CN100395789C - Blocking inhibiting method for city road traffic system - Google Patents

Abstract

The present invention discloses a blockage inhibiting method for city road traffic systems. A blockage signal control technique is provided, a travelling speed of an existing vehicle and a travelling speed signal of a front vehicle measured by a vehicle velometer are transferred to a monolithic computer, and the monolithic computer determines a feedback coefficient according to a designed feedback control signal and a nonblocking condition, and calculates accelerating or decelerating prompting information which is displayed on a display device. When drivers see the prompting information, the drivers can properly adjust the travelling speed according to the prompt information, so the reaction sensitivity of the drivers is improved, and the traffic blockage caused by that the drivers do not respond the situation of front vehicles in time is avoided. The control technique has the advantages of simple structure, low cost and easy realization. When the method of the control technique is used, the formation of a blocked traffic flow is inhibited, the driving safety and the driving comfort are improved, and the traffic capacity of roads are fully utilized.

Description

A kind of blocking inhibiting method of City road traffic system

Technical field

The present invention relates to a kind of blocking inhibiting method of City road traffic system, more particularly relate to a kind of block signal control technology of City road traffic system, belong to traffic signals control technology field.

Background technology

Along with The development in society and economy, urban automobile quantity increases sharply, thereby causes urban traffic blocking or obstructing problem to increasingly sharpen, and seriously hampers the process of urban modernization.For fundamentally solving the problem of blocking up of urban transportation, since the sixties in 20th century, developed country has carried out urban traffic control research, its role is to: by clocklike controlling and use traffic signals, make vehicle sail out of the conflict area orderlyly.But the urban road transportation control problem is quite complicated, many achievements all very imperfection, especially people how to inquire into the traffic flow of blocking up on the road seldom according to the formation mechanism of traffic jam, reasonably dredge, to relax or the prevention traffic jam.

At present about in this respect research, Konishi etc. is arranged, and (Phys.Rev.E 60,4000-4007,1999) based on the feedback delay technology blocking inhibiting method has been proposed, mainly be to utilize the output signal of speed inhibit signal and auto model observer to design control signal, solved the traffic jam problem of road traffic system basically.But this method has following weak point:

1. control signal design process complexity, the parameter that relates to are many, and the design of control signal is carried out the observer design to auto model earlier, and then the acquisition speed inhibit signal;

2. parameter can only be designed to fixed value, and often there is certain fluctuation range in parameter value in the reality, so this is to be difficult to realize under actual conditions;

3. the design of control signal also needs bigger memory headroom, and in order to the memory historical data, thereby its expense is comparatively expensive.

Therefore, explore be easier to realize, new blocking inhibiting method that investment cost is lower, will become the development trend that City road traffic system blocks control technology.The blocking inhibiting method that purpose of the present invention just provides a kind of simplicity of design, is easy to realize enables to directly apply to City road traffic system, alleviates traffic jam issue, improves the service efficiency of urban road.

Summary of the invention

In order to have the signal complexity in the blocking inhibiting method that overcomes Konishi etc., to realize the deficiency of aspect such as difficult, with high costs, the form that the invention provides is simple, be easy to realize, the blocking inhibiting method of a kind of City road traffic system with low cost, dredge the traffic flow of blocking up, improve the security and the smoothness of vehicle '.

The present invention is achieved through the following technical solutions:

On the vehicle that travels control device is installed, it mainly comprises vehicle-mounted velometer, single-chip microcomputer and display device.Adjacent front truck vehicle speed signal and Ben Che vehicle speed signal that vehicle-mounted velometer records are passed to single-chip microcomputer, determine feedback factor by single-chip microcomputer according to the feedback control signal and the clog-free condition of design, calculate the acceleration and deceleration information, be shown on the display device, after the driver sees information, information is adjusted the travel speed of vehicle rightly in view of the above, thereby improves driver's reaction susceptibility.

The mathematical model of the vehicular traffic system of vehicle before controlling is described as:

A. guide car (first car on the road driving direction)

x ₁(n+1)＝v ₀·T+x ₁(n)

Wherein, x ₁(n)＞0 be guided vehicle in constantly position of nT (unit: rice), v ₀The＞0th, (in general, can be considered constant, unit: meter per second), T is a sampling time interval (unit: second) to the speed of guided vehicle.

