CN102938201A - Electron hole microscopic traffic flow modeling method in density unsaturation state - Google Patents

Abstract

To solve the technical problem that an existing car-following model and actual traffic conditions are inconsistent so that the traffic flow statistics and intersection signal lamp control cannot be achieved, the invention provides an electron hole microscopic traffic flow modeling method in a density unsaturation state. According to the method, random variation of front car influences in a traffic flow speed model under the multi-lane conditions is considered according to four actual traffic conditions including normal queuing, traffic signal lamps stopping running cars, inserting of other cars caused by too large car following distances and car inserting of a current lane caused by too large car following distances of adjacent lanes, parameters such as equivalence speeds and traffic flow density of a macroscopic traffic flow model are introduced simultaneously, and car running lanes and influences of the car running lanes on the adjacent lanes are considered. The built novel microscopic traffic flow model is close to reality, and the traffic flow modeling technology in new roads design existing road running management and intersection signal lamp control is achieved.

Description

Electron hole microscopic traffic flow modeling method under the density unsaturated state

Technical field

The present invention relates to a kind of traffic flow model modeling method, particularly relate to the electron hole microscopic traffic flow modeling method under a kind of density unsaturated state.

Background technology

In order more reasonably to design new road, simulating, verifying to be carried out in existing road operational management and Signal on Highway Cross control program, usually need to set up traffic flow model, so that larger in the performance traffic capacity at equal means of transportation.

Communications and transportation is the significant problem that involves the interests of the state and the people, and the advanced degree of the up-to-dateness of traffic and transportation system and traffic administration is the important symbol of weighing a modernization of the country degree; In recent years, along with economic development, the quantity of the various vehicles increases greatly, facility, road, the traffic control system of a lot of countries have been difficult to satisfy this speed of development in the world, particularly inharmonious, the traffic dispersion system disappearance of not enough, the traffic control signal of big and medium-sized cities traffic infrastructure, vehicle scheduling and the confusion of management, all many-sided reasons such as friendship rule consciousness of traffic participant have caused urban transportation than jam, have caused again thus a series of socioeconomic problems such as traffic safety, environmental pollution.

Traffic problems are large system problems of a complexity, it has related to many-sided contents such as the synthetical collection of Comprehensive Control, transport information of urban traffic network and network transmission technology, traffic intelligent information fusion and treatment technology, traffic flow inductive technology, vehicle transport intelligent dispatching method, municipal intelligent traffic planing method, traffic safety detection, traffic environment overall evaluation system, and influence each other between above-mentioned each factor, mutually restrict, be the synthesis that correlativity is extremely strong, be difficult to portray this challenge with the unified form of describing; The problems such as the diversity of driving vehicle, inconsistency on the road so that people can't set up accurately traffic model with reference to physical law etc., can only adopt different approximate models to different traffic environments or application problem; At present traffic flow model is mainly adopted both macro and micro two large class descriptions, macroscopic traffic flow is to adopt hydromechanical viewpoint to set up the traffic stream characteristics model, and traffic flow is regarded as the compressible continuous fluid medium that is comprised of a large amount of vehicles; Traffic flow is regarded as the complicated self-driven particIe system that is comprised of a large amount of vehicles in the microcosmic traffic flow model, dynamic behavior from single unit vehicle, study the interaction between vehicle, and then obtain the character of whole Traffic flow systems, the average behavior of vehicle collective does not highlight.

