CN114758506B - Method and device for cooperatively controlling variable speed limit and ramp current limiting of expressway confluence area - Google Patents
Method and device for cooperatively controlling variable speed limit and ramp current limiting of expressway confluence area Download PDFInfo
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- G08G1/0104—Measuring and analyzing of parameters relative to traffic conditions
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Abstract
The invention discloses a method and a device for cooperatively controlling variable speed limit and ramp current limiting of an expressway confluence area. The method is mainly used for urban expressway confluence areas. In the method: according to the upstream and downstream relation, the road segments are coded and divided; taking data such as occupancy, speed and the like acquired from traffic data acquisition equipment of each lane as model input, and constructing a lane-level traffic flow basic diagram; acquiring the real-time occupancy of a confluence area, and performing ramp current-limiting control; the real-time occupancy rate at the entrance of the ramp is acquired, the queue tail control is carried out, the queuing overflow of the ramp is effectively prevented, meanwhile, the expressway mainline lane level variable speed limit is carried out by depending on the traffic data at the traffic zone lane level, the phenomenon that the traffic flow capacity is reduced due to overlarge instantaneous flow of the traffic zone after the queue tail control is carried out is prevented, and the traffic efficiency is effectively improved.
Description
Technical Field
The invention relates to the technical field of intelligent traffic, in particular to a method and a device for cooperatively controlling variable speed limit and ramp current limiting of an expressway confluence area.
Background
The urban expressway is an important component of an intelligent traffic system, and in the morning and evening peak period, an expressway junction area plays a role of a traffic bottleneck, and traffic disturbance phenomena such as vehicle stop and walk, traffic capacity reduction (capacity drop) and the like exist. The traffic disturbance phenomenon not only further aggravates traffic jam and brings economic loss, but also has negative effects on environment and traffic safety. Therefore, there is an urgent need to research the control means of the fast-path merging area.
In the early stage of traffic engineering development, the improvement of traffic efficiency mainly depends on the construction of infrastructure. Nowadays, with the reduction of available land and the rapid increase of the number of vehicles, the method for alleviating congestion through construction means such as road expansion is not efficient, so that intelligent traffic control plays an increasingly important role in traffic control means. In recent years, intelligent traffic is rapidly developed, and traffic jam is slowed down, and traffic transportation efficiency and travel experience are improved by changing the space-time distribution mode of limited road resources by traffic control means such as ramp flow limiting, traffic induction and lane changing. The ramp current-limiting control method slows down the congestion of the merging area of the express way by limiting the traffic flow imported from the ramp.
Currently, most ramp current-limiting methods are timing strategies in actual engineering operation, that is, ramp current-limiting timing schemes are designed according to historical traffic flow of the area, however, the effect of the schemes cannot adapt to dynamic traffic demands and flow, and therefore a self-adaptive ramp current-limiting control scheme is needed. However, at present, most of the adaptive ramp current-limiting control methods only consider the control of limiting the traffic volume of the incoming traffic on the ramp, and do not fully consider the queuing bearing capacity of the ramp. In practical situations, due to the application of the ramp current-limiting control algorithm, teams on the ramps may overflow to the ground trunk road or the diversion area of the overpass. Therefore, a part of algorithms provide a ramp queue tail control method, and overflow of queues on the ramps is effectively prevented. However, due to the control of the tail of the ramp, a large amount of traffic on the ramp is converged into the confluence area of the express way in a short time, which easily causes the phenomenon of traffic flow capacity reduction. The variable speed-limiting control means controls the traffic flow of the confluence area by slowing down the traffic flow speed of the main road of the express way in advance, and can effectively slow down the phenomenon of traffic flow capacity reduction. Therefore, the control method combining the variable speed limit and the ramp current limit has the effects of improving the traffic efficiency and relieving the phenomenon of traffic flow capacity reduction.
In the method, firstly, road sections are coded and divided according to the upstream and downstream relation, historical data such as occupancy, speed and the like acquired from traffic data acquisition equipment are used as input, the traffic flow-density-speed relation is acquired, and a lane-level traffic basic map is constructed. The real-time occupancy rate at the entrance of the ramp is acquired, the queue tail control is carried out, the queuing overflow of the ramp is effectively prevented, meanwhile, the expressway mainline lane level variable speed limit is carried out by depending on the traffic data at the traffic zone lane level, the phenomenon that the traffic flow capacity is reduced due to overlarge instantaneous flow of the traffic zone after the queue tail control is carried out is prevented, and the traffic efficiency is effectively improved.
Disclosure of Invention
The invention aims to provide a method and a device for cooperatively controlling variable speed limit and ramp current limiting of a confluence area of an express way aiming at the defects of the prior art.
The purpose of the invention is realized by the following technical scheme: a variable speed limit and ramp current limiting cooperative control method for an expressway confluence area comprises the following steps:
the method comprises the following steps: coding and dividing the express way, and installing equipment;
step two: data collection and analysis are carried out depending on the installed equipment, and lane-level traffic flow indexes of different areas of the express way are obtained according to the codes of the express way in the step one;
step three: and performing variable speed limit and ramp current limit cooperative control according to lane-level traffic flow indexes of different areas of the express way.
