CN114999140B - Linkage control method for mixed traffic expressway down ramp and near signal control area - Google Patents

Abstract

The invention discloses a linkage control method for a mixed traffic expressway off ramp and a near signal control area, which comprises the following steps: s1: setting a mixed traffic scene of the connection of the expressway down ramp and the near signal control area; s2: establishing a linear vehicle longitudinal dynamics model by combining dynamics characteristics of a vehicle; s3: in order to ensure the stability of a motorcade, constructing a expressway off ramp and near signal control area linkage control method based on an information physical system in a mixed traffic scene; s31: in order to avoid long waiting time of heterogeneous vehicles in a link area and collision at a joint point, a first-in first-out cooperative control method is constructed; s32: in order to solve the phenomenon that a virtual motorcade stops when a near signal control area is constrained by the phase of a signal lamp, a distributed cooperative control method based on an information physical system is established.

Description

A linkage control method for mixed traffic expressway off-ramp and near signal control area

Technical Field

The present invention relates to the field of coordinated control of networked automatic vehicles and networked human drivers in mixed traffic, and in particular to a method for coordinated control of an off-ramp and a near-signal control area on a mixed traffic expressway.

Background technique

With the rapid development of autonomous driving technology and communication technology, networked autonomous driving cars and networked human-driven cars are gradually emerging and gaining popularity. Future traffic will be composed of networked autonomous driving cars and networked human-driven cars, forming a new type of mixed traffic, which will last for a long time. However, mixed traffic also has common problems similar to traditional traffic, such as traffic safety and traffic congestion. Therefore, it is worth exploring how to solve problems such as traffic safety and traffic congestion in a mixed traffic environment.

The ramp from the expressway to the city road is one of the complex traffic problems. For example, it is easy to cause traffic accidents and long waiting time, resulting in a decrease in the traffic efficiency of the entire road network. At the same time, when the vehicles on the expressway ramp merge with the vehicles on the city road, they are often restricted by traffic lights, which easily causes these vehicles to stop and start periodically, further aggravating the decrease in road traffic efficiency. In order to avoid collisions and long waiting times when vehicles on the expressway ramp enter the city road, the present invention proposes a mixed traffic expressway ramp and near signal control area linkage control method to ensure that the mixed vehicle group can pass the near signal control area consistently and stably under the constraints of traffic lights.

By consulting relevant literature and patents, few literatures have studied the linkage control problem between the off-ramp of expressway and the near signal control area. The present invention proposes a linkage control method between the off-ramp of mixed traffic expressway and the near signal control area, which can effectively ensure that the new fleet formed by the vehicles on the off-ramp of expressway entering the urban road passes through the near signal control area consistently and stably under the constraint of traffic lights, thereby improving the overall traffic efficiency of expressway and urban roads.

Summary of the invention

The purpose of the present invention is to provide a method for linkage control of mixed traffic expressway off-ramp and near signal control area, so as to avoid collision and long waiting time when vehicles on the expressway off-ramp enter urban roads, ensure that the new fleet formed by vehicles on the expressway off-ramp entering urban roads passes through the near signal control area consistently and stably under the constraints of traffic lights, and further improve the traffic efficiency and safety of the entire road network.

To achieve the above object, the present invention provides the following technical solution: a method for controlling the linkage between the ramp and the near signal control area of a mixed traffic expressway, the method comprising the following steps:

S1: Set up a mixed traffic scenario where the expressway off-ramp connects with the near signal control area;

S2: Based on the dynamic characteristics of the vehicle, a linear vehicle longitudinal dynamics model is established;

S3: In order to ensure the stability of the fleet, a linkage control method between the expressway off-ramp and the near-signal control area based on the cyber-physical system is constructed in a mixed traffic scenario.

Furthermore, the S3 specifically includes the following steps:

S31: To avoid long waiting time of heterogeneous vehicles in the link area and collision at the connection point, a first-in-first-out cooperative control method is constructed;

S32: In order to solve the problem of virtual fleets stopping and starting due to the phase constraints of traffic lights in the near-signal control area, a distributed collaborative control method based on cyber-physical systems is established.

