An intersection signal control method based on real-time spill detection

Abstract

The application discloses a kind of intersection signal control methods based on real-time overflow detection, it is related to intelligent transportation technology field, according to intersection real-time detection data, the overflow state of each flow direction of intersection is determined, and the mapping relationship between overflow state and passable traffic flow is established;Real-time light state of downstream intersection is obtained, the time required for overflow dissipation of current intersection is calculated;Based on the real-time queuing length of each direction of current intersection and signal light state, the expected traffic benefit under different signal control strategies is calculated, and a penalty mechanism for overflow deterioration is introduced;Combined with the business constraints of signal control, an optimization model is constructed to maximize the traffic capacity without worsening the overflow;Optimal control strategy is executed, and the optimal control strategy and optimal extension time are obtained by solving the optimization model, and are converted into signal machine control instructions to issue and execute.

Description

Technical Field

[0001] This invention relates to the field of intelligent transportation technology, and specifically to a method for intersection signal control based on real-time overflow detection. Background Technology

[0002] With the increase in the number of motor vehicles, intersections, as bottleneck nodes of the road network, are prone to overflow during peak hours. Overflow not only leads to deadlock at intersections, but also seriously reduces the traffic efficiency of the road network and causes secondary accidents. Existing signal control technologies (such as timing, sensing and traditional adaptive control) have significant defects in dealing with overflow problems: (1) Response lag: Traditional adaptive systems are usually optimized on a minute-level cycle, making it difficult to capture and deal with the "overflow" state that occurs on a second-level cycle. (2) Lack of coordination: When overflow occurs, the existing control logic may not fully consider the real-time release status of downstream intersections, making it difficult to achieve effective coordinated control of "upstream interception" or "downstream diversion", resulting in the overflow state not being alleviated in time. (3) Control target deviation: Existing algorithms mostly aim to minimize delay, but this target often fails in the overflow critical state, lacking a specific control strategy to prevent deadlock. Therefore, there is an urgent need for a new technical solution that can use advanced detection equipment (such as radar and electronic police) to accurately identify overflow states (including impending overflow, overflow, and overflow stop states) in real time, and combine the light status of upstream and downstream intersections to make timely and effective adjustments to the current signal phase in order to prevent overflow from worsening and ensure the normal operation of the intersection. Summary of the Invention

[0003] To overcome the shortcomings of the above technologies, this invention provides a method for effectively preventing and mitigating traffic overflow, avoiding intersection deadlock, and improving the traffic efficiency and reliability of urban road networks by real-time sensing of the overflow status of intersections and timely and dynamically adjusting the green light duration of the current signal phase.

[0004] The technical solution adopted by this invention to overcome its technical problems is: A method for controlling intersection signals based on real-time overflow detection, comprising: S1. Obtain the mapping relationship between the current overflow status of the intersection and the passable traffic flow based on the real-time detection data of the intersection; S2. Obtain the real-time traffic light status of the downstream intersections of the current intersection and calculate the remaining time for the overflow to dissipate at the current intersection. ; S3. Calculate the benefit functions under different signal control strategies based on the current signal control strategy and mapping relationship of the intersection. ; S4. Calculate the penalty term for the overflow state deteriorating into an overflow stop state. ; S5. Utilizing the benefit function and penalties Construct a signal control optimization model; S6. Based on the signal control optimization model, obtain the optimal decision variables and optimal extension time, convert the control strategy corresponding to the optimal decision variables and the optimal extension time into signal control commands and send them to the signal controller.

[0005] Furthermore, in step S1, the first The first import channel The mapping relationship between traffic flow turning is as follows: ,when Time indicates the first The first import channel Traffic flow turning into a single flow is feasible, when Time indicates the first The first import channel Traffic flow that changes direction is not feasible. , This refers to the number of approach lanes at the intersection. , This represents the number of traffic turns at the intersection.

[0006] Furthermore, the aforementioned entrance lanes include north entrance, east entrance, south entrance, and west entrance, and the traffic flow directions include going straight, turning left, and turning right.

[0007] Furthermore, in step S2, the formula is used... The remaining time for the overflow to dissipate at the current intersection is calculated. In the formula This represents the distance between the current intersection and the downstream intersection of the preceding intersection. The average distance between the front and rear of the vehicle. For the driver's reaction time, This represents the time elapsed since the queue overflow direction was first released, obtained from the real-time traffic lights of the downstream intersections at the current intersection.

