Method for planning a traffic plan for a flexible intersection and computer program product

Abstract

The application discloses a kind of flexible intersection traffic scheme planning method and computer program product.It includes: firstly, the time range corresponding to current planning phase, the traffic state information such as the position, speed, acceleration, driving lane and steering of all vehicles first entering control area are collected.Then, based on the traffic state information of all vehicles, the mixed integer linear programming optimization model set is solved, and the traffic scheme corresponding to current planning phase is obtained.The traffic scheme includes the real-time trajectory of each car in the time range of current planning phase, the length of each control partition of sub-intersection control area, lane function, the connection path of sub-intersection lane, the signal timing scheme of sub-intersection, and the traffic design scheme of sub-intersection.According to the traffic scheme, the coordinated control of lane division, trajectory planning, signal timing and partition division is realized, so as to realize the fine management of flat intersection, and maximize the intersection traffic efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of traffic control of road vehicles, in particular to a traffic plan planning method for a flexible intersection and a computer program product. BACKGROUND

[0002] Under the intelligent network environment, the vehicle operation trajectory can be optimized in real time, and the vehicle is ensured to strictly comply with the optimal trajectory driving. The interconnection technology mainly based on vehicle-to-vehicle communication (V2V) and vehicle-to-infrastructure communication (V2I) can obtain the traffic state information such as position, speed, acceleration, driving lane and steering of the vehicle in real time, and centrally control and optimize the position, speed, acceleration and driving lane of each vehicle at each moment. The automatic driving technology mainly based on vehicle trajectory control can realize accurate and stable speed, acceleration, following, lane changing, lane keeping and other horizontal and vertical controls, so as to achieve stable and controllable trajectory control and eliminate the adverse effects of human driving behavior on the design, control and safety of unconventional intersections.

[0003] However, the current interconnection technology and automatic driving technology have the problem of insufficient management refinement of flat intersections, which leads to the fact that the traffic design scheme, signal timing and trajectory planning of the intersection cannot be precisely matched, and the traffic efficiency of the intersection cannot be maximized. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a traffic plan planning method for a flexible intersection and a computer program product, which can solve the problem of insufficient management refinement of flat intersections and maximize the traffic efficiency of the intersection. The specific technical solutions are as follows:

[0005] In a first aspect, a traffic plan planning method for a flexible intersection is provided. In a first implementation manner of the first aspect, the method comprises:

[0006] obtaining traffic state information of each vehicle arriving at a control area of the flexible intersection in a current planning stage;

[0007] solving a mixed integer linear programming optimization model based on the traffic state information of all vehicles to obtain a traffic plan by using a standard branch and bound algorithm;

[0008] The objective function of the mixed integer linear programming optimization model includes a primary optimization target and three secondary optimization targets. The primary optimization target is to minimize the difference between the actual driving time and the free flow driving time. The three secondary optimization targets are to minimize the absolute value of acceleration, to minimize the cycle length and to minimize the number of lane changes of the vehicle. The objective function of the mixed integer linear programming optimization model is specifically:

[0009] ;

[0010] wherein, is a direction, is a set of directions, is a vehicle flow direction, is a vehicle number, is a vehicle flow direction of a vehicle set, is a vehicle passing through a direction corresponding to the time when the dividing line is crossed, is the starting time of trajectory optimization, is the recorded time when the vehicle first enters the control area, is a flow from entering the control area to the final free-flow driving time when leaving the control area, is the interval time between two adjacent phase green lights, is a time step, is a set of time steps, is the vehicle acceleration at a time step, is the cycle length at the main signal, is the cycle length at the pre-signal in the direction , is the minimum comfortable acceleration allowed for the vehicle, is the maximum comfortable acceleration allowed for the vehicle, is the number of planning steps, is a lane number, is a set of lanes in the direction , is whether the vehicle is on the lane at a time step , , are the priority coefficients corresponding to the first-level optimization target and the second-level optimization target, respectively;

[0011] The flexible intersection is an intersection with pre-signals added on the road segments in each direction at the intersection. The flexible intersection uses dynamic reversible lanes and is managed at the lane level through lane number markings on the road surface and lane-level signal lights. Each direction adjusts the use function and driving direction switching scheme of each lane between the main signal and the pre-signal, and adjusts the distribution of the number of lanes for each flow direction in real time.

[0012] The set of directions are west, south, east, and north, respectively.

[0013] The minimum comfortable acceleration is the minimum acceleration that does not affect the comfort of the passengers during vehicle driving;

[0014] ​The maximum comfort acceleration is the maximum acceleration that does not affect the comfort of the passengers during the driving of the vehicle.

[0015] The priority coefficient refers to a priority weighting coefficient of different optimization targets.

[0016] In a second implementation manner of the first aspect, in combination with the first implementation manner of the first aspect, the constraint condition of the mixed integer linear programming optimization model comprises a lane division constraint, and the lane division constraint comprises a buffer zone lane division constraint, a variable guide zone lane division constraint, a comprehensive function zone lane division constraint, a pre-signal intersection lane connection constraint, a main-signal intersection lane connection constraint, and a constraint that only one traffic design scheme is allowed in each direction, and upstream intersection designs need to be symmetrically arranged.

[0017] In a third implementation manner of the first aspect, in combination with the second implementation manner of the first aspect, the comprehensive function zone lane division constraint comprises special requirement constraint conditions corresponding to various traffic design schemes.

[0018] In a fourth implementation manner of the first aspect, in combination with the first implementation manner of the first aspect, the constraint condition of the mixed integer linear programming optimization model comprises a trajectory planning constraint, and the trajectory planning constraint comprises an acceleration variable domain constraint, a speed variable domain constraint, a position variable domain constraint, a sub-intersection connection path matching variable domain constraint, a follow-up and lane-changing behavior safety constraint.

[0019] In a fifth implementation manner of the first aspect, in combination with the first implementation manner of the first aspect, the constraint condition of the mixed integer linear programming optimization model comprises a signal timing constraint, and the signal timing constraint comprises a main-signal phase sequence constraint, a vehicle passing time constraint of a main-signal stop line, a pre-signal phase sequence constraint, and a vehicle passing time constraint of a pre-signal stop line.

[0020] In a sixth implementation manner of the first aspect, in combination with the fifth implementation manner of the first aspect, the pre-signal phase sequence constraint comprises special requirement constraint conditions corresponding to various traffic design schemes.

[0021] In a seventh implementation manner of the first aspect, in combination with the first implementation manner of the first aspect, the constraint condition of the mixed integer linear programming optimization model comprises a sub-zone division constraint, and the sub-zone division constraint comprises a sub-zone length constraint and a sub-intersection vehicle driving trajectory constraint.

[0022] In an eighth implementation manner of the first aspect, in combination with the first implementation manner of the first aspect, solving the mixed integer linear programming optimization model comprises:

[0023] determining whether the planning step number meets an update condition when the traffic plan cannot be obtained by solving the mixed integer linear programming optimization model;

[0024] updating the planning step number and re-solving the mixed integer linear programming optimization model in response to the update condition being met;

[0025] updating the planning vehicle list step number and re-acquiring the traffic state information of each vehicle arriving at the control area of the flexible intersection to solve the mixed integer linear programming optimization model in response to the update condition not being met.

[0026] In a second aspect, a computer program product is provided, comprising computer programs / instructions which, when executed by a processor, implement the steps of the traffic plan planning method according to any one of the first to eighth implementation manners of the first aspect.

