A method for calculating the water film spatter range of a road surface of a highway

Abstract

The application discloses a kind of road surface water film splashing range calculation method for highway, step 1: the existence of water film in road surface is judged, it is divided into A class persistence road surface water film, B class stagnation road surface water film, and the center control module of water film warning system is used to judge specific type;Step 2: detect whether there is vehicle in the lateral lane of the vehicle in real time, and the speed information of the vehicle in the lateral lane is collected, compared with the position information of the detected vehicle and the tire information of the detected vehicle;Step 3: according to the type of water film detected, specific water film thickness information is obtained;Step 4: establish road surface water film splashing water mist model, the model of water film splashing water mist is established by the information obtained, and it is determined whether it will affect the vehicle driving.The application takes the road surface water in rainy day as research object, establishes the influence model of road surface splashing water mist, effectively guarantees the driving safety of road driver in rainy day.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of traffic safety, and particularly relates to a road surface water film splashing range calculation method for expressways. BACKGROUND

[0002] Safe driving of vehicles is an event that drivers, road safety supervision departments and governments are jointly concerned about. However, there are some uncontrollable factors that affect the safe driving of vehicles, and the strange and variable weather factors have an important influence on the safe driving of vehicles. The present application takes the influence of road surface water on the safe driving of vehicles as the breakthrough point, and considers the characteristics of high speed of vehicles on expressways and high degree of influence after accidents, therefore, the present application focuses on the problem of safe driving of vehicles on expressways under the influence of road surface water. In actual situations, due to the increase of rainfall in rainy weather and the emergence of flatness of expressways, a thin layer of road surface water film will appear on the road surface of the expressway. Such water film has a certain influence on the safe driving of vehicles, and the generation of road surface water film is also caused by some other reasons. The road surface water film will cause abnormal driving interference such as side slip to the passing vehicles, and when a vehicle passes through the road surface water film, a layer of splashed water mist will appear at the side rear of the driving vehicle due to the high-speed contact of the wheels with the road surface water film, which will cause a certain visual obstruction to the rear of the water film generation, thereby causing certain traffic accidents and causing personal and property safety losses to vehicles and drivers.

[0003] In the existing related research, multiple from the device of the vehicle itself, from the improvement or setting of the tire material and pattern of the vehicle or the mechanical device that can isolate the water mist to block the water mist after splashing. However, in the above two schemes, there will be a situation that the water mist blocking rate is not high and the protection effect is not good due to complex situation in some road surface conditions, and at the same time, the above facilities will affect the driving performance of the vehicle due to the mechanical improvement of the vehicle, and even the setting will become a potential hidden danger factor in other road safety aspects. The existing water mist warning device research is less, and the warning method and process are poor in scientificity and simple in process. Multiple for the water film information under the condition that the water film appears on the road surface, but there is no detailed discussion on how to safely warn the vehicle after receiving the water mist detection information, which cannot effectively guarantee the personal and property safety of road drivers.

[0004] How to measure the water mist information and calculate the influence of the water mist on road drivers has become a technical problem to be solved. SUMMARY

[0005] The present application aims to provide a road surface water film splashing range calculation method for highways, which can solve the problems in the background art by calculating the water film information splashed by vehicles based on the collected information of the water film on the road surface and the information of the vehicles that have passed through the water film, and determining the final water mist influence warning through the water film influence range, etc.

[0006] To achieve the above object, the present application provides the following technical solutions.

[0007] A road surface water film splashing range calculation method for highways comprises the following steps:

[0008] Step 1: Determine the existence of water film on the road surface, divide it into A-type persistent road surface water film and B-type stagnant road surface water film, and use the central control module of the water film warning system to determine the specific type; the A-type persistent road surface water film is defined as the case where persistent water film appears on the road surface due to rainfall weather; the B-type stagnant road surface water film is defined as the case where persistent water film appears on the road surface due to non-rainfall weather;

[0009] Step 2: Detect whether there is a vehicle in the lateral lane of the vehicle in real time, and collect the speed information of the vehicle in the lateral lane, the position information compared with the detected vehicle, and the tire information of the detected vehicle;

[0010] Step 3: Obtain the specific water film thickness information according to the detected water film type;

[0011] Step 4: Establish a road surface water film splashing water mist model, establish the model of water film splashing water mist through the obtained information, and determine whether it will affect the driving vehicle.

[0012] Further schemes of the present application are as follows:

[0013] Step 1.1: During the driving of the vehicle, first obtain the geographical position information of the location of the vehicle, link with the weather network system of the region, and detect whether there is rainfall within a certain time interval of the position information of the vehicle; the road surface water film can be produced before rainfall, after rainfall, and in some special water accumulation sections; different starting modes and determination modes are carried out based on the three states of rainfall having occurred, rainfall being in progress, and special water accumulation sections.

[0014] Step 1.2: When the determination result is that the rainfall has occurred, the B type of the water film detection system of the road surface water film detection mode is started; when the determination result is that the rainfall is occurring, the A type of the water film detection system of the road surface water film detection mode is started; in the special water accumulation road section, the road surface water film accumulation caused by other reasons is started by the manual method, and since the road surface water film accumulation in this case is similar to the road surface water film accumulation caused by the retention, the B type of the water film detection system of the road surface water film detection mode is also started.

