer is subjected to curvature constraint based on the current road curvature, so that the correction amplitude of the virtual steering angle of the trailer can be adaptively adjusted under different road curvature conditions, the steering fluctuation caused by the hinge angle error is effectively avoided, and the steering control stability of the semi-trailer is ensured.

And S204, performing compensation processing on the hinge angle according to the vehicle parameters, the vehicle kinematic model and the historical state information to obtain a compensated hinge angle.

Specifically, the step S204 includes:

step S2041, determining the trailer heading at the previous moment according to the current articulation angle of the semi-trailer and the tractor heading at the previous moment in the historical state information.

In this embodiment, the current articulation angle of the semi-trailer is obtained by the sensing module of the autopilot system, and the tractor heading at the previous moment in the historical state information is obtained by accessing the local storage record of the vehicle.

And step S2042, determining the compensated current trailer heading based on the trailer heading derivative relation, the tractor speed and the delay correction corner control quantity at the previous moment in the historical state information and the hinge angle delay.

Step S2043, determining a compensated articulation angle according to the current tractor heading of the semi-trailer and the compensated current trailer heading.

In one embodiment, the current articulation angle of the semi-trailer is knownThe articulation angle delay T, the compensation period number is p=T/TC (TC is a control period), and the tractor heading theta at the moment before the p period _m-p The speed of the tractor at the moment before the p period is v _m-p Delay correction rotation angle control amount s at the time immediately before p cycle _m-p ；

Obtaining the trailer heading at the moment before the p period according to the hinging angle = tractor heading-trailer heading

Obtaining compensated current trailer heading theta according to trailer heading derivative relation ₁ The method comprises the following steps:

then compensate for the articulation angleThe method comprises the following steps:

according to the embodiment of the invention, the prediction compensation of the hinge angle is carried out based on the vehicle parameters, the historical state information, the steering delay simulation and the semitrailer kinematics model, so that the stability and the accuracy of semitrailer control are greatly improved.

And step S205, limiting the equivalent front wheel rotation angle of the current trailer according to the equivalent front wheel rotation angle of the first trailer and the compensation hinging angle to obtain the equivalent front wheel rotation angle of the second trailer.

In this embodiment, clipping processing is performed on the current equivalent front wheel steering angle of the trailer by acquiring the variation range of the equivalent front wheel steering angle of the trailer, including:

and B1, adding the equivalent front wheel rotation angle of the first trailer and the compensation hinge angle to obtain a first angle.

And B2, subtracting the equivalent front wheel rotation angle of the first trailer from the compensation hinging angle to obtain a second angle.

And B3, if the equivalent front wheel turning angle of the current trailer of the semi-trailer is larger than the first angle, determining that the first angle is the equivalent front wheel turning angle of the second trailer.

And B4, if the equivalent front wheel turning angle of the current trailer of the semi-trailer is smaller than the second angle, determining the second angle as the equivalent front wheel turning angle of the second trailer.

And B5, if the current equivalent front wheel corner of the trailer of the semi-trailer is not smaller than the second angle and not larger than the first angle, determining that the current equivalent front wheel corner of the trailer is the equivalent front wheel corner of the second trailer.

In one embodiment, the first trailer equivalent front wheel rotation angle γ obtained in step S2034 is used _limit Clipping the equivalent front wheel steering angle of the trailer to obtain a second trailer equivalent front wheel steering angle gamma after clipping _real It is expressed as:

the embodiment of the invention carries out amplitude limiting treatment on the equivalent front wheel steering angle of the trailer, can ensure the running stability of the vehicle, ensures that the equivalent front wheel steering angle of the trailer can adapt to various driving scenes of the semi-trailer, and improves the universality and the robustness of the semi-trailer control to a certain extent.

And S206, substituting the equivalent front wheel rotation angle and the compensation hinge angle of the second trailer into the relation to obtain rotation angle control quantity, and performing steering control on the semi-trailer vehicle based on the rotation angle control quantity. Please refer to step S106 in the embodiment shown in fig. 1 in detail, which is not described herein.

