CN105448082A - BRT (bus rapid transit) combined dispatching method capable of achieving variable bus departure intervals - Google Patents

Abstract

The invention belongs to the technical field of public transport dispatching and optimization, and especially relates to a BRT (bus rapid transit) combined dispatching method capable of achieving variable bus departure intervals. The method comprises the steps: determining the total number of stops and the total number of bus departure times, and obtaining the driving time of vehicles among stops, passenger flow information, the get-on time of passengers, the get-off time of passengers, and stopping time of vehicles; obtaining the number of get-on and get-off passengers at each stop, so as to determine the type of the stop as a BRT stop or common stop; taking a combination mode and a departure interval as decision variables; building a bus dispatching model, calculating the stop time and the number of get-on and get-off passengers of each vehicle at each stop, solving a target function expression, i.e., calculating the mean waiting time of passengers, the mean on-bus time of passengers, and the mean seating capacity of the vehicles; solving and obtaining a dispatching scheme through employing a particle swarm optimization algorithm, wherein the mean waiting time of passengers and the mean on-bus time of passengers are as short as possible in the scheme, the mean seating capacity of the vehicles are as large as possible in the scheme, and the scheme comprises a departure interval and a departure type.

Description

A kind of quick public transport combined schedule method that variable interval is dispatched a car

Technical field

The invention belongs to public transport optimizing scheduling technical field, particularly relate to a kind of quick public transport combined schedule method that variable interval is dispatched a car.

Background technology

Along with the fast development of China's economy and urbanization process, Urban vehicles poputation rapidly increases, and traffic resource supplies wretched insufficiency.But China's distinctive " compound formula " Land-Use makes a lot of region be difficult to effectively be covered by traditional public transportation system, occurs that the zone of action such as settlement, office is away from phenomenons such as the public traffic stations such as public transport, subway.Just under the guide of this demand, the theory of " micro-public transit system " is arisen at the historic moment.It with periphery regular public traffic Seamless linkage, effectively solves the trip problem of " compound " interior resident, significantly reduces walking distance by improving " compound " inner microcirculation, reduce the travel time.Bus dispatching is then one of most important link in microcirculation.

Bus dispatching in existing micro-public transit system is often too simple, is difficult to tackle the problem that in micro-public transit system, the volume of the flow of passengers is concentrated.After introducing quick public transport, the array mode of bus rapid transit and common public transport also often only paid close attention to by existing model, adopt and simply dispatch a car at equal intervals, and such scheduling mode efficiency is low, the requirement of micro-system to passenger flow affordability and vehicle punctuality rate can not be met far away, usually occur the phenomenon such as " bunching ", " large-spacing " between bus.Therefore, the public transport utilization factor under current micro-system does not reach expectation value far away, and a lot of resident still selects private car to go on a journey.

Summary of the invention

In order to optimize the departure interval between the array mode of quick public transport and common bus and vehicle further, reduce the average Waiting time of passenger and in the car time, improve bus cabin factor, overcome the problem that existing quick public transport scheduling model only pays close attention to vehicle combination mode, the present invention proposes a kind of quick public transport combined schedule method that variable interval is dispatched a car, comprising:

Step 1: determine the section and the time period that need research, comprise website sum, total degree of dispatching a car; And obtain the running time of vehicle between website, the passenger flow information in this section; Determine the spended time of getting on the bus of every passenger, spended time of getting off, vehicle parking elapsed time;

Step 2: according to the passenger flow information in this section, sorting-out in statistics obtains the ridership of getting on or off the bus of each website, is quick public transport website or common bus stop according to ridership determination type of site of getting on or off the bus;

Step 3: with the departure interval between the array mode of quick public transport and common car and vehicle for decision variable, set up bus dispatching model, calculates each vehicle at the berthing time of each website and the ridership of getting on or off the bus at each website;

Step 4: according to each vehicle obtained at the berthing time of each website and the ridership of getting on or off the bus at each website, obtain objective function expression formula, namely calculate whole section within the time period of research: the average Waiting time of passenger, passenger are on average car time and the average seating capacity of vehicle;

Step 5: use particle swarm optimization algorithm model, make the average Waiting time of passenger, passenger on average little as far as possible in the car time, the average seating capacity of vehicle is large as far as possible, thus obtains one and comprise the departure interval and the scheduling scheme of type of dispatching a car.

