CN115610416A

CN115610416A - Control method for queue running vehicles

Info

Publication number: CN115610416A
Application number: CN202211644480.6A
Authority: CN
Inventors: 刘滨
Original assignee: Suzhou Cubic Yuan Intelligent Technology Co ltd
Current assignee: Suzhou Cubic Yuan Intelligent Technology Co ltd
Priority date: 2022-12-21
Filing date: 2022-12-21
Publication date: 2023-01-17
Anticipated expiration: 2042-12-21
Also published as: CN115610416B

Abstract

The invention relates to a control method of a queue running vehicle, which comprises a steering control method and a cooperative driving and braking control method; during steering control, coordinate values of a group of track points passed by the pilot vehicle are respectively obtained based on the coordinate system of each following vehicle; based on the vehicle kinematics principle and real-time wheel rotation angles and motion parameters, synchronous coordinate transformation is carried out on the track points, the ideal driving track of each following vehicle is fitted, and steering of each following vehicle is controlled according to the track; meanwhile, synchronous and feedback driving braking control is timely executed based on the driving braking intensity difference between each following vehicle and each pilot vehicle and the distance between the front vehicle and the rear vehicle; the invention can realize the safe and stable automatic in-line running of a plurality of vehicles on the same track, thereby reducing the labor cost and the energy cost in the use process of the vehicles.

Description

Control method for queue running vehicles

Technical Field

The invention relates to the technical field of vehicle engineering, in particular to a control method for vehicles running in a queue.

Background

The steering control and the cooperative control of the vehicles are important key technologies for vehicles running in a queue, the former ensures that the vehicles run along the same track, and the latter ensures that the front and rear vehicles move cooperatively, so that the workshop distance is kept stable, and rear-end collision is prevented. However, in the prior art, the same-track following control method usually collects the geographic coordinate information of the vehicle based on a geodetic coordinate system and fits the vehicle running track according to the geographic coordinate information. However, the collection of accurate geographic coordinates of the vehicle is extremely difficult, and the requirements of vehicle positioning accuracy and stability and reliability are difficult to meet by means of satellite positioning, optical positioning and the like; in addition, in the prior art, the driving and braking control of the vehicle is usually based on the front-rear vehicle distance for feedback control, but the method has a certain time delay, and the vehicle is easy to rear-end in an emergency. Based on the above, the invention provides a control method for queue running vehicles, which is used for solving the problems in the prior art, and a technical scheme which is the same as or similar to the technical scheme of the invention is not found through retrieval.

Disclosure of Invention

The invention aims at: the method is used for realizing automatic in-line running of a plurality of vehicles on the same track, and ensuring the motion coordination of all vehicles and the stable inter-vehicle distance.

The technical scheme of the invention is as follows: a control method for a queue running vehicle comprises a vehicle steering control method, and specifically comprises the following steps:

among the vehicles running in the queue, the vehicle running at the head is called a pilot vehicle, and the central point of the front axle of the pilot vehicle is marked as F ₁ (ii) a Setting Q as a natural number more than or equal to 2, calling the Q-th vehicle in the driving queue as a following vehicle Q, and recording the Q-th vehicle as a vehicle Q, and recording the central point of the front axle of the following vehicle Q as F _Q (ii) a The steering control method of the vehicle Q comprises the following specific steps:

(1) Defining a coordinate system and a time series, setting F _Q As the origin of coordinates, in the horizontal projection plane, the side along the vehicle body direction and facing the vehicle head is the positive direction of the Y axis, the side perpendicular to the vehicle body direction and facing the right side of the vehicle body is the positive direction of the X axis, and a coordinate system Z is established _Q (ii) a Defining any moment as a k moment, and changing the k moment into a k +1 moment after a time delta t;

(2) Initialization, k =0;

(3) After a certain time Δ t, the time is changed from the time k to the time k +1, that is, k = k +1;

(4) Solving the coordinate system Z at the current time k _Q Lower, central point F of front axle of piloting vehicle ₁ Coordinate value F of _1k （x _1k ，y _1k ) Record F _1k Is a track point;

(5) Estimating the coordinate system Z from the time k-1 to the time k _Q Wherein the turning angle of the vehicle Q from the time k-1 to the time k is solved,i.e. the coordinate system Z _Q Is theta _Qk Defining the rotation angle to be positive in anticlockwise rotation and negative in clockwise rotation; theta _Qk =Δt*ω _Qk ，ω _Qk The rotation speed of the vehicle body is measured by a gyroscope arranged on the vehicle; speedometer mounted on the vehicle acquires F _Q Velocity v at time k _Qk (ii) a At the time of k-1, the recorded steering angle of the front axle is C _Qk-1 (ii) a According to the principle of vehicle plane motion, the change parameters of the coordinate origin can be solved, wherein:

x-axis variation a = -delta t v _Qk *sin(C _Qk-1 +θ _Qk /2)；

Y-axis variation b = Δ t × ν _Qk *cos(C _Qk-1 +θ _Qk /2)；

Recording the speed value v of the current k moment _Qk The method is used for calculating the driving mileage of the pilot vehicle between the track points in the next step;

(6) Coordinate transformation is carried out, and n track points F between the front axle of the pilot vehicle and the front axle of the vehicle Q under a k-1 moment coordinate system _1k-1 ，F _1k-2 ，…，F _1k-n The coordinate values are sequentially converted into coordinate values under a current k moment coordinate system; according to the coordinate transformation equation, the transformed coordinate values of the X axis and the Y axis are respectively:

X _1k-m =（x _1k-m -a）*cosθ _QK +（y _1k-m -b）*sinθ _QK ，

Y _1k-m =（y _1k-m -b）*cosθ _QK -（x _1k-m -a）*sinθ _QK ；

wherein the coordinate value x on the left side of the equation _1k-m And y _1k-m As a lower trace point F of the time-k coordinate system _1k-m Coordinate value of (2), coordinate value of equation right side x _1k-m And y _1k-m Is a trace point F under a k-1 moment coordinate system _1k-m The coordinate values of (a); m is 1,2, \ 8230 \ n;

the method for evaluating the number n of the track points needing coordinate transformation comprises the steps of estimating the secondary track points F of the pilot vehicle on the assumption that the speeds of the pilot vehicle and the vehicle Q are approximately equal _1k-m To F _1k Distance traveled S _Qm ；

S _Qm =(ν _Qk-1 +ν _Qk-2 +…+ν _Qk-m ）*Δt；

Setting the mileage difference of two front axles relative to the same datum point as L when the pilot vehicle and the vehicle Q normally run _Q When S is _Qm >L _Q When the vehicle is in a driving state, the value of m is not increased, and n = m, namely, the track point which is not between the front axle of the pilot vehicle and the front axle of the vehicle Q does not influence track calculation and steering control, and coordinate transformation is not needed, so that the calculation resources are saved;

(7) One track point F obtained based on k time _1k And n track points F obtained at previous moments and with coordinate values transformed to the current k moment coordinate system _1k-1 ，F _1k-2 ，…，F _1k-n N +1 track points fitting the central point F of the front axle of the vehicle Q _Q The ideal running track of the front axle is controlled by the following car steering controller according to the running track so as to lead the center point F of the front axle _Q Driving along the track, and simultaneously recording the steering angle C of the front axle at the moment _Qk The method is used for calculating the coordinate system transformation parameters at the next moment;

(8) If the vehicle exits the queue running state, the step is finished; if the vehicle continues to run in the queue, returning to the step (3);

the vehicle steering control method of the present invention is fundamentally different from the prior art.