B. with speeding vehicle (following the vehicle of first car on the road driving direction)

x _i(n+1)＝v _i(n)T+x _i(n)，(i＝2～N)

$v_i(n+1)={\mathrm{\α}}_i[V_i^{\mathrm{op}}\left(d_i\left(n\right)\right)-v_i\left(n\right)]T+v_i\left(n\right)$

(1)

d _i(n+1)＝x _i-1(n+1)-x _i(n+1)＝v _i-1(n)·T-v _i(n)·T+d _i(n)

Wherein, x _i(n)＞0 be vehicle i in constantly position of nT (unit: rice), v _i(n) be that (unit: meter per second), N is a vehicle fleet on the road to vehicle i, α in nT speed constantly _iBe sensitivity coefficient (unit: second ^-1), V ^Op() is the optimal speed function, d _i(n) be front truck i-1 and the space headway of car i thereafter.The form of optimal speed function is:

$V_i^{\mathrm{opt}}\left(d_i\left(n\right)\right)=\frac{v_i^{\max }}{2}[1+{\stackrel{\‾}{H}}_{\mathrm{sat}}\left(2\frac{d_i\left(n\right)-{\mathrm{\η}}_i}{{\mathrm{\ζ}}_i}\right)]$

H _Sat() is

${\stackrel{\&OverBar;}{H}}_{\mathrm{sat}}\left(\mathrm{\&rho;}\right)=\left\{\begin{array}{ccc}+1,& \mathrm{if}& +1<\mathrm{\&rho;}\\ \mathrm{\&rho;},& \mathrm{if}& -1\&le;\mathrm{\&rho;}\&le;+1\\ -1,& \mathrm{if}& \mathrm{\&rho;}<-1\end{array}\right.$

$v_i^{\max }>0$ Be the maximal rate of vehicle i, η _iThe＞0th, suitable space headway, ζ _iThe＞0th, the adjustment parameter of the expection speed of a motor vehicle.

When the congestion feedback control signal is introduced the vehicular traffic system, implement FEEDBACK CONTROL to following the vehicle of speeding, its feedback control signal is to be realized by following formula:

u _i(n)＝k _i(v _i-1(n)-v _i(n)) (2)

Wherein, u _i(n) be the feedback control signal of vehicle i, k _iBe feedback control coefficient (scalable), v _i(n) be the nT speed (unit: meter per second) of vehicle i constantly.The introducing of this control signal will make the vehicle driver in the process of moving adjacent front truck behavior in time be made a response, and to avoid acceleration and deceleration continually or inappropriate driving behavior, the formation of pre-anti-blocking improves the security and the comfortableness of driving.

Vehicular system model after the adding feedback control signal correspondingly is adjusted into:

$v_i(n+1)={\mathrm{\&alpha;}}_i[V_i^{\mathrm{opt}}\left(d_i\left(n\right)\right)-v_i\left(n\right))]T+v_i\left(n\right)+u_i\left(n\right)$

The obstruction that the present invention can solve a class vehicular traffic system widely suppresses problem, and technical key wherein of the present invention is: the traffic feedback of vehicle is blocked control signal, and technical foundation is: the choke free feedback factor condition of road traffic system.

Determining of the feedback factor of feedback control signal:

Feedback factor k _iCan regulate, so that control system satisfies clog-free condition.Can draw under the different vehicle parameter feedback factor k through deriving _iSpan:

If a) α _iT-2＜0 and α _ir _iT ²-α _iT＜0, promptly vehicle belongs to the type that reaction sensitivity is low and maximal rate is lower, wherein α _iBe sensitivity coefficient (unit: second ^-1), $r_i=\frac{v_i^{\max }}{{\mathrm{\&zeta;}}_i},$ $v_i^{\max }>0$ Be the maximal rate of vehicle i, so $1-{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2<k_i\&le;\frac{2-{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2}{2};$ 0＜α else if _ir _iT ²＜2 and (α _iT-2) (r _iT-1)＞0, promptly vehicle belongs to the low and low-down type of maximal rate of reaction sensitivity, so

$\max \{{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T,\frac{1}{2}(2r_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T)\}<k_i\&le;1-{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2;$

B) if 2＜α _ir _iT ²＜4 and 4-α _iT-2r _iT＞0, promptly vehicle belongs to reaction sensitivity height and the lower type of maximal rate, or the type that reaction sensitivity is low and maximal rate is higher, so

$\max \{{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T,\frac{1}{2}(2r_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T)\}<k_i<\frac{4-2{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2}{2};$

C) if α _ir _iT ²=2 and (α _iT-2) (r _iT-1)＞0, promptly vehicle belongs to the type that reaction sensitivity is moderate and maximal rate is moderate, so $\max \{{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T,\frac{1}{2}(2r_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T)\}<k_i<3-{\mathrm{\&alpha;}}_{i}T;$

D) if α _iT=2 and 0＜α _ir _iT ²＜2, promptly vehicle belongs to the type that reaction sensitivity is moderate and maximal rate is lower, so $1-{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2<k_i<\frac{4-{2\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2}{2}.$

Realize that method of the present invention may further comprise the steps:

(1), comprises sensitivity parameter α according to the vehicle set initial parameter _i, maximum speed parameter v _Max, the space headway η of expection _i, the adjustment parameter ζ of the expection speed of a motor vehicle _iWith data sampling time interval T;

(2) determine the feedback factor k of feedback control signal according to the clog-free feedback condition of road traffic system _i, be stored in the single-chip microcomputer;

(3) velocity information that records of vehicle-mounted velometer is sent in the single-chip microcomputer, determines feedback factor by single-chip microcomputer according to the feedback control signal formula [formula (2)] and the clog-free condition of design, calculates the acceleration and deceleration information;

(4) acceleration and deceleration information is shown on the display device, the driver will travel to change to adjacent front truck in time and make a response with reference to this information, thereby improve driver's the reaction sensitivity and the security of driving.

