Detailed Description
Hereinafter, a specific embodiment of the present application will be described in detail with reference to the accompanying drawings in combination with examples. It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other.
The driving guiding method based on the digital projection lamp provided by the embodiment of the invention can be applied to the tunnel scene shown in fig. 1 and 2, fig. 1 shows a section view along the driving direction, fig. 2 is a section schematic view along the driving direction, as shown in fig. 1, a plurality of digital projection lamps are arranged above the tunnel along the driving direction, the installation positions of the digital projection lamps are not particularly limited, and fig. 2 shows a plurality of possible positions for installing the digital projection lamps, for example: the position 1 is right above the top of the tunnel, the corresponding projected pattern can be projected onto the road surface below, and for the bidirectional multilane, a corresponding digital projection lamp is arranged right above each lane; position 2 is the tunnel roof side, and the corresponding projected pattern can be projected onto the floor or the tunnel side walls (digital projection lamps, such as mounted on the tunnel roof side can be projected onto the side wall of the side where the tunnel is mounted or onto the opposite side wall). The light projection angle of the digital projection lamp can be adjusted through universal adjustment, the digital projection lamp is used for projecting various images or patterns (such as attention vehicle distance reminding, forward creep reminding, overspeed reminding, forward accident reminding, forward road maintenance reminding, forward road section reminding, rainy day road sliding reminding and the like) on the ground of a tunnel road, the projectable position of the digital projection lamp can be flexibly set, for example, the digital projection lamp can be projected on the ground, projected on a wall on the side surface of the tunnel and the like, and the digital projection lamp is used for guiding and indicating through personalized patterns to convey rich road information to a vehicle driver. Fig. 3 is a network connection topology diagram, and the plurality of digital projection lamps in fig. 1 and 2 can realize collaborative networking control, on one hand, the real-time position information of the vehicle is obtained through a sensor or a camera, on the other hand, communication interaction is carried out between the sensor and a server of a tunnel local chassis and a remote server of a cloud, and the sensor and the camera can be integrated with the digital projection lamps. The sensor can respectively position the vehicle position through ultrasonic ranging, and the camera can position the vehicle position through image recognition. The communication between digital projection lamps may be based on wired or wireless communication, wireless communication may be by using NB ⁃ IoT, zigBee, or by using DSRC (DEDICATED SHORT-Range Communications, a special wireless communication technology, mainly used for information transfer between vehicles and traffic infrastructure) wireless communication networking, the invention is described in detail below by means of specific embodiments.
Embodiment one: as shown in fig. 4, a driving guiding method based on a digital projection lamp according to an embodiment of the present invention includes:
step 401, acquiring traffic flow information in a preset time range through a sensor;
the sensor can be a camera, a ground induction coil detector, a magnetic induction detector and the like, and the vehicle flow information is acquired through the camera and the sensor. The historical data of the traffic flow, such as traffic flow data of the last month, is needed to be stored, for example, a smaller value, such as 1 hour, can be correspondingly set as a section according to the time range of the traffic flow change in consideration of the traffic flow change in peak time, can be respectively stored in two directions and in lanes in the actual storage process, meanwhile, traffic accidents, types and duration, traffic construction types and duration and the like are needed to be recorded, and in addition, the information of the average speed, acceleration and the like of the vehicles can be calculated in an auxiliary mode according to the traffic flow sampling of 3-5 vehicles to serve as auxiliary information of the traffic flow.
Step 402, inputting the acquired traffic flow information in a preset time range into a tunnel traffic flow state prediction model of a cloud server, performing multi-objective optimization on the condition that the total travel time in a tunnel is shortest and the total collision risk is the same, generating a traffic flow control strategy and issuing the traffic flow control strategy;
Step 403, generating a digital projection lamp control instruction sequence according to a traffic flow control strategy issued by the cloud server;
The road local server (a local server is arranged in a tunnel or a fixed road section, or the road local server and a server host of equipment such as ETC (electronic toll collection) can share hardware resources) and receive a traffic control strategy issued by a cloud server, and can generate and send a control instruction of a digital projection lamp carrying a digital projection lamp identifier according to the traffic control strategy and a digital projection lamp packet (corresponding to cell division in a tunnel traffic state prediction model), for example, JSON data can be generated, a key of the JSON is an IP (Internet protocol) or MAC (media access control) address of the digital projection lamp, a value part is a specific control strategy, and a value can be a suggested speed limit value, an indication mark, a guiding indication mode, switching time and the like.
And 404, the digital projection lamp projects a guide mark on the ground according to the control instruction sequence of the digital projection lamp so as to guide a driver to adjust the running state of the vehicle.