[0008] Furthermore, in step S3, the formula is used... The benefit function was calculated. In the formula, Signal control strategy Extended time, and All are auxiliary variables. For control strategy Lead time for the lower signal , To control the number of strategies, ,when , , Indicates signal control strategy The first under the intersection The first import channel Traffic flow turning is controlled by the current phase. Indicates signal control strategy The first under the intersection The first import channel Traffic flow that changes direction is not controlled by the current phase. for The first intersection within the time limit The first import channel Traffic demand at each traffic flow turning point To extend The traffic flow demand that can pass through after the overflow dissipates in seconds.

[0009] Furthermore, the above signal control strategy This includes: switching to the next phase, extending the green light duration of the current phase, and keeping the current phase unchanged.

[0010] Furthermore, in step S4, the formula is used... Calculate the penalty term In the formula, , Indicates the first The first import channel Traffic flowing from one direction should not merge into the overflow direction at the current intersection. Indicates the current overflow intersection is... The first import channel Traffic flows that turn into the flow merge.

[0011] Furthermore, the signal control optimization model for step S5 is as follows: , In the formula, As decision variables, Indicates control strategy The current optimal strategy The overflow threshold, To maximize the duration, To adopt control strategies Minimum green light duration requirement for the next signal. This represents the remaining green light duration for the current phase. The current phase has been past the green light duration. The minimum green light duration for pedestrians crossing the street.

[0012] Preferably, when the current crossover is in a non-overflow state, The value is 100000; the current crossover occurs when an overflow is imminent. The value is 10000; when the current crossover is in an overflow state, The value is 100; when the current crossover is in an overflow state, The value is 1.

[0013] Furthermore, in step S6, the optimal decision variables are obtained by solving the signal control optimization model. and optimal decision variables Corresponding control strategy Optimal extension time , the optimal decision variables Corresponding control strategy and optimal extension time Convert the commands into signal control instructions and send the control instructions to the signal.

[0014] The beneficial effects of this invention are: (1) Proactive overflow prevention: By introducing overflow state mapping and downstream dissipation time calculation, this invention is no longer a passive response to congestion, but can predict the timing of overflow dissipation, and achieve proactive and precise release and interception. (2) Multi-objective collaborative optimization: The optimization model innovatively introduces an overflow deterioration penalty term, which, while pursuing the maximization of intersection capacity, forcibly suppresses the flow of traffic merging into the overflow direction, effectively avoiding systemic deadlock caused by local optima.

[0015] (3) Strong real-time performance: This method performs second-level calculations on real-time detection data (Radar / Electric Police), which can quickly respond to sudden situations of "imminent overflow" and make up for the shortcomings of long cycle and slow response of traditional adaptive control. (4) Good business compatibility: The model constraints fully consider actual business constraints such as pedestrian crossing and minimum green light time, ensuring the safety and feasibility of the algorithm in actual engineering applications. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overflow state; Figure 2 This is a schematic diagram of the overflow dissipation at the intersection; Figure 3 This is a schematic diagram of the overflow dissipation at the intersection. Detailed Implementation

[0017] The following is in conjunction with the appendix Figure 1 Appendix Figure 2 Appendix Figure 3 The present invention will be further described below.

[0018] A method for controlling intersection signals based on real-time overflow detection, comprising: S1. Obtain the mapping relationship between the current overflow status of the intersection and the passable traffic flow based on the real-time detection data of the intersection.

[0019] S2. Obtain the real-time traffic light status of the downstream intersections of the current intersection and calculate the remaining time for the overflow to dissipate at the current intersection. .

[0020] S3. Calculate the benefit functions under different signal control strategies based on the current signal control strategy and mapping relationship of the intersection. .

[0021] S4. Calculate the penalty term for the overflow state deteriorating into an overflow stop state. .

[0022] S5. Utilizing the benefit function and penalties Construct a signal control optimization model.

[0023] S6. Based on the signal control optimization model, obtain the optimal decision variables and optimal extension time, convert the control strategy corresponding to the optimal decision variables and the optimal extension time into signal control commands and send them to the signal controller.

[0024] It can significantly improve the level of intelligence in urban traffic signal control.

[0025] In one embodiment of the present invention, the first step S1 The first import channel The mapping relationship between traffic flow turning is as follows: ,when Time indicates the first The first import channel Traffic flow turning is feasible (without overflow obstruction), when Time indicates the first The first import channel Traffic flow that changes direction is not feasible. , This refers to the number of approach lanes at the intersection. , This represents the number of traffic turns at the intersection.

[0026] In this embodiment, the aforementioned entrance lanes include north entrance, east entrance, south entrance, and west entrance, and the traffic flow directions include going straight, turning left, and turning right.