Firstly, one salient inventive step is that it "does not require" vehicle positioning, trajectory calculation and steering control based on a geodetic coordinate system; the method comprises the following steps of positioning a navigator in real time based on a coordinate system of each follower vehicle, and acquiring coordinate values of a group of track points passed by the navigator; based on the vehicle kinematics principle, carrying out real-time coordinate transformation on the track points according to parameters such as the wheel rotation angle, the vehicle body rotation speed, the vehicle speed and the like of the vehicle; and fitting the ideal running track of each following vehicle according to the ideal running track. Unlike in the geodetic coordinate system, the track is static, in the invention, the ideal track is dynamically changed in value along with the change of the vehicle coordinate system, because the coordinate system is fixed with the following vehicle, the real-time deviation of the vehicle and the ideal track can be obviously solved, and the vehicle steering is controlled accordingly, so that the track deviation with the pilot vehicle can be effectively controlled and reduced.

In the prior art, a geodetic coordinate system is generally adopted during vehicle positioning and track calculation, and technologies and modules such as satellite positioning, optical positioning and the like are applied to position and calculate the static track of the vehicle based on the geodetic absolute coordinate system. As is well known, the satellite positioning error is large, the optical positioning stability is poor, the time delay is long, the satellite positioning system is often used in cooperation with a high-precision map and a foundation positioning target, the adaptability is weak, the cost is high, and the facility investment is huge; in particular engineering practice, a malignant traffic accident due to the adoption of the related art sometimes occurs. The track point positioning device, the gyroscope, the speedometer and the like applied by the invention are mature technical products, and have the advantages of low cost, stable performance and strong anti-interference capability, and in popular terms, no method for actively interfering the gyroscope exists at present, not to mention the influence of environmental road condition factors; therefore, compared with the prior art, the method has the advantages of low cost, high precision, strong reliability and strong adaptability.

Secondly, in the step (5), the calculation process of the coordinate transformation parameters of the track points is not based on the conventional similar technology, particularly a broken line motion rule commonly used in an inertial navigation track integral calculation technology, but adopts a vehicle kinematics principle which is more in line with the vehicle motion characteristics; the broken line motion is characterized in that the track line is simplified into a broken line consisting of track line segments, and the turning of the moving object is simplified into turning at the intersection of the track line segments; however, in the actual movement process of the vehicle, including the central point of each front axle of the following vehicle, each point on the vehicle moves along an arc line around the instantaneous center of the vehicle, and the movement is not simplified into a broken line formed by straight line segments. Based on the principle, the coordinate transformation parameters, particularly the displacement parameters of the coordinate origin at each moment, can be accurately calculated by combining parameters such as vehicle speed, vehicle body rotating speed, wheel rotating angle and the like, and coordinate transformation and track calculation are carried out on each track point, so that more accurate steering control is realized.

Thirdly, in the step (6), when the number n of trace points needing coordinate transformation is determined, the existing similarity technology usually takes whether the coordinate value of the Y axis of the transformed trace points is less than 0 as the transformation terminationAccording to the method, although the method is simple, under special conditions, such as when a driving queue turns around, the Y-axis coordinate value of a part of track points behind the central point of the front axle of the pilot vehicle is less than 0, if the method provided by the prior art is used, when the first track point F is finished _1k-1 After the coordinate transformation, the coordinate value of the Y axis is less than 0, and the coordinate transformation is immediately terminated, so that subsequent track points are lost, the track resolving failure is caused, and even the vehicle is out of control; in the invention, based on the driving mileage of the pilot vehicle between the track points, the mileage is compared with the normal mileage difference of the following vehicle of the pilot vehicle, and the comparison result is used as the condition for continuing to carry out coordinate transformation of the track points; therefore, the track points between the front axle of the pilot vehicle and the front axle of the vehicle Q can be subjected to coordinate transformation when the wheelless driving queue is driven linearly, turns or turns around, subsequent track resolving and steering control cannot be influenced, and the stability and robustness of control are further improved.

In addition, in the prior art, historical corner information of the pilot vehicle is recorded, and corresponding wheel corner control is performed on the following vehicle based on the mileage difference. As will be understood by those skilled in the art, the technology has no error feedback and correction function, and can generate error accumulation along with the running mileage. For example, if the following vehicle has a track deviation, the following vehicle should not be steered according to the historical turning angle of the pilot vehicle at the close position, otherwise the following vehicle may move to a position further away from the ideal track.

Preferably, in the steering control method of the vehicle Q, in the step (4), the track point F is calculated _1k Coordinate value F of _1k （x _1k ，y _1k ) The method comprises the following steps:

the method comprises the steps that a plurality of radio frequency positioning tags are arranged on a pilot vehicle, and in a horizontal projection plane, the radio frequency positioning tags are arranged at the central point F of the front axle of the pilot vehicle ₁ As a circle center, r is on a circle with a radius, wherein r is a constant;

a radio frequency positioning base station is arranged on the vehicle Q and is based on the vehicle coordinate system Z _Q And calculating the coordinate value of each radio frequency positioning label, wherein the track point F is calculated due to the error between the coordinate calculation value of each label and the true value thereof _1k Coordinate value F of _1k （x _1k ，y _1k ) In time, data filtering is required, and specific methods comprise a least square method, a Hough circle method and the like;

fitting a circle with radius r according to the least square method based on the coordinate values of the radio frequency positioning tags, and recording the coordinate value of the center of the circle as a track point F _1k Coordinate values of (2);

according to the Hough circle method, in the obtained coordinates of the plurality of positioning labels, three coordinate points are selected randomly to determine a circle and the coordinates of the center of the circle; traversing the combination of any three coordinate points, calculating a group of circle center coordinate values in a multiplying way, and taking the group of coordinates as a track point F _1k A sample of coordinate values; according to the Hough circle method, obtaining the circle center coordinate with the highest occurrence probability and recording the circle center coordinate as a track point F _1k Coordinate values of (2); for example, 30 coordinate values can be obtained by 30 positioning tags, 4060 combination modes are provided for any three coordinate points through arrangement and combination, 4060 circle center coordinate values can be obtained as statistical samples, and the coordinate value with the highest occurrence probability can be obtained according to the hough circle method and recorded as the track point F _1k Coordinate values of (2); obviously, based on the probability statistical principle, the more the circle center coordinate values are counted, the more the track point F is obtained by resolving _1k The closer the coordinate value is to the true value, i.e. the trace point F _1k The smaller the resolving error of (2) is; the method can obtain a large number of track point coordinate sample values based on a small number of radio frequency positioning tags, so that the resolving precision of track points can be improved; in addition, the Hoff circle method can remove abnormal coordinate values which deviate from expected values to a large extent and have small occurrence probability, and the track point F can be further improved _1k The resolving precision of (2);

the method has simple components and low cost, and can more accurately acquire the track point F by acquiring the coordinate points of a plurality of radio frequency positioning tags and the combination of the coordinate points, and through numerical calculation and data filtering _1k The coordinate values of (2).

