JP2009042894A - Control unit and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control unit, in which a traffic condition under following and an offset influence are taken into consideration in offset following. <P>SOLUTION: An offset-sub area tree generation unit 10 controls an offset indicative of a difference of green start time points between neighboring traffic signals 5. A link coupling the neighboring traffic signals is searched (16), and based on the offset information, a plurality of offset candidates in the above link are generated within a predetermined area (17). Then, a plurality of delay time periods in the link are calculated (18), and the offset candidate having the minimum delay time period among the plurality of delay time periods is selected as a new offset (19). An appropriate offset is set thereby. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device and a control method, and more particularly to a control device and a control method for obtaining an offset that is a difference in blue start time of a signal and a sub-area tree that is a tree-like path for propagating the offset.

  In recent years, the problem of traffic congestion due to automobiles has become prominent, and there is a further demand for efficient use of roads. As a method of using the road efficiently, individual control is performed independently, and independent control without considering the influence of other signals, system control for controlling a signal group on the same road or road network, and the like are performed.

  In system control, the split that indicates the ratio of green signal time that the signal gives to traffic flow in each direction, the offset that indicates the difference in green signal start time between adjacent signals, and the cycle length that indicates the cycle of the signal are adjusted. ing.

  As an example of a system control method, in online / real-time signal control, a method is known in which a target value is given at a control cycle such as an offset of 5 or 15 minutes, and the value is changed accordingly (for example, non-patent). Reference 1). At this time, an adjustment amount that can be changed by one change is determined, and when the target value exceeds this, a process called offset follow-up that performs stepwise adjustment over a plurality of cycles is performed. Further, the direction and order in which the offset is given to the adjacent node (intersection) is determined by a link set in advance based on the result of traffic survey or the like.

  Hereinafter, a minimum unit area constituted by the links is referred to as a subarea, and a set of links formed by combining one or more subareas is referred to as a subarea tree. Within the sub-area, the traffic lights are operated with the same period.

  As another example of the system control method, the change direction of the offset is divided into plus (cycle length is gradually increased) and minus (cycle length is gradually reduced), and the number of follow-ups to the target offset A method is known in which the number of inversions in the process is minimized and a combination of the following directions is obtained by reducing to linear programming (see, for example, Patent Document 1).

  In addition, as another example of the system control method, the evaluation value when the two adjacent subareas are system controlled with their respective cycle lengths is compared with the evaluation value when combined with the longer cycle length, and the evaluation value is small As a reasonably good method, a method of combining if the evaluation value when combined is small is known (for example, see Patent Document 2).

FIG. 14 is a conceptual diagram of conventional offset tracking, in which the relationship between the time and the cumulative number of arriving vehicles in the conventional offset tracking process (see FIG. 14A), and the relationship between the offset and the delay time (FIG. 14B). Reference). i is the number of offset changes accompanying tracking, and when tracking occurs, the offset is increased (plus tracking) or decreased (minus tracking) by the tracking width ΔO _s toward the target value. FIG. 14 shows the cumulative number in the case of following twice from the state before tracking (i = 0). The area of this cumulative number corresponds to the total stop time of the arrival vehicle, that is, the delay time PI.

The control parameters include cycle C (signal period), split S (ratio of green signal time that signal gives to traffic flow in each direction), and offset O (difference in green signal start time between adjacent signals). When C and S are fixed and the relationship between PI and O is simplified as PI _i = f (O _i ), the value that PI _{i + 1} after the offset change can take is f (O _i + ΔO _s ) or f (O _i − ΔO _s ).

“Guidelines for revised traffic signals”, Traffic Engineering Research Association, July 2006, p. 57-60 JP 2000-259985 A JP 2000-20882 A

However, in the offset tracking shown in FIG. 14, the value of PI _{i + 1} after the offset change is determined by the tracking width and the tracking direction, and thus is not necessarily smaller than PI ₀ before tracking.

  Further, in the method of Non-Patent Document 1, the offset in the follow-up process is transient. For this reason, the intended offset is not operated until the tracking is stopped, and there is a possibility that the traffic flow is hindered. In addition, system control is performed between the combined subareas, but the determination of the connection is made based only on the cycle length. The influence of the given offset is not considered, and an appropriate offset is not necessarily set.

