A bus priority signal control method based on mobile bus phase time window

Abstract

The present invention discloses a bus priority signal control method based on a mobile bus phase time window. First, the bus time window is calculated in combination with bus speed fluctuations and theoretical arrival time points; secondly, a bus priority strategy set is established with the goal of covering the bus arrival time window with the green light time of the bus phase, without changing the bus phase duration and the overall phase structure. This signal adjustment method is a bus priority strategy that moves the bus phase time window based on the prediction of the bus arrival time to adapt to the public transportation demand; finally, bus signal priority control is implemented based on the strategy group. The present invention can minimize the encroachment of the green light time of other phases due to bus priority, avoid the failure of bus priority caused by errors in arrival time, excessive extension of bus phase duration and adjustment of the overall phase structure, and improve the overall traffic efficiency of the intersection.

Description

Technical Field

[0001] The invention belongs to the field of urban public transportation system and traffic signal control in traffic engineering, and in particular to a public transportation priority control method based on a mobile public transportation phase time window. Background Art

[0002] In recent years, the number of motor vehicles in my country has continued to grow, the spatial resources of urban road networks are limited, the contradiction between traffic supply and demand has become increasingly prominent, and urban traffic congestion has gradually become the norm. Public transportation has the advantages of less road resources per capita and large transportation volume. Giving priority to the development of urban public transportation systems and improving the transportation travel structure is one of the important strategies to effectively alleviate traffic congestion. As an important part of public transportation, the operating efficiency and service level of conventional ground buses can be effectively improved through bus signal priority. However, there are shortcomings in the existing bus signal priority methods, such as the limited applicability of bus priority strategies and the difficulty in balancing the travel benefits of buses and motor vehicles, which greatly limit the full play of the benefits of bus priority. Therefore, in-depth research on these problems and proposing effective solutions is an urgent task to improve the applicability of bus priority and improve the implementation effect.

[0003] At present, my country has been exploring reasonable implementation plans for bus priority control, but bus signal priority has not been well used in Chinese cities. The main reason is that there are technical defects. Bus priority signal control mainly includes two key steps: (1) predicting the time when the bus arrives at the stop line; (2) adopting the corresponding bus priority strategy. Only when the prediction is accurate and the priority strategy is appropriate can effective bus priority be achieved. For step one, the current prediction method actually used in my country often predicts the time point of bus arrival, and then adjusts the phase with the purpose of including the time point in the bus phase, but fails to fully consider the real-time fluctuation characteristics of bus speed. For step two, the current bus priority strategy actually used is mainly to extend the green light of the bus phase, early red light off and phase insertion, etc. The flexibility of the bus phase to adapt to the arrival of the bus is insufficient; in addition, excessively increasing the green light duration of the bus phase and disrupting the original phase structure are also important defects of the existing bus priority strategy.

[0004] The above-mentioned background technology methods lead to the following problems in the bus priority signal control system: (1) The predicted bus arrival time is limited: only one time point is selected as the predicted bus arrival time, or only an approximate arrival time interval is estimated, and the reliable time window for the bus to arrive at the intersection is not calculated from the perspective of bus priority benefits. The fluctuation of bus speed is not considered enough, and the robustness of the prediction method is low, resulting in the lack of a basis for the correct implementation of the corresponding bus priority strategy; (2) The bus priority control strategy is low in practicality: the bus priority strategy remains at a relatively basic violent priority stage, and the priority method fails to take into account the bus priority benefits, social vehicle rights, and the phase communication of each signal. (1) Considering the overall efficiency of public transportation, the flexibility and practicality are insufficient; (2) Damage to the rights and interests of social vehicles: The current bus priority strategy often fails to balance the rights and interests of public transportation and social vehicles, excessively increases the duration of bus phases, disrupts the original phase structure, and causes large delays for social vehicles; (3) The overall traffic efficiency of intersections is not ideal: Under the combined effect of the above two reasons, signal priority control fails to effectively improve the bus priority rate, but leads to damage to the rights and interests of social vehicles. In general, the defects of bus arrival time prediction methods and bus priority strategies may lead to a decrease in the actual overall traffic efficiency of intersections, ultimately making bus priority control more harmful than beneficial. Summary of the invention

[0005] The purpose of the present invention is to improve the bus arrival time prediction method in bus priority control in view of the problems existing in the prior art, and to propose a more flexible and effective bus priority control strategy, so as to better adapt the predicted bus arrival time to the bus priority signal control strategy, improve the bus priority passing rate, balance the rights and interests of buses and social vehicles, and ultimately achieve the purpose of improving the traffic efficiency of the entire intersection.

[0006] The technical solution to achieve the purpose of the present invention is: a bus priority control method based on a mobile bus phase time window, which expands the bus theoretical arrival time point obtained by calculation into the bus arrival time window, adjusts the bus phase time window with the goal of completely covering the bus time window with the green light time of the bus phase, and establishes a bus priority strategy set with bus phase forward / backward shift as the main method and non-bus phase compression / stretching as the auxiliary method without changing the bus phase duration and the overall phase structure, and improves the bus priority benefit by combining the bus arrival time window with strong robustness and the bus priority strategy with strong flexibility.