In one embodiment, referring to fig. 4, the automatic parking control of the steering of the semitrailer vehicle includes:

Step S1, an input signal is acquired.

In this embodiment, the vehicle parameters are obtained through a planning module, a positioning module, and a sensing module of the autopilot system. In particular, the tractor positioning signal is obtained by measurement feedback of an integrated navigation positioning device mounted on the tractor, and the tractor position (x _a ,y _a ) And the heading theta of the tractor ₀ The sensing module calculates and obtains by identifying the posture of the trailerHinge angleAnd a hinge angle delay T; the planning module obtains track planning information, e.g. providing a target travel path (x ₀ ,y ₀ ),(x ₁ ,y ₁ )…(x _t ,y _t )…(x _n ,y _n ) The method comprises the steps of carrying out a first treatment on the surface of the Chassis feedback tractor speed v ₀ The method comprises the steps of carrying out a first treatment on the surface of the And the tractor wheelbase L obtained by a vehicle preset acquisition device ₁ Wheelbase L of trailer ₂ Distance L from center of rear wheel of tractor to hinge point _a Heading theta of tractor ₀ Heading theta of trailer ₁ And the front wheel angle delta of the tractor _f 。

Step S2, the history status information of a certain recorded control period TC is acquired.

The first-order inertial link simulation steering delay response is to utilize the hinge angle delay to simulate the rotation angle control quantity delay, and record the delay correction rotation angle control quantity obtained by delay simulation.

And S3, building a vehicle kinematic model and carrying out hinge angle kinematic prediction.

And S4, predicting the compensated trailer pose.

And S5, determining the kinematic relation between the hanging position and the pre-aiming point.

The step is to plan a track of the vehicle and track the track.

And S6, determining the equivalent steering angle of the vehicle.

It should be noted that this step is to obtain the equivalent front wheel rotation angle of the trailer.

And S7, the curvature of the equivalent steering angle is self-adaptively constrained.

The method is characterized in that the step is to carry out curvature constraint and amplitude limiting treatment on the equivalent front wheel corner of the trailer.

And S8, solving a reverse kinematics model.

The method comprises the step of converting the equivalent front wheel steering angle of the trailer into the steering angle of the tractor, namely substituting the equivalent front wheel steering angle of the second trailer and the compensation hinging angle into a relation to obtain the steering angle control quantity.

Step S9, acquiring steering angle of the steering wheel to perform vehicle steering control of the line control chassis.

In summary, the embodiment of the invention considers the problems of errors and delay existing in the actual application of the hinge angle, carries out the prediction compensation of the hinge angle based on a kinematic model, corrects the delay problem of the hinge angle, and avoids the problem of large-amplitude left-right swing of the tractor during steering control caused by the delay of the hinge angle; and the self-adaptive interpolation constraint of the virtual front wheel corner of the trailer is carried out based on the path curvature, so that the severe steering wheel shake caused by the error of the hinging angle is reduced, the phenomenon that the tractor and the trailer are folded and the instability is controlled is avoided.

The present embodiment also provides a steering control system for a semitrailer, which is used for implementing the foregoing embodiments and preferred embodiments, and will not be described in detail. The term "module" as used below may be a combination of software and/or hardware that implements a predetermined function. While the system described in the following embodiments is preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and contemplated.

The present invention provides a steering control system for a semitrailer vehicle, as shown in fig. 5, the system comprises:

the data acquisition module 501 is configured to acquire vehicle parameters of a semitrailer and historical state information, where the vehicle parameters include parameters related to steering control of the semitrailer, and the historical state information is steering control parameters recorded by the semitrailer at different historical moments.

The model building module 502 is configured to build a vehicle kinematic model based on vehicle parameters, and determine a relational expression of a front wheel corner of the tractor, an equivalent front wheel corner of the trailer, and a hinge angle based on the vehicle kinematic model.

The curvature constraint module 503 is configured to obtain a current trailer equivalent front wheel corner of the semi-trailer, and perform curvature constraint on the current trailer equivalent front wheel corner based on a current road curvature in vehicle parameters, so as to obtain a first trailer equivalent front wheel corner.