Model is the microcosmic traffic flow model of a quasi-representative with speeding; When supposing that fleet travels in the bicycle road, do not allow that in the situation of overtaking other vehicles, rear car is followed the Vehicle Driving Cycle in the place ahead, therefore be called with speeding model; Distinguishing feature with the model of speeding is the solution that is easy to obtain its analytical form.With the speed v of model with vehicle of speeding, the equation that they satisfy is studied in relative velocity Δ v and space headway Δ x portrayal traffic flow; Can draw more easily stability condition and phase transformation scheduling theory characteristic with the model of speeding, system has vital role to development vehicle autonomous cruise; The numerical evaluation aspect, the simulation with speed model take time relevant with number of vehicles in research traffic system, with numerical method choose and the discrete steps Δ x of middle space x, time t relevant with Δ t; Domestic representative work is: 1, Wang Xiaoyuan, and meaningful will, Jia Hongfei, Meng Zhaowei is based on the vehicle follow gallop model investigation summary of safe spacing, Chang An University's journal (natural science edition), 2004, Vol.24 (6): pp51-54; 2, Zheng Maocai considers that the Following Car safe distance of front truck deceleration situation is analyzed Hunan transport science and techonologies, 2011, Vol.37 (2): pp190-193; 3, Han Xianglin, Li Xingli, Jiang Changyuan, the coupled map car-following model of vehicle comprehensive information before and after considering, traffic and transportation system engineering and information, 2009, Vol.9 (2): pp62-68; 4, Xiong Lieqiang, Wang Fu, Li Jie, the vehicle follow gallop model of vehicle speed relation before and after considering, Central China University of Science and Technology's journal (natural science edition), 2005, Vol.33 (9:pp87-90; 5, Peng Guanghan, the many cars of eyes front are followed the model stability analysis of speeding, the system engineering theory and practice, 2011, Vol.31(3): pp569-576; Also more to the traffic flow model result of study abroad, as document " Optimal velocity difference model for a car-following theory[J] .Physics Letters A.2011,375:3973 – 3977 " a kind of Optimal velocity difference model microscopic traffic flow is disclosed with the model of speeding:

$\frac{d^2{x}_n\left(t\right)}{{\mathrm{dt}}^2}=a\left\{V\right[{\mathrm{\Δx}}_n\left(t\right)]-\frac{{\mathrm{dx}}_n\left(t\right)}{\mathrm{dt}}\}+\mathrm{\λa}\frac{d{\mathrm{\Δx}}_n\left(t\right)}{\mathrm{dt}}+\mathrm{\γa}\left\{V\right[{\mathrm{\Δx}}_{n+1}\left(t\right)]-V[{\mathrm{\Δx}}_n\left(t\right)\left]\right\}$

This model be the people such as Peng Guanghan based on the basis of full speed degree differential mode type, consider that the new microscopic traffic flow of the poor formation of relative optimal speed is with speeding model; In the formula, x _n(t) be n car position of moment t,

The speed of n car of moment t, Δ x _n(t) be space headway between the continuous two cars, V[Δ x _n(t)] be n car optimal speed function, a is driver's sensitivity coefficient, and λ a is the response parameter of relative speed difference, and γ a is the poor response parameter of optimal speed; The impact of car before and after above-mentioned research work has been considered in the model of speeding, but satisfy assumed condition with the model of speeding because research work takes into full account actual road conditions, cause the highway section, intersection traffic flow model and the actual traffic situation that obtain inconsistent and can't use at traffic flow statistics and in the technology such as Signal on Highway Cross control.

Summary of the invention

Existing inconsistent and can't be in traffic flow statistics and the technical matters of controlling in Signal on Highway Cross with the actual traffic situation with the model of speeding in order to overcome, the invention provides the electron hole microscopic traffic flow modeling method under a kind of density unsaturated state, the method affects front vehicles in the traffic flow speed model according to normally travelling in the multilane situation, traffic lights stop driving vehicle, following distance causes too greatly other vehicle to insert, the adjacent lane following distance causes too greatly current track vehicle to insert the random variation of four kinds of actual traffic situations, introduced simultaneously the equivalent speed of macroscopic traffic flow, the parameters such as traffic flow density, considered the Vehicle Driving Cycle track and on the impact of adjacent lane, so that the new microcosmic traffic flow model of setting up, has solved the new road of design closer to reality, to Traffic Flow Modeling technical matters in existing road operational management and the Signal on Highway Cross control.