  Moreover, in the method of Patent Document 1, the offset is changed so that the tracking is completed as soon as possible, but the traffic situation during the tracking is not taken into consideration. Even during tracking, it is desirable to appropriately control the offset by some means.

  Further, in the method of Patent Document 2, a combination is determined based on an evaluation value and a sub-area tree is configured. However, it is not possible to change a direction in which an offset is applied or a node to be combined. The traffic situation is constantly changing, and it is desirable to give an arbitrary direction and an offset with the other party in order to perform system control suitable for the flow of the vehicle group.

  The present invention has been made in view of the above-described conventional circumstances, and it is an object of the present invention to provide a control device and a control method that take into account the influence of traffic conditions and offset during tracking in offset tracking.

  In order to achieve the above object, a first control device of the present invention is a control device that controls an offset indicating a time difference of blue start between adjacent traffic signals, and searches for a link that connects the adjacent traffic signals. A target link search unit, an offset candidate generation unit that generates a plurality of offset candidates in the link in a predetermined range based on offset information related to the offset, a traffic situation in the link and the offset candidate, A delay time calculation unit that calculates a plurality of delay times corresponding to the stop time of the entire vehicle on the link, and an offset selection unit that selects, as a new offset, an offset candidate for which the minimum delay time is calculated among the plurality of delay times. It has the composition to have.

  According to the above configuration, since the offset is changed while reproducing the actual traffic flow, it is possible to obtain the offset in consideration of the influence of the propagation process on the traffic situation. In addition, since the offset is adjusted within an arbitrary adjustment range, there is no need to provide a step-wise offset toward the target value, and an offset that minimizes the delay time within a followable range can be obtained.

  In addition, the second control device of the present invention includes a sub-area tree generation unit that generates a sub-area tree that is a tree-like path that couples a link corresponding to the new offset and propagates the new offset. It is configured.

  According to the above configuration, it is possible to generate a sub-area tree that can perform optimal signal control with a minimum delay time in each link.

  Further, in the third control device of the present invention, when the sub-area tree generation unit has adjacent sub-areas indicating regions in which the traffic signal is operated in the same cycle, and the difference in cycle length is within a predetermined range, One subarea tree is generated including links existing between subareas.

  According to the said structure, when the subareas of the same period satisfy | fill predetermined conditions, it is possible to produce | generate as one subarea tree.

  The first control method of the present invention is a control method for controlling an offset indicating a time difference of blue start between adjacent traffic signals, wherein the control device searches for a link connecting the adjacent traffic signals. And a step of generating a plurality of offset candidates in the link in a predetermined range based on the offset information related to the offset, and a stop time of the entire vehicle in the link based on the traffic situation in the link and the offset candidate. The method includes a step of calculating a plurality of corresponding delay times and a step of selecting, as a new offset, an offset candidate for which the minimum delay time has been calculated among the plurality of delay times.

  According to the above method, since the offset is changed while reproducing the actual traffic flow, it is possible to obtain an offset considering the influence of the propagation process on the traffic situation. In addition, since the offset is adjusted within an arbitrary adjustment range, there is no need to provide a step-wise offset toward the target value, and an offset that minimizes the delay time within a followable range can be obtained.

  In addition, the second control method of the present invention includes a sub-area tree generation step of generating a sub-area tree that is a tree-like route for combining the link corresponding to the new offset and propagating the new offset. It's a way.

  According to the above method, it is possible to generate a sub-area tree that can perform optimal signal control with a minimum delay time in each link.

  Further, in the third control method of the present invention, in the sub-area tree generation step, when the sub-areas indicating areas where the traffic lights are operated in the same cycle are adjacent to each other, and the difference in cycle length is within a predetermined range, This is a method for generating one subarea tree including links existing between subareas.

  According to the above method, when the subareas having the same period satisfy a predetermined condition, the traffic signal can be generated as one subarea tree.

  As described above, according to the present invention, the offset is changed while reproducing the traffic flow according to the sub-area tree, so that an offset considering the influence of the propagation process on the traffic situation can be obtained.