[0015] A further scheme of the present application is that in step 2, the vehicle real-time detection vehicle lateral lane whether there is a vehicle, using the vehicle information acquisition and calculation module to collect the speed information V L (km / h) of the detected vehicle, the position information (X L0 , Y L0 ) of the detected vehicle compared with the detection vehicle, the tire information Q L =(D L , B L , C L ) of the detected vehicle, wherein D L represents the tire width (unit: cm), B L tire groove depth (unit: mm), and the position influence determination formula of the detection vehicle and the detected vehicle;

[0016] A further scheme of the present application is that step 2 includes the following process:

[0017] Step 2.1: detecting the existence of the detected vehicle, the device is mainly used to determine whether the detected vehicle exists, when the detection result is that there is, the speed information V L (km / h) of the detected vehicle, the position information (X L0 , Y L0 ) of the detected vehicle, and the tire information Q L =(D L , B L , C L ) of the detected vehicle are obtained;

[0018] Step 2.2: in the process of obtaining the speed of the detected vehicle, the speed of the detected vehicle is obtained through the vehicle information acquisition and calculation module, and the speed of the detected vehicle is recorded as V L (km / h); in the process of recording the position information of the detected vehicle, a rectangular coordinate system is established for convenience of calculation and position recording; the driving direction of the detection vehicle is taken as the positive direction of the Y axis, and the vertical direction of the driving direction of the detection vehicle is taken as the positive direction of the X axis, and the intersection of the above X axis and Y axis is taken as the coordinate origin (unit: m); the coordinate system is taken as the reference system, the position coordinates of the detected vehicle are recorded, and the position information of the detected vehicle is recorded as (XL0 , Y L0 ), wherein X L0 represents the position information of the detected vehicle about the X-axis of the rectangular coordinate system, Y L0 represents the position information of the detected vehicle about the Y-axis of the rectangular coordinate system;

[0019] Step 2.3: Obtain the tire information Q L = (D L , B L , C L ) of the detected vehicle. Among the influencing factors of vehicle water mist generation, the tire characteristics and area information of the vehicle will affect water mist generation. The wheel width, wheel pattern and groove depth of the detected vehicle wheel, and the existence of water mist shielding are mainly selected. Compile the above detected information Q L = (D L , B L , C L ), wherein Q L represents the tire information set of the detected vehicle, D L represents the tire width (unit: cm), B L represents the tire groove depth (unit: mm), and C L represents the existence of water mist shielding. The water mist shielding mainly includes the rear water mist shielding device and the side rear water mist shielding.

[0020] Step 2.3: According to the position information (X L0 , Y L0 ) of the detected vehicle obtained in step 2, record the speed information V L (unit: km / h) of the detected vehicle and the speed information V J (unit: km / h) of the detected vehicle. From the left and right side view angles of the detected vehicle as the starting point, record the position of the detected vehicle appearing in the view angle range of the detected vehicle as the position influence of the detected vehicle and the detected vehicle. The left side view angle of the vehicle is set to 35°, and the right side view angle is set to 60°. In actual situations, the vehicle is in continuous position movement, so the position information of the detected vehicle and the position information of the detected vehicle are two curves moving according to a certain trajectory. The position information trajectory curve of the detected vehicle is set to Y Jt = F(X Jt );

[0021] wherein F(X Jt ) represents the trajectory curve equation of the detected vehicle;

[0022] Y Jt represents the Y-axis coordinate value of the detected vehicle about time t in the established coordinate system;

[0023] XJt represents the X-axis coordinate value of the detected vehicle in the established coordinate system with respect to time t;

[0024] The position information trajectory curve of the detected vehicle is set as Y Lt = F(X Lt );

[0025] Wherein F(X Lt ) represents the trajectory curve equation of the detected vehicle;

[0026] Y Lt represents the Y-axis coordinate value of the detected vehicle in the established coordinate system with respect to time t;

[0027] X Lt represents the X-axis coordinate value of the detected vehicle in the established coordinate system with respect to time t;

[0028] The position information (X Jt , Y Jt ) of the detected vehicle and the position information (Y Lt , X Lt ) of the detected vehicle are determined, and the field of view range area of the detected vehicle is set as S Lt (unit: m 2 );

[0029] The position influence determination formula of the detected vehicle and the detected vehicle is established as follows:

[0030]

[0031] Wherein p (X,Y) represents the position influence formula of the detected vehicle and the detected vehicle;

[0032] represents that the position of the detected vehicle and the detected vehicle will have an influence on the detected vehicle appearing in the field of view range area S Lt of the detected vehicle; represents that the position of the detected vehicle and the detected vehicle will not have an influence on the detected vehicle not appearing in the field of view range area S Lt of the detected vehicle.

[0033] A further scheme of the present application is that in step 3, according to the water film detection mode detected in step 1, the specific water film detection process is carried out, mainly through the water film information acquisition and detection module to measure the basic information of the water film, and different detection processes are carried out for the A type persistent road surface water film detection mode and the B type stagnant road surface water film detection mode;

[0034] Wherein step 3 includes the following processes:

[0035] Step 3.1: A type of persistent road water film detection mode, A type of road water film, is a layer of water film on the surface of the highway due to continuous rainfall, but due to the change of rainfall, the basic information of the road water film will be affected, so it is necessary to detect the road water film at a certain period and use the data obtained by detection;

[0036] In the process of A type of persistent road water film detection, first measure the thickness of the road water film, and record the thickness of the road water film as d Ah (unit: mm), in the specific operation process, because the road water film is persistent on the surface of the highway, without considering the road slope and road flatness, using the propagation speed of light through different media, water depth = time difference × light speed / 2;

[0037] The specific formula is as follows:

[0038]

[0039] Where d Ah represents the thickness of A type of water film (unit: mm);

[0040] Δt represents the time difference between emitting light and receiving light (unit: s);

[0041] v l represents the propagation speed of the laser used (unit: mm / s);

[0042] Considering that in the actual persistent rainfall, the depth of the road water film will change with the change of rainfall, so it is necessary to detect the road water film in real time, because the road water film needs to contact with the driving vehicle to cause the water mist affecting driving, so when the vehicle appears in step 2, the thickness of the road water film will be measured;