Preferably, in the steering control method of the vehicle Q, in the step (4), the track point F is calculated _1k Coordinate value F of _1k （x _1k ，y _1k ) The other method is as follows:

determining the relative geometric position relationship between front and rear adjacent vehicles in the front Q vehicles, wherein the determination method comprises any one or combination of multiple of visual positioning, radio frequency positioning, ultrasonic positioning, laser positioning and mechanical positioning;

calculating the position in Z according to the obtained relative geometric position relation between the front and the rear adjacent vehicles and the vehicle body dimension chain _Q In the coordinate system, F ₁ Coordinate value F of _1k （x _1k ，y _1k ）。

Preferably, the method further comprises a cooperative driving and braking control method of the vehicle Q, which is as follows:

collecting and resolving control parameters: the pilot vehicle driving brake control unit acquires the travel P of the accelerator pedal of the vehicle in real time ₁ And the brake pedal stroke T ₁ The data is transmitted to a follow-up vehicle driving brake control unit in a wired or wireless mode; the follow-up vehicle driving braking control unit is used for driving the brake according to the pedal stroke data P ₁ 、T ₁ And calculating the equivalent accelerator pedal travel P of the vehicle Q by an empirical formula _Q Equivalent brake pedal stroke T _Q (ii) a The follow-up driving brake control unit acquires the actual strokes of an accelerator pedal and a brake pedal of a vehicle Q in real time to be P respectively _Q0 And T _Q0 The deviations of this actual travel from the equivalent travel are referred to as throttle deviation e and brake deviation f, respectively, wherein,

e=|P _Q0 -P _Q |；

f=|T _Q0 -T _Q |；

the limit values of the travel deviations e and f are set to e ₁ 、f ₁ And e is a ₁ >0，f ₁ >0；

The vehicle distance sensor arranged on the vehicle Q measures the distance between the vehicle and the vehicle in front to be d, and the ideal vehicle distance is set to be d ₀ Distance between vehicles limit value d ₁ 、d ₂ And 0 is<d ₁ <d ₀ <d ₂ ；

For calculating equivalent accelerator pedal travel P of vehicle Q relative to pilot vehicle _Q And equivalent brake pedal travel T _Q The empirical formula of (2) can be obtained through experiments, and the specific method is as follows:

separately driven piloting vehicleWhen the vehicle Q runs at a certain same speed, the travel of the accelerator pedal of the pilot vehicle is recorded as P ₁ The travel of the Q accelerator pedal of the vehicle is P _Q Balance P _Q Is P ₁ Equivalent accelerator pedal travel of (a); recording a plurality of groups of throttle strokes P under different vehicle speeds ₁ And P _Q Empirical formula P capable of fitting equivalent accelerator pedal travel of vehicle Q relative to pilot vehicle _Q =f(P ₁ )；

Respectively braking the pilot vehicle and the vehicle Q, and recording the travel of the brake pedals of the pilot vehicle and the vehicle Q as T when the braking acceleration is the same ₁ And T _Q Scale T _Q Is T ₁ Equivalent brake pedal travel of (a); by recording the travel T of the brake pedal under a plurality of groups of different braking accelerations ₁ And T _Q Empirical formula T capable of fitting equivalent brake pedal travel of vehicle Q relative to pilot vehicle _Q =f(T ₁ )；

The follow-up vehicle driving and braking control unit controls an accelerator and a brake pedal of the vehicle Q based on the parameters, and specifically comprises driving synchronous control, braking synchronous control, driving feedback control and braking feedback control;

driving synchronous control to control the travel of the Q-wire controlled accelerator pedal of the vehicle to an equivalent travel P _Q ；

The Q-wire control brake pedal of the vehicle is controlled to the equivalent stroke T by brake synchronous control _Q ；

Driving feedback control when d < d ₀ When the accelerator pedal by wire of the vehicle Q is controlled to reduce the accelerator stroke, when d is larger than d ₀ When the throttle is in the closed state, the throttle stroke is increased; the specific adjustment control method can adopt a PID method, a sliding mode control method and the like;

brake feedback control when d > d ₀ When the brake-by-wire pedal of the vehicle Q is controlled to reduce the brake stroke, when d is less than d ₀ When the brake is started, the brake stroke is increased; the specific adjusting control method can adopt a PID method, a sliding mode control method and the like;

the specific control execution method comprises the following steps:

when e is>=e ₁ And d is d ₁ <=d<=d ₂ When the driver is started, driving synchronization control is executed;

when f is>=f ₁ And d is ₁ <=d<=d ₂ Executing brake synchronization control;

when 0 is present<=e<e ₁ And d is ₁ <=d<=d ₂ And P is _Q0 >At 0; or when d>d ₂ When the current is over; performing drive feedback control;

when 0 is present<=f<f ₁ And d is ₁ <=d<=d ₂ And T is _Q0 >At 0; or when 0<=d<d ₁ When the current is over; executing brake feedback control;

when P is present _Q0 =T _Q0 =0, and d>=d ₀ When the driving is stopped, the driving feedback control is executed; when P is present _Q0 =T _Q0 =0, and d<d ₀ At this time, the brake feedback control is executed.

The invention relates to a control method of vehicles running in a queue, which abandons a geodetic coordinate system commonly adopted in the prior art, creatively provides a positioning and steering control technology based on a coordinate system of a vehicle, does not need any form of vehicle-road cooperative facilities, and can realize automatic in-line running of a plurality of vehicles on a common road along the same track by real-time coordinate transformation and track calculation of track points according to vehicle motion parameters and motion principles; meanwhile, the cooperative driving and braking performance of the vehicles running in the queue is optimized. The vehicle queue can greatly reduce the number of drivers, reduce air resistance and reduce labor cost and energy cost for vehicle use.