[0027] Beneficial effects: The traffic plan planning method and the computer program product for the flexible intersection according to the present application can obtain the optimal traffic plan by solving the set mixed integer linear programming optimization model according to the traffic states of all vehicles arriving at the control area in the current planning stage, realize the cooperative optimization of lane division, design scheme selection, signal timing, vehicle trajectory planning, and sub-intersection lane connection path and partition division, thereby overcoming the problem of insufficient management refinement of the flat intersection, ensuring that the intersection geometric design, signal timing, and trajectory planning closely cooperate to organize traffic in a highly orderly and efficient manner, and maximizing the intersection traffic efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present application, the drawings required to be used in the specific embodiments will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn according to the actual proportions.

[0029] Figure 1 a flowchart of the traffic plan planning method for the flexible intersection provided by an embodiment of the present application;

[0030] Figure 2 a partition and lane marking schematic diagram for a control area of a certain direction of the flexible intersection;

[0031] Figure 3 a schematic diagram of a conventional design traffic plan provided by an embodiment of the present application;

[0032] Figure 4 a schematic diagram of a left-turn traffic plan by borrowing a lane provided by an embodiment of the present application;

[0033] Figure 5 a schematic diagram of an arrayed traffic plan provided by an embodiment of the present application;

[0034] Figure 6 This is a schematic diagram of a continuous circulation scheme provided in an embodiment of the present invention;

[0035] Figure 7 This is a schematic diagram of a parallel circulation scheme provided in an embodiment of the present invention;

[0036] Figure 8 This is a schematic diagram of an upstream cross-traffic scheme provided in an embodiment of the present invention;

[0037] Figure 9 This is a schematic diagram illustrating the operational rules for switching a flexible intersection to a continuous traffic flow scheme. Detailed Implementation

[0038] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0039] It should be understood that in this embodiment, the flexible intersection is a pre-signaled intersection added to the road segments in each direction of the intersection. It can adopt dynamic reversible lanes and manage lanes through road lane number markings and lane-level traffic lights. Each direction can flexibly switch between conventional design, left turn by borrowing lanes, array type, continuous flow, parallel flow, upstream intersection, etc. by adjusting the lane usage function and driving direction between the main signal and the pre-signal. It can also adjust the allocation of the number of driving lanes in each direction in real time.

[0040] A flexible intersection includes multiple sub-intersections, each corresponding to a different direction. Each sub-intersection is equipped with a control area, which is divided into four control zones along the direction towards the intersection convergence area: a buffer zone, a variable guidance zone, a pre-signal intersection, and a comprehensive functional zone.

[0041] In the integrated functional area, each lane is a dynamically reversible lane, which can be dynamically adjusted to a left-turn entry lane, a straight-in lane, a left-turn exit lane, or a straight-out lane according to actual needs during operation. In the variable guidance area, each lane is also a dynamically reversible lane, which can be dynamically adjusted to a left-turn entry lane or a straight-in lane. Lane markings can be used to guide drivers to select designated lanes, thus enabling dynamic adjustment of lanes at the flexible intersection during operation.

[0042] Specifically, such as Figure 2 As shown, It is the direction The length of the control zone allows for optimization of vehicle trajectories. As direction number, They are west, south, east, and north, respectively. is the set of flow directions of vehicles, including straight, east left turn, east straight, north left turn and north straight. is the direction of the upstream intersection, is the set of flow directions at the upstream pre-signal, is the set of vehicle numbers, . is the set of flow directions of vehicles, .

[0043] is the set of partition boundary numbers, . is the set of partition numbers, is the set of flow directions of vehicles, including straight, east left turn, east straight, north left turn and north straight. is the set of lane numbers, , is the set of lanes corresponding to each partition, is the set of lanes in the comprehensive function area, is the set of lanes in the variable guidance area, is the set of lanes in the buffer area.

[0044] is the set of lane numbers, , the lane number is used for lane division constraint construction, and the lane number is not affected by the partition, that is, the number of each lane in the direction is always , which is used for trajectory planning constraint construction. is the time step, .

[0045] The lengths of the buffer area, the variable guidance area, the pre-signal intersection and the comprehensive function area can be adjusted in real time according to the needs of traffic management. The upstream vehicles randomly select the lanes that can be driven into the control area without considering the intersection turning, and the variable guidance area requires left turn and straight turn to select their own dedicated lanes, so a buffer area is needed for transition. The difference between the buffer area and the variable guidance area is that left turn and straight turn need to share lanes.

[0046] It should also be understood that, as shown in Figures 3-8 , the embodiment designs 6 intersection passing design schemes, including regular design, left turn by borrowing lane, array type, continuous flow, parallel flow and upstream intersection. By combining the variable guidance area, the pre-signal intersection and the comprehensive function area, the lane driving direction and the function are changed, that is, the passing design scheme corresponding to each sub-intersection of the flexible intersection can be switched. In the embodiment, is the set of flow directions of vehicles, including straight, east left turn, east straight, north left turn and north straight. is the set of flow directions of vehicles, including straight, east left turn, east straight, north left turn and north straight.

[0047] Specifically, the upstream vehicles select the travel lane from the entrance side to enter the buffer zone into the driveway, and the exit vehicles from the buffer zone into the downstream section. The left-turn driveway and the straight driveway share the same lane, and the left-turn exit and the straight exit share the same lane, and the vehicles can freely change lanes. The driveway in the variable guidance zone operates according to the same rule as the buffer zone, and the left-turn driveway and the straight driveway require to select the respective dedicated lane to travel, and the vehicles cannot change lanes in the driveway. The pre-signal separates the time to eliminate the conflict between different directions in the variable guidance zone and the comprehensive function zone.

[0048] For example Figure 9 The left-turn driveway and the straight exit in the continuous flow are shown. The comprehensive function zone can be dynamically adjusted to the corresponding geometric layout of the continuous flow according to the traffic management needs. In the sub-intersection, each lane can have different connection paths, for example, in the direction The lane may be connected to the lane , so there are possible connection paths in the sub-intersection. The vehicles automatically select the connection path with the shortest travel time under the constraint condition in each sub-intersection.

[0049] The length, lane division and operation rules of the comprehensive function zone, the variable guidance zone and the buffer zone are set by the intersection control unit, and are issued to the designated vehicles by the roadside control unit, requiring each direction vehicle to travel in the designated lane and to change lanes at where, so as to realize the dynamic switching of the design scheme of the flexible intersection in each direction. The virtual signal lamp can be set at the pre-signal to eliminate the conflict between each direction by time separation. If there are pedestrians crossing the street at the main signal, the entity signal lamp needs to be set to ensure the safety of the pedestrians crossing the street, otherwise only the virtual signal lamp can be set.

[0050] The flow chart of the traffic plan planning method of the flexible intersection is shown in Figure 1 The planning method includes:

[0051] Step 1, obtaining the traffic state information of each vehicle arriving at the control zone of the flexible intersection in the current planning stage;

[0052] Step 2, based on the traffic state information of all vehicles, a standard branch and bound algorithm is used to solve a mixed integer linear programming optimization model to obtain a traffic plan;

[0053] The objective function of the mixed integer linear programming optimization model includes a primary optimization target and three secondary optimization targets, the primary optimization target is to minimize the difference between the actual travel time and the free flow travel time, the three secondary optimization targets are to minimize the absolute value of acceleration, to minimize the cycle length and to minimize the number of lane changes, and the objective function of the mixed integer linear programming optimization model is specifically:

[0054] ;

[0055] Wherein, is a direction, is a direction set, is a vehicle flow direction, is a vehicle number, is a vehicle flow direction vehicle set, is a vehicle passing through the direction midline corresponding time, is the starting time of trajectory optimization, is the recorded time when the vehicle first enters the control area, is the free flow travel time from entering the control area to finally leaving the control area, is the green interval time between two adjacent phases, is a time step, is a time step set, is the vehicle acceleration at the time step, is the cycle length at the main signal, is the cycle length at the pre-signal in the direction , is the minimum comfortable acceleration allowed by the vehicle, is the maximum comfortable acceleration allowed by the vehicle, is the planning step number, is a lane number, is a lane set in the direction , is whether the vehicle is on the lane at the time step , , , are the priority coefficients corresponding to the primary optimization target and the secondary optimization targets respectively;

[0056] ​The flexible intersection is an intersection with pre-signals added on road segments in each direction of the intersection. The flexible intersection uses dynamic reversible lanes and manages lanes through lane number markings on the road surface and lane-level signal lights. Each direction adjusts the use of each lane between the main signal and the pre-signal and switches the traffic direction passing scheme, and adjusts the number of lanes for each flow in real time.

