Disaster relief vehicle traffic optimization control method

Abstract

The application provides a post-disaster rescue vehicle traffic optimization regulation method, and belongs to the field of post-disaster road space-time resource allocation and integrated road traffic control. The technical scheme is as follows: a corresponding traffic optimization model one and a traffic optimization model two are established by taking the fastest arrival of the rescue vehicle at the accident position as the target, and the corresponding models are solved, and finally the traffic optimization scheme of the corresponding rescue vehicle on the road network is obtained. The beneficial effects of the application are as follows: the method can reduce the road scale occupied by the rescue vehicle to coordinate the daily traffic of social vehicles, reduce the adverse effects on the normal traffic of social vehicles under the condition of ensuring the rapid arrival of the rescue vehicle at the accident position.

Description

Technical Field

[0001] This invention relates to the field of post-disaster road spatiotemporal resource allocation and integrated road traffic control, and more particularly to a method for optimizing and controlling traffic for post-disaster relief vehicles. Background Technology

[0002] Following disasters such as building collapses and fires, the road network typically carries a large number of rescue vehicles heading to the accident site for emergency relief, as well as regular road traffic. However, road resources are limited, and the emergency passage of rescue vehicles on the road network can interfere with or even delay the daily passage of other vehicles. In this situation, if it is possible to ensure that rescue vehicles can reach the accident site quickly without delay, while also minimizing the road space occupied by rescue vehicles, then the passage of other vehicles can be coordinated when rescue vehicles have priority.

[0003] like Figure 1 The road network topology diagram shown depicts nodes and their numbers representing intersections and their numbers, with lines between nodes representing road segments. A rescue vehicle enters the network at intersection 11 and exits at intersection 1. r1, r2, and r3 are three feasible routes. If the rescue vehicle uses r1, it passes through two intersections (intersections 9 and 10) and three road segments. If both r2 and r3 are used, it passes through three intersections (intersections 8, 3, and 2), resulting in five road segments. If only one of r2 or r3 is used, it passes through three intersections (intersections 8, 3, and 2), resulting in only four road segments. Clearly, the number of road segments and intersections traversed varies depending on the route chosen by the rescue vehicle on the network. However, existing methods for optimizing traffic flow for rescue vehicles do not consider how to reduce the number of road segments and intersections that rescue vehicles pass through when enabling them to reach the accident site quickly. They also lack the ability to coordinate the use of road network resources by yielding vehicles and cannot support the efficient operation of multi-priority and multi-vehicle traffic on the road network after a disaster, including social vehicles and evacuation vehicles. Summary of the Invention

[0004] The purpose of this invention is to provide a method for optimizing and controlling traffic for disaster relief vehicles to overcome the shortcomings of existing technologies.

[0005] This invention is achieved through the following measures:

[0006] A method for optimizing and controlling traffic flow for disaster relief vehicles, characterized in that the method includes the following steps:

[0007] S1. To establish a traffic optimization model for rescue vehicles on the road network with the goal of getting rescue vehicles to the accident location as quickly as possible;

[0008] S2. Solve the traffic optimization model one to obtain the upper limit number of road segments, lower limit number of road segments, upper limit number of intersections, and lower limit number of intersections that allow rescue vehicles to pass.

[0009] S3. Based on the traffic optimization model one, establish a traffic optimization model two that considers the constraints on the number of road segments and intersections after a disaster. The constraints on the number of road segments and intersections refer to the restrictions on the number of road segments and intersections used by rescue vehicles.

[0010] S4. In the second traffic optimization model, adjust the number of road segments and intersections that rescue vehicles are allowed to pass through on the road network to obtain the corresponding traffic optimization scheme for rescue vehicles to pass through the road network. Specifically, adjust the values ​​of the number of road segments a and the number of intersections b. By obtaining and comparing the objective function values ​​of all rescue vehicle traffic optimization under the same number of rescue vehicles, the traffic optimization scheme for rescue vehicles to pass through the road network can be obtained.

