Intersection lane division and signal timing cooperative control method in automatic driving environment

Abstract

The invention relates to an intersection lane division and signal timing cooperative control method in an automatic driving environment, and belongs to the field of intelligent traffic. According to the method, lane function division schemes in corresponding directions are published by using lane function adjustment marks, signal timing schemes in corresponding directions are published by using lane-level signal lamps, and personalized suggestion schemes are pushed to network-connected automatic driving vehicles by using a network-connected communication technology, so that lane-level and vehicle-level refined intelligent management and control are realized, and the intelligent management and control efficiency is improved. The intersection traffic efficiency is improved, and intersection road traffic resources are utilized to the maximum extent. According to the invention, the problem of insufficient management refinement of the plane intersection can be overcome, the traffic capacity of the intersection is improved, traffic congestion is reduced, and the utilization rate of road traffic resources is improved.

Description

Technical Field

[0001] The present invention belongs to the field of intelligent transportation and relates to a method for coordinated control of intersection lane division and signal timing in an automatic driving environment. Background Art

[0002] With the continuous development of connected autonomous driving technology, intersections will gradually see multiple streams of vehicles, including human-driven vehicles (HDVs) and autonomous vehicles (CAVs), mixed with left-turning, straight-going, and right-turning vehicles, and the complexity of traffic management will increase dramatically. In particular, the mutual interference between vehicles in different directions can easily lead to traffic disruption, traffic congestion, and affect the efficiency of intersection traffic.

[0003] Therefore, there is an urgent need for an intersection traffic control method in an autonomous driving environment to overcome the problem of insufficient refinement in existing planar intersection management. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a method for coordinated control of intersection lane division and signal timing in an autonomous driving environment, so as to overcome the problem of insufficient refinement in existing planar intersection management, improve intersection capacity, reduce traffic congestion, and improve the utilization rate of road traffic resources.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for coordinated control of lane division and signal timing at an intersection in an autonomous driving environment. Lane function adjustment signs are used to publish lane function division plans for corresponding directions, lane-level signal lights are used to publish signal timing plans for corresponding directions, and networked communication technology is used to push personalized suggestions to networked autonomous driving vehicles, thereby achieving lane-level and vehicle-level refined intelligent control, improving intersection traffic efficiency, and maximizing the use of intersection road traffic resources.

[0007] The method specifically comprises the following steps:

[0008] S1: Establish a coordinated control system for intersection lane division and signal timing under an autonomous driving environment, and set 2 to 4 groups of lane function adjustment signs and 1 to 2 groups of lane-level signal lights with networking functions in each direction of the intersection; the lane function adjustment signs include lane-level variable information signs and variable guide lane signs, which are used to dynamically switch the types of lanes in the lane function adjustment area; each group of lane function adjustment signs and signal lights are connected by communication technology for networking control, and can interact with the networked autonomous driving vehicles in real time;

[0009] S2: Based on the real-time detection of traffic demands of different directions at the intersection (including left-turning autonomous vehicles, straight-going autonomous vehicles, right-turning autonomous vehicles, left-turning manually-driven vehicles, straight-going manually-driven vehicles, and right-turning manually-driven vehicles), the proposed lane function division scheme and signal timing scheme are determined through the intersection centralized decision-making unit;

[0010] S3: Each group of lane function adjustment signs publishes the lane function division plan for the corresponding direction, the lane-level traffic lights publish the signal timing plan for the corresponding direction, and use the networked communication technology to push personalized suggestions to the networked autonomous driving vehicles.

[0011] Further, in step S2, the lane function division scheme specifically includes lanes allowing vehicles to travel and lanes turning;

[0012] The lanes allow the following vehicles to travel: dedicated lanes for autonomous driving, dedicated lanes for manual driving, and general lanes. Dedicated lanes for autonomous driving are only allowed to be used by autonomous driving vehicles; dedicated lanes for manual driving are only allowed to be used by manually driven vehicles; general lanes allow both autonomous driving vehicles and manually driven vehicles to be used, and the two types of vehicles will queue up in the order in which they arrive. Since the queueing order of vehicles is not fixed, all vehicles in the lane are required to be released at the same phase;