Further, the first step specifically comprises:
(1.1) carrying out coding division on the express way: the express way is divided into four parts: a variable speed-limiting area V, an accelerating area A, a confluence area M and a ramp area R; the variable speed-limiting area V is an upstream section of the main road of the express way, the main road of the express way is an intermediate section of the main road of the express way, the confluence area M is a downstream section of the main road of the express way, and the ramp area R is a ramp of the express way;
(1.2) arranging a coil detector on each lane of the variable speed-limiting area V, and obtaining real-time traffic flow data of the variable speed-limiting area V; arranging a variable speed limit information board at the starting point of each lane of the variable speed limit area V, wherein the variable speed limit information board is used for issuing a variable speed limit instruction and is arranged on a traffic portal frame; laying a coil detector on each lane of the confluence area M for acquiring real-time traffic flow data of the confluence area M; arranging a coil detector on each lane of the ramp region R for acquiring real-time traffic flow data of the ramp region R; and arranging a ramp current-limiting signal device at the end point of each lane of the ramp region R, and adjusting a signal lamp to achieve the aim of ramp current limiting.
Further, the second step is specifically:
(2.1) obtaining lane-level traffic flow indexes according to traffic flow data of the variable speed-limiting area V, wherein the lane-level traffic flow indexes comprise traffic flow density and traffic flow, and calculating to obtain saturated flow Q of the variable speed-limiting area V v Traffic flow speed w v Free flow velocity u v Density of congestion k v_j Critical density k v_c Constructing a triangular traffic flow basic diagram of the variable speed limit area V under a normal state; and obtaining the optimal occupancy o of the variable speed limit area V v_c ，
；
(2.2) acquiring a lane-level traffic flow index according to the traffic flow data of the confluence area M, and calculating to obtain the saturated flow Q of the confluence area M m Traffic flow speed w m Free flow velocity u m Density of congestion k m_j Critical density k m_c Constructing a triangle traffic flow basic diagram of the confluence area M under a normal state; and the optimum occupancy rate o of the confluence region M is obtained m_c ，
；
(2.3) obtaining a lane-level traffic flow index according to the traffic flow data of the ramp area R, and calculating to obtain the saturated flow Q of the ramp area R r Traffic flow speed w r Free flow velocity u r Density of congestion k r_j Key point ofDensity k r_c Constructing a triangular traffic flow basic diagram of the ramp region R under a normal state; and the optimal occupancy rate o of the ramp area R is obtained r_c ，
。
Further, the third step is specifically:
(3.1) every T seconds as a control cycle length;
(3.2) before the current control period starts, judging to adopt a ramp current-limiting control strategy or a variable speed-limiting control strategy:
if the actual traffic occupancy of the ramp region R in the previous control period is greater than a% of the preset traffic occupancy, a variable speed limit control strategy is adopted in the current whole control period;
if the actual traffic occupancy of the ramp region R in the previous control period is less than a% of the preset traffic occupancy, adopting a ramp current-limiting control strategy in the current whole control period;
and (3.3) after the current control period is finished, returning to the step (3.2) and entering a new control period.
Further, the variable speed limit control strategy is specifically as follows:
a1) in the current whole control period, ramp current-limiting signal equipment arranged at the end point of a ramp region R always displays green light;
a2) the speed limit value displayed by the speed limit changing information board of the main road lane of the express way which is not closest to the ramp is as follows:
if the average occupancy of the variable speed-limit zone V in the previous control period is less than
Wherein, in the step (A),
if so, in the current whole control period, the variable speed limit information board of the lane displays the original speed limit value of the main road of the express way;
if the level of the variable speed-limit zone V in the previous control periodAverage occupancy rate of more than
If the speed limit value displayed by the variable speed limit information board of the lane is v in the current whole control period vsl ，
；
a3) The speed limit value displayed by the speed limit changing information board of the main road lane of the express way closest to the ramp is as follows:
if the average occupancy of the lane in the previous control period is less than
Wherein n is the number of lanes of the main road of the express way, and the variable speed limit information board of the lanes displays the original speed limit value of the main road of the express way in the current whole control period;
if the average occupancy rate of the lane in the previous control period is larger than
If the speed limit value displayed by the variable speed limit information board of the lane is v in the current whole control period vsl-s ，
。
Further, the ramp current-limiting control strategy specifically includes:
b1) in the current whole control period, the variable speed limit information boards of all lanes of the main road of the express way display the original speed limit value of the main road of the express way;
b2) obtaining the average occupancy rate o of the confluence region M of the previous control period m And the current limiting value of ramp region R
Calculating the current limiting value of the ramp region R in the current control period as R,
wherein, K is R The flow convergence range is adjustable parameters, the value range is 45-80, and the flow convergence range can be flexibly adjusted according to the length of the flow convergence region M and the habit of local drivers;
b3) corresponding the ramp region R current limiting value R in the current whole control period to the traffic light duration of the ramp current limiting signal equipment;
if the current limiting value R is smaller than the saturated flow Q of the ramp region R r Then the ramp current-limiting signal equipment always displays green light in the whole control period;
if the current limiting value R is larger than the saturated flow Q of the ramp region R r And the time of the ramp current-limiting signal device displaying green light in the whole control period is T r/Q r And the rest of the time shows a red light.
