WO2023125754A1

WO2023125754A1 - Automatic platooning vehicle system and control method

Info

Publication number: WO2023125754A1
Application number: PCT/CN2022/143170
Authority: WO
Inventors: 刘滨; 郭洁琼; 刘丝雨
Original assignee: 苏州立方元智能科技有限公司
Priority date: 2021-12-31
Filing date: 2022-12-29
Publication date: 2023-07-06
Also published as: CN114162123B; CN114162123A

Abstract

An automatic platooning vehicle system, comprising several platooning vehicles, a positioning and steering control module, a cooperative driving and braking module, a safety module, hinge members and a charging module; and a control method for the automatic platooning vehicle system, which employs the driving of each module to achieve the safe and balanced automatic platooning of multiple vehicles on the same track.

Description

An automatic platoon vehicle system and control method

technical field

The invention relates to the technical field of vehicle engineering, in particular to an automatic platoon vehicle system and a control method.

Background technique

Reducing the driver's driving load, reducing energy consumption, and improving road traffic efficiency are the three major directions and goals of automotive technology development. First, at present, the research and development hotspots to solve the driver's load are assisted driving ADAS and unmanned driving technology. However, this research direction is not yet mature, and there are great safety risks. Mature application, large-scale application is far away; Second, energy saving and consumption reduction is another direction for the development of automobile technology. Our country will propose a phased energy saving and emission reduction goal every five years. The existing energy saving and emission reduction methods Including electrification, hybrid power, active grille, various engine fuel-saving technologies, vehicle kinematics control, etc.; each technology can achieve certain results, but the existing energy-saving technologies are more or less close to the bottleneck The pioneering new energy-saving technology route is an important means to further reduce the energy consumption of automobiles and break through the bottleneck of energy saving and consumption reduction; third, the road traffic efficiency not only directly affects the driving experience of the people, but also directly affects the national economy The operating efficiency of the car will also have a direct impact on the energy consumption of the car.

According to incomplete statistics, my country's annual traffic flow is about 1.3 trillion vehicle kilometers, and the total cost of driving manpower is more than 1.5 trillion; the energy consumption of automobiles is more than 1 trillion, and the investment in new road infrastructure is more than 500 billion. If a new vehicle technology can be developed and a new driving scheme can be realized, the driving load and labor cost of the vehicle can be reduced, the energy consumption of driving can be reduced, and the traffic efficiency can be improved, which may bring huge economic and social benefits; therefore, the present invention has developed a An automatic platoon vehicle system and a control method to solve the problems existing in the prior art, but no technical solution identical or similar to the present invention has been found after searching.

technical solution

The purpose of the present invention is to provide a system and control method for automatically platooning vehicles to solve the safety problems caused by the driver's load when the vehicles are running in the prior art, the problem of high energy consumption when the vehicles are running, and the relatively low traffic efficiency. low problem.

The technical solution of the present invention is: an automatic train vehicle system, comprising:

A number of vehicles traveling in a row, including the leading vehicle and several following vehicles, wherein the total number of vehicles is set to N, N≥2, and the center point of the front axle of the Qth vehicle in the driving queue is set to F _Q , the Qth vehicle is marked as vehicle Q, 1<Q≤N, where N and Q are both natural numbers; the center point of the front axle of the pilot car is F ₁ ;

The positioning and steering control module is implanted in all vehicles, based on the coordinate system of each following vehicle, by obtaining a set of coordinate points passed by the center point F ₁ of the front axle of the leading vehicle during driving, and fitting out the coordinates of each following vehicle accordingly. The driving trajectory of the center point F _Q of the front axle, according to which the steering of the following vehicle is controlled;

Coordinated driving and braking modules, the following car maintains the same motion characteristics as the leading car through driving and braking operations.

Preferably, the positioning and steering control module includes a camera, a number of positioning marking codes A installed on the front of the vehicle, a gyroscope, a ranging sensor, a vehicle speed sensor, an electric steering wheel, an electric steering mechanism, and a following vehicle steering controller. A number of positioning mark codes B at the rear of the vehicle; where a set of positioning mark codes A installed at the front of the vehicle Q in the traffic queue is denoted as A _Q , and a set of positioning mark codes B installed at the rear of the vehicle Q is denoted as B _Q ;

The coordinated driving and braking module includes following vehicle distance sensors, following vehicle electric accelerator pedals, following vehicle electric brake pedals, pilot vehicle cooperative controllers, and following vehicle cooperative controllers installed on each following vehicle.

Preferably, a safety module is further included, the safety module includes a pilot car safety module and a follower car control module; the follower car control module performs synchronous control on the follower car according to the safety information sent by the lead car safety module.

Preferably, the pilot car safety module includes signal light information, braking information, and active safety control information, wherein the signal light information includes turn signal information, brake light information, emergency double-jump light information, and fog light information; The following car control module includes a following car signal light control module, a following car braking module, a following car airbag module, a following car seat belt control module, and a following car emergency call module.

Preferably, a hinge and a charging module are also included;

The hinge is installed between adjacent vehicles, including a front connector, a rear connector, an intermediate link, a magnetic coupling, and a straight spring piece; the front connector is fixed at the rear of the front vehicle , the rear connecting piece is fixed at the front of the rear vehicle, one end of the middle link is hinged to the front connecting piece, and the other end is hinged to the magnetic coupling, and the magnetic coupling and the rear connecting piece are magnetically adsorbed Coupling is realized; the straight spring pieces are arranged in two places, one is installed between the front connecting piece and the middle connecting rod, and the other is installed between the magnetic coupling and the middle connecting rod;

The charging module has a power line and a signal line built in the hinge, and when the magnetic coupling is suction-coupled to the rear connector, the connection of power and signals between adjacent vehicles is completed.

Preferably, the hinge further includes a pair of limit energy-absorbing blocks, the pair of limit energy-absorbing blocks are fixed on the middle link, and are arranged in a V shape, and the opening direction of the V shape faces the vehicle in front.

