Intersection signal control method and system

Abstract

The invention discloses an intersection signal control method and system, and the method comprises a method for generating a corresponding basic control scheme for constructing an intersection, and comprises the following steps: merging the driving paths of the constructed intersection, and obtaining a plurality of driving path groups; determining a conflict relationship between the driving path groups, and constructing an undirected graph based on the conflict relationship to obtain the intersection model; extracting a local maximum complete sub-graph of the intersection model, and determining a path group set corresponding to the local maximum complete sub-graph based on the driving path group corresponding to each local maximum complete sub-graph; and generating a corresponding basic control scheme based on the path group set. According to the method, the intersection model is constructed based on the undirected graph, and the conflict relationship between the driving paths is clarified based on the intersection model, so that the construction of the intersection model is not limited by the road layout, and the method has universality.

Description

Technical Field

[0001] The invention relates to the field of traffic signal control, and in particular to an intersection signal control solution. Background Art

[0002] Signal control needs to separate or combine the turning traffic based on the intersection geometry, traffic demand and control objectives, and allocate road rights to each group of traffic in an orderly manner to avoid or reduce traffic conflicts and ensure smooth road conditions.

[0003] At present, the models used for signal design, especially those involving phase design, do not adequately reflect the flexibility of signal control, have certain limitations in their scope of application, and the model construction process is relatively complex.

[0004] Some studies have considered the traffic flow conflicts and time-space utilization at intersections and used graph models to optimize phase combinations. However, the generality of the model is limited, making it difficult to model intersections with complex layouts, and the reflection of the phase combination division relationship is ignored. Summary of the invention

[0005] In view of the shortcomings that the intersection model constructed in the prior art ignores the reflection of the phase combination division relationship and is difficult to model intersections with complex layouts, the present invention provides an intersection model constructed based on an undirected graph and an intersection signal control technology based on the intersection model.

[0006] In order to solve the above technical problems, the present invention is solved by the following technical solutions:

[0007] A method for controlling intersection signals, for generating a corresponding basic control scheme for a constructed intersection, wherein the constructed intersection includes a main intersection, comprises the following steps:

[0008] The driving paths of the constructed intersection are merged to obtain a plurality of driving path groups; the road sections corresponding to the driving paths in the same driving path group entering the main intersection are the same, and the driving paths in the same driving path group do not conflict with each other;

[0009] Determine the conflict relationship between each driving path group, and construct an undirected graph based on the conflict relationship to obtain the intersection model; in the intersection model, the node represents the driving path group, and the edge represents that the driving path groups corresponding to the two connected nodes do not conflict with each other;

[0010] Extracting the local maximum complete subgraph of the intersection model, and determining a path group set corresponding to the local maximum complete subgraph based on the driving path groups corresponding to each local maximum complete subgraph;

[0011] A corresponding basic control scheme is generated based on the path group set, wherein the basic control scheme includes a plurality of phases, the phases correspond to the path group set one by one, and the path group set is used to indicate the traffic flow of the traffic state in the corresponding phase.

[0012] The present invention constructs an intersection model for an intersection based on the construction of an undirected graph. The constructed intersection model can clarify the conflict relationship between driving paths, so that the construction of the intersection model is not restricted by the road layout and has universality; and it maximizes the flexibility of signal scheduling and is convenient for the design and optimization of traffic signals.

[0013] As an implementable method, the specific steps of constructing the intersection model are:

[0014] Combine the driving path groups in pairs to generate a number of undirected pairs, and obtain a first undirected pair set;

[0015] Based on the conflict relationship, the two conflicting driving path groups are made to form an undirected pair to obtain a conflicting path group pair, and a second undirected pair set is constructed based on the obtained conflicting path group pair;

[0016] Obtaining the complement of the second undirected pair set in the first undirected pair set to obtain a third undirected pair set, wherein the undirected pairs in the third undirected pair set are non-conflicting path pairs;

[0017] The intersection model is constructed based on the third undirected pair set.

[0018] As an implementable method:

[0019] The driving path includes a first path, wherein the first path is a path in which both the entry section and the exit section are located at the main intersection;

[0020] A driving path group is determined based on the first path group, where the first path group is a path group obtained by merging the first paths.

[0021] As an implementable embodiment, the construction intersection further has at least one slave intersection;

[0022] Each secondary intersection is treated as a single intersection for path segmentation, and a local path corresponding to each secondary intersection heading to the main intersection is obtained;

[0023] Merge each pair of local paths corresponding to the intersections to obtain a corresponding local path group, where the local paths in the same local path group do not conflict with each other;

[0024] Based on the first path group, connecting and merging the first path group and each local path group to obtain a corresponding second path group;

[0025] The second path group and the first path group not connected to the local path group are used as a driving path group.

[0026] In the present invention, the intersection with a very short spacing adjacent to the main intersection is taken as its subordinate intersection, and the path entering from the subordinate intersection and exiting from the main intersection is taken as the driving path, so that the obtained intersection model can reflect the path conflict caused by diversion in the intersection, which is convenient for coordinating the corresponding traffic signals of the subordinate intersection.

[0027] As an implementable method:

[0028] When there is a conflict between first path groups located at the same main intersection and / or between local path groups located at the same secondary intersection in two driving path groups, it is determined that the two driving path groups conflict.

[0029] As an implementable method:

[0030] When there are conflicting first paths in the two first path groups, it is determined that the two first path groups conflict;

[0031] When there are conflicting local paths in two local path groups from the same intersection, it is determined that the two local path groups conflict.

[0032] The present invention also proposes an intersection signal control method for dynamically adjusting a traffic signal of a constructed intersection, wherein the constructed intersection includes a main intersection, and dynamically adjusting a traffic signal corresponding to the main intersection at a current phase based on a basic control scheme, wherein the basic control scheme is a basic control scheme generated according to any one of the above methods;

[0033] The following steps are involved:

[0034] Based on the path group set corresponding to the corresponding phase in the basic control scheme, determine the first candidate path group of the signal to be switched, the first candidate path group is the first path group corresponding to the state at the main intersection switching from pass to prohibition when switching from the current phase to the next phase, and the first path group is the path group corresponding to the path whose entry section and exit section are both located at the main intersection;

[0035] Determine the green light reference duration of the current phase based on the preset time configuration data, and perform one or more early end judgments before the end of the green light period corresponding to each first candidate path group based on the green light reference duration;

[0036] When the first candidate path group has a traffic demand, it is determined that no adjustment is made, and the right-of-way end time is determined based on the green light reference duration;

[0037] When there is no traffic demand for the first candidate path group, it is determined to end early, and the first candidate path group is advanced to the corresponding right-of-way end time.

[0038] The present invention judges the early termination of the first candidate path group based on the basic control scheme and the current traffic demand status, and terminates the green light period of the first candidate path group without traffic demand in advance, thereby avoiding the waste of the green light period and effectively alleviating the traffic pressure.

[0039] As an implementable method:

[0040] Based on the path group set corresponding to the corresponding phase in the basic control scheme, determine the second candidate path group to be switched by the current signal, the second candidate path group being the first path group in which the state at the main intersection is switched from prohibited to pass when switching from the current phase to the next phase;

[0041] Perform early switching judgment on each second candidate path group respectively, specifically:

[0042] Acquire a first candidate path group that conflicts with the second candidate path group at the main intersection, and obtain a third candidate path group;

[0043] Acquire a green light interval time between the second candidate path group and each third candidate path group, where the green light interval time is used to indicate an interval time required to switch from the corresponding third candidate path group to the second candidate path group;

[0044] When the interval time periods corresponding to the third candidate path groups all reach the corresponding green light interval time, the state of the second candidate path group is switched to pass.

