A signal control method and control system based on queue vehicle number difference detection

Abstract

The application discloses a signal control method and control system based on queuing vehicle number difference detection, and belongs to the technical field of urban road traffic control. According to the queuing vehicle number difference of different flow directions, the green light time required for passing is calculated, and whether the intersection adjusts the release time and the release mode is judged in real time. When the green light time required for the 'east-west straight line-east-west left turn' mode is greater than the time required for the 'east single release-west single release' release mode, the east-west release mode in the cycle is adjusted to 'east single release-west single release', otherwise the release mode is 'east-west straight line-east-west left turn'; when the green light time required for the'south-north straight line-south-north left turn' mode is greater than the time required for the'south single release-north single release' release mode, the south-north release mode in the cycle is adjusted to'south single release-north single release', otherwise the release mode is'south-north straight line-south-north left turn'. The release time of each phase under all release modes is the green light time required for passing.

Description

Technical Field

[0001] This invention belongs to the field of urban road traffic control, specifically relating to a signal control method and system at intersections based on the detection of differences in the number of queuing vehicles in different directions. Background Technology

[0002] In recent years, traffic congestion in my country has become increasingly serious. Faced with highly unpredictable traffic flows, relying solely on fixed intersection signal timing schemes is now insufficient to meet the traffic demands of many intersections. To address this issue, intersection sensor-based control technology has emerged. This technology automatically adjusts the phase green light ratio by monitoring the traffic demand at each approach lane in real time, flexibly adjusting the green light time for each phase of the intersection, and has achieved some success. However, this technology still has certain shortcomings: adjusting the green light time of only one signal phase by sensing the traffic demand at the approach lanes can easily interfere with traffic flows in other directions at that phase. For example, when north-south through traffic is allowed, the demand for through traffic at the south entrance is high, while the demand at the north entrance is low. If the existing sensor-based control technology increases the green light time, the north entrance will be left empty; if the green light time is decreased or not adjusted, vehicles at the south entrance will queue multiple times, both reducing the intersection's traffic efficiency. Summary of the Invention

[0003] The purpose of this invention is to maximize the use of limited road resources and improve road segment traffic efficiency. To this end, a method and system are provided that utilizes a queuing vehicle count detection device to dynamically detect the number of queuing vehicles at each approach lane of an intersection and determine whether to adjust the release time and release method. Based on real-time monitoring of the differences in the number of queuing vehicles in different directions at the intersection, the release method and release time are adjusted simultaneously.

[0004] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0005] A signal control method based on detecting differences in the number of vehicles in a queue includes the following steps:

[0006] S1, RFID detectors are deployed at the intersection entrance to detect the number of queuing vehicles in each direction;

[0007] S2 detects the number of vehicles queuing for straight-through and left-turning traffic at the east and west entrances of the intersection, and calculates the time required for all queuing vehicles in each direction to pass through the intersection.

[0008] S3, calculate the shortest green light time G required to adopt the east-west straight-through-east-west left-turn traffic pattern. EW1 The green light time G required for the east-to-west single-pass release method EW2 ;

[0009] S4, compared to G EW1 and GEW2 The size of G EW1 ≤G EW1 , execute S5, otherwise execute S7;

[0010] S5, east straight line allows release, release time is g 1_5 , then enters 3s yellow light time, turn S6;

[0011] S6, east straight line prohibits release, east left turn allows release, release time is g 2_6 , then enters 3s yellow light time, turn S9;

[0012] S7, east straight line, left turn allows release, release time is g 1_2 , then enters 3s yellow light time, turn S8;

[0013] S8, east straight line prohibits release, west straight line, left turn allows release, release time is g 5_6 , then enters 3s yellow light time, turn S9;

[0014] S9, detects the queue vehicle number of north-south straight line, left turn of the intersection, calculates the time required for all queue vehicles to pass through the intersection;

[0015] S10, calculates the shortest green light time G SN1 required for taking north-south straight line-north-south left turn release mode, the green light time G SN2 required for east single release-west single release release mode;

[0016] S11, compares the size of G SN1 and G SN2 , if G SN1 ≤G SN2 , execute S12, otherwise execute S14;

[0017] S12, north-south straight line allows release, release time is g 3_7 , then enters 3s yellow light time, turn S13;

[0018] S13, north-south straight line prohibits release, north-south left turn allows release, release time is g 4_8 , then enters 3s yellow light time, turn S2;

[0019] S14, south straight line, left turn allows release, release time is g 1_2 , then enters 3s yellow light time, turn S15;

[0020] S15, south straight line prohibits release, north straight line, left turn allows release, release time is g 5_6 , then enters 3s yellow light time, turn S2;

[0021] Further, the four approaches of the intersection are provided with straight lanes 1, 3, 5, 7 and left-turn lanes 2, 4, 6, 8;

[0022] Further, at the four approaches of the intersection, queue vehicle number detector 9, queue vehicle number detector 10, queue vehicle number detector 11 and queue vehicle number detector 12 are respectively arranged to detect the queue vehicle number of each flow direction during the red light of the intersection approach, and left-turn flow guide lines 17, 18, 19 and 20 are arranged.

