JP2003217085A - Dispersive signal control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersive signal control system for automatically determining so that an individual cycle, a split, and an offset become optimal while respective signal controllers are cooperating with a signal controller of an adjacent crossing without predetermining a range having a common cycle. <P>SOLUTION: This dispersive signal control system can exchange information with the signal controller of the adjacent crossing by connecting the signal controllers 2<SB>1</SB>to 2<SB>6</SB>of respective crossings 1<SB>1</SB>and 1<SB>6</SB>by a telecommunication line. The individual signal controller measures a traffic flow rate of respective inflow passages flowing in the crossing of itself, and calculates the cycle and the split minimally required at the crossing of itself on the basis of the traffic flow rate. The information is exchanged with the adjacent crossing via the telecommunication line to determine whether the cycle is adjusted or not adjusted by a predetermined evaluation function. An optimal offset is also calculated when adjusting the cycle. The cycle is adjusted to a present traffic state after transferring to a desired value with these cycle, split, and offset as the desired value, and the split and the offset can be adjusted and changed in a predetermined range. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal control system in which a signal controller at each intersection cooperates with each signal controller at an adjacent intersection to automatically determine individual cycle lengths, splits, and offsets. .

[0002]

2. Description of the Related Art Optimization of traffic signal control parameters is
It is important for smooth road traffic. There are three control parameters: cycle length, split, and offset. The cycle length is a display period of signal display, and indicates the time taken for the signal display to make one round from the east-west direction to the north-south direction.
If the traffic volume becomes large, unbalanced parts will occur unless the cycle length is made large, which causes traffic congestion. On the contrary, if the cycle length is too large, the dead time zone in which the vehicle does not pass increases, and the delay time also increases.

Split is the ratio of green time to the cycle length. The split also increases the dead time and the delay time unless an appropriate green time is given for each direction. The offset is the deviation of the blue display start timing between adjacent intersections.In order to avoid waiting and unnecessary green time at the intersections, the offset is adjusted to the running time of the vehicle and the green time of each intersection is changed in order. By turning on the lights, it is possible to obtain the effect of smoothly flowing traffic. If the time setting of the offset and the direction to be taken do not comply with the traffic situation, not only will the effect of the offset not be effective, but on the contrary, it will obstruct the flow of traffic and cause a large delay time. The purpose of the signal control system is to optimize these three control parameters and reduce the vehicle delay time.

As one of the signal control systems, all the signal controllers in the control area and all the sensors for measuring the traffic volume are connected to the central unit, and the central unit is operated based on the measured traffic volume. There is a method of determining and instructing control parameters of each controller.

In this method, in calculating the control parameters, the entire control area is first divided in advance into a small range having a connection as a traffic flow. The divided area is called a sub-area, and the sub-area operates with a common cycle length. The common cycle length is generally obtained based on the amount of alternating current at a preselected important intersection. As the important intersections, intersections that are assumed to have a high traffic volume such as national roads are selected. The split was conventionally determined based on the result of the traffic volume survey by hand, but in recent years, it has come to be automatically calculated from the traffic volume measurement result. Focusing on the main routes in the sub-area, the offset is used by switching several patterns according to the traffic volume. For example, a pattern with an offset from east to west is used in a time zone with a large amount of traffic toward the west, and a pattern with an offset from west to east is used in a time zone with a large amount of traffic toward the east. Similar to split, in recent years, studies have been made to automatically generate an offset pattern based on traffic volume measurement results.

According to the above method of applying the common cycle length in the sub-area, the cycle length obtained at the important intersection is applied although the traffic volume is small at the intersections other than the important intersection. For this reason, a green time is wasted and a delay time occurs. Further, the offset pattern created by focusing on the main route, the sub-area selected in advance, and the important intersection cannot be said to be consistent with the actual traffic situation every moment. It is also necessary to revisit according to the change of stores on the route and the holding of events.

Even in the above-mentioned method in which the central unit executes control, it is possible to automatically select sub-areas and important intersections according to traffic conditions and automatically calculate control parameters, but the number of signal controllers to control increases. Therefore, the calculation of the central device becomes huge and complicated, which is difficult in reality.

As another signal control system, a distributed signal control system in which each signal controller individually executes control is being considered. However, it is difficult to stably and optimally control the entire control area by controlling each signal controller in such a distributed system, and an appropriate method has not been proposed at present. In many cases, the central device is the main control unit, and the control executed by the signal controller at each intersection is often limited to adjusting the control parameters determined by the central device according to the traffic conditions at the intersection.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to communicate with each signal controller of an adjacent intersection without having a large-scale central device and to respond to a change in traffic conditions. Is to provide a distributed signal control system that automatically calculates and controls individual cycle lengths, splits, and offsets.

Another object of the present invention is to automatically calculate control parameters according to changes in traffic conditions, thereby significantly reducing operation costs and maintenance costs for calculating and reviewing control parameters. To provide.

Another object of the present invention is to provide an extreme value of a plurality of optimum points that appears when determining optimum control parameters existing in existing signal control systems regardless of whether they are centralized or distributed. It is to provide a control algorithm that selects a true optimum point without falling.

[0012]

[Means for Solving the Problems] Means for solving the problems will be described below with reference to the numbers and symbols used in the embodiments of the present invention. These numbers and symbols are added to clarify the correspondence between the description in [Claims] and the description in [Embodiment of the Invention]. However, the added numbers / codes should not be used for the interpretation of the technical scope of the invention described in [Claims].