[0045] The present invention ends the green light period of the first candidate path group without traffic demand in advance, and sets the green light of the second candidate path group in advance when all the conflicting first path groups of the second candidate path group reach the corresponding green light interval time, thereby realizing dynamic optimization of traffic flow.

[0046] As an implementable method, a method for calculating the green light interval time corresponding to switching from the first switching path group to the second switching path group is:

[0047] Acquire all conflicting path pairs in the first switching path group and the second switching path group, and obtain corresponding candidate path pairs, wherein the candidate path pairs include the conflicting first switching path and the second switching path, the first switching path belongs to the first switching path group, and the second switching path belongs to the second switching path group;

[0048] Calculate the path interval time corresponding to each candidate path pair, and take the maximum value of the path interval time as the corresponding green light interval time;

[0049] The method for calculating the path interval time corresponding to each candidate path pair is:

[0050] Obtaining a vehicle start time and a clearing time for clearing the traffic flow corresponding to the first switching path, wherein the vehicle start time is a reference value set based on the traffic flow type and the turning type for clearing the traffic flow, and the clearing time is used to indicate the time required for the clearing traffic flow to leave the corresponding conflict point;

[0051] Acquire an entry time of an incoming vehicle flow corresponding to the second switching path, where the entry time is used to indicate a time required for the incoming vehicle flow to reach the conflict point;

[0052] The corresponding path interval time is calculated based on the vehicle start time, the clearing time and the driving-in time.

[0053] In the present invention, each conflict point corresponds to a green light interval, and the green light interval is calculated based on the traffic status of the corresponding first path group pair, so as to perform flexible scheduling with the first path group as the granularity during phase switching.

[0054] As an implementable method:

[0055] The constructed intersection further comprises at least one slave intersection;

[0056] The first candidate path group for the green light period to be ended early is used as the target path group;

[0057] The green light end time of the upstream path group corresponding to the target path group is advanced, and the upstream path group is used as the new target path group to continue coordinated control.

[0058] As an implementable method:

[0059] The constructed intersection further comprises at least one slave intersection;

[0060] The second candidate path group to be entered into the green light period in advance is taken as the target path group;

[0061] The green light start time of the upstream path group corresponding to the target path group is advanced, and the upstream path group is used as the new target path group to continue coordinated control.

[0062] The present invention coordinates the signal switching of the path groups corresponding to the dominant traffic flows between adjacent secondary intersections based on the dynamic adjustment of the traffic signals of the first candidate path group and / or the second candidate path group in the main intersection.

[0063] The present invention also provides an intersection signal control system, which is used to execute any one of the above-mentioned intersection signal control methods.

[0064] The present invention has significant technical effects due to the adoption of the above technical solution:

[0065] The present invention constructs an intersection model for an intersection based on the construction of an undirected graph. The constructed intersection model can clarify the conflict relationship between driving paths, so that the construction of the intersection model is not restricted by the road layout and has universality; and it maximizes the flexibility of signal scheduling and is convenient for the design and optimization of traffic signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0067] Figure 1 It is a schematic diagram of a flow chart of generating a basic control scheme in a method for controlling intersection signals of the present invention;

[0068] Figure 2 It is a structural schematic diagram of a constructed intersection including a main intersection and a secondary intersection;

[0069] Figure 3 yes Figure 2 The undirected graph model of conflicting path pairs corresponding to the constructed intersection is shown;

[0070] Figure 4 yes Figure 2 The intersection model corresponding to the constructed intersection shown;

[0071] Figure 5 yes Figure 4 The corresponding local maximum complete subgraph;

[0072] Figure 6 It is a schematic diagram of a flow chart of a method for controlling intersection signals of the present invention for dynamically adjusting the corresponding traffic signals of the main intersection;

[0073] Figure 7 When from Figure 5 Schematic diagram of adjusting the start and stop time of the corresponding right of way when sub-graph (2) switches to sub-graph (5). DETAILED DESCRIPTION

[0074] The present invention is further described in detail below in conjunction with embodiments. The following embodiments are for explanation of the present invention but the present invention is not limited to the following embodiments.

[0075] The invention discloses an intersection signal control method, which is used to construct a corresponding intersection model for constructing an intersection, and to generate a corresponding basic control scheme based on the intersection model.

[0076] construct intersections;

[0077] It consists of a main intersection, that is, V = {I 0}, V represents the intersection set corresponding to the constructed intersection, I 0 Indicates a major intersection;

[0078] Or, it is composed of a main intersection and at least one secondary intersection corresponding to the main intersection, that is, V = {I 0 ,I 1 ,…,I k ,},I 0 Indicates the main intersection, I K (K=1,…,k) represents from the intersection.

[0079] In this embodiment, the target intersection is taken as the main intersection, and when there are one or more intersections that are too close to the target intersection, such intersections with ultra-short spacing are combined for consideration, that is, such intersections with ultra-short spacing are taken as slave intersections, and the main intersection and its slave intersections are considered as a whole. Therefore, in actual applications, based on the signal control situation of the main intersection, the slave intersections can be coordinated and controlled accordingly.

[0080] by Figure 2 As an example, the intersection shown in FIG. 1 includes a main intersection and a secondary intersection, wherein the secondary intersection is a T-shaped intersection. The intersection set V is represented as {I 0 , I 1};

[0081] Those skilled in the art may determine the secondary intersection according to actual needs, for example, an intersection within ten meters or twenty meters from the main intersection may be regarded as a secondary intersection, and this specification does not impose any detailed restrictions thereon.

[0082] This embodiment does not limit the type and layout of intersections, is applicable to conventional intersections and unconventional intersections, and is compatible with the setting of waiting areas.

[0083] Reference Figure 1 , the method for generating the basic control scheme specifically includes the following steps:

[0084] A100, divide the driving path group of the constructed intersection;

[0085] Merging the driving paths of the constructed intersection to obtain a number of driving path groups;

[0086] Those skilled in the art may merge the driving paths according to actual needs, so as to ensure that the road sections corresponding to the driving paths in the same driving path group entering the main intersection are the same and the driving paths in the same driving path group do not conflict with each other.

[0087] Note:

[0088] Intersection: where multiple roads intersect;

[0089] Road segment: The portion of road between two intersections;

[0090] Lane: A specific driving area on a roadway that is designated for vehicles;

[0091] Driving path: the path formed by connecting one or more valid paths end to end when driving from the main intersection or from the intersection into the constructed intersection, and driving out of the constructed intersection from the main intersection. The valid path is the path obtained by dividing the main intersection into a single intersection, and the path to the main intersection obtained by dividing the secondary intersection into a single intersection. Represents a collection of driving paths.

[0092] The driving path group is the second path group and the first path group not connected to the local path group;

[0093] The first path group is used to indicate the path merging result corresponding to the entry section and the exit section being both located at the main intersection;

[0094] The second path group is used to indicate the path merging result corresponding to the entry section being located at the secondary intersection and the exit section being located at the primary intersection, that is, in this embodiment, for the secondary intersection, only the driving path from the secondary intersection to the primary intersection is considered;

[0095] When the constructed intersection only contains the main intersection, the first path group is used as the driving path group. Figure 2 The main intersection in the driving path group set is composed of the first path group n corresponding to the main intersection 1 to n 11 constitute;

[0096] When the constructed intersection includes a main intersection and a secondary intersection, the second path group and the first path group not connected to the local path group are used as the driving path group. Figure 2 As an example, the constructed intersection shown in FIG. 1 is a driving path group set, and its corresponding driving path group set is composed of the first path group n 1 to n 5 、n 9 to n 11 , and the second path group n 6a 、n 6b 、n 7a 、n7b 、n 8a 、n 8c constitute.

