Driving load identification method and system based on rainy day ground spiral ramp

Abstract

The invention relates to the technical field of intelligent traffic safety, and discloses a driving load identification method based on a rainy day ground spiral ramp, and the method comprises the following steps: 1, dividing the spiral ramp according to circle layers, and collecting the road data, 24-hour rainfall and vehicle types of the ground of each circle layer; the road data comprises a longitudinal slope ia, a transverse slope angle beta and a ramp radius R; 2, the water film thickness D is calculated according to the 24-hour rainfall, and the transverse friction factor f'of the road section is calculated through the water film thickness D; 3, the sideslip speed V is calculated according to the road data and the transverse friction coefficient f '; 4, the heart rate growth rate N of the driver is calculated according to the sideslip speed V; and 5, judging the driving load condition of the driver according to the heart rate growth rate N of the driver, and carrying out early warning on the driver so as to adjust the driving behavior. In practical application, the scheme effectively improves the driving load of the driver on the ground spiral ramp in rainy days for accurate identification, and the driving safety is improved.

Description

Technical Field

[0001] The present invention relates to the field of intelligent traffic safety technology, and in particular to a driving load identification method based on a rainy ground spiral ramp and a system thereof. Background Art

[0002] With the continuous development of urban transportation networks, the construction of underground roads and viaducts has become one of the key measures to solve urban traffic bottlenecks. Among these transportation facilities, ground spiral ramps, as a common road design form, are widely used in urban transportation systems because they can effectively solve height difference problems and improve traffic mobility.

[0003] However, although spiral ramps have the advantages of improving traffic flow and saving space, their special curve shape and slope design also make it easy for drivers to bear a large driving load when passing through. The driving load usually includes the driver's reaction time, control strength, concentration, and physical stress during driving. In severe weather conditions, the driving load problem is more prominent; especially in complex climatic environments such as rainy days, factors such as slippery roads and limited visibility significantly affect the driving stability and safety of vehicles, and drivers must concentrate more to cope with complex traffic conditions; the above factors work together to increase the psychological and physiological burden on drivers, thereby increasing driving load and increasing driving risks. In complex weather conditions, the driver's load level increases significantly. Therefore, accurate identification of driving load on ground spiral ramps on rainy days has become the key to improving traffic safety and driving experience. Summary of the invention

[0004] The present invention aims to provide a driving load identification method based on a ground spiral ramp on rainy days, so as to achieve accurate identification of the driving load of the driver on the ground spiral ramp on rainy days and improve driving safety.

[0005] To achieve the above object, the present invention adopts the following technical solution: a driving load identification method based on a spiral ramp on a rainy day, comprising the following steps:

[0006] Step 1: Divide the spiral ramp into layers and collect the road data, 24-hour rainfall and vehicle type of each layer; the road data includes the longitudinal slope i a , transverse slope angle β, ramp radius R;

[0007] Step 2: Calculate the water film thickness D according to the 24-hour rainfall, and calculate the lateral friction factor f' of the road section through the water film thickness D;

[0008] Step 3: Calculate the side slip speed V according to the road data and the lateral friction coefficient f';

[0009] Step 4, calculating the driver's heart rate growth rate N according to the sideslip speed V;

[0010] Step 5: judging the driver's driving load according to the driver's heart rate growth rate N, and giving the driver a warning, thereby adjusting the driver's driving behavior;

[0011] The calculation formula for the heart rate growth rate in step 4 is:

[0012] N = [-81e (-0.025V) +62]×100%

[0013] In the above formula, N is the driver's heart rate growth rate, and V is the sideslip speed.

[0014] With the continuous increase in the number of vehicles and the increasing complexity of road conditions, achieving safe driving has become a top priority. Quantifying the driving load of the driver during the driving journey is a key step to achieve safe driving, and the key to quantifying the driving load is accurate identification. At present, there are methods for driving load identification, but most existing identification technologies still have certain limitations. Traditional driving load identification methods often rely too much on a single factor, such as vehicle acceleration, speed or steering angle, etc. These methods cannot fully consider the multi-dimensional characteristics of driving load. Weather conditions, as an important "variable" for safe driving, add great complexity to driving load identification. On rainy days, raindrops hit the car window and affect the line of sight, and the slippery road surface reduces the adhesion of the tires. The driver needs to pay more attention to maintain the stable driving of the vehicle, and the driving load is significantly increased at this time. When encountering complex road environments such as spiral ramps, the continuous changes in curves, the ups and downs of the slope, and the limited field of view, multiple unfavorable factors overlap, making it difficult for traditional driving load identification methods to accurately and real-time capture the dynamic changes of driving load.