[0027] In one embodiment of the present invention, step S2 is performed using the formula The remaining time for the overflow to dissipate at the current intersection is calculated. In the formula This represents the distance (in meters) between the current intersection and the downstream intersection of the preceding intersection. Average distance between the front of the vehicle (unit: meters). Driver's reaction time (in seconds). The current time (in seconds) is the time that the queue overflow direction has been allowed to proceed, obtained from the real-time traffic light status of the downstream intersections of the current intersection.

[0028] In one embodiment of the present invention, step S3 is performed using the formula The benefit function was calculated. In the formula, Signal control strategy Extended time, and These are all auxiliary variables used to determine the control strategy. Considering the effective green light duration after downstream overflow dissipates, For control strategy The lead time for exiting a signal is the green flashing time plus the yellow flashing time. The lead time for extending the green light duration of the current phase and keeping the current phase unchanged is the remaining green light duration of the current phase. , To control the number of strategies, ,when , , Indicates signal control strategy The first under the intersection The first import channel Traffic flow turning is controlled by the current phase. Indicates signal control strategy The first under the intersection The first import channel Traffic flow that changes direction is not controlled by the current phase. for The first intersection within the time limit The first import channel Traffic demand at each traffic flow turning point To extend The traffic flow demand that can be accommodated after the overflow dissipates in seconds. Benefit function. Signal control strategy The vehicle throughput under the control strategies of switching to the next phase and maintaining the current phase. . Used to calculate the extension of the current phase Traffic flow that can pass through per second Used to calculate the extension of the current phase If the overflow dissipates after a few seconds, the increased traffic flow will be... In this embodiment, the signal control strategy This includes: switching to the next phase, extending the green light duration of the current phase, and keeping the current phase unchanged (neither extending nor switching, waiting for the next calculation step).

[0029] In one embodiment of the invention, a penalty term is introduced to prevent overflow from deteriorating into a stopped overflow state. Definition In order to control strategy The more traffic flows into the overflow direction, the more severe the overflow situation will become. Specifically, in step S4, the formula is used... Calculate the penalty term In the formula, , Indicates the first The first import channel Traffic flowing from one direction should not merge into the overflow direction at the current intersection. Indicates the current overflow intersection is... The first import channel Traffic flows that turn into the flow merge.

[0030] In one embodiment of the present invention, the signal control optimization model for step S5 is as follows: (1) (2) (3) (4) (5) (6) (7); In the formula, As decision variables, Indicates control strategy The current optimal strategy The overflow threshold, To maximize the duration, To adopt control strategies Minimum green light duration requirement for the next signal (minimum pulse time of the signal). This represents the remaining green light duration for the current phase. The current phase has been past the green light duration. Let be the minimum green light duration for pedestrians crossing the street. The control objective of the optimization model is to select a suitable signal control strategy to maximize the intersection's capacity without worsening the intersection's overflow condition. Among the constraints, the formula for constraint (1) is used to ensure the current signal control strategy. Only one can be chosen. The formula for constraint (2) is used to ensure that the time is extended under phase switching. Set to 0, while ensuring that the time is extended under extended phase. The maximum extension time is In terms of business operations, it ensures passage in other directions. The formula for constraint (3) is used to ensure that control strategies are adopted. The remaining green light time for the current phase is at least [number] times. This constraint is a business constraint. The formula for constraint (4) is used to ensure that a control strategy is adopted. The current phase has elapsed for a duration greater than [a certain amount]. (e.g., minimum pedestrian crossing time). Constraints (5) and (6) are used to ensure the auxiliary variables and Values ​​should be taken within a reasonable range, i.e. For auxiliary variables Yes: When hour, ,otherwise, The formula for constraint (7) is used to ensure the range of values ​​for the variables, and the decision variables. and auxiliary variables All variables are 0-1, signal control strategy The extended time and auxiliary variables All are continuous variables.

[0031] In this embodiment, preferably, when the current crossover is in a non-overflow state, The value is 100000; the current crossover occurs when an overflow is imminent. The value is 10000; when the current crossover is in an overflow state, The value is 100; when the current crossover is in an overflow state, The value is 1.

[0032] In one embodiment of the present invention, the optimal decision variables are obtained by solving the signal control optimization model in step S6. and optimal decision variables Corresponding control strategy Optimal extension time , the optimal decision variables Corresponding control strategy and optimal extension time The process is converted into traffic signal control commands, which are then sent to the traffic signal. If the optimal strategy is to switch to the next phase, the traffic signal executes a phase-jump command, immediately terminating the current phase's green light, entering a flashing green / yellow phase, and jumping to the next phase. If the optimal strategy is to extend the current phase's green light duration, the traffic signal executes a temporary phase extension command, extending the current phase's green light time by a few seconds. If the optimal strategy is to maintain the current phase, the traffic signal neither extends nor switches, waiting for the next calculation step, while continuously monitoring the overflow status.