  In addition, since the offset is adjusted in an arbitrary adjustment range in the propagation process, there is no need to provide a stepwise offset toward the target value, and an offset that minimizes the delay time can be obtained in a followable range.

  In addition, since links are searched to minimize the delay time and sub-area trees are constructed, the appropriate link direction and the presence / absence of coupling are set according to traffic conditions without conducting traffic surveys, etc. be able to.

  Moreover, a subarea tree and an offset for arbitrary traffic flow data are generated using a traffic flow simulation. For this reason, it is possible to dynamically change the sub-area tree and offset in response to changes in traffic conditions.

  Hereinafter, an offset subarea tree generation apparatus and method according to an embodiment of the present invention will be described with reference to the drawings. First, the concept of offset tracking in this embodiment will be described.

  FIG. 13 is a diagram showing an outline of an example of offset tracking in the embodiment of the present invention. In the course of the offset tracking operation, an offset that minimizes the delay time within a changeable range is obtained.

In FIG. 13, i indicates the number of offset changes accompanying tracking. Further, in the graph composed of the cumulative number axis and the time axis in FIG. 13A, the triangular area (PI ₀ , PI ₁ , PI ₂ ) corresponds to the total stop time of the arrival vehicle, that is, the delay time PI. Here, the case of i = 0, 1, and 2 is illustrated.

Within the tracking width ΔO _s from the offset O _{i, the} changeable range (O _i −ΔO _{s to} O _i + ΔO _s ) is set, and a plurality of offset compensations are generated. The bar bluff in FIG. 13B represents the delay time PI for each compensation. Among them, the offset change amount ΔO _i that is the minimum delay time is adopted, and the offset (O _{i + 1} = O _i + ΔO _i ) in the follow-up process is determined. Here, the case of i = 0, 1 is illustrated.

  Next, an example of the configuration of the road system 100 for performing offset tracking as described above will be described.

  FIG. 1 is a block diagram illustrating an example of a schematic configuration of a road system 100 according to an embodiment of the present invention. The road system 100 includes a road network 1, a signal control device 7, and an offset / subarea tree generation device 10. The offset / subarea tree generation device 10 is an example of a “control device”.

  In the road network 1, an intersection (node) 2 and a road 3 are schematics of the intersection and the road, respectively. The sub-area 4 is an area that includes a plurality of nodes and operates them with the same cycle length. A traffic light 5 is installed at an intersection 2 in the road network 1 to control traffic. The sensor 6 is installed on the road 3 and can measure the cross-sectional traffic volume, occupation rate, and speed of the vehicle by a method such as ultrasonic waves, microwaves, optics, and loop coils.

  The signal control device 7 is a device that can control the traffic lights 5 and the like on the road network 1 and collects traffic information and generates signal control parameters on-line and in real time. The signal control device 7 includes a sensor information measurement unit 8 and a signal control information calculation unit 9.

  The sensor information measuring unit 8 totals sensor information including the traffic volume and speed measured by the sensor 6 every 5 minutes or 2.5 minutes.

  The signal control information calculation unit 9 generates a parameter selected from a pattern set for each time zone and day-of-week attribute or a signal control parameter generated based on the sensor information of the sensor information measurement unit 8 in each road network 1. Send to traffic light. Here, the cycle length (signal period) and split (ratio of the green signal time that the signal gives to the traffic flow in each direction), which are signal control parameters, are calculated by the existing method, and the offset (green signal start time between adjacent signals) Only) is calculated by the method of this embodiment.

  The offset / subarea tree generation device 10 is connected to the signal control device 7 by communication means (not shown) and can transmit and receive data to and from each other. The offset / sub-area tree generation device 10 includes a target link search / search unit 16, an offset candidate generation unit 17, a delay time calculation unit 18, an offset selection unit 19, a sub-area tree generation unit 20, and a memory 30. .

  The memory 30 includes link information storage means 11, current parameter storage means 12, traffic flow data storage means 13, generated offset storage means 14, and tree information storage means 15, and includes link information, tree information, and various other information. Remember.