[0011] The invention also has the following specific features:

[0012] The specific steps of S2 are as follows:

[0013] S21. Solve the traffic optimization model to obtain the optimal path for rescue vehicles to pass through the road network. The number of road segments A and the number of intersections B contained in the optimal path are respectively used as the upper limit of the number of road segments a and the number of intersections b that rescue vehicles are allowed to pass under the condition of the same number of rescue vehicles, that is, a≤A, b≤B. Specifically, the number of road segments A is used as the upper limit of the number of road segments a, and the number of intersections B is used as the upper limit of the number of intersections b.

[0014] S22. Solve the traffic optimization model one to obtain the shortest path that rescue vehicles can take through the road network. The number of road segments C and the number of intersections D contained in the shortest path are used as the lower limits of the number of road segments a and the number of intersections b that rescue vehicles are allowed to take under the condition that the number of rescue vehicles is the same, i.e., C≤a, D≤b. Specifically, the number of road segments C is used as the lower limit of the number of road segments a, and the number of intersections D is used as the lower limit of the number of intersections b. If the number of road segments C and the number of intersections D are different among multiple shortest paths, the number of road segments C and the number of intersections D contained in the shortest path containing the fewest intersections are taken as the lower limits of the number of road segments a and the number of intersections b that rescue vehicles are allowed to take under the same number of rescue vehicles.

[0015] It's important to note that, according to existing theory, an optimal path contains multiple paths, and not all paths are necessarily the shortest. The shortest path is the shortest path in the optimal path solution set; that is, the shortest path can be found among the optimal paths. The objective function used to solve for both the optimal and shortest paths is the same, but the constraints differ. Therefore, the optimal path refers to the maximum value of the objective function under the corresponding constraints of the optimal path, while the shortest path refers to the maximum value of the objective function under the corresponding constraints of the shortest path.

[0016] The traffic optimization model includes an objective function and corresponding constraints.

[0017] The objective function is:

[0018]

[0019] In the formula: parameter T represents the length of the time window in which the rescue vehicle travels on the road network; parameter t represents any time step within the time window in which the rescue vehicle travels on the road network, t = 1, 2, ..., T; set L1 represents the road segments connecting the road network to the accident location; set Represents the upstream adjacent road segment of road segment j; variable Decision on the number of rescue vehicles that travel from road segment i through road segment j to the accident location within the t-th time period;

[0020] The corresponding constraints are:

[0021]

[0022]

[0023]

[0024]

[0025] V i t -V i i-1 ≤Q i , t=1, 2,...,T; i∈L (6)

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035] In the formula: parameter l i The parameter τ represents the length of road segment i. i Indicates the travel time of a rescue vehicle on road segment i under free-flow traffic conditions; parameter ι i This represents the time required for a congestion wave to propagate from the downstream end to the upstream end of road segment i under traffic congestion conditions; parameter This represents the maximum number of rescue vehicles that road segment i can accommodate under traffic congestion conditions; parameter Q i The parameter R represents the maximum number of rescue vehicles that can pass through road segment i at any time step; the parameter R represents the number of rescue vehicles called from the rescue station; the set The set L1 represents the downstream adjacent road segment of road segment i; set L2 represents the road segment connecting the rescue station to the road network; variables Calculate the number of rescue vehicles on road segment i at the initial time step t; variables and V i t Calculate the cumulative number of rescue vehicles entering and leaving road segment i up to the end of time step t. Equation (2) represents the conservation equation for the number of rescue vehicles on each road segment; Equations (3) and (4) represent the final arrival of all rescue vehicles called from the rescue station at the accident location; Equations (5) to (8) simulate the dynamic loading process of rescue vehicles on the road network based on the road segment transmission model; Equations (9) and (10) calculate the cumulative number of rescue vehicles entering and leaving each road segment up to the end of any time step; Equation (11) represents the number of rescue vehicles entering and leaving each road segment due to the limitation of free-flow travel time on the road. Within a given time period, no rescue vehicles can leave the road segment they have entered; Equations (12) and (13) represent the initial rescue traffic state of the road; Equations (14) and (15) represent the non-negative constraints of the dynamic loading process of rescue vehicles on the road network. In addition, the cumulative number of rescue vehicles entering and leaving each road segment up to the non-integer time step involved in Equations (5) and (7) can be calculated based on the linear interpolation method of the corresponding values ​​at the integer time step.