The invention also provides a device for cooperatively controlling the variable speed limit and the ramp current-limiting in the confluence area of the express way, which comprises one or more processors and is used for realizing the method for cooperatively controlling the variable speed limit and the ramp current-limiting in the confluence area of the express way.
The invention also provides a computer readable storage medium, which stores a program, and the program is used for realizing the speed-limiting and ramp current-limiting cooperative control method in the speed-merging area when being executed by a processor.
The invention has the beneficial effects that: according to the method, the real-time occupancy rate of the ramp entering the main road is acquired through the real-time linkage of the variable speed limit of the main road of the express way and the flow limiting control of the ramp of the express way, and the queue tail control is carried out, so that the queuing overflow of the ramp is effectively prevented; meanwhile, by means of the merging area lane level traffic data, the expressway main line lane level variable speed limit is carried out, and the phenomenon that the traffic flow capacity is reduced due to overlarge instantaneous flow of a merging area after team tail control is carried out is prevented, so that the traffic efficiency is effectively improved. The invention not only ensures that the team of the ramp does not overflow, but also ensures the passing efficiency of the main line of the expressway, thereby reducing the average traffic delay.
Drawings
FIG. 1 is a schematic flow chart of a method for cooperative control of a variable speed limit and a ramp current limit in an expressway merge area according to the present invention;
FIG. 2 is a schematic diagram of the fast path code division;
FIG. 3 is a schematic view of the installation of the apparatus;
FIG. 4 is a basic diagram of a normal triangular traffic flow;
fig. 5 is a structural diagram of a variable speed limit and ramp current-limiting cooperative control device of an expressway confluence area provided by the invention.
Detailed Description
For purposes of promoting an understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description of the embodiments taken in conjunction with the accompanying drawings, it being understood that the specific embodiments described herein are illustrative of the invention and are not intended to be exhaustive. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, are within the scope of the present invention.
The invention aims to provide a method for cooperatively controlling variable speed limit and ramp current limiting of a confluence area of an express way, aiming at the problem that the traffic flow of the confluence area is easy to drop suddenly due to the defects of the existing ramp current limiting control technology. In the method, firstly, the express way is coded and divided and equipment is installed; data acquisition and analysis are carried out by depending on the installed equipment, and lane-level traffic flow indexes of different areas of the express way are obtained; the real-time occupancy rate of the ramp entrance is obtained, the queue tail control is carried out, the ramp queuing overflow is effectively prevented, meanwhile, the variable speed limit of the main road of the express way is carried out by depending on the real-time traffic flow data of the confluence area, the overlarge instantaneous flow of the confluence area is prevented after the queue tail control is carried out, the traffic flow steep drop is slowed down, and the traffic efficiency is effectively improved.
Example 1
As shown in fig. 1, the present invention provides a method for cooperative control of a variable speed limit and a ramp current limit in a highway confluence region, comprising the following steps:
the method comprises the following steps: and coding and dividing the express way, and installing equipment.
The first step is realized by the following substeps:
(1.1) carrying out coding division on the express way: the express way is divided into four parts: a variable speed-limiting area V, an accelerating area A, a confluence area M and a ramp area R; the variable speed-limiting area V is an upstream section of the main road of the express way, the main road of the express way is an intermediate section of the main road of the express way, the confluence area M is a downstream section of the main road of the express way, and the ramp area R is a ramp of the express way.
The express way can be divided into an express way main road and an express way ramp, the express way main road is divided into a variable speed-limiting area V, an accelerating area A and a converging area M from upstream to downstream, and the express way ramp is divided into a ramp area R, as shown in fig. 2.
The method comprises the following steps that vehicles on a main road of the express way firstly pass through a variable speed limit area V, and the speed of the vehicles is determined according to a real-time variable speed limit instruction; after passing through the variable speed limit area V, the vehicle enters the acceleration area A, and the real-time variable speed limit instruction is that when the vehicle on the expressway merges with the vehicle on the ramp, the real-time variable speed limit instruction can be carried out at a speed close to the free flow, so that the vehicle speed difference with the flow on the ramp is reduced, and the safety risk is reduced; after passing through the acceleration region a, the vehicle enters the merging region M. And the vehicles on the ramp of the express way enter a ramp area R from the city street, carry out driving operation according to a ramp current-limiting instruction, then enter a confluence area M and converge into the main road of the express way.