The technical solution adopted for the present invention to solve the technical problems is: the electron hole microscopic traffic flow modeling method under a kind of density unsaturated state is characterized in may further comprise the steps:

1, the electron hole microcosmic traffic flow model under the density unsaturated state is:

$\left\{\begin{array}{c}\frac{d^2{x}_n\left(t\right)}{{\mathrm{dt}}^2}=a\left\{V_e\right[{\mathrm{\Δx}}_n\left(t\right)]-\frac{{\mathrm{dx}}_n\left(t\right)}{\mathrm{dt}}\}+{\mathrm{\λ}}_a\frac{{\mathrm{d\Δx}}_n\left(t\right)}{\mathrm{dt}}+f\\ f=\left\{\begin{array}{cc}0& s=0\\ -A& s=0\\ {\mathrm{\γ}}_a\mathrm{sgn}[x_{n+1}\left(t\right)-x_n\left(t\right)-d_a]\left\{V\right[{\mathrm{\Δx}}_i\left(t\right)]-V[{\mathrm{\Δx}}_n\left(t\right)\left]\right\}& s=2\\ {\mathrm{\λ}}_{b0}\mathrm{sgn}\left(d_b\right)\left\{V\right[{\mathrm{\Δx}}_n\left(t\right)]-V[{\mathrm{\Δx}}_{n-1}\left(t\right)\left]\right\}+{\mathrm{\γ}}_{b1}[1-\mathrm{sgn}\left(d_b\right)]\left\{V\right[{\mathrm{\Δx}}_{n+1}\left(t\right)]-V[{\mathrm{\Δx}}_{n-1}\left(t\right)\left]\right\}& s=3\end{array}\right.\end{array}\right.$

In the formula, x _n(t) be n car position of moment t,

The speed of n car of moment t,

Be equivalent speed, v _fBe free travel speed, ρ is traffic flow density, ρ _JamSaturation flow density when blocking for appearance, l, m are the positive integer parameter, Δ x _n(t) be space headway between the continuous two cars, V[Δ x _n(t)] be n car optimal speed function, a is driver's sensitivity coefficient, λ _aIt is the response parameter of relative speed difference, s=0 during normal vehicle operation, n+1 the car in the place ahead s=1 when no thoroughfare by traffic lights by zebra stripes and n car, n+1 the car that n car followed the place ahead when travelling the space is arranged and by other track vehicle insert, s=2 when a n car has to regulate the speed, n car drives towards other track s=3 when jumping the queue, sgn is sign function $\mathrm{sgn}\left(x\right)=\left\{\begin{array}{cc}1& x>0\\ x& x\≤0\end{array}\right.,$ d _aFor the minimum that vehicle can insert is followed car space, γ _aBe that n car is to inserting the reaction coefficient of vehicle, V[Δ x _i(t)] for inserting the forward direction optimal speed function of vehicle, when n car drives towards other track but afterbody d when still causing the n-1 car at rear not cross in current track _b=1, d when the n-1 car that has driven towards other track, rear, current track fully when n car can be crossed _b=-1, γ _B0Be n-1 car n car driven towards other track but afterbody still at the reaction coefficient in current track, γ _B1Be that n-1 car driven towards other track fully, can accelerate to catch up with the reaction coefficient of following n+1 the car in the place ahead n car, A〉0 be the brake acceleration, in full the symbol implication is identical;

2, the parameters relationship in the model is: Δ t _k-Δ t _K-10, γ _Akγ _{A (k+1)}(k=1,2 ..., N);

3, will $\frac{{\mathrm{dx}}_n\left(t\right)}{\mathrm{dt}},\frac{{\mathrm{d\Δx}}_n\left(t\right)}{\mathrm{dt}},\frac{d^2{x}_n\left(t\right)}{{\mathrm{dt}}^2}$ Approximate expression is:

$\left\{\begin{array}{c}\frac{{\mathrm{dx}}_n\left(t\right)}{\mathrm{dt}}\≈\frac{x_n(t+T)-x_n(t-T)}{2T}\\ \frac{{\mathrm{d\Δx}}_n\left(t\right)}{\mathrm{dt}}\≈\frac{{\mathrm{\Δx}}_n(t+T)-{\mathrm{\Δx}}_n(t-T)}{2T}\\ \frac{d^2{x}_n\left(t\right)}{{\mathrm{dt}}^2}\≈\frac{8[x_n(t+T)-x_n(t-T)]-x_n(t+2T)+x_n(t-2T)}{12T}\end{array}\right.$