[0057] The direction set West, south, east and north, respectively.

[0058] The minimum comfortable acceleration is the minimum acceleration that does not affect the comfort of the passengers during vehicle travel.

[0059] The maximum comfortable acceleration is the maximum acceleration that does not affect the comfort of the passengers during vehicle travel.

[0060] The priority coefficient is the priority weighting coefficient of different optimization objectives.

[0061] Specifically, first, the position, speed, acceleration, travel lane and turning of all vehicles entering the control area for the first time in the time range corresponding to the current planning stage can be collected. Then, based on the traffic state information of all vehicles, the mixed integer linear programming optimization model composed of the above-mentioned objective function and the pre-set constraint conditions is solved, so as to obtain the passing scheme corresponding to the current planning stage.

[0062] The passing scheme includes the real-time trajectory of each car in the time range of the current planning stage, the length of each control partition of the sub-intersection control area, the lane function, the connection path of the sub-intersection lane, the signal timing scheme of the sub-intersection, and the passing design scheme of the sub-intersection. The centralized controller can realize the coordinated control of lane division, trajectory planning, signal timing, and partition division according to the passing scheme, so as to realize the fine management of the planar intersection and maximize the intersection passing efficiency.

[0063] The main objective of the optimization model is to reduce vehicle delay, so the first-level optimization objective is vehicle delay, as shown in the first term of the objective function. Vehicle delay is the difference between actual travel time and free flow travel time. The actual travel time is calculated as the difference between the time when the vehicle enters the control area and the time when it finally leaves the control area.

[0064] If only vehicle delay is used as the optimization objective, there may be a large number of passing schemes with the same target value, some of which are even unreasonable passing schemes. Therefore, the optimization model of the present application further introduces two secondary optimization objectives to further select the optimal scheme in the solution with the minimum vehicle delay.

[0065] One of the secondary optimization objectives is to minimize the absolute value of acceleration, see the second term of the objective function. Acceleration can be regarded as vehicle fuel consumption on the one hand, and represents the ride comfort of the passengers on the other hand. Another secondary optimization objective is to minimize the cycle length, see the third term of the objective function. The smaller the cycle length of each sub-intersection, the earlier the next stage planning signal timing can start, and thus the less impact on the next stage planning signal timing. The last secondary optimization objective is to minimize the number of vehicle lane changes, see the fourth term of the objective function, aiming to avoid unnecessary lane changes of vehicles. The first and second optimization objectives are weighted by priority coefficients 、 adjustment, much greater than . Considering that there are a large number of summation functions in each term of the objective function, in order to avoid the influence of each summation on the priority coefficient, the average value is multiplied by the priority coefficient.

[0066] In this embodiment, optionally, the constraint conditions of the mixed integer linear programming optimization model include lane division constraints, which include buffer zone lane division constraints, variable guide zone lane division constraints, comprehensive function zone lane division constraints, pre-signal intersection lane connection constraints, main signal intersection lane connection constraints, and only one traffic design scheme is allowed in each direction, and the upstream intersection design needs to be symmetrically set.

[0067] Specifically, the constraint conditions set by the mixed integer linear programming optimization model can include lane division constraints, buffer zone lane division, variable guide zone lane division, comprehensive function zone lane division, pre-signal intersection lane connection, main signal intersection lane connection, and five aspects of lane division constraints.

[0068] (1) The buffer zone lane division constraint includes:

[0069] Each lane of the buffer zone is allowed to have at least one vehicle flow, and the specific expression is:

[0070] ;

[0071] Each vehicle flow in the buffer zone has at least one lane for driving, and the specific expression is:

[0072] ;

[0073] The left turn into and straight driving into the buffer zone need to share lanes, and the left turn out and straight driving out need to share lanes, and the specific expression is:

[0074] ;

[0075] The entering vehicle flow and the exiting vehicle flow are not allowed to share lanes, and the specific expression is:

[0076] ;

[0077] The left-turn exit and straight exit lane is located on the left side of the left-turn entry and straight entry lane, and the specific expression is:

[0078] ;

[0079] To ensure that the vehicle on the entrance side lane outside the control area smoothly enters the buffer zone, it is required that the buffer zone matching lane is set as the entry lane, and the specific expression is:

[0080] ;

[0081] At the same time, each sub-intersection is required to adopt only one traffic design scheme, and needs to be symmetrically arranged with the traffic design scheme of the upstream intersection, and the specific expression is:

[0082] ;

[0083] ;

[0084] wherein, is the direction whether to adopt the traffic design scheme , indicates adoption, indicates non-adoption, is the direction whether to adopt the traffic design scheme , is the direction whether to adopt the traffic design scheme . indicates lane marking, indicates allowed flow direction using , indicates disallowed flow direction using .

[0085] (2) The lane division constraints of the variable guidance zone include:

[0086] Each lane in the variable guidance zone is allowed to have at least one vehicle flow, and the specific expression is:

[0087] ;

[0088] Each vehicle flow has at least one lane for driving, and the specific expression is:

[0089] ;

[0090] For left turns and straight exits, the corresponding lane markings in the variable guidance zone and buffer zone are the same, as shown in the following expression:

[0091] ;

[0092] For left turns and straight entries within the variable guidance zone, the lane markings must not be larger than the corresponding lane markings in the buffer zone. The specific expression is:

[0093] ;

[0094] Left turns and straight-through traffic are not allowed to share lanes. The specific expression is as follows:

[0095] ;

[0096] In all design schemes except for parallel flow, the left-turn lane is located to the left of the straight-in lane, as shown in the following expression:

[0097] ;

[0098] If a parallel flow design is adopted, the straight-in lane is located to the left of the left-turn lane, and the specific expression is:

[0099] ;

[0100] in, Indicates permitted flow direction Use lane , Indicates permitted flow direction Use lane , For the first One possible design scheme is the parallel flow design scheme.

[0101] (3) Comprehensive functional area lane division constraints. In this embodiment, the comprehensive functional area lane division constraints may optionally include special requirements and constraints corresponding to various traffic design schemes.

[0102] Specifically, considering the special requirements of the above six traffic design schemes for the lane division of the comprehensive functional area, in addition to the common constraints of these six traffic design schemes, special requirement constraints of each traffic design scheme can also be constructed separately.