Described passenger flow information by adding up on the spot and estimating acquisition, or is obtained automatically by bus card-reading ticket sale system.

Described step 3 comprises:

Step 301: calculate moment when vehicle arrives at a station; And the Customer information on this moment car and the passenger flow information on platform;

Step 302: calculate in non-overloading situation, passenger getting on/off number and the time spent;

Step 303: moment when calculating vehicle is leaving from station; And the Customer information on this moment car and the passenger flow information on platform.

Described step 4 comprises:

Step 401: calculate whole section average Waiting time W of passenger within the time period of research ₁;

Step 402: calculate whole section research time period in passenger on average at car time W ₂;

Step 403: calculate whole section average seating capacity W of vehicle within the time period of research ₃;

Step 404: by W ₁, W ₂, W ₃be added by certain weight and namely obtain objective function.

The present invention compared with prior art, has the following advantages:

In micro-public transit system, introduce quick public transport, it and common bus are combined and dispatches a car, vehicle operation more single than traditional employing, better can solve the problem that indivedual website volume of the flow of passengers is concentrated.

The constraint that the breakthrough tradition departure interval is fixing, adopts changing distance to dispatch a car, alleviates the load in section, peak, the more effective appearance avoiding " bunching " between bus, " large-spacing " phenomenon.

Proposition vehicle combination mode and departure interval are optimized simultaneously first, have better effect of optimization, be more conducive to the saving of passenger's time cost and the expansion of public transport company's profit of operation than existing bus dispatching optimized algorithm.

Embodiment

The present invention proposes a kind of quick public transport combined schedule method that variable interval is dispatched a car, comprising:

In step 1, according to actual conditions and needs, first determine website sum n and the total degree m that dispatches a car; Then according to the Distance geometry road conditions between adjacent two websites, the running time L from the i-th-1 station to the i-th station is determined _i.Afterwards, according to vehicle determination maximum passenger capacity M, estimate according to actual conditions time a that vehicle slows down consumed because of stop, time b that each passenger loading spends and the time c that each passenger getting off car spends.Finally, by adding up and estimating, draw the OD matrix { O of passenger flow on the spot _ij, O _ijarrive the i-th station in the representation unit time and the ridership at jth station will be removed.

In step 2, by the sorting-out in statistics to passenger flow OD data, obtain the ridership of getting on or off the bus of each website.Determine commuter rush hour website according to these data, and these websites are set to quick public transport website.These websites Boolean variable S _irepresent: S _i=1 represents that website i is express station, S _i=0 website i is not express station.

Step 3: with the array mode E of quick public transport and common car _k(E _k=0 represents that a kth car is common car, E _k=1 represents that a kth car is quick public transport) and vehicle between departure interval G _k(difference of the frequency of a kth car and the frequency of kth-1 car) is decision variable, set up bus dispatching model: when vehicle k arrives website i, the information that before utilizing, k-1 car and front i-1 stand, in conjunction with current passenger flow situation, calculate vehicle k at the berthing time of website i and the ridership of getting on or off the bus at this station.Utilize recurrence relation, just can obtain information of vehicles and the Customer information of system-wide section under full time domain.

In step 301, when vehicle k arrives the i-th station, one side now moment H _kiequal the moment H that vehicle arrives a upper station _{k (i-1)}add its berthing time T at a upper station _{k (i-1)}running time L afterwards _i.Especially, vehicle k arrives the moment H at the 1st station _k1it is the frequency of vehicle k with the running time L before first stop ₁sum.Recycling H _kithe mistiming F that vehicle k and vehicle k-1 arrives the i-th station can be obtained _ki.

$H_{ki}=\left\{\begin{array}{cc}{K}_{k(i-1)}+L_i+T_{k(i-1)},& i\≥2\\ \underset{k^{\′}=1}{\overset{k}{\Σ}}{G}_{k^{\′}}+L_1,& i=1\end{array}\right.---\left(1\right)$

$F_{ki}=\left\{\begin{array}{cc}{H}_{ki}-H_{(k-1)i},& k\≥2\\ H_{1i},& k=1\end{array}\right.---\left(2\right)$

On the other hand, now platform to remove the ridership D at jth station _kijto equal when a car leaves just ridership Q AT STATION _{(k-1) ij}the passenger O newly arrived during adding this _ij× (F _ki-T _{(k-1) i}), namely

$D_{kij}=\left\{\begin{array}{cc}{O}_{ij}(F_{ki}-T_{(k-1)i})+Q_{(k-1)ij},& k\≥2\\ O_{1j}{F}_{k1},& k=1\end{array}\right.---\left(3\right)$

Wherein, Q _kijrepresent vehicle k when leaving the i-th station, platform will remove the ridership at jth station.