The compensation processing module 504 is configured to perform compensation processing on the hinge angle according to the vehicle parameter, the vehicle kinematic model and the historical state information, so as to obtain a compensated hinge angle.

And the amplitude limiting processing module 505 is configured to perform amplitude limiting processing on the current equivalent front wheel rotation angle of the trailer according to the first equivalent front wheel rotation angle and the compensated articulation angle, so as to obtain a second equivalent front wheel rotation angle of the trailer.

The steering control module 506 is configured to obtain a steering angle control amount by substituting the equivalent front wheel steering angle and the compensated articulation angle of the second trailer into a relationship, and perform steering control on the semitrailer based on the steering angle control amount.

In some alternative embodiments, the model creation module 502 includes: the system comprises a first building sub-module, a second building sub-module, a third building sub-module and a fourth building sub-module; the first building sub-module is used for determining a hinging angle derivative relation based on the tractor heading and the trailer heading; the second building sub-module is used for determining a tractor course derivative relation based on the speed of the tractor, the wheelbase of the tractor and the front wheel corner of the tractor; the third building sub-module is used for determining a trailer heading derivative relation based on the speed of the tractor, the wheelbase of the trailer, the hinging angle, the distance from the center of the rear wheel of the tractor to the hinging point, the wheelbase of the tractor and the front wheel corner of the tractor; and a fourth building sub-module for determining the relationship of the front wheel turning angle of the tractor, the equivalent front wheel turning angle of the trailer and the articulation angle based on the articulation angle derivative relationship, the tractor heading derivative relationship and the trailer heading derivative relationship.

In some alternative embodiments, the curvature constraint module 503 includes: the system comprises a first constraint sub-module, a second constraint sub-module, a third constraint sub-module and a fourth constraint sub-module; the first constraint submodule is used for selecting one target position point from a target running path in vehicle parameters; the second constraint sub-module is used for determining the current equivalent front wheel corner of the trailer of the semi-trailer based on the wheelbase of the trailer and the target position point; the third constraint sub-module is used for acquiring the current road curvature of the target position point, and performing linear interpolation based on the current road curvature to obtain an interpolation table of the road curvature and the equivalent front wheel corner of the trailer; and the fourth constraint sub-module is used for determining the equivalent front wheel corner of the first trailer based on the current road curvature and the interpolation table.

In some alternative embodiments, the compensation processing module 504 includes: the first compensation sub-module, the second compensation sub-module and the third compensation sub-module; the first compensation sub-module is used for determining the heading of the trailer at the previous moment according to the current hinging angle of the semi-trailer and the heading of the tractor at the previous moment in the historical state information; the second compensation sub-module is used for determining the compensated current trailer heading based on the trailer heading derivative relation, the tractor speed and the delay correction corner control quantity at the previous moment in the historical state information and the hinge angle delay; and the third compensation sub-module is used for determining a compensation hinging angle according to the current tractor heading of the semi-trailer and the compensated current trailer heading.

In some alternative embodiments, the clipping processing module 505 includes: the device comprises a first amplitude limiting sub-module, a second amplitude limiting sub-module, a third amplitude limiting sub-module, a fourth amplitude limiting sub-module and a fifth amplitude limiting sub-module; the first limiting submodule is used for adding the equivalent front wheel corner of the first trailer and the compensation hinge angle to obtain a first angle; the second limiting submodule is used for subtracting the equivalent front wheel corner of the first trailer from the compensation hinge angle to obtain a second angle; the third limiting submodule is used for determining that the first angle is the equivalent front wheel corner of the second trailer if the equivalent front wheel corner of the current trailer of the semi-trailer is larger than the first angle; the fourth limiting submodule is used for determining the second angle as the equivalent front wheel corner of the second trailer if the equivalent front wheel corner of the current trailer of the semi-trailer is smaller than the second angle; and the fifth limiting submodule is used for determining that the equivalent front wheel corner of the current trailer is the equivalent front wheel corner of the second trailer if the equivalent front wheel corner of the current trailer of the semi-trailer is not smaller than the second angle and not larger than the first angle.