[0103] The shared constraint requires that each lane allows at least one traffic flow, and each traffic flow has at least one lane available for travel. The specific expression is as follows:

[0104] ;

[0105] ;

[0106] For the conventional design, the special requirement constraints include: the same corresponding lane marking in the comprehensive function zone and the variable guidance zone for each flow direction, specifically expressed as:

[0107] ;

[0108] For the left turn using the adjacent lane, the special requirement constraints include: the same corresponding lane marking in the comprehensive function zone and the variable guidance zone for the straight driving in, the left turn driving out and the straight driving out, specifically expressed as:

[0109] ;

[0110] And, the same corresponding lane marking in the comprehensive function zone and the variable guidance zone on the import side for the left turn driving in, specifically expressed as:

[0111] ;

[0112] Also, the left turn driving in preferentially uses the exit lane close to the central separation belt, specifically expressed as:

[0113] ;

[0114] For the array type, the special requirement constraints include: the same corresponding lane marking in the comprehensive function zone and the variable guidance zone for the left turn driving out and the straight driving out, specifically expressed as:

[0115] ;

[0116] And, the lane marking in the comprehensive function zone is not less than the corresponding lane in the variable guidance zone for the left turn driving in and the straight driving in, specifically expressed as:

[0117] ;

[0118] Also, the same corresponding lane marking in the comprehensive function zone and the variable guidance zone on the exit side for the left turn driving in and the straight driving in, specifically expressed as:

[0119] ;

[0120] The left turn driving in preferentially uses the import lane close to the central separation belt, specifically expressed as:

[0121] ;

[0122] The straight driving in preferentially uses the import lane close to the road side, specifically expressed as:

[0123] ;

[0124] For continuous flow, the special requirement constraints include:

[0125] Straight entering in the same corresponding lane marking in the comprehensive function area and variable guidance area, the specific expression is:

[0126] ;

[0127] And, left turn entering, straight entering and straight exiting do not share the lane, the specific expression is:

[0128] ;

[0129] Also, left turn exiting and straight exiting need to share the lane, the specific expression is:

[0130] ;

[0131] Left turn entering lane is located on the left side of straight exiting lane, straight exiting lane is located on the left side of straight entering lane, the specific expression is:

[0132]

[0133] For parallel flow, the special requirement constraints include:

[0134] Left turn entering in the same corresponding lane marking in the comprehensive function area and variable guidance area, the specific expression is:

[0135] ;

[0136] And, each flow direction is not allowed to share the lane, the specific expression is:

[0137] ;

[0138] Also, straight exiting lane is located on the left side of straight entering lane, straight entering lane is located on the left side of left turn exiting lane, left turn exiting lane is located on the left side of left turn entering lane, the specific expression is:

[0139] ;

[0140] For upstream intersection, the special requirement constraints include:

[0141] Left turn entering, straight entering and straight exiting do not share the lane, the specific expression is:

[0142] ;

[0143] And, left turn exiting and straight exiting need to share the lane, the specific expression is:

[0144] ;

[0145] Also, the left-turn entry lane is located on the left side of the straight entry lane, and the straight entry lane is located on the left side of the straight exit lane, which is expressed as:

[0146] ;

[0147] Among them, Indicates two different flow directions,

[0148] (4) The lane connection constraints of the pre-signal intersection include:

[0149] The number of approaching lanes of each flow direction is not greater than the number of receiving lanes, which is expressed as:

[0150] ;

[0151] ;

[0152] ;

[0153] Only when a certain approaching lane and a certain receiving lane are allowed to be used by a certain flow at the same time can they be connected, which is expressed as:

[0154] ;

[0155] ;

[0156] Except for the borrowed left turn and the array design, the two connection paths of the left-turn entry of the remaining designs cannot intersect, which is expressed as:

[0157]

[0158] Except for the array design, the two connection paths of the straight entry of the remaining designs cannot intersect, which is expressed as:

[0159] ;

[0160] The two connection paths of the left-turn exit and the straight exit cannot intersect, which is expressed as:

[0161] ;

[0162] Except for the borrowed left turn and the array design, each approaching lane of the left-turn entry of the remaining designs has only one connection path, which is expressed as:

[0163]

[0164] Except for the array design, each approaching lane of the straight entry of the remaining designs has only one connection path, which is expressed as:

[0165]

[0166] Each receiving lane for left turns and straight-through traffic has no more than one connecting path, specifically expressed as follows:

[0167] ;

[0168] Each approach lane for left turns and straight exits has only one connecting path, and each receiving lane has no more than one connecting path. The specific expression is as follows:

[0169] ;

[0170] ;

[0171] Based on the operational rules of the left-turn entry design using a shared left-turn lane, the left-turn entry design using a queuing approach, and the straight-through entry, it can be seen that the above traffic flow involves one approach lane connected to multiple receiving lanes. To avoid conflicts, time separation is used, therefore each approach lane has at least one connecting path. The specific expression is as follows:

[0172] ;

[0173] In the design of left-turn lanes using shared lanes, the regular left-turn lanes in the integrated functional area must be connected to the corresponding lanes in the variable guidance area. The specific expression is as follows:

[0174] ;

[0175] In a layout design, if an entry lane in the integrated functional area is not a shared lane for left turns and straight-through entry, then the corresponding lane in the variable guidance area must be connected. The specific expression is as follows:

[0176] ;

[0177] in, , Indicates different lanes, This indicates the permitted flow direction at the intersection. From the lane Enter the lane , This indicates that the flow is not allowed. From the lane Enter the lane , This indicates the permitted flow direction at the intersection. From the lane Enter the lane , This indicates that the flow is not allowed. from the lane drive into the lane .

[0178] (5) The lane connection constraint of the main signalized intersection includes:

[0179] The number of approaching lanes of each flow direction is not greater than the number of receiving lanes, and the specific expression is:

[0180] ;

[0181] ;

[0182] Only when a certain approaching lane and a certain receiving lane are allowed to be used by a certain flow direction at the same time, the two lanes can be connected, and the expression is:

[0183] ;

[0184] ;

[0185] The connection paths of two lanes of the main signalized intersection cannot intersect, and the specific expression is:

[0186] ;

[0187] ;

[0188] Each approaching lane has only one connection path, and each receiving lane has no more than one connection path, and the specific expression is:

[0189] ;

[0190] ;

[0191] ;

[0192] .

[0193] In this embodiment, optionally, the constraint condition of the mixed integer linear programming optimization model includes a trajectory planning constraint, and the trajectory planning constraint includes an acceleration variable domain constraint, a speed variable domain constraint, a position variable domain constraint, a sub-intersection connection path matching variable domain constraint, a lane selection variable domain constraint, and a following and lane changing behavior safety constraint.

[0194] Specifically, the constraint condition of the mixed integer linear programming optimization model can further include a trajectory planning constraint. The trajectory planning constraint can be constructed from an acceleration variable domain, a speed variable domain, a position variable domain, a sub-intersection connection path matching variable domain, a lane selection variable domain, and a following and lane changing behavior safety condition.

[0195] 1. Acceleration variable domain constraint, including:

[0196] The acceleration of all vehicles is limited in the minimum and maximum comfortable acceleration range, and the specific expression is:

[0197] ;

[0198] The vehicle travels at a constant speed in the sub-intersection, so the acceleration in the sub-intersection is equal to 0, and the specific expression is:

[0199] ;

[0200] ;

[0201] ;

[0202] ;

[0203] The vehicle passes through each boundary line at a constant speed, so the acceleration of the vehicle passing through each boundary line is equal to 0, and the specific expression is:

[0204] .

[0205] 2. Speed variable domain constraint, including:

[0206] The initial speed of the vehicle is assigned to the most recent time step after the vehicle enters the control area, combined with the recorded driving speed when the vehicle first enters the control area, and the specific expression is:

[0207] ;

[0208] wherein, represents the upward rounding.