After the digital projection lamps distributed in the tunnel acquire a control instruction sequence in a wireless or wired mode, the digital projection lamps start to control the ground to conduct guiding mark projection so as to guide a driver to adjust the running state of the vehicle, for example, the speed value of the speed limit is projected to the ground, and the front accident or the construction mark can be projected when the traffic accident or the road construction happens in front, for example, different colors, flickering, voice and other prompting modes can be adopted for special traffic accidents, for example, the front congestion of the driver can be reminded by flickering, and the vehicle can run slowly or in a lane change mode.
According to the driving guiding method based on the digital projection lamp, the sensor is used for acquiring the traffic flow information in the preset time range; inputting the acquired traffic flow information in a preset time range into a tunnel traffic flow state prediction model of a cloud server, performing multi-objective optimization on the condition that the total travel time in a tunnel is shortest and the total collision risk is the same, generating a traffic flow control strategy and issuing the traffic flow control strategy; generating a digital projection lamp control instruction sequence according to a traffic flow control strategy issued by the cloud server; the digital projection lamp is used for carrying out guide mark projection on the ground according to the control instruction sequence of the digital projection lamp so as to guide a driver to adjust the running state of a vehicle, realize the personalized function of the traffic indication lamp, realize the refined dispatching of traffic, simultaneously project personalized guide marks on the ground, facilitate viewing and have strong designability in the driving process, and effectively improve the diversity of traffic dispatching modes.
Embodiment two: in order to achieve control of a single digital projection lamp, to avoid blocking the driver's view or unnecessarily wasting the power of the digital projection lamp due to improper projection time or position, the digital projection lamp needs to be controlled locally, for example, to avoid the digital projection lamp projecting directly onto the vehicle body, to reduce the number of projection lamps actually operated when no vehicle or a night vehicle is small, and to separately control the projection lamps, step 404 further includes:
404-1, judging the relative position relation between the vehicle and the digital projection lamp according to the acquired real-time position information of the vehicle;
step 404-2, adjusting the starting state or the projection angle of the digital projection lamp according to the relative position relation between the vehicle and the digital projection lamp.
Embodiment III: to accommodate driving in low light environments, in heavy fog weather, step 404 further includes:
step 404-1, judging the relative position between vehicles according to the acquired real-time position information of the vehicles;
step 404-2, adjusting the indication of the digital projection lamp according to the relative position between the vehicles.
When the relative position between vehicles and the running speed of the vehicles are larger than a preset threshold, a driver is reminded of paying attention to the distance between the vehicles and the speed of the vehicles, and the vehicles can flash to remind, so that the occurrence probability of traffic accidents can be effectively reduced in a low-illumination environment and in a foggy weather.
In addition, the digital projection lamp in front can be lighted to carry out projection indication according to the running speed and track of the vehicle, so that on one hand, the running path of the vehicle in a low-illumination environment and in a large-fog day can be guided, and on the other hand, the electric power can be saved (when the vehicle flow is sparse, the digital projection lamp needs to be lighted to a digital projection lamp with a preset distance in front of the running, and the digital projection lamp behind the running can enter a dormant state after the running for a preset time).
Embodiment four: in order to realize refined traffic scheduling in a way of integrally linking with traffic scheduling, the problem of traffic jam in a tunnel is solved, and an optimized control strategy is realized by introducing a cell transmission model CTM and matching with the division of digital projection lamps, so that a tunnel traffic flow state prediction model needs to be constructed before step 402.