In step 302, first the ridership V that gets off is calculated _ki.

$V_{ki}=\underset{j=1}{\overset{i-1}{\Σ}}{U}_{kji}---\left(4\right)$

Wherein, U _kjirepresent a kth car on jth station and want the ridership at the i-th station.

By the restriction of vehicle carrying capacity M, vacant position R in passenger getting off car rear car _kifor

$R_{ki}=\left\{\begin{array}{cc}M-X_{k(i-1)}+V_{ki},& i\≥2\\ M,& i=1\end{array}\right.---\left(5\right)$

And now want the ridership of getting on the bus to be likely be greater than remaining seat.When vehicle k is common car (1-E _k=1), time, want that the destination of getting on the bus be the ridership at jth station is D _kij; When vehicle k is express (E _k=1), time, want that the destination of getting on the bus be the ridership at jth station is D _kij× S _i× S _j.Therefore vehicle k intends to get on the bus when arriving the i-th station and destination is the ridership U ' at jth station _kijfor sum of the two.The ridership U ' got on the bus is intended when vehicle k arrives the i-th station _kifor U ' _kijsum.

U′ _kij＝D _kij(S _iS _jE _k+(1-E _k))(6)

$U_{ki}^{\′}=\underset{j=i+1}{\overset{n}{\Σ}}{U}_{kij}^{\′}---\left(7\right)$

We use t _kirepresent the ratio of getting on the bus of passenger.Utilize t _kiand then this car can have been obtained and destination is the ridership U at jth station _kij, and on this station total ridership U of this car _ki.

$t_{ki}=\left\{\begin{array}{cc}1& R_{ki}\&GreaterEqual;U_{ki}^{\&prime;}>0\\ R_{ki}/U_{ki}^{\&prime;}& R_{ki}<U_{ki}^{\&prime;}\\ 0& U_{ki}^{\&prime;}=0\end{array}\right.---\left(8\right)$

U _kij＝ _kiU′ _kij(9)

$U_{ki}=\underset{j=i+1}{\overset{n}{\&Sigma;}}{U}_{kij}---\left(10\right)$

After vehicle arrives at a station, the time spent in the process of vehicle parking, passenger getting on/off is T _ki.If vehicle is common car (1-E _k=1) or vehicle is express and this station is the website (E of express _k× S _i=1), then have down time, its time equals deceleration time a and adds passenger loading spended time U _ki× b adds passenger getting off car spended time V _ki× c, namely

T _ki＝(1-E _k+S _iE _k)(a+bU _ki+cV _ki)(11)

In step 303, when vehicle leaves, platform to remove the ridership Q at jth station _kijequal the ridership arrived during ridership that ridership when vehicle k arrives deducted car adds this.

Q _kij＝D _kij-U _kij+O _ijT _ki(12)

And the ridership X now on car _kiequal vehicle from ridership X during the i-th-1 station _{k (i-1)}add the ridership U got on the bus at this station _kiand deduct the ridership V got off at this station _ki, namely

$X_{ki}=\left\{\begin{array}{cc}{X}_{k(i-1)}+U_{ki}-V_{ki},& i\&GreaterEqual;2\\ U_{k1},& i=1\end{array}\right.---\left(13\right)$

In step 401, calculate the average Waiting time of passenger, first calculate the total Waiting time t of passenger.It equals each car on each platform and gets to the station apart from a upper car and to get to the station the total stand-by period sum of passenger during this period of time.On i-th platform, vehicle k-1 arrive after to vehicle k arrival before during this period of time in: have position passenger arrives at a upper car and just gets to the station, and removes the passenger U got on the bus in a upper station _{(k-1) i}, all the other people are always upper AT STATION waits for that their total waiting time is until this car arrives have position passenger arrives in the meantime, and their stand-by period is there is U _{(k-1) i}position passenger when upper car arrives on car, their average latency is the time that car comes to a complete stop add the time of queuing up and getting on the bus, namely total waiting time is