[0013] Distributed signal control system according to the invention, a plurality of intersections ₍₁ 1 to 1 ₆₎ a plurality of signal controllers provided in each of the ₍₂ 1 to 2 _6), the intersection ₍₁ 1 to 1
Each traffic flow measuring the measuring means _{6) (4} 1 -
4 ₄ ) and. Each of the signal controllers (2 _{1 to} 2 ₆ ) is based on the traffic flow rate of its own intersection and the information sent from the adjacent intersection signal controller provided at the adjacent intersection adjacent to the own intersection. hand,
Determine the cycle length of the self intersection, the split, and the offset between the self intersection and the adjacent intersection.

Each of the signal controllers (2 ₁ to 2 ₆ ) calculates (a) a time average value which is an average value of the traffic flow rate of the link from the adjacent intersection to the own intersection in a predetermined period, Using the distance from the adjacent intersection to the own intersection and the time average value, a cycle length target value of the own intersection, a split target value, and an offset target value between the own intersection and the adjacent intersection. And (b) the cycle length, the split, and the offset are set so that the cycle length target value, the split target value, and the offset target value are gradually approached, respectively. Now, it is preferable to execute the step of adjusting the split and the offset.

Each of the signal controllers (2 ₁ to 2 ₆ ) is
When the cycle length target value of the own intersection and the cycle length target value of the adjacent intersection determined by the adjacent intersection signal controller match, the cycle length target value of the adjacent intersections that match. Among them, the one with the maximum traffic flow to the own intersection is defined as an offset cooperative intersection, and, based on the cycle length target value of the offset cooperative intersection and the split target value, the offset target value of the own intersection. Is preferably determined.

The cycle length target value determined by each of the signal controllers (2 ₁ to 2 ₆ ) is preferably discretized at predetermined intervals.

Each of the signal controllers (2 ₁ to 2 ₆ ) is
(C) A first delay time that a vehicle traveling from the adjacent intersection having the same cycle length target value to the own intersection waits at the own intersection, and a vehicle traveling from the own intersection to the adjacent intersection has the target. A step of expressing a total delay time, which is the sum of the second delay times waited at the adjacent intersections having the same cycle length, as a function of δ ₁ and δ ₂ defined below, and δ ₁ = {(L / V) mod C} -O ₁ , δ ₂ = {(L / V) mod C} -O ₂ , L: distance between the adjacent intersection and the own intersection V: predetermined speed C: the own intersection and the adjacent said cycle length target value coincides with the intersection O _1: said adjacent said viewed from the intersection the offset target value of the self intersection O _2: wherein the offset target value of the adjacent intersection as viewed from the self intersection; (d) δ And determining a constraint condition for the [delta] _2, calculating the (e) satisfy the constraints, and to minimize the total delay time [delta] ₁ and [delta] _2,
(F) The step of calculating the offset target value based on δ ₁ and δ ₂ that minimizes the total delay time is preferably executed.

Each of the signal controllers (2 ₁ to 2 ₆ ) is
Using the distance from the adjacent intersection to the own intersection and the time average value, to determine the provisional cycle length target value of the own intersection, and, and the provisional cycle length target value of the own intersection, When the provisional cycle length target value of the adjacent intersection does not match, the cycle length target value of the own intersection is set to the provisional cycle length target value of the own intersection and the provisional cycle length of the adjacent intersection. It is preferable that the target value and the target intersection are determined so that the delay time generated at the own intersection and / or the adjacent intersection becomes smaller.

Each of the signal controllers (2 ₁ to 2 ₆ ) is
It is preferable that the time average value is calculated as a function value of a time average value calculation function that is a function of an actual measurement value of a traffic flow rate of a vehicle flowing into the adjacent intersection from a link other than a link connecting to the own intersection.

Each of the signal controllers (2 ₁ to 2 ₆ ) is
It is preferable that the function parameter of the time average value calculation function is modified so that the error between the time average value of the actually measured traffic flow rate of the inflow link and the function value becomes small.

Each of the signal controllers (2 ₁ to 2 ₆ ) is
(G) After the cycle length, the split, and the offset substantially match the cycle length target value, the split target value, and the offset target value, respectively, the split and the offset It is preferable to execute the step of adjusting and changing the values and within the predetermined range by using the time average value.

[0022]

DETAILED DESCRIPTION OF THE INVENTION Referring to the accompanying drawings,
An embodiment of the distributed signal control system according to the present invention will be described.

In one embodiment of the distributed signal control system according to the present invention, as shown in FIG. 1, the signal controller 2A is provided at each of the intersections 1A to 1F which are control targets.
~ 2F is provided. The intersections 1A to 1F may be collectively referred to as the intersection 1, and the signal controllers 2A to 2F may be collectively referred to as the signal controller 2.

The signal controllers at the adjacent intersections are connected to each other by a communication line. That is, the signal controller 2A
Is connected to each of the signal controllers 2B to 2E by a communication line, and the signal controller 2B is connected to the signal controller 2F. In FIG. 1, a communication line connecting the signal controllers to each other in a one-to-one relationship is shown, but the communication mode is not limited to this, and a mode using an integrated device or a mode using wireless may be used.