[0023] Further, the queue vehicle number j of each approach is detected k According to the driver reaction time τ, vehicle start delay T c , vehicle start acceleration a c , the length of the ith vehicle l i , and the vehicle spacing d, the time required for all the queue vehicles of each flow direction of the intersection to pass through the intersection is calculated, which is specifically:

[0024]

[0025] In the formula, k is 1-8, representing the eight flow directions of the intersection. Among them, 1 represents east straight; 2 represents east left turn; 3 represents south straight; 4 represents south left turn; 5 represents west straight; 6 represents west left turn; 7 represents north straight; 8 represents north left turn. For details, see Figure 1 .

[0026] Further, the release time of all flow directions should be no more than the maximum green light time set for the flow direction of the intersection When the phase time reaches , the next phase is automatically switched; the release time of all phases should be no less than the minimum green light time set for the intersection When it is calculated that the queue dissipation vehicles can be dissipated before , the green light time should be extended to Then switch to the next phase, which is specifically:

[0027]

[0028] Further, the minimum green light and maximum green light time calculation formula of each flow direction is:

[0029]

[0030]

[0031]

[0032] In the formula, g kk represents the actual green light time; L a Indicates the length of the pedestrian crossing at the entrance; L m Indicates the maximum detection length of the RFID detector; v p I indicates pedestrian crossing speed; L indicates the set yellow light duration; b Indicates the length of the left-turn guide line in that direction; R b Indicates the width of the left-turn lanes at each entrance; V m Indicates the speed limit for the road segment; int is the floor function; θ b This indicates the angle between the entrance lane and the corresponding exit lane for that flow direction. Specifically: θ2 represents the angle between the left-turn lane at the east entrance and the innermost exit lane at the south entrance; θ4 represents the angle between the left-turn lane at the south entrance and the innermost exit lane at the west entrance; θ6 represents the angle between the left-turn lane at the west entrance and the innermost exit lane at the north entrance; θ8 represents the angle between the left-turn lane at the north entrance and the innermost exit lane at the east entrance.

[0033] Furthermore, the release time for all phases should be determined based on the flow with the greatest traffic demand among all traffic directions in that phase. The release method should be determined based on the minimum green light time required to meet traffic demand using both symmetrical release and single-sided turn-by-turn release methods, specifically:

[0034] 1) East-west direction

[0035] The formula for judgment is:

[0036] g 1_2 =max(g1, g2)

[0037] g 5_6 = max(g5, g6)

[0038] g 1_5 =max(g1, g5 )

[0039] g 2_6 =max(g2, g6 )

[0040] M E-W =sign(G EW2 -G Ew1 )=sign[(g 1_5 +g 2_6 )-(g 1_2 +g 5_6 )]

[0041] M E-W When option 1 is selected, the east-west direction of the intersection adopts the "single-way passage from east to west" release method, with release times of g respectively. 1_2 g 5_6 M E-WWhen M = -1 or 0, the east-west direction of the intersection adopts the "east-west straight - east-west left turn" release mode, and the release times are g 1_5 , g 2_6 .

[0042] 2) South-north direction

[0043] The judgment formula is:

[0044] g 3_4 = max (g3, g4)

[0045] g 7_8 = max (g7, g8)

[0046] g 3_7 = max (g3, g7)

[0047] g 4_8 = max (g4, g8)

[0048] M S-N = sign (G SN2 -G SN1 ) = sign [(g 3_7 + g 4_8 ) - (g 3_4 + g 7_8 )]

[0049] M S-N When M = 1, the south-north direction of the intersection adopts the "single release of the south intersection - single release of the north intersection" release mode, and the release times are g 3_4 , g 7_8 ; M S-N When M = -1 or 0, the south-north direction of the intersection adopts the "south-north straight - south-north left turn" release mode, and the release times are g 3_7 , g 4_8 .