(1.2) arranging a coil detector on each lane of the variable speed-limiting area V, wherein the coil detector is used for acquiring real-time traffic flow data of the variable speed-limiting area V; arranging a variable speed limit information board at the starting point of each lane of the variable speed limit area V, wherein the variable speed limit information board is used for issuing a variable speed limit instruction and is arranged on a traffic portal frame; laying a coil detector on each lane of the confluence area M for acquiring real-time traffic flow data of the confluence area M; arranging a coil detector on each lane of the ramp region R for acquiring real-time traffic flow data of the ramp region R; and arranging a ramp current-limiting signal device at the end point of each lane of the ramp region R, and adjusting a signal lamp to achieve the aim of ramp current limiting, as shown in FIG. 3.
Step two: and (4) carrying out data acquisition and analysis by depending on the installed equipment, and obtaining lane-level traffic flow indexes of different areas of the express way according to the codes of the express way in the step one.
The second step is realized by the following substeps:
the construction of the triangular traffic flow basic diagram of one area is realized by the following specific methods: according to traffic flow data of an area, lane-level indexes such as traffic flow density k and traffic flow q in a period of time are obtained, and a relational expression of the traffic flow q and the traffic flow density k is obtained through fitting
Calculating the saturated flow Q, the traffic flow speed w, the free flow speed u and the jam density k according to the relational expression j Critical density k c And constructing a triangular traffic flow basic diagram under normal state by using the indexes, wherein,
。
as shown in fig. 4, when the traffic flow density is high
When the vehicle is in a free flow traffic flow, the traffic flow q rises linearly along with the rise of the traffic flow density k; when the traffic flow density
When the vehicle is in the traffic flow in the congestion state, the traffic flow q linearly decreases with the increase of the traffic flow density k.
(2.1) obtaining lane-level traffic flow indexes according to traffic flow data of the variable speed-limiting area V, wherein the lane-level traffic flow indexes comprise traffic flow density and traffic flow, and calculating to obtain saturated flow Q of the variable speed-limiting area V v Traffic flow speed w v Free flow velocity u v Density of congestion k v_j Critical density k v_c Constructing a triangular traffic flow basic diagram of the variable speed limit area V under a normal state; and the optimal occupancy rate o of the variable speed limit area V is obtained v_c ，
；
(2.2) acquiring a lane-level traffic flow index according to the traffic flow data of the confluence area M, and calculating to obtain the saturated flow Q of the confluence area M m Traffic flow speed w m Free flow velocity u m Density of congestion k m_j Critical density k m_c Constructing a triangle traffic flow basic diagram of the confluence area M under a normal state; and obtaining the optimal occupancy rate o of the confluence region M m_c ，
；
(2.3) obtaining a lane-level traffic flow index according to the traffic flow data of the ramp area R, and calculating to obtain the saturated flow Q of the ramp area R r Traffic flow speed w r Free flow velocity u r Density of congestion k r_j Critical density k r_c Constructing a triangular traffic flow basic diagram of the ramp region R under a normal state; and the optimal occupancy rate o of the ramp region R is obtained r_c ，
。
Step three: and performing variable speed limit and ramp current limit cooperative control according to lane-level traffic flow indexes of different areas of the express way.
The third step is realized by the following substeps:
(3.1) every T seconds as a control cycle length;
(3.2) before the current control period starts, judging to adopt a ramp current-limiting control strategy or a variable speed-limiting control strategy:
if in the last control period: (
) If the actual traffic occupancy of the ramp area R is greater than a% of the preset traffic occupancy, (b) in the current whole control period
) Using variable speed limit control strategies(ii) a In the last control period, the actual traffic occupancy of the ramp area R is greater than a% of the preset traffic occupancy, it can be considered that the queuing length of the ramp area R exceeds a reasonable value, and the ramp area R may overflow to the ground street to cause congestion of the main road of the ground street, therefore, the ramp current-limiting control strategy is not adopted in this case, vehicles in the ramp area R flow into the merging area M at a saturated flow rate, and there is a risk of reducing the traffic capacity of the merging area M, and therefore, the traffic flow of the main road of the express way needs to be controlled at this time, (in the current whole control period), (in the current control period, the actual traffic flow of the ramp area R is determined to be higher than the preset traffic occupancy, and the vehicle is determined to be in the merging area M at this time
) Adopting a variable speed limit control strategy;
if in the last control period: (
) If the actual traffic occupancy of the ramp area R is less than a% of the preset traffic occupancy, (b) in the current whole control period
) Adopting a ramp current-limiting control strategy; the actual traffic occupancy of the ramp region R in the previous control period is less than a% of the preset traffic occupancy, so that the queuing length of the ramp region R does not exceed a reasonable value, and the ramp region R is unlikely to overflow to a ground street, and therefore a ramp current-limiting control strategy is adopted in the current whole control period;
the variable speed limit control strategy specifically comprises the following steps:
a1) in the current whole control period, ramp current-limiting signal equipment arranged at the end point of a ramp region R always displays green light;
a2) the speed limit value displayed by the speed limit changing information board of the main road lane of the express way which is not closest to the ramp is as follows:
if the average occupancy of the variable speed-limit zone V in the previous control period is less than
Wherein, in the process,