Furthermore, the mixed traffic scene where the S1 expressway off-ramp connects with the near signal control area is set as follows:

The expressway ramp is connected to the city road to form a connection point. When the traffic volume is high, a conflict area will be formed. In addition, a traffic light is arranged in front of the city road connection point. There are m vehicles and n vehicles on the expressway ramp and the single lane of the city road respectively. The total number of vehicles is N = m + n, among which connected automatic vehicles and connected human drivers are mixed on the road. In such a scenario, the connected automatic vehicles and connected human drivers can obtain status information from each other through vehicle-to-vehicle communication. According to the obtained status information, the connected automatic vehicles can automatically adjust their own status, and the connected human drivers follow the status of multiple vehicles in front of it. In addition, all heterogeneous vehicles can obtain information from traffic lights.

Furthermore, the nonlinear longitudinal dynamics of the S2 vehicle is:

and _vi (t) represent the position and velocity of the i-th vehicle, is the mechanical efficiency of the transmission system. _ri represents the tire radius, _Ti (t) represents the actual driving/braking torque, _mi represents the vehicle mass, /> represents the aerodynamic drag coefficient, g represents the gravitational acceleration, _fi is the rolling resistance coefficient, θ( _pi (t)) represents the inclination angle of the road, _ζi represents the vehicle dynamics inertia delay, ^{and Tides} ₍ t) represents the desired driving/braking torque.

By using the linear feedback technique, the linear vehicle longitudinal dynamics model can be expressed as:

Where u _i (t) represents the control input of the vehicle;

When external factors are not considered, the linear dynamic model of the i-th vehicle degenerates into:

Where a _i (t) represents the acceleration of the i-th vehicle.

Furthermore, in S31, when vehicles on the expressway ramp enter the urban road, in order to avoid a long waiting time of heterogeneous vehicles in the link area and a collision at the connection point, a first-in-first-out collaborative control method is established, and the specific steps are as follows:

S311: At time t, heterogeneous vehicles in the link area obtain vehicle status information from each other through vehicle-to-vehicle communication;

S312: Using mapping technology, project the status information of the connected automatic vehicles and connected human vehicles on the off-ramp of the expressway onto the urban road, and sort the projected vehicles and the vehicles on the urban road according to a first-in-first-out collaborative algorithm to form a virtual fleet;

S313: To ensure that all heterogeneous vehicles in the virtual fleet can maintain the desired vehicle spacing and speed, we use an intelligent driver model, which is as follows:

Where _vi (t) is the speed of the i-th following vehicle at time t, _vmax is the maximum speed; △ _vi (t) and △ _si (t) represent the speed difference and distance between the i-th vehicle and the vehicle in front of it at time t; _amax and _amin represent the expected maximum acceleration and minimum deceleration, respectively; _s0 is the minimum safe stopping distance, and TH represents the reaction time of the following vehicle;

S314: Based on the above formula and using Newton's second law, the motion state of all vehicles in the virtual fleet can be further calculated as:

Where △t is the time step.

Furthermore, in S32, when the virtual fleet gradually approaches the traffic light, it will be constrained by the phase of the traffic light and stop and go, which can easily lead to the instability of the fleet and the decrease of traffic efficiency. In order to solve this phenomenon, a distributed collaborative control strategy is constructed, and the specific steps are as follows:

S321: Based on the established vehicle longitudinal dynamics model, the longitudinal control strategy of the connected automatic vehicle is constructed as follows:

in, Control input for connected autonomous vehicles. /> and/> is the control gain of the connected automatic vehicle. _{ψ jl,p} ,X _jl,p represent the weight and communication connection relationship between the position of the jth connected automatic vehicle and the position of the lth vehicle, ψ _jl,v ,X _jl,v represent the weight and communication connection relationship between the speed of the jth connected automatic vehicle and the speed of the lth vehicle, ψ _jl,a ,X _jl,a represent the weight and communication connection relationship between the acceleration of the jth connected automatic vehicle and the acceleration of the lth vehicle, and d _jl represents the desired vehicle distance between the jth connected automatic vehicle and the lth vehicle.