[0050] Further, at the four exit lanes of the intersection, LED display screens 13, 14, 15 and 16 are arranged to face the entrance lane for prompting the driver. East-west direction: when the intersection performs "east-west straight - east-west left turn", the east-west direction display screens 13 and 15 display "straight vehicle allowed to pass" and "left turn vehicle allowed to pass" in sequence; when the intersection performs "east single release - west single release", the display screen 15 displays "east all vehicles allowed to pass" during the east single release, and the display screen 13 displays "west all vehicles allowed to pass" during the west single release; north-south direction: when the intersection performs "north-south straight - north-south left turn", the north-south direction display screens 14 and 16 display "straight vehicle allowed to pass" and "left turn vehicle allowed to pass" in sequence; when the intersection performs "south single release - north single release", the display screen 16 displays "south all vehicles allowed to pass" during the south single release, and the display screen 14 displays "north all vehicles allowed to pass" during the north single release. During the remaining time period, each display screen displays "prohibited to pass".

[0051] A signal control system based on queue vehicle number difference detection, comprising:

[0052] An RFID detector, which detects the queue vehicle number at each flow direction entrance lane of the intersection in real time, and sends the detection data to the central signal system;

[0053] The central signal system analyzes the collected queue vehicle data to obtain a detection result, and sends the detection result to the traffic signal control machine;

[0054] The traffic signal control machine adjusts the release mode and release time of the intersection according to the analysis result of the central signal system, and sends the timing scheme execution result to the central signal system;

[0055] An electronic display screen, which is used to prompt the driver of each flow direction when to allow to pass through the intersection.

[0056] The beneficial effects of the present application are:

[0057] (1) The present application detects the queue vehicle number of each flow direction of the intersection, automatically adjusts the release mode and release time of the intersection through analysis and calculation, further improves the time utilization rate of the intersection, and avoids the phenomenon that the separate adjustment of the signal control time leads to the empty release or multiple queuing of the intersection, and reduces the traffic efficiency of the intersection.

[0058] (2) In the present application, the setting of the signal control time ensures the shortest green light time demand, controls the green light time length according to the queue vehicle number of all flow directions in the release phase instead of the queue length, ensures that all queue vehicles can pass through the intersection during the green light period, effectively controls the number of secondary queue vehicles of the intersection, and further reduces the intersection delay. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 Frame diagram of the signal control system of the present application;

[0060] Figure 2 Flow chart of the signal control method of the present application;

[0061] Figure 3 Field layout of the signal control system of the present application;

[0062] Figure 4 Schematic diagram of the signal control method of the present application.

[0063] In the figure: 1 - east exit straight lane, 2 - east exit left turn lane, 3 - south exit straight lane, 4 - south exit left turn lane, 5 - west exit straight lane, 6 - east exit left turn lane, 7 - north exit straight lane, 8 - north exit left turn lane, 9 - RFID detector one, 10 - RFID detector two, 11 - RFID detector three, 12 - RFID detector four, 13 - LED electronic display screen one, 14 - LED electronic display screen two, 15 - LED electronic display screen three, 16 - LED electronic display screen four, 17 - left turn guide line one, 18 - left turn guide line two, 19 - left turn guide line three, 20 - left turn guide line four, 21 - intersection signal light, 22 - street crossing zebra crossing one, 23 - street crossing zebra crossing two, 24 - street crossing zebra crossing three, 25 - street crossing zebra crossing four. DETAILED DESCRIPTION

[0064] The present application is further described below in conjunction with the accompanying drawings and specific embodiments, but the scope of protection of the present application is not limited thereto.

[0065] As Figure 1As shown, a signal control system based on the detection of differences in the number of queued vehicles includes RFID detectors, a central signal system, a traffic signal controller, and an electronic display screen. The RFID detectors, using road surface RFID counting detectors installed at the intersection's approach lanes, detect the number of queued vehicles in each direction in real time and send the detection data to the central signal system. The central signal system analyzes the collected queued vehicle detection data to obtain the detection results and sends them to the traffic signal controller. The traffic signal controller adjusts the intersection's traffic light release mode and release time based on the analysis results and sends the execution results of the release mode and release time to the central signal system. The electronic display screen provides driver operation prompts: When the intersection adopts an east-west traffic flow pattern of "east-west straight ahead - east-west left turn," the east-west display screen shows "Straight ahead vehicles are permitted to proceed" during the east-west straight ahead phase, and "Left turn vehicles are permitted to proceed" during the east-west left turn phase; when the intersection adopts an east-west traffic flow pattern of "east-west one-way," the west-west display screen shows "All vehicles at the east entrance are permitted to proceed" during the east-west one-way phase, and "All vehicles at the west entrance are permitted to proceed" during the west-west one-way phase. When the intersection adopts a "straight-through - left-turn" traffic release method in the north-south direction, the north-south display screen will show "straight-through vehicles are allowed to pass" during the straight-through period and "left-turn vehicles are allowed to pass" during the left-turn period. When the intersection adopts a "single-way south - single-way north" traffic release method in the north-south direction, the north display screen will show "all vehicles at the south entrance are allowed to pass" during the single-way south entrance period and "all vehicles at the north entrance are allowed to pass" during the single-way north entrance period.