The present invention compared with prior art, its advantage and good effect are:

A) the feedback signal designing institute needs the rate signal of vehicle, can obtain by vehicle-mounted velometer of this vehicle or intelligent transportation system, and is comparatively convenient;

B) design of feedback control signal only need be determined a parameter-feedback factor k _iValue and can changing in the larger context, its form is very simple, realizes easily;

C) design of feedback control signal only needs the velocity information of this car and adjacent front truck, and required internal memory and calculated amount are less, and the design concept of control is simple, and hardware is few, expense is low, and applicable scope is wide;

D) in the design process of control signal, do not have the hypothesis of special circumstances, so this control method do not rely on the concrete parameter of auto model, can handle the obstructing problem under the multiple situation, as bottleneck, traffic hazard or disturbance cause; Can be common to the situation of single track and multiple tracks.

Description of drawings

Fig. 1 suppresses the control system process flow diagram for the present invention blocks;

Fig. 2 suppresses the control system block scheme for the present invention blocks;

Fig. 3 blocks the inhibition technical schematic diagram for the present invention;

Fig. 4 (a) is no control action space headway of all vehicles on the road in the time of following 2000 seconds;

Fig. 4 (b) blocks control action space headway of all vehicles on the road in the time of following 2000 seconds for the present invention.

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is further described:

As shown in Figure 1, blocking inhibiting method performing step of the present invention is:

Step 1. comprises sensitivity parameter α according to the vehicle set initial parameter _i, maximum speed parameter v _Max, the space headway η of expection _i, the adjustment parameter ζ of the expection speed of a motor vehicle _iWith data sampling time interval T;

Step 2. is determined the feedback factor k of feedback control signal according to the clog-free feedback condition of road traffic system _i, be stored in the single-chip microcomputer;

The velocity information that the vehicle-mounted velometer of step 3. records is sent in the single-chip microcomputer, determines feedback factor by single-chip microcomputer according to the feedback control signal formula [formula (2)] and the clog-free condition of design, calculates the acceleration and deceleration information;

Step 4. is shown in acceleration and deceleration information on the display device, and the driver will travel to change to adjacent front truck in time and make a response with reference to this information, thereby improve driver's the reaction sensitivity and the security of driving.

As shown in Figure 2, all vehicles have constituted a vehicle control system on the road, and it is relevant that each control with the vehicle of speeding only is adjacent front truck, thereby this control system can be decomposed into N vehicle control subsystem again.

As shown in Figure 3, control device is installed on driving vehicle, is comprised vehicle-mounted velometer, single-chip microcomputer and numeric display unit.In control procedure, front truck (vehicle i-1) that vehicle-mounted velometer is recorded and the vehicle speed signal of this car (vehicle i) are sent in the single-chip microcomputer, by feedback control signal and the feedback factor k of single-chip microcomputer according to design _iCalculate the acceleration and deceleration information, and be shown on the numeric display unit, after the driver of vehicle i sees information, can be in view of the above information adjust the travel speed of vehicle rightly, thereby avoid in time the front vehicles situation being made a response and the traffic congestion that causes.

Simulated experiment:

The control technology of blocking inhibiting method of the present invention is applied to the road that there are traffic bottlenecks in the bicycle road, simulates the variation of its traffic, primary study should block control technology to the space headway of wagon flow on the road and the influence of the magnitude of traffic flow, as shown in Figure 4.Suppose long 2000 meters of road, have traffic bottlenecks (long 400 meters) at 1000 meters, vehicle obviously slows down to guarantee safety herein, and this will make its upstream vehicle form and block up.

The result of simulated experiment shows: when not implementing FEEDBACK CONTROL, shown in Fig. 4 (a), large-scale fluctuation (from 11 meters to 45 meters) has appearred in bottleneck upstream vehicle headstock spacing, the traffic congestion phenomenon occurred, and there is bigger potential safety hazard in only about 11 meters of minimum space headway.And under the effect of having implemented FEEDBACK CONTROL, shown in Fig. 4 (b), the vehicle headstock spacing of bottleneck upstream is comparatively even, maintains substantially about 35 meters, does not form significantly fluctuation, and vehicle is uniform sequential to travel, and choking phenomenon promptly do not occur.