[0013] Lane turning: single turning lane, lane shared by two or more traffic flows, lane reused by two or more traffic flows, and left-turn borrowing lane; single turning lane includes left-turn lane, straight lane and right-turn lane, and is only for the corresponding traffic flow; lane shared by two or more traffic flows includes straight-left shared lane, straight-right shared lane, left-right shared lane and straight-left-right shared lane. For example, the straight-left shared lane allows straight and left-turn traffic to use it at the same time, and the vehicles of the two traffic flows queue up in the order of arrival. Since the queueing order of vehicles is not certain, all vehicles in the lane are required to be released in the same phase; lanes reused by two or more traffic flows include straight-left reuse lane, straight-right reuse lane, left-right reuse lane and straight-left-right reuse lane, which are only applicable to autonomous driving vehicles and need to be used with Dedicated lanes for autonomous driving are used in conjunction with each other. For example, the straight-left multiplexed lane allows two streams of traffic, straight and left-turning, to use it at the same time, but requires the two streams of traffic to adjust the vehicle order through a trajectory optimization algorithm on the upstream section to ensure that all left-turning vehicles are ahead of straight-moving vehicles or all straight-moving vehicles are ahead of left-turning vehicles within a cycle. In this way, in the current cycle, they can be separated by time and space, and left-turning vehicles can be released in the left-turn phase, and straight-moving vehicles can be released in the straight-moving phase. The two streams of traffic do not need to be released in the same phase; the left-turn borrowing lane is only applicable to left-turning autonomous driving vehicles and needs to be used in conjunction with the dedicated autonomous driving lane. When the exit lane is not used by the exit vehicle, it can be dynamically borrowed to the left-turning autonomous driving vehicle for use. The left-turning autonomous driving vehicle enters the exit lane from the opening of the median divider.

[0014] Further, in step S2, the signal phase of the signal timing scheme includes a conventional signal phase and a phase dedicated to autonomous driving; the conventional signal phase allows both autonomous driving vehicles and manually driven vehicles to pass; and the phase dedicated to autonomous driving allows only autonomous driving vehicles to pass.

[0015] Further, in step S2, the optimization decision method of the intersection centralized decision unit is to minimize the average vehicle delay;

[0016] The objective function is:

[0017]

[0018] Where j represents the direction, j∈J={1,2,3,4} are west, south, east and north respectively; k represents the lane number, k∈K j ={1,2,…,n j -1,n j}; K j =K j,1 ∪K j,2 , K j,1 ={n j,2 +1,…,n j -1,n j} represents the lane number on the import side, K j,2 ={1,2,…,n j,2 -1,n j,2} indicates the lane number on the exit side; n j Indicates the total number of lanes in direction j, n j,1 、n j,2 Respectively indicate direction j Number of import and export lanes, n j =n j,1 +n j,2 ;d k means that all vehicles traveling in lane k are delayed; q k represents the total traffic flow on lane k;

[0019] (1) Lane division

[0020] Each import lane must and can only be set as one type of lane; each traffic flow has at least one import lane for it to travel; to avoid different traffic flows crossing on different lanes, there shall be at most one straight left and right shared lane and one straight left shared lane, and at most one straight right shared lane and one straight left and right shared lane; if there are straight left and right shared lanes, a straight lane cannot be set at the same time; the left turn lane shall be set to the left side of the straight lane, the straight left shared lane, the straight right shared lane and the straight left and right shared lane, and the straight lane, the straight left shared lane, the straight right shared lane and the straight left and right shared lane shall be set to the left side of the right turn lane, and the above lanes shall not be set on the exit side; the number of import lanes for left turn, straight and right turn shall not be greater than the number of corresponding exit lanes; each lane can be set to this type of lane only if supported by the traffic police, traffic regulations and field equipment;

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038] Wherein, h represents the lane type, and h∈H={1,2,…,17,18} are respectively the autonomous driving dedicated lane-left turn lane, the manual driving dedicated lane-left turn lane, the general lane-left turn lane, the autonomous driving dedicated lane-straight lane, the manual driving dedicated lane-straight lane, the general lane-straight lane, the autonomous driving dedicated lane-right turn lane, the manual driving dedicated lane-right turn lane, the general lane-right turn lane, the autonomous driving dedicated lane-straight left shared lane, the manual driving dedicated lane-straight left shared lane, the general lane-straight left shared lane, the autonomous driving dedicated lane-straight right shared lane, the manual driving dedicated lane-straight right shared lane, the general lane-straight right shared lane, the autonomous driving dedicated lane-straight left and right shared lane, the manual driving dedicated lane-straight left and right shared lane, and the general lane-straight left and right shared lane; x k,h Indicates whether lane k is of lane type h, x k,h ∈{0,1} are respectively no and yes; X k,h Indicates whether the traffic police or external equipment supports setting lane k to lane type h, X k,h ∈{0,1} are no and yes respectively;

[0039] (2) Phase Constraint

[0040] There are 16 intersecting points, 4 diverging points and 4 merging points for left turns and straight-ahead traffic at intersections. Generally, two traffic flows with merging conflicts are not released at the same time. If two traffic flows diverge without conflicts, the conflict matrix for left turns and straight-ahead traffic includes a conflict matrix composed of 16 intersecting points and 4 merging points. Constraints are set according to the conflict matrix to automatically generate feasible phase sequence schemes in the optimization model. The phase for releasing the autonomous driving traffic flow is required to be consistent with the phase for releasing the manually driven traffic flow.