$t=\underset{i=2}{\overset{n}{\&Sigma;}}\underset{k=1}{\overset{m}{\&Sigma;}}(t_{ik}^{\left(1\right)}+t_{ik}^{\left(2\right)}+t_{ik}^{\left(3\right)})---\left(14\right)$

$t_{ik}^{\left(1\right)}=\left\{\begin{array}{cc}{F}_{ki}\&times;(-U_{(k-1)i}+\underset{j=i+1}{\overset{n}{\&Sigma;}}{D}_{(k-1)ij}),& k\&GreaterEqual;2\\ 0,& k=1\end{array}\right.---\left(15\right)$

$t_{ik}^{\left(2\right)}=\underset{j=i+1}{\overset{n}{\&Sigma;}}(O_{ij}\&times;F_{ki})\&times;\frac{F_{ki}}{2}---\left(16\right)$

$t_{ik}^{\left(3\right)}=\left\{\begin{array}{cc}{U}_{(k-1)i}(\frac{a}{2}+\frac{b}{2}{U}_{(k-1)i}+{\mathrm{cV}}_{(k-1)i}),& k\&GreaterEqual;2\\ 0,& k=1\end{array}\right.---\left(17\right)$

Calculate total ridership O again.It is the arrival rate of passenger at the i-th station be multiplied by m car to get to the station the moment H of i _misum.

$O=\underset{i=1}{\overset{n-1}{\&Sigma;}}\left(H_{mi}\underset{j=i+1}{\overset{n}{\&Sigma;}}{O}_{ij}\right)---\left(18\right)$

Therefore about the cost W of the average Waiting time equivalence of passenger ₁:

$W_1=\frac{t}{O}---\left(19\right)$

In step 402, total seating capacity U is first calculated.

$U=\underset{i=1}{\overset{n-1}{\&Sigma;}}\underset{k=1}{\overset{m}{\&Sigma;}}{U}_{ki}---\left(20\right)$

What we paid close attention to is time that vehicle delays because stopping AT STATION is on the impact of passenger on car, and the running time that vehicle on the way must spend is not for we is concerned about.Therefore we define passenger on average at car time factor W ₂, weigh passenger in the car time with it.Its definition is such as formula (21). represent that a kth car reaches the time of the actual cost in jth station and the ratio of desirable shortest time from the i-th station; And then, represent the ratio of time that all passengers " wait for " onboard and ideal time.This ratio is passenger on average in car time factor divided by total carrying number U again.It reflects passenger onboard because of car stop, other passenger getting on/offs and the time length that delays.

$W_2=\frac{{\mathrm{\&Sigma;}}_{k=1}^m{\mathrm{\&Sigma;}}_{i=1}^{n-1}{\mathrm{\&Sigma;}}_{j=i+1}^n{U}_{kij}\&times;\frac{H_{kj}-H_{ki}}{{\mathrm{\&Sigma;}}_{i^{\&prime;}=i+1}^j{L}_{i^{\&prime;}}}}{U}---\left(21\right)$

In step 403, the average seating capacity W of public transport company's vehicle in use ₃for total carrying number is divided by section sum and vehicle fleet.

$W_3=\frac{U}{m(n-1)}---\left(22\right)$

In step 404, objective function W is made up of three parts:

maxW＝A ₃×W ₃-A ₁×W ₁-E ₂×W ₂(23)

Wherein, A ₁it is the cost coefficient of the average Waiting time of passenger; A ₂on average at the cost coefficient of car time; A ₃it is the income coefficient of the average seating capacity of vehicle.

In steps of 5, particle cluster algorithm is the algorithm of an iteration optimizing, and it utilizes the random walk of population in space to find the optimum solution of optimization problem.Because control variable in this model has two, be respectively Boolean variable E _kwith positive integer number variable G _k, so our particle swarm optimization algorithm of taking " integer, scale-of-two " to mix, concrete steps are:

(1) particle number is determined, the position of random initializtion particle.Due to E _kand G _krespectively have m, therefore particle length is 2m.