Each of the intersections 1 is provided with sensors 4 ₁ to 4 ₄ as shown in FIG. The sensors 4 ₁ to _{4 4} are provided on the inflow links 3 _{1 to} 3 ₄ through which the vehicle flows into the intersection 1, respectively. Sensor 4 _1-
4 ₄ each, measuring the traffic flow _q 1 to q ₄ of the vehicle coming to flow into the intersection 1 via the inflow link ₃ 1 to 3 _4. The sensors 4 ₁ to 4 ₄ may be ultrasonic sensors, image sensors, or the like that are widely used at present.

First, the basic principle of the control system of the signal control system according to the present invention will be described.

FIG. 3 shows that the traffic flow of a vehicle flowing from a certain inflow link at a certain intersection A is a time-averaged constant value avg.
When M (units / minute), a vehicle passing through the intersection A according to the red time length redA (seconds), the blue time length greenA (seconds), and the cycle length cycle (seconds) in the inflow path direction. It shows how the cumulative number of changes. A vehicle that had been stopped while the traffic light at the intersection A was red was changed to blue, and then passed through the traffic intersection A at a saturated traffic flow rate M _sat (vehicles / second).
If all the stopped vehicles waiting for the signal disappear, intersection A
The vehicle flowing into the vehicle can pass through the intersection A as it is.

As a result, the delay time in this inflow path at the intersection A is (1/2) * redA * avgM * cycle, which is the area of the hatched portion in FIG. 3 per cycle length. If this is expressed as a delay time per unit time, it becomes (1/2) × redA × avgM. In this control method, the delay time is calculated and evaluated in this way.

In FIG. 3, the inflow traffic flow is constant avg.
Although the delay time for M (units / minute) has been described, it is not a constant flow due to the influence of signal control at an adjacent intersection. However, in order to determine the cycle length and the split that match the traffic flow rate flowing into the intersection A, even if the traffic flow rate is constant at the time average value, it is often sufficient in practical use. Because the traffic flow at time t is M (t), the green time of one cycle is green.
In order to handle all the flow rate in n (seconds), in one cycle,

[Equation 1] The relationship of (1) is established. here,

[Equation 2] Is the time integral of M (t) during a cycle and M _sat is the saturated flow rate. As can be understood from the equation (1), even if the instantaneous value M (t) of the traffic flow rate is not known, if the average flow rate avgM is known, the required cycle length and split can be obtained.

As shown in FIG. 3, the curve of the cumulative number of vehicles passing through the intersection A under the influence of the signal control at the intersection A has a step-like shape with periodicity for each cycle. Figure 4
If the intersection adjacent to the intersection A is B and the distance between the intersection A and the intersection B is L, the intersection A
The curve of the cumulative number of vehicles appearing at the intersection B after traveling the distance L from is generally a curve obtained by shifting the curve of the cumulative number of vehicles passing through the intersection A by L / V on the time axis. here,
V is a set speed of the vehicle traveling from the intersection A to the intersection B, and is set assuming a predetermined value. In reality, since the vehicle group spreads while traveling the distance L, the cumulative number of vehicles passing through the intersection A has the same shape as the intersection B.
Although it does not form a cumulative number of vehicles flowing in, basic values such as its hourly average flow rate are stored.

When the cycle lengths of the intersection A and the intersection B are common, the offset of the intersection B seen from the intersection A and the offset of the intersection A seen from the intersection B can be determined as follows.

The cycle length of the intersection A and the intersection B is c
If the traffic lights at intersection A change from red to blue and the (L / V) mod cycle time elapses after the traffic light at intersection A changes from red to blue, the vehicle group will change from red to blue. You can pass without being obstructed at intersection B. That is, the offset of the intersection B viewed from the intersection A is o
If ffset (A) is set so that offset (A) = (L / V) mod cycle, ... (2), the vehicle group can pass at the intersection B without being blocked. In other words, when δt (A) is defined by δt (A) ≡ (L / V) mod cycle-offset (A), ... (3), if δt (A) = 0, then it is seen from the intersection A. The offset at the intersection B is optimally taken.

Next, consider the case where δt (A) is not zero. The fact that δt (A) is positive means that the intersection A
Δt (A) at the time when a group of vehicles heading for intersection B from
This means that at the time just before, the traffic light display at the intersection B changes from red to blue. On the contrary, when δt (A) is negative, the vehicle group from the intersection A to the intersection B arrives at δ.
This means that the traffic light at the intersection B changes from red to blue at a time t (A) later.

Regarding the direction from the intersection A to the intersection B,
Figure 5 shows the cumulative vehicle number curve when δt (A) is positive.
Further, it is shown in FIG. 6 when it is negative. In each figure, the shaded area represents the delay time that occurs at the intersection B due to the offset being deviated from the optimum value by δt (A).

When the delay time when δt (A) is positive is evaluated using FIG. 5, δt (A) is 0 <δt (A).
When <greenA, the delay time delay (δt (A)) per unit time at the intersection B is delay (δt (A)) = δt (A) · (M _sat −avgM), (4) . Here, greenA is the green time of the intersection A, and avgM is the time average value of the traffic flow of the vehicle traveling from the intersection A to the intersection B. On the other hand, δt (A) is gr
When eaA <δt (A) <cycle, delay (δt (A)) = greenA · (M _sat −avgM) · {1- (δt (A) −greenA) / (cycle−greenA)}, (5) Becomes

Similarly, when the case where δt (A) is minus is evaluated from FIG. 6, the delay time del per unit time of the intersection B when -redA <δt (A) <0 is evaluated.
ay (δt (A)) is: delay (δt (A)) = − δt (A) · (−avgM), (6) −cycle <δt (A) <− redA, delay (δt (A)) ) = RedA · avgM · {1- (δt (A) + redA) / (− cycle + redA)}, ... (7) Here redA is the red time at intersection A.