if so, in the current whole control period, the variable speed limit information board of the lane displays the original speed limit value of the main road of the express way;
if the average occupancy of the variable speed-limit zone V in the previous control period is larger than
If the speed limit value displayed by the variable speed limit information board of the lane is v in the current whole control period vsl ，
；
a3) The speed limit value displayed by the speed limit changing information board of the main road lane of the express way closest to the ramp is as follows:
if the average occupancy of the lane in the previous control period is less than
Wherein n is the number of lanes of the main road of the express way, and the variable speed limit information board of the lanes displays the original speed limit value of the main road of the express way in the current whole control period;
if the average occupancy of the lane in the last control cycle is larger than
If the speed limit value displayed by the variable speed limit information board of the lane is v in the current whole control period vsl-s ，
。
The ramp current-limiting control strategy specifically comprises the following steps:
b1) in the current whole control period, the variable speed limit information boards of all lanes of the main road of the express way display the original speed limit value of the main road of the express way;
b2) obtaining the average occupancy rate o of the confluence region M of the previous control period m And the current limiting value of ramp region R
Calculating the current limiting value of the ramp region R in the current control period as R,
wherein, K is R The parameter is adjustable, the value range is generally 45-80, and the parameter can be flexibly adjusted according to factors such as the length of the confluence area, the habit of local drivers and the like;
b3) corresponding the ramp region R current limiting value R in the current whole control period to the traffic light duration of the ramp current limiting signal equipment;
if the current limiting value R is smaller than the saturated flow Q of the ramp region R r Then the ramp current-limiting signal equipment always displays green light in the whole control period;
if the current limiting value R is larger than the saturated flow Q of the ramp region R r And the time of the ramp current-limiting signal device displaying green light in the whole control period is T r/Q r And the rest of the time shows a red light.
And (3.3) after the current control period is finished, returning to the step (3.2) and entering a new control period.
Example 2
The present invention is explained by using an embodiment 2 in which a main road of an expressway is 3 lanes, a ramp of the expressway is 1 lane, a ramp length is 1000m, a confluence region is 4 lanes, and a length is 100 m, as shown in fig. 3.
A variable speed limit and ramp current limiting cooperative control method for an expressway confluence area comprises the following steps:
the method comprises the following steps: coding and dividing the express way, and installing equipment;
the first step is realized by the following substeps:
(1.1) carrying out coding division on the express way: the express way is divided into four parts: a variable speed-limiting area V, an accelerating area A, a confluence area M and a ramp area R; the variable speed-limiting area V is an upstream section of the main road of the express way, the main road of the express way is an intermediate section of the main road of the express way, the confluence area M is a downstream section of the main road of the express way, and the ramp area R is a ramp of the express way.
The expressway is divided into an expressway main road and an expressway ramp, in the embodiment, the expressway main road is 3 lanes, the expressway ramp is 1 lane, and the ramp length is 1000 m;
the expressway can be divided into an expressway main road and an expressway ramp, the expressway main road is divided into a variable speed limiting area V, an accelerating area A and a converging area M from upstream to downstream, and the expressway ramp is divided into a ramp area R.
The method comprises the following steps that vehicles on a main road of the express way firstly pass through a variable speed limit area V, and the speed of the vehicles is determined according to a real-time variable speed limit instruction; after passing through the variable speed limit area V, the vehicle enters the acceleration area A, and the real-time variable speed limit instruction is that when the vehicle on the expressway merges with the vehicle on the ramp, the real-time variable speed limit instruction can be carried out at a speed close to the free flow, so that the vehicle speed difference with the flow on the ramp is reduced, and the safety risk is reduced; after passing through the acceleration region a, the vehicle enters the merging region M. And the vehicles on the ramp of the express way enter a ramp area R from the city street, carry out driving operation according to a ramp current-limiting instruction, then enter a confluence area M and converge into the main road of the express way.
(1.2) arranging a coil detector in each lane of the variable speed-limiting area V for acquiring real-time traffic flow data of the variable speed-limiting area V, wherein 3 coil detectors are arranged in the variable speed-limiting area V in the embodiment; arranging a variable speed limit information board at the starting point of each lane of the variable speed limit area V, wherein the variable speed limit information board is used for issuing a variable speed limit instruction and is arranged on a traffic portal frame, and 3 variable speed limit information boards are arranged at the starting point of the variable speed limit area V in the embodiment; laying a coil detector on each lane of the confluence area M for acquiring real-time traffic flow data of the confluence area M, wherein 4 coil detectors are laid in the confluence area M in the embodiment; a coil detector is arranged on each lane of the ramp region R and used for acquiring real-time traffic flow data of the ramp region R, and in this embodiment, 1 coil detector is arranged at the starting point of the ramp region R; a ramp current-limiting signal device is arranged at the end point of each lane of the ramp region R, and the ramp current-limiting target is achieved through the adjustment of a signal lamp, wherein 1 ramp current-limiting signal device is arranged at the end point of the ramp region R in the embodiment.
