A multi-dimensional control method for bottleneck area mixed traffic based on CAV cooperation

Abstract

The application discloses a kind of bottleneck zone mixed traffic multidimensional control method based on CAV cooperation, belong to intelligent network connection traffic control field.The application selects lane-controlled speed CAV, lane-controlled distance CAV on the upstream of bottleneck to form cooperative control pair, controls the arrival rate of vehicle on the upstream of bottleneck by calculating the expected speed of lane-controlled speed CAV;Desired acceleration of lane-controlled distance CAV is solved based on improved intelligent driver model, and mobile safety lane-changing window is constructed by matching customized expected inter-vehicle distance formula.The application sets multiple event trigger conditions to dynamically update cooperative vehicles, adds traffic density monitoring anti-flow interruption mechanism, and designs adaptive strategies for single lane, no CAV and other special conditions.The application passively guides artificial vehicle lane-changing through the driving state of network-connected vehicle, without the active cooperation of driver, balances the distribution of bottleneck traffic flow from time and space dimensions, effectively suppresses the congestion caused by concentrated lane-changing, and significantly improves the road traffic efficiency, driving safety and scheme working condition robustness in mixed traffic scenarios.

Description

Technical Field

[0001] This invention belongs to the fields of cyber-physical systems, intelligent transportation systems and autonomous driving control technology, and specifically relates to a multi-dimensional control method for bottleneck area mixed traffic based on CAVs collaboration. Background Technology

[0002] Bottleneck areas such as lane reduction zones and merging zones are prone to congestion due to traffic overload and concentrated demand for forced lane changes. Congestion often leads to a decrease in capacity, meaning the release rate of vehicles queuing in the bottleneck area is lower than the maximum traffic capacity, significantly negatively impacting traffic safety and efficiency. Therefore, it is necessary to control traffic flow in bottleneck areas, guiding it into lane reduction zones in an organized manner to avoid traffic overload and concentrated demand for forced lane changes, thus preventing congestion.

[0003] Existing control research mainly revolves around two methods: Variable Speed ​​Limit (VSL) and Lane Change (LC). VSL regulates traffic flow by limiting the speed of upstream vehicles, thus delaying their arrival time. Based on control granularity, VSL can be divided into road-level and lane-level. Road-level VSL applies a uniform speed limit across the entire road segment, while lane-level VSL sets dynamically differentiated speed limits for each lane to more precisely consider the impact of lane-changing behavior. Although both can delay traffic flow in the time dimension, they both have limitations: road-level VSL cannot optimize lane distribution, while lane-level VSL may actually increase the difficulty of lane changes due to speed differences between lanes. Therefore, both methods can still easily lead to a buildup of forced lane-changing demand at lane reduction points, limiting their control effectiveness. Furthermore, VSL is usually implemented through variable message signs, and its effectiveness is highly dependent on driver compliance; behavioral uncertainty can easily lead to control instability or even negative effects. LC optimizes lane distribution by inducing or controlling vehicles to change lanes in advance. However, in mixed traffic flows where human-driven vehicles (HDVs) and connected and automated vehicles (CAVs) coexist, especially under high-density congestion, lane-changing space is extremely limited. Even if lane-changing space is created through the cooperation of CAVs, it is easily encroached upon or interfered with by HDVs with random behavior, making it difficult for lane-changing guidance or control to be effective and stable. Forced lane-changing demand is still likely to accumulate at lane reduction points.

[0004] Therefore, there is an urgent need for a control method that fully utilizes the advantages of information interaction and motion coordination among CAVs, can simultaneously achieve traffic flow regulation in the time dimension and lane distribution optimization in the spatial dimension, is independent of driver compliance, and can still be stably executed and effectively alleviate congestion in high-density scenarios. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a multi-dimensional control method for mixed traffic in bottleneck areas based on CAV collaboration, which aims to achieve spatiotemporal multi-dimensional joint management and control by utilizing the collaboration of two-vehicle CAVs, and to solve the problems of traditional control methods relying on driver cooperation, insufficient lane-changing space in high-density scenarios, and the inability to synchronously optimize traffic flow and lane distribution.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A multi-dimensional control method for mixed traffic in bottleneck areas based on CAVs collaboration includes the following steps:

[0008] S1. Cooperative selection and pairing of controlled CAVs: Two connected autonomous driving vehicles (CAVs) belonging to different lanes are selected in the upstream control area of ​​the bottleneck area to form a cooperative control pair, namely the speed-controlling CAV and the distance-controlling CAV.