[0041]

[0042]

[0043]

[0044]

[0045]

[0046] Where f represents the conflict matrix, f i,i′ Indicates whether there is a conflict between flow direction i and flow direction i′ at the intersection, f i,i′ ∈{0,1} are respectively no and yes; U represents a maximum constant; y i,i′ Indicates whether the green light on time for flow direction i is earlier than that for flow direction i′, y i,i′ ∈{0,1} are respectively no and yes; t iIndicates the time when the green light turns on in direction i; g i Indicates the duration of the green light in direction i; r i It indicates the green light interval time of adjacent phases in flow direction i, that is, the yellow light time;

[0047] There are minimum and maximum constraints on the cycle duration; the green light start and end time should be within the phase release cycle range; there is a minimum constraint on the green light duration; the shortest green light duration for pedestrians to cross the street must be guaranteed; if there is a straight left and right shared lane or a straight left shared lane, the left turn and straight release periods should overlap; if there is a straight left and right shared lane or a straight right shared lane, the right turn release period should include the straight release period; right-turn traffic uses the red light right turn method;

[0048] C min ≤C≤C max

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] Among them, C represents the cycle length, C min , C max Respectively represent the minimum and maximum cycle duration; g min Indicates the minimum green light duration; L j,p represents the length of the crosswalk in direction j; v p Indicates pedestrian walking speed;

[0059] The green light duration for each lane should be within a reasonable range; the green light duration for the right-turn lane is equal to the right-turn green light duration; the green light duration for the straight-right shared lane, straight-left shared lane, straight lane, and straight-left shared lane is equal to the straight-through green light duration; the left-turn lane is equal to the left-turn green light duration;

[0060]

[0061] Among them, gk Indicates the duration of the green light for lane k;

[0062] (3) Traffic distribution

[0063] The flow rate of a lane is greater than 0 only if a certain flow direction is allowed to travel, otherwise it is equal to 0; the sum of the flow rates of all lanes selected by each flow direction is equal to the total flow rate; the total flow rate of each lane is equal to the sum of the flow rates of the lane selected by each flow direction;

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072] Among them, q i,k represents the flow rate of direction i choosing lane k; q i represents the traffic demand of direction i; i∈I={1,2,…,23,24} respectively means west left turn CAV, west straight CAV, west right turn CAV, west left turn HDV, west straight HDV, west right turn HDV, south left turn CAV, south straight CAV, south right turn CAV, south left turn HDV, south straight HDV, south right turn HDV, east left turn CAV, east straight CAV, east right turn CAV, east left turn HDV, east straight HDV, east right turn HDV, north left turn CAV, north straight CAV, north right turn CAV, north left turn HDV, north straight HDV, north right turn HDV; i∈I j ={6j-5,6j-4,6j-3,6j-2,6j-1,6j} are the flow directions in direction j;

[0073] (4) Delay calculation

[0074] The calculation formula for the average delay of vehicles on each lane adopts the classic HCM2010 formula, as follows:

[0075]

[0076]

[0077]

[0078]

[0079] Among them, λ k represents the green signal ratio of lane k; k represents the lane k saturation; e represents the intersection signal control type calibration coefficient; represents the capacity of lane k; T represents the duration of the analysis period; s h represents the saturation flow rate of lane type h;

[0080] (5) Specific constraint requirements

[0081] If shared lanes are not allowed, add the following constraints:

[0082]

[0083] You can choose to specify the time when the green light turns on in the specified direction as the start time of the cycle. For example, choose the time when the green light turns on for the west left as time 0, as follows

[0084]

[0085] In order to avoid excessive pursuit of the minimum average delay of the intersection, coupled with the random arrival of vehicles, which may lead to oversaturation of a certain flow direction, the following constraints are added: Generally, μ max =0.85, the intersection is in an unsaturated state; if adding this constraint results in no feasible solution for the optimization model, let μ max =1, the intersection is in a highly saturated state; if there is still no feasible solution, this constraint is deleted, indicating that the intersection is in an oversaturated state;

[0086]

[0087] Among them, μ max Indicates the upper limit of saturation.