Step two: and (4) carrying out data acquisition and analysis by depending on the installed equipment, and obtaining lane-level traffic flow indexes of different areas of the express way according to the codes of the express way in the step one.
The second step is realized by the following substeps:
the construction of the triangular traffic flow basic diagram of one area is realized by the following specific methods: according to traffic flow data of an area, lane-level indexes such as traffic flow density k and traffic flow q in a period of time are obtained, and a relational expression of the traffic flow q and the traffic flow density k is obtained through fitting
Calculating the saturated flow Q, the traffic flow speed w, the free flow speed u and the jam density k according to the relational expression j Critical density k c And constructing a triangular traffic flow basic diagram under a normal state by using the indexes, wherein,
。
as shown in fig. 4, when the traffic flow density is high
When the vehicle is in a free flow traffic flow, the traffic flow q rises linearly along with the rise of the traffic flow density k; when the traffic flow density
When the vehicle is in a traffic flow in a congestion state, the traffic flow q linearly decreases with the increase of the traffic flow density k.
(2.1) obtaining lane-level traffic flow indexes according to traffic flow data of the variable speed-limiting area V, wherein the lane-level traffic flow indexes comprise traffic flow density and traffic flow, and calculating to obtain saturated flow Q of the variable speed-limiting area V v Traffic flow speed w v Free flow velocity u v Density of congestion k v_j Closing and openingBond Density k v_c Constructing a triangular traffic flow basic diagram of the variable speed limit area V under a normal state; and obtaining the optimal occupancy o of the variable speed limit area V v_c ，
；
(2.2) acquiring a lane-level traffic flow index according to the traffic flow data of the confluence area M, and calculating to obtain the saturated flow Q of the confluence area M m Traffic flow speed w m Free flow velocity u m Density of congestion k m_j Critical density k m_c Constructing a triangle traffic flow basic diagram of the confluence area M under a normal state; and the optimum occupancy rate o of the confluence region M is obtained m_c ，
；
(2.3) obtaining a lane-level traffic flow index according to the traffic flow data of the ramp area R, and calculating to obtain the saturated flow Q of the ramp area R r Traffic flow speed w r Free flow velocity u r Density of congestion k r_j Critical density k r_c Constructing a triangular traffic flow basic diagram of the ramp region R under a normal state; and the optimal occupancy rate o of the ramp area R is obtained r_c ，
。
In this embodiment, the triangular traffic flow basic diagrams of the 3 lanes in the variable speed limit region V are the same, and the optimal occupancy rate o of the variable speed limit region V v_c =0.2, saturated flow rate Q in variable speed-limiting region V v =2300 veh/h (number of vehicles/hour), traffic flow speed w v =25km/h, free flow velocity u m =100 km/h。
Step three: and performing variable speed limit and ramp current limit cooperative control according to lane-level traffic flow indexes of different areas of the express way.
The third step is realized by the following substeps:
(3.1) selecting T =40 seconds as a control period length;
(3.2) before the current control period starts, judging to adopt a ramp current-limiting control strategy or a variable speed-limiting control strategy:
if in the last control period: (
) If the actual traffic occupancy of the ramp area R is greater than a% of the preset traffic occupancy, (b) in the current whole control period
) Adopting a variable speed limit control strategy;
if in the last control period: (
) If the actual traffic occupancy of the ramp area R is less than a% of the preset traffic occupancy, (b) in the current whole control period
) Adopting a ramp current-limiting control strategy;
the variable speed limit control strategy specifically comprises the following steps:
a1) in the current whole control period, ramp current-limiting signal equipment arranged at the end point of a ramp region R always displays green light;
a2) the speed limit value displayed by the speed limit changing information board of the main road lane of the express way which is not closest to the ramp is as follows:
if the average occupancy of the variable speed-limit zone V in the previous control period is less than
Wherein, in the step (A),
if so, in the current whole control period, the variable speed limit information board of the lane displays the original speed limit value of the main road of the express way;
if the average of the variable speed-limit region V in the last control periodOccupancy ratio greater than
If the speed limit value displayed by the variable speed limit information board of the lane is v in the current whole control period vsl ，
；
a3) The speed limit value displayed by the speed limit changing information board of the main road lane of the express way closest to the ramp is as follows:
if the average occupancy of the lane in the previous control period is less than
Wherein n is the number of lanes of the main road of the express way, and the variable speed limit information board of the lanes displays the original speed limit value of the main road of the express way in the current whole control period;
if the average occupancy rate of the lane in the previous control period is larger than
If the speed limit value displayed by the variable speed limit information board of the lane is v in the current whole control cycle vsl-s ，
。
The ramp current-limiting control strategy specifically comprises the following steps:
b1) in the current whole control period, the variable speed limit information boards of all lanes of the main road of the express way display the original speed limit value of the main road of the express way;
b2) obtaining the average occupancy rate o of the confluence region M of the previous control period m And the current limiting value of ramp region R
Calculating the current limiting value of the ramp region R in the current control period as R,
wherein, K is R The parameter is adjustable, the value range is 45-80, and the parameter can be flexibly adjusted according to factors such as the length of the confluence area, the habit of local drivers and the like;
b3) corresponding the ramp region R current limiting value R in the current whole control period to the traffic light duration of the ramp current limiting signal equipment;
if the current limiting value R is smaller than the saturated flow Q of the ramp region R r Then the ramp current-limiting signal equipment always displays green light in the whole control period;
if the current limiting value R is larger than the saturated flow Q of the ramp region R r And the time of the ramp current-limiting signal device displaying green light in the whole control period is T r/Q r And the rest of the time shows a red light.