[0097] The specific method for obtaining the driving path group is as follows:

[0098] A110, obtaining a first path and a first path group;

[0099] A path whose incoming section and outgoing section are both located at the main intersection is taken as a first path, and each first path is merged to obtain a first path group.

[0100] One first path belongs to only one first path group.

[0101] Those skilled in the art may set the merging rules according to actual needs, so as to satisfy that the road sections corresponding to the first paths in the same first path group entering the main intersection are the same and the first paths in the same first path group do not conflict with each other.

[0102] That is, the main intersection is treated as a single intersection for path segmentation, all paths at the main intersection, ie, first paths, are obtained, and the paths are merged based on the conflict relationship between the first paths, and the obtained path group is used as the first path group.

[0103] use represents the set of valid paths of a single intersection, that is, when the main intersection is treated as a single intersection for path segmentation, the first path obtained is the corresponding valid path;

[0104] A valid path p in a single intersection consists of a section a entering the single intersection and a section b leaving the single intersection, expressed as (a, b), in the order of driving direction.

[0105] For a single intersection, there are two valid paths It can also be written as The conflict relationship can be directly determined based on the intersection design layout diagram, where for the merging path pair, a≠c but b=d, and they are considered not to conflict with each other.

[0106] In this embodiment, a set of valid path groups can also be used to represent the single intersection I. For example, when the single intersection is a main intersection, a set of the first path group can be used to represent the main intersection.

[0107] For two valid paths If the road sections entering the corresponding single intersection are the same and there is no conflict between them, they can be classified into the same valid path group u∈I;

[0108] If the set of valid path groups is represented as I = {p 0 , p 1, ..., p n}, for two different valid path groups p in a single intersection i , p j ∈I, i≠j, there is Moreover, there are That is, each valid path in a single intersection belongs to and must belong to a certain valid path group; and a valid path group is also the smallest unit controlled by the same signal at the single intersection.

[0109] Those skilled in the art may set the rules for path merging according to the specific form and layout of the intersection and on the basis of the above principles, and merge the valid paths controlled by the same signal phase into one valid path group;

[0110] For example:

[0111] The valid paths with the same entry and exit sections of the intersection are grouped into the same valid path group;

[0112] Paths occupying the same entry lane are classified into the same valid path group;

[0113] The straight and right-turn paths of the same entry section are merged into the same valid path group.

[0114] A120, obtaining a second path group;

[0115] In this embodiment, the path whose incoming section is located at the secondary intersection and whose outgoing section is located at the main intersection is recorded as the second path;

[0116] Path merging is performed based on the conflict relationship between the second paths to obtain a second path group.

[0117] A second path can be composed of several valid paths connected end to end, starting from the first secondary intersection entering the constructed intersection and ending at the last primary intersection leaving the set, including all valid paths passed;

[0118] For example, in constructing an intersection, there is a valid path from segment a to segment b. and a valid path from segment b to segment c Then, a second path that enters the secondary intersection from segment a, passes segment b, and leaves the main intersection from segment c is expressed as Represents the set of all driving paths.

[0119] A121, splitting each secondary intersection into a single intersection, and obtaining a local path corresponding to each secondary intersection heading to the main intersection;

[0120] From the intersection only the paths heading to the main intersection are considered;

[0121] When the intersection is split as a single intersection, the path to the main intersection is taken as the valid path and recorded as the local path.

[0122] For the driving route entering the connecting section between the secondary intersections, the vehicle needs to turn and divert in advance so that it can directly enter the target lane that cannot be changed (such as left turn, straight and right turn) after reaching the connecting section; considering the path conflict caused by diversion in the secondary intersection, a path that crosses the secondary intersection and enters the ultra-short connecting section is subdivided into a path group b consisting of the section a entering the secondary intersection and the connecting section reached (i.e., the local path group of the downstream intersection) to obtain the corresponding local path, which is expressed as The order is the driving direction.

[0123] A122, merging each pair of local paths corresponding to the intersections to obtain a corresponding local path group;

[0124] The local paths in the same local path group do not conflict with each other;

[0125] The intersection is regarded as a single intersection, and paths are merged based on the conflict relationship between its valid paths, that is, the local paths, to obtain the corresponding valid path group, which is recorded as the local path group.

[0126] A123. Based on the first path group, connect and merge the first path group and each local path group to obtain a corresponding second path group.

[0127] That is, the driving path group for constructing the intersection is divided based on the first path group of the main intersection.

[0128] Preferably, in this embodiment, through the design of the local path groups, starting from the secondary intersection farthest from the main intersection, the corresponding first path group and each local path group are connected end to end according to the driving direction toward the main intersection to form a plurality of second path groups;

[0129] Finally, the second path group and the first path group not connected to the local path group are used as the driving path group.

[0130] Reference Figure 2 , Figure 2 The n indicated in 1 to n 11 The first path group corresponding to the main intersection, n a to n c is the local path group corresponding to the intersection;

[0131] According to the driving direction toward the main intersection, based on the first path group, the corresponding first path group and the local path group are connected end to end to form a corresponding second path group n 6a , n 6b, n 7a , n 7b , n 8a , n 8c , such as path group n 6a Indicates that it contains the local path group n a Enter from Intersection I 1 , and then by the local path group n 6 Enter the main intersection I 0 The second path group of the path;

[0132] Based on the second path group obtained above and the first path groups of the remaining unconnected local path groups, a set of driving path groups V = {n 1 , n 2 , n 3 , n 4 , n 5 , n 6a , n 6b , n 7a , n 7b , n 8a , n 8c , n 9 , n 10 , n 11}.

[0133] A200, determining the conflict relationship between each driving path group, and constructing an undirected graph based on the conflict relationship to obtain the intersection model;

[0134] Use G:=(V, E) to represent the intersection model;

[0135] V is a set consisting of a finite number of elements, whose elements are called nodes;

[0136] The set consisting of two nodes in V is called an edge, and E represents the set of edges; if the edge {i, j}∈E connects nodes i, j∈V, then i and j are called the endpoints of the edge;

[0137] In this embodiment, when constructing the intersection model, the node represents the driving path group, and the edge represents the non-conflicting relationship between the driving path groups, that is, the driving path groups corresponding to the two connected nodes represented by the edge do not conflict with each other.

[0138] A210, Conflict Relationship:

[0139] When the constructed intersections only include the main intersections, the conflict relationship between the driving path groups is determined based on the conflict relationship between the first path groups.

[0140] When the constructed intersection includes a main intersection and a secondary intersection, the conflict relationship between the driving path groups is determined based on the conflict relationship between the first path groups and the conflict relationship between the local path groups;

[0141] That is, the conflict relationship of the driving path group can be determined by the conflict relationship between all valid path groups that constitute the two driving paths; specifically, the two driving paths are represented as l = (l 0 , l 1 ,...l i ...l n-1 ), s=(s 0 ,s 1 ,...s j ...s m-1 ), then for all i=0, 1, .., n-2 and j=0, 1, ..., m-2, (l i , l i+1 )∈u,(s j ,s j+1 )∈v, if the valid path groups u and v do not conflict with each other, it means that the two driving paths do not conflict with each other; that is, for all valid paths of single intersections contained in the driving path, the valid path groups to which they belong do not conflict with each other.