In some alternative embodiments, the system further comprises: the vehicle parameter acquisition sub-module is used for acquiring a target driving path, a tractor wheelbase, a trailer wheelbase, a distance from the center of a rear wheel of the tractor to a hinge point, a hinge angle and a hinge angle delay through an automatic driving system installed on a semi-trailer; acquiring vehicle position information, road curvature, tractor heading, tractor front wheel turning angle and tractor speed based on preset acquisition equipment carried by a semitrailer; and determining the heading of the trailer according to the hinging angle and the heading of the tractor.

Further functional descriptions of the above respective modules are the same as those of the above corresponding embodiments, and are not repeated here.

The steering control system of the semitrailer in this embodiment is presented in the form of functional units, herein referred to as ASIC (Application Specific Integrated Circuit ) circuits, processors and memories executing one or more software or firmware programs, and/or other devices that can provide the above-described functionality.

The semitrailer steering control system provided by the embodiment of the invention can effectively solve the problems of delay and error of the hinge angle, and greatly improves the stability and accuracy of semitrailer control.

An embodiment of the present invention further provides a vehicle, the vehicle includes a controller, referring to fig. 6, fig. 6 is a schematic structural diagram of the controller provided in an alternative embodiment of the present invention, as shown in fig. 6, where the controller includes: one or more processors 10, memory 20, and interfaces for connecting the various components, including high-speed interfaces and low-speed interfaces. The various components are communicatively coupled to each other using different buses and may be mounted on a common motherboard or in other manners as desired. The processor may process instructions executing within the overall controller, including instructions stored in or on memory to display graphical information of the GUI on an external input/output device, such as a display apparatus coupled to the interface. In some alternative embodiments, multiple processors and/or multiple buses may be used, if desired, along with multiple memories and multiple memories. Also, multiple overall controllers may be connected, with each overall controller providing some of the necessary operations (e.g., as a server array, a set of blade servers, or a multiprocessor system). One processor 10 is illustrated in fig. 6.

The processor 10 may be a central processor, a network processor, or a combination thereof. The processor 10 may further include a hardware chip, among others. The hardware chip may be an application specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general-purpose array logic, or any combination thereof.

Wherein the memory 20 stores instructions executable by the at least one processor 10 to cause the at least one processor 10 to perform a method for implementing the embodiments described above.

The memory 20 may include a storage program area that may store an operating system, at least one application program required for functions, and a storage data area; the storage data area may store data created according to the use of the controller, etc. In addition, the memory 20 may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, memory 20 may optionally include memory located remotely from processor 10, which may be connected to the controller via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

Memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk, or solid state disk; the memory 20 may also comprise a combination of the above types of memories.

The controller also includes a communication interface 30 for the master control chip to communicate with other devices or communication networks.

The embodiments of the present invention also provide a computer readable storage medium, and the method according to the embodiments of the present invention described above may be implemented in hardware, firmware, or as a computer code which may be recorded on a storage medium, or as original stored in a remote storage medium or a non-transitory machine readable storage medium downloaded through a network and to be stored in a local storage medium, so that the method described herein may be stored on such software process on a storage medium using a general purpose computer, a special purpose processor, or programmable or special purpose hardware. The storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, a solid state disk or the like; further, the storage medium may also comprise a combination of memories of the kind described above. It will be appreciated that a computer, processor, microprocessor master chip or programmable hardware includes a storage component that can store or receive software or computer code that, when accessed and executed by the computer, processor or hardware, implements the methods illustrated by the embodiments described above.

Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope of the invention as defined by the appended claims.