[0043] Step 3.2: B type of persistent road water film detection mode, B type of road water film is mostly generated after rainfall due to the unevenness of the road, which leads to the generation of road water film, or other reasons leading to the phenomenon of part of the road water film appearing in the road; In the process of B type of persistent road water film detection, first measure the position information and area information of the road water film, and then measure the thickness information of the water film;

[0044] In the process of B type of persistent road water film detection, first use a light source emitting device with light source, when scanning the road water, the image processing display of the light source emitting device will appear different from the image result without water, and then the length of the water film will be detected;

[0045] When the basic information of the water film is detected, when there is no road surface water, the light HG is directly absorbed by the road surface, when the road surface water appears, the path change of the light is caused due to the reflection of the light, the physical image of the detected water film information is established by the physical change, the principle diagram of the device can be simplified as a physical concept model diagram, DE in the physical concept diagram represents the thickness of the water film, is an unknown quantity, and the lengths of other line segments are consistent, so the application establishes a B-type standing water film thickness information calculation formula:

[0046]

[0047] Wherein GZ represents the length (unit: mm) of the physical concept of GZ in the diagram;

[0048] DE represents the length (unit: mm) of the physical concept of DE in the diagram;

[0049] sinB represents the sin value of angle HBZ in the diagram;

[0050] sinZ represents the sin value of angle Z in the diagram,

[0051] In practical significance, DE represents the thickness of the water film (unit: mm), considering the non-uniformity of the thickness of the road surface water film, the water film thickness is measured multiple times, the thickness of the water film is usually not a constant value, and there is a certain water level difference in the same piece of road surface water, so the center of gravity of the irregular figure is established by using the water film contour diagram of the water film detection device, the center of gravity is taken as the center point, the split line of the irregular figure is established, and the water film thickness calculation method of the upper diagram is used at both ends of the split line; therefore, all the split line segments are marked, and the final water film thickness calculation formula is obtained:

[0052]

[0053] A further scheme of the application is that step 4 establishes a water film splashing water mist model according to the water film thickness information obtained in steps 2 and 3, establishes a water film splashing water mist model by the obtained information, and determines whether the water film splashing water mist model will affect the driving vehicle;

[0054] The water film splashing influence model is established by the vehicle position information, the road surface water film thickness and the road surface water film length calculated by the above steps, in the specific water film splashing influence model, whether the water mist height, the water mist width and the water mist visibility will affect the rear vehicle are determined;

[0055] Step 4.1: first, establish a water mist height influence model:

[0056]

[0057] where H represents the height of the splashing water mist (unit: cm);

[0058] K represents the coefficient of the road condition and the vehicle tire;

[0059] V l represents the driving speed of the vehicle (unit: m / s);

[0060] g represents the acceleration of gravity;

[0061] Step 4.2: Secondly, the water mist visibility influence model is established to convert the visibility of the water mist into the mass of water contained per cubic meter, which is defined as ML(unit: kg / m 3 ), and the water mist generated by the vehicle driving is generally divided into side water mist ML si (unit: kg / m 3 ) and rear water mist ML be (unit: kg / m 3 ), so the water mist influence model caused by the vehicle is:

[0062] ML = ML si + ML be ;

[0063] Through fluid mechanics and research, it is found that the maximum water quantity of the side water mist and the rear water mist visibility water mist is:

[0064] SL i = V l · D · d Al · γ;

[0065] where SL i represents the maximum water quantity (unit: kg / s), i can be taken (si, be) (si represents the side water mist, and be represents the rear water mist);

[0066] V l represents the truck speed (unit: m / s);

[0067] D represents the tire width (unit: m);

[0068] d Al represents the water film thickness (unit: m);

[0069] γ represents the density of water;

[0070] Considering the groove problem of the vehicle tire, the above formula is expanded about the depth of the actual contact water film of the tire, so the above model is corrected according to the proportion of the tire groove;

[0071] First, the side water spray is corrected and defined as SL si+1 SL

[0072] SL si+1 = (1 - a) · V l · D · g · (d Al - k · h z - (1 - k) · h g ) ;

[0073] SL be+1 = a · V l · D · g · (d Al - k · h z - (1 - k) · h g ) ;

[0074] wherein SL si+1 represents the corrected side water spray (unit: kg / s) ;

[0075] wherein SL be+1 represents the corrected rear water spray (unit: kg / s) ;

[0076] a represents a coefficient of water fluid mechanics;

[0077] V l represents the truck speed (unit: mm / s) ;

[0078] D represents the tire width (unit: mm) ;

[0079] d Al represents the water film thickness (unit: mm) ;

[0080] g represents the density of water;

[0081] k represents the ratio of the non-groove in the tire;

[0082] h z represents the water film depth per tire rotation (unit: mm) ;

[0083] h g represents the water depth per tire surface (unit: mm) ;

[0084] Finally, the model of the visibility and the maximum water spray is calculated:

[0085] ML be = (2.67 · 10 -5 · V l - 4.71 · 10 -4 ) SL be+1 ;

[0086] ML si= (1.65 · 10 -5 · V l - 3.99 · 10 -4 ) SL si+1 ;

[0087] side water mist ML si (unit: kg / m 3 ) and rear water mist ML be (unit: kg / m 3 ),

[0088] The visibility results of the water mist are classified into 5 levels, wherein the visibility index of level 1 is 0.000-0.005 kg / m 3 ; the visibility index of level 2 is 0.005-0.010 kg / m 3 ; the visibility index of level 3 is 0.010-0.015 kg / m 3 ; the visibility index of level 4 is 0.015-0.020 kg / m 3 ; and the visibility index of level 5 is 0.020 kg / m 3 and above;

[0089] Among them, level 2 and above are the water mist visibility that will affect the driving of the driver;

[0090] The water mist height, water mist visibility, and vehicle position information model of the vehicle are combined to establish a water mist influence model as follows:

[0091]

[0092] wherein P represents the water mist influence model;

[0093] p h represents the water mist height influence determination formula;

[0094] H represents the water mist height (unit: m);

[0095] H C represents the height of the front side window of the detection vehicle (unit: m);

[0096] p ML represents the water mist visibility determination formula;

[0097] p (X,Y) represents the position influence determination formula of the detection vehicle and the detected vehicle;

[0098] In the above determination formula, when the value of p is 1, it means that this form of influence may occur, and when the final influence model result is 3, it means that the detection vehicle will be affected.