[0142] The following example illustrates the method of determining the conflict relationship between two driving path groups:

[0143] A211, predetermining the conflict relationship between the first path groups corresponding to the main intersection;

[0144] From the above, we can see that for a valid path group u, v∈I at a single intersection, the valid path group pair {u, v} conflicts with each other if and only if there exists a valid path p∈u, q∈v such that the valid path pair {p, qq} conflicts with each other;

[0145] However, when two first paths conflict, it is determined that the first path groups to which the two first paths belong conflict;

[0146] Alternatively, when there are conflicting first paths in two first path groups, it is determined that the two first path groups conflict.

[0147] A212. Determine in advance the conflict relationship between the local path groups corresponding to each slave intersection:

[0148] As above, when two local paths in a sub-intersection conflict, it is determined that the local path groups to which the two local paths in the sub-intersection belong conflict;

[0149] Alternatively, when conflicting partial paths exist in two partial path groups from the same intersection, it is determined that the two partial path groups conflict.

[0150] A213, determining the conflict relationship between two driving path groups;

[0151] When two driving paths conflict with each other, it is determined that the second driving path groups to which the two driving paths belong conflict with each other.

[0152] Taking the second path as a driving path as an example, a second path includes a first path and at least one partial path. Based on the first path, the first path group to which it belongs can be known, and based on the partial path, the partial path group to which it belongs can be known;

[0153] The first path groups and the local path groups corresponding to the two second paths are compared one by one based on the intersection. When there are conflicting first path groups and / or local path groups, it is determined that the two second paths conflict.

[0154] Alternatively, when there is a conflict between first path groups located at the same main intersection in the two driving path groups, and / or there is a conflict between local path groups located at the same secondary intersection, it is determined that the two driving path groups conflict.

[0155] The specific steps of constructing the intersection model are:

[0156] A221. Combine the driving path groups in pairs to generate a plurality of undirected pairs, and obtain a first undirected pair set;

[0157] Based on the set V of driving path groups established previously, a first undirected pair set K consisting of all driving path groups in the set V is constructed.

[0158] A222. Based on the conflict relationship, the two conflicting driving path groups are made to form an undirected pair to obtain a conflicting path group pair, and a second undirected pair set is constructed based on the obtained conflicting path group pair;

[0159] Based on the previously established set V of driving path groups, a second undirected pair set of conflicting path group pairs in set V is constructed.

[0160] In this embodiment, an undirected graph model for constructing conflict path pairs is also constructed.

[0161] In the undirected graph model In , each node represents a set of driving path groups, and the edge between two nodes represents the conflict between the path groups corresponding to the two connected nodes;

[0162] by Figure 2 Taking the constructed intersection shown in the figure as an example, the driving path group set corresponding to the constructed intersection is:

[0163] V2{n 1 , n 2 , n 3 , n 4 , n 5 , n6 a,n 6b , n 7a , n 7b , n 8a , n 8c , n 9 , n 10 , n 11};

[0164] The constructed undirected graph model like Figure 3 As shown, the conflicting nodes are connected by dashed lines; 0 Path group n that goes straight from north to south 10 , which is combined with the path group n that includes going from west to east, going straight left and turning right 1 , including the path group n that turns left from south to north 2 , including the path group n that goes straight from east to west 7a 、n 7b conflict.

[0165] A223, obtaining the complement of the second undirected pair set in the first undirected pair set to obtain a third undirected pair set; the undirected pairs in the third undirected pair set are non-conflicting path pairs;

[0166] That is, the second undirected pair set corresponding to the conflicting path pair is removed from the first undirected pair set consisting of all driving path pairs to determine the non-conflicting path pair.

[0167] The third undirected pair set is the edge set E in the intersection model, which can remove the second undirected pair set corresponding to the conflicting path groups from the first undirected pair set K composed of all driving path groups. Get, that is Where K = {{u, v}: u, v∈V∧u≠v}.

[0168] A224. Construct the intersection model based on the third undirected pair set.

[0169] From the above, we can see that the intersection model

[0170] Figure 2 The intersection model corresponding to the constructed intersection shown is as follows Figure 4 As shown, non-conflicting nodes are connected by solid lines; 0 Path group n from west to east, straight left and right turn 1 , which is only associated with path group n in the entire constructed intersection 4 , n 5 , n 8a , n 8c , n 11 There is no conflict between them.

[0171] A300, extracting the local maximum complete subgraph of the intersection model, and determining a path group set corresponding to the local maximum complete subgraph based on the driving path groups corresponding to each local maximum complete subgraph;

[0172] For each local maximum complete subgraph, all corresponding path groups do not conflict with each other and can be regarded as a phase.

[0173] For a given undirected graph G: = (V, E), if That is, all nodes in G are connected to each other, so G is called a complete graph; similarly, given an undirected graph G: = (V, E) and its subgraphs If there is more than one element in V′, then That is, all nodes in G′ are connected to each other, so G′ is called a complete subgraph of G, also called a clique; given an undirected graph G: = (V, E) and its complete subgraph If not present is a complete subgraph of G, then G′ is called the local maximum complete subgraph of G, also called the maximal clique.

[0174] In this embodiment, the nodes in the intersection model G are checked one by one to determine the local maximum complete subgraph consisting of only two-to-two connected nodes, and then all the local maximum complete subgraphs are obtained according to the different constituent nodes to obtain the set of local maximum complete subgraphs Φ(G);

[0175] Figure 4 All local maximum complete subgraphs corresponding to the intersection model G shown are as follows Figure 5 As shown, there are 11 in total. In each local maximum complete subgraph, all nodes (driving path groups) are connected in pairs.

[0176] Based on the nodes of the local maximum complete subgraph, the corresponding path group set is determined, referring to Figure 5 In the graph (1) in the local maximum complete subgraph, the nodes of the subgraph correspond to the driving path group n. 4 、n 5 、n 8a 、n 8c 、n 9 、n 10 and n 11 , then the above driving path group constitutes the path group set of the local maximum complete subgraph.

[0177] A400, generating a corresponding basic control scheme based on the path group set;

[0178] The basic control scheme includes a plurality of phases, and the phases correspond to the path group sets one by one, that is, each local maximum complete subgraph can be used as a phase.

[0179] The path group set is a set of simultaneously passable path groups, which can indicate the traffic flow of the passing state in the corresponding phase;

[0180] The path group set includes several driving path groups;

[0181] In the current phase;

[0182] The traffic status of the driving path group belonging to the corresponding path group set is pass, that is, the driving path group will enter the green light period based on the preset time configuration data;

[0183] The traffic status of the driving path group that does not belong to the path group set is prohibited and the red light will remain.

[0184] Those skilled in the art can set the order between the phases and the time configuration data corresponding to each phase according to the phases provided by the basic control scheme;

[0185] The time configuration data includes a green light reference duration and may also include a green light reference interval. The green light reference duration is used to indicate the green light period of the corresponding phase, and the green light reference interval is used to indicate the interval duration corresponding to entering the next phase from the current phase, that is, after the green light period ends, the corresponding yellow light and red light periods in the current phase.