Drawings

The invention is further described below with reference to the following figures and examples:

fig. 1 is a flowchart of a steering control method for a vehicle Q in a control method for a vehicle in a platoon driving according to the present invention;

FIG. 2 is a schematic diagram of calculating a coordinate system variation parameter according to the present invention;

FIG. 3 is a schematic diagram of calculating coordinate system transformation parameters in the prior art;

FIG. 4 is a schematic diagram of a track point selection method during coordinate transformation of the track points according to the present invention;

FIG. 5 is a schematic diagram of the following vehicle ideal driving track fitting principle;

FIG. 6 is a schematic diagram of a control execution method in the vehicle cooperative driving and braking control method according to the present invention.

Detailed Description

The invention aims to realize the automatic queue running of a plurality of vehicles on the same track, and simultaneously ensure the motion coordination and the stable inter-vehicle distance of the front vehicle and the rear vehicle. The main control method of the queue running vehicle in the prior art comprises the following steps:

1) In order to control the front and rear vehicles to run in the same track, absolute coordinates of a pilot vehicle in a geodetic coordinate system are obtained by adopting satellite positioning, inertial positioning, optical positioning, vehicle road cooperative positioning and other modes, the track of the pilot vehicle is solved according to the absolute coordinates, a following vehicle is positioned at the same time, and the following vehicle and the pilot vehicle are controlled to run in the same track; the method has the advantages that the satellite positioning accuracy is low and unstable, and the influence of the weather environment shielding is large; the inertial positioning has error accumulation; the optical positioning has the problems of poor environmental stability, high computational power resource requirement, long time delay, normal use by matching with a high-precision map and the like; the problems of large investment, limited vehicle running area, poor flexibility and the like exist in the cooperative positioning of the vehicle and the road. In addition, the trainees also provide a method for steering control of the following vehicle based on the historical turning angle of the pilot vehicle and the mileage difference between the front vehicle and the rear vehicle; the method obviously has the problem that the error is not correctable.

2) The method has the advantages that the driving and the braking are coordinated, the feedback control is usually carried out on the braking driving of a following vehicle based on the distance between a front vehicle and a rear vehicle in the prior art, but the reaction delay is large under the conditions of emergency acceleration, emergency braking and the like of a pilot vehicle, and the safety risk is easy to generate;

in order to solve the problems, the invention creatively provides a new technical scheme.

The present invention will be further described in detail with reference to the following specific examples:

the control method of train running vehicles includes that the vehicle running at the head of the train running vehicles is called a pilot vehicle, and the central point of the front axle of the pilot vehicle is marked as F ₁ (ii) a Setting Q as a natural number more than or equal to 2, calling the Q-th vehicle in the driving queue as a following vehicle Q, and recording the Q-th vehicle as a vehicle Q, and recording the central point of the front axle of the following vehicle as F _Q (ii) a When the vehicle queue runs, the pilot vehicle can be a personThe driven vehicle may be an unmanned vehicle.

As shown in fig. 1, the steering control method of the vehicle Q is specifically as follows:

(1) Defining a coordinate system and a time series, setting F _Q As the origin of coordinates, in the horizontal projection plane, the side along the vehicle body direction and facing the vehicle head is the positive direction of the Y axis, the side perpendicular to the vehicle body direction and facing the right side of the vehicle body is the positive direction of the X axis, and a coordinate system Z is established _Q (ii) a Defining any moment as a moment k, and changing the moment k +1 after a time delta t;

(2) Initialization, k =0;

(3) After the time Δ t, the time is changed from the time k to the time k +1, that is, k = k +1;

(4) Solving for time k in coordinate system Z _Q Lower, central point F of front axle of pilot vehicle ₁ Coordinate value F of _1k （x _1k ，y _1k ) Simultaneously recording the coordinate point as a track point F _1k (ii) a The method specifically comprises two methods:

the first method is as follows:

a plurality of radio frequency positioning tags are arranged on a pilot vehicle, and in a horizontal projection plane, all the radio frequency positioning tags are arranged at the central point F of the front axle of the pilot vehicle ₁ As a circle center, r is on the circumference of the radius, wherein r is a constant;

arranging a radio frequency positioning base station on the vehicle Q based on the vehicle coordinate system Z _Q And resolving coordinate values of the radio frequency positioning tags, wherein the error exists between the coordinate calculation value of each tag and the true value of the coordinate calculation value, and the trace point F is resolved _1k Coordinate value F of _1k （x _1k ，y _1k ) In time, data filtering is required, and specific methods comprise a least square method, a Hough circle method and the like;

fitting a circle with radius r according to the least square method based on the coordinate values of the radio frequency positioning tags, and recording the coordinate value of the center of the circle as a track point F _1k The coordinate values of (a);

the Hough circle method is characterized in that in the obtained coordinates of a plurality of positioning labels, three coordinate points are selected randomly to determine a circle and the coordinates of the center of the circle; traversing the combination of any three coordinate points, a group of circles can be solved in multiplesThe coordinate value of the center is used as a track point F _1k A sample of coordinate values; according to the Hough circle method, obtaining the circle center coordinate with the highest occurrence probability and recording the circle center coordinate as a track point F _1k Coordinate values of (2); for example, 30 coordinate values can be obtained by 30 positioning tags, 4060 combination modes are provided for any three coordinate points through arrangement and combination, 4060 circle center coordinate values can be obtained as statistical samples, and the coordinate value with the highest occurrence probability can be obtained according to the hough circle method and recorded as the track point F _1k Coordinate values of (2); obviously, based on the probability statistical principle, the more the circle center coordinate values are counted, the more the track point F is obtained by calculation _1k The closer the coordinate value is to the true value, i.e. the trace point F _1k The smaller the resolving error is; according to the method, a large number of coordinate sample values of the track points can be obtained based on a small number of radio frequency positioning tags, so that the resolving precision of the track points can be improved; in addition, the Hough circle method can remove abnormal coordinate values which deviate from expected values to a large extent and have small occurrence probability, and the track point F can be further improved _1k The resolving precision of (2);

The second method is as follows:

(5) Estimate the coordinate system Z from the time k-1 to the time k _Q Wherein the angle of rotation of the vehicle Q from the time k-1 to the time k, i.e. the coordinate system Z, is solved _Q Is theta _Qk ，θ _Qk =Δt*ω _Qk ，ω _Qk For the speed of rotation of the vehicle body, the value of which is measured by a gyroscope mounted on the vehicleAnd at the last moment (k-1 moment), the following vehicle steering controller records the rotating angle of the front wheel Q of the vehicle as C _QK-1 Defining the rotation angle to be positive in anticlockwise rotation and negative in clockwise rotation; the speed sensor arranged on the front axle of the vehicle Q can measure the speed of the left and right two wheels, and the average value is taken to obtain the central point F of the axle _Q Velocity v at time k _Qk (ii) a If the shaft is a driving shaft, the rotating speed of a power mechanism (such as the rotating speed of a motor or an engine) can be measured through a speed sensor, and the central point F of the shaft can be calculated by combining the transmission ratio and the wheel diameter _Q Speed v _Qk ；