[0007] The method specifically comprises the following steps:

[0008] Step S1, calculate the bus time window in combination with bus speed fluctuation and theoretical arrival time point: predict the bus arrival time at the stop line, combine the bus arrival detector time and the bus travel speed fluctuation characteristics, preliminarily calculate the bus arrival time interval based on the theoretical arrival time point, and then consider the stability of the overall structure of the signal phase, in order to prevent the bus phase from moving too much to cover the bus arrival time window, further establish a model to calculate the bus arrival time window as the basis for the implementation of the corresponding bus priority control strategy;

[0009] Step S2, establish a bus priority strategy based on the bus phase time window: in order to reduce the negative impact on social vehicles when performing bus priority control, the timing plan is adjusted with the goal of covering the bus time window with the green light time of the bus phase, without changing the bus phase duration and the overall structure of the signal phase. According to the adjustment characteristics of each phase, i.e., the changes in the start and end times and phase length, the priority strategy set based on the bus time window is divided into four basic strategies: phase advance, phase retreat, phase compression and phase stretch; the strategy set can be further divided into two bus priority control strategy groups for different bus arrival situations: (1) When the bus arrival time window is before the original bus phase start time, a strategy group that implements bus phase advance and non-bus phase compression and compensation; (2) When the bus arrival time window is after the original bus phase end time, a strategy group that implements bus phase retreat and non-bus phase stretch;

[0010] Step S3, establish the overall bus priority control logic: according to the characteristics of the bus when issuing the request, combine the two bus priority control strategy groups consisting of the four basic strategies in step S2, design the timing plan and calculate the green light time adjustment amount and start and end time of each phase to form the final bus priority control plan.

[0011] Furthermore, step S1 calculates the bus time window in combination with the bus speed fluctuation and the theoretical arrival time point, specifically including:

[0012] Step S1-1, extract the distance D between the bus and the stop line at the current time T0 bus and theoretical travel speed Calculate the theoretical time point when the bus arrives at the stop line

[0013]

[0014] Step S1-2: Based on the historical data of bus operation, the confidence interval and upper and lower limits of the bus travel speed are estimated using the interval estimation method in probability statistics. Must meet

[0015] Calculate the time difference between the earliest and latest arrival of the bus at the stop line based on the distance and the upper and lower limits of the travel speed, and combine it with the bus time window length threshold Calculate the length of the bus time window

[0016]

[0017] Step S1-3, according to the theoretical arrival time point and the length of the bus time window Calculate the start and end times of the bus time window; introduce the time window offset factor α into the calculation formula of the bus time window win , 0≤α win ≤1, when the factor is greater than 0.5, the bus time window will be biased towards the earliest arrival time; when the factor is less than 0.5, the bus time window will be biased towards the latest arrival time;

[0018] ① If the theoretical arrival time point is closer to the earliest arrival time in the predicted arrival time interval, then When the bus time window opens, the priority is to determine the opening time of the bus time window. Determine closing time

[0019] ② If the theoretical arrival time point is closer to the latest arrival time in the predicted arrival time interval, then When the bus time window is closed, the closing time is determined first. Determine the start time

[0020] Furthermore, the specific calculation formula for the start and end time of each phase in the signal cycle before and after the implementation of the basic strategy in step 2 is:

[0021]

[0022]

[0023]

[0024] In the formula, are the start and end times of the current cycle c respectively; are the green light on and off times of phase i in the cycle, i=1,...,n, n is the phase number; are the green light on and off times of phase i in the cycle after the implementation of the bus priority strategy, i=1,...,n; The running time of the current cycle, in seconds; C 0 is the duration of the background cycle, in seconds; I i is the green light interval of phase i in the background cycle, in seconds; are the green light time of phase i and j in the background cycle, in seconds; They are the green light time of phase i and j in the current cycle after the implementation of the bus priority strategy, in seconds.

[0025] Furthermore, the basic strategy in step S2 is specifically:

[0026] 1) Phase forward strategy: When the bus time window is before the green light on time of the bus phase, all phases that have not been completed before the bus phase are compressed, and the green light time of the bus phase is turned on in advance; this strategy moves the bus phase without changing its green light duration, and its scheme adjustment characteristics are as follows: and

[0027] 2) Phase shift strategy: When the bus time window is after the green light on time of the bus phase, all the phases that have not been completed before the bus phase are stretched to delay the green light time of the bus phase; this strategy moves the bus phase without changing its green light duration. Its scheme adjustment characteristics are: and

[0028] 3) Phase compression strategy: This strategy will be executed in the following cases: When the phase forward strategy is adopted to adjust the signal scheme, the compressed phase is adjusted; this strategy is aimed at non-transit phases and unrequested transit phases, reducing their green light duration, and its scheme adjustment characteristics are

[0029] 4) Phase stretching strategy: This strategy will be implemented in two cases: (1) When the phase shift strategy is adopted to adjust the signal scheme, the stretched phase is adjusted; (2) When the non-transit phase is compressed by the bus phase forward strategy, it needs to be compensated. In the next cycle of bus priority, the non-transit phase is stretched, and the stretching time of each phase should be enough to make up for the green light time damaged by compression. This strategy increases the green light time of the non-transit phase, and its scheme adjustment characteristics are as follows:

[0030] Furthermore, in step S3, the overall bus priority control logic is established, and the specific process includes:

[0031] Step S3-1: Count the currently generated bus requests and determine their bus time windows; determine the priority of the bus vehicles based on the theoretical arrival time of the bus requests, i.e., the midpoint of the bus time window. The total number of requests is k; are the opening time, theoretical time point and closing time of the bus time window corresponding to the kth request respectively;

[0032] Step S3-2, determine the current running phase number is h and the green light running time Take the first bus request As a benchmark, determine the target phase number i to which the request belongs; select the first k1 (≥1) bus requests belonging to the target phase i in the priority order, and ignore the subsequent requests belonging to other phases. The result is Determine the earliest time when the bus arrives at the stop line among k1 requests and the latest time

[0033] Step S3-3: If the maximum arrival time difference of the first k1 requests does not exceed the green light duration of the bus phase, Determine the forward or backward shift amount of bus phase i, implement the phase shift strategy for the bus phase, and determine the priority strategy type for other phases, as follows:

[0034] ① If the bus time window is within the green light period of the bus phase, that is and It is not necessary to implement a bus priority strategy to ensure smooth bus traffic;

[0035] ② If the bus time window is before the green light period of the bus phase, that is At this time, the bus phase forward shift and non-bus phase compression and compensation strategy group is implemented to calculate the theoretical forward shift of the bus phase respectively. and the maximum forward shift of the bus phase at the current moment in is the minimum green light time;

[0036] When the theoretical forward displacement does not exceed the maximum forward displacement, When the phase is forward, the strategy of phase shifting is implemented to ensure that buses pass through the intersection without stopping by evenly compressing other phases;

[0037] When the theoretical forward displacement exceeds the maximum forward displacement, When the phase is forwarded, the strategy of phase shift is implemented to compress other phases to the minimum green light time and compress phase h to Reduce bus stopping delays when stopping behavior is unavoidable;

[0038] After the phase advance and phase compression strategies are implemented, the green light time of the non-public transportation phase is compensated in the next cycle, and the green light stretching strategy of the non-public transportation phase is implemented. The stretching time of each phase should just make up for the green light time damaged by compression in the previous cycle;

[0039] ③ If the bus time window is after the green light period of the bus phase, that is At this time, the bus phase shift and non-bus phase stretch strategy group is implemented, and the theoretical shift amount of the bus phase is calculated respectively. and the maximum backward shift of the bus phase at the current moment in is the maximum green time;

[0040] When the theoretical back displacement does not exceed the maximum back displacement, that is When the phase is shifted back, the strategy of phase shifting is implemented to ensure that buses can pass through the intersection without stopping by evenly stretching other phases;

[0041] When the theoretical back displacement exceeds the maximum back displacement, When the public transport priority strategy is not implemented;

[0042] Step S3-4: If the maximum arrival time difference of the first k1 requests exceeds the green light duration of the bus phase, Then, redundant bus priority requests are gradually deleted, so that the maximum arrival time difference of the buses in the bus priority requests to be responded to does not exceed the green light duration of the bus phase; the specific calculation method is: if Delete the last bus request k1 and update the bus request set K1 set , go to step S3-3 and recalculate.

[0043] Compared with the prior art, the present invention has the following significant advantages:

[0044] (1) Improving the robustness of bus priority control: The present invention is not limited to using time points as predicted bus arrival times, but obtains the time window for bus arrival at intersections through theoretical calculations, which provides a strong basis for the implementation of corresponding bus priority strategies and helps to improve the bus priority passing rate.

[0045] (2) Improving the flexibility of bus priority control: The present invention proposes a more flexible bus priority strategy set to flexibly respond to bus priority requests and reduce bus delays, thereby improving the effectiveness of bus priority control.

[0046] (3) Safeguarding the rights and interests of social vehicles: The present invention ensures that the duration of the bus phase and the overall phase structure remain unchanged. While implementing bus priority, the rights and interests of social vehicles are taken into consideration as much as possible to prevent social vehicles from being excessively delayed due to bus priority.

[0047] (4) Improving the overall traffic efficiency of intersections: The present invention proposes an innovative prediction method and priority strategy to improve the bus priority control level from the entire bus priority process, thereby improving the overall traffic efficiency of intersections.

[0048] The present invention is further described in detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a logical schematic diagram of bus signal priority control of the present invention.

[0050] Figure 2 It is a schematic diagram of the phase forward shift strategy.

[0051] Figure 3 It is a schematic diagram of the phase-shift strategy.

[0052] Figure 4 It is a schematic diagram of the phase compression strategy.