(2) iterative formula is used to calculate the speed of each particle and new position.Use X _i=(x _{i, 1}, x _{i, 2}..., x _{i, 2m}) represent particle position, V _i=(v _{i, 1}, v _{i, 2}..., v _{i, 2m}) representing particle rapidity, then iterative formula is:

$\begin{array}{c}{v}_{id}^{k+1}=\mathrm{\&chi;}({\mathrm{\&omega;v}}_{id}^k+c_1{\mathrm{rand}}_1({\mathrm{pbest}}_{id}-x_{id}^k)\\ +c_2{\mathrm{rand}}_2\left({\mathrm{gbest}}_d-x_{id}^k\right))\end{array}---\left(24\right)$

$x_{id}^{k+1}=\left\{\begin{array}{cc}1,& i\&le;m{\mathrm{and\&rho;}}_{id}^{k+1}<sig\left(v_{id}^k\right)\\ 0,& i\&le;m{\mathrm{and\&rho;}}_{id}^{k+1}\&GreaterEqual;sig\left(v_{id}^k\right)\\ round(x_{id}^k+v_{id}^k),& i>m\end{array}\right.---\left(25\right)$

$sig\left(v_{id}^k\right)=\frac{1}{1+e^{-v_{id}^k}}---\left(26\right)$

$x_{id}^k\&Element;\&lsqb;x_{min},x_{max}\&rsqb;,---\left(28\right)$

$v_{id}^k\&Element;\&lsqb;-v_{max},v_{max}\&rsqb;---\left(29\right)$

the speed of particle i d dimension in kth time iteration; c ₁, c ₂it is accelerator coefficient; Rand ₁, rand ₂it is the random number between [0,1]; it is the current location of particle i d dimension in kth time iteration; Pbest _idthe position of the individual extreme point that to be particle i tie up at d; Gbest _dthe position of the global extremum point that to be whole group tie up at d; Round () is bracket function; it is the random number between [0,1]; χ is compressibility factor, and it contributes to guaranteeing PSO algorithm convergence; ω is inertia weight, controls the impact of speed above on present speed with inertia weight.

(3) reposition of more all particles with the desired positions pbest that this particle has been to _idfitness, if fitness larger, then the desired positions of more all particles, upgrades colony desired positions gbest _d.

(4) get back to step (2), until algorithm convergence, or reach iterations.

This embodiment is only the present invention's preferably embodiment; but protection scope of the present invention is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the present invention discloses, the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.

Claims (4)

1. a variable interval quick public transport combined schedule method of dispatching a car, is characterized in that, comprising:

Step 1: determine the section and the time period that need research, comprise website sum, total degree of dispatching a car; And obtain the running time of vehicle between website, the passenger flow information in this section; Determine the spended time of getting on the bus of every passenger, spended time of getting off, vehicle parking elapsed time;

Step 2: according to the passenger flow information in this section, sorting-out in statistics obtains the ridership of getting on or off the bus of each website, is quick public transport website or common bus stop according to ridership determination type of site of getting on or off the bus;

Step 3: with the departure interval between the array mode of quick public transport and common car and vehicle for decision variable, set up bus dispatching model, calculates each vehicle at the berthing time of each website and the ridership of getting on or off the bus at each website;

Step 4: according to each vehicle obtained at the berthing time of each website and the ridership of getting on or off the bus at each website, obtain objective function expression formula, namely calculate whole section within the time period of research: the average Waiting time of passenger, passenger are on average car time and the average seating capacity of vehicle;

Step 5: use particle swarm optimization algorithm model, make the average Waiting time of passenger, passenger on average little as far as possible in the car time, the average seating capacity of vehicle is large as far as possible, thus obtains one and comprise the departure interval and the scheduling scheme of type of dispatching a car.

2. method according to claim 1, is characterized in that, described passenger flow information by adding up on the spot and estimating acquisition, or is obtained automatically by bus card-reading ticket sale system.

3. method according to claim 1, it is characterized in that, described step 3 comprises:

Step 301: calculate moment when vehicle arrives at a station; And the Customer information on this moment car and the passenger flow information on platform;

Step 302: calculate in non-overloading situation, passenger getting on/off number and the time spent;

Step 303: moment when calculating vehicle is leaving from station; And the Customer information on this moment car and the passenger flow information on platform.

4. method according to claim 1, it is characterized in that, described step 4 comprises:

Step 401: calculate whole section average Waiting time W of passenger within the time period of research ₁;

Step 402: calculate whole section research time period in passenger on average at car time W ₂;

Step 403: calculate whole section average seating capacity W of vehicle within the time period of research ₃;

Step 404: by W ₁, W ₂, W ₃be added by certain weight and namely obtain objective function.