Referring to FIG. 2, the origin of coordinates F is from time k-1 to time k based on the principle of planar motion of the vehicle _Q Along the arc line W by F _Qk-1 Move to F _Qk ，F _Q The velocities of the front point and the rear point are respectively v _Qk-1 V and v _Qk The two speed directions are tangent to the arc line W, and the included angle between the two speed directions and the Y axis is the wheel rotation angle C _Qk-1 And C _Qk (ii) a During a short movement time Δ t, the wheel angle C can be assumed _Qk-1 And C _Qk Approximately equal, velocity v _Qk-1 And v _Qk Approximately equal, and the included angle between the two speeds is equal to the rotation angle theta of the coordinate system _Qk The length of the arc line W and the line segment F _Qk-1 F _Qk Approximately equal, having a length value Δ t v _Qk (ii) a Can prove the line segment F _Qk-1 F _Qk V and speed v _Qk-1 The included angle should be theta _Qk 2; based on the above geometric relationship, the coordinate origin F can be calculated _Q Wherein:

x-axis variation a = -delta t v _Qk *sin(C _Qk-1 +θ _Qk /2)；

Y-axis variation b = Δ t × ν _Qk *cos(C _Qk-1 +θ _Qk /2)；

Simultaneously recording the speed value v of the current k moment _Qk The method is used for calculating the driving mileage of the track point pilot vehicle in the next step;

different from the prior art, the resolving process of the coordinate system transformation parameters in the step is based on the vehicle kinematics principle, and is not the broken line motion law commonly adopted in the prior art. As shown in FIG. 3, the motion of the fold line is characterized by moving objectsThe motion track is simplified into a broken line consisting of track line segments, and the motion track is simplified into a straight line segment F in a short time delta t _Qk-1 F _Qk (ii) a When the object moves, steering is carried out at the intersection point of the track line segments, and the steering angle is equal to the turning angle theta of the coordinate system _Qk . Referring back to fig. 2, based on the kinematics principle of the vehicle, in the moving process of the vehicle, the whole vehicle rotates based on the instantaneous center of speed, and during the linear motion, the whole vehicle can be regarded as infinite rotating radius, and each point on the vehicle comprises a front axle central point F _Q (origin of coordinates), the motion trails of which are all circular arc lines taking the instantaneous center of speed as the center of a circle; in a short time delta t, the motion track of the vehicle is a circular arc line and is not simplified into a straight line segment, and the steering process is continuously completed in the motion process and is not completed suddenly at a turning point; thus, the origin of coordinates F _Q The motion of the coordinate system is simplified into the broken line motion, and the calculation of the coordinate system transformation parameters is carried out based on the broken line motion rule, and the result is not accurate. The invention is based on the vehicle kinematics principle and more conforms to the origin of coordinates F _Q The calculation process of the coordinate system transformation parameters is more reasonable, and the result is more accurate.

(6) Coordinate transformation, namely transforming n track points F between the front axle of the pilot vehicle and the front axle of the vehicle Q in a k-1 moment coordinate system _1k-1 ，F _1k-2 ，…，F _1k-n The coordinate values are sequentially converted into coordinate values under a current k moment coordinate system; according to the coordinate transformation equation, the transformed coordinate values of the X axis and the Y axis are respectively as follows:

X _1k-m =（x _1k-m -a）*cosθ _QK +（y _1k-m -b）*sinθ _QK ，

Y _1k-m =（y _1k-m -b）*cosθ _QK -（x _1k-m -a）*sinθ _QK ；

need to perform coordinatesThe number n of transformed track points is evaluated by estimating the secondary track points F of the pilot vehicle on the assumption that the speeds of the pilot vehicle and the vehicle Q are approximately equal _1k-m To F _1k Distance traveled S _Qm ；

S _Qm =(ν _Qk-1 +ν _Qk-2 +…+ν _Qk-m ）*Δt；

in this step, points of track F _1k-n The initial coordinate values of the three-dimensional coordinate system are solved at the k-n moment, and the coordinate values of the three-dimensional coordinate system are subjected to n times of coordinate transformation to the k moment, so that a certain degree of error accumulation can be generated, but the total transformation times are limited, so that the accumulation of the total error is also limited; in the existing inertial navigation technology, a geodetic coordinate system is generally adopted for track calculation, and uncontrollable track error accumulation can be generated along with the increase of the running time and mileage of a vehicle; under the normal condition, the vehicle gauge class inertia module with higher precision can generate a track error of more than 10 meters after running for 10 kilometers, the error level is completely unacceptable when a vehicle queue runs, and the error of 10 meters means the deviation of 3 lanes, so that unexpected disastrous risks can be caused to vehicles in other lanes in a road; when the vehicle is driven in a queue, a track resolving error of about 10 centimeters is usually allowed; when the method is adopted, the track error is generally positively correlated with the length of a fleet running in a queue, for example, the length of the fleet of 30 meters is taken as an example, the track resolving error can be controlled within 3-5 centimeters under the same sensor precision, and the accumulation of running time and mileage can be avoided;

in addition, when the number n of track points needing coordinate transformation is determined, the existing similarity technology usually takes whether the Y-axis coordinate value of the transformed track points is less than 0 as the condition of transformation termination, and the method is simple but has defects; as shown in FIG. 4, when the train turns around, j track points F behind the front axle of the pilot _1k-1 ，F _1k-2 ，…，F _1k-j The coordinate values of the Y axis are all less than 0, and when the coordinate transformation is carried out on the track points by the method, the first track point F is _1k-1 After coordinate transformation, the Y-axis coordinate value is smaller than 0, so that the coordinate transformation is terminated in advance, the coordinate value of a subsequent track point cannot be obtained continuously, and track calculation failure and even vehicle runaway are caused; in the invention, the method for determining the number n of the track points needing coordinate transformation is based on the track points F of the pilot vehicle which are subjected to coordinate transformation _1k-m To its current position F _1k Actual mileage of S _Qm And the mileage S _Qm Whether or not it is greater than the mileage difference L _Q As the basis for stopping coordinate transformation; therefore, no matter the driving queue runs straight, turns or turns around, the track point F between the front axle of the pilot vehicle and the front axle of the vehicle Q can be measured _1k-1 ，F _1k-2 ，…，F _1k-n Coordinate transformation is carried out, subsequent track calculation and steering control are not influenced, and the stability and robustness of vehicle steering control are further improved;