[0009] The selection rules for the speed-controlled CAV are as follows: the leading CAV is located in a non-passable lane or conflict lane, and the longitudinal distance from the end of the lane change guidance area is greater than the preset boundary margin threshold. When there are multiple candidates, the first CAV in the longitudinal position is selected.

[0010] The selection rules for the distance control CAV are as follows: it is located in another lane different from the speed control CAV, and is located behind the speed control CAV. The longitudinal distance between it and the speed control CAV is greater than the preset safe lane-changing window length. When there are multiple candidates, the first CAV in the longitudinal position is selected.

[0011] During the control cycle, speed-controlled CAVs and distance-controlled CAVs are prohibited from performing lane-changing operations.

[0012] S2. Speed ​​control of speed-controlled CAV: Implement speed control for speed-controlled CAVs and dynamically adjust their target speed to control the vehicle arrival rate on impassable lanes;

[0013] S3. Longitudinal spacing control of distance-controlled CAV: The distance-controlled CAV uses the motion state of the speed-controlled CAV as a reference benchmark, calculates its own desired acceleration based on the improved intelligent driver model, and adjusts the acceleration to maintain a stable longitudinal spacing between the two vehicles, thus creating a moving safety window that allows vehicles behind to change lanes in advance.

[0014] S4. Dynamic updates of controlled CAVs based on event triggers;

[0015] The status of speed control CAV and distance control CAV is monitored in real time. When any of the following trigger conditions are met, the control of the current cooperative control pair is terminated, and the process returns to step S1 to select a new cooperative control pair:

[0016] Position trigger: The distance between the speed control CAV and the end of the lane change guidance zone is less than the preset threshold;

[0017] Lane Trigger: The lane currently occupied by the speed-controlled CAV is no longer a prohibited or conflicting lane;

[0018] Relative sequence triggering: The longitudinal position of the distance control CAV exceeds that of the speed control CAV;

[0019] S5. Anti-interruption mechanism;

[0020] Average density of the section from the location of the speed-controlled vehicle (CAV) to the entrance of the lane reduction zone. ,like , If the preset flow interruption density threshold is reached, it is determined that there is a risk of flow interruption, and all control over the speed control CAV and distance control CAV is immediately released to restore the vehicle's free movement.

[0021] S6. Special operating condition handling;

[0022] If there is only a CAV in a single lane within the lane change guidance zone, then the speed control strategy of step S2 is only executed for the leading CAV in that lane; if there are no CAVs in any lane within the lane change guidance zone, then no cooperative control is executed.

[0023] Furthermore, in step S2, the calculation expression for the target speed of the speed-controlled CAV, i.e., the desired speed, is:

[0024]

[0025] In the formula, This represents the current k-th control moment, with units of discrete speed control cycles. ; Indicates the current number At each control moment, the desired speed of the speed-controlled CAV; This indicates the historical expected speed of the speed control CAV in the previous control cycle; The initial desired speed is calculated based on proportional control. This is the proportionality coefficient; Indicates the current number Traffic flow density deviation at each control time; , They are respectively The upper and lower limits of the desired speed of the CAV (Continuous Actuation Vehicle) at all times; for The speed of the CAV is constantly controlled; The minimum decision value for the desired speed; The maximum expected speed change for speed-controlled CAVs; This indicates the free-flow velocity of that road section.

[0026] Furthermore, in step S3, the desired acceleration of the distance-controlled CAV is calculated based on an improved intelligent driver model:

[0027]

[0028] In the formula, for The desired acceleration of the time-controlled distance CAV; This represents the maximum acceleration of the CAV. for The speed of the CAV is constantly controlled; for The actual distance between the time-controlled distance CAV and the speed-controlled distance CAV; For speed control CAV acceleration weights, ; for Constant-time speed control of CAV acceleration; for The expected vehicle spacing between time-controlled CAV and speed-controlled CAV;

[0029]

[0030] In the formula, For stationary safe vehicle spacing; for The speed of the CAV is constantly controlled; Decelerate for comfort; Indicates the maximum vehicle length allowed to travel on this road segment; This indicates an additional safety margin for lane changes. .

[0031] Beneficial effects:

[0032] 1. Dual CAVs collaborative control enables multi-dimensional spatiotemporal joint regulation, resulting in significant control gain;

[0033] This invention selects only two CAVs belonging to different lanes to form a collaborative control pair, which respectively realize speed control and distance control functions, and work together to complete the regulation of bottleneck inflow in the time dimension and the active construction of moving lane-changing windows in the spatial dimension. Compared with single-vehicle control and multi-vehicle cluster control schemes, it significantly reduces the control calculation and communication costs, achieves a collaborative control effect of "1+1>2", and simultaneously solves the two core bottleneck problems of traffic overload and centralized forced lane changing.