[0088] Further, in step S2, the control requirement of the decision-making unit is:

[0089] Lane division variable (x k,h ) belongs to the dynamic lane function control strategy, that is, the variable guide lane, which generally changes once every 1 hour or more, and the lane clearance during the function change transition process must be considered; if the variable is consistent with the previous cycle, it is taken as the constant value of the previous cycle and substituted into the optimization model;

[0090] Phase sequence variable (y i,i′) is the phase sequence adjustment of the adaptive signal control strategy, which generally changes every 30 minutes or more; if the variable is consistent with the previous cycle, it is taken as the constant value of the previous cycle and substituted into the optimization model;

[0091] Signal timing variable (t i , g i , g k , C) The green light duration adjustment belongs to the adaptive signal control strategy, which generally changes once a signal cycle.

[0092] The beneficial effects of the present invention are that the present invention can be applied to flat intersections, by using lane function adjustment signs to publish lane function division plans for corresponding directions, lane-level signal lights to publish signal timing plans for corresponding directions, and using networked communication technology to push personalized suggestions to networked autonomous driving vehicles, thereby achieving lane-level and vehicle-level refined intelligent control, improving road traffic efficiency, and ensuring efficient, safe, and smooth traffic operation.

[0093] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0095] Figure 1 A system diagram of the intersection lane division and signal timing coordination method in the autonomous driving environment of the present invention;

[0096] Figure 2 This is a flow chart of the method for coordinated intersection lane division and signal timing in an autonomous driving environment of the present invention;

[0097] Figure 3 Schematic diagram of lane operation rules of the method of the present invention;

[0098] Figure 4 A schematic diagram of a lane function division scheme information release pattern for the method of the present invention. DETAILED DESCRIPTION

[0099] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0100] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0101] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0102] See also Figure 1 to Figure 4 The present invention provides a method for coordinated control of intersection lane division and signal timing in an autonomous driving environment, which specifically includes the following steps:

[0103] Step 1: Establish a coordinated control system for intersection lane division and signal timing in an autonomous driving environment, and set up 2 to 4 lane function adjustment signs and 1 to 2 lane-level signal lights with networking functions in each direction of the intersection. The lane function adjustment signs include lane-level variable information signs and variable guide lane signs, which are used to dynamically switch the types of lanes in the lane function adjustment area. Each set of lane function adjustment signs and signal lights are connected by communication technology for networking control, and can interact with the networked autonomous driving vehicles in real time.

[0104] Step 2: Based on the real-time detection of traffic demands in different directions at the intersection (including left-turning autonomous vehicles, straight-going autonomous vehicles, right-turning autonomous vehicles, left-turning manually-driven vehicles, straight-going manually-driven vehicles, and right-turning manually-driven vehicles), the proposed lane function division plan and signal timing plan are determined through the intersection centralized decision-making unit.

[0105] Step 3: Each group of lane function adjustment signs publishes the lane function division plan for the corresponding direction, and the lane-level traffic lights publish the signal timing plan for the corresponding direction. The networked communication technology is used to push personalized suggestions to the networked autonomous driving vehicles.

[0106] In step 2, the lane function division scheme specifically includes: lanes allowing vehicles to travel and lanes turning.

[0107] The following vehicles are allowed to drive in the lanes: dedicated lanes for autonomous driving, dedicated lanes for manual driving, and general lanes. Dedicated lanes for autonomous driving are only allowed to be used by autonomous driving vehicles. Dedicated lanes for manual driving are only allowed to be used by manually driven vehicles. General lanes are allowed to be used by both autonomous driving vehicles and manually driven vehicles. The two types of vehicles will queue up in the order in which they arrive. Since the order in which the vehicles queue up is not fixed, all vehicles in the lane are required to be released at the same phase.

