CN103267530A - Path planning method for best times of pipeline emergency repair - Google Patents

Abstract

The invention discloses a path planning method for best times of pipeline emergency repair. The path planning method comprises: comprehensively considering the effect such factors on travel time as weather, traffic jam condition, commercial activity, and the like, replacing a virtual path length with an actual road length, calculating the weight of each road segment according to factors affecting the travel time, obtaining the travel time of a vehicle passing the road segment through a Dijkstra algorithm optimized by a heuristic function and a vehicle speed determined by a speed-flow rate model, and obtaining the optimal emergency repair with best times as selection target.

Description

The paths planning method of a kind of pipe first-aid shortest time

Technical field

The invention belongs to the method for quickest routing planning in pipe first-aid field.

Background technology

Because the scope that relates to of long distance oil pipeline is big, with a varied topography, the existence of unfavorable factors such as humanity, the social environment through the zone be varied, when pipeline occur running, emit, leak, droplet phenomenon and during burst accident such as the pilferage of punching, the pipe first-aid personnel can not arrive the site of an accident quickly and accurately, and this certainly will cause the bigger economic loss of pipeline enterprise and to the more havoc of physical environment.The shortest select target that becomes pipeline enterprise repairing optimal path of repairing journey time, however according to present achievement in research, the researcher only link length and the speed of a motor vehicle as the foundation that makes up searching algorithm, the path that searches is often bigger with actual difference.For example, in the vehicle driving process, undesirable elements such as inclement weather, incommutation peak, fairground and large scale business district can increase considerably the journey time in highway section, even can reach 17%～35% of whole Link Travel Time.Therefore, in the route searching process, we must take all factors into consideration the influence of these undesirable elements.

The basic thought of dijkstra's algorithm is to produce shortest path by the order that the road weight increases progressively.This thought is more effective to the solving the shortest path of single node to many nodes or many nodes to single node, but to the shortest route problem between single node the most widely in the practical application, because need too many unnecessary node and the sideline of traversal, efficient is lower, time complexity is higher.So the present invention utilizes, and the shortest geometrical principle of straight line designs heuristic function as heuristic information between 2, bootstrap algorithm is along the route searching that is hopeful most to arrive fast the order node, and then dwindles the hunting zone, reduces the number of search node, effectively reduce time complexity, accelerate search speed.

Summary of the invention

The problem that will solve of the present invention is to consider the influence of factors such as weather, congested traffic condition and business activity to journey time, utilize the path virtual length to replace the thought of road physical length, dijkstra's algorithm in conjunction with heuristic function optimization, solve time shortest path that rule of thumb in the past obtains and actual inconsistent problem, greatly reduced the economic loss that pipe leakage causes enterprise and pollution that physical environment is caused.

Embodiment

For factors such as weather conditions, congested traffic condition and business activities, a weight that can be used as road joins in the tables of data of highway section correspondence, and the method by Shortest Path Analysis obtains the route programming result in conjunction with dynamic environment information.

In the time shortest path first, still road is abstracted into oriented weighted graph G=＜N, E 〉, nodal set is N, the set of directed edge is E between node, node i, j ∈ N, the line between the two is designated as k _{I, j}

Vehicle is through k _{I, j}Journey time comprises three parts: the vehicle travel time

Car park payment time and traffic delays time

Road net situation according to present China, it is less that charging section accounts for toatl proportion, and the chargeable time model is comparatively complicated, many factors are difficult to quantize, must demarcate separately and could use each charge station, and present achievement in research does not also satisfy the needs that engineering is used, and awaits further further investigation, so the present invention does not consider the Car park payment time.

According to present achievement in research, the quantitative estimation of traffic delays time is theoretical and immature, and many factors are difficult to quantize, and can not satisfy the needs that engineering is used.By t=L/v as can be known, under the certain situation of speed, time and path are directly proportional, that is, and and t ∞ L.Therefore can regard the inhibition of the unfavorable factor that influences the traffic delays time as prolonged the path length, the factor that is difficult to quantize is converted into k _{I, j}Virtual length L ' _{I, j}, and then obtain the traffic delays time

This paper utilizes the weight calculation formula to try to achieve the power m of corresponding factor ^k _{I, j}, at k _{I, j}Under the known situation of physical length, the build path virtual length:

$L_{i,j}^{\′}=\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{m}_{i,j}^k*L_{i,j}$

Therefore by highway section k _{I, j}Journey time can be expressed as:

$t_{i,j}=t_{i,j}^1+t_{i,j}^2=\frac{L_{i,j}}{v_{i,j}}+\frac{L_{i,j}^{\′}}{v_{i,j}}=\frac{L_{i,j}+L_{i,j}^{\′}}{v_{i,j}}=\frac{(1+\underset{k=1}{\overset{n}{\mathrm{\Σ}}}{m}_{i,j}^k)*L_{i,j}}{v_{i,.j}}$

In the formula:

The vehicle travel time;

The traffic delays time;

L _{I, j}: highway section k _{I, j}Physical length;

Highway section k _{I, j}The weight of k variable correspondence;

v _{I, j}: vehicle is at highway section k _{I, j}Average speeds.

By above-mentioned analysis, only need to determine v _{I, j},

L _{I, j}Value just can calculate vehicle through k _{I, j}The Link Travel Time of Shi Suoxu, and then obtain source node p to the time shortest path between the destination node q by the dijkstra's algorithm of optimizing.