[0053] Figure 5 It is a schematic diagram of the phase stretching strategy. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0055] It should be noted that if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0056] In one embodiment, in combination Figure 1 , a bus priority control method based on mobile bus phase time window is proposed, the method includes the following steps:

[0057] 1) Predict the time when the bus arrives at the stop line, combine the bus arrival detector time and the travel speed fluctuation characteristics of the bus, preliminarily calculate the bus arrival time interval based on the theoretical arrival time point, and then consider the stability of the overall structure of the signal phase to prevent the bus phase from moving too much to cover the bus arrival time window. Further establish a model to calculate the bus arrival time window as the basis for the implementation of the corresponding bus priority control strategy.

[0058] The calculation method of the bus time window is as follows:

[0059] S1-1. Extract the distance D between the bus and the stop line at the current time T0 bus (Unit: m) and theoretical travel speed (Unit: m / s), calculate the theoretical time point when the bus arrives at the stop line

[0060] S1-2. Based on the historical data of bus operation, the confidence interval and upper and lower limits of bus travel speed are estimated using the interval estimation method in probability statistics. (Unit: m / s), which must meet Calculate the time difference between the earliest and latest arrival of the bus at the stop line based on the distance and the upper and lower limits of the travel speed, and combine it with the bus time window length threshold (Unit: s), construct the length of the bus time window (Unit: s) calculation method. Among them, is the preset length threshold. This length limit can avoid excessive movement of the bus phase due to excessive fluctuations in the bus arrival time, thereby calibrating a relatively stable bus time window and preventing the overall phase structure from being damaged. Its value should not exceed the green light time of the bus phase, and it is recommended to take [5, 10]s:

[0061]

[0062] S1-3, according to the theoretical arrival time point and the length of the bus time window Calculate the start and end times of the bus time window. Introduce the time window offset factor α into the calculation formula of the bus time window win (0≤α win ≤1), when the factor is greater than 0.5, the bus time window will be biased towards the earliest arrival time; when the factor is less than 0.5, the bus time window will be biased towards the latest arrival time. In engineering practice, in order to improve the situation where the bus is forced to stop and wait for the next green light due to the actual arrival time being later than the predicted time, the bus time window can be biased towards the latest arrival time as much as possible, and 1 / 3 is recommended:

[0063] ① If the theoretical arrival time point is closer to the earliest arrival time in the predicted arrival time interval, then When the bus time window opens, the priority is to determine the opening time of the bus time window. Determine closing time

[0064] ② If the theoretical arrival time point is closer to the latest arrival time in the predicted arrival time interval, then When the bus time window is closed, the closing time is determined first. Determine the start time

[0065] 2) Determine the degree of deviation between the bus arrival time window and the green light time of the bus phase. In order to reduce the negative impact on social vehicles when performing bus priority control, the timing plan is adjusted with the goal of covering the bus time window with the green light time of the bus phase, with the premise of not changing the bus phase duration and the overall structure of the signal phase as much as possible. According to the adjustment characteristics of each phase, namely the changes in the start and end times and phase length, the priority strategy based on the bus time window is divided into four basic strategies: phase advance, phase delay, phase compression and phase stretch. This strategy set can be further divided into two strategy groups for different bus arrival situations: (1) When the bus arrival time window is before the original bus phase start time, the strategy group implements bus phase advance and non-bus phase compression and compensation, where compensation is to stretch the non-bus phase in the next cycle after the implementation of bus priority to compensate for the green light time loss caused by phase compression; (2) When the bus arrival time window is after the original bus phase end time, the strategy group implements bus phase delay and non-bus phase stretch.

[0066] The specific meanings of the four strategies are as follows:

[0067] (1) Phase forward: When a bus request is detected at the entrance, and it is predicted that the bus phase will not be on when the bus arrives, the bus phase will be appropriately moved forward without changing the phase duration to ensure that the bus passes without stopping or reduce the waiting time. This signal adjustment method is called phase forward. After the bus leaves the intersection, the original timing plan is restored. The early red light off strategy extends the green light time for the bus by compressing the previous phase. Phase forward compresses all phases from the current phase to the bus phase, but does not extend the green light time for the bus phase.

[0068] Taking the four-phase timing scheme as an example, the signal period adjustment method based on the phase advance strategy is generally as follows: Figure 2 As shown, the bus phase is shifted forward and the other phases correspondingly implement compression strategies.

[0069] (2) Phase shift: When a bus request is detected at the entrance, it is predicted that the bus phase will just be closed when the bus arrives. In this way, the bus phase will be appropriately shifted back without changing the phase duration to avoid being forced to stop and wait for the green light time of the next cycle. This signal adjustment method is called phase shift. After the bus leaves the intersection, the original timing plan is restored. The green light extension strategy extends the green light time for the bus by compressing the subsequent phases within the cycle. Phase shift extends all phases from the current phase to the bus phase, but does not extend the green light time for the bus phase.

[0070] Taking the four-phase timing scheme as an example, the signal period adjustment method based on the phase shift strategy is generally as follows: Figure 3 As shown, the bus phase is shifted back and the other phases accordingly implement the stretching strategy.

[0071] (3) Phase compression: When the forward shift strategy is implemented for the bus phase, the preceding non-bus phase will also implement the phase compression strategy. This can also be used for unrequested bus phases when there is competition among multiple bus lines. For the phases that adopt the compression strategy, their start and end times and length will change.