[0066] like Figure 2 As shown, a signal control method based on the detection of differences in the number of vehicles in a queue includes the following specific steps:

[0067] Step (1): The east-west RFID detector detects the number of vehicles queuing for straight-through and left-turn traffic at the east-west entrance and calculates the time required for all vehicles queuing for straight-through and left-turn traffic at the east-west entrance to dissipate.

[0068] Step (2): Is the time required for the east-west direction to adopt the "east-west straight-east-west left turn" release method greater than the time required for the "east entrance single release-west entrance single release" release method? If yes, proceed to step (3); otherwise, proceed to step (4).

[0069] Step (3), the intersection executes "East mouth single release - West mouth single release" release mode. The intersection executes East mouth single release phase, the East entrance straight and left turn direction signal lamp displays green light, the West mouth electronic display screen displays "East mouth all vehicles are allowed to release", the East mouth single release green light time reaches threshold value, the West mouth single release phase is executed, the East entrance straight and left turn direction signal lamp displays red light, the West entrance straight and left turn direction signal lamp displays green light, the East mouth electronic display screen displays "West mouth all vehicles are allowed to release", the West mouth straight and left turn direction signal lamp and the like displays red light, step (5) is executed.

[0070] Step (4), the intersection executes "East and West straight - East and West left turn" release mode. The intersection executes East and West straight phase, the intersection East and West straight direction signal lamp displays green light, the East and West mouth electronic display screen displays "straight vehicle is allowed to release", the East and West straight green light time reaches threshold value, the East and West left turn phase is executed, the East and West straight direction signal lamp displays red light, the East and West left turn direction signal lamp displays green light, the East and West mouth electronic display screen displays "left turn vehicle is allowed to release", the East and West left turn green light time reaches threshold value, the East and West left turn direction signal lamp displays red light, step (5) is executed.

[0071] Step (5), the South and North direction RFID detector detects the queuing vehicle number of South and North entrance straight and left turn flow direction, and calculates the time required for all the queuing vehicles of South and North entrance straight and left turn to dissipate.

[0072] Step (6), whether the time required for the South and North direction to take "South and North straight - South and North left turn" release mode is greater than the time required for taking "South mouth single release - North mouth single release" release mode, if yes, step (7) is executed, otherwise, step (8) is executed.

[0073] Step (7), the intersection executes "South mouth single release - North mouth single release" release mode. The intersection executes South mouth single release phase, the South entrance straight and left turn direction signal lamp displays green light, the North mouth electronic display screen displays "South mouth all vehicles are allowed to release", the South mouth single release green light time reaches threshold value, the North mouth single release phase is executed, the South entrance straight and left turn direction signal lamp displays red light, the North entrance straight and left turn direction signal lamp displays green light, the South mouth electronic display screen displays "North mouth all vehicles are allowed to release", the North mouth single release green light time reaches threshold value, the North mouth straight and left turn direction signal lamp and the like displays red light, step (1) is executed.

[0074] Step (8): The intersection adopts the "north-south straight - north-south left turn" traffic release mode. The intersection implements the north-south straight phase, the north-south straight direction traffic light shows green, the north-south electronic display screen shows "straight vehicles are allowed to pass", after the north-south straight green light time reaches the threshold, the north-south left turn phase is implemented, the north-south straight direction traffic light shows red, the north-south left turn direction traffic light shows green, the north-south electronic display screen shows "left turn vehicles are allowed to pass", after the north-south left turn green light time reaches the threshold, the east-west left turn direction traffic light shows red, and step (1) is executed.