[0186] Since the local maximum complete subgraph corresponds to the largest number of non-conflicting combinations of driving path groups, this embodiment can make each phase contain all combinations of as many non-conflicting path groups as possible through the design of the local maximum complete subgraph, thereby providing the most paths with the opportunity to pass through the intersection in the same time period.

[0187] Under the condition of determining the phase, those skilled in the art may sort and time the phases according to actual needs to generate a corresponding basic control scheme, which is not described in detail in this embodiment.

[0188] In summary, this embodiment proposes a construction intersection model based on an undirected graph, and determines a basic control scheme based on the intersection model, divides the driving path groups from the perspective of ensuring the freedom of signal control, so that the intersection model is free from the limitations of the intersection layout and can be compatible with and coordinate adjacent ultra-short spacing intersections; the intersection model uses an undirected graph to clearly construct the conflict relationship between the driving paths of the intersection, and extracts all combinations of path groups that can be used at the same time, which helps to improve the control flexibility and applicability of the model, and provides a reference for the design and optimization of traffic signal control.

[0189] The invention discloses an intersection signal control method, which is used for dynamically adjusting the traffic signal of the constructed intersection.

[0190] As an implementable method, it is used to dynamically adjust the traffic signal corresponding to the main intersection in the constructed intersection at the current phase based on the basic control scheme and traffic demand conditions;

[0191] Reference Figure 6 , including the following steps:

[0192] B100, determining a candidate path group for a signal to be switched;

[0193] The candidate path group includes a first candidate path group and a second candidate path group;

[0194] The first candidate path group is a driving path group corresponding to the state of the main intersection switching from pass to prohibition when switching from the current phase to the next phase, that is, the pass signal needs to switch from green light to red light;

[0195] The second path group is a driving path group at the main intersection where the state at the main intersection is switched from prohibited to allowed when switching from the current phase to the next phase, that is, the traffic signal needs to be switched from red light to green light.

[0196] In this embodiment, based on the path group set corresponding to each phase in the basic control scheme, the candidate path group of the signal to be switched is determined, and the specific steps are as follows:

[0197] B110, obtaining a first path group corresponding to the main intersection;

[0198] The first path group is a path group corresponding to a path whose incoming section and outgoing section are both located at the main intersection.

[0199] B120, obtaining a path group set corresponding to the current phase and the next phase;

[0200] B130, based on the two path group sets, respectively judging the state change of each first path group, and determining a candidate path group based on the obtained state change results;

[0201] Matching the first path group with the two path group sets, and determining a state change of the first path group based on the matching result;

[0202] In the single intersection scenario, all driving path groups are the first path group;

[0203] In a multi-intersection scenario, the driving path group is a first path group or a second path group, and the second path group includes a first path group and a plurality of local path groups;

[0204] Therefore, in this embodiment, the situation where the first path group belongs to the path group set includes:

[0205] is a driving path group in the corresponding path group set, that is, the first path group exists in the corresponding path group set;

[0206] The driving path group in the corresponding path group set is included, that is, the corresponding path group set has a second path group including the first path group.

[0207] Specifically:

[0208] B131. When the first path group belongs to the path group set corresponding to the current phase and does not belong to the path group set corresponding to the next phase, the first path group is used as a first candidate path group;

[0209] At this time, the traffic signal of the first path group will switch from the green light of the current phase to the red light of the next phase.

[0210] B132. When the first path group does not belong to the path group set corresponding to the current phase but belongs to the path group set corresponding to the next phase, the first path group is used as a second candidate path group;

[0211] At this time, the traffic signal of the first path group will switch from the red light of the current phase to the green light of the next phase.

[0212] B133. When the first path group belongs to the path group sets corresponding to both the current phase and the next phase, the traffic status of the first path group remains open, and the traffic signal remains a green light signal.

[0213] B134. When the first path group does not belong to the path group set corresponding to the current phase and the next phase, the traffic status of the first path group remains prohibited, and the traffic signal remains a red light signal.

[0214] B200, performing one or more early termination judgments before the end of the green light period corresponding to each first candidate path group, and terminating the green light period corresponding to the first candidate path group in advance based on the obtained judgment results;

[0215] The green light reference duration of the current phase is determined based on the preset time configuration data. Those skilled in the art can set the judgment trigger duration according to actual needs based on the green light reference time. When the duration of entering the green light period reaches the judgment trigger duration, one or more early termination judgments are performed according to the preset rules;

[0216] For example:

[0217] Directly set the judgment trigger duration;

[0218] Set the advance detection time so that the green light reference time minus the advance detection time can obtain the corresponding judgment trigger time.

[0219] The early termination judgment determines whether to terminate the green light period in advance by detecting the vehicle traffic demand corresponding to the first candidate path group, that is, when it is detected that there is no vehicle traffic demand corresponding to the first candidate path group, the road right end time corresponding to the first candidate path group, that is, the time when the green light ends, is determined based on a preset rule;

[0220] Those skilled in the art may utilize inductive sensors, cameras, and the like to detect the traffic demand conditions corresponding to the first candidate path group. The measurement range may be adjusted according to the length of the road section. For example, in this embodiment, induction coils are arranged at the starting position of each first path group where the lane cannot be changed and at the stop line position before the intersection. When the green light duration reaches the corresponding judgment trigger duration, the induction coils are used to measure whether there are vehicles in the corresponding non-changeable lane area. If there are no vehicles, it is determined that there is no traffic demand. Otherwise, it is determined that there is traffic demand. This specification does not limit it in detail.

[0221] The specific steps of ending the green light period corresponding to the first candidate path group in advance based on the obtained judgment result are:

[0222] B210, when the first candidate path group has a traffic demand, it is determined that no adjustment is made, and the right-of-way end time is determined based on the green light reference duration;

[0223] That is, the green light period of the first candidate path group is executed based on the green light reference duration.

[0224] Those skilled in the art may set one or more early termination judgments;

[0225] When multiple early end judgments are set, after the judgment triggering time is reached, periodic judgments are performed based on the preset judgment interval until the green light period ends;

[0226] This solution is only applicable to single intersection scenarios.

[0227] When an early termination judgment is set, the early termination judgment is only performed when the judgment triggering duration is reached;

[0228] This solution reserves time for coordinated control of secondary intersections, so it is suitable for single-intersection and multi-intersection scenarios.

[0229] B220. When there is no traffic demand for the first candidate path group, it is determined to end early. At this time, the first candidate path group is advanced to the corresponding road right end time and enters the interval period.

[0230] The interval period is the yellow light and red light period entered after the green light of the current phase ends.

[0231] For a solution in which multiple early termination judgments are made, the right-of-way termination time may be determined based on the time of early termination judgment.

[0232] In this embodiment, an advance switching duration is preset, and a reference end time of the green light is determined based on a reference green light duration. A right of way end time is determined based on the end reference time and the advance switching duration. When there is no traffic demand for the first candidate path group, it is determined to end in advance. At this time, the green light period ends at the right of way end time, that is, the right of way end time is used as the signal switching time.

[0233] Note that the advance switching duration is shorter than the advance detection duration.

[0234] B300, respectively performing early switching judgment on each second candidate path group, and making the corresponding second candidate path group enter the green light period in advance based on the obtained judgment result;

[0235] When the first candidate path group conflicting with the second candidate path group ends the green light in advance, the second candidate path group may also be switched to the green light in advance.

[0236] That is, the first path group in the next phase obtains the right of way after the green light interval time of all conflicting path groups in the current phase ends, and the switching signal is green.