(7) One track point F obtained based on k time _1k And n track points F obtained at previous moments and with coordinate values transformed to the current k moment coordinate system _1k-1 ，F _1k-2 ，…，F _1k-n N +1 track points fitting the central point F of the front axle of the vehicle Q _Q According to an ideal driving track of F _Q The deviation of the coordinates (0, 0) of the vehicle front axle and the track is controlled by a following vehicle steering controller to steer a steer-by-wire mechanism arranged on the vehicle front axle so as to lead the center point F of the vehicle front axle _Q Running along the track, and recording the steering angle C of the front wheel at the moment _Qk Preparing coordinate system transformation parameter calculation for the next moment;

referring to fig. 5, Q =3 is taken as an example, based on the vehicle 3 coordinate system Z ₃ With origin of coordinates F ₃ (ii) a At the moment k, the central point F of the front axle of the pilot vehicle can be obtained ₁ Passing set of coordinate points F _1k And F _1k-1 ，F _1k-2 ，…，F _1k-n And fitting F according to the coordinate values ₃ Ideal travel locus R of ₃ Tracing point F in the figure _1k-n After the front axle of the vehicle is arranged, the subsequent track points do not influence the steering control of the vehicle, and coordinate transformation is not needed, so that the computing resource is saved; after the track calculation at the moment is finished, the center point of the front axle of the vehicle Q, namely the coordinate origin F is determined ₃ (0, 0) deviation from the ideal running track, the following vehicle steering controller controls a steer-by-wire mechanism mounted on the vehicle to steer so that the center point F of the front axle of the vehicle ₃ Along the ideal trajectory R ₃ Driving, and recording the steering angle C of the front wheel at the same time _Qk The method is used for calculating the coordinate transformation parameter of the next moment; when the next time (the time k + 1) is reached, under the coordinate system of the time k +1, a new track point F can be obtained according to the step (4) firstly _1k+1 The coordinates of the vehicle 3 are moving, so that the coordinate system of the vehicle is also moving, and the n +1 track points need to be subjected to coordinate transformation as required to obtain coordinate values of the group of track points at the time of k +1; it is obvious that the points of the track and the corresponding tracks are dynamically changing, but due to the origin of coordinates F ₃ The relative deviation from the "dynamic trajectory" is analyzable, so it does not affect the steering control of the vehicle, which is also an important principle innovation of the present invention.

(8) If the vehicle exits the queue running state, the step is ended; and (4) if the vehicle continues to run in the queue, returning to the step (3).

In the steering control method of the vehicle Q, based on the innovation of the algorithm principle, the calculation and steering control of the ideal driving track of the vehicle Q is carried out based on the coordinate system of the vehicle Q without a geodetic coordinate system or analyzing the geographical coordinate information of each vehicle, and the geographical coordinate information is provided by a foundation positioning target or a vehicle path cooperative system in any form, so that the investment of infrastructure can be greatly saved. Taking a foundation positioning magnetic nail with relatively stable reliability as an example, the road reconstruction cost per kilometer is usually measured by tens of millions; although the cost of the centimeter-level precision vehicle-road cooperative RTK positioning system is low, the positioning precision is greatly influenced by factors such as weather and terrain environment, huge potential safety hazards exist, and the requirements on precision and reliability when a vehicle queue runs cannot be met at present. In the method, the positioning and steering control does not need foundation facilities, so the method has wide road adaptability, vehicles can automatically run on a common road in a row, and the method has good flexibility and applicability.

Cooperative drive and brake control method for vehicle Q:

collecting and resolving control parameters: the pilot vehicle driving brake control unit acquires the travel P of the accelerator pedal of the vehicle in real time ₁ And the brake pedal stroke T ₁ The data is transmitted to a follow-up vehicle driving brake control unit in a wired or wireless mode; the follow-up vehicle driving braking control unit drives the brake according to the pedal travel data P ₁ 、T ₁ And calculating the equivalent accelerator pedal travel P of the vehicle Q by an empirical formula _Q Equivalent brake pedal stroke T _Q (ii) a The follow-up driving brake control unit acquires the actual strokes of an accelerator pedal and a brake pedal of a vehicle Q in real time to be P respectively _Q0 And T _Q0 The deviations of this actual travel from the equivalent travel are referred to as throttle deviation e and brake deviation f, respectively, wherein,

e=|P _Q0 -P _Q |；

f=|T _Q0 -T _Q |；

The vehicle distance sensor mounted on the vehicle Q measures the distance d between the vehicle and the vehicle in front, and the ideal vehicle distance is set to d ₀ Distance between vehicles limit value d ₁ 、d ₂ And 0 is<d ₁ <d ₀ <d ₂ ；

when the pilot vehicle and the vehicle Q are driven at the same speed respectively, the travel of an accelerator pedal of the pilot vehicle is recorded as P ₁ The travel of the Q accelerator pedal of the vehicle is P _Q Balance of P _Q Is P ₁ Equivalent accelerator pedal travel of (a); recording a plurality of groups of accelerator strokes P under different vehicle speeds ₁ And P _Q Experience formula capable of fitting equivalent accelerator pedal travel of vehicle Q relative to pilot vehicleFormula P _Q =f(P ₁ )；

Respectively braking the pilot vehicle and the vehicle Q, and recording the travel of the brake pedals of the pilot vehicle and the vehicle Q as T when the braking acceleration is the same ₁ And T _Q Balance T _Q Is T ₁ Equivalent brake pedal travel of (a); by recording the travel T of the brake pedal under a plurality of groups of different braking accelerations ₁ And T _Q Empirical formula T capable of fitting equivalent brake pedal travel of vehicle Q relative to pilot vehicle _Q =f(T ₁ )；

drive synchronous control to control the travel of the drive-by-wire accelerator pedal of the vehicle Q to the equivalent travel P _Q ；

Brake synchronous control, namely controlling the travel of a brake-by-wire pedal of the vehicle Q to an equivalent travel T _Q ；