Based on the above-mentioned automatic platooning vehicle system, the present invention has also developed a control method for the automatic platooning vehicle system, and the control method is specifically as follows:

a. The positioning and steering control method of the vehicle Q;

(1) Define the coordinate system and time series. All following vehicles take the center point of their own front axle as the coordinate origin, define the center point of the front axle of vehicle Q as F _Q , and set it as the coordinate origin of vehicle Q, and establish coordinates The system Z _Q , where the positive direction of the Y axis is along the direction of the vehicle body and facing the front of the vehicle, and the positive direction of the X axis is perpendicular to the direction of the vehicle body and facing the right side of the vehicle body; any moment is defined as time k, and becomes k after time Δt +1 moment;

(2) Initialization, k=0;

(3) After a certain time Δt, the time changes from time k to time k+1, that is, k=k+1;

(4) Calculate the coordinate value F _1k (x _1k , y _1k ) of the center point F ₁ of the front axle of the pilot vehicle under the coordinate system Z _Q ;

(5) Estimate the transformation parameters of the coordinate system, and calculate the change parameters of the coordinate system Z _Q from time k-1 to time k, where the horizontal rotation angle of the vehicle Q from time k-1 to time k is calculated, that is, the rotation angle of the coordinate system is θ _Qk , based on the motion parameters of the vehicle and the time interval Δt, the X-axis change a and the Y-axis change b of the coordinate origin can be estimated; parameters a, b and θ _Qk constitute the transformation parameters of the coordinate system;

(6) Transform the coordinate system Z _Q , put the trajectory point F ₁ (F _1k-1 , F _1k-2 ,..., F _1k-n ) acquired before and including time k-1 at time k-1 The coordinate value under the time coordinate system is transformed into the coordinate value under the current k time coordinate system, wherein, the coordinate origin is transformed from F _Qk-1 to F _Qk , the rotation angle θ _Qk of the coordinate system, according to the coordinate system transformation equation, the transformed X Axis and Y-axis coordinate values are:

x _1m = (x _1m -a)*cosθ _Qk + (y _1m -b)*sinθ _Qk ;

y _1m = (y _1m -b)*cosθ _Qk -(x _1m -a)*sinθ _Qk ;

Among them, the coordinate values x _1m and y _1m on the left and right sides of the equation are the coordinate values of the trajectory point F _1m in the coordinate system at time k and k-1 respectively, and the values of m are k-1, k-2, ... , kn, and ensure that the Y-axis coordinate value after coordinate transformation y _1m >0, when y _1m <0, the point is already behind the front axle of the vehicle;

(7) In the coordinate system at time k, based on the n+1 track points F _1k passed by the center point F 1 of the front axle _of the pilot vehicle, and the coordinate values of F _1k-1 , F _1k-2 ,..., F _1k-n , fitting the trajectory R _Qk of the vehicle Q;

(8) The steering controller of the following vehicle controls the steering of the electric steering wheel installed on the vehicle Q according to the traveling trajectory R _Qk ;

(9) If the vehicles exit the platoon driving state, the step ends; if the vehicles continue to drive in platoon, return to step (3);

b. Coordinated driving and braking control method for vehicle Q:

It is controlled by collecting the braking and driving information of the pilot car and the distance between the front and rear cars.

Preferably, the vehicle Q also has any other axis, set its center point as F _Q ', and take this point as the origin of the coordinates, the X axis and the Y axis are in the same direction as the coordinate system Z _Q , and establish the coordinate system Z _Q ', both the positioning and steering modules can determine a set of coordinate points that the center point F ₁ of the front axle passes through under the coordinate system Z _Q ' during the driving process of the pilot car, and F _Q ' is based on the corresponding coordinate values of this set of coordinate points, Fit the corresponding driving trajectory, and control the electric steering mechanism corresponding to the axis according to the trajectory, so that the center point F _Q ' of the axis travels according to this trajectory.

Preferably, in the positioning and steering control method of the vehicle Q, in step (4), the coordinate value F _1k (x _1k , y _1k ) of the center point F ₁ of the front axle of the pilot vehicle under the coordinate system Z _Q is calculated The method is:

(1) Determine the relative geometric positional relationship between the front and rear vehicles among the Q vehicles in front, and the determination method includes any one or a combination of visual positioning, radio frequency positioning, ultrasonic positioning, laser positioning, and mechanical positioning;

(2) Calculate the coordinate value F _1k (x _1k , y _1k ) of F ₁ in the Z _Q coordinate system based on the relative geometric positional relationship between the front and rear vehicles obtained above and the body size chain.

Preferably, in the step (1), the method for confirming the relative geometric positional relationship of the front and rear vehicles is:

Set two ranging sensors at the rear of the vehicle, and the distances between them and the midpoint of the rear of the vehicle are L ₁ , L ₂ , and the distances to the rear vehicles are L ₃ , L ₄ ;

A distance sensor is arranged at the front center of the vehicle, and the distance measured from the rear of the front vehicle is _L5 ;

According to L ₁ , L ₂ , L ₃ , L ₄ , and L ₅ , the geometric positional relationship of the front and rear vehicles can be calculated, and the coordinate values of the two ranging sensors at the rear of the vehicle in front can be determined in the coordinate system of the adjacent vehicle behind it.

Preferably, in the step (1), the method for confirming the relative geometric position relationship of the front and rear vehicles is:

From the second car to the Qth car, the cameras on the following cars simultaneously take photos of the positioning mark A installed on the front of the car body and the positioning mark B installed on the rear of the vehicle in front, and a total of Q- Geometric positional relationship between 1 group of positioning mark code A at the front of the rear vehicle and positioning mark code B at the rear of the front vehicle, namely: positioning mark codes A ₂ and B ₁ , A ₃ and B ₂ , ..., A _Q and B _{Q- 1} , wherein the positioning mark code B at the tail of the pilot vehicle is defined as _B1 ;

In the step (2), the calculation method of the coordinate value F _1k (x _1k , y _1k ) of F ₁ is:

The positioning mark code A _Q and the positioning mark code B _Q are calibrated in advance under the coordinate system Z _Q , so the relative positional relationship between the positioning mark code A _Q and the positioning mark code B _Q is definite; based on this, the center of the front axle of the pilot vehicle The positional relationship between point F ₁ and the positioning mark code B ₁ at its rear is known, and the positional relationship between the positioning mark code A at the front of the same following vehicle and the positioning mark code B at the rear is known, namely: A ₂ and B ₂ , A ₃ and B ₃ ,..., A _Q-1 and B _Q-1 are known; thus the center point F ₁ and The geometric positional relationship between the positioning marks A _{and Q} at the front of the vehicle Q, since the coordinates of the positioning marks A _Q in the coordinate system Z _Q are known, it can be solved to calculate the front axle of the pilot vehicle at time k The coordinate value F _1k (x _1k , y _1k ) of the central point F ₁ in the coordinate system Z _Q.