[0034] 2. It does not rely on human driver compliance and has high control stability;

[0035] Traditional variable speed limit (VSL) systems rely on roadside information boards to issue instructions, and their control effectiveness depends entirely on the degree of driver cooperation. This invention directly physically constrains the driving status of vehicle-mounted vehicles (CAVs) and passively guides surrounding high-speed vehicles (HDVs) using the traffic flow barriers and lane-changing windows formed by the CAVs. This eliminates the control failures and traffic disturbances caused by random human behavior at the source, without requiring active driver response.

[0036] 3. Adapts to high-density, congested, mixed traffic scenarios, solving the problem of insufficient lane-changing space;

[0037] Under high-density traffic flow, the available gaps for lane changing are extremely limited. Traditional lane-changing guidance strategies are easily interfered with by randomly moving HDVs (High-Density Vehicles) and encroach on lane-changing space. This invention maintains a fixed safe lane-changing window length through dual CAV (Carrier-Action Vehicle) collaboration, continuously generating stable and controllable lane-changing space. This ensures that the early lane-changing guidance strategy can be stably implemented under high-density conditions, avoiding the accumulation of lane-changing demand at bottleneck sections.

[0038] 4. Multiple protection mechanisms ensure robustness and adaptability to various operating conditions;

[0039] ① Set up an event-triggered dynamic update mechanism to automatically switch collaborative control pairs based on vehicle location, lane, and relative order to adapt to dynamic changes in traffic flow;

[0040] ② A supporting anti-traffic interruption mechanism is implemented to monitor traffic density on road sections in real time, predict and remove control states that are prone to traffic interruption, and prevent a precipitous drop in bottleneck traffic efficiency.

[0041] ③ Add special working condition processing logic. Speed ​​control can still be executed independently in scenarios with low CAV penetration rate and single lane with CAV, and has complete working condition coverage capability.

[0042] 5. Balancing traffic efficiency with driving safety and passenger comfort;

[0043] The speed control mechanism incorporates upper and lower speed limits and limits on the maximum speed change range, and sets up anti-integral saturation logic to avoid traffic turbulence caused by drastic speed fluctuations. Standardized safe lane-changing windows can reduce dangerous lane-changing behaviors such as close-range cutting and sudden acceleration and deceleration, reduce the risk of conflict, and simultaneously improve road capacity, driving safety, and driving comfort.

[0044] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0045] Figure 1This is a schematic diagram of a multi-dimensional control scenario with dual CAVs working together, as shown in the embodiment.

[0046] Figure 2 To prevent power outages. Detailed Implementation

[0047] To make the technical solutions, advantages, and objectives of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the protection scope of this application.

[0048] Figure 1 Taking the lane reduction zone as an example, a schematic diagram of a multi-dimensional control scenario based on the coordinated cooperation of two CAVs is shown. The scenario is a 3km two-lane highway with a speed limit of 100km / h and a lane reduction zone. The lane reduction zone reduces two lanes to one lane, and the length of the control zone is 500m.

[0049] Figure 2 The process of the anti-traffic disruption mechanism is demonstrated. When an uncontrolled vehicle reaches the safe lane-changing window, if it chooses not to change lanes and continues to follow the car at a controlled speed (CAV), it can easily cause traffic disruption. In this situation, the anti-traffic disruption mechanism can promptly release control of the controlled CAVs, restoring normal traffic flow and thus preventing traffic disruption.

[0050] This embodiment uses Figure 1 Taking the scenario shown as an example, a multi-dimensional control method for mixed traffic in bottleneck areas based on CAVs collaboration is proposed, which specifically includes the following steps:

[0051] S1. Cooperative selection and pairing of controlled CAVs;

[0052] In the non-passable lane (right lane) of the lane change guidance zone, the foremost CAV (Carrier Aided Vehicle) with a distance greater than a preset boundary margin threshold (20m in this embodiment) from the lane reduction zone entrance is selected as the speed control CAV. In the left lane, the CAV located behind the speed control CAV, with a longitudinal distance greater than a preset safe lane change window length (15m in this embodiment) and the smallest distance, is selected as the distance control CAV. The speed control CAV and distance control CAV selected in this embodiment are as follows: Figure 1 As shown, the two constitute a coordinated control pair in the current control cycle and prohibit lane changing.

[0053] S2. Speed ​​control of CAV;

[0054] Speed ​​control is implemented on speed-controlled CAVs, and their target speed is dynamically adjusted to control the arrival rate of vehicles on impassable lanes, thereby regulating the inflow of traffic into lane reduction zones in the time dimension.