S322: Due to the uncontrollability of connected human driving, based on the vehicle dynamics model, the following strategy of connected human driving is established as follows:

In the formula, Represents the driver response parameter. Due to the uncontrollability of connected driving, Usually zero. /> λ _io,p respectively represent the weight and communication connection relationship between the position of the i-th connected person driving and the position of the o-th vehicle,/> λ _io,v respectively represent the weight and communication connection relationship between the speed of the ith connected person and the speed of the oth vehicle,/> λ _io,a respectively represent the weight and communication connection relationship between the acceleration of the ith connected human driver and the acceleration of the oth vehicle; d _io represents the expected distance between the ith connected human driver and the oth vehicle. In addition, since the connected human driver only has the communication function and is not controllable, it only follows the status of the multiple vehicles in front, so the above formula degenerates into:

Furthermore, at the physical layer, the driving status of the virtual fleet near the signal control area is explored, and how to obtain the status information of heterogeneous vehicles and the phase information of traffic lights through the information layer to adjust the status of the vehicles so that they can pass through the signal control area consistently and stably;

Furthermore, at the information layer, the communication topology of heterogeneous vehicles in the queue, the communication relationship between vehicles, and the communication relationship between vehicles and traffic lights are revealed.

Furthermore, the range of the connection area is defined as 80 meters, the connection point area is defined as 20 meters, the range of the near signal control area is defined as 300 meters, the communication range between the vehicle and the traffic light is defined as 400 meters, and the communication range between vehicles is positioned at 400 meters.

Beneficial effects:

The present invention utilizes communication technology, automatic driving technology and vehicle-road cooperative technology to obtain the status information of heterogeneous vehicles and the phase information of traffic lights as control input, and designs a linkage control method for the off-ramp and near-signal control area of a mixed traffic expressway. This method can improve the overall traffic efficiency of expressways and urban roads, and can provide a new perspective for solving the safety and congestion of new mixed traffic.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a mixed traffic scene in which an expressway off-ramp is connected to an urban road according to the present invention;

FIG2 is a schematic diagram of a method for controlling the linkage between an expressway off-ramp and a near-signal control area based on a cyber-physical system according to the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be described clearly and in detail below in conjunction with the accompanying drawings in the embodiments of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

Example 1

As shown in FIG. 1 and FIG. 2 , this embodiment provides a method for controlling the linkage between the off-ramp and the near-signal control area of a mixed traffic expressway, which includes the following steps:

Step S1: setting a mixed traffic scenario where the expressway off-ramp is connected to the near signal control area;

The expressway ramp is connected to the urban road to form a connection point. When the traffic volume is high, a conflict area will be formed. In addition, a traffic light is arranged in front of the urban road connection point, as shown in Figure 1. The intersection in Figure 1 indicates that vehicles entering the urban road from the expressway ramp are prone to conflict with vehicles on the urban road. There are m vehicles and n vehicles on the expressway ramp and the single lane of the urban road respectively, and the total number of vehicles is N = m + n, among which networked automatic vehicles and networked human drivers are mixed on the road. In such a scenario, the networked automatic vehicle and the networked human driver can obtain status information from each other through vehicle-to-vehicle communication. According to the obtained status information, the networked automatic vehicle can automatically adjust its own status, and the networked human driver follows the status of multiple vehicles in front of it. In addition, all heterogeneous vehicles can obtain information from traffic lights.

Step S2: Establishing a linear vehicle longitudinal dynamics model in combination with the vehicle's dynamic characteristics;

The nonlinear longitudinal dynamics of the vehicle can be expressed as follows:

Where p _i (t) and _vi (t) represent the position and speed of the i-th vehicle, is the mechanical efficiency of the transmission system. _ri represents the tire radius, _Ti (t) represents the actual driving/braking torque, _mi represents the vehicle mass, /> represents the aerodynamic drag coefficient, g represents the gravitational acceleration, _fi is the rolling resistance coefficient, θ( _pi (t)) represents the inclination angle of the road, _ζi represents the vehicle dynamics inertia delay, ^{and Tides} ₍ t) represents the desired driving/braking torque.

By using the linear feedback technique, the linear vehicle longitudinal dynamics model can be expressed as:

Where u _i (t) represents the control input of the vehicle;

When external factors are not considered, the linear dynamic model of the i-th vehicle degenerates into:

Where a _i (t) represents the acceleration of the i-th vehicle.