[0075] A signal control method based on the detection of differences in the number of vehicles in a queue is described in detail below:

[0076] 1. Install RFID detectors and left-turn guide lines

[0077] like Figure 3 , 4 As shown, RFID detector 1 (9), RFID detector 2 (10), RFID detector 3 (11), RFID detector 4 (12), and left-turn guide lines 1 (17), 2 (18), 3 (19), and 4 (20) need to be installed at all four entrances to the intersection. This is to detect the number of vehicles queuing in each direction at the intersection, and to calculate the time required for the queue to clear based on the number of vehicles queuing. The calculation formula is as follows:

[0078]

[0079] In the formula: j k This represents the number of vehicles queuing at each entrance lane, τ represents the driver's reaction time, and T represents the number of vehicles queuing at each entrance lane. c Indicates vehicle start-up delay, a c The vector represents the vehicle's starting acceleration, l represents the vehicle length, d represents the vehicle spacing, and k takes values ​​from 1 to 8, representing the eight flow directions at the intersection. Specifically, 1 represents straight ahead from the east; 2 represents a left turn from the east; 3 represents straight ahead from the south; 4 represents a left turn from the south; 5 represents straight ahead from the west; 6 represents a left turn from the west; 7 represents straight ahead from the north; and 8 represents a left turn from the north. See details... Figure 1 .

[0080] Simultaneously, left-turn guide lines 1-17, 2-18, 3-19, and 4-20 need to be installed at all four entrances to the intersection. This is to calculate the shortest green light time required for the left-turn phase of the intersection, which is determined by the length L of the left-turn guide line. b The width of the left-turn lanes at each entrance is R. b The angle between the entrance lane and the corresponding exit lane is θ b The decision is made using the following formula:

[0081]

[0082] The shortest green light time for straight-ahead traffic must meet the needs of pedestrians crossing the street, determined by the length L of the pedestrian crossing. a Pedestrian crossing speed v p The yellow light duration I is determined by the following formula:

[0083]

[0084] The maximum green light time should be the time required for all queuing vehicles within the detector's detection range to pass through the intersection, determined by the maximum detection length L of the RFID detector. m The calculation formula is determined as follows:

[0085]

[0086] Where int is the floor function.

[0087] II. Adjustment of release method and release time

[0088] Using equations (1) to (4), the green light time required to meet the traffic demand for each flow direction is obtained. It should be between the shortest green light time and the maximum green light time. The calculation formula is as follows:

[0089]

[0090] Next, the minimum green light time for both symmetrical and alternating unilateral release methods required to meet traffic demand is determined, specifically as follows:

[0091] 1) East-west direction

[0092] The formula for judgment is:

[0093] g 1_2 =max(g1, g2) (6)

[0094] g 5_6 =max(g5, g6) (7)

[0095] g 1_5 =max(g1, g5) (8)

[0096] g 2_6 =max(g2, g6) (9)

[0097] M E-W =sign(G EW2 -G EW1 )=sign[(g 1_5 +g 2_6 )-(g 1_2 +g 5_6 (10)

[0098] M E-WWhen M = 1, the east-west direction of the intersection adopts the "east single release-west single release" release mode; when M = -1 or 0, the east-west direction of the intersection adopts the "east-west straight-east-west left turn" release mode. E-W When M = 1, the east-west direction of the intersection adopts the "east single release-west single release" release mode; when M = -1 or 0, the east-west direction of the intersection adopts the "east-west straight-east-west left turn" release mode.

[0099] 2) South-north direction

[0100] The judgment formula is:

[0101] g 3_4 = max(g3, g4) (11)

[0102] g 7_8 = max(g7, g8) (12)

[0103] g 3_7 = max(g3, g7) (13)

[0104] g 4_8 = max(g4, g8) (14)

[0105] M S-N = sign(G SN2 -G SN1 ) = sign[(g 3_7 + g 4_8 )-(g 3_4 + g 7_8 )] (15)

[0106] M S-N When M = 1, the south-north direction of the intersection adopts the "south single release-north single release" release mode; when M = -1 or 0, the south-north direction of the intersection adopts the "south-north straight-south-north left turn" release mode. S-N When M = 1, the south-north direction of the intersection adopts the "south single release-north single release" release mode; when M = -1 or 0, the south-north direction of the intersection adopts the "south-north straight-south-north left turn" release mode.

[0107] The release mode of the east-west direction in the cycle is determined by equations (6)-(10), and the release mode of the south-north direction in the cycle is determined by equations (11)-(15).