Claims

1. A method of steering a semitrailer vehicle, the semitrailer vehicle comprising a tractor and a trailer, the tractor being articulated with the trailer, the method comprising:

establishing a vehicle kinematic model based on the vehicle parameters, and determining a relational expression of a front wheel corner of the tractor, an equivalent front wheel corner of the trailer and a hinge angle based on the vehicle kinematic model;

acquiring a current trailer equivalent front wheel corner of a semi-trailer, and performing curvature constraint on the current trailer equivalent front wheel corner based on the current road curvature in the vehicle parameters to acquire a first trailer equivalent front wheel corner;

performing compensation processing on the hinge angle according to the vehicle parameters, the vehicle kinematic model and the historical state information to obtain a compensated hinge angle;

Performing amplitude limiting treatment on the current equivalent front wheel steering angle of the trailer according to the equivalent front wheel steering angle of the first trailer and the compensation hinging angle to obtain an equivalent front wheel steering angle of a second trailer;

substituting the equivalent front wheel rotation angle of the second trailer and the compensation hinging angle into the relation to obtain rotation angle control quantity, and carrying out steering control on the semitrailer based on the rotation angle control quantity.

2. The semitrailer vehicle steering control method of claim 1, wherein the vehicle parameters further comprise a tractor heading, a trailer heading, a tractor speed, a tractor wheelbase, a tractor front wheel turn angle, a trailer wheelbase, a articulation angle, and a tractor rear wheel center to articulation point distance; the vehicle kinematics model comprises a derivative relation corresponding to a hinging angle, a tractor course and a trailer course; the establishing a vehicle kinematic model based on the vehicle parameters, and determining a relation of a front wheel corner of a tractor, an equivalent front wheel corner of a trailer and a hinge angle based on the vehicle kinematic model comprises the following steps:

and determining the relation among the front wheel turning angle of the tractor, the equivalent front wheel turning angle of the trailer and the articulation angle based on the articulation angle derivative relation, the tractor heading derivative relation and the trailer heading derivative relation.

3. The method for controlling steering of a semitrailer according to claim 2, wherein the vehicle parameters further include a target driving path, the obtaining a current trailer equivalent front wheel turning angle of the semitrailer, the curvature constraint is performed on the trailer equivalent front wheel turning angle based on a current road curvature in the vehicle parameters, and a first trailer equivalent front wheel turning angle is obtained, including:

4. The semitrailer vehicle steering control method of claim 1, wherein the steering control parameters include a tractor speed, a delay correction steering angle control amount, and a tractor heading, wherein the delay correction steering angle control amount is obtained by performing delay simulation on the steering angle control amount by using a hinge angle delay.

5. The semitrailer vehicle steering control method as recited in claim 4, wherein said compensating the articulation angle based on said vehicle parameters, said vehicle kinematic model, and said historical state information, resulting in a compensated articulation angle, comprises:

6. The method for controlling the steering of a semitrailer according to claim 3, wherein the limiting the current equivalent front wheel steering angle according to the first equivalent front wheel steering angle and the compensated articulation angle to obtain a second equivalent front wheel steering angle comprises:

7. The semitrailer vehicle steering control method according to any one of claims 1 to 6, characterized in that the acquiring vehicle parameters of the semitrailer vehicle includes:

8. A semitrailer vehicle steering control system, the system comprising:

the system comprises a data acquisition module, a control module and a control module, wherein the data acquisition module is used for acquiring vehicle parameters and historical state information of a semi-trailer, the vehicle parameters comprise parameters related to steering control of the semi-trailer, and the historical state information is steering control parameters recorded by the semi-trailer at different historical moments;

the model building module is used for building a vehicle kinematic model based on the vehicle parameters and determining a relation among the front wheel corner of the tractor, the equivalent front wheel corner of the trailer and the hinge angle based on the vehicle kinematic model;

the amplitude limiting processing module is used for carrying out amplitude limiting processing on the current equivalent front wheel steering angle of the trailer according to the equivalent front wheel steering angle of the first trailer and the compensation hinging angle to obtain an equivalent front wheel steering angle of the second trailer;

and the steering control module is used for substituting the equivalent front wheel steering angle and the compensation hinging angle of the second trailer into the relation to obtain steering angle control quantity, and carrying out steering control on the semitrailer based on the steering angle control quantity.

9. A vehicle, the vehicle comprising a controller, the controller comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory having stored therein computer instructions, the processor executing the computer instructions to perform the method of controlling steering of a semitrailer vehicle as claimed in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that the computer-readable storage medium has stored thereon computer instructions for causing a computer to execute the semitrailer vehicle steering control method according to any one of claims 1 to 7.