[0072] Taking the four-phase timing scheme as an example, the signal period adjustment method based on the combination of phase compression and phase advance is generally as follows: Figure 4 As shown, the bus phase implements the forward shift strategy, while the other phases implement the compression strategy.

[0073] (4) Phase stretching: When the bus phase is retracted, the preceding non-bus phase will be stretched accordingly. When compensating for the compressed phase, the phase stretching strategy will also be applied to it. For the phase that adopts the stretching strategy, its start and end time and length will change.

[0074] Taking the four-phase timing scheme as an example, the signal period adjustment method based on the combination of phase stretching and phase shifting is generally as follows: Figure 5 As shown, the bus phase implements the backward strategy, and the other phases implement the stretching strategy.

[0075] After implementing the basic strategy, the specific calculation method of the start and end time of each phase in the signal cycle is:

[0076]

[0077]

[0078]

[0079] In the formula, are the start and end times of the current cycle c respectively; are the green light on and off times of phase i in the cycle, i=1,...,n, n is the phase number; are the green light on and off times of phase i in the cycle after the implementation of the bus priority strategy, i=1,...,n; The running time of the current cycle, in seconds; C 0 is the duration of the background cycle, in seconds; I i is the green light interval of phase i in the background cycle, in seconds; are the green light time of phase i and j in the background cycle, in seconds; They are the green light time of phase i and j in the current cycle after the implementation of the bus priority strategy, in seconds.

[0080] S2-1, Phase forward strategy: When the bus time window is before the green light on time of the bus phase, all phases that have not been completed before the bus phase are compressed, and the green light time of the bus phase is turned on in advance. This strategy moves the bus phase without changing the green light duration. Its scheme adjustment characteristics are: and

[0081] S2-2, Phase shift strategy: When the bus time window is after the green light on time of the bus phase, stretch all the phases that have not been completed before the bus phase, and delay the green light time of the bus phase. This strategy moves the bus phase without changing the green light duration. Its solution adjustment characteristics are: and

[0082] S2-3, Phase compression strategy: When the basic strategy such as phase forward adjustment is adopted to adjust the signal scheme, the compressed phase is adjusted. This strategy is mainly aimed at non-public transportation phases and unrequested public transportation phases, reducing their green light duration. Its scheme adjustment characteristics are as follows:

[0083] S2-4, Phase stretching strategy: This strategy will be implemented in two cases: (1) When the phase shift strategy is adopted to adjust the signal scheme, the stretched phase is adjusted; (2) When the non-transit phase is compressed by the bus phase forward strategy, it needs to be compensated. In the next cycle of bus priority, the non-transit phase is stretched to make up for the green light time damaged by compression. This strategy is mainly aimed at the non-transit phase, increasing its green light duration, and its scheme adjustment characteristics are as follows:

[0084] 3) According to the characteristics of the bus when issuing the request, the basic strategy in S2 is combined to design the timing plan and calculate the green light time adjustment and start and end times of each phase to form the final bus priority control plan.

[0085] The bus signal priority control logic is designed based on the basic priority strategy. The specific implementation method is as follows:

[0086] S3-1. Count the currently generated bus requests and determine their bus time windows; determine the priority of the buses based on the theoretical arrival time of the bus requests, i.e. the midpoint of the bus time window. The total number of requests is k.

[0087] S3-2, determine the current phase number h and the green light operation time Take the first bus request As a benchmark, determine the target phase number i to which the request belongs; select the first k1 (≥1) bus requests belonging to the target phase i in the priority order, and ignore the subsequent requests belonging to other phases. The result is Determine the earliest time when the bus arrives at the stop line among k1 requests and the latest time

[0088] S3-3. If the maximum arrival time difference of the first k1 requests does not exceed the green light duration of the bus phase Determine the forward or backward shift amount of bus phase i, implement a phase shift strategy for the bus phase, and determine the priority strategy type for other phases.

[0089] ① If the bus time window is within the green light period of the bus phase, that is and There is no need to implement a bus priority strategy to ensure smooth bus traffic.

[0090] ② If the bus time window is before the green light period of the bus phase, that is At this time, the bus phase forward shift and non-bus phase compression and compensation strategy group is implemented to calculate the theoretical forward shift of the bus phase respectively. and the maximum forward shift of the bus phase at the current moment in The minimum green light time.

[0091] When the theoretical forward displacement does not exceed the maximum forward displacement, that is The phase forward strategy is implemented at the same time, and other phases are evenly compressed to ensure that buses can pass through the intersection without stopping;

[0092] When the theoretical forward displacement exceeds the maximum forward displacement, When the phase is forwarded, the other phases are compressed to the minimum green light time and the phase h is compressed to Minimize bus stopping delays when stopping behavior cannot be avoided.

[0093] After the phase advance and phase compression strategies are implemented, the green light time of the non-public transportation phase will be compensated in the next cycle, and the green light stretching strategy of the non-public transportation phase will be implemented. The stretching time of each phase should just make up for the green light time damaged by compression in the previous cycle.