  The link information accumulating unit 11 manages link information indicating a direction in which an offset is given between the intersections 2.

  The current parameter storage unit 12 stores the control parameter calculated by the signal control information calculation unit 9.

  The traffic flow data storage means 13 stores the traffic flow data including the traffic volume and the speed collected by the sensor information measuring unit 8. Here, it is assumed that time-series traffic flow data is received by a communication means (not shown) at a control cycle or at an arbitrary timing and stored in the traffic flow data storage means 13.

  The generated offset accumulation unit 14 stores generated offset information of each link. A link is a combination of adjacent intersections 2. The offset information includes information on the offset selected by the offset selection means 19.

  The tree information storage unit 15 holds tree information indicating the coupling relationship of the generated sub-area trees. A sub-area tree is a set of links formed by connecting one or more sub-areas 4.

  The target link search unit 16, the offset compensation generation unit 17, the delay time calculation unit 18, the offset selection unit 19, and the subarea tree generation unit 20 generate an offset adjustment amount for each link of the road network 1, and the signal control device 7 to send.

  The target link search unit 16 searches and extracts a link capable of transmitting an offset based on information held by the link information storage unit 11 for an arbitrary link.

  The offset compensation generation unit 17 generates a new offset within a range adjustable from the current offset for the link extracted by the current parameter storage unit 12.

  The delay time calculation means 18 acquires the traffic volume and speed of the link from the traffic flow data accumulation means 13, and estimates a vehicle group that starts from the upstream intersection and reaches the downstream side with diffusion. Further, the delay time is calculated from the stop time and the number of stops of the vehicle arriving downstream.

  The offset selection means 19 compares the delay times for the respective offsets calculated by the delay time calculation means 18 and selects an offset having a smaller delay time.

  The subarea tree generation means 20 adds the link given the offset selected by the offset selection means 19 to the subarea tree.

  Next, an example of a subarea configuration in the road network 1 will be described. FIG. 2A is a diagram showing an example of a subarea configuration in the road network 1.

The sub-area 202 includes a key node 203 serving as the root of the tree and a general intersection 204 other than the key node 203 and is connected to each other via a link 205. Each intersection is given a unique identification symbol (A to K in the figure), and a link having a connection relationship is expressed as a symbol string of a start / end node such as AB or AC. All elements representing the connection relationship are stored in the list L _ALL . The list L _ALL can be expressed as follows.

L _ALL = {AB, AC, BD, BE, CD, CJ,..., GI}

Also, L _GET and L _SET are set as a subset of L _ALL , the link to be searched is stored in L _GET , and the offset-set link is stored in L _SET . L _GET , L _SET , and L _ALL are stored in the memory 30. Note that L _GET , L _SET , and L _ALL satisfy the following relationship.

L _SET ⊆L _ALL
L _GET ⊆L _ALL

  FIG. 2B is a diagram illustrating a configuration example of the sub-area tree. Such a configuration is obtained by, for example, linking nodes B, C connected to node A, and nodes D, E... Other than node A connected to node B in a tree shape starting from key node A 203. Created. Tree information is referred to in the generation of sub-area trees.

  Next, an example of the operation of the offset / subarea tree generation device 10 will be described. FIG. 3 is a flowchart showing an example of the overall processing flow of the offset / subarea tree generation device 10.

First, the target link search means 16 performs a process (step S301). Mainly, a link extracted by searching for a link capable of transmitting an offset is added to the list L _GET .

Subsequently, the offset compensation generating means 17 performs processing (step S302). Mainly, the offset compensation of each link is obtained for the end node of each link stored in L _GET .

  Subsequently, the delay time calculation means 18 performs processing (step S303). Mainly, the traffic flow is reproduced based on the sensor data and the generated offset compensation, and the delay time is calculated.

Subsequently, the offset selection means 19 performs processing (step S304). Mainly, the node with the smallest delay time in L _GET and the offset compensation pair are extracted, and the offset is set. Then, the set link is _removed from the L _GET and added to the set link list L _SET .

  Subsequently, a control unit (not shown) determines whether or not an unsearched link exists (step S305). If it exists, the process returns immediately before step S301. If it does not exist, the subarea tree generation means 20 performs processing (step S306). Mainly, tree configuration information is obtained.