Shortest time between two nodes can be expressed as:

$\min T_{p,q}=\min \underset{i,j}{\mathrm{\Σ}}{t}_{i,j}$ $\∀p,q,i,j\∈N$

The traffic delays time is mainly caused by factors such as inclement weather, incommutation peak, fairground and large scale business districts.According to virtual route length formula (1) as can be known, at L _{I, j}Under the known situation, determine the weight of each factor correspondence

Just can obtain k _{I, j}Virtual length, and then definite t _{I, j}Value as search condition.

According to the virtual route length formula as can be known, under known situation, determine the weight of each factor correspondence with regard to available virtual length, and then the value of determining.The obtaining value method step is as follows.

The path virtual length value of step 1 weather conditions correspondence;

Inclement weathers such as rain, snow, hail influence driver's safe driving, reduce road passage capability, must consider that therefore weather conditions are to the influence of road.

Attachment coefficient refers to tire in the adhesive ability size on different road surfaces, and is relevant with weather conditions, the speed of a motor vehicle, carload etc.The more easy driving in the road surface that attachment coefficient is more high, vehicle, security is more high.Therefore the size of the description road passage capability that road-adhesion coefficient can be quantitative, and then the weight of definite weather condition correspondence.Road peak adhesion coefficient can be expressed as:

${\mathrm{\μ}}_{\mathrm{xp}}=0.92\×{0.1304}^r+0.002e^r(64-\mathrm{\υ})-0.0426\sqrt{u}$

γ: characterize the enclosing characteristic factor of pavement behavior, see Table 1; V: the speed of a motor vehicle, km/h, u: wheel loading coefficient, u=F _x/ F _s, F _x: the actual load-carrying of tire, F _s: the demarcation load-carrying of tire.

The characterization factor on the common road surface of table 1

According to above-mentioned analysis, vehicle is under zero the situation in empty wagons, dried asphalt road and speed, road peak adhesion coefficient maximum, and weather is to the minimum that influences of traffic delays time.Along with the deterioration of weather conditions, weather increases gradually to the influence of traffic delays time, so we can be γ=0, v=0, F _x=0 o'clock peak adhesion coefficient μ ₀As scalar quantity.μ by empty wagons correspondence under more various weather, pavement behavior and the speed _XpWith μ ₀μ ₀Size obtain the weight of inclement weather correspondence $m_{i,j}^1={\mathrm{\μ}}_{\mathrm{xp}}/{\mathrm{\μ}}_0.$

The path virtual length value of step 2 road congested conditions correspondence;

The incommutation summit causes blocking up of a large amount of vehicles, increases the traffic delays time, therefore must consider the influence to traffic on and off duty.And in non-incommutation peak time, vehicle often can pass through smoothly, so we can be by peak period more on and off duty and the non-peak period on and off duty percentage weight of definite incommutation peak correspondence recently of the average shared whole day road traffic of volume of traffic total amount per hour

According to China resident's life, the condition of production, four incommutation peaks can appear within one day, and be respectively the journey that in morning and afternoon, the backhaul in noon and evening, lasting timing definition is: t ₀₁, t ₀₂, t ₀₃, t ₀₄, the number percent that this section period vehicular traffic amount accounts for whole day is n ₀₁, n ₀₂, n ₀₃, n ₀₄In the practical application, concrete every section road time corresponding and number percent must could finally be determined through the lot of data statistics.

The number percent of the average shared whole day road traffic of volume of traffic total amount per hour in the incommutation section in rush hour:

N ₀₁＝(n ₀₁+n ₀₂+n ₀₃+n ₀₄)÷(t ₀₁+t ₀₂+t ₀₃+t ₀₄)

The number percent of the average shared whole day road traffic of volume of traffic total amount per hour in the non-incommutation section in rush hour:

N ₀₂＝[(1-n ₀₁)+(1-n ₀₂)+(1-n ₀₃)+(1-n ₀₄)]÷(24-t ₀₁-t ₀₂-t ₀₃-t ₀₄)

The weight of peak on and off duty correspondence then

The path virtual length value of step 3 business activity correspondence;

Fairground and large scale business district to the influence of road have the time, scope is fixed, characteristics such as influence power is big, but according to existing achievement in research, they do not have more perfect mathematical model to quantize to calculate to the influence of Link Travel Time and can only rely on people's experience to judge and estimate.1～9 ratio scaling law that utilizes Satty to propose has provided under the different categories of roads with the characteristic root method With Value sees Table 2.

The weight coefficient of table 2 fairground and large scale business district correspondence

Road quality classification	At a high speed	One-level	Secondary	Three grades	Level Four
						The fairground	0	0	6.3	7.2	7.5
The large scale business district	0	0	6.7	7.5	8.3

So far, provided method and the computing formula of determining the weight of certain section road.During practical application, all kinds of factors that are difficult to quantize, influence journey time have been taken all factors into consideration, calculate the weight of every section road according to the factor that influences journey time, in conjunction with the definite speed of a motor vehicle of speed-flow model, just can obtain vehicle through the journey time in certain highway section, by the dijkstra's algorithm of optimizing, can obtain the shortest with the time is the optimum repairing path of select target.

Claims (2)

1. the present invention proposes a kind of paths planning method for the pipe first-aid shortest time, it is characterized in that: utilize the path virtual length to replace the thought of road physical length, in conjunction with the dijkstra's algorithm that heuristic function is optimized, the realization shortest time is rushed to repair the search in path.

2. method for quickest routing planning according to claim 1, it is characterized in that: taken all factors into consideration factors such as weather conditions, congested traffic condition and business activity to rushing to repair the influence of time, weather conditions, a congested traffic condition and business activity weight as road is joined in the tables of data of highway section correspondence, and the method by Shortest Path Analysis obtains the route programming result in conjunction with dynamic environment information.