[0055] Specifically, let the speed control period be... Based on proportional control, according to the first indivual Internal speed control (CAV) expected speed , Traffic flow density in lane change guidance area at any time is Determine the first indivual Internal speed control (CAV) expected speed :

[0056]

[0057] In the formula, Indicates the current number Traffic flow density deviation at each control time; This is the proportionality coefficient;

[0058] To ensure driving safety, It should not exceed the maximum speed limit of the road section. Meanwhile, to prevent excessive speed limit changes and integral saturation, which could cause traffic instability and affect traffic safety and comfort, output limiting and anti-integral saturation measures are implemented. The final calculation formula:

[0059]

[0060] In the formula, This represents the current k-th control moment, with units of discrete speed control cycles. ; Indicates the current number At each control moment, the desired speed of the speed-controlled CAV; This indicates the historical expected speed of the speed control CAV in the previous control cycle; The initial desired speed is calculated based on proportional control. , They are respectively The upper and lower limits of the desired speed of the CAV (Continuous Actuation Vehicle) at all times; for The speed of the CAV is constantly controlled; The minimum decision value for the desired speed; The maximum expected speed change for speed-controlled CAVs; This indicates the free-flow velocity of that road section.

[0061] S3. Longitudinal spacing control of CAV;

[0062] When performing longitudinal spacing coordinated control, the distance control CAV uses the motion state of the speed control CAV in S2 as a reference benchmark. By actively adjusting the acceleration of the vehicle, it keeps the longitudinal spacing between itself and the speed control CAV at the preset safe lane-changing window length, thereby forming a stable and safe space window between the speed control CAV and the distance control CAV for vehicles behind to use when changing lanes.

[0063] In step S3, the desired acceleration of the distance-controlled CAV is calculated based on the improved intelligent driver model:

[0064]

[0065] In the formula, for The expected acceleration of the time-controlled distance CAV is a decision variable; This represents the maximum acceleration of the CAV. for The speed of the CAV is constantly controlled; for The actual distance between the time-controlled distance CAV and the speed-controlled distance CAV; For speed control CAV, the acceleration weights are determined because the vehicle spacing and speed difference should be the main factors in the acceleration decision. ; for Constant-time speed control of CAV acceleration; for The expected vehicle spacing between time-controlled CAV and speed-controlled CAV;

[0066]

[0067] In the formula, For stationary safe vehicle spacing; for The speed of the CAV is constantly controlled; Decelerate for comfort; Indicates the maximum vehicle length allowed to travel on this road segment; This indicates an additional safety margin for lane changes. Its value needs to be adjusted based on the experiment.

[0068] S4. Event-triggered update;

[0069] When the speed-controlled CAV moves to within 20 meters of the lane reduction zone entrance, the position trigger condition is met. The system terminates control of the currently controlled CAV and re-executes step S1 to select a new controlled CAV. The new speed-controlled CAV may be the nearest CAV behind that is located in a non-passing lane.

[0070] S5. Anti-interruption mechanism;

[0071] Anti-interruption mechanism such as Figure 2 As shown, every control cycle (set to 5 seconds in this embodiment), the average density from the location of the speed-controlled CAV to the entrance of the lane reduction zone is detected. .like < (Set to 0.02veh / m in this embodiment), if a flow interruption risk is detected, control over the controlled CAVs is immediately released, allowing the speed-controlled CAVs and distance-controlled CAVs to resume free movement, thus ensuring continuous flow input in the lane reduction zone. Figure 1 In the control scenario shown > Therefore, normal control is performed, and control is not released.

[0072] S6. Special operating condition handling;

[0073] In this embodiment, both lanes in the control area have CAVs, so multi-dimensional control is executed normally.

[0074] Therefore, by following the detailed steps outlined above, you can obtain... Figure 1 The illustrated embodiment uses a speed-controlled CAV and its desired speed, and a distance-controlled CAV and its desired acceleration. Speed ​​control of the speed-controlled CAV dynamically adjusts the inflow flow into the lane reduction zone; longitudinal spacing control of the distance-controlled CAV maintains a preset safe lane-changing window length with the speed-controlled CAV, actively constructing a stable space for following vehicles to change lanes; the controlled CAVs are dynamically updated based on an event-triggered mechanism; and an anti-flow interruption mechanism is set up to prevent flow interruption due to lane-changing guidance failure. Only two CAVs need to be controlled to simultaneously achieve flow regulation in the time dimension and lane distribution optimization in the spatial dimension, without relying on human driver compliance, and can still perform stably in high-density traffic flow scenarios.