[0209] The driving speed of all vehicles is limited to be positive and cannot be greater than the limit speed, and the specific expression is:

[0210] ;

[0211] According to the vehicle dynamics equation, update all vehicle speeds using acceleration, and the specific expression is:

[0212] ;

[0213] The vehicle travels at a constant speed in the sub-intersection, and the speed is determined by the radius of the two lane connection paths, and the specific expression is:

[0214] ;

[0215] ;

[0216] ;

[0217] ;

[0218] 3. Position variable domain constraint, including:

[0219] Assign the position initial value to the nearest time step after the vehicle enters the control area, combined with the recorded travel speed when the vehicle first enters the control area, and the specific expression is:

[0220] ;

[0221] Update all vehicle positions using acceleration and speed, and the specific expression is:

[0222] ;

[0223] ;

[0224] ;

[0225] ;

[0226] Let the position of the vehicle in the sub-intersection be a constant value, and the specific expression is:

[0227] ;

[0228] .

[0229] 4. Partition passing time variable domain constraint, including:

[0230] Assign the time initial value to the vehicle first passing the boundary line combined with the recorded time when the vehicle first enters the control area, and the specific expression is:

[0231] ;

[0232] The relationship between the time when the vehicle passes each boundary line and the auxiliary variable , and the specific expression is:

[0233] ;

[0234] If the vehicle passes each boundary line at a constant speed, then the time when the vehicle first passes the boundary line , and the time when the vehicle secondly passes the boundary line are related to the position of the nearest time step when entering the boundary line, and the specific expression is:

[0235] ;

[0236] ;

[0237] ;

[0238] ;

[0239] The moment when the vehicle first passes the boundary line and the moment when the vehicle secondly passes the boundary line , and the relationship between the moment when the vehicle first passes the boundary line

[0240] ;

[0241] ;

[0242] ;

[0243] ;

[0244] The vehicle travels at a constant speed in the sub-intersection, so the relationship between the moment when the vehicle enters the sub-intersection and the moment when the vehicle leaves the sub-intersection, the specific expression is:

[0245] ;

[0246] ;

[0247] ;

[0248] ;

[0249] Considering that the travel speed of the vehicle first passing the boundary line and the vehicle secondly passing the boundary line , is unknown, if the above constraints are still used, there will be nonlinear constraints. Since the actual moment when the vehicle first passes the boundary line and the vehicle secondly passes the boundary line does not affect the travel time, the following expression constraints , are introduced to ensure between the two time steps before and after the vehicle passes the boundary line, the specific expression is:

[0250] ;

[0251] ;

[0252] For vehicles crossing the dividing line a second time The actual moment of departure directly determines the travel time. Considering the vehicle leaving the sub-intersection and entering the variable guidance zone and buffer zone, based on minimizing the travel time, it will definitely accelerate to leave the control zone as quickly as possible. Since both the variable guidance zone and buffer zone have minimum length restrictions, it is assumed that the vehicle accelerates to the dividing line after passing through the variable guidance zone and buffer zone. and at maximum speed Passing through is reasonable; the following formula is used to determine the dividing line for the vehicle's second passage. The actual moment:

[0253]

[0254] And the following constraints exist:

[0255] ;

[0256] The partitioning also includes constraints on the time variable domain, requiring all vehicles to leave the control area within the planned number of steps. The specific expression is:

[0257] ;

[0258] ;

[0259] The vehicles cross each dividing line in a specific order, as expressed in the following formula:

[0260] ;

[0261] ;

[0262] in, Indicates time step Vehicle Has the direction been passed? The dividing line , Indicates the process, This indicates that it has not been done. For time steps Vehicle driving speed, For a moment Vehicles recorded in time driving speed, For time step, For direction Maximum speed allowed Indicates vehicles at the sub-intersection From the lane Enter the lane , denotes the lane from which the vehicle enters the lane denotes the lane from which the vehicle enters the lane , denotes the lane from which the vehicle enters the lane denotes the lane from which the vehicle enters the lane .

[0263] denotes the driving speed of the vehicle in the sub-intersection from the lane denotes the lane from which the vehicle enters the lane , denotes the distance of the vehicle from the stop line in the direction at the time step , takes a positive value if the vehicle is located on the link and a negative value if the vehicle is located at the main signal.

[0264] denotes the maximum positive value, denotes the direction the distance of the partition boundary from the stop line, denotes the time instant when the vehicle passes the boundary in the direction . denotes the driving time of the vehicle in the sub-intersection from the lane denotes the lane from which the vehicle enters the lane .

[0265] 5. Lane selection variable domain constraints, including:

[0266] assigns the lane selection initial value to the vehicle at the nearest time step after the vehicle enters the control zone, in combination with the driving lane recorded when the vehicle first enters the control zone, and the specific expression is:

[0267] ;

[0268] the vehicle is in the lane changing state, and at this time instant, it occupies the current lane and the target lane, otherwise it can only occupy one lane, and the specific expression is:

[0269] ;

[0270] maintains the lane selection of the vehicle unchanged outside the control zone, in the sub-intersection and on the entrance side of the variable guidance zone, and the specific expression is:

[0271] ;

[0272] ;

[0273] ;

[0274] ​​​​ ;

[0275] ;

[0276] ;

[0277] The vehicle can only change lanes to the adjacent lane of the current lane, and the specific expression is:

[0278] ;

[0279] ;

[0280] If the vehicle does not change lanes at the current time, the lane to which the vehicle belongs at the next time is the same as the current time, and the specific expression is:

[0281] ;

[0282] ;

[0283] If the vehicle changes lanes at the current time, the lane to which the vehicle belongs at the next time is the same as the target lane after changing lanes at the current time, and the specific expression is:

[0284] ;

[0285] ;

[0286] The vehicle cannot continuously change lanes, and a certain time interval is required between two lane changing behaviors, and the specific expression is:

[0287] ;

[0288] Only a certain flow direction is allowed to use a certain lane, and the vehicle of the flow direction can be allowed to occupy, and the specific expression is:

[0289] ;

[0290] ;

[0291] In the design of left-turn vehicles dynamically borrowing exit lanes, the left-turn vehicles are required to enter the borrowed exit lane from the entrance side lane at the pre-signal, and cannot change lanes across the middle strip in the comprehensive function area, and the specific expression is:

[0292] .

[0293] 6. The sub-intersection connection path matching variable domain constraint includes:

[0294] The selected driving lane of the vehicle entering and leaving the sub-intersection should be the lane at the two ends of the allowed connecting path, and the specific expression is:

[0295] ;

[0296] ;

[0297] ;

[0298] ;

[0299] ;

[0300] ;

[0301] ;

[0302] ;

[0303] Each vehicle can only select one connecting path at each sub-intersection, and the specific expression is:

[0304] ;

[0305] ;

[0306] ;

[0307] ;

[0308] Only a certain connecting path is allowed to be used by a certain flow direction, and the vehicle of the flow direction can be allowed to occupy, and the specific expression is:

[0309] ;

[0310] ;

[0311] ;

[0312] .

[0313] 7、Car-following and lane-changing behavior safety condition constraints, to meet the requirement of safe driving, the current vehicle should keep at least a minimum safety gap with the front vehicle, the car-following behavior safety condition for the design of flexible intersection is given. Similarly, under the premise that the distance between the front and rear vehicles in the adjacent lane meets the safety requirement of the current vehicle for lane-changing, the current vehicle can choose to change lanes to the adjacent lane. That is, the current vehicle meets the lane-changing behavior safety condition when the current lane and the target lane both meet the car-following behavior safety condition before, during and after lane-changing, and the current vehicle is allowed to change lanes to the adjacent lane according to the need. Therefore, the car-following and lane-changing behavior safety condition constraints are as follows:

[0314] ;

[0315] ;

[0316] ;

[0317] .