In FIG. 7, the horizontal axis represents δt (A), and the vertical axis represents the delay time delay (δt per unit time at the intersection B.
(A)) is a graph. δt
When (A) is greenA and −redA, the delay time delay (δt (A)) takes the maximum value delay (δt (A)) _max = cycle · (1-splitB) · av gM, ... (8) I understand. Where splitB is intersection B
And splitB = greenB / cycle,

Although the above description has explained the flow from the intersection A to the intersection B, conversely, from the intersection B to the intersection A.
A similar equation is obtained for the flow to. The time average flow rate from the intersection B to the intersection A is avgm, the offset of the intersection A seen from the intersection B is offset (B), and δt (B) is δt (B) ≡ (L / V) mod cycle-offset ( B), ... (3) ′, if δt (B) is positive, 0 <δt
The delay time per unit time delay (δt (B)) at intersection A when (B) <greenB is: delay (δt (B)) = δt (B) · (M _sat −avgm), (9) And when greenB <δt (B) <cycle, delay (δt (B)) = greenB · (M _sat −avgm) · {1- (δt (B) −greenB) / (cycle−greenB)}, ... (10) However, greenB is the green time of the intersection B. On the other hand, when δt (B) is negative, -redB <
The delay time per unit time at the intersection A when δt (B) <0 is delay (δt (B)) = − δt (B) · avgm, (11), and −cycle <δt (B) < With −redB, delay (δt (B)) = redB · avgm · {1- (δt (B) + redB) / (− cycle + redB)}, ... (12) Here redB is the red time at intersection A.

FIG. 8 shows the relationship between the offset offset (A) when the intersection A is viewed from the intersection A and the offset offset (B) when the intersection A is viewed from the intersection B. As can be seen from FIG. 8, since there is a relationship of offset (A) + offset (B) = cycle, ... (13), the relationship between δt (A) and δt (B) is also δt (A) ≡ (L / V ) Mod cycle-offs
et (A), δt (B) ≡ (L / V) mod cycle-offs
From et (B), δt (A) + δt (B) = 2 · {(L / V) mod cycle} -cycle e, ... (14) From this equation, it can be seen that δt (A) and δt (B) are not independent but have constraints.

FIG. 9 shows the delay time delay at the intersection B.
(Δt (A)) and the delay time delay at the intersection A
It is a graph which shows ((delta) t (B)). At this time, if the total delay time delay _{A + B} is defined as delay _{A + B} = delay (δt (A)) + delay (δt (B)), (15), the total delay time delay _{A + B} is δt.
It is a two-variable function of (A) and δt (B). Figure 10
Total delay time delay _{A + B} (δt (A), δt
(B)) is illustrated. A coordinate point (δt (A), δ
The total delay time delay _{A + B at} t (B) takes a larger value as the rhombic line surrounding the coordinate point becomes thicker. Dotted line 11 indicates δt (A) and δ under the constraint condition of equation (14).
t (B) represents a possible value. Of the coordinate points on the dotted line 11, delay _{A + B} (δt (A), δ
The coordinate point that minimizes t (B) is the combination of δt (A) and δt (B) that minimizes the sum of the delay times that occur at intersection A and intersection B. Intersection A and intersection B
Δt (A) and δ that minimize the sum of delay times
From the set of t (B), the optimum values of the offset offset (A) when the intersection B is seen from the intersection A and the offset offset (B) when the intersection A is seen from the intersection B can be obtained.

As can be seen from FIG. 10, as δt (A) and δt (B) move on the dotted line 11, there are cases in which some coordinates at which the function value takes a minimum value may appear, which is very small. In the method of searching with the step size, it is practically impossible to obtain the minimum value of delay _{A + B.} Therefore, instead of applying the conventional simple mathematical programming method, first, the approximate solution of the minimum value is roughly calculated on the delay _{A + B} based on FIG. 10, and then the minute step is searched around the approximate solution. Two
Preferably, a step search is performed.

In the control method of the signal control system according to the present invention, the above-mentioned basic principle is used. More specifically, the control method of the signal control system according to the present invention responds to the first step of determining the target value of the control parameter by using the above-mentioned basic principle and the target value of the control parameter determined in the first step. And a second step of defining a control parameter for controlling the signal lamp is executed.

First stage: In the first stage, intersections 1A-1
The target value of the control parameter of F is the signal controller 2
A to 2F. That is, the signal controller 2A-
2F, for each of the intersections 1A to 1F, a cycle length target value that is a target value of cycle length, a split target value that is a target value of split, and an offset target value when the own intersection is viewed from an adjacent adjacent intersection. The offset target value that is As will be described later, since the cycle length, split, and offset of each intersection 1A to 1F are controlled so as to approach the cycle length target value, the split target value, and the offset target value, respectively, the cycle length target Value, split target value, and offset target value by optimizing each intersection 1A-1
The delay time that occurs at F is minimized.

In the following, the process of determining the cycle length target value, split target value and offset target value will be described taking the intersection 1A as an example. As for the other intersections 1B to 1F, the cycle length target value,
A split target value and an offset target value are set.