[0036] Solving the traffic optimization model one yields the optimal path for rescue vehicles to travel on the road network. Specifically, this involves solving the traffic optimization model one for rescue vehicles in step S1, with equation (1) as the objective function and equations (2) to (15) as constraints.

[0037] The traffic optimization model 2 consists of the traffic optimization model 1 and new constraints;

[0038] The new constraint is:

[0039] ∑ z∈Z y z ≤b,D≤b≤B (16)

[0040]

[0041] ∑i∈Lgi≤a,C≤a≤A (18)

[0042]

[0043] In the formula: parameter M represents a sufficiently large positive number; set Z represents the intersection; 0-1 variable y z Decision z: Whether the vehicle being rescued is allowed to pass through intersection y z =1 indicates that it is allowed, y z =0 indicates not allowed; 0-1 variable g i Whether to allow the rescued vehicle to pass through section i, g i =1 indicates that it is allowed, g i =0 indicates that it is not allowed. Equations (16) to (19) indicate that the number of road segments and intersections that rescue vehicles are allowed to pass through shall not exceed a and b, respectively;

[0044] Based on the first traffic optimization model, the second traffic optimization model is established by adjusting the number of road segments a and the number of intersections b that the rescue vehicle passes through on the road network using equations (16) to (19).

[0045] The beneficial effects of this invention are: this method can reduce the road space occupied by rescue vehicles to coordinate the daily traffic of social vehicles, and reduce the adverse impact on the normal traffic of social vehicles while ensuring that rescue vehicles can quickly reach the accident site. Attached Figure Description

[0046] Figure 1 This is a diagram of the road network topology involved in the background technology.

[0047] Figure 2 This is a schematic diagram of Embodiment 2 of the present invention. Detailed Implementation

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0050] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0051] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0052] Example 1

[0053] A method for optimizing and controlling traffic flow for disaster relief vehicles, the method comprising the following steps:

[0054] S1. To establish a traffic optimization model for rescue vehicles on the road network with the goal of getting rescue vehicles to the accident location as quickly as possible;

[0055] S2. Solve the traffic optimization model to obtain the optimal path for the rescue vehicle to pass through the road network;

[0056] S3. The number of road segments A and the number of intersections B contained in the optimal path are respectively used as the upper limit of the number of road segments a and the number of intersections b that rescue vehicles are allowed to pass under the condition of the same number of rescue vehicles, that is, a≤A, b≤B. Specifically, the number of road segments A is used as the upper limit of the number of road segments a, and the number of intersections B is used as the upper limit of the number of intersections b.

[0057] S4. Solve the traffic optimization model one to obtain the shortest path that rescue vehicles can take through the road network. The number of road segments C and the number of intersections D contained in the shortest path are used as the lower limits of the number of road segments a and the number of intersections b that rescue vehicles are allowed to take under the condition that the number of rescue vehicles is the same, i.e., C≤a, D≤b. Specifically, the number of road segments C is used as the lower limit of the number of road segments a, and the number of intersections D is used as the lower limit of the number of intersections b. If the number of road segments C and the number of intersections D are different among multiple shortest paths, the number of road segments C and the number of intersections D contained in the shortest path containing the fewest intersections are taken as the lower limits of the number of road segments a and the number of intersections b that rescue vehicles are allowed to take under the same number of rescue vehicles.