[0318] wherein, is the record of whether the vehicle is in the lane at time , represents that the vehicle is in the lane, represents that the vehicle is not in the lane. represents whether the vehicle is in the lane at time step , represents whether the vehicle is in the lane at time step , represents the minimum time interval between two lane changes, represents another time step, represents the total number of lanes in the direction , represents the minimum distance between the front and rear vehicles in the adjacent lane, represents the length of the vehicle , represents the minimum safety time interval for car-following, represents whether the vehicle passes the boundary line in the direction at time step , represents the distance of the vehicle from the stop line in the direction at time step . ​​​​

[0319] In the embodiment, the constraint condition of the mixed integer linear programming optimization model includes a signal timing constraint, and the signal timing constraint includes a main signal phase sequence constraint, a vehicle passing through a main signal stop line time constraint, a pre-signal phase sequence constraint, and a vehicle passing through a pre-signal stop line time constraint.

[0320] Specifically, the constraint condition of the mixed integer linear programming optimization model further includes a signal timing constraint, and the signal timing constraint can be constructed from a main signal phase sequence, a vehicle passing through a main signal stop line time, a pre-signal phase sequence, and a vehicle passing through a pre-signal stop line time.

[0321] (1) The main signal phase sequence constraint includes:

[0322] In the conventional design, there are 16 interlaced points, 4 merging points, and 4 diverging points between the left turn and the straight line at the main signal. Since the left turn and the straight line do not share a lane, the diverging point is not a traffic conflict point, and thus a conventional traffic conflict matrix is obtained:

[0323] ;

[0324] The conventional traffic conflict matrix is modified to obtain a traffic conflict matrix of the flexible intersection in combination with the operation rules of the left turn by borrowing a lane, the array type, the continuous flow, the parallel flow, and the upstream intersection. The specific expressions of the operation rules are as follows:

[0325] ;

[0326] ;

[0327] ;

[0328] ;

[0329]

[0330] The specific expression of the traffic conflict matrix of the flexible intersection is:

[0331] .

[0332] The main signal phase sequence constraint further includes:

[0333] The start time and the end time of each phase should be between the start time and the end time of the signal timing optimization, and the specific expression is:

[0334] ;

[0335] .

[0336] The green light duration limit is not less than 0, and the specific expression is: .

[0337] The minimum emptying time after the green light, that is, the yellow light time or the red light transition time, should ensure that all connection paths used by the flow direction can be safely emptied, and the specific expression is:

[0338] ;

[0339] .

[0340] The automatically generated signal phase sequence scheme at the main signal is feasible, and the specific expression is:

[0341] ;

[0342] .

[0343] (2) Vehicle passing through the main signal stop line time constraint, including:

[0344] The time when the vehicle enters the main signal should be during the green light release period of the flow direction, and the specific expression is:

[0345] .

[0346] The vehicle should leave the main signal before the end time of the phase of the flow direction, and the specific expression is:

[0347] ;

[0348] .

[0349] To avoid affecting the next stage vehicle traffic, the release duration of the main signal in this period should not be greater than the range duration of the planned vehicle list, and the specific expression is:

[0350] .

[0351] (3) Pre-signal phase sequence constraints, considering the special requirements of 6 traffic design schemes for pre-signal phase sequence, and constructing constraint conditions composed of common constraints and special requirements constraints of each design scheme.

[0352] Among them, the common constraint of the 6 traffic design schemes is that the start time and end time of each flow direction phase should be between the start time and end time of the signal timing optimization, and the specific expression is:

[0353] ;

[0354] ;

[0355] .

[0356] For the conventional design, the conventional design has no pre-signal intersection, and the pre-signal can be essentially regarded as a virtual sub-intersection with the release signal of each flow direction being always evergreen. Therefore, the constraint conditions of the conventional design include:

[0357] The green light start time is the same as the signal timing optimization start time, the green light duration is equal to the cycle duration, and the minimum clearance time after the green light is, and the specific expression is:

[0358] ;

[0359] ;

[0360] .

[0361] For the left turn by borrowing, the constraint conditions of the special requirements include:

[0362] In addition to the dynamic borrowing of the exit lane, the green light duration of the remaining flow direction is always equal to the cycle duration, and the specific expression is:

[0363] ;

[0364] ;

[0365] .

[0366] The dynamic borrowing of the exit lane by the left turn flow should be completed after the exit flow is cleared, and it should not affect the use of the exit lane by the next phase flow, and the specific expression is:

[0367] ;

[0368] .

[0369] The start time and green light duration of the left turn flow borrowing the exit lane should be within a reasonable range, and the specific expression is:

[0370] ;

[0371] .

[0372] For the row array type, the constraint conditions of the characteristic requirements include:

[0373] The green light duration of the left turn exit and the straight exit is equal to the cycle duration, and the specific expression is:

[0374] ;

[0375] ;

[0376] .

[0377] The left-turn entry and the straight entry cannot overlap in the release period at the pre-signal, and the release sequence is consistent with that at the main signal, and the specific expression is:

[0378] ;

[0379] .

[0380] The minimum clearance time after the green light of the left-turn entry and the straight entry ends should ensure that all the connecting paths used by the flow can be safely cleared, and the specific expression is:

[0381] .

[0382] In the manual driving environment, in order to ensure driving safety, it is usually required that the pre-signal releases another flow of vehicles only after the comprehensive function area is cleared, which will cause a certain loss of traffic capacity. In the CAV environment, it is only required to ensure that all vehicles of the first released flow are always located before the second released flow in the comprehensive function area, and the specific expression is:

[0383] .

[0384] For continuous flow, the special requirement constraint conditions include:

[0385] The green light duration of the straight entry is equal to the cycle duration, and the specific expression is:

[0386] ;

[0387] ;

[0388] .

[0389] The left-turn entry and the left-turn exit cannot overlap in the release period at the pre-signal, and the specific expression is:

[0390] ;

[0391] .

[0392] The minimum clearance time after the green light of the left-turn entry and the left-turn exit ends should ensure that all the connecting paths used by the flow can be safely cleared, and the specific expression is:

[0393] ;

[0394] .

[0395] The release period of left-turning outflow is the same as that of straight outflow, and the specific expression is:

[0396] ;

[0397] ;

[0398] .

[0399] For parallel flow, the constraint conditions required by its characteristics include:

[0400] The green light duration of left-turning inflow and straight outflow is equal to the cycle duration, and the specific expression is:

[0401] ;

[0402] ;

[0403] .

[0404] The release period of straight inflow and left-turning outflow at the pre-signal cannot overlap, and the specific expression is:

[0405] ;

[0406] .

[0407] The minimum clearance time after the green light of straight inflow and left-turning outflow ends should ensure that all the connecting paths used by this flow can be safely cleared, and the specific expression includes:

[0408] ;

[0409] .

[0410] For upstream intersection, the corresponding constraint conditions required by its characteristics include:

[0411] The release period of left-turning inflow and left-turning outflow at the pre-signal cannot overlap, and the specific expression is:

[0412] ;

[0413] .

[0414] The minimum clearance time after the green light of left-turning inflow and left-turning outflow ends should ensure that all the connecting paths used by this flow can be safely cleared, and the specific expression is:

[0415] ;

[0416] .

[0417] The left-turn exit time is the same as the straight-ahead exit time, and the left-turn entry time is the same as the straight-ahead entry time, and the specific expression is:

[0418] ;

[0419] ;

[0420] .

[0421] (4) Vehicle passing through the pre-signal stop line time constraint, including:

[0422] In addition to the left-turn entry and straight-ahead entry of the array design, the vehicle should enter the pre-signal during the green light release period of the flow direction, and the specific expression is:

[0423] ;

[0424] .

[0425] The vehicle should leave the pre-signal before the end time of the flow direction phase, and the specific expression is:

[0426] ;

[0427] .

[0428] In addition to the above constraints, there is a situation where one approach lane is connected to multiple receiving lanes in the left-turn entry of the left-turn design and the left-turn entry and straight-ahead entry of the array design. In the left-turn design, the left-turn entry should be selected to enter the exit lane during the dynamic borrowing release period, and the specific expression is:

[0429] .