Referring to FIG. 11, the average traffic flow rate of vehicles flowing into intersection 1A from intersection 1B adjacent to intersection 1A is avgMba, and the average traffic flow rate of vehicles flowing from intersection 1E to intersection 1A is avgMea. Then, the number of vehicles flowing into the intersection 1A from the intersection 1B during one cycle is avgMba × cycle.
The number of vehicles flowing from the intersection 1E to the intersection 1A is avgMea × cycle (vehicle).
At intersection 1A, green time cycle × split (B
During E) av flowing from intersection 1B to intersection 1A
Vehicle of gMba × cycle (vehicle) and avgMea × cycle (vehicle) flowing from intersection 1E to intersection 1A
Need to be dealt with the vehicle. Where sprit
(BE) represents splits assigned to the intersections 1B, 1A and 1E. When this necessary condition is expressed by an equation, Max (avgMea, avgMea) <split (BE) · M _sat BE (16). Here, M _sat BE is the intersection 1B, 1A, 1
It is the saturated traffic flow rate in the E direction.

Similarly, the necessary condition in the directions of the intersections 1C, 1A and 1D is Max (avgMca, avgMda) <split (CD) · M _sat CD (17). Here, avgMca is the average traffic flow rate of vehicles flowing from the intersection 1C to the intersection 1A, and avMca
gMda is the average traffic flow of vehicles flowing into the intersection 1A from the intersection 1D, split (CD) is a split assigned in the directions of the intersections 1C, 1A, 1D, and M _sat CD is the intersection 1C, 1A, It is the saturated traffic flow rate in the 1D direction.

The green time in the directions of intersections 1B, 1A and 1E is
At that time, it is necessary to guarantee the pedestrian green time length ped_timeBE at which the pedestrian can cross the road, and similarly, the pedestrian green time length at which the pedestrian can cross the road for the green time in the directions of intersections 1C, 1A and 1D. Sa ped_timeC
We need to guarantee D. Therefore, the following relational expression is also a necessary condition. cycle × sprit (BE)> ped_timeBE, ... (18) cycle × sprit (CD)> ped_timeCD. … (19)

Further, the cycle length cycle is set to the directions of the intersections 1B, 1A, 1E or the intersections 1C, 1A, 1
It must be determined in consideration of the loss time λ that is not assigned to any of the D directions, that is, the time for displaying red in all directions is required.

In summary, the split split (BE) and split (CD) at the intersection 1A must satisfy the condition represented by the following equation. _{split (BE)> Max {Max} (avgMba, avgMea) / M s at BE, ped_timeBE / cycle}, ... (20) split (CD)> Max {Max (avgMca, avgMda) / M s at CD, ped_timeCD / cycle }, ... (21) cycle = λ / (1-split (BE) -split (CD)). (22) The signal controller 2A provided at the intersection 1A is expressed by the equation (20).
~ Intersection 1B, 1A, 1E to satisfy (22)
Direction split target value split _BEA (BE), intersection target values split 1C, 1A, 1D direction split target value spli
t _CAD (CD) and cycle length target value cycle
_Ask for _A.

Practically, the cycle length target value cycle _A calculated by the equation (22) is used by raising it to a value that is an integral multiple of 2 seconds, for example. Therefore, the cycle length target value cycle _A is discretized at predetermined intervals. When discretizing the cycle length target value cycle _A , the split target values split _BEA (BE) and split _{CA D}
(CD) is such that equation (22) still holds,
It is increased in proportion to the original value. The procedure up to this point is the starting point for calculating the cycle target value and the split target value in the first stage.

The cycle target value and the split target value are similarly calculated in the signal controllers 2B to 2F provided at the intersections 1B to 1F other than the intersection 1A.

Further, each of the signal controllers 2A to 2F transmits the cycle target value and the split target value defined by itself to the signal controller provided at the adjacent intersection adjacent to the own intersection where the signal controllers 2A to 2F are provided. In addition, the cycle target value and the split target value are received from each of the signal controllers provided at the adjacent intersections. That is, intersection 1
The signal controller 2A provided in A has the cycle length target value and the split target value calculated by the signal controllers 2B-2E provided in the intersections 1B-1E adjacent to the intersection 1A,
Receive via communication line.

The signal controller 2A determines whether or not there is an intersection having the same cycle length target value among the intersections (that is, the intersections 1B to 1E) adjacent to the intersection 1A which is its own intersection. When there are intersections with the same cycle length target value, the signal controller 2A performs offset coordination of the intersections with the same cycle length target value with the largest average traffic flow to the intersection 1A. Determined as an intersection. The signal controller 2A determines the offset target value of the own intersection (intersection 1A) viewed from the offset cooperative intersection,
It is determined in the same manner as the above-mentioned basic principle.

That is, first, δt (A) and δt (B) are δt (A) ≡ (L / V) mod cycle _A- offset (A), ... (23) δt (B) ≡ (L / V) mod cycle _A- offset (B), ... (24) L: Distance between offset coordinated intersection and intersection 1A, V: Set speed of link between offset coordinated intersection and intersection 1A, cycle _A : Intersection 1A Cycle length target value (= cycle length target value of offset cooperative intersection) offset (A): offset target value of offset cooperative intersection seen from intersection 1A offset (B): offset target value of intersection 1A viewed from offset cooperative intersection Is defined as Here, offset (A) + offset (B) = cycle _A , ... (25) is established.