[0108] Three, set up electronic display screen and bus special signal auxiliary light

[0109] In order to cooperate with the traffic signal light to prompt the driver when to drive away from the intersection, electronic display screen one 13, electronic display screen two 14, electronic display screen three 15, and electronic display screen four 16 are arranged facing the entrance at the four exit lanes. As shown in the figure, the specific control method of the electronic display screen is: Figure 4

[0110] 1) East-west direction

[0111] ​① Take "east-west straight - east-west left turn" release mode: intersection east-west straight phase, intersection east-west straight direction signal lamp display green light, east-west electronic display screen 13, 15 display "straight vehicle release", release time is g 1_5 , east-west straight green light time threshold after the implementation of east-west left turn phase, east-west straight direction signal lamp display red light, east-west left turn direction signal lamp display green light, east-west electronic display screen 13, 15 display "left turn vehicle release", release time is g 2_6 , east-west left turn green light time threshold, east-west left turn direction signal lamp display red light, east-west electronic display screen 13, 15 display "no pass".

[0112] ② Take "east-west straight - east-west left turn" release mode: intersection east-west straight phase, intersection east-west straight direction signal lamp display green light, east-west electronic display screen 13, 15 display "straight vehicle release", release time is g 1_2 , east-west straight green light time threshold after the implementation of east-west left turn phase, east-west straight direction signal lamp display red light, east-west left turn direction signal lamp display green light, east-west electronic display screen 13, 15 display "left turn vehicle release", release time is g 5_6 , east-west electronic display screen 15 display "no pass", west single release green light time threshold, west straight, left turn direction signal lamp display red light, east-west electronic display screen 13, 15 display "no pass".

[0113] 2) south-north direction

[0114] ① Take "south-north straight - south-north left turn" release mode: intersection south-north straight phase, intersection south-north straight direction signal lamp display green light, south-north electronic display screen 14, 16 display "straight vehicle release", release time is g 3_7 , south-north straight green light time threshold after the implementation of south-north left turn phase, south-north straight direction signal lamp display red light, south-north left turn direction signal lamp display green light, south-north electronic display screen 14, 16 display "left turn vehicle release", release time is g 4_8 , south-north left turn green light time threshold, south-north left turn direction signal lamp display red light, south-north electronic display screen 14, 16 display "no pass".

[0115] ② Take "south-north straight - south-north left turn" release mode: intersection south-north straight phase, intersection south-north straight direction signal lamp display green light, south-north electronic display screen 14, 16 display "straight vehicle release", release time is g 3_4, the south entrance straight, left turn direction signal lamp shows red light, the north entrance straight, left turn direction signal lamp shows green light, the south entrance electronic display screen 14 shows 14 "the north entrance all vehicles are allowed to release", the release time is g 7_8 , the south entrance electronic display screen 16 shows "prohibit traffic", after the single green light time threshold of the north entrance is reached, the straight, left turn direction signal lamp of the north entrance shows red light, the south and north entrance electronic display screen 14, 16 all show "prohibit traffic".

[0116] The present application is applicable to four-phase symmetric release crossroads provided with separate left turn lanes, and therefore is described by way of example.

[0117] As shown in Figure 4 , it is assumed that the included angle between the four-direction entrance lane and the corresponding exit lane of the crossroad is 90°, the road section speed limit is 60km / h, the detection distance of the RFID detector 9, 10, 11, 12 is 200m, the vehicle length is 5m, the vehicle spacing is 0.5m, the lane width is all 3.5m, the starting acceleration of the queued vehicle is 2m / s, the driver reaction time is all 0.5s, the starting delay is 1.5s, the length of the four entrance pedestrian crosswalks 22, 23, 24, 25 is all 24m, the length of the four left turn flow lines 17, 18, 19, 20 is all 30m, the pedestrian crossing speed is 1.2m / s, the yellow light time is 3s,

[0118] (1) calculate the shortest green light time and the maximum green light time of each flow direction

[0119] Taking the east entrance as an example, the straight shortest green light time and the maximum green light time are respectively:

[0120]

[0121]

[0122] The left turn shortest green light time and the maximum green light time are respectively:

[0123]

[0124]

[0125] Similarly, the shortest and maximum green light time of the straight and left turn vehicles of the west entrance, the south entrance and the north entrance are solved.

[0126] (2) east-west direction

[0127] Assuming that the number of vehicles queuing for straight traffic at the east exit is 15, the number of vehicles queuing for left turn at the east exit is 5, the number of vehicles queuing for straight traffic at the west exit is 20, and the number of vehicles queuing for left turn at the west exit is 10, the shortest green light time required to meet the traffic demand of all queuing vehicles is calculated according to formula (1), and the calculation result is rounded up.