[0430] In the array design, the left-turn entry and straight-ahead entry select to drive in the very green lane in the variable guide area, and the entering and leaving sub-intersection time should be during the release period of the phase of the flow direction, and the specific expression is:

[0431] ;

[0432] .

[0433] Select to drive in the always green lane in the variable guide area and enter the comprehensive function area corresponding to the same lane, and the entering and leaving sub-intersection time can be within the entire signal cycle time range, and the specific expression is:

[0434] .

[0435] If the evergreen lane is selected to drive in the variable guidance area and the non-corresponding lane in the comprehensive function area is entered, the time of entering and leaving the sub-intersection should be during the release period of the flow direction phase, and the specific expression is:

[0436] ;

[0437] .

[0438] If two vehicles are in the sub-intersection at the same time, the selected connection path should not intersect, and the specific expression is:

[0439] ;

[0440] .

[0441] wherein, represents other flow directions different from the flow direction , represents the traffic design scheme , represents the conflict correction of the flow direction , respectively represents elimination, no change, and increase. represents whether the direction adopts the traffic design scheme , respectively represents no and yes.

[0442] represents whether the green light start time of the flow direction at the pre-signal of the direction is earlier than the green light start time of the flow direction , . represents the optimization start time of the main signal timing, represents the green light start time of the flow direction at the main signal, represents the green light duration of the flow direction at the main signal, represents the minimum clearance time after the green light of the flow direction at the main signal.

[0443] represents whether the green light start time of the flow direction at the main signal is earlier than the green light start time of the flow direction , represents the green light start time of the flow direction Does the green light start earlier than the flow of people? morning, Indicates the flow direction at the main signal. Does the green light start earlier than the flow direction? morning, Indicates the flow direction at the main signal point of the flexible intersection. With flow direction Is there a conflict? Indicates the flow direction at the main signal point of the flexible intersection. With flow direction Is there a conflict? Indication and flow direction , Other different flow directions. Indicates direction The optimized start time for signal timing at the upper pre-signal location. Indicates flow direction In direction Green light duration at the upper signal point Indicates direction Flow direction at the upper pre-signal Minimum clearing time after the green light ends. Indicates direction The duration of the period at the upper pre-signal.

[0444] Indicates direction Boundary lines of each control zone Distance from the parking line Indicates the direction of flow when turning left. When the green light at the pre-signal borrowed exit turns on. Indicates the flow direction in the design of turning left by detour During the green light duration at the pre-signal borrowed exit, Indicates direction Flow direction at the upper pre-signal The moment the green light turns on, Indicates direction Flow direction at the upper pre-signal Green light duration, Indicates direction Flow direction at the upper pre-signal Minimum clearing time after the green light ends. Indicates vehicles at the sub-intersection From the lane Enter the lane , Indicates vehicle With vehicles Are they simultaneously at the first sub-intersection? These represent "no" and "yes," respectively. , are respectively the total number of lanes on the entrance side and the total number of lanes on the exit side outside the control area.

[0445] In this embodiment, the constraint condition of the mixed integer linear programming optimization model includes a partition division constraint, which includes a partition length constraint and a sub-intersection vehicle travel trajectory constraint.

[0446] Specifically, the constraint condition of the mixed integer linear programming optimization model further includes a partition division constraint. This embodiment constructs the partition division constraint condition from the partition length and the sub-intersection vehicle travel trajectory.

[0447] ①The partition length constraint includes:

[0448] The partition length constraint is constructed according to the relationship between the distance of the boundary line from the stop line and the partition length. The distance of the boundary line from the stop line is the length of the control area, which is equal to the sum of the lengths of the comprehensive function area, the pre-signal intersection, the variable guidance area, and the buffer area. The distance of the boundary line from the stop line is equal to the sum of the lengths of the comprehensive function area, the pre-signal intersection, and the variable guidance area. The distance of the boundary line from the stop line is equal to the sum of the lengths of the comprehensive function area and the pre-signal intersection. The distance of the boundary line from the stop line is equal to the length of the comprehensive function area. The distance of the boundary line from the stop line is equal to 0, i.e., the boundary line coincides with the stop line. The specific expression is:

[0449] ;

[0450] ;

[0451] ;

[0452] ;

[0453] .

[0454] Each partition length has a minimum constraint, and the specific expression is:

[0455] .

[0456] ②The sub-intersection vehicle travel trajectory constraint includes:

[0457] ​​​​​​​The vehicle driving track at the pre-signal is simplified as two circular curves with opposite connection and same radius, the pre-signal length is determined by the minimum design speed at the pre-signal, and the specific expression is:

[0458]

[0459]

[0460] On the basis of the above constraints, the driving track length, driving speed and driving time of each connection path can be further determined, and the specific expression is:

[0461]

[0462]

[0463]

[0464]

[0465]

[0466]

[0467] At the main signal, each connection path can also be simplified as two circular curves with opposite connection and same radius, a straight line + a circular curve, or a straight line, and by referring to the calculation idea at the pre-signal, the relevant parameters of each connection path can be determined.

[0468] wherein, represents the buffer zone length in the direction represents the variable guide zone length in the direction represents the comprehensive function zone length in the direction represents the control zone length in the direction represents the pre-signal intersection length in the direction represents the distance of each sub-area boundary line in the direction from the stop line, represents the minimum value of the sub-area length of the corresponding sub-area. represents the minimum design radius at the pre-signal represents the minimum design radius at the main signal, represents the minimum design speed at the pre-signal in the direction represents the minimum design speed at the main signal,​​​​​​​​​​​​​​​​ Represents gravitational acceleration. This represents the road surface friction coefficient. Indicates the cross slope of the road surface. lane With lane The horizontal distance between them Indicates direction The length of the pre-signal intersection, Indicates from lane Drive to the lane Turning radius, Indicates the lane in the sub-intersection Enter the lane driving speed, Indicates the deflection angle of a circular curve. Indicates the lane in the sub-intersection Enter the lane Travel time. Indicates the lane in the sub-intersection Drive to the lane The length of the driving trajectory.

[0469] In this embodiment, optionally, solving the mixed-integer linear programming optimization model includes:

[0470] When a viable solution cannot be obtained by solving a mixed-integer linear programming optimization model, it is determined whether the number of planning steps meets the update condition.

[0471] In response to the satisfaction of the update condition, the number of planning steps is updated, and the mixed integer linear programming optimization model is solved again;

[0472] In response to the failure to meet the update conditions, update the number of steps in the planned vehicle list and reacquire the traffic state information of each vehicle arriving at the flexible intersection control area to solve the mixed integer linear programming optimization model.

[0473] Specifically, before solving the mixed-integer linear programming optimization model, we can first determine the number of steps in the planned vehicle list. The initialization formula for the number of planning steps is as follows:

[0474] .

[0475] Then, the mixed-integer linear programming optimization model is solved, and it is determined whether a viable solution can be obtained by solving the mixed-integer linear programming optimization model. If not, it is further determined whether the number of planning steps meets the update condition.

[0476] In this embodiment, the update condition can be set as follows: .

[0477] If the above update condition is satisfied, the planning step number can be updated according to the time step, and the mixed integer linear programming optimization model is re-solved, and the specific calculation formula of the updated planning step number is: , wherein, is the updated planning step number, is the maximum free-flow travel time for the vehicle to travel in different lanes from the entry control area to the final exit selection, represents the planning step number increase interval.