Furthermore, the formula for calculating the delay time delay (δt (A)) that the vehicle heading from the intersection 1A to the offset cooperative intersection is kept waiting at the offset cooperative intersection is
It is determined according to equations (4) to (7). At this time, the green time greenA and the red time RedA included in the formulas (4) to (7) are calculated from the cycle length target value and the split target value of the intersection 1A, and are expressed in the formulas (4) to (7). As avgM included, the average traffic flow rate of the vehicle from the intersection 1A toward the offset cooperative intersection is used.

Similarly, the formula for calculating the delay time delay (δt (B)) that the vehicle heading from the offset cooperative intersection to the intersection 1A is kept waiting at the intersection 1A is the equation (9).
~ (12). At this time, equation (9)-
The green time greenB and the red time RedB of (12) are calculated from the cycle length target value and the split target value of the offset cooperative intersection, and the avgm included in the equations (9) to (12) is the offset cooperative intersection. The average traffic flow from the vehicle to the intersection 1A is used. To calculate the blue time greenB and the red time RedB,
The signal controller 2A receives the cycle length target value and the split target value of the offset cooperative intersection from the signal controller that controls the offset cooperative intersection.

As a result, the total delay time delay _{A + B}
{≡delay (δt (A)) + delay (δt
(B))} is determined.

Then, the total delay time delay _{A + B} is minimized under the constraint condition: δt (A) + δt (B) = 2 · {(L / V) mod cycle _A } -cycle _A , ... (26). Do δt
(A) and δt (B) are determined. Signal controller 2A
From the determined δt (A) and δt (B), the equation (2
Intersection 1A as seen from the offset cooperative intersection using 4)
The offset target value offset (B) of is determined.

For example, it is assumed that the cycle length target values determined for the intersections 1B, 1C, and 1D are the same as those of the intersection A, and the average traffic flow rate of vehicles traveling from the intersection 1B to the intersection 1A is the maximum. In this case, the signal controller 2
A determines that the intersection 1B is an offset cooperative intersection. The signal controller 2A uses the offset target value of of the intersection 1A viewed from the offset cooperative intersection as described above.
Determine fset (B).

Even if the intersections adjacent to the intersection 1A have the same cycle length target value, the intersection 1A
If the average traffic flow to is not maximum, the offset target value cannot be determined in a coordinated manner. The signal controller 2A determines the offset target value independently of the other signal controllers. At this time, for example, when the offset target values are not determined in a coordinated manner between the intersections 1A and 1B, the total delay time at the intersections 1A and 1B is at worst red * (avgMab + avgMba). However, avgMab is the average traffic flow of the vehicle from the intersection 1A to the intersection 1B, and is avgMba.
Is an average traffic flow rate of vehicles traveling from the intersection 1B to the intersection 1A.

The fact that the cycle length target value is discretized at a predetermined interval as described above is important in determining the offset coordinated intersection. When the cycle length target values are not discretized, the cycle length target values that are very close to each other may be determined at adjacent intersections, but the matching cycle length target values are determined. Is almost impossible. Therefore, the cycle length target values are discretized at predetermined intervals so that the cycle length target values are easily matched.

Next, a cycle length target value that is longer than the cycle length target value calculated at the intersection 1A is adjacent to the intersection 1
If specified for B to 1E, signal controller 2A
Select the closest cycle length target value that is close to the self-determined cycle length target value, and change the self-determined cycle length target value or the nearest cycle target value. , Judge to keep it as it is.

When the cycle length target value of itself is lengthened in accordance with the nearest cycle length target value, an offset can be selected, so that a desirable portion where the delay time can be reduced and the cycle length target value can be lengthened. The advantages and disadvantages will be compared with a portion where the dead time is generated at the intersection of its own and the delay time becomes large, and the offset effect until then is lost due to the change of the cycle target value, resulting in a large delay time. As a result of the comparison, it is determined whether or not the cycle length target value can be changed.

A specific example of determining whether or not the cycle length target value can be changed will be described. Referring to FIG. 11, regarding intersections 1A and 1B adjacent to each other, intersections 1A to 1B
AvgMab is the average traffic flow of the vehicles heading toward the intersection, and a is the average traffic flow of the vehicles traveling from the intersection 1B toward the intersection 1A.
vgMba. When the cycle length target values are different between the intersections 1A and 1B, the total delay time delay at the intersections 1A and 1B is, as shown in FIG. 12, delay = (1/2) × (redA + redB) × (AvgMab + avgMba), ... (27)

On the other hand, the intersections 1B to 1E adjacent to the intersection 1A
If different cycle length target values are calculated for the intersection 1A, the signal controller 2A controlling the intersection 1A
Whether the cycle length target value of A is adjusted to a cycle length target value that is the closest value and is longer than the cycle length target value of the intersection 1A among the cycle length target values determined for the adjacent intersections 1B to 1E. Determine whether It is assumed that the adjacent intersection at which the cycle length target value that is longer than the cycle length target value of the intersection 1A and is the closest value is calculated is the intersection 1B. FIG. 13 shows an example of a comparison table for determining whether to match the cycle length target value Ca of the intersection 1A with the cycle Cb of the intersection 1B.
In FIG. 13, the advantages and disadvantages of the delay time due to the change of the cycle length target value are compared with all the intersections adjacent to the intersection 1A.