[0033] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling intersection signals based on real-time overflow detection, characterized in that, include: S1. Obtain the mapping relationship between the current overflow status of the intersection and the passable traffic flow based on the real-time detection data of the intersection; S2. Obtain the real-time traffic light status of the downstream intersections of the current intersection and calculate the remaining time for the overflow to dissipate at the current intersection. ; S3. Calculate the benefit functions under different signal control strategies based on the current signal control strategy and mapping relationship of the intersection. ; S4. Calculate the penalty term for the overflow state deteriorating into an overflow stop state. ; S5. Utilizing the benefit function and penalties Construct a signal control optimization model; S6. Based on the signal control optimization model, obtain the optimal decision variables and optimal extension time, convert the control strategy corresponding to the optimal decision variables and the optimal extension time into signal control commands and send them to the signal controller.

2. The intersection signal control method based on real-time overflow detection according to claim 1, characterized in that: In step S1 The first import channel The mapping relationship between traffic flow turning is as follows: ,when Time indicates the first The first import channel Traffic flow turning into a single flow is feasible, when Time indicates the first The first import channel Traffic flow that changes direction is not feasible. , This refers to the number of approach lanes at the intersection. , This represents the number of traffic turns at the intersection.

3. The intersection signal control method based on real-time overflow detection according to claim 2, characterized in that: The entrance lanes include the north entrance, east entrance, south entrance, and west entrance, and the traffic flow directions include going straight, turning left, and turning right.

4. The intersection signal control method based on real-time overflow detection according to claim 2, characterized in that: In step S2, the formula is used The remaining time for the overflow to dissipate at the current intersection is calculated. In the formula This represents the distance between the current intersection and the downstream intersection of the preceding intersection. The average distance between the front and rear of the vehicle. For the driver's reaction time, This represents the time elapsed since the queue overflow direction was first released, obtained from the real-time traffic lights of the downstream intersections at the current intersection.

5. The intersection signal control method based on real-time overflow detection according to claim 2, characterized in that: In step S3, the formula is used. The benefit function was calculated. In the formula, Signal control strategy Extended time, and All are auxiliary variables. For control strategy Lead time for the lower signal , To control the number of strategies, ,when , , Indicates signal control strategy The first under the intersection The first import channel Traffic flow turning is controlled by the current phase. Indicates signal control strategy The first under the intersection The first import channel Traffic flow that changes direction is not controlled by the current phase. for The first intersection within the time limit The first import channel Traffic demand at each traffic flow turning point To extend The traffic flow demand that can pass through after the overflow dissipates in seconds.

6. The intersection signal control method based on real-time overflow detection according to claim 5, characterized in that: The signal control strategy This includes: switching to the next phase, extending the green light duration of the current phase, and keeping the current phase unchanged.

7. The intersection signal control method based on real-time overflow detection according to claim 5, characterized in that: In step S4, the formula is used. Calculate the penalty term In the formula, , Indicates the first The first import channel Traffic flowing from one direction should not merge into the overflow direction at the current intersection. Indicates the current overflow intersection is... The first import channel Traffic flows that turn into the flow merge.

8. The intersection signal control method based on real-time overflow detection according to claim 5, characterized in that, The signal control optimization model for step S5 is as follows: ， In the formula, As decision variables, Indicates control strategy The current optimal strategy The overflow threshold, To maximize the duration, To adopt control strategies Minimum green light duration requirement for the next signal. This represents the remaining green light duration for the current phase. The current phase has been past the green light duration. The minimum green light duration for pedestrians crossing the street.

9. The intersection signal control method based on real-time overflow detection according to claim 8, characterized in that: When the current crossover is in a non-overflow state, The value is 100000; the current crossover occurs when an overflow is imminent. The value is 10000; when the current crossover is in an overflow state, The value is 100; when the current crossover is in an overflow state, The value is 1.

10. The intersection signal control method based on real-time overflow detection according to claim 8, characterized in that: In step S6, the optimal decision variables are obtained by solving the signal control optimization model. and optimal decision variables Corresponding control strategy Optimal extension time , the optimal decision variables Corresponding control strategy and optimal extension time Convert the commands into signal control instructions and send the control instructions to the signal.

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