[0478] If the above update condition is not satisfied, the planning vehicle list step number can be planned, and the traffic information of all vehicles in the planning vehicle list is re-collected to re-solve the mixed integer linear programming optimization model. The specific calculation formula of the planning vehicle list step number update is: , is the updated planning vehicle list step number, represents the planning vehicle list step number increase interval.

[0479] This is repeated until the traffic plan can be obtained by solving the mixed integer linear programming optimization model, that is, the traffic plan of the next planning phase.

[0480] A computer program product comprising computer programs / instructions, which, when executed by a processor, implement the steps of the above traffic plan planning method.

[0481] The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application.

Claims

1. A method for planning a traffic plan at a flexible intersection, characterized by, The method comprises the following steps: acquiring traffic state information of each vehicle reaching a control area of a flexible intersection in a current planning stage; solving a mixed integer linear programming optimization model by using a standard branch and bound algorithm to obtain a passing scheme based on the traffic state information of all vehicles; the objective function of the mixed integer linear programming optimization model comprises a primary optimization target and three secondary optimization targets, the primary optimization target is to minimize a difference between an actual driving time and a free flow driving time, and the three secondary optimization targets are to minimize an absolute value of acceleration, to minimize a cycle length, and to minimize a number of lane changes of a vehicle, respectively, and the objective function of the mixed integer linear programming optimization model is specifically: ； wherein, is a direction, is a set of directions, is a vehicle flow direction, is a vehicle number, is a vehicle flow direction of a vehicle set, denotes a vehicle passing a direction midline at a corresponding time, is a vehicle passing a direction midline at a corresponding time, is a start time of trajectory optimization, is a recorded time when a vehicle first enters a control zone, is a flow direction from entering a control zone to finally leaving a control zone free-flow driving time, is a phase green light interval time between two adjacent phases, is a time step, is a set of time steps, is a vehicle acceleration at a time step, is a cycle length at a main signal, is a cycle length at a pre-signal in a direction , is a minimum comfortable acceleration allowed by a vehicle, is a maximum comfortable acceleration allowed by a vehicle, is a planning step number, is a lane number, is a set of lanes in a direction , is whether a vehicle is on a lane at a time step , , are priority coefficients corresponding to a first-level optimization target and a second-level optimization target, respectively; the flexible intersection is an intersection in which pre-signals are additionally arranged on road segments in each direction of the intersection, the flexible intersection adopts dynamic reversible lanes and is managed by lane level through road lane number marking and lane level signal lights, each direction adjusts a passing scheme of lane use function and driving direction switching between a main signal and a pre-signal, and the number of driving lanes in each flow direction is adjusted in real time; direction set west, south, east, and north, respectively; the minimum comfortable acceleration is a minimum acceleration that does not affect the comfort of passengers during vehicle driving; the maximum comfortable acceleration is a maximum acceleration that does not affect the comfort of passengers during vehicle driving; the priority coefficient is a priority weighting coefficient of different optimization targets; the constraint condition of the mixed integer linear programming optimization model comprises a lane division constraint, and the lane division constraint comprises: a buffer zone lane division constraint, a variable guide zone lane division constraint, a comprehensive function zone lane division constraint, a pre-signal intersection lane connection constraint, a main signal intersection lane connection constraint, and a constraint that only one passing design scheme is allowed in each direction, and upstream intersection design needs to be symmetrically arranged; the buffer zone lane division constraint comprises: each lane of the buffer zone is allowed to drive at least one vehicle flow; each vehicle flow in the buffer zone is allowed to drive at least one lane; left turn driving-in and straight driving-in in the buffer zone need to share a lane, and left turn driving-out and straight driving-out need to share a lane; driving-in vehicle flow and driving-out vehicle flow are not allowed to share a lane; the left turn driving-out and straight driving-out lane is located on the left side of the left turn driving-in and straight driving-in lane; and the buffer zone matching lane is set as a driving-in lane; The lane division constraint of the variable guidance zone comprises: at least one traffic flow is allowed to travel in each lane in the variable guidance zone; each traffic flow has at least one lane for traveling; the left-turn exit and the straight exit have the same lane marking in the variable guidance zone and the buffer zone; the left-turn entry and the straight entry have the same lane marking in the variable guidance zone and the buffer zone; in other design schemes except the parallel flow, the left-turn entry lane is located on the left side of the straight entry lane; if the parallel flow design is adopted, the straight entry lane is located on the left side of the left-turn entry lane; the lane connection constraint of the pre-signal intersection comprises: the number of approaching lanes of each flow direction is not greater than the number of receiving lanes; the approaching lanes and the receiving lanes can be connected only when they allow a certain traffic flow to be used at the same time; in other designs except the left-turn design by using a lane and the array design, the two connection paths of the left-turn entry cannot intersect; in other designs except the array design, the two connection paths of the straight entry cannot intersect; the two connection paths of the left-turn exit and the straight exit cannot intersect; in other designs except the left-turn design by using a lane and the array design, each approaching lane of the left-turn entry has only one connection path; in other designs except the array design, each approaching lane of the straight entry has only one connection path; each receiving lane of the left-turn entry and the straight entry has not more than one connection path; each approaching lane of the left-turn exit and the straight exit has only one connection path, and each receiving lane has not more than one connection path; each approaching lane has not less than one connection path; in the left-turn design by using a lane, the conventional left-turn lane in the comprehensive function zone must be connected with the same lane in the variable guidance zone; in the array design, if a certain entry lane in the comprehensive function zone is not a shared lane of the left-turn entry and the straight entry, the same lane in the variable guidance zone must be connected. The lane division constraint of the comprehensive function zone comprises: each lane allows at least one traffic flow to travel, and each traffic flow has at least one lane for traveling; the same lane marking of each flow direction in the comprehensive function zone and the variable guidance zone is the same.

2. The method of trip plan planning according to claim 1, wherein, The lane division constraint of the comprehensive function zone comprises special requirement constraint conditions corresponding to various traffic design schemes.

3. The method of trip plan planning according to claim 1, wherein, The constraint condition of the mixed integer linear programming optimization model comprises a trajectory planning constraint, and the trajectory planning constraint comprises: an acceleration variable domain constraint, a speed variable domain constraint, a position variable domain constraint, a sub-crossing connection path matching variable domain constraint, a lane selection variable domain constraint, and a following and lane-changing behavior safety constraint.

4. The traffic scenario planning method of claim 1, wherein, The constraint condition of the mixed integer linear programming optimization model comprises a signal timing constraint, and the signal timing constraint comprises: a main signal phase sequence constraint, a vehicle passing through a main signal stop line time constraint, a pre-signal phase sequence constraint, and a vehicle passing through a pre-signal stop line time constraint.

5. The method of trip plan planning according to claim 4, wherein, The pre-signal phase sequence constraint comprises special requirement constraint conditions corresponding to various traffic design schemes.

6. The transit scenario planning method of claim 1, wherein, The constraint condition of the mixed integer linear programming optimization model comprises a sub-zone division constraint, and the sub-zone division constraint comprises: a sub-zone length constraint and a sub-crossing vehicle travel trajectory constraint.

7. The method of trip plan planning according to claim 1, wherein, Solving the mixed integer linear programming optimization model comprises: When the traffic plan cannot be obtained by solving the mixed integer linear programming optimization model, it is determined whether the planning step number meets an update condition; In response to the update condition being met, the planning step number is updated, and the mixed integer linear programming optimization model is solved again; In response to the update condition not being met, the planning vehicle list step number is updated, and the traffic state information of each vehicle arriving at the flexible intersection control area is reacquired to solve the mixed integer linear programming optimization model.

8. A computer program product comprising computer programs / instructions, characterized in that, The computer program / instructions are executed by the processor to implement the steps of the traffic plan planning method according to any one of claims 1-7.

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