[0015] Therefore, this scheme provides an identification method that combines basic road data and rainy day environmental factors to quantify the driver's driving load. The principles and advantages of this scheme are:

[0016] 1. This solution divides the spiral ramp into circles and collects road data on the ground of each circle in detail, including longitudinal slope, transverse slope angle, ramp radius, and 24-hour rainfall and vehicle model information. Unlike traditional driving load identification methods that rely too much on a single factor, this multi-dimensional data collection mode breaks the limitations and comprehensively covers the key factors that affect driving load. Combined with rainfall data, it accurately grasps the key variables under complex weather conditions such as rainy days, fully considers the changes in the friction characteristics of the road surface caused by the thickness of the water film, and lays a solid foundation for the subsequent accurate calculation of driving load. By combining these factors, the real driving scene on the spiral ramp on the ground on rainy days can be fully reflected, avoiding deviations in driving load assessment due to missing information.

[0017] 2. The water film thickness is calculated through 24-hour rainfall, and the lateral friction factor of the road section is further obtained. This process greatly improves the accuracy of the assessment of rainy road conditions. On rainy days, slippery road surface is one of the core factors that lead to a sudden increase in driving risks. Traditional methods are difficult to effectively measure its specific impact on driving load. This solution uses a scientific calculation model to establish a correlation between rainfall, water film thickness and friction factor, and can accurately quantify the changes in friction between vehicle tires and the road surface. When the lateral friction factor decreases, the vehicle is more likely to skid when driving on a curve, and the driver must exert greater control force to maintain the driving direction, which undoubtedly significantly increases the driving load. By accurately mastering this key parameter, not only can the stability risk of vehicle driving be predicted in advance, but it can also provide a key basis for subsequent driver load calculations, making the entire driving load identification system more in line with actual rainy driving conditions.

[0018] 3. This solution calculates the sideslip speed based on road data and the accurately derived lateral friction coefficient, and conducts real-time dynamic monitoring of driving risks based on the principles of vehicle dynamics. The sideslip speed directly reflects the potential tendency of the vehicle to deviate from the stable driving trajectory under the current road conditions and driving conditions. In complex terrain such as spiral ramps, the curves change continuously and the slope fluctuates. When the vehicle slides, the driver needs to react in a very short time. The high intensity of mental concentration and rapid control response cause the driving load to increase sharply. By calculating the sideslip speed in real time, the system can keenly capture dangerous moments during driving and provide timely feedback to the driver, so that he can know the potential risks in advance, adjust the driving strategy, and effectively reduce the probability of accidents.

[0019] 4. This solution establishes a connection between the side slip speed and the driver's heart rate growth rate, and uses this to judge the driver's driving load. The heart rate growth rate is an intuitive indicator of the driver's physiological stress response, which can truly reflect the degree of psychological and physiological burden during driving. When the vehicle is driving on a spiral ramp on a rainy day and faces various complex road conditions, the driver's heart rate will increase as the driving difficulty increases. By accurately monitoring the heart rate growth rate, the system can accurately identify the driver's current load state. Once the heart rate growth rate exceeds the preset threshold, the driver will be immediately warned to adjust his driving behavior, such as slowing down appropriately, increasing the following distance, etc., which fundamentally ensures driving safety and improves the driving experience.

[0020] Furthermore, the degree of driving load is divided into the following specific ways:

[0021] When the driver's N range is ≤25%, the driver's driving load is defined as low load;

[0022] When the driver's N range is 26%-40%, the driver's driving load is defined as medium load;

[0023] When the driver's N range is ≥40%, the driver's driving load is defined as high load;

[0024] When the driver's driving load is medium or high, a load warning is issued.

[0025] Beneficial effects: The above settings divide the driver's heart rate growth rate into a clear range, and clearly define the driving load into three levels: low, medium and high, making the evaluation results of driving load more intuitive and accurate; through the specific numerical range, the driver's load state can be accurately known, which not only provides a clear self-cognition for the driver himself, but also provides a standardized data reference for traffic management departments and relevant researchers, which is helpful to further carry out traffic behavior analysis, accident prevention research and other work.

[0026] Further, in step 3, the calculation formula of the sideslip speed V is:

[0027]

[0028] In the formula, E i is the adjustment factor for different driving styles of drivers, T i are the characteristic parameters of different models, f' is the lateral friction factor, g is the gravitational acceleration, i a is the longitudinal slope, β is the transverse slope angle, and R is the ramp radius.