In this embodiment, a cell transfer model (CTM, cell Transmission Model) is introduced, which can better simulate some traffic flow mechanical properties such as shock, queuing, and dissipation. In this embodiment, considering the situation that multiple lanes exist in the tunnel, the tunnel with length L is equally divided into N cells (the number of the digital projection lamps is N-1, N is a positive integer) by using the digital projection lamps as the marks, and the length of each cell is L/N, as shown in fig. 5, which is a schematic diagram of a part of cells in the tunnel, in which the length of one cell is equal to the equidistant length of 3 digital projection lamps, in the figureRepresenting the number of vehicles in road segment i at time step k,Representing the traffic flow of road segment i-1 to road segment i at time step k. Interval time ofAt speed for vehiclesBy time of cellThe maximum number of vehicles (cell traffic flow) that cell i can flow into cell i+1 during the t-th interval period, denoted as the transmission capability of cell i,The maximum number of vehicles (cell traffic flow) that cell i can allow cell i-1 to flow in during the t-th interval is denoted as the acceptability of cell i. The sending capability and the receiving capability of the cell i can be calculated through a traffic flow basic diagram, and the calculation formula is as follows:
Wherein,、Traffic density and speed in cell i in interval t, respectively, traffic density multiplied by speed is traffic flow,In order to achieve a blocking density,For the number of lanes in cell i,Is the traffic capacity of a single lane,Is the wave velocity. Traffic flow transferred in the intercellular t period isWherein, the method comprises the steps of, wherein,Indicating the traffic capacity of a single laneIndicating the maximum traffic capacity of a single lane and wave speedThe definition in the CTM model is the speed of traffic flow information propagation between two adjacent cells, which reflects the speed of traffic disturbances propagating upstream of the road, in m/s. Wave velocity can affect the propagation of traffic conditions between adjacent cells. For example, at high traffic densities, wave velocities may be slowed down due to the reduced vehicle-to-vehicle spacing, and traffic congestion conditions may be slowed down upstream. The wave speed is not the same as the actual vehicle running speed, but only represents the propagation speed of traffic flow information on the road. The wave speed parameter is regulated to calibrate the tunnel traffic flow state prediction model, so that the simulation result can reflect the actual traffic condition more accurately, the wave speed is an important parameter in the embodiment, the simulation effect of the model can be improved by reasonably setting the wave speed, the propagation condition of traffic flow can be predicted more accurately, and the method is used for researching the propagation of traffic jam.
Based on the description of the CTM model, due to the existing fixed cell length mode (for example, each cell length is L/N, and is a fixed length), the fixed cell length cannot truly simulate and reflect traffic conditions, and in this embodiment, the variability of the congestion point length in the tunnel is considered to perform corresponding optimization, and accordingly, the cell i supplies traffic to the cell i+1I.e. the maximum number of vehicles flowing in (cell traffic flow) is the number of vehicles stored in the length d of the second half of cell i (d is the distance the vehicle travels at free flow speed in a single simulation step), and likewise the traffic demand of cell iFor the number of vehicles remaining receivable in the length d of the first half of the cell i, both are limited by the traffic capacity of the road section, the transmitting capacity of the cell iAnd acceptance abilityThe traffic flow basic map can be used for calculation, and the optimized calculation formula is as follows:
，
，
Wherein,Is a variable cell length that is an integer multiple of the digital projection lamp spacing, and d is the distance the vehicle travels at free flow velocity within a single simulation step.
Traffic flow transferred in intercellular t periodWherein, the method comprises the steps of, wherein,For variable cell length, which is an integer multiple of the distance between digital projection lamps, d is the distance traveled by the vehicle at free flow velocity in a single simulation step, the flow density in the cell i at time t+1 can be solved by solving the formula for an LWR model (LIGHTHILL, WHITHAM AND RICHARDS model, LWR model expression satisfying the traffic flow conservation law, called LWR traffic flow partial differential equation)WhereinIn order for the time period to be a time period,For the traffic flow into the time period cell i at time t,Traffic flowing out in the t-th time for the time period cell i.
In addition, the embodiment introduces the influence factors of traffic jam in the tunnel caused by road traffic accident, reflects the probability of traffic accident in the tunnel through the vehicle collision risk function,For cell iWithin a period of time (i.e. the firstThe simulation period), the vehicle collision risk function is a speed-related function, the collision risk function of the tunnel can be obtained through linear regression model training fitting, for exampleOr (b)Wherein, the method comprises the steps of, wherein,Is the firstThe traffic speed in the cell i in each interval period can have various forms, depending on the modeling method, the coefficients 1.82 and 0.058 can change differently due to different training history data, generally model coefficients of different tunnels are different, and the tunnels are in a relatively closed environment, are less influenced by factors such as weather, light and the like, and are mainly related to the traffic speed.
In the embodiment of the invention, the multi-objective optimization of the segmented speed limit control strategy is realized by taking the shortest total travel time and the smallest total collision risk in the tunnel as targets, and the objective function is as follows
，
In this embodiment, the number of cells (according to the number of road segments of the digital projection lamp) and the control period of different speed limit control units can be adjusted according to the optimization result, so as to implement variable speed limit strategy, T and T in the tunnelFor the number of simulation cycles, N is the number of cells,For a variable cell length,For the density of cell i in the t-th simulation cycle,For the length of the simulation period,For cell iA vehicle collision risk function over a period of time. The objective function is solved by adopting NSGA-II algorithm (), and the shortest total travel time and the smallest total collision risk in the tunnel are considered. The solved speed limiting strategy can realize a speed limiting strategy based on digital projection lamp distance segmentation (cytoclasis), for example: 30 digital projection lamps are arranged on a unidirectional lane in the tunnel, the speed limit indication of the digital projection lamps 1-8 is 10km/h, the speed limit indication of the digital projection lamps 9-15 is 8km/h, the speed limit indication of the digital projection lamps 16-22 is 13km/h, the speed limit indication of the digital projection lamps 23-30 is 18km/h, the optimized tunnel internal traffic strategy is realized, meanwhile, the accident occurrence rate of rear-end collision, collision and the like is reduced, and the speed limit indication in the embodiment can be a rule forced by traffic or a recommended running speed without specific limitation.