Step S3: In order to ensure the stability of the fleet, a linkage control method between the expressway off-ramp and the near-signal control area based on the cyber-physical system in a mixed traffic scenario is constructed. The method can be divided into the following steps:

Step S31: constructing a first-in-first-out collaborative control method;

When vehicles on the expressway ramp enter the urban road, in order to avoid long waiting time of heterogeneous vehicles in the link area and collision at the connection point, a first-in-first-out coordinated control method is established. The specific steps are as follows:

Step S311: At time t, heterogeneous vehicles in the link area obtain vehicle status information from each other through vehicle-to-vehicle communication;

Step S312: Using mapping technology, the status information of the connected automated vehicles and connected human vehicles on the expressway off-ramp is projected onto the city road, and the projected vehicles are sorted with the vehicles on the city road according to a first-in-first-out collaborative algorithm to form a virtual fleet;

Step S313: In order to ensure that all heterogeneous vehicles in the virtual fleet can maintain the desired vehicle spacing and speed, we use an intelligent driver model, which is specifically shown below:

Where _vi (t) is the speed of the i-th following vehicle at time t, _vmax is the maximum speed; △ _vi (t) and △ _si (t) represent the speed difference and distance between the i-th vehicle and the vehicle in front of it at time t; _amax and _amin represent the expected maximum acceleration and minimum deceleration, respectively; _s0 is the minimum safe stopping distance, and TH represents the reaction time of the following vehicle.

Step S314: According to the above formula, using Newton's second law, the motion state of all vehicles in the virtual fleet can be further calculated as:

Where △t is the time step.

Step S32: Establishing a distributed collaborative control method based on cyber-physical systems;

When the virtual fleet gradually approaches the traffic light, it will stop and start due to the phase constraints of the traffic light, which can easily lead to the instability of the fleet and reduce traffic efficiency. In order to solve this problem, a distributed collaborative control strategy is constructed. The specific steps are as follows:

Step S321: Based on the established vehicle longitudinal dynamics model, the longitudinal control strategy of the connected automatic vehicle is constructed as follows:

in, Control input for connected autonomous vehicles. /> and/> is the control gain of the connected automatic vehicle. _{ψ jl,p} ,X _jl,p represent the weight and communication connection relationship between the position of the jth connected automatic vehicle and the position of the lth vehicle, ψ _jl,v ,X _jl,v represent the weight and communication connection relationship between the speed of the jth connected automatic vehicle and the speed of the lth vehicle, ψ _jl,a ,X _jl,a represent the weight and communication connection relationship between the acceleration of the jth connected automatic vehicle and the acceleration of the lth vehicle, and d _jl represents the desired vehicle distance between the jth connected automatic vehicle and the lth vehicle.

S322: Due to the uncontrollability of connected human driving, based on the vehicle dynamics model, the following strategy of connected human driving is established as follows:

In the formula, Represents the driver response parameter. Due to the uncontrollability of connected driving, Usually zero. /> λ _io,p respectively represent the weight and communication connection relationship between the position of the i-th connected person driving and the position of the o-th vehicle,/> λ _io,v respectively represent the weight and communication connection relationship between the speed of the ith connected person and the speed of the oth vehicle,/> λ _io,a respectively represent the weight and communication connection relationship between the acceleration of the ith connected human driver and the acceleration of the oth vehicle; d _io represents the expected distance between the ith connected human driver and the oth vehicle. In addition, since the connected human driver only has the communication function and is not controllable, it only follows the status of the multiple vehicles in front, so the above formula degenerates into:

S323: Set the mixed fleet constraints as:

Since the current state of the vehicle depends on the constraint of the traffic light, the acceleration of the current vehicle constrained by the traffic light can be expressed as:

α _i (t) = θ ( v _i (t), △ v _{i, 0} (t), d _i (t), v _desired )

Among them, θ is the following model or control model function of the i-th vehicle, v _desired represents the desired speed, and d _i (t) represents the relative distance of the front vehicle or the distance from the stop line when the light is red, which can be expressed as:

The above formula indicates that if the phase of the traffic light is red, then d _i (t) is the distance from the current vehicle to the stop line, otherwise it is the relative distance between the current vehicle and the vehicle in front.

In order to allow the vehicles in the mixed virtual convoy to pass through the near signal control area without stopping, the arrival time of the vehicles in the mixed virtual convoy is estimated as

Where _ti represents the time to reach the traffic light at the desired speed in the green phase. _tdelay,i represents the delay time to avoid stopping under the traffic light constraint.

Figure 2 shows a schematic diagram of the linkage control method between the expressway off-ramp and the near-signal control area based on the cyber-physical system. In the physical layer of Figure 2, the driving status of the virtual fleet in the near-signal control area is explored, and how to obtain the status information of heterogeneous vehicles and the phase information of traffic lights through the information layer to adjust the status of the vehicles so that they can pass through the near-signal control area consistently and stably; in the information layer of Figure 2, a typical hybrid vehicle group communication topology is constructed to reveal the relationship between heterogeneous vehicles in the physical space and mapped to the information space.