[0029] Beneficial effects: The calculation formula of the sideslip speed comprehensively considers factors such as driving style, vehicle type characteristics, water film thickness, lateral friction factor, longitudinal slope, ramp radius, etc., reflecting the influence of various relevant parameters on the sideslip speed, and performs real-time calculation and analysis according to actual conditions to obtain more accurate sideslip speed calculation results, which provides a solid data basis for the subsequent judgment, warning and driving behavior intervention of the driver's driving load, and effectively reduces the safety risks caused by the sideslip speed when the driver is driving on the spiral ramp.

[0030] Furthermore, in step 2, the calculation formula for the water film thickness D under different rainfall intensities is:

[0031] D=0.15(LI) 1 / 2 N 1 / 2

[0032] Where L is the drainage length, I is the rainfall intensity, and 1 / N is the slope;

[0033] In step 2, the calculation formula of the lateral friction factor f' and the water film thickness D is:

[0034] f′=-0.0010D 2 -0.0025D+0.7144

[0035] Beneficial effects: 1. The calculation formula for water film thickness incorporates multiple key factors such as drainage length, rainfall intensity and slope. By combining these factors, the water film thickness of the road surface under different rainfall conditions can be calculated more accurately; therefore, it can adapt to various rainfall scenarios, whether it is short-term heavy rainfall or long-term light rain, the water film thickness can be accurately calculated based on the actual drainage length, rainfall intensity and slope data, providing more realistic data support for subsequent driving load assessment.

[0036] 2. The calculation formula for the lateral friction factor and the water film thickness clarifies the functional relationship between the two. This correlation makes the evaluation of road friction characteristics more scientific and accurate. On rainy days, changes in the thickness of the water film will directly affect the friction between the tire and the road, and thus affect the driving stability of the vehicle and the difficulty of the driver's control. Through this formula, the lateral friction factor can be accurately obtained based on the calculated water film thickness, which provides a key intermediate parameter for the subsequent calculation of the sideslip speed and the evaluation of the driving load. For example, when the water film thickness increases, the lateral friction factor will decrease accordingly, the vehicle will be more likely to side slip, the driver will need greater control force to maintain vehicle stability, and the driving load will increase accordingly. This formula can accurately reflect this change process.

[0037] Furthermore, the vehicle types in step 1 are divided into the following categories according to length and weight:

[0038] Large vehicle: The length exceeds 7 meters and the load capacity exceeds 6 tons. Its characteristic parameter is set to 0.4, that is, T1 = 0.4;

[0039] Small car: length not exceeding 7 meters, load capacity not exceeding 6 tons, its characteristic parameter is set to 0.6, that is, T2=0.6.

[0040] Beneficial effects: Classifying vehicles into large and small vehicles according to weight and length can more accurately reflect the driving characteristics of vehicles on multi-layer spiral ramps. Generally, large vehicles are more sensitive to ramp slope, radius and adhesion coefficient due to their heavy weight, while small vehicles are relatively less sensitive. By classifying multi-layer spiral ramp models, the safety of the ramp can be improved and the accident rate can be reduced.

[0041] Furthermore, the driving styles of drivers are specifically divided as follows:

[0042] For drivers with an aggressive driving style, the adjustment factor is set to 1.4, that is, E1 = 1.4;

[0043] For drivers with normal driving style, the adjustment factor is set to 1.0, that is, E2 = 1.0;

[0044] For drivers with a conservative driving style, the adjustment factor is set to 0.8, that is, E3=0.8.

[0045] Beneficial effects: In the study of driving behavior, driving style is an important factor affecting driving safety and traffic operation efficiency. This program divides driving styles into conservative, normal and aggressive types. Different driving styles have their own significant characteristics and have different effects on driving behavior and traffic safety. Conservative drivers usually drive at low speeds, brake less frequently, maintain a larger distance between vehicles, and are more stable when operating on spiral ramps; normal drivers usually drive at moderate speeds, operate smoothly, and are more stable during the operation of curves; aggressive drivers usually drive at faster speeds, are more impatient during the operation, and are eager when operating on curves.