Preferably, in the positioning and steering control method of the vehicle Q, in step (5), the solution method of the rotation angle θ _Qk of the vehicle Q is:

A gyroscope is installed on the vehicle Q, and the gyroscope monitors its angular velocity as ω _Qk at time k, and the rotation angle of vehicle Q from time k-1 to time k is θ _Qk =Δt*ω _Qk .

Preferably, in the positioning and steering control method of the vehicle Q,

In step (5), the solution method of the rotation angle θ _Qk of the vehicle Q is to install a wheel speed sensor on the vehicle Q, and the wheel speed sensor measures the wheel speeds of the left and right wheels on the same axle at time k as v _a and v _b respectively, Calculate the rotation angle θ _Qk = arcsin[Δt* (v _b- v _a )/ L ₆ ] based on the wheel speed difference and the wheel spacing L ₆ .

In the step (5), a calculation method for the X-axis and Y-axis changes a and b of the coordinate origin is:

X-axis variation a=-Δt*v _Qk *sinθ _Qk ,

Y-axis variation b=Δt*v _Qk *cosθ _Qk ;

In the step (6), the value method of the number n of track points that need coordinate transformation is as follows, and ensure that the Y-axis coordinate value y _1m >0 after the coordinate transformation, when y _1m <0, the point at this time Already following the rear of the front axle.

Preferably, when the cooperative driving and braking module is working, the method of controlling by collecting the braking driving information of the pilot car and the distance between front and rear vehicles is as follows:

(1) The cooperative controller of the leading car and the cooperative controller of the following car respectively collect the corresponding vehicle speed, brake pedal stroke, and accelerator pedal stroke data, and have the function of information transmission;

(2) Set the inter-vehicle distance to d ₀ . When driving, follow the car to read the accelerator pedal stroke of the pilot car and follow its changes. At the same time, observe the real-time inter-vehicle distance d to the vehicle in front. When d<d ₀ , reduce the accelerator stroke, when d>d ₀ , increase the throttle stroke;

(3) Set the inter-vehicle distance to d ₀ , and when braking, the following car reads the driving data transmitted by the cooperative controller of the pilot car, reads the brake pedal stroke of the pilot car, and follows its change, while observing the real-time Inter-vehicle distance d, when d>d ₀ , reduce the braking stroke, and when d<d ₀ , increase the braking stroke.

Preferably, a safety control method for the vehicle Q is also included, specifically as follows:

(1) The following car reads the signal light information of the leading car, and synchronously controls the various signal lights of the car through the signal light control module of the following car;

(2) The following car reads the braking information of the leading car, and brakes the car according to the braking stroke of the leading car and the distance between adjacent cars;

(3) Active safety control information. When the leading car activates ABS, ESP, or triggers the airbag or pre-tightens the seat belt, the following car passes over the control module of the car and directly starts the related modules synchronously.

Preferably, the control method of the hinge and the charging module of the vehicle Q is also included, specifically as follows:

The magnetic coupling and the rear connector can be connected manually or automatically when driving. As for the automatic lap connection during driving, when driving in a row, the rear vehicles will take the initiative under the control of the positioning and steering module Follow the vehicle in front, when the vehicle in front travels in a straight line, the vehicle in front, the vehicle in the rear and the hinge move on the same axis, when the vehicle in the rear keeps approaching the vehicle in front, the magnetic coupling and the rear connector are adsorbed and coupled, and Complete the docking of power and signals between the front vehicle and the rear vehicle.

Beneficial effect

Compared with prior art, the advantage of the present invention is:

The invention does not depend on the earth coordinate system and the geographical coordinate information of the vehicle, and can solve the driving trajectory of each following vehicle based on the vehicle's own coordinate system, and realize the automatic driving of multiple vehicles in parallel on the same trajectory through the steering control of the vehicle, and at the same time optimize the The driving and braking coordination and safety of the vehicle realize the automatic connection of the vehicle. Vehicle platooning can significantly reduce labor and energy costs.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment:

Fig. 1 is a schematic structural view of an automatic platooning vehicle system according to the present invention;

Fig. 2 is a schematic structural view of the hinge of the present invention;

Fig. 3 is a flow chart of the positioning and steering control method of the vehicle Q in the control method of the automatic platooning vehicle system according to the present invention;

Fig. 4 is the principle diagram that the present invention adopts ranging sensor to confirm the relative geometric positional relationship of front and rear vehicles;

Fig. 5 is that the present invention calculates the change schematic diagram of the coordinate system from the k-1 moment to the k moment according to the coordinate change amount of the center point F _Q of following the car front axle;

Fig. 6 is a traveling track diagram fitted when the following vehicle follows the pilot vehicle according to the present invention;

Fig. 7 is a schematic diagram of the structure of the vehicle when the hinges of the present invention are automatically docked.

Among them: 1. Vehicle, 11. Pilot car, 12. Follower car, 13. Camera, 14. Positioning mark code A, 15. Positioning mark code B;

2, hinge, 21, front side connector, 22, rear side connector, 23, middle connecting rod, 24, magnetic coupling, 25, straight spring leaf, 26, limit energy-absorbing block.

Embodiments of the present invention

Detailed ways

Below in conjunction with specific embodiment, content of the present invention is described in further detail:

An automatic platoon vehicle system includes several platoon vehicles 1, a positioning and steering control module, a cooperative driving and braking module, a safety module, a hinge and a charging module.

As shown in Figure 1, a number of vehicles 1 traveling in a row, including a leading vehicle 11 and a number of following vehicles 12, wherein the total number of vehicles is set to N, N≥2, and the Qth vehicle in the driving queue is set The center point of the front axle of the pilot car 11 is F _Q , and the Qth vehicle is recorded as vehicle Q, 1<Q≤N, where N and Q are both natural numbers; the center point of the front axle of the pilot car 11 is F ₁ ; when driving, the pilot car 11 manned or unmanned, following car 12 unmanned.