Driving feedback control when d < d ₀ When the accelerator pedal by wire of the vehicle Q is controlled to reduce the accelerator stroke, when d is larger than d ₀ When the throttle is in the closed state, the throttle stroke is increased; the specific adjusting control method can adopt a PID method, a sliding mode control method and the like;

brake feedback control when d > d ₀ When the brake-by-wire pedal of the vehicle Q is controlled to reduce the brake stroke, when d is less than d ₀ When the brake is started, the brake stroke is increased; the specific adjustment control method can adopt a PID method, a sliding mode control method and the like;

as shown in fig. 6, the horizontal axis toward the right side represents the inter-vehicle distance d, the vertical axis toward the upper side represents the accelerator deviation e, and the vertical axis toward the lower side represents the brake deviation f; the specific control execution method comprises the following steps:

when e is>=e ₁ And d is ₁ <=d<=d ₂ In the PC area, the drive synchronous control is executed; the PC area indicates that the distance between vehicles is within the limit value d ₁ 、d ₂ Within, and an ideal value d ₀ When the driving strength of the vehicle Q is close to that of the pilot vehicle, but the driving strength of the vehicle Q is greatly different from that of the pilot vehicle, the driving synchronous control is executed to prevent the inter-vehicle distance d from exceedingA limit value is output;

when f is>=f ₁ And d is ₁ <=d<=d ₂ In the BC region in the figure, brake synchronization control is executed; the BC region means that the inter-vehicle distance is within the limit value d ₁ 、d ₂ When the braking intensity difference between the vehicle Q and the pilot vehicle is too large, the synchronous braking control is executed to prevent the vehicle distance d from exceeding the limit value;

when 0 is present<=e<e ₁ And d is ₁ <=d<=d ₂ And P is _Q0 >PF of 0, in the figure ₁ Region, or when d>d ₂ Time, PF in the figure ₂ A region that performs drive feedback control; PF (particle Filter) ₁ The zone is the spacing between vehicles at the limit value d ₁ 、d ₂ In the method, the driving strength of the vehicle Q is not greatly different from that of the pilot vehicle, and the vehicle Q is in a driving control state, and the driving feedback control is continuously kept; PF (particle Filter) ₂ The zone is that the distance between vehicles has exceeded the limit value d ₂ When the driving feedback intensity is higher, the driving feedback control is executed to reduce the inter-vehicle distance to a normal value;

when 0 is present<=f<f ₁ And d is ₁ <=d<=d ₂ And T is _Q0 >At 0, BF in the figure ₁ Region, or when 0<=d<d ₁ BF in the figure ₂ A region that performs brake feedback control; BF (BF) generator ₁ The zone is the spacing between vehicles at the limit value d ₁ 、d ₂ In addition, the braking strength difference between the vehicle Q and the pilot vehicle is not large, and the vehicle Q is in a braking state, and the braking feedback control is continuously maintained; zone BF ₂ Means that when the distance between vehicles is less than the limit value d ₁ At the moment, the brake feedback strength is higher, and the brake feedback control is executed, so that the distance between the vehicles can be effectively increased to a normal value;

when P is present _Q0 =T _Q0 =0, and d>=d ₀ When the driving is stopped, the driving feedback control is executed; when P is present _Q0 =T _Q0 =0, and d<d ₀ When the brake is started, the brake feedback control is executed; when the vehicle is in a stopped or coasting state, driving or braking control should be performed according to the inter-vehicle distance.

Unlike the method of feedback-controlling the braking driving of the vehicle Q simply by the inter-vehicle distance d, the method has advantages in that,when the pilot vehicle starts quickly, accelerates suddenly and decelerates suddenly, the motion synchronization, the motion coordination and the stable vehicle-to-vehicle distance among the vehicles can be effectively kept. For example, when a pilot vehicle runs normally and suddenly encounters emergency braking, if the vehicle Q performs driving braking feedback control on the vehicle only by means of the inter-vehicle distance d, since the feedback process needs a certain time to reach an expected state, the acceleration and speed change of the vehicle Q lags behind the acceleration and speed change of the pilot vehicle to a large extent, so that the front and rear vehicle distances are suddenly reduced, and even rear-end collision occurs; affecting the stability, safety and cooperativity of the driving queue. The driving and braking control method provided by the invention can acquire the driving and braking information of the pilot vehicle in real time, and when the travel T of the brake pedal of the pilot vehicle is reached ₁ When the acceleration is increased rapidly, the following vehicle driving and braking control unit can solve the T corresponding to the vehicle Q in real time ₁ Equivalent brake pedal stroke T _Q When T is _Q Actual brake pedal travel T with vehicle Q _Q0 The phase difference exceeds a set value f ₁ Meanwhile, the travel of the brake pedal of the vehicle Q is synchronously adjusted to T _Q Thereby effectively ensuring the acceleration and speed synchronization of the front and the rear vehicles and the stable inter-vehicle distance; when the vehicle queue normally runs, the actual accelerator pedal travel P of the vehicle Q _Q0 Normally greater than zero, actual brake pedal travel T _Q0 Should be equal to 0; at the moment, if the pilot vehicle encounters an emergency, the vehicle operation is suddenly switched from the normal accelerator stroke to the brake stroke, and the brake pedal stroke T is ₁ Generally larger, to obtain a sufficient braking effect; at this time, if the brake driving of the vehicle Q is feedback-controlled only by the inter-vehicle distance d, the accelerator stroke of the vehicle Q is first reduced by the reduction of the inter-vehicle distance, and when the inter-vehicle distance is smaller than the limit value d ₁ When the vehicle is in a rear-end collision state, the vehicle is switched to brake feedback control and the brake stroke is gradually increased, the whole process needs longer feedback time, and the rear-end collision of the front vehicle and the rear vehicle is very easy to cause due to control delay in the state; the method introduces the synchronous control of driving and braking on the basis of feedback control, and can effectively control the occurrence of dangerous conditions. After that, the real-time distance d between the vehicle Q and the front vehicle is used for carrying out feedback control and adjustment on the travel of the accelerator or the brake pedal, so that the motion synchronization and the motion coordination between the vehicles can be further ensuredMeanwhile, the vehicle distance is kept stable.

In conclusion, the queue running vehicle control method abandons a geodetic coordinate system which is usually adopted in the prior art, does not need any physical track, electronic virtual track and vehicle road cooperative facility, creatively provides a novel positioning and steering control technology, accurately calculates the running track in real time and performs steering control based on the vehicle moving coordinate system and the accurate calculation of coordinate transformation parameters, and can realize automatic in-line running of a plurality of vehicles on the same track on a common road; the invention simultaneously optimizes the motion coordination performance between vehicles, combines the synchronous control of driving and braking with the feedback control, further improves the motion coordination consistency between vehicles, more effectively ensures the stable distance between vehicles, and avoids the occurrence of dangerous situations such as rear-end collision of vehicles. The automatic train running of the vehicle can greatly reduce the number of drivers, reduce air resistance, reduce labor cost and energy cost of vehicle use, and can improve the running mileage when being applied to new energy vehicles.