[0094] ③ If the bus time window is after the green light period of the bus phase, that is At this time, the bus phase shift and non-bus phase stretch strategy group is implemented, and the theoretical shift amount of the bus phase is calculated respectively. and the maximum backward shift of the bus phase at the current moment in is the maximum green time.

[0095] When the theoretical back displacement does not exceed the maximum back displacement, that is The phase shift strategy is implemented at the same time, and other phases are stretched evenly to ensure that buses can pass through the intersection without stopping;

[0096] When the theoretical back displacement exceeds the maximum back displacement, The bus priority strategy is not implemented.

[0097] S3-4, if the maximum arrival time difference of the first k1 requests exceeds the green light duration of the bus phase Then, redundant bus priority requests are gradually deleted, so that the maximum arrival time difference of buses in the bus priority requests to be responded to does not exceed the green light duration of the bus phase. The specific calculation method is: Delete the last bus request k1 and update the bus request set K1 set , go to S3-3 and recalculate.

[0098] In one embodiment, a bus priority control system based on a mobile bus phase time window is provided, the system comprising:

[0099] The first module is used to calculate the bus time window by combining bus speed fluctuations and theoretical arrival time points;

[0100] The second module is used to establish a bus priority strategy based on bus phase time windows: according to the adjustment characteristics of each phase, i.e., the change of the start and end time and the phase length, the priority strategy based on the bus time window is divided into four basic strategies: phase advance, phase delay, phase compression and phase stretch; this strategy set can be further divided into two bus priority control strategy groups for different bus arrival situations: (1) when the bus arrival time window is before the original bus phase start time, the strategy group implements bus phase advance and non-bus phase compression and compensation; (2) when the bus arrival time window is after the original bus phase end time, the strategy group implements bus phase delay and non-bus phase stretch;

[0101] The third module is used to establish the overall bus priority control logic: according to the characteristics of the bus when issuing a request, the two bus priority control strategy groups consisting of the above four basic strategies are combined to design the timing plan and calculate the green light time adjustment amount and start and end times of each phase to form the final bus priority control plan.

[0102] For the specific limitations of the bus priority control system based on the mobile bus phase time window, please refer to the limitations of the bus priority control method based on the mobile bus phase time window above, which will not be repeated here. Each module in the above-mentioned bus priority control system based on the mobile bus phase time window can be implemented in whole or in part through software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0103] The above-mentioned bus priority method and system may involve the following parts: detectors, information processing equipment, and traffic signal control equipment.

[0104] 1. Detector: The detection system is compatible with various types of detectors, including GPS, RFID, video detector, coil detector, radar detector, geomagnetic detector, radar vision detector and other detectors.

[0105] 2. Traffic information processing equipment: used to transmit the bus arrival information obtained by the detector to the traffic signal control equipment.

[0106] 3. Traffic signal control equipment: that is, the signal machine, which is the main body for social vehicle signal control and bus priority control. The signal machine generates signal timing and bus priority plan according to the vehicle arrival information transmitted back by the information processing equipment, and drives the signal light color display.

[0107] The detectors, information processing equipment, and traffic signal control equipment described above are all prior art.

[0108] The present invention utilizes detectors, information processing equipment and traffic signals in the prior art to perform bus priority control based on bus time windows, calculates the bus time window according to bus arrival information obtained by the detector, generates a corresponding bus priority control strategy, and implements a control process.

[0109] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the computer program:

[0110] S1, calculate the bus time window by combining bus speed fluctuation and theoretical arrival time point;

[0111] S2, establish a bus priority strategy based on bus phase time window: according to the adjustment characteristics of each phase, i.e., the change of start and end time and phase length, the priority strategy set based on bus time window is divided into four basic strategies: phase advance, phase delay, phase compression and phase stretch; this strategy set can be further divided into two bus priority control strategy groups for different bus arrival situations: (1) when the bus arrival time window is before the original bus phase start time, the strategy group that implements bus phase advance and non-bus phase compression and compensation; (2) when the bus arrival time window is after the original bus phase end time, the strategy group that implements bus phase delay and non-bus phase stretch;

[0112] S3, establish the overall bus priority control logic: according to the characteristics of the bus when issuing the request, combine the two bus priority control strategy groups consisting of the four basic strategies in step S2, design the timing plan and calculate the green light time adjustment amount and start and end time of each phase to form the final bus priority control plan.

[0113] For the specific limitations of each step, please refer to the limitations of the bus priority control method based on the mobile bus phase time window in the above text, which will not be repeated here.

[0114] In one embodiment, a computer readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the following steps are implemented:

[0115] S1, calculate the bus time window by combining bus speed fluctuation and theoretical arrival time point;

[0116] S2, establish a bus priority strategy based on bus phase time window: according to the adjustment characteristics of each phase, i.e., the change of start and end time and phase length, the priority strategy set based on bus time window is divided into four basic strategies: phase advance, phase delay, phase compression and phase stretch; this strategy set can be further divided into two bus priority control strategy groups for different bus arrival situations: (1) when the bus arrival time window is before the original bus phase start time, the strategy group that implements bus phase advance and non-bus phase compression and compensation; (2) when the bus arrival time window is after the original bus phase end time, the strategy group that implements bus phase delay and non-bus phase stretch;

[0117] S3, establish the overall bus priority control logic: according to the characteristics of the bus when issuing the request, combine the two bus priority control strategy groups consisting of the four basic strategies in step S2, design the timing plan and calculate the green light time adjustment amount and start and end time of each phase to form the final bus priority control plan.