The positioning and steering control module is implanted in all vehicles 1. The positioning and steering of the pilot vehicle 11 is completed by the driver, or it can be completed by unmanned driving. The steering control of the following vehicle 12 is automatically completed by the positioning and steering control module. The car's own coordinate system, by obtaining a group of coordinate points passed by its front axle center point _F1 during the driving process of the pilot car 11, and fitting out the driving trajectory of each follower car 12 front axle center point F _Q accordingly, according to this The trajectory control follows the steering of the car; specifically, the positioning and steering control module includes a camera 13, a number of positioning marking codes A14 installed on the front of the vehicle, a gyroscope, a distance sensor, a vehicle speed sensor, an electric steering wheel, an electric steering mechanism, and a following The car steering controller is installed on some positioning mark codes B15 at the rear of the vehicle; wherein, the camera 13 installed on the following car 12 can be a binocular camera or a monocular camera; A set of positioning marking codes A14 is denoted as positioning marking codes A _Q , and a set of positioning marking codes B15 mounted on the rear of the vehicle Q is denoted as positioning marking codes B _Q .

Cooperate with the driving and braking module, the following car 12 maintains the same motion characteristics as the leading car 11 through driving and braking operations, and the motion characteristics include speed, acceleration, etc.; specifically, it includes the distance sensor of the following car, the electric accelerator pedal of the following car, The electric brake pedal of the following car, the cooperative controller of the leading car, and the cooperative controller of the following car; the distance sensor of the following car can be a non-contact sensor such as an infrared sensor, an ultrasonic sensor, a laser sensor, or a contact structure, such as a hinge The inter-vehicle distance is calculated by measuring the angle and size between the components of the hinged structure.

The safety module includes the safety module of the pilot car and the control module of the following car. The control module of the following car synchronously controls the following car according to the safety information sent by the safety module of the pilot car; the safety module of the pilot car includes signal light information, brake information, Active safety control information, signal light information includes turn signal information, brake light information, emergency double-jump light information, fog light information; following vehicle control module includes following vehicle signal light control module, following vehicle braking module, following vehicle airbag module , Following vehicle safety belt control module, Following vehicle emergency call module.

The hinge and the charging module, as shown in Figure 1 and Figure 2, the hinge 2 is installed between adjacent vehicles 1, including the front connector 21, the rear connector 22, the middle link 23, the magnetic coupling Part 24, straight spring piece 25; front side connecting piece 21 is fixed on the front vehicle rear portion, and rear side connecting piece 22 is fixed on the rear vehicle front portion, and is trumpet-shaped, is used for realizing guiding effect; Middle connecting rod 23 one ends and The front connector 21 is hinged, and the other end is hinged with the magnetic coupling 24. The magnetic coupling 24 and the rear connector 22 are coupled by magnetic force. At this time, the trumpet-shaped rear connector 22 is magnetically coupled. The piece 24 plays a guiding role when it is docked and adsorbed; there are two straight spring pieces 25, one is installed between the front connecting piece 21 and the middle connecting rod 23, and the other is installed between the magnetic coupling 24 and the middle connecting rod 23; under the action of no external force, ensure that the components in the hinge are arranged along the same axis; the charging module has a power line and a signal line built in the hinge, and the magnetic coupling 24 and the rear connector 22 Complete the docking of power and signals between adjacent vehicles during adsorption coupling.

As a further optimization, as shown in Figure 2, the hinge also includes a pair of limit energy-absorbing blocks 26, and a pair of limit energy-absorbing blocks 26 are fixed on the middle connecting rod 23, and are arranged in a V shape. The direction of the type opening faces the vehicle in front; its function is to limit the operating range of the hinge, thereby controlling the vehicle distance and attitude between the pilot car 11 and the following car 12, and preventing the two cars from colliding; in an emergency, such as the pilot car 11 In the event of a collision, when the following car 12 rear-ends the vehicle in front, the limit energy-absorbing block 26 is crushed, and the middle connecting rod 23 is bent, which can play an energy-absorbing role, thereby protecting the driver and passengers to a certain extent .

a, as shown in Figure 3, the positioning and steering control method of the vehicle Q, the specific steps are as follows;

(S01) Define the coordinate system and time series. All following vehicles take the center point of their own front axle as the coordinate origin, define the center point of the front axle of vehicle Q as F _Q , and set it as the coordinate origin of vehicle Q, and establish coordinates The system Z _Q , where the positive direction of the Y axis is along the direction of the vehicle body and facing the front of the vehicle, and the positive direction of the X axis is perpendicular to the direction of the vehicle body and facing the right side of the vehicle body; any moment is defined as time k, and becomes k after time Δt +1 moment;

(S02) initialization, k=0;

(S03) After a certain time Δt, the time changes from time k to time k+1, that is, k=k+1;

(S04) Calculate the coordinate value F _1k (x _1k , y _1k ) of the center point F ₁ of the front axle of the pilot vehicle under the coordinate system Z _Q , the specific method is:

Step 1: Determine the relative geometric positional relationship between the front and rear cars among the front Q vehicles. The determination method includes any one or combination of visual positioning, radio frequency positioning, ultrasonic positioning, laser positioning, and mechanical positioning;

Step 2: Calculate the coordinate value F _1k (x _1k , y _1k ) of F ₁ in the Z _Q coordinate system based on the relative geometric positional relationship between the front and rear vehicles obtained above and the body size chain.

Regarding the first step above, the following methods can be used to confirm the relative geometric position relationship of the front and rear vehicles:

As shown in Figure 4, two ranging sensors are installed at the rear of the vehicle, that is, S ₁ and S ₂ in the figure, and the distances between them and the midpoint of the rear of the vehicle are L ₁ and L ₂ respectively, and the distances from the rear of the vehicle are respectively measured. The distance of the vehicle is L ₃ , L ₄ ; set a distance sensor at the center of the front of the vehicle, that is, S ₃ in the figure, and measure the distance to the rear of the vehicle in front as L ₅ ; according to L ₁ , L ₂ , L ₃ , L ₄ , L ₅ can calculate the geometric positional relationship of the front and rear vehicles, and can determine the coordinate values of the two distance measuring sensors at the rear of the front vehicle in the coordinate system of the adjacent vehicle behind it.