In the formula, T is the sampling period;

The electron hole microcosmic discrete traffic model that obtains under the density unsaturated state is:

x _n(t+2T)=(8+6a)[x _n(t+T)-x _n(t-T)]-12aTV _e[Δx _n(t)]-6λ _a[Δx _n(t+T)-Δx _n(t-T)]。

-12Tf+x _n(t-2T)

The invention has the beneficial effects as follows: owing in the multilane situation, front vehicles in the traffic flow speed model is affected according to normally travelling, traffic lights stop driving vehicle, following distance causes too greatly other vehicle to insert, the adjacent lane following distance causes too greatly current track vehicle to insert the random variation of four kinds of actual traffic situations, introduced simultaneously the equivalent speed of macroscopic traffic flow, the parameters such as traffic flow density, considered the Vehicle Driving Cycle track and on the impact of adjacent lane, so that the new microcosmic traffic flow model of setting up, has solved the new road of design closer to reality, to Traffic Flow Modeling technical matters in existing road operational management and the Signal on Highway Cross control.

Below in conjunction with embodiment the present invention is elaborated.

Embodiment

The concrete steps of the electron hole microscopic traffic flow modeling method under the density unsaturated state are as follows:

1, the electron hole microcosmic traffic flow model under the density unsaturated state is:

$\left\{\begin{array}{c}\frac{d^2{x}_n\left(t\right)}{{\mathrm{dt}}^2}=a\left\{V_e\right[{\mathrm{\Δx}}_n\left(t\right)]-\frac{{\mathrm{dx}}_n\left(t\right)}{\mathrm{dt}}\}+{\mathrm{\λ}}_a\frac{{\mathrm{d\Δx}}_n\left(t\right)}{\mathrm{dt}}+f\\ f=\left\{\begin{array}{cc}0& s=0\\ -A& s=0\\ {\mathrm{\γ}}_a\mathrm{sgn}[x_{n+1}\left(t\right)-x_n\left(t\right)-d_a]\left\{V\right[{\mathrm{\Δx}}_i\left(t\right)]-V[{\mathrm{\Δx}}_n\left(t\right)\left]\right\}& s=2\\ {\mathrm{\λ}}_{b0}\mathrm{sgn}\left(d_b\right)\left\{V\right[{\mathrm{\Δx}}_n\left(t\right)]-V[{\mathrm{\Δx}}_{n-1}\left(t\right)\left]\right\}+{\mathrm{\γ}}_{b1}[1-\mathrm{sgn}\left(d_b\right)]\left\{V\right[{\mathrm{\Δx}}_{n+1}\left(t\right)]-V[{\mathrm{\Δx}}_{n-1}\left(t\right)\left]\right\}& s=3\end{array}\right.\end{array}\right.$

In the formula, x _n(t) be n car position of moment t,

The speed of n car of moment t,

Be equivalent speed, v _fBe free travel speed, ρ is traffic flow density, ρ _JamSaturation flow density when blocking for appearance, l, m are the positive integer parameter, Δ x _n(t) be space headway between the continuous two cars, V[Δ x _n(t)] be n car optimal speed function, a is driver's sensitivity coefficient, λ _aIt is the response parameter of relative speed difference, s=0 during normal vehicle operation, n+1 the car in the place ahead s=1 when no thoroughfare by traffic lights by zebra stripes and n car, n+1 the car that n car followed the place ahead when travelling the space is arranged and by other track vehicle insert, s=2 when a n car has to regulate the speed, n car drives towards other track s=3 when jumping the queue, sgn is sign function $\mathrm{sgn}\left(x\right)=\left\{\begin{array}{cc}1& x>0\\ x& x\≤0\end{array}\right.,$ d _aFor the minimum that vehicle can insert is followed car space, γ _aBe that n car is to inserting the reaction coefficient of vehicle, V[Δ x _i(t)] for inserting the forward direction optimal speed function of vehicle, when n car drives towards other track but afterbody d when still causing the n-1 car at rear not cross in current track _b=1, d when the n-1 car that has driven towards other track, rear, current track fully when n car can be crossed _b=-1, γ _B0Be n-1 car n car driven towards other track but afterbody still at the reaction coefficient in current track, γ _B1Be that n-1 car driven towards other track fully, can accelerate to catch up with the reaction coefficient of following n+1 the car in the place ahead n car, A〉0 for the brake acceleration;