In this embodiment, in order to make the proposed speed limit difference between adjacent cells within a reasonable range, the driver is prevented from being misled to operate due to the too fast change of the proposed speed, and the rear-end collision is easy to be caused, so that the given traffic control strategy requires additional conditions to increase the proposed speed limit difference between adjacent cells to be smaller than the preset thresholdFor example。
When the traffic speed in the tunnel is changed due to the reasons of climate, traffic control, traffic accident and the like, which belongs to the traffic speed limitation caused by the external reasons, the traffic department can display the speed limit standard at the entrance of the tunnel through broadcasting or an LED screen under the condition that the traffic speed in the free flow state of the cell i is(The traffic flow speeds of different cells i in the tunnel are consistent in the free flow state), the traffic variation density of the cells i isIn order to increase the accuracy of model simulation prediction in this embodiment, the throughput under the condition of cell i speed limit isWherein, the method comprises the steps of, wherein,，Accordingly, traffic flow transferred during inter-cell t-cycles。
Further, as a specific implementation of the method of fig. 4, in an embodiment of the present invention, there is provided a traffic guiding device based on a digital projection lamp, as shown in fig. 6, where the device includes:
an obtaining module 610, configured to obtain traffic flow information within a preset time range;
the analysis module 620 is configured to input the acquired traffic flow information within the preset time range into a tunnel traffic flow state prediction model of the cloud server, perform multi-objective optimization on the condition that the total travel time in the tunnel is shortest and the total collision risk is the same, generate a traffic flow control strategy, and issue the traffic flow control strategy;
the conversion module 630 is configured to generate a digital projection lamp control instruction sequence according to the issued traffic flow control policy;
And the execution module 640 is used for projecting the guiding mark on the ground according to the digital projection lamp control instruction sequence so as to guide the driver to adjust the running state of the vehicle.
The embodiment of the invention provides a computer device, which comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to realize the running guiding method based on the digital projection lamp, and the method comprises the following steps:
acquiring traffic flow information in a preset time range through a sensor;
Inputting the acquired traffic flow information in a preset time range into a tunnel traffic flow state prediction model of a cloud server, performing multi-objective optimization on the condition that the total travel time in a tunnel is shortest and the total collision risk is the same, generating a traffic flow control strategy and issuing the traffic flow control strategy;
generating a digital projection lamp control instruction sequence according to a traffic flow control strategy issued by the cloud server;
the digital projection lamp projects the guiding mark on the ground according to the control instruction sequence of the digital projection lamp so as to guide a driver to adjust the running state of the vehicle.
In an embodiment of the present invention, there is provided a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of:
acquiring traffic flow information in a preset time range through a sensor;
Inputting the acquired traffic flow information in a preset time range into a tunnel traffic flow state prediction model of a cloud server, performing multi-objective optimization on the condition that the total travel time in a tunnel is shortest and the total collision risk is the same, generating a traffic flow control strategy and issuing the traffic flow control strategy;
generating a digital projection lamp control instruction sequence according to a traffic flow control strategy issued by the cloud server;
the digital projection lamp projects the guiding mark on the ground according to the control instruction sequence of the digital projection lamp so as to guide a driver to adjust the running state of the vehicle.
It should be noted that, in the foregoing embodiments, the principle and implementation steps of the embodiments of the present invention are only described by using the tunnel distance, and the actual traffic application scenario is not limited in particular, for example, the technical solution of the present invention may also be applied to a common channel, a bridge, etc., and with respect to functions or steps that can be implemented by a computer readable storage medium or a computer device, reference may be correspondingly made to the foregoing method embodiments, and the description on the server side and the client side will not be described one by one for avoiding repetition.
Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (SYNCHLINK) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-described division of the functional units and modules is illustrated, and in practical application, the above-described functional distribution may be performed by different functional units and modules according to needs, i.e. the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-described functions.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and are intended to be included in the scope of the present invention.