In the present embodiment, a is set to 50,
set to 0.8, K R Set to 70, period c of traffic light dur The setting was made for 40s of time,
(3.3) when the control period ends (T =0+ T), the process returns to step (3.2) and a new control period is entered.
And establishing a simulation environment for verification. In 15 minutes, generating a plurality of traffic flow scenes, and performing simulation verification to obtain the following average delay before and after the control scheme is adopted:
table 1: simulation data table
As can be seen from the table 1, the variable speed limit and ramp current limiting cooperative control method for the confluence area of the express way greatly reduces the vehicle forming time delay and brings significant benefits in practical engineering.
Corresponding to the embodiment of the method for cooperatively controlling the variable speed limit and the ramp current limiting of the expressway merge area, the invention also provides an embodiment of a device for cooperatively controlling the variable speed limit and the ramp current limiting of the expressway merge area.
Referring to fig. 5, the device for cooperatively controlling the variable speed limit and the ramp current limit in the merge area of the express way provided in the embodiment of the present invention includes one or more processors, and is used for implementing the method for cooperatively controlling the variable speed limit and the ramp current limit in the merge area of the express way in the above embodiment.
The embodiment of the variable speed limit and ramp current limiting cooperative control device for the expressway confluence area can be applied to any equipment with data processing capacity, and the any equipment with data processing capacity can be equipment or devices such as computers. The apparatus embodiments may be implemented by software, or by hardware, or by a combination of hardware and software. The software implementation is taken as an example, and as a logical device, the device is formed by reading corresponding computer program instructions in the nonvolatile memory into the memory for running through the processor of any device with data processing capability. From a hardware aspect, as shown in fig. 5, the present invention is a hardware structure diagram of any device with data processing capability where an express way merge region variable speed limit and ramp current limit cooperative control device is located, except for the processor, the memory, the network interface, and the nonvolatile memory shown in fig. 5, in an embodiment, any device with data processing capability where the device is located may also include other hardware according to an actual function of the any device with data processing capability, which is not described again.
The implementation process of the functions and actions of each unit in the above device is specifically described in the implementation process of the corresponding step in the above method, and is not described herein again.
For the device embodiments, since they substantially correspond to the method embodiments, reference may be made to the partial description of the method embodiments for relevant points. The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the scheme of the invention. One of ordinary skill in the art can understand and implement it without inventive effort.
The embodiment of the invention also provides a computer readable storage medium, wherein a program is stored on the computer readable storage medium, and when the program is executed by a processor, the method for realizing the cooperative control of the variable speed limit of the expressway confluence area and the ramp current limiting in the embodiment is realized. The computer readable storage medium may be an internal storage unit, such as a hard disk or a memory, of any data processing capability device described in any of the foregoing embodiments. The computer readable storage medium may also be any external storage device of a device with data processing capabilities, such as a plug-in hard disk, a Smart Media Card (SMC), an SD Card, a Flash memory Card (Flash Card), etc. provided on the device. Further, the computer readable storage medium may include both an internal storage unit and an external storage device of any data processing capable device. The computer-readable storage medium is used for storing the computer program and other programs and data required by the arbitrary data processing-capable device, and may also be used for temporarily storing data that has been output or is to be output.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (4)
1. A variable speed limit and ramp current limiting cooperative control method for a highway confluence area is characterized by comprising the following steps:
the method comprises the following steps: coding and dividing the express way, and installing equipment;
the first step is specifically as follows:
(1.1) carrying out coding division on the express way: the express way is divided into four parts: a variable speed-limiting area V, an accelerating area A, a confluence area M and a ramp area R; the variable speed-limiting area V is an upstream section of the main road of the express way, the main road of the express way is an intermediate section of the main road of the express way, the confluence area M is a downstream section of the main road of the express way, and the ramp area R is a ramp of the express way;
(1.2) arranging a coil detector on each lane of the variable speed-limiting area V, wherein the coil detector is used for acquiring real-time traffic flow data of the variable speed-limiting area V; arranging a variable speed limit information board at the starting point of each lane of the variable speed limit area V, wherein the variable speed limit information board is used for issuing a variable speed limit instruction and is arranged on a traffic portal frame; laying a coil detector on each lane of the confluence area M for acquiring real-time traffic flow data of the confluence area M; arranging a coil detector on each lane of the ramp region R for acquiring real-time traffic flow data of the ramp region R; arranging a ramp current-limiting signal device at the end point of each lane of the ramp region R, and adjusting a signal lamp to achieve the aim of ramp current limiting;