It should be noted that in order to ensure the calculation accuracy, the three ranging sensors and the midpoint of the rear of the front vehicle are all set in the same horizontal plane; way of the distance sensor.

Regarding the first step above, another method can be used to confirm the relative geometric position relationship of the front and rear vehicles:

From the second car to the Qth car, the cameras on the following cars simultaneously take photos of the positioning mark A installed on the front of the car body and the positioning mark B installed on the rear of the vehicle in front, and a total of Q- Geometric positional relationship between 1 group of positioning mark code A at the front of the rear vehicle and positioning mark code B at the rear of the front vehicle, namely: positioning mark codes A ₂ and B ₁ , A ₃ and B ₂ , ..., A _Q and B _Q- The geometric position of ₁ is off, wherein the positioning mark code B at the tail of the pilot vehicle is defined as _B1 ;

In the corresponding second step, the calculation method of the coordinate value F _1k (x _1k , y _1k ) of F ₁ is:

(S05) Calculating the transformation parameters of the coordinate system, and calculating the change parameters of the coordinate system Z _Q from time k-1 to time k;

As shown in Figure 5, F _Qk-1 is the position of point F _Q at time k-1, and F _Qk is the position of point F _Q at time k; solve the angle θ _Qk of vehicle Q from time k-1 to time k, and install Since the vehicle speed sensor of the vehicle Q monitors the speed of the center point F _Q of the front axle at time k is v _Qk , when it is assumed that the trajectory of the F _Q can be simplified as a broken line composed of straight line segments, the change of the coordinate origin F _Q is a The calculation method is as follows:

X-axis variation a=-Δt*v _Qk *sinθ _Qk ,

Y-axis variation b=Δt*v _Qk *cosθ _Qk ;

In the formula, there are two ways to solve the rotation angle θ _Qk of the vehicle Q as follows:

First, a gyroscope is installed on the vehicle Q. The gyroscope monitors its angular velocity at time k as ω _Qk , and the rotation angle of vehicle Q from time k-1 to time k is θ _Qk =Δt*ω _Qk ;

In this method, the reason for the "-" in the X-axis variation is that when the gyroscope is used to measure the rotation angle of the following car, based on the three-dimensional coordinate system, where the Z-axis is perpendicular to the ground and faces upward, according to the principle of the right-hand rule, when the vehicle When turning left, the measured angle is positive, and the change of the coordinates in the X-axis direction is negative; when the vehicle turns right, the measured angle is negative, and the coordinates are in the X-axis direction. The amount of change is a positive value.

Second, a wheel speed sensor is installed on the vehicle Q, and the wheel speed sensor measures _the wheel speeds of the left and right wheels on the same axle at time k as v _a and v _b respectively, and the rotation angle θ _Qk = arcsin [Δt* (v _{b -} v _a )/ L ₆ ].

In this method, the reason for the "-" in the X-axis variation is: since the vehicle’s left wheel speed is v _a , and the right wheel speed is v _b , when the vehicle turns left, v _a < v _b , the calculated The turning angle is a positive value, and the change of the coordinates in the X-axis direction is a negative value at this time; when the vehicle turns right, the calculated angle is a negative value, and the change of the coordinates in the X-axis direction is a positive value at this time.

It should be pointed out that the parameters a and b have multiple calculation methods depending on the assumed conditions. For example, when the trajectory of the assumed coordinate origin F _Q is a curve, the calculation methods of the parameters a and b also need to be changed. In this embodiment, A relatively simple assumption and calculation method are provided;

(S06) Transform the coordinate system Z _Q , and place the track point F ₁ (F _1k-1 , F _1k-2 ,..., F _1k-n ) obtained before and including time k-1 at time k-1 The coordinate value under the time coordinate system is transformed into the coordinate value under the current k time coordinate system, wherein, the coordinate origin is transformed from F _Qk-1 to F _Qk , the rotation angle θ _Qk of the coordinate system, according to the coordinate system transformation equation, the transformed X Axis and Y-axis coordinate values are:

x _1m = (x _1m -a)*cosθ _Qk + (y _1m -b)*sinθ _Qk ;

y _1m = (y _1m -b)*cosθ _Qk -(x _1m -a)*sinθ _Qk ;

From the above steps, it can be seen that the initial coordinate value of any track point is obtained in step (S04), and a total of n times of coordinate transformations have been carried out during the process of vehicle Q approaching the track point. Due to the influence of various factors, each coordinate transformation There will be a certain error, but due to the limited number of transformations and limited error accumulation, a higher trajectory calculation accuracy can be obtained. The existing inertial navigation technology is based on the geodetic coordinate system for mileage integration calculations, and the SLAM optical positioning real-time mapping technology is similar, which will produce irreversible error accumulation; When performing navigation and positioning, the lateral deviation of the vehicle is at least 1 meter every 1 kilometer, 10 meters for 10 kilometers, and 100 meters for 100 kilometers. This level of accuracy is completely unacceptable, and 10 meters is equivalent to the deviation of three lanes; The calculation deviation of the trajectory point is positively correlated with the length of the queue. The calculation deviation of the trajectory point is about 3-5 cm when the length of the queue is 30 meters, and there will be no error accumulation with the increase of the driving mileage, which is completely in line with the queue driving. Vehicle track point positioning accuracy requirements; professional and technical personnel in this field can easily understand, compared with the optical positioning commonly used in smart cars in the prior art, whether it is device cost, computing power requirements and system delay, or infrastructure The investment is not the same, and the related technologies of the present invention all have orders of magnitude advantages.

(S07) In the coordinate system at time k, based on the n+1 track points F _1k passed by the center point F 1 of the front axle _of the pilot vehicle, and the coordinate values of F _1k-1 , F _1k-2 ,..., F _1k-n , fitting the trajectory R _Qk of the vehicle Q;

(S08) The steering controller of the following vehicle controls the steering of the electric steering wheel mounted on the vehicle Q according to the traveling trajectory R _Qk ;

(S09) If the vehicles exit the platoon driving state, the step ends; if the vehicles continue to drive in platoon, return to the step (S03).