[0099] The beneficial effects of the present application are:

[0100] Compared with the prior art, the present application firstly studies the water mist problem of the expressway, fills the research gap in the related aspects, and uses the refraction principle of light to detect and collect information on the water film on the road surface, which is simple in cost and high in effect. At the same time, it makes up for the existing related research which solves the water mist problem of the vehicle from the physical device aspect, but the influence of water mist is mostly on the rear vehicle, so the present application studies the influence of water mist from the rear vehicle, which can effectively reduce the influence of water mist and make the device obtain a certain use rate and ensure the safety of road drivers. BRIEF DESCRIPTION OF DRAWINGS

[0101] Figure 1 The water mist warning system of the present application.

[0102] Figure 2 The physical model diagram of the water mist detection of the present application.

[0103] Figure 3 The water mist influence range diagram of the present application. DETAILED DESCRIPTION

[0104] The present application will be further illustrated below in combination with the drawings and specific embodiments.

[0105] Reference Figure 1 The present application discloses a road surface water film splash range calculation method for an expressway, and the specific implementation scheme is as follows:

[0106] Step 1: judging the existence type of the water film on the road surface, the present application divides the existence of the water film into two types, A type of persistent road surface water film, which is defined by the present application as the case that the road surface appears persistent water film due to rainfall weather; and B type of stagnant road surface water film, which is defined in the present application as the case that the road surface appears persistent water film due to non-rainfall weather. And a water film type detection module is used to judge the specific type.

[0107] The step 1 includes the following processes:

[0108] Step 1.1: during the driving process of the vehicle, first acquire the geographical position information of the location of the vehicle, and link with the weather network system of the region to detect whether the position information of the vehicle has rainfall within a certain time interval. Since the road surface water film can be generated before rainfall, after rainfall and in some special water accumulation road sections, different starting modes and determination modes are adopted based on the three states of rainfall having occurred, rainfall being in progress and special water accumulation road sections.

[0109] Step 1.2: When the determination result is that the rainfall has occurred, the B type of the water film detection system of the road water film detection mode of the water film detection system is started; when the determination result is that the rainfall is occurring, the A type of the water film detection system of the road water film detection mode of the water film detection system is started; in the special water accumulation road section, the road water film accumulation caused by other reasons is artificially enabled in the application, and the B type of the water film detection system of the road water film detection mode is also used because the road water film accumulation in this case is similar to the road water film accumulation caused by the retention.

[0110] Step 2: Detecting whether there is a vehicle in the lateral lane of the vehicle in real time, using the vehicle information acquisition and calculation module to acquire the speed information V L (km / h) of the detected vehicle in the lateral lane, the position information (X L0 , Y L0 ) of the detected vehicle compared with the detection vehicle, and the tire information Q L =(D L , B L , C L ) of the detected vehicle, wherein D L represents the tire width (unit: cm), B L represents the tire groove depth (unit: mm), and the position influence determination formula of the detection vehicle and the detected vehicle.

[0111] Step (2) includes the following processes:

[0112] Step 2.1: Detecting the existence of the detected vehicle, which is mainly used to determine whether the detected vehicle exists, and when the detection result is that the detected vehicle exists, acquiring the speed information V L (km / h) of the detected vehicle, the position information (X L0 , Y L0 ) of the detected vehicle, and the tire information Q L =(D L , B L , C L ) of the detected vehicle.

[0113] Step 2.2: In the process of acquiring the speed of the detected vehicle, the speed of the detected vehicle is acquired through the vehicle information acquisition and calculation module, and the speed of the detected vehicle is recorded as V L (km / h). In the process of recording the position information of the detected vehicle, a rectangular coordinate system is established for convenience of calculation and position recording. The driving direction of the detection vehicle is taken as the positive direction of the Y axis, the vertical direction of the driving direction of the detection vehicle is taken as the positive direction of the X axis, and the intersection of the above X axis and Y axis is taken as the coordinate origin (unit: m). The coordinate system is taken as the reference system, the position coordinates of the detected vehicle are recorded, and the position information of the detected vehicle is recorded as (X L0 , YL0 ), where X L0 This represents the position information of the detected vehicle about the X-axis of a Cartesian coordinate system, and the Y-axis represents the position information of the vehicle about the X-axis. L0 This indicates the position information of the detected vehicle about the Y-axis of the Cartesian coordinate system.

[0114] Step 2.3: Obtain the tire information Q of the vehicle being inspected. L =(D L B L C L Among the factors influencing water mist generation on vehicles, tire characteristics and area can significantly impact mist formation. Based on literature review, this invention primarily focuses on the wheel width, tread pattern and groove depth of the tested vehicle, as well as the presence of water mist obstructions. This detected information is then compiled into Q... L =(D L B L C L ), where Q L D represents the set of tire information for the vehicle being inspected. L Indicates tire width (unit: cm), B L Tire groove depth (unit: mm), C L The presence of water mist blocking objects is indicated. In this invention, water mist blocking objects are mainly divided into rear water mist blocking devices and side-rear water mist blocking devices.