[0058] S5. With the goal of enabling rescue vehicles to reach the accident location as quickly as possible, establish a second traffic optimization model that considers the constraints on the number of road segments and intersections after the disaster. The constraints on the number of road segments and intersections refer to the restrictions on the number of road segments and intersections used by rescue vehicles.

[0059] S6. In the second traffic optimization model, adjust the number of road segments a and the number of intersections b that allow rescue vehicles to pass through the road network, and obtain the corresponding traffic optimization scheme for rescue vehicles to pass through the road network. Specifically, adjust the values ​​of the number of road segments a and the number of intersections b, and obtain and compare the objective function values ​​of all rescue vehicle traffic optimization under the same number of rescue vehicles, thereby obtaining the traffic optimization scheme for rescue vehicles to pass through the road network.

[0060] The traffic optimization model includes an objective function and corresponding constraints.

[0061] The objective function is:

[0062]

[0063] In the formula: parameter T represents the length of the time window in which the rescue vehicle travels on the road network; parameter t represents any time step within the time window in which the rescue vehicle travels on the road network, t = 1, 2, ..., T; set L1 represents the road segments connecting the road network to the accident location; set Represents the upstream adjacent road segment of road segment j; variable Decision on the number of rescue vehicles that travel from road segment i through road segment j to the accident location within the t-th time period;

[0064] The corresponding constraints are:

[0065]

[0066]

[0067]

[0068]

[0069] V i t -V i t-1 ≤Q i , t=1,2…,T;i∈L (6)

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] In the formula: parameter l i The parameter τ represents the length of road segment i. i Indicates the travel time of a rescue vehicle on road segment i under free-flow traffic conditions; parameter ι i This represents the time required for a congestion wave to propagate from the downstream end to the upstream end of road segment i under traffic congestion conditions; parameter This represents the maximum number of rescue vehicles that road segment i can accommodate under traffic congestion conditions; parameter Q i The parameter R represents the maximum number of rescue vehicles that can pass through road segment i at any time step; the parameter R represents the number of rescue vehicles called from the rescue station; the set The set L1 represents the downstream adjacent road segment of road segment i; set L2 represents the road segment connecting the rescue station to the road network; variables Calculate the number of rescue vehicles on road segment i at the initial time step t; variables and V i tCalculate the cumulative number of rescue vehicles entering and leaving road segment i up to the end of time step t. Equation (2) represents the conservation equation for the number of rescue vehicles on each road segment; Equations (3) and (4) represent the final arrival of all rescue vehicles called from the rescue station at the accident location; Equations (5) to (8) simulate the dynamic loading process of rescue vehicles on the road network based on the road segment transmission model; Equations (9) and (10) calculate the cumulative number of rescue vehicles entering and leaving each road segment up to the end of any time step; Equation (11) represents the number of rescue vehicles entering and leaving each road segment due to the limitation of free-flow travel time on the road. Within a given time period, no rescue vehicles can leave the road segment they have entered; Equations (12) and (13) represent the initial rescue traffic state of the road; Equations (14) and (15) represent the non-negative constraints of the dynamic loading process of rescue vehicles on the road network. In addition, the cumulative number of rescue vehicles entering and leaving each road segment up to the non-integer time step involved in Equations (5) and (7) can be calculated based on the linear interpolation method of the corresponding values ​​at the integer time step.

[0080] Solving the traffic optimization model one yields the optimal path for rescue vehicles to travel on the road network. Specifically, this involves solving the traffic optimization model one for rescue vehicles in step S1, with equation (1) as the objective function and equations (2) to (15) as constraints.