[0108] Lane turning: single turning lane, lane shared by two or more traffic flows, lane reused by two or more traffic flows, left-turn borrowing lane. Single turning lanes include left-turn lanes, straight lanes, and right-turn lanes, which are only for the corresponding traffic flow. Lanes shared by two or more traffic flows include straight-left shared lanes, straight-right shared lanes, left-right shared lanes, and straight-left-right shared lanes. For example, a straight-left shared lane allows straight and left-turning traffic flows to use it at the same time, and the vehicles of the two traffic flows queue up in the order of arrival. Since the queueing order of vehicles is not fixed, all vehicles in the lane are required to be released at the same phase. Lanes for multiplexing of two or more traffic flows, including straight-left multiplexing lanes, straight-right multiplexing lanes, left-right multiplexing lanes, and straight-left-right multiplexing lanes, are only applicable to autonomous vehicles and must be used in conjunction with dedicated autonomous driving lanes. For example, a straight-left multiplexing lane allows two traffic flows, straight and left-turning, to be used simultaneously, but requires the two traffic flows to adjust the vehicle order through a trajectory optimization algorithm in the upstream section to ensure that all left-turning vehicles are ahead of straight-moving vehicles or all straight-moving vehicles are ahead of left-turning vehicles in a cycle. In this way, in the current cycle, they can be separated by time and space, and left-turning vehicles can be released in the left-turn phase, and straight-moving vehicles can be released in the straight-moving phase. The two traffic flows do not need to be released in the same phase. Left-turn borrowing lanes are only applicable to left-turning autonomous vehicles and must be used in conjunction with dedicated autonomous driving lanes. When the exit lane is not used by exit vehicles, it can be dynamically borrowed for use by left-turning autonomous vehicles, and left-turning autonomous vehicles enter the exit lane from the opening of the median divider.

[0109] The lane function division plan and information release are shown in Table 1.

[0110] Table 1 Lane function division plan and information release content

[0111]

[0112]

[0113] The signal phases of the signal timing plan include regular signal phases and phases dedicated to autonomous driving. Regular signal phases allow both autonomous driving vehicles and manually driven vehicles to pass. The phase dedicated to autonomous driving allows only autonomous driving vehicles to pass.

[0114] Optimize the decision-making method as follows:

[0115] 1) Parameter explanation, as shown in Table 2.

[0116] Table 2 Parameter explanation

[0117]

[0118]

[0119] 2) Objective function: Minimize average vehicle delay

[0120]

[0121] 3) Constraints:

[0122] (1) Lane division

[0123] Each import lane must and can only be set to one type of lane. Each traffic flow has at least one import lane for it to travel. To avoid different traffic flows crossing on different lanes, there shall be at most one straight left and right shared lane and one straight left shared lane, and at most one straight right shared lane and one straight left and right shared lane. If there are straight left and right shared lanes, straight lanes cannot be set at the same time. The left turn lane must be set to the left side of the straight lane, straight left shared lane, straight right shared lane, and straight left and right shared lanes, and the straight lane, straight left shared lane, straight right shared lane, and straight left and right shared lanes must be set to the left side of the right turn lane. At the same time, the above lanes cannot be set on the exit side. The number of import lanes for left turn, straight driving, and right turn shall not be greater than the number of corresponding exit lanes. Each lane can only be set to this type of lane if it is supported by the traffic police, traffic regulations, and field equipment.

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141] (2) Phase Constraint

[0142] There are 16 intersecting points, 4 diverging points, and 4 merging points for left turns and straight-ahead traffic at intersections. Generally, two traffic flows with merging conflicts are not released at the same time. If there is no conflict when two traffic flows diverge, the conflict matrix for left turns and straight-ahead traffic includes a conflict matrix composed of 16 intersecting points and 4 merging points. Constraints are set according to the conflict matrix to automatically generate feasible phase sequence schemes in the optimization model. The phase for releasing the autonomous driving traffic flow is required to be consistent with the phase for releasing the manually driven traffic flow.

[0143]

[0144]

[0145]

[0146]

[0147]

[0148] The cycle duration has minimum and maximum constraints. The green light start and end time should be within the phase release cycle. The green light duration has a minimum constraint. It is necessary to ensure the shortest green light duration for pedestrians to cross the street. If there is a straight left and right shared lane or a straight left shared lane, the left turn and straight release periods should overlap. If there is a straight left and right shared lane or a straight right shared lane, the right turn release period should include the straight release period. Right-turn traffic uses the red light right turn method.

[0149] C min ≤C≤C max

[0150]

[0151]

[0152]

[0153]

[0154]

[0155]

[0156]

[0157]

[0158]

[0159]

[0160] The green light duration for each lane should be within a reasonable range. The green light duration for the right-turn lane is equal to the right-turn green light duration. The green light duration for the straight-right shared lane, straight-left shared lane, straight lane, and straight-left shared lane is equal to the straight green light duration.

[0161] The left turn lane is equal to the length of the left turn green light.

[0162]

[0163] (3) Traffic distribution

[0164] The flow rate of a lane is greater than 0 only when a certain flow direction is allowed to travel, otherwise it is equal to 0. The sum of the flow rates of all lanes selected by each flow direction is equal to the total flow rate. The total flow rate of each lane is equal to the sum of the flow rates of each flow direction selected in that lane.