[0115] Step 2.4: Based on the location information (X) of the vehicle being detected obtained in step (2), L0 Y L0 It also records the speed information V of the detected vehicle. L (Unit: km / h) and the speed information of the detected vehicle V J (Unit: km / h). This invention takes the left and right viewpoints of the detected vehicle as its starting point, recording the position of the detected vehicle within the field of view of the detected vehicle as the positional influence between the two vehicles. This invention sets the left viewpoint of the vehicle to 35° and the right viewpoint to 60°. In reality, vehicles are in continuous positional movement, so the position information of the detected vehicle and the position information of the detected vehicle are two curves moving along a certain trajectory. The trajectory curve of the detected vehicle's position information is set as Y... Jt =F(X) Jt ).

[0116] Where F(X) Jt ) represents the trajectory curve equation of the detected vehicle.

[0117] Y Jt This represents the Y-axis coordinate of the detected vehicle relative to time t within the established coordinate system.

[0118] X Jt represents the X-axis coordinate value of the detected vehicle in the established coordinate system with respect to time t.

[0119] The position information trajectory curve of the detected vehicle is set to Y Lt = F(X Lt ).

[0120] wherein F(X Lt ) represents the trajectory curve equation of the detected vehicle.

[0121] Y Lt represents the Y-axis coordinate value of the detected vehicle in the established coordinate system with respect to time t.

[0122] X Lt represents the X-axis coordinate value of the detected vehicle in the established coordinate system with respect to time t.

[0123] The position information (X Jt , Y Jt ) of the detected vehicle and the position information (Y Lt , X Lt ) of the detected vehicle are determined, and the field of view range area of the detected vehicle is set to S Lt (unit: m 2 ).

[0124] The following position influence determination formula of the detected vehicle and the detected vehicle is established:

[0125]

[0126] wherein p (X,Y) represents the position influence formula of the detected vehicle and the detected vehicle;

[0127] represents that the position of the detected vehicle and the detected vehicle will have an influence on the detected vehicle appearing in the field of view range area S Lt of the detected vehicle; represents that the position of the detected vehicle and the detected vehicle will not have an influence on the detected vehicle not appearing in the field of view range area S Lt of the detected vehicle.

[0128] Step 3: According to the water film detection mode detected in step 1, the specific water film detection process is carried out, mainly through the water film information acquisition and detection module to measure the basic information of the water film, and different detection processes are carried out for the A type persistent road water film detection mode and the B type stagnant road water film detection mode.

[0129] wherein step 3 includes the following processes:

[0130] Step 3.1: A type of persistent road surface water film detection mode: A type of road surface water film is a layer of water film that appears on the surface of the highway due to continuous rainfall, but due to the change of rainfall, the basic information of the road surface water film will be affected, so it is necessary to detect the road surface water film at a certain period. And use the data obtained by detection.

[0131] In the process of A type of persistent road surface water film detection, first measure the thickness of the road surface water film, and record the thickness of the road surface water film as d Ah (unit: mm), in the specific operation process, because the road surface water film is persistent on the surface of the highway, without considering the road slope and road flatness, using the propagation speed of light through different media, water depth = time difference x light speed / 2.

[0132] The specific formula is as follows:

[0133]

[0134] Where d Ah represents the thickness of A type of water film (unit: mm);

[0135] Δt represents the time difference between emitting light and receiving light (unit: s);

[0136] v l represents the propagation speed of the laser used (unit: mm / s).

[0137] Considering that in the actual persistent rainfall, the depth of the road surface water film will change with the change of rainfall, so it is necessary to detect the road surface water film in real time, because the road surface water film needs to contact with the driving vehicle to cause the water mist that affects driving, so when the vehicle appears in step 2, the thickness of the road surface water film is measured.

[0138] Step 3.2: B type of persistent road surface water film detection mode: B type of road surface water film is mostly generated after rainfall due to the unevenness of the road surface, which leads to the generation of road surface water film, or other reasons cause part of the road surface water film phenomenon. In the process of B type of persistent road surface water film detection, first measure the position information and area information of the road surface water film, and then measure the thickness information of the water film.

[0139] In the process of B type of persistent road surface water film detection, first use a light source emitting device with a light source, when scanning the road surface water, the image processing display of the light source emitting device will appear different from the image result without water, and then the length of the water film is detected.

[0140] When the basic information of the water film is detected, when there is no road surface water, the light HG is directly absorbed by the road surface, and when the road surface water appears, the path change of the light is caused due to the reflection of the light. The physical image establishment image solution method is combined with the position information of the real-time water film detector to establish the water film information detected. The principle diagram of the device can be simplified as shown in the physical concept model diagram Figure 2 DE represents the thickness of the water film (unit: mm), and the non-uniformity of the thickness of the road surface water film is considered. Therefore, the water film thickness is measured multiple times. The thickness of the water film is usually not a constant value. There is a certain water level difference in the same piece of road surface water. Therefore, first, the water film contour diagram of the water film detection device is used to establish the center of gravity of the irregular figure. The center of gravity is taken as the center point. The split line of the irregular figure is established. The water film thickness calculation method of the upper figure is used for the two ends of the split line. Therefore, all the split line segments are marked to obtain the final water film thickness calculation formula:

[0141]

[0142] GZ represents the length of GZ in the physical concept of the figure (unit: mm);

[0143] DE represents the length of DE in the physical concept of the figure (unit: mm);

[0144] sinB represents the sin value of angle HBZ in the physical concept of the figure;

[0145] sinZ represents the sin value of angle Z in the physical concept of the figure.