[0128]

[0129]

[0130]

[0131]

[0132] According to formula (5) to formula (10), the green light time required for the "east-west straight- east-west left turn" release mode and the "east exit single release-west exit single release" release mode is respectively solved as follows: g 1_5 = 51s; g 2_6 = 28s; g 1_2 = 39s; g 5_6 = 51s, all meet the shortest green light time requirement and do not exceed the maximum green light time. Because:

[0133] g 1_2 +g 5_6 >g 1_5 +g 2_6

[0134] The green light time required for the "east exit single release-west exit single release" release mode is greater than the green light time required for the "east-west straight-east-west left turn" release mode, so the east-west direction adopts the "east-west straight (51s)-east-west left turn (28s)" release mode in this cycle.

[0135] (3) South-north direction

[0136] Assuming that the number of vehicles queuing for straight traffic at the south exit is 15, the number of vehicles queuing for left turn at the south exit is 10, the number of vehicles queuing for straight traffic at the north exit is 7, and the number of vehicles queuing for left turn at the north exit is 5, the shortest green light time required to meet the traffic demand of all queuing vehicles is calculated according to formula (1), and the calculation result is rounded up.

[0137]

[0138]

[0139]

[0140]

[0141] According to formula (5) and formula (11)-formula (15), the green light time required by the "south-north straight-left turn" release mode and the "south single release-north single release" release mode is respectively solved as follows: g 3_7 = 39s; g 4_8 = 28s; g 3_4 = 39s; g 7_8 = 20s, all meet the shortest green light time requirement and do not exceed the maximum green light time. Since:

[0142] g 3_4 +g 7_8 <g 3_7 +g 4_8

[0143] The green light time required by the "south single release-north single release" release mode is less than the green light time required by the "south-north straight-left turn" release mode, so the "south single release (39s)-north single release (20s)" release mode is adopted in the east-west direction in the cycle.

[0144] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0145] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A signal control method based on queue length difference detection, characterized by, It comprises the following steps: S1, RFID detector one (9), RFID detector two (10), RFID detector three (11), RFID detector four (12) are arranged at the entrance of the intersection to detect the number of queuing vehicles in each flow direction respectively; S2, the number of queuing vehicles in the east-west entrance straight and left turn of the intersection is detected, and the time required for all queuing vehicles in each flow direction to pass through the intersection is calculated; S3, the shortest green time G required for taking the east-west straight-left turn release mode EW1 , the green time G required for the east-only release-west-only release release mode EW2 ; S4, compare G EW1 and G EW2 , if G EW1 ≤ G EW1 , perform S5, else perform S7; S5, east straight line allows release, release time for g 1_5 , then into 3s yellow light time, turn S6; S6, straight prohibition release, left turn east and west allow release, release time for g 2_6 After entering the 3s yellow light time, turn S9; S7, straight ahead and left turn are allowed to release, the release time is g 1_2 After that, enter 3s yellow light time, turn S8; S8, east mouth forbidden to release, west mouth straight, left turn allowed to release, release time for g 5_6 , then enter 3s yellow light time, turn S9; S9, the number of queuing vehicles in the north-south entrance straight and left turn of the intersection is detected, and the time required for all queuing vehicles in each flow direction to pass through the intersection is calculated; S10, calculate the shortest green light time G required for taking the north-south straight - north-south left turn release mode SN1 , the green light time G required for the east single release - west single release release mode SN2 ; S11, compare G SN1 and G SN2 , if G SN1 ≤ G SN2 , execute S12, otherwise execute S14; S12, straight north-south, release time g 3_7 After 3s yellow light, turn S13; S13, straight prohibition of release, left turn of release, release time for g 4_8 After entering the 3s yellow light time, turn S2; S14, straight ahead and left turn allowed, release time is g 1_2 After 3s yellow light time, turn S15; S15, south mouth forbids to release, north mouth straight ahead, left turn allows to release, release time is g 5_6 After entering 3s yellow light time, turn S2.

2. The method of claim 1, wherein, In S2, the number of vehicles queuing in each approach lane j is detected k , the time required for all vehicles in each approach lane to pass through the intersection is calculated according to the driver reaction time τ, the vehicle start delay T c , the vehicle start acceleration a c , the vehicle length l, and the vehicle spacing d, which is specifically as follows: wherein, is j k the time required for all the vehicles in the queue to dissipate; j is the number of vehicles in the queue; i is the queue vehicle index; l i is the length of the ith vehicle; in the formula k takes 1-8, respectively representing 8 flow directions of the intersection, wherein 1 represents east straight; 2 represents east left turn; 3 represents south straight; 4 represents south left turn; 5 represents west straight; 6 represents west left turn; 7 represents north straight; and 8 represents north left turn.