In the simulated experiment process, be provided with a virtual detector in somewhere, bottleneck downstream, detect the vehicle number that passes through in the unit interval, i.e. the magnitude of traffic flow.The magnitude of traffic flow was not 2300/hour when data presentation was implemented FEEDBACK CONTROL; And after the adding FEEDBACK CONTROL, the magnitude of traffic flow increases to 2621/hour, has increased by 1 14.Obviously, the enforcement that this blocks control technology makes the driver can understand the driving condition of adjacent front truck all sidedly, and the driver in time adjusts its travel speed according to this information, thereby has avoided the formation of traffic jam, and has improved the security and the smoothness of driving.

Claims (2)

1. the blocking inhibiting method of a City road traffic system is characterized in that:

On the vehicle that travels, control device is installed, it comprises vehicle-mounted velometer, single-chip microcomputer and display device, adjacent front truck vehicle speed signal and Ben Che vehicle speed signal that vehicle-mounted velometer is recorded are sent to single-chip microcomputer, single-chip microcomputer is determined feedback factor according to clog-free condition, and, calculate the acceleration and deceleration information according to determined feedback factor and feedback control signal, be shown on the display device, after the driver saw information, information was adjusted the travel speed of vehicle in view of the above;

The setting of described feedback control signal is only relevant with adjacent preceding vehicle speed, is realized by following formula:

u _i(n)＝k _i(v _i-1(n)-v _i(n))

Wherein, u _i(n) be the feedback control signal of vehicle i, k _iBe feedback control coefficient, v _i(n) be the nT speed of vehicle i constantly, its unit is a meter per second, and T is a sampling time interval, and its unit is second;

Described clog-free condition is used for determining the feedback factor k of described feedback control signal _iValue, promptly determine by following formula:

(a) if α _iT-2＜0 and α _ir _iT ²-α _iT＜0, promptly vehicle belongs to the type that reaction sensitivity is low and maximal rate is lower, so

$1-{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2<k_i\&le;\frac{2-{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2}{2};$

0＜α else if _ir _iT ²＜2 and (α _iT-2) (r _iT-1)＞0, promptly vehicle belongs to the low and low-down type of maximal rate of reaction sensitivity, so

$\max \{{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T,\frac{1}{2}(2r_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T)\}<k_i\&le;1-{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2;$

(b) if 2＜α _ir _iT ²＜4 and 4-α _iT-2r _iT＞0, promptly vehicle belong to the reaction sensitivity height and maximal rate lower, or the type that reaction sensitivity is low and maximal rate is higher, so

$\max \{{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T,\frac{1}{2}(2r_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T)\}<k_i<\frac{4-2{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2}{2};$

(c) if α _ir _iT ²=2 and (α _iT-2) (r _iT-1)＞0, promptly vehicle belongs to the type that reaction sensitivity is moderate and maximal rate is moderate, so

$\max \{{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T,\frac{1}{2}(2r_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2-{\mathrm{\&alpha;}}_{i}T)\}<k_i<3-{\mathrm{\&alpha;}}_{i}T;$

(d) if α _iT=2 and 0＜α _ir _iT ²＜2, promptly vehicle belongs to the type that reaction sensitivity is moderate and maximal rate is lower, so $1-{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2<k_i<\frac{4-2{\mathrm{\&alpha;}}_{i}T+{\mathrm{\&alpha;}}_i{r}_i{T}^2}{2};$

Wherein, α _iBe the sensitivity coefficient of vehicle, unit: second ^-1, $v_i^{\max }>0$ Be the maximal rate of vehicle i, ζ _iThe adjustment parameter of＞0 expection speed of a motor vehicle, $r_i=\frac{v_i^{\max }}{{\mathrm{\&zeta;}}_i}$ Adjust the ratio of parameter for the maximal rate and the expection speed of a motor vehicle.

2. blocking inhibiting method according to claim 1 is characterized in that:

This method is further comprising the steps of:

(1) according to the vehicle set initial parameter: comprise sensitivity parameter α _i, maximum speed parameter v _Max, the space headway η of expection _i, the expection speed of a motor vehicle is adjusted parameter ζ _iWith data sampling time interval T;

(2), determine the feedback factor k of described feedback control signal according to the clog-free feedback condition of road traffic system _i, and be stored in the single-chip microcomputer;

(3) velocity information that records of vehicle-mounted velometer is sent to single-chip microcomputer, and single-chip microcomputer calculates the acceleration and deceleration information according to the realization formula of determined feedback factor and described feedback control signal;

(4) acceleration and deceleration information is shown on the display device, the driver will travel to change to front truck in time and make a response with reference to this information, thereby improve driver's the reaction sensitivity and the security of driving.

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