Next, the target link search means 16 will be described.
FIG. 4 is a flowchart showing an example of the operation of the target link search means 16. 5 to 7 are conceptual diagrams of an example of search by the target link search means 16.

First, a list L _ALL containing all link information and a list L _SET containing link information of offset-set links are called from the memory 30 (step S401).

Subsequently, it is determined whether or not the search target link list L _GET is empty (step S402). If it is empty, the link starting from the root of the tree (corresponding to the key node 203 of A in FIG. 2) is stored in L _GET and the process is terminated (see FIG. 5) (step S403).

  If it is not empty, it searches for a link that has a connection relationship with the set link, the offset is not set, and does not become a closed loop (step S404), and determines whether such a link exists (step S405).

If there is a link that satisfies the condition, it is added to L _GET and the process is terminated (see FIGS. 6A and 6B) (step S406). If there is no link, an empty set is set for L _GET. The process ends (see FIG. 7) (step S407).

  Next, the offset generation means 17 will be described. FIG. 8 is a flowchart showing an example of the operation of the offset candidate generation means 17.

First, an element is extracted from the head of the unset link list L _GET and a terminal node symbol i is extracted (step S801).

Subsequently, the offset current value O _i of the node i (= 1, 2,..., N) is obtained from the current parameter storage unit 12 (step S802). Subsequently, M offset compensations O _ij (j = 1, 2,..., M) are generated in an arbitrary range based on the current value O _i (step S803) and stored in the memory 30. The process ends (step S804). Note that the above-mentioned arbitrary range can be set by the offset candidate generating means 17.

  Next, the delay time calculation means 18 will be described. FIG. 9 is a flowchart showing an example of the operation of the delay time calculation means 18.

First, read the offset candidate _{O ij} of starting node from the memory 30 (step S901), it reads the traffic and velocity data of the link from the traffic flow data storage unit 13 (step S902).

Then, based on the offset Hoho O _ij and traffic flow data to generate time-series data of the vehicle group traveling on the link (vehicle group profile) (step S903). Based on the vehicle group profile and the parameters of the downstream intersection, the stop count S and the stop time D are calculated (step S904). The delay time PI _ij which is a value obtained by weighted combination of these is stored in the memory 30 (step S905).

  Next, the offset selection means 19 will be described. FIG. 10 is a flowchart showing an example of the operation of the offset selection means 19.

First, the target link L _GET , the offset compensation O _ij , and the delay time PI _ij are read from the memory 30 (step S1001).

Subsequently, the combination of the offset and the link with the smallest delay time is extracted (step S1002). The extracted link is added to the searched list L _SET (step S1003), the extracted offset is accumulated in the offset accumulating means 14, and the process is terminated (step S1004).

  Next, the sub area tree generation means 20 will be described. FIG. 11 is a flowchart showing an example of the operation of the subarea tree generation means 20.

First, a list L _SET of searched links is read from the memory 30 (step S1101). The element (link) is taken out from the head of the list L _SET (step S1102), and the connection relation of the start / end nodes is added to the tree information (step S1103).

Subsequently, it is determined whether or not L _SET is empty (step S1104). If not empty, the process returns to immediately before S1102. If it is empty, the tree information indicating the obtained connection relationship is stored in the tree information storage means 15 and the process ends (S1105).

  For example, when the searched list of FIG. 7 is obtained by the search, the generated subarea 1201 indicating the shape of the generated subarea tree is as shown in FIG. FIG. 12 is a diagram illustrating an example of the shape of the sub-area tree generated by the offset / sub-area tree generation apparatus 10.

  When generating a sub-area tree, if sub-areas 4 having a predetermined cycle length difference are adjacent to each other, one sub-area tree is configured including links existing between the sub-areas. Tree information is generated.

  According to such a road system 100, it is possible to set the offset, which is the difference in the blue start time of the signal, so that the delay time of the propagation process becomes small. Therefore, if this offset is applied to a traffic control system, a smooth traffic flow can be obtained even during tracking.