[0165]

[0166]

[0167]

[0168]

[0169]

[0170]

[0171]

[0172]

[0173] (4) Delay calculation

[0174] The calculation formula for the average delay of vehicles on each lane adopts the classic HCM2010 formula, as follows

[0175]

[0176]

[0177]

[0178]

[0179] (5) Specific constraint requirements

[0180] If shared lanes are not allowed, add the following constraints

[0181]

[0182] You can choose to specify the time when the green light turns on in the specified direction as the start time of the cycle. For example, choose the time when the green light turns on for the west left as time 0, as follows

[0183]

[0184] In order to avoid excessive pursuit of the minimum average delay of the intersection, coupled with the random arrival of vehicles, which may lead to oversaturation of a certain flow direction, the following constraints are added. Generally, μ max = 0.85, the intersection is in an unsaturated state. If adding this constraint results in no feasible solution for the optimization model, let μ max =1, the intersection is in a highly saturated state. If there is still no feasible solution, delete this constraint, indicating that the intersection is in an oversaturated state.

[0185]

[0186] The control requirements for the decision-making method are as follows:

[0187] Lane division variable (x k,h) belongs to the dynamic lane function control strategy, that is, the variable guide lane, which generally changes once every 1 hour or more, and the lane clearance during the function change transition process must be considered. If the variable is consistent with the previous cycle, it is taken as the constant value of the previous cycle and substituted into the optimization model.

[0188] Phase sequence variable (y i,i′ ) is a phase sequence adjustment of the adaptive signal control strategy, which generally changes every 30 minutes. If the variable is consistent with the previous cycle, it is taken as the constant value of the previous cycle and substituted into the optimization model.

[0189] Signal timing variable (t i , g i , g k , C) The green light duration adjustment belongs to the adaptive signal control strategy, which generally changes once a signal cycle.

[0190] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for coordinated control of intersection lane division and signal timing in an autonomous driving environment, characterized in that: The method specifically comprises the following steps: S1: Establish a coordinated control system for intersection lane division and signal timing in an autonomous driving environment, and set 2 to 4 groups of lane function adjustment signs and 1 to 2 groups of lane-level signal lights with networking functions in each direction of the intersection; the lane function adjustment signs include lane-level variable information signs and variable guide lane signs, which are used to dynamically switch the types of lanes in the lane function adjustment area; each group of lane function adjustment signs and signal lights are connected by communication technology for networking control, and exchange information with the networked autonomous driving vehicles in real time; S2: Based on the real-time detection of traffic demand in different directions at the intersection, the proposed lane function division scheme and signal timing scheme are determined through the intersection centralized decision-making unit; S3: Each group of lane function adjustment signs publishes the lane function division plan for the corresponding direction, the lane-level traffic lights publish the signal timing plan for the corresponding direction, and use the networked communication technology to push personalized suggestions to the networked autonomous driving vehicles.

2. The method for coordinated control of intersection lane division and signal timing in an autonomous driving environment according to claim 1, characterized in that: In step S2, the different flow directions include left-turning automatic driving vehicles, straight-moving automatic driving vehicles, right-turning automatic driving vehicles, left-turning manually driven vehicles, straight-moving manually driven vehicles, and right-turning manually driven vehicles; The lane function division scheme specifically includes lanes allowing vehicles to travel and lanes turning; The lanes allow vehicles to travel: dedicated lanes for autonomous driving, dedicated lanes for manual driving, and general lanes; The dedicated autonomous driving lane is only for autonomous driving vehicles. Manual driving dedicated lanes are only for use by manually driven vehicles; general lanes are for use by both automated and manually driven vehicles. The two types of vehicles will queue up in the order in which they arrive. Since the queueing order of vehicles is not fixed, all vehicles in the lane are required to be released at the same phase. Lane turning: single turning lane, lane shared by two or more traffic flows, lane reused by two or more traffic flows, and left-turn borrowing lane; single turning lane includes left-turn lane, straight lane and right-turn lane, and is only for the corresponding traffic flow; lane shared by two or more traffic flows includes straight-left shared lane, straight-right shared lane, left-right shared lane and straight-left-right shared lane. For example, the straight-left shared lane allows straight and left-turn traffic to use it at the same time, and the vehicles of the two traffic flows queue up in the order of arrival. Since the queueing order of vehicles is not certain, all vehicles in the lane are required to be released in the same phase; lanes reused by two or more traffic flows include straight-left reuse lane, straight-right reuse lane, left-right reuse lane and straight-left-right reuse lane, which are only applicable to autonomous driving vehicles and need to be used with Dedicated autonomous driving lanes are used in conjunction with each other. For example, the straight-left multiplexed lane allows straight and left-turning traffic to be used at the same time, but the two traffic flows are required to adjust the vehicle order through the trajectory optimization algorithm in the upstream section to ensure that all left-turning vehicles are ahead of straight vehicles or all straight vehicles are ahead of left-turning vehicles within a cycle. In this way, in the current cycle, they can be separated by time and space, and left-turning vehicles can be released in the left-turn phase, and straight vehicles can be released in the straight phase. The two traffic flows do not need to be released in the same phase; the left-turn borrowing lane is only applicable to left-turning autonomous driving vehicles and needs to be used in conjunction with the dedicated autonomous driving lane. When the exit lane is not used by the exit vehicle, it can be dynamically borrowed to the left-turning autonomous driving vehicle for use. The left-turning autonomous driving vehicle enters the exit lane from the opening of the median divider.