[0118] For the specific limitations of each step, please refer to the limitations of the bus priority control method based on the mobile bus phase time window in the above text, which will not be repeated here.

[0119] In summary, the bus priority control method based on bus time window proposed in the present invention expands the theoretical time point of bus arrival at the stop line into a time interval based on the bus speed fluctuation characteristics, establishes a model to calculate the bus arrival time window, and takes the green light time of the bus phase to completely cover the bus time window as the goal. On the basis of not changing the bus phase duration and the overall phase structure, the start and end times of the bus phase, that is, the bus phase time window, are flexibly adjusted to ensure the smooth passage of buses. According to the characteristics of the predicted arrival time of the bus, the start and end times and duration of the bus phase, a strategy group of bus phase forward shift and non-bus phase compression and compensation, or a strategy group of bus phase backward shift and non-bus phase stretching is proposed to further realize bus signal priority control. The present invention can minimize the encroachment of other phase green light times due to bus priority, avoid the failure of bus priority caused by errors in arrival time, excessive extension of bus phase duration and adjustment of the overall phase structure, and improve the overall traffic efficiency of the intersection.

[0120] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A bus priority signal control method based on a mobile bus phase time window, characterized in that: The method comprises the following steps: Step S1, calculating the bus time window in combination with bus speed fluctuation and theoretical arrival time point; Step S2, establish a bus priority strategy based on bus phase time window: according to the adjustment characteristics of each phase, i.e., the change of the start and end time and the phase length, the priority strategy set based on the bus time window is divided into four basic strategies: phase advance, phase delay, phase compression and phase stretch; the priority strategy set is further divided into two bus priority control strategy groups for different bus arrival situations: (1) when the bus arrival time window is before the original bus phase start time, a strategy group that implements bus phase advance and non-bus phase compression and compensation; (2) when the bus arrival time window is after the original bus phase end time, a strategy group that implements bus phase delay and non-bus phase stretch; Step S3, establishing the overall bus priority control logic: according to the characteristics of the bus when making a request, the two bus priority control strategy groups consisting of the four basic strategies in step S2 are combined to design a timing plan and calculate the green light time adjustment amount and start and end time of each phase to form a final bus priority control plan; Step S1 calculates the bus time window based on bus speed fluctuations and theoretical arrival time points, specifically including: Step S1-1, extract the distance D between the bus and the stop line at the current time T0 bus and theoretical travel speed Calculate the theoretical time point when the bus arrives at the stop line Step S1-2: Based on the historical data of bus operation, the confidence interval and upper and lower limits of the bus travel speed are estimated using the interval estimation method in probability statistics. Must meet Calculate the time difference between the earliest and latest arrival of the bus at the stop line based on the distance and the upper and lower limits of the travel speed, and combine it with the bus time window length threshold Calculate the length of the bus time window Step S1-3, according to the theoretical arrival time point and bus time window length Calculate the start and end times of the bus time window; introduce the time window offset factor α into the calculation formula of the bus time window win , 0≤α win ≤1, when the factor is greater than 0.5, the bus time window will be biased towards the earliest arrival time; when the factor is less than 0.5, the bus time window will be biased towards the latest arrival time; ① If the theoretical arrival time point is closer to the earliest arrival time in the predicted arrival time interval, then When the bus time window opens, the priority is to determine the opening time of the bus time window. Determine closing time ② If the theoretical arrival time point is closer to the latest arrival time in the predicted arrival time interval, then When the bus time window is closed, the closing time is determined first. Determine the start time 2. The bus priority signal control method based on mobile bus phase time window according to claim 1 is characterized in that: The specific calculation formula for the start and end time of each phase in the signal cycle before and after the implementation of the basic strategy in step 2 is: In the formula, are the start and end times of the current cycle c respectively; are the green light on and off times of phase i in the cycle, i=1,...,n, n is the phase number; are the green light on and off times of phase i in the cycle after the implementation of the bus priority strategy, i=1,...,n; The running time of the current cycle, in seconds; C o is the duration of the background cycle, in seconds; I j is the green light interval of phase i in the background cycle, in seconds; are the green light time of phase i and j in the background cycle, in seconds; They are the green light time of phase i and j in the current cycle after the implementation of the bus priority strategy, in seconds.