[0146] In practical significance, DE represents the thickness of the water film (unit: mm). Considering the non-uniformity of the thickness of the road surface water film, the water film thickness is measured multiple times. The thickness of the water film is usually not a constant value. There is a certain water level difference in the same piece of road surface water. Therefore, first, the water film contour diagram of the water film detection device is used to establish the center of gravity of the irregular figure. The center of gravity is taken as the center point. The split line of the irregular figure is established. The water film thickness calculation method of the upper figure is used for the two ends of the split line. Therefore, all the split line segments are marked to obtain the final water film thickness calculation formula:

[0147]

[0148] Step 4: According to the water film splash water mist model established in steps 2 and 3, the model of the water film splash water mist is established through the obtained information, and it is determined whether it will affect the driving vehicle.

[0149] The water film splash influence model is established by the vehicle position information, the road surface water film thickness, and the road surface water film length calculated by the above steps. In the specific water film splash influence model, whether it will affect the rear vehicle is mainly determined according to the water mist height, the water mist width, and the water mist visibility.

[0150] Step 4.1: First, the water mist height influence model is established:

[0151]

[0152] Where H represents the height of the splashing water mist (unit: cm);

[0153] K represents the coefficient of road surface condition and vehicle tire condition;

[0154] V l Indicates the vehicle's speed (unit: m / s);

[0155] g represents the acceleration due to gravity.

[0156] Step 4.2: Next, establish a water mist visibility impact model, converting the visibility of water mist into the mass of water contained per cubic meter, defined as ML (unit: kg / m³). 3 Meanwhile, the water mist generated by vehicle movement is generally divided into lateral water mist (ML). si (Unit: kg / m³) 3 ) and the water mist behind ML be (Unit: kg / m³) 3 ).

[0157] like Figure 3 The diagram shown illustrates the effect of water mist from a vehicle. The model for the water mist effect caused by a vehicle is as follows:

[0158] ML = ML si +ML be ;

[0159] Fluid mechanics research has revealed that the maximum water volume for lateral and rear water mist visibility is:

[0160] SL i =V l ·D·d Al ·γ;

[0161] SL i Indicates the maximum water consumption (unit: kg / s), where i can be (si, be) (si represents side water mist, be represents rear water mist);

[0162] V l Indicates truck speed (unit: m / s);

[0163] D indicates the tire width (unit: m);

[0164] d Al Indicates the thickness of the water film (unit: m);

[0165] γ represents the density of water.

[0166] Considering the groove problem of the vehicle tire, the formula is expanded on the depth of the actual contact water film of the tire, and the model is corrected according to the proportion of the tire groove

[0167] Firstly, the side water mist is corrected and defined as SL si+1 The corrected side water amount is represented as:

[0168] SL si+1 =(1-α)·V l ·D·γ·(d Al -k·h z -(1-k)·h g );

[0169] SL be+1 =α·V l ·D·γ·(d Al -k·h z -(1-k)·h g );

[0170] Wherein SL si+1 represents the corrected side water amount (unit: kg / s);

[0171] Wherein SL be+1 represents the corrected rear water amount (unit: kg / s);

[0172] α represents the coefficient of water fluid mechanics;

[0173] V l represents the truck speed (unit: mm / s);

[0174] D represents the tire width (unit: mm);

[0175] d Al represents the water film thickness (unit: mm);

[0176] γ represents the density of water;

[0177] k represents the ratio of non-groove in the tire;

[0178] h z represents the water film depth of each tire rotation (unit: mm);

[0179] h g represents the water depth of each tire surface (unit: mm)。

[0180] Finally, the model of the visibility and the maximum water amount is calculated:

[0181] ML be =(2.67·10 -5 ·V l-4.71·10 -4 )SL be+1 ;

[0182] ML si =(1.65·10 -5 ·V l -3.99·10 -4 )SL si+1 ;

[0183] side water mist ML si (unit: kg / m 3 ) and rear water mist ML be (unit: kg / m 3 ),

[0184] The visibility results of the water mist are classified into grades, and the results are divided into:

[0185]

[0186] The grades 2 and above are the water mist visibility that will affect the driving of the driver, and the water mist height, water mist visibility, and vehicle position information model are combined to establish a water mist influence model as follows:

[0187]

[0188] wherein P represents the water mist influence model;

[0189] p h represents the water mist height influence determination formula;

[0190] H represents the water mist height (unit: m);

[0191] H C represents the height of the front side window of the detection vehicle (unit: m);

[0192] p ML represents the water mist visibility determination formula;

[0193] p (X,Y) represents the position influence determination formula of the detection vehicle and the detected vehicle;

[0194] In the above determination formula, when the value of p is 1, it means that this form of influence may occur, and when the final influence model result is 3, it means that the detection vehicle will be affected.