3. The method for coordinated control of intersection lane division and signal timing in an autonomous driving environment according to claim 1, characterized in that: In step S2, the signal phase of the signal timing scheme includes a regular signal phase and a phase dedicated to autonomous driving; the regular signal phase allows both autonomous driving vehicles and manually driven vehicles to pass; the phase dedicated to autonomous driving allows only autonomous driving vehicles to pass.

4. The method for coordinated control of intersection lane division and signal timing in an autonomous driving environment according to claim 2, characterized in that: In step S2, the optimization decision method of the intersection centralized decision unit is to minimize the average vehicle delay; The objective function is: Where j represents the direction, j∈J={1,2,3,4} are west, south, east and north respectively; k represents the lane number, k∈K j ={1,2,…,n j -1,n j }; K j =K j,1 ∪K j,2 , K j,1 ={n j,2 +1,…,n j -1,n j } represents the lane number on the import side, K j,2 ={1,2,…,n j,2 -1,n j,2 } indicates the lane number on the exit side; n j Indicates the total number of lanes in direction j, n j,1 、n j,2 Respectively represent the number of lanes for the entrance and exit of direction j, n j =n j,1 +n j,2 ;d k means that all vehicles traveling in lane k are delayed; q k represents the total traffic flow on lane k; (1) Lane division Each import lane must and can only be set as one type of lane; each traffic flow has at least one import lane for it to travel; to avoid different traffic flows crossing on different lanes, there shall be at most one straight left and right shared lane and one straight left shared lane, and at most one straight right shared lane and one straight left and right shared lane; if there are straight left and right shared lanes, a straight lane cannot be set at the same time; the left turn lane shall be set to the left side of the straight lane, the straight left shared lane, the straight right shared lane and the straight left and right shared lane, and the straight lane, the straight left shared lane, the straight right shared lane and the straight left and right shared lane shall be set to the left side of the right turn lane, and the above lanes shall not be set on the exit side; the number of import lanes for left turn, straight and right turn shall not be greater than the number of corresponding exit lanes; each lane can be set to this type of lane only when supported by the traffic police, traffic regulations and field equipment; Wherein, h represents the lane type, and h∈H={1,2,…,17,18} are respectively the autonomous driving dedicated lane-left turn lane, the manual driving dedicated lane-left turn lane, the general lane-left turn lane, the autonomous driving dedicated lane-straight lane, the manual driving dedicated lane-straight lane, the general lane-straight lane, the autonomous driving dedicated lane-right turn lane, the manual driving dedicated lane-right turn lane, the general lane-right turn lane, the autonomous driving dedicated lane-straight left shared lane, the manual driving dedicated lane-straight left shared lane, the general lane-straight left shared lane, the autonomous driving dedicated lane-straight right shared lane, the manual driving dedicated lane-straight right shared lane, the general lane-straight right shared lane, the autonomous driving dedicated lane-straight left and right shared lane, the manual driving dedicated lane-straight left and right shared lane, and the general lane-straight left and right shared lane; x k,h Indicates whether lane k is of lane type h, x k,h ∈{0,1} are respectively no and yes; X k,h Indicates whether the traffic police or external equipment supports setting lane k to lane type h, X k,h ∈{0,1} are no and yes respectively; (2) Phase Constraint There are 16 intersecting points, 4 diverging points and 4 merging points for left turns and straight-ahead traffic at the intersection. Two traffic flows with merging conflicts should not be released at the same time. If the two traffic flows diverge without conflicts, the conflict matrix for left turns and straight-ahead traffic includes a conflict matrix composed of 16 intersecting points and 4 merging points. Constraints are set according to the conflict matrix to automatically generate feasible phase sequence schemes in the optimization model. The phase for releasing the autonomous driving traffic flow is required to be consistent with the phase for releasing the manually driven traffic flow. Where f represents the conflict matrix, f i,i′ Indicates whether there is a conflict between flow direction i and flow direction i′ at the intersection, f i,i′ ∈{0,1} are respectively no and yes; U represents a maximum constant; y i,i′ Indicates whether the green light on time for flow direction i is earlier than that for flow direction i′, y i,i′ ∈{0,1} are respectively no and yes; t i Indicates the time when the green light turns on in direction i; g i Indicates the duration