As shown in Fig. 6, the trajectory fitting method of vehicle Q is as follows: based on the vehicle Q coordinate system, starting from the center point F _Q of the front axle of the vehicle, refer to the trajectory point F _1k of the passing point of the center point F ₁ of the leading vehicle front axle , F _1k-1 , F _1k-2 ,..., F _1k-n , fit a curved trajectory R _Qk , and ensure that the deviation value of the coordinates of each point passed by F ₁ from the curved trajectory is less than the set value e, usually In the case of e≤10cm, but not limited to this range; at the same time, the total curvature change of the curved trajectory should be as small as possible, that is, the total rotation angle of the electric steering wheel is the smallest during driving; after the calculation of the curved trajectory is completed, the curved trajectory is the following car The following vehicle steering controller controls the electric steering wheel.

Vehicle Q also has any other axis, set its center point as F _Q ', and take this point as the coordinate origin, X axis, Y axis and coordinate system Z _Q are in the same direction, establish coordinate system Z _Q ', positioning and steering All the modules can determine a set of coordinate points that the center point F ₁ of the front axle passes under the coordinate system Z _Q ' during the driving process of the pilot car, and F _Q ' fits the corresponding The driving trajectory, and control the electric steering mechanism corresponding to the axis according to the trajectory, so that the center point F _Q ' of the axis travels according to this trajectory.

b. Coordinated driving and braking control method for vehicle Q:

It is controlled by collecting the braking and driving information of the pilot car and the distance between the front and rear cars. The specific control method is as follows:

c. Safety control method for vehicle Q:

(2) The follower car reads the braking information of the pilot car, and brakes the car according to the braking stroke of the pilot car and the distance between adjacent cars; when the braking stroke of the pilot car exceeds a certain set value s, for example, s=90 %, the following car directly operates the braking stroke to 100%; when the inter-vehicle distance d is less than a certain safety value d ₁ , no matter whether the leading car is in the driving or braking state, it will start to brake, and the following car will start to brake as the d value decreases. And increase the braking stroke until d>d ₁ ;

d. The control method of the hinge and the charging module of the vehicle Q:

The magnetic coupling 24 and the rear connector 22 can be connected by manual lapping or automatic lapping during driving. Regarding the automatic lapping connection during driving, when driving in a row, the rear vehicles are positioned and controlled by the steering module. Actively follow the front vehicle to run, as shown in Figure 7, when the front vehicle is running in a straight line, the front vehicle, the rear vehicle and the hinge move on the same axis, and when the rear vehicle is constantly approaching the front vehicle, the magnetic coupling 24 and The rear side connector 22 is adsorbed and coupled, and completes the docking of power and signals between the front vehicle and the rear vehicle; the positioning accuracy of the present invention is at the millimeter level, so it is easy to realize automatic docking when the vehicle is running at a low speed.

It should be pointed out that a key and outstanding innovation of the present invention is that the positioning and steering control method of the vehicle Q "does not need" the earth coordinate system, nor does it need the geographical coordinate information of the vehicle, but is based on the own coordinate system of each following vehicle, Through the workshop positioning, according to the motion parameters of the vehicle, the coordinate transformation is carried out continuously, so as to obtain the real-time "dynamic" trajectory of the vehicle, and the steering of the vehicle is controlled according to the deviation between each vehicle and its corresponding "dynamic" trajectory in the same coordinate system, so that the front and rear vehicles maintain the same Tracks are automatically driven in platoon. In the existing technology, in order to realize the same trajectory between vehicles, it needs to be based on the geodetic coordinate system, and use satellite positioning, laser radar, millimeter wave radar, high-definition camera, and often rely on ground-based positioning targets, vehicle-road coordination facilities, and high-precision The semantic map obtains the geographical coordinate information of the vehicle, and plans the vehicle trajectory to control the vehicle steering according to the geographical coordinate information; it is not difficult for professional and technical personnel in this field to understand that satellite positioning has low accuracy and is affected by factors such as ionosphere, troposphere, and environmental occlusion. The impact is relatively large, and the positioning accuracy is at the meter level, which is difficult to meet the centimeter-level positioning accuracy and positioning stability requirements of vehicles driving in a row; however, optical positioning has the defects of poor stability, low accuracy, huge computing power demand, and long delay. Vicious traffic accidents caused by the application of related technologies to smart cars are not uncommon; the investment in foundation facilities is huge, and the driving area of vehicles is limited; the vehicle positioning and steering control method proposed by the present invention is based on commonly used information such as vehicle motion parameters and workshop positioning , so that multiple vehicles can automatically drive in a row on ordinary roads on the same track, which not only has low cost and high precision, but also does not depend on any foundation facilities and has strong flexibility. Undoubtedly, the present invention is not an improvement and optimization of specific technical solutions under the existing technical route of automatic platooning of vehicles, but opens up a new technical route, which is an original invention.

At the same time, the present invention also optimizes the vehicle's cooperative driving and braking control method and safety control method, and designs an automatic vehicle connection mechanism, which effectively guarantees the safe, stable operation and convenient use of the vehicle system. Vehicles traveling in platoon can optimize the vehicle's fluid dynamics, reduce air resistance, and greatly reduce labor costs and energy costs during vehicle use.

Claims

An automatic platooning vehicle system, characterized in that it comprises:

A number of vehicles traveling in a row, including the leading vehicle and several following vehicles, wherein the total number of vehicles is set to N, N≥2, and the center point of the front axle of the Qth vehicle in the driving queue is set to F Q , the Qth vehicle is marked as vehicle Q, 1<Q≤N, where N and Q are both natural numbers; the center point of the front axle of the pilot car is F 1 ;

The positioning and steering control module is implanted in all vehicles, based on the coordinate system of each following vehicle, by obtaining a set of coordinate points passed by the center point F 1 of the front axle of the leading vehicle during driving, and fitting out the coordinates of each following vehicle accordingly. The driving trajectory of the center point F Q of the front axle, according to which the steering of the following vehicle is controlled;

Coordinated driving and braking modules, the following car maintains the same motion characteristics as the leading car through driving and braking operations.
A system for automatically platooning vehicles according to claim 1, characterized in that: the positioning and steering control module includes a camera, a number of positioning marking codes A installed on the front of the vehicle, a gyroscope, a distance measuring sensor, Vehicle speed sensor, electric steering wheel, electric steering mechanism, following car steering controller, several positioning mark codes B installed at the rear of the vehicle; among them, a group of positioning mark codes A installed at the front of vehicle Q in the driving queue is denoted as A Q , and the installation A group of positioning mark codes B at the rear of the vehicle Q is denoted as B Q ;