[0237] The step of making an early switching judgment on the target second candidate path group includes:

[0238] B310. Acquire a first candidate path group that conflicts with the second candidate path group at the main intersection, and obtain a third candidate path group.

[0239] B320. Obtain the green light interval time between the second candidate path group and each third candidate path group;

[0240] The green light interval is used to indicate the interval time required to switch from the corresponding third candidate path group to the second candidate path group.

[0241] The green light interval time is used to indicate the safe interval time for the corresponding intersection to clear the traffic flow in the previous phase and enter the traffic flow in the next phase without conflict. That is, it is used to ensure that when the green light corresponding to the next phase is switched, there are no conflicting vehicles passing through the corresponding intersection.

[0242] The green light interval can be a fixed value or a floating value.

[0243] B321, the green light interval is a fixed value;

[0244] The preset time configuration data includes a green light reference interval, and the green light interval time is determined based on the green light reference interval;

[0245] For example:

[0246] The green light reference interval is a green light interval time, and all green light switching between the first path groups refers to the green light interval time;

[0247] The green light reference interval includes a plurality of green light interval times, so that all first path groups are combined in pairs to form a plurality of path group pairs, and the first path group pairs correspond to the green light interval times one by one. In actual application, the green light interval times corresponding to the two first path groups to be switched are queried from the pre-configured green light reference interval;

[0248] Those skilled in the art may set the green light reference interval according to actual needs, and this specification does not limit it in detail.

[0249] B322, the green light interval is a floating value;

[0250] Recording two first path groups to be switched as a first switching path group and a second switching path group respectively;

[0251] The calculation method of the green light interval time corresponding to switching from the first switching path group to the second switching path group is:

[0252] C10, acquiring all conflicting path pairs in the first switching path group and the second switching path group, and obtaining corresponding candidate path pairs;

[0253] The candidate path pair includes a conflicting first switching path and a second switching path, the first switching path belongs to the first switching path group, and the second switching path belongs to the second switching path group.

[0254] When the current phase switches to the next phase, the traffic state of the first switching path will switch from pass to prohibit, and the traffic state of the second switching path will switch from prohibit to pass.

[0255] C20. Calculate the path interval time corresponding to each candidate path pair, and use the maximum value of the path interval time as the green light interval time.

[0256] The path interval time is used to ensure that when the incoming traffic corresponding to the second switching path enters the conflict point of the corresponding intersection, the cleared traffic corresponding to the first switching path has left the conflict point of the intersection.

[0257] The green light interval time required for the first switching path group u to switch to the second switching path group v The value of is:

[0258]

[0259] in, represents the path interval time corresponding to switching from the first switching path p to the second switching path q;

[0260] That is, the green light interval time of the conflicting path pair is the maximum value of the path interval times of all conflicting path pairs in the path pair.

[0261] The method for calculating the path interval time corresponding to each candidate path pair is:

[0262] C21. Obtaining the vehicle start time and clearing time for clearing the traffic flow corresponding to the first switching path;

[0263] The vehicle start time is a reference value set based on the traffic flow type and turning type of the cleared traffic flow. In this embodiment, the vehicle start time is 3s for straight-moving motor vehicles, 2s for turning motor vehicles, 1s for non-motor vehicles, and 3s-7s (determined by the maximum speed limit of the road) for buses. Those skilled in the art can set the vehicle start time according to actual conditions.

[0264] The clearing time is used to indicate the time required for clearing the traffic flow to leave the corresponding conflict point;

[0265] In this embodiment, the clearing time is equal to the ratio of the clearing distance to the speed of clearing the traffic flow, and the clearing distance is the sum of the distance from the stop line to the conflict point on the clearing traffic flow path and the vehicle length.

[0266] C22. Obtaining the entry time of the incoming vehicle flow corresponding to the second switching path;

[0267] The entry time is used to indicate the time required for the incoming vehicle flow to reach the conflict point;

[0268] The entry time is equal to the ratio of the distance from the stop line to the conflict point on the path of the entering vehicle flow to the speed of the entering vehicle flow.

[0269] Note: The speeds for clearing and entering traffic can be determined based on vehicle speed limits, mean speeds, or speed distribution.

[0270] C23. Calculate and obtain a corresponding path interval time based on the vehicle start time, the clearing time, and the entry time.

[0271] In this embodiment, the calculation formula of the path interval time is:

[0272] t int =t ptn +t clr -t app

[0273]

[0274] in:

[0275] t int is the path interval time;

[0276] t pth The vehicle start time;

[0277] t clr To clear the time;

[0278] t app The entry time;

[0279] S c The distance from the stop line to the conflict point on the path corresponding to clearing the traffic flow;

[0280] L is the length of the vehicle, which can be a preset value;

[0281] V c The speed to clear the traffic can be determined based on the vehicle speed limit, the mean speed, or the speed distribution;

[0282] S a is the distance from the stop line to the conflict point on the path corresponding to the incoming traffic flow;

[0283] V a The speed of entering the traffic flow can be determined based on the vehicle speed limit, the average speed or the speed distribution.

[0284] As an implementable method, a spacing configuration model is constructed based on the intersection model;

[0285] The interval configuration model generates a corresponding interval time matrix based on the calculation formula of the path interval time, and the interval time matrix includes the green light interval time corresponding to each undirected pair in the first undirected pair set;

[0286] In actual use, the corresponding green light time interval may be extracted from the interval time matrix according to the two driving path groups to be switched.

[0287] by Figure 2 Taking the constructed intersection shown in the figure as an example, an interval configuration model is constructed based on the first non-relative set of the constructed intersection and the intersection model:

[0288]

[0289] Where: M int It is an interval configuration model, and its output interval time matrix contains the green light interval time corresponding to any two current driving path groups.

[0290] Note: From the above, we can see that Represents the driving path group n i Switch to driving route group n j Green light interval time; In the above interval configuration model, if i = j, or n i With n jThere is no conflict between them, and the calculation of such driving path pairs can be directly ignored, such as directly set to 0.

[0291] Furthermore, the yellow light time can be dynamically adjusted based on the calculated green light interval time;

[0292] The green light interval generally includes the yellow light time and the full red time; the yellow light time t amb Determined by the vehicle speed limit and must satisfy t pth +t clr ≥t amb +1, so that the car that cannot stop at the yellow light when the signal changes will not bring conflict risk to the traffic flow in the next phase, generally 3s-5s.

[0293] In summary, this embodiment calculates the green light interval time with the minimum granularity at the intersection, that is, the green light interval time required for each conflict point, which can be used as a safety time reference for flexible scheduling of the body path group during phase switching; in addition, this green light interval time corresponds to the highest efficiency limit for eliminating intersection path conflicts, and does not reserve a safety margin, which can be appropriately increased according to actual conditions in the application.

[0294] B330. When the interval time periods corresponding to the third candidate path groups all reach the corresponding green light interval time, the state of the second candidate path group is switched to pass.

[0295] That is, the first path groups conflicting with the second candidate path group all end their corresponding green light intervals, and the traffic signal corresponding to the second candidate path group can be switched from red to green in advance.

[0296] At this time, the right-of-way activation time of the second candidate path group can be determined based on the right-of-way stop time and the green light interval time corresponding to each third candidate path group. The right-of-way activation time also belongs to the signal switching time.