of the green light in direction i; r i It indicates the green light interval time of adjacent phases in flow direction i, that is, the yellow light time; There are minimum and maximum constraints on the cycle duration; the green light start and end time should be within the phase release cycle range; there is a minimum constraint on the green light duration; the shortest green light duration for pedestrians to cross the street must be guaranteed; if there is a straight left and right shared lane or a straight left shared lane, the left turn and straight release periods should overlap; if there is a straight left and right shared lane or a straight right shared lane, the right turn release period should include the straight release period; right-turn traffic uses the red light right turn method; C min ≤C≤C max Among them, C represents the cycle length, C min , C max Respectively represent the minimum and maximum cycle duration; g min Indicates the minimum green light duration; L j,p represents the length of the crosswalk in direction j; v p Indicates pedestrian walking speed; The green light duration for each lane should be within a reasonable range; the green light duration for the right-turn lane is equal to the right-turn green light duration; the green light duration for the straight-right shared lane, straight-left shared lane, straight lane, and straight-left shared lane is equal to the straight-through green light duration; the left-turn lane is equal to the left-turn green light duration; Among them, g k Indicates the duration of the green light for lane k; (3) Traffic distribution The flow rate of a lane is greater than 0 only if a certain flow direction is allowed to travel, otherwise it is equal to 0; the sum of the flow rates of all lanes selected by each flow direction is equal to the total flow rate; the total flow rate of each lane is equal to the sum of the flow rates of the lane selected by each flow direction; Among them, q i,k represents the flow rate of direction i choosing lane k; q i represents the traffic demand of direction i; i∈I={1,2,…,23,24} respectively means west left turn CAV, west straight CAV, west right turn CAV, west left turn HDV, west straight HDV, west right turn HDV, south left turn CAV, south straight CAV, south right turn CAV, south left turn HDV, south straight HDV, south right turn HDV, east left turn CAV, east straight CAV, east right turn CAV, east left turn HDV, east straight HDV, east right turn HDV, north left turn CAV, north straight CAV, north right turn CAV, north left turn HDV, north straight HDV, north right turn HDV; i∈I j ={6j-5,6j-4,6j-3,6j-2,6j-1,6j} are the flow directions in direction j; (4) Delay calculation The formula for calculating the average delay of vehicles traveling on each lane is as follows: Among them, λ k represents the green signal ratio of lane k; k represents the lane k saturation; e represents the intersection signal control type calibration coefficient; represents the capacity of lane k; T represents the duration of the analysis period; s h represents the saturation flow rate of lane type h; (5) Specific constraint requirements If shared lanes are not allowed, add the following constraints: Select the time when the green light turns on in the specified direction as the start time of the cycle. For example, select the time when the green light turns on for the west left as time 0, as follows In order to avoid excessive pursuit of the minimum average delay of the intersection, coupled with the random arrival of vehicles, which may lead to oversaturation of a certain flow direction, the following constraints are added: Take μ max =0.85, the intersection is in an unsaturated state; if adding this constraint results in no feasible solution for the optimization model, let μ max =1, the intersection is in a highly saturated state; if there is still no feasible solution, this constraint is deleted, indicating that the intersection is in an oversaturated state; Among them, μ max Indicates the upper limit of saturation.

5. The method for coordinated control of intersection lane division and signal timing in an autonomous driving environment according to claim 4 is characterized in that: In step S2, the control requirements of the decision-making unit are: Lane division variable x k,h It belongs to the dynamic lane function control strategy, that is, the variable guide lane; if the variable is consistent with the previous cycle, it is taken as the constant value of the previous cycle and substituted into the optimization model; Phase sequence variable y i,i′ Phase sequence scheme adjustment belonging to the adaptive signal control strategy; If the variable is consistent with the previous period, it is taken as the constant value of the previous period and substituted into the optimization model; Signal timing variable t i , g i , g k , C belongs to the green light duration adjustment of the adaptive signal control strategy, which changes once in one signal cycle.

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