[0081] The traffic optimization model 2 consists of the traffic optimization model 1 and new constraints;

[0082] The new constraint is:

[0083] ∑ z∈Z y z ≤b,D≤b≤B (16)

[0084]

[0085] ∑ i∈L g i ≤a,C≤a≤A (18)

[0086]

[0087] In the formula: parameter M represents a sufficiently large positive number; set Z represents the intersection; 0-1 variable y z Decision z: Whether the vehicle being rescued is allowed to pass through intersection y z =1 indicates that it is allowed, y z =0 indicates not allowed; 0-1 variable g i Whether to allow the rescued vehicle to pass through section i, g i =1 indicates that it is allowed, g i =0 indicates that it is not allowed. Equations (16) to (19) indicate that the number of road segments and intersections that rescue vehicles are allowed to pass through shall not exceed a and b, respectively;

[0088] Based on the first traffic optimization model, the second traffic optimization model is established by adjusting the number of road segments a and the number of intersections b that the rescue vehicle passes through on the road network using equations (16) to (19).

[0089] Example 2

[0090] See Figure 2 This embodiment is based on Embodiment 1 and is implemented through the following process:

[0091] Step 1: For any number R of rescue vehicles called after the disaster, input them as known parameters into the traffic optimization model 1, which is constrained by maxf according to equations (2) to (15). Solve the traffic optimization model 1 to obtain the optimal path for the rescue vehicles to pass through the road network. The number of road segments A and the number of intersections B contained in the optimal path are respectively used as the upper limit of the number of road segments a and the number of intersections b that the rescue vehicles pass through on the road network when the number of rescue vehicles is R.

[0092] Step 2: Adjust the number of road segments 'a' and the number of intersections 'b' that rescue vehicles are allowed to pass through on the road network after the disaster in increments of 1, and compare them with the lower limit values ​​of the number of road segments 'C' and the number of intersections 'D': if a≥C and b≥D are true, proceed to Step 3; otherwise, return to Step 1.

[0093] Step 3: Input the parameter values ​​R from Step 1 and a and b from Step 2 into the second traffic optimization model, which is constrained by maxf according to equations (2) to (19) and considers the constraints on the number of road segments and intersections traversed by rescue vehicles. Solve the second traffic optimization model to obtain the corresponding traffic optimization scheme for the rescue vehicles to travel on the road network. Return to Step 2 to continue solving.

[0094] Step 4: After solving the problem, compare the objective function values ​​of all rescue vehicle traffic optimization under the same R, and obtain the final traffic optimization scheme for rescue vehicles to travel on the road network.

[0095] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A method for optimizing and controlling traffic flow for disaster relief vehicles, characterized in that, The control method includes the following steps: S1. To establish a traffic optimization model for rescue vehicles on the road network with the goal of getting rescue vehicles to the accident location as quickly as possible; S2. Solve the traffic optimization model one to obtain the upper limit number of road segments, lower limit number of road segments, upper limit number of intersections, and lower limit number of intersections that allow rescue vehicles to pass. Specific steps include: S21. Solve the traffic optimization model to obtain the optimal route for rescue vehicles to pass through the road network. The number of road segments A and intersections B included in the optimal route are used as the upper limits for the number of road segments a and intersections b allowed for rescue vehicles to pass through, respectively, under the condition of the same number of rescue vehicles. , ; S22. Solve the traffic optimization model one to obtain the shortest path for rescue vehicles on the road network. Use the number of road segments C and intersections D included in the shortest path as the lower limits for the number of road segments a and intersections b that rescue vehicles are allowed to pass through under the condition of the same number of rescue vehicles. , ; S3. Based on the traffic optimization model one, establish a traffic optimization model two that considers the constraints on the number of road segments and intersections after the disaster. The traffic optimization model two consists of the traffic optimization model one and the new constraints. S4. In the second traffic optimization model, adjust the number of road segments and intersections that allow rescue vehicles to pass through the road network, and obtain the corresponding traffic optimization scheme for rescue vehicles to pass through the road network.

2. The method for optimizing and controlling traffic for disaster relief vehicles according to claim 1, characterized in that, The traffic optimization model includes an objective function and corresponding constraints.

Images