[0297] On the premise that the composition and switching time of the next phase are given, that is, knowing the basic control scheme, this embodiment concretizes the road right start and stop time (road right start time, road right end time) of the relevant driving path group when the phase is switched as the road right start and stop time of each driving path group in the current phase and the next phase, and implements it in the signal switching of the specific single intersection path group; for the main intersection, based on the given basic control scheme, the traffic conditions on the first path group within a certain time and space range before the end of the current phase are measured, and the road right start and stop time corresponding to the first path group is adjusted according to whether there is a vehicle traffic demand, so as to realize dynamic control of traffic signals and effectively alleviate traffic pressure.

[0298] As another possible implementation method, when the constructed intersection includes a secondary intersection, the traffic signals corresponding to the secondary intersections are coordinated and controlled based on the dynamic adjustment of the above-mentioned candidate path groups.

[0299] Coordinate the start and stop time of the right of way of the local path groups between adjacent secondary intersections to avoid the overflow of queued vehicles in ultra-short sections and the waste of green light time at the main intersection due to late arrival of vehicles. Therefore, based on the signal change of the first path group at the main intersection, coordinate the signals of the relevant local path groups with dominant traffic flow in the upstream secondary intersections in turn;

[0300] In this embodiment, the adjusted path group is used as the target path group. The adjusted path group includes:

[0301] The first candidate path group;

[0302] The second candidate path group;

[0303] Upstream path group.

[0304] The specific steps of coordinating and controlling the traffic signals from the intersection corresponding to the target path group are as follows:

[0305] B410, determining an upstream path group of the target path group;

[0306] B411, searching for a second path group including the target path group from the path group set corresponding to the corresponding phase;

[0307] When the target path group is the first candidate path group, searching for the second path group from the path group set corresponding to the current phase;

[0308] When the target path group is the second candidate path group, the second path group is searched from the path group set corresponding to the next phase.

[0309] B412: When a second path group including the target path group is found from the corresponding path group set, a corresponding upstream path group is extracted from each local path group of the second path group.

[0310] B413. When the second path group including the target path group is not found from the corresponding path group set, it is determined that there is no secondary intersection requiring coordinated control.

[0311] B420, adjusting the signal switching time of the upstream path group accordingly, and taking the upstream path group as a new target path group for coordinated control;

[0312] The signal switching time includes the right-of-way end time and the right-of-way start time;

[0313] For the selected second path group, starting from the main intersection (take i = 0), record T i is the estimated signal switching time of the target path group corresponding to intersection i, t i,i+1is the average travel time between intersection i+1 and the stop line of downstream intersection i, δ i，i+1 is the time parameter used to measure the proposed vehicle queue in the ultra-short section between intersection i+1 and i, δ′ i,i+1 is the clearing time of the existing vehicle queue in the ultra-short section between intersection i and i+1, where δ i，i+1 ,δ′ i,i+1 The value range is 0~t i,i+1 And it can be adjusted according to the actual average queue situation.

[0314] B421. When the target path group is a path group that ends the green light period in advance;

[0315] That is, the target path group is the first candidate path group or the corresponding upstream path group;

[0316] The storage time δ corresponding to the upstream path group based on the target path group i，i+1 and the time T at which the target path group is expected to end the green light period i Determine the time T when the green light period of the current upstream path group ends i+1 , T i+1 =T i -δ i，i+1 .

[0317] Note: The estimated end time of the green light period for each first candidate path group can be calculated based on the preset advance switching time and the green light reference time to determine the corresponding right of way end time.

[0318] B422. When the target path group is a path group for starting the green light period in advance;

[0319] That is, the target path group is the second candidate path group or the corresponding upstream path group;

[0320] The clearing time δ′ corresponding to the upstream path group based on the target path group i,i+1 and the time T at which the target path group is expected to enter the green light period i Determine the alternative time T for the current upstream path group to enter the green light period i+1 , T i+1 =T i -δ′ i，i+1 ;

[0321] The current upstream path group reaches the alternative time T i+1 , and when all conflicting path groups corresponding to the current upstream path group have reached the green light interval time, the current upstream path group is switched to the green light in advance.

[0322] Note:

[0323] The time when the second candidate path group enters the green light period can be estimated based on the green light interval time between the second candidate path group and the corresponding third candidate path groups to determine the corresponding right-of-way activation time.

[0324] In practical applications, based on historical traffic data, we can first select a driving path group with dominant traffic flow in each entrance section of the main intersection, and also take into consideration the driving path groups that share the same local path group of the main intersection and do not conflict with it; then, for the selected driving path group, based on the signal switching plan implemented at the main intersection, coordinate the signal switching time of the corresponding local path group in turn upstream from the intersection.

[0325] Furthermore, this embodiment coordinates and controls the local path groups corresponding to the corresponding slave intersections by predicting the signal switching time of the first path group corresponding to the main intersection. Therefore, the advance switching duration can be adjusted according to the slave intersections that need to be coordinated, which is required to be later than the measurement time and ensure that the coordinated switching time of the local path group of the most upstream slave intersection does not exceed the measurement time. The measurement time refers to the time for measuring the traffic demand and making an early termination judgment.

[0326] by Figure 2 Taking the constructed intersection shown as an example, a method for dynamically adjusting the traffic signal corresponding to the main intersection and coordinating and controlling the traffic signal corresponding to the secondary intersection is illustrated;

[0327] In this case:

[0328] Current phase correspondence Figure 5 Neutron graph (2), containing path group n 2 、n 3 、n 4 、n 5 、n 8a 、n 8c 、n 11 , the next phase to be switched corresponds to Figure 5 Neutron graph (5), containing path group n 2 、n 4 、n 5 、n 7b 、n 8c 、n 11 ;

[0329] The reference time of signal switching based on the basic control scheme is T p ;

[0330] In T p -τ time, the local path group n of the main intersection related to the current phase is obtained by measurement 2 、n 4 、n 5 、n 11There is traffic demand on some, and no traffic demand on others, and τ is the configured advance detection time.

[0331] In this regard, the signal switching judgment is performed on the first path group of the main intersection respectively:

[0332] (1) Path group n 2 、n 4 、n 5 、n 8c 、n 11 In both the current phase and the next phase, no switching signal is required, corresponding to the master and slave intersection local path group n 2 、n 4 、n 5 、n 8 、n c 、n 11 Still green light;

[0333] (2) Path group n 3 If the signal is not in the next phase and there is no traffic demand, the signal can be switched in advance, that is, at T p -τ′ enters the green light interval time τ′ is the configured advance switching duration, Indicates that from the first path group n 3 Switch to n 7 The corresponding green light interval time;

[0334] (3) Path group n 8a Not in the next phase and no traffic demand, because n 8 Still green (n 8c In the next phase), it is only necessary to switch in advance from the local path group n of the intersection a The signal at T p -τ′-δ 0，1 Always enter the green light interval δ 0，1 Indicates from intersection I 1 To the main intersection I 0 The storage time corresponding to the connecting section of p -τ′-δ 0，1 The time is the corresponding right of way end time. Indicates that from the local path group n a Switch to n b The corresponding green light interval time;

[0335] (4) Path group n 7b Only belongs to the next phase, and in the main intersection, its local path group n 7 With path group n 3 If they conflict with each other, then there are n 7 exist When the switch signal is green, that is, The time is n 7 The right-of-way start time, and in the intersection, its local path group n b With local path group n a If they conflict with each other, then there are n b exist When the switching signal is green, δ′ 0,1 Indicates from intersection I 1 To the main intersection I 0 The clearing time corresponding to the connecting section.