step two: data collection and analysis are carried out depending on the installed equipment, and lane-level traffic flow indexes of different areas of the express way are obtained according to the codes of the express way in the step one;
the second step is specifically as follows:
(2.1) acquiring lane-level traffic flow indexes according to traffic flow data of the variable speed-limiting area V, wherein the lane-level traffic flow indexes comprise traffic flow density and traffic flow, and calculating to obtain saturated flow Q of the variable speed-limiting area V v Traffic flow speed w v Free flow velocity u v Density of congestion k v_j Critical density k v_c Constructing a triangular traffic flow basic diagram of the variable speed limit area V under a normal state; and obtaining the optimal occupancy o of the variable speed limit area V v_c ，
；
(2.2) acquiring a lane-level traffic flow index according to the traffic flow data of the confluence area M, and calculating to obtain the saturated flow Q of the confluence area M m Traffic flow speed w m Free flow velocity u m Density of congestion k m_j Critical density k m_c Constructing a triangle traffic flow basic diagram of the confluence area M under a normal state; and obtaining the optimal occupancy rate o of the confluence region M m_c ，
；
(2.3) obtaining a lane-level traffic flow index according to the traffic flow data of the ramp area R, and calculating to obtain the saturated flow Q of the ramp area R r Traffic flow speed w r Free flow velocity u r Density of congestion k r_j Critical density k r_c Constructing a triangular traffic flow basic diagram of the ramp region R under a normal state; and the optimal occupancy rate o of the ramp area R is obtained r_c ，
；
Step three: performing variable speed limit and ramp current limit cooperative control according to lane-level traffic flow indexes of different areas of the express way;
the third step is specifically as follows:
(3.1) every T seconds as a control cycle length;
(3.2) before the current control period starts, judging to adopt a ramp current-limiting control strategy or a variable speed-limiting control strategy:
if the actual traffic occupancy of the ramp region R in the previous control period is greater than a% of the preset traffic occupancy, a variable speed limit control strategy is adopted in the current whole control period;
if the actual traffic occupancy of the ramp region R in the previous control period is less than a% of the preset traffic occupancy, adopting a ramp current-limiting control strategy in the current whole control period;
(3.3) after the current control period is finished, returning to the step (3.2) and entering a new control period;
the variable speed limit control strategy specifically comprises the following steps:
a1) in the current whole control period, ramp current-limiting signal equipment arranged at the end point of a ramp region R always displays green light;
a2) the speed limit value displayed by the speed limit changing information board of the main road lane of the express way which is not closest to the ramp is as follows:
if the average occupancy of the variable speed-limit zone V in the previous control period is less than
Wherein, in the step (A),
if so, in the current whole control period, the variable speed limit information board of the lane displays the original speed limit value of the main road of the express way;
if the average occupancy of the variable speed-limiting region V in the previous control period is larger than
If the speed limit value displayed by the variable speed limit information board of the lane is v in the current whole control period vsl ，
；
a3) The speed limit value displayed by the speed limit changing information board of the main road lane of the express way closest to the ramp is as follows:
if the average occupancy of the lane in the previous control period is less than
Wherein n is the number of lanes of the main road of the express way, and the variable speed limit information board of the lanes displays the original speed limit value of the main road of the express way in the current whole control period;
if the average occupancy of the lane in the last control cycle is larger than
If the speed limit value displayed by the variable speed limit information board of the lane is v in the current whole control period vsl-s ，
。
2. The method for the cooperative control of the variable speed limit and the ramp current limit of the expressway merge area according to claim 1, wherein the ramp current limit control strategy specifically comprises:
b1) in the current whole control period, the variable speed limit information boards of all lanes of the main road of the express way display the original speed limit value of the main road of the express way;
b2) obtaining the average occupancy rate o of the confluence region M of the previous control period m And the current limiting value of ramp region R
Calculating the current limiting value of the ramp region R in the current control period as R,
wherein, K is R The flow convergence range is adjustable parameters, the value range is 45-80, and the flow convergence range can be flexibly adjusted according to the length of the flow convergence region M and the habit of local drivers;
b3) corresponding the ramp region R current limiting value R in the current whole control period to the traffic light duration of the ramp current limiting signal equipment;
if the current limiting value R is smaller than the saturated flow Q of the ramp region R r Then the ramp current-limiting signal equipment always displays green light in the whole control period;
if the current limiting value R is larger than the saturated flow Q of the ramp region R r And the time of the ramp current-limiting signal device displaying green light in the whole control period is T r/Q r And the rest of the time shows a red light.
3. A device for cooperatively controlling the variable speed limit and the ramp current limit of a highway confluence region, which is characterized by comprising one or more processors and is used for realizing the method for cooperatively controlling the variable speed limit and the ramp current limit of the highway confluence region according to any one of claims 1-2.
4. A computer-readable storage medium having a program stored thereon, wherein the program, when executed by a processor, is configured to implement the method for cooperative control of variable speed limit at an express merge region and ramp flow restriction of any one of claims 1-2.
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