The coordinated driving and braking module includes following vehicle distance sensors, following vehicle electric accelerator pedals, following vehicle electric brake pedals, pilot vehicle cooperative controllers, and following vehicle cooperative controllers installed on each following vehicle.
A system for automatically platooning vehicles according to claim 1, characterized in that: it also includes a safety module, the safety module includes a pilot vehicle safety module and a following vehicle control module; the following vehicle control module is based on the pilot vehicle safety The safety information sent by the module performs synchronous control on the following vehicle.
An automatic platooning vehicle system according to claim 3, wherein the safety module of the pilot car includes signal light information, braking information, and active safety control information, wherein the signal light information includes turn signal information, Brake light information, emergency double-jump light information, fog light information; the following car control module includes a following car signal light control module, a following car braking module, a following car airbag module, a following car seat belt control module, a following car emergency call module.
An automatic platoon vehicle system according to claim 1, further comprising a hinge and a charging module;

The hinge is installed between adjacent vehicles, including a front connector, a rear connector, an intermediate link, a magnetic coupling, and a straight spring piece; the front connector is fixed at the rear of the front vehicle , the rear connecting piece is fixed at the front of the rear vehicle, one end of the middle link is hinged to the front connecting piece, and the other end is hinged to the magnetic coupling, and the magnetic coupling and the rear connecting piece are magnetically adsorbed Coupling is realized; the straight spring pieces are arranged in two places, one is installed between the front connecting piece and the middle connecting rod, and the other is installed between the magnetic coupling and the middle connecting rod;

The charging module has a power line and a signal line built in the hinge, and when the magnetic coupling is suction-coupled to the rear connector, the connection of power and signals between adjacent vehicles is completed.
An automatic platooning vehicle system according to claim 5, wherein the hinge further includes a pair of limit energy-absorbing blocks, and the pair of limit energy-absorbing blocks are fixed on the middle link , and set in a V-shape, with the V-shape opening facing the vehicle ahead.
A control method for an automatic platooning vehicle system based on any one of claims 1-6, characterized in that: the control method is specifically as follows:

a. The positioning and steering control method of the vehicle Q;

(1) Define the coordinate system and time series. All following vehicles take the center point of their own front axle as the coordinate origin, define the center point of the front axle of vehicle Q as F Q , and set it as the coordinate origin of vehicle Q, and establish coordinates The system Z Q , where the positive direction of the Y axis is along the direction of the vehicle body and facing the front of the vehicle, and the positive direction of the X axis is perpendicular to the direction of the vehicle body and facing the right side of the vehicle body; any moment is defined as time k, and becomes k after time Δt +1 moment;

(2) Initialization, k=0;

(3) After a certain time Δt, the time changes from time k to time k+1, that is, k=k+1;

(4) Calculate the coordinate value F 1k (x 1k , y 1k ) of the center point F 1 of the front axle of the pilot vehicle under the coordinate system Z Q ;

(5) Estimate the transformation parameters of the coordinate system, and calculate the change parameters of the coordinate system Z Q from time k-1 to time k, where the rotation angle of the vehicle Q from time k-1 to time k is calculated, that is, the rotation angle of the coordinate system is θ Qk , based on the motion parameters of the vehicle and the time interval Δt, the X-axis change a and the Y-axis change b of the coordinate origin can be estimated; the parameters a, b and θ Qk constitute the transformation parameters of the coordinate system;

(6) Transform the coordinate system Z Q , put the trajectory point F 1 (F 1k-1 , F 1k-2 ,..., F 1k-n ) acquired before and including time k-1 at time k-1 The coordinate value under the time coordinate system is transformed into the coordinate value under the current k time coordinate system, wherein, the coordinate origin is transformed from F Qk-1 to F Qk , the rotation angle θ Qk of the coordinate system, according to the coordinate system transformation equation, the transformed X Axis and Y-axis coordinate values are:

x 1m = (x 1m -a)*cosθ Qk + (y 1m -b)*sinθ Qk ;

y 1m = (y 1m -b)*cosθ Qk -(x 1m -a)*sinθ Qk ;

Among them, the coordinate values x 1m and y 1m on the left and right sides of the equation are the coordinate values of the trajectory point F 1m in the coordinate system at time k and k-1 respectively, and the values of m are k-1, k-2, ... ,kn;

(7) In the coordinate system at time k, based on the n+1 track points F 1k passed by the center point F 1 of the front axle of the pilot vehicle, and the coordinate values of F 1k-1 , F 1k-2 ,..., F 1k-n , fitting the trajectory R Qk of the vehicle Q;

(8) The steering controller of the following vehicle controls the steering of the electric steering wheel installed on the vehicle Q according to the traveling trajectory R Qk ;

(9) If the vehicles exit the platoon driving state, the step ends; if the vehicles continue to drive in platoon, return to step (3);

b. Coordinated driving and braking control method for vehicle Q:

It is controlled by collecting the braking and driving information of the pilot car and the distance between the front and rear cars.
A control method for an automatic platooning vehicle system according to claim 7, characterized in that: the vehicle Q also has any other axis, and its center point is set as F Q ', and this point is used as the coordinate The origin, X-axis, Y-axis and the coordinate system Z Q are in the same direction, and the coordinate system Z Q ' is established. The positioning and steering modules can determine the distance that the front axle center point F 1 passes under the coordinate system Z Q ' during the driving process of the pilot car. A set of coordinate points, F Q ', according to the coordinate values of the corresponding set of coordinate points, fit the corresponding driving trajectory, and control the electric steering mechanism corresponding to the axis according to the trajectory, so that the axis center point F Q ' Follow this track.
A control method for an automatic platoon vehicle system according to claim 7, characterized in that: in the positioning and steering control method of the vehicle Q, in step (4), the calculation is performed under the coordinate system Z Q , The method of the coordinate value F 1k (x 1k , y 1k ) of the center point F 1 of the front axle of the pilot vehicle is:

(1) Determine the relative geometric positional relationship between the front and rear vehicles among the Q vehicles in front, and the determination method includes any one or a combination of visual positioning, radio frequency positioning, ultrasonic positioning, laser positioning, and mechanical positioning;