[0336] Figure 7 This is a schematic diagram of the signal switching time in this case, corresponding to the above path group n 3 、n 8a With n 7b The signal switching situation; among them, when measuring the main intersection path group n 3 、n 8 When there is no traffic demand, the signal is switched in advance to terminate the right of way and make n 7 Obtain the right of way in advance and coordinate the corresponding path group n from the intersection a With n b signal switching.

[0337] An intersection signal control system is used to execute the intersection signal control method described in any one of the above embodiments.

[0338] As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0339] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0340] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0341] The present invention is described with reference to the flowcharts and / or block diagrams of the method, terminal device (system), and computer program product according to the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0342] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0343] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable terminal device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0344] It should be noted that:

[0345] The "one embodiment" or "embodiment" mentioned in the specification means that the specific features, structures or characteristics described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "embodiment" appearing in various places throughout the specification do not necessarily refer to the same embodiment.

[0346] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0347] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different. Any equivalent or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. The technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for controlling intersection signals, for generating a corresponding basic control scheme for a constructed intersection, wherein the constructed intersection includes a main intersection, characterized in that: The following steps are involved: The driving paths of the constructed intersection are merged to obtain a plurality of driving path groups; the road sections corresponding to the driving paths in the same driving path group entering the main intersection are the same, and the driving paths in the same driving path group do not conflict with each other; Determine the conflict relationship between each driving path group, and construct an undirected graph based on the conflict relationship to obtain the intersection model; in the intersection model, the node represents the driving path group, and the edge represents that the driving path groups corresponding to the two connected nodes do not conflict with each other; Extracting the local maximum complete subgraph of the intersection model, and determining a path group set corresponding to the local maximum complete subgraph based on the driving path groups corresponding to each local maximum complete subgraph; A corresponding basic control scheme is generated based on the path group set, wherein the basic control scheme includes a plurality of phases, the phases correspond to the path group set one by one, and the path group set is used to indicate the traffic flow of the traffic state in the corresponding phase.

2. The intersection signal control method according to claim 1, characterized in that: The specific steps of constructing the intersection model are: Combine the driving path groups in pairs to generate a number of undirected pairs, and obtain a first undirected pair set; Based on the conflict relationship, the two conflicting driving path groups are made to form an undirected pair to obtain a conflicting path group pair, and a second undirected pair set is constructed based on the obtained conflicting path group pair; Obtaining the complement of the second undirected pair set in the first undirected pair set to obtain a third undirected pair set, wherein the undirected pairs in the third undirected pair set are non-conflicting path pairs; The intersection model is constructed based on the third undirected pair set.

3. The intersection signal control method according to claim 1 or 2, characterized in that: The driving path includes a first path, wherein the first path is a path in which both the entry section and the exit section are located at the main intersection; A driving path group is determined based on the first path group, where the first path group is a path group obtained by merging the first paths.

4. The intersection signal control method according to claim 3, characterized in that: The construction intersection also has at least one slave intersection; Each secondary intersection is treated as a single intersection for path segmentation, and a local path corresponding to each secondary intersection heading to the main intersection is obtained; Merge each pair of local paths corresponding to the intersections to obtain a corresponding local path group, where the local paths in the same local path group do not conflict with each other; Based on the first path group, connecting and merging the first path group and each local path group to obtain a corresponding second path group; The second path group and the first path group not connected to the local path group are used as a driving path group.

5. The intersection signal control method according to claim 4, characterized in that: When there is a conflict between first path groups located at the same main intersection and / or between local path groups located at the same secondary intersection in two driving path groups, it is determined that the two driving path groups conflict.

6. The intersection signal control method according to claim 5, characterized in that: When there are conflicting first paths in the two first path groups, it is determined that the two first path groups conflict; When there are conflicting local paths in two local path groups from the same intersection, it is determined that the two local path groups conflict.

7. A method for controlling intersection signals, for dynamically adjusting the traffic signals at an intersection, characterized in that: The constructed intersection includes a main intersection, and dynamically adjusting the traffic signal corresponding to the main intersection at the current phase based on a basic control scheme, wherein the basic control scheme is a basic control scheme generated according to any one of claims 1 to 6; The following steps are involved: Based on the path group set corresponding to the corresponding phase in the basic control scheme, determine the first candidate path group of the signal to be switched, the first candidate path group is the first path group corresponding to the state at the main intersection switching from pass to prohibition when switching from the current phase to the next phase, and the first path group is the path group corresponding to the path whose entry section and exit section are both located at the main intersection; Determine the green light reference duration of the current phase based on the preset time configuration data, and perform one or more early end judgments before the end of the green light period corresponding to each first candidate path group based on the green light reference duration; When the first candidate path group has a traffic demand, it is determined that no adjustment is made, and the right-of-way end time is determined based on the green light reference duration; When there is no traffic demand for the first candidate path group, it is determined to end early, and the first candidate path group is advanced to the corresponding right-of-way end time.

8. The intersection signal control method according to claim 7, characterized in that: Based on the path group set corresponding to the corresponding phase in the basic control scheme, determine the second candidate path group to be switched by the current signal, the second candidate path group being the first path group in which the state at the main intersection is switched from prohibited to pass when switching from the current phase to the next phase; The early switching judgment is performed on each second candidate path group respectively, specifically: Acquire a first candidate path group that conflicts with the second candidate path group at the main intersection, and obtain a third candidate path group; Acquire a green light interval time between the second candidate path group and each third candidate path group, where the green light interval time is used to indicate an interval time required to switch from the corresponding third candidate path group to the second candidate path group; When the interval time periods corresponding to the third candidate path groups all reach the corresponding green light interval time, the state of the second candidate path group is switched to pass.

9. The intersection signal control method according to claim 8, characterized in that: The calculation method of the green light interval time corresponding to switching from the first switching path group to the second switching path group is: Acquire all conflicting path pairs in the first switching path group and the second switching path group, and obtain corresponding candidate path pairs, wherein the candidate path pairs include the conflicting first switching path and the second switching path, the first switching path belongs to the first switching path group, and the second switching path belongs to the second switching path group; Calculate the path interval time corresponding to each candidate path pair, and take the maximum value of the path interval time as the corresponding green light interval time; The method for calculating the path interval time corresponding to each candidate path pair is: Obtaining a vehicle start time and a clearing time for clearing the traffic flow corresponding to the first switching path, wherein the vehicle start time is a reference value set based on the traffic flow type and the turning type for clearing the traffic flow, and the clearing time is used to indicate the time required for the clearing traffic flow to leave the corresponding conflict point; Acquire an entry time of an incoming vehicle flow corresponding to the second switching path, where the entry time is used to indicate a time required for the incoming vehicle flow to reach the conflict point; The corresponding path interval time is calculated based on the vehicle start time, the clearing time and the driving time.

10. The intersection signal control method according to any one of claims 7 to 9, characterized in that: The constructed intersection further comprises at least one slave intersection; The first candidate path group of the green light period to be ended early is used as the target path group; The green light end time of the upstream path group corresponding to the target path group is advanced, and the upstream path group is used as the new target path group to continue coordinated control.

11. The intersection signal control method according to any one of claims 7 to 9, characterized in that: The constructed intersection further comprises at least one slave intersection; The second candidate path group to be entered into the green light period in advance is used as the target path group; The green light start time of the upstream path group corresponding to the target path group is advanced, and the upstream path group is used as the new target path group to continue coordinated control.

12. An intersection signal control system, characterized in that: Used to execute the intersection signal control method described in any one of claims 1 to 11.

Images