Claims

1. A control method for a vehicle running in a queue is characterized by comprising a steering control method for a vehicle Q, and comprises the following specific steps:

among the vehicles running in the queue, the vehicle running at the head is called a pilot vehicle, and the central point of the front axle of the pilot vehicle is marked as F ₁ (ii) a Setting Q as a natural number more than or equal to 2, calling the Q-th vehicle in the driving queue as a following vehicle Q, and recording the Q-th vehicle as a vehicle Q, and recording the central point of the front axle of the following vehicle as F _Q (ii) a The steering control method of the vehicle Q comprises the following specific steps:

(2) Initialization, k =0;

(5) Estimate the coordinate system Z from the time k-1 to the time k _Q Wherein the angle of rotation of the vehicle Q from the time k-1 to the time k, i.e. the coordinate system Z, is solved _Q Is theta _Qk Defining that the anticlockwise rotation of the rotation angle is positive and the clockwise rotation is negative; theta _Qk =Δt*ω _Qk ，ω _Qk The rotation speed of the vehicle body is measured by a gyroscope arranged on the vehicle; speedometer mounted on the vehicle acquires F _Q Velocity v at time k _Qk (ii) a At the time of k-1, the recorded steering angle of the front axle is C _Qk-1 (ii) a According to the principle of vehicle plane motion, the change parameters of the coordinate origin can be solved, wherein:

x-axis variation a = -delta t v _Qk *sin(C _Qk-1 +θ _Qk /2)；

Y-axis variation b = Δ t × ν _Qk *cos(C _Qk-1 +θ _Qk /2)；

Simultaneously recording the current k moment velocity value v _Qk The method is used for calculating the driving mileage of the pilot vehicle between the track points in the next step;

X _1k-m =（x _1k-m -a）*cosθ _QK +（y _1k-m -b）*sinθ _QK ，

Y _1k-m =（y _1k-m -b）*cosθ _QK -（x _1k-m -a）*sinθ _QK ；

wherein the coordinate value x on the left side of the equation _1k-m And y _1k-m As a lower trace point F of the time-k coordinate system _1k-m Coordinate value of (2), coordinate value of equation right side x _1k-m And y _1k-m As a time coordinate of k-1Lower trace point F _1k-m The coordinate values of (a); m is 1,2, \ 8230 \ n;

the method for evaluating the number n of the track points needing coordinate transformation comprises the steps of estimating the secondary track points F of the pilot vehicle on the assumption that the speeds of the pilot vehicle and the vehicle Q are approximately equal _1k-m To F _1k Mileage S _Qm ；

S _Qm =(ν _Qk-1 +ν _Qk-2 +…+ν _Qk-m ）*Δt；

Setting the mileage difference of the front axle of the two vehicles relative to the same datum point as L when the pilot vehicle and the vehicle Q normally run _Q When S is _Qm >L _Q When the vehicle is in a driving state, the value of m is not increased, and n = m, namely, the track point which is not between the front axle of the pilot vehicle and the front axle of the vehicle Q does not influence track calculation and steering control, and coordinate transformation is not needed, so that the calculation resources are saved;

(7) One track point F obtained based on k time _1k And n track points F obtained at previous moments and with coordinate values transformed to the current k moment coordinate system _1k-1 ，F _1k-2 ，…，F _1k-n N +1 track points fitting the central point F of the front axle of the vehicle Q _Q The following vehicle steering controller controls the steering of the front axle of the vehicle according to the ideal driving track, so that the center point F of the front axle of the vehicle _Q Driving along the track, and simultaneously recording the steering angle C of the front axle at the moment _Qk The method is used for calculating the coordinate system transformation parameters at the next moment;

(8) If the vehicle exits the queue running state, the step is finished; and (4) if the vehicle continues to run in the queue, returning to the step (3).

2. The in-line vehicle control method according to claim 1, characterized in that: the steering control method of the vehicle Q comprises the step (4) of calculating a track point F _1k Coordinate value F of _1k （x _1k ，y _1k ) The method comprises the following steps:

fitting a circle with radius r according to the least square method based on the obtained coordinate values of the radio frequency positioning tags, and recording the coordinate value of the center of the circle as a track point F _1k Coordinate values of (2);

according to the Hough circle method, in the obtained coordinates of the plurality of positioning labels, three coordinate points are selected randomly to determine a circle and the coordinates of the center of the circle; traversing the combination of any three coordinate points, multiplying a group of circle center coordinate values, and taking the group of coordinates as a track point F _1k A sample of coordinate values; according to the Hough circle method, obtaining the circle center coordinate with the highest occurrence probability and recording the circle center coordinate as a track point F _1k The coordinate values of (2).

3. The in-line vehicle control method according to claim 1, characterized in that: the steering control method of the vehicle Q comprises the step (4) of calculating a track point F _1k Coordinate value F of _1k （x _1k ，y _1k ) The other method is as follows:

determining the relative geometric position relation between front and rear adjacent vehicles in the front Q vehicles, wherein the determination method comprises any one or combination of visual positioning, radio frequency positioning, ultrasonic positioning, laser positioning and mechanical positioning;

calculating the position Z of the vehicle body according to the acquired relative geometric position relation between the front and the rear adjacent vehicles and the vehicle body dimension chain _Q In the coordinate system, F ₁ Coordinate value F of _1k （x _1k ，y _1k ）。

4. The in-line vehicle control method according to claim 1, characterized in that: the method further comprises a cooperative driving and braking control method of the vehicle Q, which comprises the following steps:

collecting and resolving control parameters: the pilot vehicle drive brake control unit acquires the travel P of the accelerator pedal of the vehicle ₁ And the brake pedal stroke T ₁ Data is transmitted to a following vehicle driving and braking control unit in a wired or wireless mode; the follow-up driving brake control unit is based on P ₁ 、T ₁ And calculating the equivalent accelerator pedal travel P of the vehicle Q by an empirical formula _Q Equivalent brake pedal stroke T _Q Simultaneously acquiring the actual strokes of an accelerator pedal and a brake pedal of a vehicle Q to be P respectively _Q0 And T _Q0 The deviations of this actual travel from the corresponding equivalent travel are referred to as throttle deviation e and brake deviation f, respectively, wherein,

e=|P _Q0 -P _Q |；

f=|T _Q0 -T _Q |；

the limit values of the travel deviations e and f are set as e ₁ 、f ₁ And e is a ₁ >0，f ₁ >0；

Brake synchronous control, controlling the travel of the Q-wire brake pedal of the vehicle to the equivalent travel T _Q ；

Driving feedback control when d < d ₀ When the accelerator pedal by wire of the vehicle Q is controlled, the accelerator stroke is reduced, and when d is more than d ₀ When the throttle is in the closed state, the throttle stroke is increased;

brake feedback control when d > d ₀ Time, controlThe brake-by-wire pedal of the vehicle Q reduces the braking stroke when d < d ₀ When the brake is started, the brake stroke is increased;

the specific control execution method comprises the following steps:

when e is>=e ₁ And d is ₁ <=d<=d ₂ When the driver is started, driving synchronization control is executed;

when 0 is present<=e<e ₁ And d is d ₁ <=d<=d ₂ And P is _Q0 >When 0 is needed; or when d>d ₂ When the current is over; performing drive feedback control;

when P is _Q0 =T _Q0 =0, and d>=d ₀ When the driving feedback control is executed; when P is present _Q0 =T _Q0 =0, and d<d ₀ When the braking feedback control is executed.