(2) Calculate the coordinate value F 1k (x 1k , y 1k ) of F 1 in the Z Q coordinate system based on the relative geometric positional relationship between the front and rear vehicles obtained above and the body size chain.
A control method for an automatic platoon vehicle system according to claim 9, characterized in that: in the step (1), the method for confirming the relative geometric positional relationship of the front and rear vehicles is as follows:

Set two ranging sensors at the rear of the vehicle, and the distances from the midpoint of the rear of the vehicle are L 1 and L 2 respectively, and the distances to the rear vehicles are L 3 and L 4 respectively;

Set a distance sensor at the center of the front of the vehicle, and measure the distance to the rear of the vehicle in front as L5 ; according to L1 , L2 , L3 , L4 , and L5 , the geometric positional relationship between the front and rear vehicles can be calculated. Determine the coordinate values of the two ranging sensors at the rear of the front vehicle in the coordinate system of the adjacent vehicle behind it.
A control method for an automatic platoon vehicle system according to claim 9, characterized in that: in the step (1), the method for confirming the relative geometric positional relationship of the front and rear vehicles is as follows:

From the second car to the Qth car, the cameras on the following cars simultaneously take photos of the positioning mark A installed on the front of the car body and the positioning mark B installed on the rear of the vehicle in front, and a total of Q- Geometric positional relationship between 1 group of positioning mark code A at the front of the rear vehicle and positioning mark code B at the rear of the front vehicle, namely: positioning mark codes A 2 and B 1 , A 3 and B 2 , ..., A Q and B Q- 1 , wherein the positioning mark code B at the tail of the pilot vehicle is defined as B1 ;

In the step (2), the calculation method of the coordinate value F 1k (x 1k , y 1k ) of F 1 is:

The positioning mark code A Q and the positioning mark code B Q are calibrated in advance under the coordinate system Z Q , so the relative positional relationship between the positioning mark code A Q and the positioning mark code B Q is definite; based on this, the center of the front axle of the pilot vehicle The positional relationship between point F 1 and the positioning mark code B 1 at its rear is known, and the positional relationship between the positioning mark code A at the front of the same following vehicle and the positioning mark code B at the rear is known, namely: A 2 and B 2 , A 3 and B 3 ,..., A Q-1 and B Q-1 are known; thus the center point F 1 and The geometric positional relationship between the positioning marks A and Q at the front of the vehicle Q, since the coordinates of the positioning marks A Q in the coordinate system Z Q are known, it can be solved to calculate the front axle of the pilot vehicle at time k The coordinate value F 1k (x 1k , y 1k ) of the central point F 1 in the coordinate system Z Q.
A control method for an automatic platoon vehicle system according to claim 7, characterized in that: in the positioning and steering control method of the vehicle Q, in step (5), the calculation of the rotation angle θ Qk of the vehicle Q The method is:

A gyroscope is installed on the vehicle Q, and the gyroscope monitors its angular velocity as ω Qk at time k, and the rotation angle of vehicle Q from time k-1 to time k is θ Qk =Δt*ω Qk .
A control method for an automatic platoon vehicle system according to claim 7, characterized in that: in the vehicle Q positioning and steering control method,

In step (5), the solution method of the rotation angle θ Qk of the vehicle Q is to install a wheel speed sensor on the vehicle Q, and the wheel speed sensor measures the wheel speeds of the left and right wheels on the same axle at time k as v a and v b respectively, Calculate the rotation angle θ Qk = arcsin[Δt* (v b- v a )/ L 6 ] through the wheel speed difference and the wheel spacing L 6 ;

In the step (5), a calculation method for the X-axis and Y-axis changes a and b of the coordinate origin is:

X-axis variation a=-Δt*v Qk *sinθ Qk ,

Y-axis variation b=Δt*v Qk *cosθ Qk ;

In the step (6), the value method of the number n of track points that need coordinate transformation is as follows, and ensure that the Y-axis coordinate value y 1m >0 after the coordinate transformation, when y 1m <0, the point at this time Already following the rear of the front axle.
A control method for an automatic platoon vehicle system according to claim 7, characterized in that: when the cooperative driving and braking module is working, the control method is carried out by collecting the braking driving information of the pilot vehicle and the distance between front and rear vehicles for:

(1) The cooperative controller of the leading car and the cooperative controller of the following car respectively collect the corresponding vehicle speed, brake pedal stroke, and accelerator pedal stroke data, and have the function of information transmission;

(2) Set the inter-vehicle distance to d 0 . When driving, follow the car to read the accelerator pedal stroke of the pilot car and follow its changes. At the same time, observe the real-time inter-vehicle distance d to the vehicle in front. When d<d 0 , reduce the accelerator stroke, when d>d 0 , increase the throttle stroke;

(3) Set the inter-vehicle distance to d 0 , and when braking, the following car reads the driving data transmitted by the cooperative controller of the pilot car, reads the brake pedal stroke of the pilot car, and follows its change, while observing the real-time Inter-vehicle distance d, when d>d 0 , reduce the braking stroke, and when d<d 0 , increase the braking stroke.
A control method for an automatic platoon vehicle system according to claim 7, characterized in that: it also includes a safety control method for the vehicle Q, specifically as follows:

(1) The following car reads the signal light information of the leading car, and synchronously controls the various signal lights of the car through the signal light control module of the following car;

(2) The following car reads the braking information of the leading car, and brakes the car according to the braking stroke of the leading car and the distance between adjacent cars;

(3) Active safety control information. When the leading car activates ABS, ESP, or triggers the airbag or pre-tightens the seat belt, the following car passes over the control module of the car and directly starts the related modules synchronously.
A control method for an automatic platoon vehicle system according to claim 7, characterized in that: it also includes a control method for the hinge of the vehicle Q and the charging module, specifically as follows:

The magnetic coupling and the rear connector can be connected manually or automatically when driving. As for the automatic lap connection during driving, when driving in a row, the rear vehicles will take the initiative under the control of the positioning and steering module Follow the vehicle in front, when the vehicle in front travels in a straight line, the vehicle in front, the vehicle in the rear and the hinge move on the same axis, when the vehicle in the rear keeps approaching the vehicle in front, the magnetic coupling and the rear connector are adsorbed and coupled, and Complete the docking of power and signals between the front vehicle and the rear vehicle.

the