[0195] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent transformation or modification made according to the spirit and essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A road surface water film splash range calculation method for an expressway, characterized by, Comprising the following steps: Step 1: judging the existence of water film in the road surface, dividing it into A type persistent road surface water film and B type stagnant road surface water film, and using the central control module of the water film warning system to judge the specific type; A type persistent road surface water film is defined as the case that persistent water film appears on the road surface due to rainfall weather; B type stagnant road surface water film is defined as the case that persistent water film appears on the road surface due to non-rainfall weather; Step 2: detecting whether there is a vehicle in the lateral lane of the vehicle in real time, and collecting the speed information of the vehicle in the lateral lane, the position information compared with the detected vehicle and the tire information of the detected vehicle; Step 3: acquiring specific water film thickness information according to the detected water film type; Step 4: establishing a road surface water film splashing water mist model, establishing a water film splashing water mist model through the acquired information, and determining whether it will affect the driving vehicle; Wherein step 4 establishes a road surface water film splashing water mist model according to steps 2 and 3, establishes a water film splashing water mist model through the acquired information, and determines whether it will affect the driving vehicle; The vehicle position information, road surface water film thickness and road surface water film length calculated by the above steps are used to establish a water film splashing influence model, in which the water mist height, water mist width and water mist visibility are mainly used to determine whether it will affect the rear vehicle; Step 4.1: first establish a water mist height influence model: ； wherein Hsp represents the height of the splashed water mist in cm; a coefficient representative of the road surface condition and of the vehicle tires; V represents the running speed of the vehicle, unit: m / s; g represents the gravitational acceleration; Step 4.2: The second step is to establish the water mist visibility influence model, which converts the visibility of water mist into the mass of water contained per cubic meter, which is defined as , unit: kg / m 3 At the same time, the water mist generated by the vehicle driving is usually divided into side water mist , unit: kg / m 3 and rear water mist , unit: kg / m 3 Therefore, the water mist influence model caused by the vehicle is: ； Through fluid mechanics and research, it is found that the maximum water volume of side water mist and rear water mist visibility water mist is: ； wherein represents the maximum water usage, in kg / s, i takes si or be, si represents side water spray, be represents back water spray; Vtruck represents the truck speed, in m / s; represents the tire width, in m; represents the water film thickness, in m; Indicates the density of water; Considering the problem of vehicle tire grooves, the above formula is expanded to the depth of the actual contact of the water film with the tire, so the above model is corrected according to the proportion of the tire grooves; First, the side water spray is modified and defined as represents the modified side water usage: ； ； wherein represents the corrected side water amount, unit: kg / s; wherein represents the corrected rear water amount, unit: kg / s; represents a coefficient of water fluid dynamics; represents the truck speed, in mm / s; represents the tire width, in mm; represents the water film thickness in mm; denotes the density of water; represents the ratio of the non-groove portion in the tire; represents the water film depth per tire revolution, in mm; represents the water depth at each point of the tire surface, in mm; Finally, the model of visibility and maximum water volume is calculated: ； ； Side water mist , unit: kg / m 3 , unit: kg / m , unit: kg / m 3 , The results for the visibility of the water mist were classified into five classes, where class 1 had a visibility index of 0.000 - 0.005 kg / m 3 , class 2 had a visibility index of 0.005 - 0.010 kg / m 3 , class 3 had a visibility index of 0.010 - 0.015 kg / m 3 , class 4 had a visibility index of 0.015 - 0.020 kg / m 3 , and class 5 had a visibility index of 0.020 kg / m 3 and above. Wherein level 2 and above are water mist visibility that will affect the driver; The water mist height, water mist visibility and vehicle position information model of the vehicle are combined to establish a water mist influence model as follows: ； wherein represents a water mist influence model; represents a water mist high influence determination formula; represents the height of the water mist, in m; represents the height of the front side window of the detected vehicle, in m; represents a water mist visibility determination formula; represents a position influence determination formula for detecting a vehicle and a detected vehicle; In the above determination formula, when the p value is 1, it means that this form of influence may occur, and when the final influence model result is 3, it means that it will affect the detected vehicle.

2. The method for calculating a water film spatter range of a road surface of a highway according to claim 1, wherein The step 1 includes the following processes: Step 1.1: during the driving of the vehicle, first acquire the geographical position information of the place where the vehicle is located, and link with the weather network system of the area to detect whether there is rainfall in a certain time interval; Because road surface water film can be produced before rainfall, after rainfall and in some special water accumulation sections; Based on the three states of rainfall has occurred, rainfall is occurring and special water accumulation section, different starting modes and determination modes are carried out respectively; Step 1.2: When the determination result is that the rainfall has occurred, the B type of the water film detection mode of the water film detection system is started; when the determination result is that the rainfall is occurring, the A type of the water film detection mode of the water film detection system is started; in the special water accumulation road section, the road surface water caused by other reasons is detected by the manual starting method, and since the road surface water accumulation in this case is similar to the water accumulation caused by the water film, the B type of the water film detection mode is also used.