2, the parameters relationship in the model is: Δ t _k-Δ t _K-10, γ _Akγ _{A (k+1)}(k=1,2 ..., N);

3, will $\frac{{\mathrm{dx}}_n\left(t\right)}{\mathrm{dt}},\frac{{\mathrm{d\Δx}}_n\left(t\right)}{\mathrm{dt}},\frac{d^2{x}_n\left(t\right)}{{\mathrm{dt}}^2}$ Approximate expression is:

$\left\{\begin{array}{c}\frac{{\mathrm{dx}}_n\left(t\right)}{\mathrm{dt}}\≈\frac{x_n(t+T)-x_n(t-T)}{2T}\\ \frac{{\mathrm{d\Δx}}_n\left(t\right)}{\mathrm{dt}}\≈\frac{{\mathrm{\Δx}}_n(t+T)-{\mathrm{\Δx}}_n(t-T)}{2T}\\ \frac{d^2{x}_n\left(t\right)}{{\mathrm{dt}}^2}\≈\frac{8[x_n(t+T)-x_n(t-T)]-x_n(t+2T)+x_n(t-2T)}{12T}\end{array}\right.$

In the formula, T is the sampling period;

The electron hole microcosmic discrete traffic model that obtains under the density unsaturated state is:

x _n(t+2T)=(8+6a)[x _n(t+T)-x _n(t-T)]-12aTV _e[Δx _n(t)]-6λ _a[Δx _n(t+T)-Δx _n(t-T)]

-12Tf+x _n(t-2T)?。

Claims (1)

1. the electron hole microscopic traffic flow modeling method under the density unsaturated state is characterized in may further comprise the steps:

1) the electron hole microcosmic traffic flow model under the density unsaturated state is:

In the formula, x _n(t) be n car position of moment t,

The speed of n car of moment t,

Be equivalent speed, v _fBe free travel speed, ρ is traffic flow density, ρ _JamSaturation flow density when blocking for appearance, l, m are the positive integer parameter, Δ x _n(t) be space headway between the continuous two cars, V[Δ x _n(t)] be n car optimal speed function, a is driver's sensitivity coefficient, λ _aIt is the response parameter of relative speed difference, s=0 during normal vehicle operation, n+1 the car in the place ahead s=1 when no thoroughfare by traffic lights by zebra stripes and n car, n+1 the car that n car followed the place ahead when travelling the space is arranged and by other track vehicle insert, s=2 when a n car has to regulate the speed, n car drives towards other track s=3 when jumping the queue, sgn is sign function d _aFor the minimum that vehicle can insert is followed car space, γ _aBe that n car is to inserting the reaction coefficient of vehicle, V[Δ x _i(t)] for inserting the forward direction optimal speed function of vehicle, when n car drives towards other track but afterbody d when still causing the n-1 car at rear not cross in current track _b=1, d when the n-1 car that has driven towards other track, rear, current track fully when n car can be crossed _b=-1, γ _B0Be n-1 car n car driven towards other track but afterbody still at the reaction coefficient in current track, γ _B1Be that n-1 car driven towards other track fully, can accelerate to catch up with the reaction coefficient of following n+1 the car in the place ahead n car, A〉0 be the brake acceleration, in full the symbol implication is identical;

2) parameters relationship in the model is: Δ t _k-Δ t _K-10, γ _Akγ _{A (k+1)}(k=1,2 ..., N);

3) will

Approximate expression is:

In the formula, T is the sampling period;

The electron hole microcosmic discrete traffic model that obtains under the density unsaturated state is:

x _n(t+2T)=(8+6a)[x _n(t+T)-x _n(t-T)]-12aTV _e[Δx _n(t)]-6λ _a[Δx _n(t+T)-Δx _n(t-T)]

-12Tf+x _n(t-2T)?。