3. The method of claim 1, wherein, In S3-S15, the release mode and release time determination formula is: 1) East-west direction M E-W = sign(G EW2 -G EW1 ) = sign[(g 1_5 + g 2_6 ) - (g 1_2 + g 5_6 )] wherein M E-W is a function of judging the east-west release mode, sign(·) is a sign function, M E-W = 1, the intersection east-west adopts the "east single release-west single release" release mode, and the release times are g 1_2 , g 5_6 ; M E-W = -1 or 0, the intersection east-west adopts the "east-west straight-east-west left turn" release mode, and the release times are g 1_5 , g 2_6 ; 2) North-south direction M S-N =sign(G SN2 -G SN1 )=sign[(g 3_7 +g 4_8 )-(g 3_4 +g 7_8 )] Wherein, M S-N is the judgment function of the north-south direction release mode, M S-N = 1, the intersection north-south direction adopts the "south single release - north single release" release mode, and the release time is g 3_4 , g 7_8 ; M S-N = -1 or 0, the intersection north-south direction adopts the "north-south straight - north-south left turn" release mode, and the release time is g 3_7 , g 4_8 .

4. The method of claim 3, wherein, Including the restriction: the release time of all flows should not be longer than the maximum green time set for the flow at the intersection When the phase time of any phase arrives , the next phase is switched automatically; the release time of all phases should not be shorter than the minimum green time set for the intersection When the calculation shows that the queued vehicles can be cleared before , the green time should be extended to and the next phase is switched, specifically: where g k is the k flow-to-green time; The calculation formula of the minimum and maximum green light time in each flow direction is: In the formula: is the minimum green time of each straight flow direction; is the minimum green time of each left-turn flow direction; R b is the width of each left-turn lane of the entrance; L a represents the length of the pedestrian crossing of the entrance; L m represents the maximum detection length of the RFID detector; v p represents the pedestrian crossing speed; I represents the set yellow light time; L b represents the length of the left-turn flow guide line of the direction; V m represents the road section speed limit; int(·) is a down rounding function; θ b represents the included angle between the entrance lane of the flow direction and the corresponding exit lane; in detail: θ2 represents the included angle between the east entrance left-turn lane and the south exit most inside exit lane; θ4 represents the included angle between the south entrance left-turn lane and the west exit most inside exit lane; θ6 represents the included angle between the west entrance left-turn lane and the north exit most inside exit lane; θ8 represents the included angle between the north entrance left-turn lane and the east exit most inside exit lane.

5. The method of claim 1, wherein, It also includes LED electronic display screen one (13), LED electronic display screen two (14), LED electronic display screen three (15), and LED electronic display screen four (16) arranged at the four exit lanes of the intersection, facing the entrance lanes, for operation prompt to the drivers; East-west direction: when the intersection executes "east-west straight—east-west left turn", the east-west LED electronic display screen one (13) and the LED electronic display screen three (15) display "straight vehicle allowed to pass" and "left turn vehicle allowed to pass" respectively; When the intersection executes "east single release—west single release", the LED electronic display screen three (15) displays "east all vehicles allowed to pass" during the east single release, and the LED electronic display screen one (13) displays "west all vehicles allowed to pass" during the west single release; North-south direction: when the intersection executes "north-south straight—north-south left turn", the north-south LED electronic display screen two (14) and the LED electronic display screen four (16) display "straight vehicle allowed to pass" and "left turn vehicle allowed to pass" respectively; When the intersection executes "south single release—north single release", the LED electronic display screen two (14) displays "north all vehicles allowed to pass" during the north single release, and the LED electronic display screen four (16) displays "south all vehicles allowed to pass" during the south single release, and the rest of the time, each display screen displays "prohibited to pass".

6. A control system according to the method of any one of claims 1-5, characterized by It comprises RFID detectors, a central signal system, a traffic signal control machine, and electronic display screens; the central signal system is connected with the RFID detectors and the traffic signal control machine respectively, and the output of the traffic signal control machine is connected with the electronic display screens and the intersection signal lights respectively; The RFID detectors detect the number of queuing vehicles at the entrance lanes of the intersection in each flow direction in real time, and send the detection data to the central signal system; The central signal system analyzes the collected queuing vehicle data to obtain the detection results, and sends them to the traffic signal control machine; The traffic signal control machine adjusts the release mode and release time of the intersection according to the analysis results of the central signal system, and sends the timing scheme execution results to the central signal system; The electronic display screens are used to prompt the drivers in each flow direction when they are allowed to pass through the intersection, and the intersection signal lights are used to output the corresponding light colors.

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