  Further, a link that gives an offset between intersections can be searched to generate a sub-area tree that is a tree-like route. Therefore, it is possible to provide the traffic control system with the link direction and the connection destination according to the traffic situation.

  INDUSTRIAL APPLICABILITY The present invention is useful as a control device, a control method, a traffic control system, and the like in consideration of the influence of traffic conditions and offset during tracking in offset tracking.

The figure which shows an example of the system configuration | structure in embodiment of this invention The conceptual diagram which shows an example of the subarea structure in embodiment of this invention The flowchart which shows an example of operation | movement of the offset subarea tree generation apparatus in embodiment of this invention. The flowchart which shows an example of operation | movement of the object link search means in embodiment of this invention. The conceptual diagram which shows an example of the search by the object link search means in embodiment of this invention The conceptual diagram which shows an example of the search by the object link search means in embodiment of this invention The conceptual diagram which shows an example of the search by the object link search means in embodiment of this invention The flowchart which shows an example of operation | movement of the offset compensation production | generation means in embodiment of this invention. The flowchart which shows an example of operation | movement of the delay time calculation means in embodiment of this invention. The flowchart which shows an example of operation | movement of the offset selection means in embodiment of this invention. The flowchart which shows an example of operation | movement of the subarea tree production | generation means in embodiment of this invention. The conceptual diagram which shows an example of the subarea tree produced | generated by the subarea tree production | generation means in embodiment of this invention The conceptual diagram which shows an example of the offset tracking in embodiment of this invention Conceptual diagram of conventional offset tracking

Explanation of symbols

100 Road system 1,201 Road network 2 Intersection (node)
3 Road 4, 202 Subarea 5 Traffic light 6 Sensor 7 Signal controller 8 Sensor information meter side 9 Signal control information calculator 10 Offset / subarea tree generator 11 Link information storage means 12 Current parameter storage means 13 Traffic flow Data storage means 14 Generated offset storage means 15 Tree information storage means 16 Target link search means 17 Offset compensation generation means 18 Delay time calculation means 19 Link / offset selection means 20 Sub-area tree generation means 203 Key node 204 General node 205 Link 206 Graph 1201 Generation subarea

Claims (6)

A control device for controlling an offset indicating a time difference of blue start between adjacent traffic lights,
A target link search unit for searching for a link connecting the adjacent traffic signals;
An offset candidate generating unit that generates a plurality of offset candidates in the link in a predetermined range based on the offset information regarding the offset;
A delay time calculation unit that calculates a plurality of delay times corresponding to the stop time of the entire vehicle in the link based on the traffic situation in the link and the offset candidate;
A control device comprising: an offset selection unit that selects, as a new offset, an offset candidate for which a minimum delay time has been calculated among a plurality of delay times. The control device according to claim 1, further comprising:
A control apparatus comprising: a sub-area tree generation unit that generates a sub-area tree that is a tree-like path that couples a link corresponding to the new offset and propagates the new offset. The control device according to claim 2,
The sub-area tree generation unit includes one sub-area including a link existing between sub-areas when sub-areas indicating areas in which the traffic signals are operated in the same cycle are adjacent to each other and the difference in cycle length is within a predetermined range. A controller that generates subarea trees. A control method for controlling an offset indicating a time difference of blue start between adjacent traffic lights,
In the control device,
Searching for a link connecting the adjacent traffic lights;
Generating a plurality of offset candidates in the link in a predetermined range based on offset information related to the offset;
Calculating a plurality of delay times corresponding to the stop time of the entire vehicle on the link based on the traffic situation on the link and the offset candidates;
And a step of selecting, as a new offset, an offset candidate for which a minimum delay time has been calculated among a plurality of delay times. The control method according to claim 4, further comprising:
A control method comprising a sub-area tree generation step of generating a sub-area tree that is a tree-like path for combining the links corresponding to the new offset and propagating the new offset. The control method according to claim 5, comprising:
In the sub-area tree generation step, when sub-areas indicating areas where the traffic signals are operated in the same cycle are adjacent to each other and the difference in cycle length is within a predetermined range, one link including the links existing between the sub-areas is included. A control method that generates subarea trees.