In Figure 2, the range of the connection area is defined as 80 meters, the connection point area is defined as 20 meters, the range of the near signal control area is defined as 300 meters, the communication range between the vehicle and the traffic light is defined as 400 meters, and the communication range between vehicles is positioned at 400 meters.

The present invention utilizes communication technology, automatic driving technology and vehicle-road cooperative technology to obtain the status information of heterogeneous vehicles and the phase information of traffic lights as control input, and designs a linkage control method for the off-ramp and near-signal control area of a mixed traffic expressway. This method can improve the overall traffic efficiency of expressways and urban roads, and can provide a new perspective for solving the safety and congestion of new mixed traffic.

The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention.

Claims (5)

1. A linkage control method for a mixed traffic expressway down ramp and a near signal control area is characterized by comprising the following steps of: the method comprises the following steps:

s1: setting a mixed traffic scene of the connection of the expressway down ramp and the near signal control area;

s2: according to S1, combining dynamics characteristics of a vehicle, establishing a linear vehicle longitudinal dynamics model;

s3: according to S2, to ensure the stability of the motorcade, constructing a expressway off ramp and near signal control area linkage control method based on an information physical system in a mixed traffic scene;

The step S3 comprises the following steps:

S31: constructing a first-in first-out cooperative control method;

When the vehicles on the expressway off ramp enter the urban road, the S31 establishes a first-in first-out cooperative control method for avoiding the long waiting time of the heterogeneous vehicles in the link area and the collision at the joint point, and the specific steps are as follows:

s311: at the time t, heterogeneous vehicles in the link area mutually acquire the state information of the vehicles through vehicle-to-vehicle communication;

s312: the method comprises the steps of utilizing a mapping technology to project the state information of network-connected automatic vehicles and network-connected person driving on a expressway off ramp onto an urban road, and sequencing the projected vehicles and vehicles on the urban road according to a first-in first-out cooperative algorithm to form a virtual motorcade;

S313: to ensure that all heterogeneous vehicles in a virtual fleet are able to maintain a desired inter-vehicle distance and speed, an intelligent driver model is used, in the following specific form:

Wherein v _i (t) is the speed of the ith following vehicle at time t, and v _max is the maximum speed; deltav _i (t) and Deltas _i (t) represent the speed difference and spacing of the ith vehicle from its preceding vehicle at time t; a _max and a _min represent a desired maximum acceleration and minimum deceleration, respectively; s ₀ is the minimum parking safety distance, TH represents the reaction time of the following vehicle; a _i (t) represents the acceleration of the i-th vehicle;

S314: according to the formula in S313, using newton' S second law, the motion states of all vehicles in the virtual fleet are further calculated as:

Wherein Δt is the time step; p _i (t) represents the position of the i-th vehicle;

s32: establishing a distributed cooperative control method based on an information physical system;

s32 when virtual motorcade approaches the signal lamp gradually, the phenomenon of stopping when going and stopping when the constraint of signal lamp phase can appear, leads to the instability of motorcade and traffic efficiency to descend, in order to solve this phenomenon, constructs distributed cooperative control strategy, and the concrete step is:

S321: according to the established longitudinal dynamics model of the vehicle, the longitudinal control strategy of the networked automatic vehicle is constructed as follows:

Wherein, For control input of network-connected automatic vehicle,/>And/>The control gain of the network-connected automatic vehicle; the phi _jl,p,X_jl,p represents the weight and the communication connection relation between the position of the jth internet-connected automatic vehicle and the position of the first vehicle, the phi _jl,v,X_jl,v represents the weight and the communication connection relation between the speed of the jth internet-connected automatic vehicle and the speed of the first vehicle, and the phi _jl,a,X_jl,a represents the weight and the communication connection relation between the acceleration of the jth internet-connected automatic vehicle and the acceleration of the first vehicle; d _jl denotes a desired inter-vehicle distance between the jth networked vehicle and the first vehicle; ζ _i represents the vehicle dynamics inertia delay;

s322: because of uncontrollable driving of the internet-connected person, based on the vehicle dynamics model, the following strategy of driving of the internet-connected person is established as follows:

In the method, in the process of the invention, Representing a driver response parameter; because of uncontrollable driving of the internet-connected person,/>Typically zero; /(I)Lambda _io,p respectively represents weight and communication connection relation between driving position of ith Internet-connected person and parking position of the o-th vehicle,/>Lambda _io,v respectively represents the weight and the communication connection relation between the driving speed of the ith Internet-connected person and the speed of the o vehicle,/>Lambda _io,a respectively represents the weight and the communication connection relation between the driving acceleration of the ith internet-connected person and the acceleration of the o-th vehicle; d _io represents the desired inter-vehicle distance between the ith networked human drive vehicle and the o-th vehicle; the network-connected person drives the car only with a communication function, has no controllability and only follows the acquired states of a plurality of vehicles in front, so that the above formula is degraded into:

S323: the constraint conditions of the mixed motorcade are set as follows:

since the state of the current vehicle depends on the constraints of the signal, the acceleration of the current vehicle constrained by the signal can be expressed as:

α_i(t)＝θ(v_i(t),△v_i,0(t),d_i(t),v_desired)

Where θ is the following or control model function of the ith vehicle, v _desired represents the desired speed, d _i (t) represents the relative distance of the preceding vehicle or distance from the park line at red light, that can be expressed as:

the above indicates that d _i (t) is the distance from the current vehicle to the stop line if the phase of the signal lamp is red, otherwise is the relative distance between the current vehicle and the preceding vehicle;

In order to keep the vehicles in the hybrid virtual fleet from stopping through the near signal control zone, the arrival times of the vehicles in the hybrid virtual fleet are estimated as

Where t _i represents the time to reach the traffic light at the desired speed in the green phase and t _delay,i represents the delay time to avoid stopping under traffic light constraints.

2. The method for controlling the linkage of the mixed traffic expressway off ramp and the near signal control area according to claim 1, which is characterized in that: the S1 specifically comprises the following steps:

The expressway off ramp is connected with the urban road to form a connection point, and when the traffic flow is high, a conflict area is formed; a signal lamp is arranged in front of an urban road connecting point, m vehicles and N vehicles are respectively arranged on an expressway down ramp and an urban road single lane, the total number of the vehicles is N=m+n, and the network-connected automatic vehicles and the network-connected human driving vehicles are mixed on the road; under such a scene, the internet-connected automatic car and the internet-connected person driving car can mutually acquire state information through car-car communication, and the internet-connected automatic car can automatically regulate and control the state of the internet-connected automatic car according to the acquired state information, and the internet-connected person driving car follows the states of a plurality of cars in front of the internet-connected automatic car; wherein, all heterogeneous vehicles can acquire the information of signal lamp.

3. The method for controlling the linkage of the mixed traffic expressway off ramp and the near signal control area according to claim 2, which is characterized in that: the nonlinear longitudinal dynamics of the S2 vehicle are as follows:

Where p _i (t) and v _i (t) represent the position and speed of the ith vehicle, Is the mechanical efficiency of the transmission, r _i denotes the tire radius, T _i (T) denotes the actual driving/braking torque, m _i denotes the vehicle mass,/>Represents aerodynamic drag coefficient, g represents gravitational acceleration, f _i is rolling drag coefficient, θ (p _i (T)) represents inclination angle of road, ζ _i represents vehicle kinetic inertial retardation, and T _i ^des (T) represents desired driving/braking torque;

by using a linear feedback technique, a linear vehicle longitudinal dynamics model can be expressed as:

Where u _i (t) represents a control input to the vehicle;

When the external factors are not considered, the linear dynamics model of the ith vehicle is degenerated to:

where a _i (t) represents the acceleration of the i-th vehicle.

4. The method for controlling the linkage of the mixed traffic expressway off ramp and the near signal control area according to claim 3, wherein the method comprises the following steps:

In the physical layer, searching the running state of the virtual motorcade in the near signal control area, and how to acquire the state information of the heterogeneous vehicles and the phase information of the signal lamps through the information layer to adjust the states of the vehicles so that the vehicles can uniformly and stably pass through the near signal control area;

And in the information layer, the communication topological structure of heterogeneous vehicles in the queue, the communication relation among vehicles and the communication relation between the vehicles and the signal lamps are disclosed.

5. The method for controlling the linkage of the mixed traffic expressway off ramp and the near signal control area according to claim 4, wherein the method comprises the following steps:

The range of the engagement area is defined as 80 meters, the engagement point area is defined as 20 meters, the range of the near signal control area is defined as 300 meters, the communication range of the vehicle and the signal lamp is defined as 400 meters, and the communication range between vehicles is positioned as 400 meters.