3. The bus priority signal control method based on mobile bus phase time window according to claim 2 is characterized in that: The basic strategy in step S2 is specifically: 1) Phase forward strategy: When the bus time window is before the green light on time of the bus phase, all phases that have not been completed before the bus phase are compressed, and the green light time of the bus phase is turned on in advance; this strategy moves the bus phase without changing its green light duration, and its scheme adjustment characteristics are as follows: and 2) Phase shift strategy: When the bus time window is after the green light on time of the bus phase, all the phases that have not been completed before the bus phase are stretched to delay the green light time of the bus phase; this strategy moves the bus phase without changing its green light duration. Its scheme adjustment characteristics are: and 3) Phase compression strategy: This strategy will be executed in the following cases: When the phase forward strategy is adopted to adjust the signal scheme, the compressed phase is adjusted; this strategy is aimed at non-transit phases and unrequested transit phases, reducing their green light duration, and its scheme adjustment characteristics are 4) Phase stretching strategy: This strategy will be implemented in two cases: (1) When the phase shift strategy is adopted to adjust the signal scheme, the stretched phase is adjusted; (2) When the non-transit phase is compressed by the bus phase forward strategy, it needs to be compensated. In the next cycle of bus priority, the non-transit phase is stretched, and the stretching time of each phase should be enough to make up for the green light time damaged by compression. This strategy increases the green light time of the non-transit phase, and its scheme adjustment characteristics are as follows:

4. The bus priority signal control method based on mobile bus phase time window according to claim 1 is characterized in that: In step S3, the overall bus priority control logic is established, and the specific process includes: Step S3-1: Count the currently generated bus requests and determine their bus time windows; determine the priority of the bus vehicles based on the theoretical arrival time of the bus requests, i.e., the midpoint of the bus time window. The total number of requests is k; are the opening time, theoretical time point and closing time of the bus time window corresponding to the kth request respectively; Step S3-2, determine the current running phase number is h and the green light running time Take the first bus request As a benchmark, determine the target phase number i to which the request belongs; select the first k1 bus requests belonging to the target phase i in the priority order, and ignore the subsequent requests belonging to other phases. The result is Determine the earliest time when the bus arrives at the stop line among k1 requests and the latest time Step S3-3: If the maximum arrival time difference of the first k1 requests does not exceed the green light duration of the bus phase, Determine the forward or backward shift amount of bus phase i, implement the phase shift strategy for the bus phase, and determine the priority strategy type for other phases, as follows: ① If the bus time window is within the green light period of the bus phase, that is and It is not necessary to implement a bus priority strategy to ensure smooth bus traffic; ② If the bus time window is before the green light period of the bus phase, that is At this time, the bus phase forward shift and non-bus phase compression and compensation strategy group is implemented to calculate the theoretical forward shift of the bus phase respectively. and the maximum forward shift of the bus phase at the current moment in is the minimum green light time; When the theoretical forward displacement does not exceed the maximum forward displacement, When the phase shift strategy is implemented, By uniformly compressing other phases, public transport vehicles can pass through the intersection without stopping; When the theoretical forward displacement exceeds the maximum forward displacement, When the phase is forwarded, the strategy of phase shift is implemented to compress other phases to the minimum green light time and compress phase h to Reduce bus stopping delays when stopping behavior is unavoidable; After the phase advance and phase compression strategies are implemented, the green light time of the non-public transportation phase is compensated in the next cycle, and the green light stretching strategy of the non-public transportation phase is implemented. The stretching time of each phase should just make up for the green light time damaged by compression in the previous cycle; ③ If the bus time window is after the green light period of the bus phase, that is At this time, the bus phase shift and non-bus phase stretch strategy group is implemented, and the theoretical shift amount of the bus phase is calculated respectively. and the maximum backward shift of the bus phase at the current moment in is the maximum green time; When the theoretical back displacement does not exceed the maximum back displacement, that is When the phase shift strategy is implemented, By evenly stretching other phases, buses are guaranteed to pass through the intersection without stopping; When the theoretical back displacement exceeds the maximum back displacement, When the public transport priority strategy is not implemented; Step S3-4: If the maximum arrival time difference of the first k1 requests exceeds the green light duration of the bus phase, Then, redundant bus priority requests are gradually deleted, so that the maximum arrival time difference of the buses in the bus priority requests to be responded to does not exceed the green light duration of the bus phase; the specific calculation method is: if Delete the last bus request k1 and update the bus request set K1 set , go to step S3-3 and recalculate.

5. A bus priority signal control system based on a mobile bus phase time window based on the method according to any one of claims 1 to 4, characterized in that: The system comprises: The first module is used to calculate the bus time window by combining bus speed fluctuations and theoretical arrival time points; The second module is used to establish a bus priority strategy based on bus phase time windows: according to the adjustment characteristics of each phase, i.e., the change of the start and end time and the phase length, the priority strategy set based on the bus time window is divided into four basic strategies: phase advance, phase delay, phase compression and phase stretch; the priority strategy set is further divided into two bus priority control strategy groups for different bus arrival situations: (1) when the bus arrival time window is before the original bus phase start time, the strategy group that implements bus phase advance and non-bus phase compression and compensation; (2) when the bus arrival time window is after the original bus phase end time, the strategy group that implements bus phase delay and non-bus phase stretch; The third module is used to establish the overall bus priority control logic: according to the characteristics of the bus when issuing a request, the two bus priority control strategy groups consisting of the above four basic strategies are combined to design the timing plan and calculate the green light time adjustment amount and start and end times of each phase to form the final bus priority control plan.

6. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

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