As a result of the above, the cycle target value, split target value, and offset target value are determined. The above-mentioned first step is performed periodically. The signal controller 2A that controls the intersection 1A exchanges information about the signal that controls the adjacent intersections 1B to 1E with the cycle length target value and the split target value, and repeats the above calculation. After the cycle target value, the split target value, and the offset target value are calculated once, until the cycle target value, the split target value, and the offset target value are calculated again, the second stage described below is performed. Be seen.

Second stage: In the second stage, the control parameter being executed is gradually changed toward the target value. That is,
Each signal controller 2 determines the cycle length of its own intersection, the split, and the offset between the own intersection and the adjacent intersection, the cycle length target value and the split target value calculated in the first stage. , And the offset target value are gradually approached.

After the cycle length of the self-intersection, the split, and the offset between the self-intersection and the adjacent intersection reach the cycle-length target value, the split target value, and the offset target value, respectively, signal control is performed. Aircraft 2 adjusts the split and offset of its own intersection within a predetermined range according to the actual traffic conditions. The adjustment of the split and the offset is performed on the basis of whether or not the actual measurement value of the delay time obtained by changing the split and the offset in increments of plus and minus can be reduced.

However, if the cycle length, the split, and the offset do not reach the cycle length target value, the split target value, and the offset target value, if the split and the offset are adjusted, the adverse effect is obtained. It is possible that the delay time increases. Therefore, splitting and offset adjustment are not performed during the transition to each target value.

In the above-mentioned first step, in the method of determining the cycle length target value and the split target value by the measured value of the average traffic flow rate of the vehicles flowing into each intersection, the control delay is remarkable. Could be. As a result, the responsiveness to traffic changes may deteriorate. In order to deal with this, as shown in FIG. 14, the average traffic flow rate avgM of the inflow link at a certain intersection A is calculated by measuring the average traffic flow rate avgM at each of the links flowing into the adjacent intersection B connected to the inflow link. It is preferable to calculate by a linear function. For example, the following forms are possible. avgM = a1 (t, week) × M1 (t) + a2
(T, week) × M2 (t) + a3 (t, week)
× M3 (t). M1 (t), M2 (t), and M3 (t) are measured values of the traffic flow volume of the vehicle flowing in from each inflow link of the adjacent intersection B upstream of the certain intersection A. Some of the vehicles that flow into the adjacent intersection B will flow into the intersection A. a1 (t, week), a2 (t, week), a
3 (t, week) is a coefficient of the linear function. a1
(T, week), a2 (t, week), a3 (t,
Since "week) varies depending on the time t, the day of the week week, and the intersection, the average traffic flow rate at each intersection is actually measured, and the coefficient of the linear function is learned so as to reduce the error with that. As a learning method, for example, ARMA (autoregressive model), neuro, reinforcement learning, or the like may be used.

FIG. 15 shows an example of the software module configuration of the signal controller 2 for implementing the above control method.

[0072] Traffic flow measurement module ₆₁ is detector 4
To measure the traffic flow from _one to four _4.

[0073] Communication module 6 ₂ is connected via a communication line with an adjacent intersection exchange information.

Cycle / Split Planning Module 6 ₃
Realizes the function of calculating the cycle length target value and the split target value according to the above-mentioned control method based on the measured traffic flow rate.

[0075] Offset planning module 6 ₄ calculates the optimum offset target value of between the adjacent intersection in accordance with the control method described above. This offset planning module 6 _4, above cycles / split planning module 6
By means of ₃ , the above-mentioned first step is executed.

[0076] Control executed module 6 ₅ is provided to perform the second stage of the above. Control execution module 6 _5, move to the target value of the control parameter calculated in the first step, to actually control the signal lamp device. After control execution module 6 ₅ which has once reached the target value, in accordance with the traffic conditions at that time, the split is adjusted modify the offset.

[0077]

According to the present invention, it is possible to communicate with each signal controller at an adjacent intersection without having a large-scale central unit, and the signal controllers at each intersection can be automatically connected to each other according to changes in traffic conditions. A distributed signal control system is provided that calculates and controls cycles, splits, and offsets. In other words, instead of predetermining the control range such as the sub area and applying a common cycle in it, a signal control system that automatically forms the control range according to the traffic situation while evaluating the delay time is provided. Provided. Further, there is provided a signal control system in which each signal controller automatically generates an offset in the direction of high traffic, rather than applying a patterned offset within the sub-area.

Further, according to the present invention, by automatically calculating the control parameter according to the change of the traffic condition,
Provided is a distributed signal control system capable of significantly reducing the operating cost and maintenance cost for calculating and reviewing control parameters.

Further, according to the present invention, the enormous and complicated system problem of the centralized signal control system by the central unit and the global optimization by fitting to the extreme value of the distributed signal control system will be carried out. Provided is a distributed signal control system that solves both of the problems that are difficult to approach.

[Brief description of drawings]

FIG. 1 shows an embodiment of a signal control system according to the present invention.

FIG. 2 is a detailed view of the vicinity of an intersection 1.

FIG. 3 is a diagram showing a cumulative number of vehicles curve at one intersection, and is a diagram for explaining a delay time caused by signal control.

FIG. 4 is a diagram showing a relationship between two intersections.

FIG. 5 is a diagram showing a cumulative vehicle number curve and a delay time between two intersections when δt (A) is positive.

FIG. 6 is a diagram showing a cumulative vehicle number curve and a delay time between two intersections when δt (A) is negative.

FIG. 7 is a delay time delay at the intersection 1B.
(Δt (A)) is shown.