3. The method for calculating a water film spatter range of a road surface of a highway according to claim 2, wherein The step 2 detects whether there is a vehicle in the lateral lane of the detected vehicle in real time, and uses a vehicle information acquisition and calculation module to acquire speed information of the detected vehicle in the lateral lane , unit: km / h, position information of the detected vehicle compared with the detecting vehicle , , tire information of the detected vehicle , wherein represents the tire width, unit: cm, tire groove depth, unit: mm, and a position influence determination formula of the detecting vehicle and the detected vehicle; Step 2 includes the following processes: Step 2.1: detecting the existence of the detected vehicle, mainly used to determine whether the detected vehicle exists, and when the detection result is that the detected vehicle exists, acquiring the speed information of the detected vehicle , unit: km / h, and the position information of the detected vehicle , , and the tire information of the detected vehicle ; Step 2.2: In the process of acquiring the speed of the detected vehicle, the speed of the detected vehicle is acquired by the vehicle information acquisition and calculation module, and the speed of the detected vehicle is recorded as , unit: km / h; in the process of recording the position information of the detected vehicle, in order to facilitate calculation and position recording, a rectangular coordinate system is established; the positive direction of the Y axis is the driving direction of the detected vehicle, the positive direction of the X axis is the vertical direction of the driving direction of the detected vehicle, and the intersection of the above X axis and Y axis is the coordinate origin, unit: m; taking the coordinate system as the reference system, the position coordinates of the detected vehicle are recorded, and the position information of the detected vehicle is recorded as , ), wherein represents the position information of the detected vehicle about the X axis of the rectangular coordinate system, represents the position information of the detected vehicle about the Y axis of the rectangular coordinate system; Step 2.3: Obtain the tire information of the detected vehicle Among the influencing factors of vehicle water mist generation, the tire characteristics and area information of the vehicle will affect the water mist generation. The wheel width, wheel pattern and groove depth of the detected vehicle wheel, and the existence of water mist blockers are mainly selected. The above detected information is compiled , wherein represents a set of tire information of the detected vehicle, represents the tire width, unit: cm, tire groove depth, unit: mm, represents the existence of water mist blockers. The water mist blockers are mainly divided into rear water mist blockers and side rear water mist blockers. Step 2.4: Based on the location information of the vehicle being detected obtained in Step 2.1 ( , (and record the speed information of the detected vehicle). Unit: km / h, related to the speed information of the detected vehicle. Unit: km / h; Taking the left and right viewpoints of the detection vehicle as entry points, the position of the vehicle under test appearing within the viewpoint of the detection vehicle is recorded as the positional influence between the detection vehicle and the vehicle under test; the left viewpoint of the vehicle is set to 35 degrees. 。 The right-side view is 60 degrees. 。 In reality, vehicles are constantly moving, so the position information of the detected vehicle and the position information of the vehicle being detected are two curves moving along a certain trajectory; the trajectory curve of the detected vehicle's position information is set as... ; wherein represents a trajectory curve equation of the detected vehicle; represents the detected vehicle's Y-axis coordinate value in the established coordinate system with respect to time t; represents the X-axis coordinate value of the detected vehicle with respect to time t in the established coordinate system; The position information trajectory curve of the vehicle to be detected is set as ; wherein represents a trajectory curve equation of the detected vehicle; represents the Y-axis coordinate value of the detected vehicle with respect to time t in the established coordinate system; represents the X-axis coordinate value of the detected vehicle with respect to time t in the established coordinate system; Detecting the position information of the vehicle , ) and the position information of the detected vehicle , ), determining the field of view range area of the detecting vehicle and setting it as , unit: m 2 ; The position influence determination formula of the detected vehicle and the detected vehicle is established as follows: ； wherein represents a detection vehicle and a detected vehicle's position is influential formula; represents that the position of the detected vehicle has an influence on the detected vehicle being present in the field of view range area of the detecting vehicle ; represents that the position of the detected vehicle has no influence on the detected vehicle being present in the field of view range area of the detecting vehicle .

4. The method for calculating a water film spatter range of a road surface of a highway according to claim 3, wherein In step 3, according to the water film detection mode detected in step 1, the specific water film detection process is carried out, mainly through the water film information collection and detection module to measure the basic information of the water film, and different detection processes are carried out for the A type of the continuous road surface water film detection mode and the B type of the water film detection mode. Step 3 includes the following processes: Step 3.1: A type of continuous road surface water film detection mode, A type of road surface water film, is a layer of water film on the highway due to continuous rainfall, but due to the change of rainfall, the basic information of the road surface water film will be affected, so the road surface water film needs to be detected periodically, and the data obtained by detection is used; In the A-type persistent road surface water film detection process, first, the thickness of the road surface water film is measured, and the thickness of the road surface water film is recorded as mm, in the specific operation process, since the road surface water film is persistent and stays on the surface of the highway, without considering the road slope and the road flatness, the water depth = time difference x light speed / 2 by using the propagation speed of light through different media. The specific formula is as follows: ； wherein represents the thickness of the water film of class A, in mm; represents the time difference between emitting light and receiving light, unit: s; represents the propagation speed of the laser used, in mm / s; Considering that in the actual continuous rainfall, the depth of the road surface water film will change with the change of the rainfall, so the road surface water film needs to be detected in real time, and since the road surface water film needs to be in contact with the vehicle in driving to cause the water mist affecting driving, when the vehicle appears in step 2, the thickness of the road surface water film is measured; Step 3.2: B type of the water film detection mode, B type of the road surface water film, is caused by the unevenness of the road surface after the rainfall, which leads to the generation of the road surface water film, or other reasons cause the phenomenon of the road surface water film; in the B type of the water film detection mode, the position information and the area information of the road surface water film are first measured, and then the thickness information of the water film is measured; In the B type of the water film detection process, a light source emitting device with a light emitting source is first used, when the road surface water is scanned, the image processing display of the light source emitting device will appear different from the image result without water accumulation, and then the length of the water film is detected; When the basic information of the water film is detected, when there is no road surface water, the light HG is directly absorbed by the road surface, when the road surface water appears, the path change of the light is caused due to the reflection phenomenon, the physical change is realized through the physical change; combined with the position information of the real-time water film detector, the physical image of the detected water film information is established, and the principle diagram of the water film detector can be simplified as a physical concept model diagram, in the physical concept diagram The thickness of the water film is represented, and the lengths of other line segments are consistent lengths, so that the application establishes a B-type standing water film thickness information calculation formula: ； wherein the physical concept represented in the figure length, in mm; physical concepts in the figures length, in mm; the sin value of the angle HBZ representing the physical concept in the diagram; The sin value of angle Z, representing the physical concept in the diagram. In practical significance, The thickness of the water film is represented by mm. Considering the non-uniformity of the thickness of the water film on the road surface, the thickness of the water film is measured multiple times. The thickness of the water film is usually not a constant value, and there is a certain water level difference in the same piece of water on the road. Therefore, first, the water film contour diagram of the water film detector is used to establish the center of gravity point of the irregular figure. The center of gravity point is the center point, and the split line of the irregular figure is established. The water film thickness calculation method of the upper diagram is used for the two ends of the split line. Therefore, all the split line segments are marked, and the final water film thickness calculation formula is obtained. 。

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