[0075] It is hereby declared that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-dimensional control method for mixed traffic in bottleneck areas based on CAVs collaboration, characterized in that, Includes the following steps: S1. Cooperative selection and pairing of controlled CAVs: Two connected autonomous driving vehicles (CAVs) belonging to different lanes are selected in the upstream control area of ​​the bottleneck area to form a cooperative control pair, namely the speed-controlling CAV and the distance-controlling CAV. The selection rules for the speed-controlled CAV are as follows: the leading CAV is located in a non-passable lane or conflict lane, and the longitudinal distance from the end of the lane change guidance area is greater than the preset boundary margin threshold. When there are multiple candidates, the first CAV in the longitudinal position is selected. The selection rules for the distance control CAV are as follows: it is located in another lane different from the speed control CAV, and is located behind the speed control CAV. The longitudinal distance between it and the speed control CAV is greater than the preset safe lane-changing window length. When there are multiple candidates, the first CAV in the longitudinal position is selected. During the control cycle, speed-controlled CAVs and distance-controlled CAVs are prohibited from performing lane-changing operations. S2. Speed ​​control of speed-controlled CAV: Implement speed control for speed-controlled CAVs and dynamically adjust their target speed to control the vehicle arrival rate on impassable lanes; S3. Longitudinal spacing control of distance-controlled CAV: The distance-controlled CAV uses the motion state of the speed-controlled CAV as a reference benchmark, calculates its own desired acceleration based on the improved intelligent driver model, and adjusts the acceleration to maintain a stable longitudinal spacing between the two vehicles, thus creating a moving safety window that allows vehicles behind to change lanes in advance. S4. Dynamic updates of controlled CAVs based on event triggers; The status of speed control CAV and distance control CAV is monitored in real time. When any of the following trigger conditions are met, the control of the current cooperative control pair is terminated, and the process returns to step S1 to select a new cooperative control pair: Position trigger: The distance between the speed control CAV and the end of the lane change guidance zone is less than the preset threshold; Lane Trigger: The lane currently occupied by the speed-controlled CAV is no longer a prohibited or conflicting lane; Relative sequence triggering: The longitudinal position of the distance control CAV exceeds that of the speed control CAV; S5. Anti-interruption mechanism; Average density of the section from the location of the speed-controlled vehicle (CAV) to the entrance of the lane reduction zone. ,like , If the preset flow interruption density threshold is reached, it is determined that there is a risk of flow interruption, and all control over the speed control CAV and distance control CAV is immediately released to restore the vehicle's free movement. S6. Special operating condition handling; If there is only a CAV in a single lane within the lane change guidance zone, then the speed control strategy of step S2 is only executed for the leading CAV in that lane; if there are no CAVs in any lane within the lane change guidance zone, then no cooperative control is executed.

2. The multi-dimensional control method for mixed traffic in bottleneck areas based on CAVs collaboration according to claim 1, characterized in that, In step S2, the target speed of the speed-controlled CAV, i.e., the desired speed, is calculated as follows: In the formula, This represents the current k-th control moment, with units of discrete speed control cycles. ; Indicates the current number At each control moment, the desired speed of the speed-controlled CAV; This indicates the historical expected speed of the speed control CAV in the previous control cycle; The initial desired speed is calculated based on proportional control. This is the proportionality coefficient; Indicates the current number Traffic flow density deviation at each control time; , They are respectively The upper and lower limits of the desired speed of the CAV (Continuous Actuation Vehicle) at all times; for The speed of the CAV is constantly controlled; The minimum decision value for the desired speed; The maximum expected speed change for speed-controlled CAVs; This indicates the free-flow velocity of that road section.

3. The multi-dimensional control method for mixed traffic in bottleneck areas based on CAVs collaboration according to claim 2, characterized in that, In step S3, the desired acceleration of the distance-controlled CAV is calculated based on an improved intelligent driver model: In the formula, for The desired acceleration of the time-controlled distance CAV; This represents the maximum acceleration of the CAV. for The speed of the CAV is constantly controlled; for The actual distance between the time-controlled distance CAV and the speed-controlled distance CAV; For speed control CAV acceleration weights, ; for Constant-time speed control of CAV acceleration; for The expected vehicle spacing between time-controlled CAV and speed-controlled CAV; In the formula, For stationary safe vehicle spacing; for The speed of the CAV is constantly controlled; Decelerate for comfort; Indicates the maximum vehicle length allowed to travel on this road segment; This indicates an additional safety margin for lane changes. .

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