FIG. 8 shows the offset between two intersections.

9 shows the delay time shown in FIG. 7 for each of two intersections.

FIG. 10 is a diagram showing the delay time of FIG. 9 in one graph.

FIG. 11 is a diagram for explaining a traffic flow rate at an intersection.

FIG. 12 shows a cumulative vehicle number curve and a delay time at two intersections having different offsets.

FIG. 13 is a diagram comparing increase / decrease in delay time when an intersection cycle is independently used and when it is adjusted to an adjacent intersection.

FIG. 14 is a diagram for explaining a traffic flow rate at an upstream intersection.

FIG. 15 shows software modules constituting a signal controller according to the present invention.

[Explanation of symbols]

1 ₁ to ₁₆ : Intersection 2 ₁ to 2 ₆ : Signal controller 3 _{1 to} 3 ₄ : Inflow path to intersection 4 ₁ to 4 ₄ : Sensor 6 _{1 to} 6 ₅ : Software module constituting signal controller

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mikio Ide             2-1-1 Niihama, Arai-cho, Takasago, Hyogo Prefecture             Takasago Laboratory, Mitsubishi Heavy Industries, Ltd. F-term (reference) 5H180 AA01 CC04 CC11 DD02 JJ02                       JJ06 JJ12

Claims (9)

[Claims] 1. A plurality of signal controllers provided at each of a plurality of intersections, and a measuring means for measuring a traffic flow rate at each of the intersections, each of the signal controllers being provided respectively. Based on the traffic flow of the own intersection and the information sent from the adjacent intersection signal control device provided at the adjacent intersection adjacent to the own intersection, the cycle length of the own intersection, the split, and the own intersection and the adjacency A distributed signal control system that determines the offset to and from an intersection. 2. The distributed signal control system according to claim 1, wherein each of the signal controllers is (a) an average value of a traffic flow rate of a link from the adjacent intersection to the own intersection in a predetermined period. Calculate the time average value, using the distance from the adjacent intersection to the own intersection and the time average value, the cycle length target value of the own intersection, the split target value, and the own intersection and the adjacent intersection (B) the cycle length target value, the split target value, and the offset target value are each stepwise determined by the cycle length target value, the split target value, and the offset target value. A distributed signal control system that adjusts the cycle length, the split, and the offset to approach. 3. The distributed signal control system according to claim 2, wherein each of the signal controllers has the cycle length target value of the own intersection and the adjacent intersection determined by the adjacent intersection signal controller. When the cycle length target value matches, the one having the largest traffic flow to the own intersection among the adjacent intersections matching the cycle length target value is determined as an offset cooperative intersection, and the offset cooperative intersection A distributed signal control system for determining the offset target value of a self-intersection based on the cycle length target value and the split target value. 4. The distributed signal control system according to claim 3, wherein the cycle length target value determined by each of the signal controllers is discretized at predetermined intervals. 5. The distributed signal control system according to claim 3, wherein each of the signal controllers includes: (c) a vehicle traveling from the adjacent intersection where the cycle length target values match to the own intersection. A total delay time that is a sum of a first delay time waited at the own intersection and a second delay time waited at the adjacent intersection where the target cycle length of a vehicle traveling from the own intersection to the adjacent intersection matches , A step represented by a function of δ ₁ and δ ₂ defined below, and δ ₁ = {(L / V) mod C} -O ₁ , δ ₂ = {(L / V) mod C} -O ₂ , L: Distance between the adjacent intersection and the own intersection V: Predetermined speed C: The cycle length target value O ₁ that coincides between the own intersection and the adjacent intersection: The off of the own intersection viewed from the adjacent intersection Set the target value O _2: wherein determining a constraint between the said offset target value of adjacent intersections; (d) [delta] ₁ and [delta] ₂ viewed from the self intersection satisfied (e) the constraint condition, and, the Calculating δ ₁ and δ ₂ that minimize the total delay time, and (f) calculating the offset target value based on δ ₁ and δ ₂ that minimize the total delay time. A distributed signal control system to implement. 6. The distributed signal control system according to claim 2, wherein each of the signal controllers uses the distance from the adjacent intersection to the own intersection and the time average value,
Determining the provisional cycle length target value of the self-intersection, and, each of the signal controller, the provisional cycle length target value of the self-intersection, and the provisional cycle length target value of the adjacent intersection When they do not match, the cycle length target value of the self-intersection is set to the self-intersection and / or the provisional cycle length target value of the self-intersection and the provisional cycle length target value of the adjacent intersection. A distributed signal control system which is set so that the delay time generated at the adjacent intersection coincides with the smaller delay time. 7. The distributed signal control system according to claim 2, wherein each of the signal controllers receives the time average value from a link other than a link connecting to the own intersection to the adjacent intersection. A distributed signal control system that calculates as a function value of a time average value calculation function that is a function of an actual measurement value of traffic flow. 8. The distributed signal control system according to claim 7, wherein each of the signal controllers uses a function parameter of the time average value calculation function as a time average value of an actually measured traffic flow rate of the inflow link. A distributed signal control system that modifies the function parameter so that an error from the function value becomes small. 9. The distributed signal control system according to claim 2, wherein each of the signal controllers further comprises: (g) the cycle length, the split, and the offset being substantially the cycle length. Distributed signal control for executing a step of adjusting and changing the split and the offset within a predetermined range by using the time average value after matching the target value, the split target value, and the offset target value, respectively. system.