[0046] The present invention also provides a driving load identification system based on a rainy ground spiral ramp for implementing the above identification method, comprising a data acquisition module, a data transmission module, an intelligent calculation algorithm module and an information feedback loop module;

[0047] The data acquisition module is used to collect road data, 24-hour rainfall, and vehicle model;

[0048] The data transmission module is used to transmit the data collected by the data acquisition module to the intelligent calculation algorithm module;

[0049] The intelligent calculation algorithm module is used to calculate the driver's heart rate growth rate under different rainfall intensities based on the collected data, and estimate the driver's heart rate growth rate. If the current driver's heart rate growth rate is medium load or high load, the warning information is transmitted to the information feedback loop module;

[0050] The information feedback loop module includes a dynamic intelligent guidance device and an adaptive driving vision; the dynamic intelligent guidance device is used to dynamically publish driving load information and provide safe driving guidance; the adaptive driving vision is used to receive warning information and remind the driver to adjust the driving load.

[0051] Beneficial effects of this program:

[0052] In this solution, the data acquisition component and the data transmission component collect data in real time and transmit it to the intelligent calculation algorithm module, so that the calculated driving load is dynamic real-time data, and abnormal conditions of the driver are discovered in time, and then dynamic reminders and warnings are given through information feedback loop modules such as dynamic intelligent guidance devices and adaptive driving vision; among them, the dynamic intelligent guidance device can dynamically publish the flashing light system of the driving load and set up the signboard of the entrance section on the roadside; the adaptive driving vision can receive warning information and remind the driver to adjust the driving load. By integrating road data, rainfall, speed and other data, using intelligent algorithms to dynamically evaluate the driver's heart rate growth rate under different rainfall intensities, real-time detection of driving load conditions, and providing accurate warnings and guidance through information feedback loop modules, driving safety is improved, the burden on drivers is reduced, and the risk of accidents is reduced.

[0053] Furthermore, the dynamic intelligent guidance device includes a roadside warning device and a dynamic warning device. The roadside warning device is set 100m before the entrance of the spiral ramp, and the dynamic warning device is set from the entrance section to the exit section of the spiral ramp.

[0054] The roadside warning device includes a roadside rainy weather sign and a display screen. The display screen is an LED screen. The radar sensor measures the propagation time of the wave to determine the position of the vehicle. When the vehicle enters the gantry 100m before the ground spiral ramp, the screen will display the words "Slippery road ahead, slow down"; the roadside rainy weather sign is installed on the roadside 100m before the ground spiral ramp to remind drivers to pay attention to safety;

[0055] The dynamic warning device includes a flashing light system, which arranges flashing lights in a ring at intervals of 30m and lights up in sequence according to the different circles of the spiral ramp; as the vehicle travels along the spiral ramp, the flashing lights in each circle will light up in sequence to provide a continuous warning signal, and the flashing frequency is as follows:

[0056] When the driver's driving load reaches medium load, the flashing light flashes yellow at a frequency of 20 times / min;

[0057] When the driver's driving load reaches a high level, the flashing light flashes red at a frequency of 40 times / min.

[0058] Beneficial effects:

[0059] 1. An LED roadside warning device is installed before the entrance of the spiral ramp. In rainy days, it will issue a dynamic reminder to the driver 100m in advance, "The road ahead is slippery, slow down and drive slowly", which effectively improves the driver's risk prediction ability, prompting him to slow down in advance, reduce the risk of accidents caused by slippery roads, and further improve the safety of driving on the ramp.

[0060] 2. Install dynamic warning devices on spiral ramps in rainy days. By arranging flashing lights in a circle every 30 meters on the spiral ramp and lighting them up in sequence according to the ramp circles, the warning efficiency and road safety are effectively improved. It can provide visual reminders to drivers, especially in low visibility and slippery road conditions, to enhance driver attention and driving safety, and reduce the risk of accidents caused by slippery roads. In addition, dynamic reminders are given at different frequencies and colors according to the different driving load levels, realizing real-time and intuitive risk warnings. The reason why yellow and red flashing lights are chosen is their high warning and visibility. These two colors have longer wavelengths and strong penetration, and are clearly visible in low visibility environments such as heavy rain. At the same time, red conveys emergency and danger information, which can quickly alert drivers, while yellow is used to remind attention and potential risks. In addition, the selection of red and yellow flashing lights is in line with the driver's cognitive habits and traffic design specifications, which helps drivers quickly view warning information and take timely countermeasures.

[0061] Furthermore, the adaptive driving view includes two interfaces, namely, the adaptive driving view and the real-time road condition reflector; the adaptive driving view includes a load degree display block and a load level display block. The load degree display block is a circular indicator device, which is used to display the driver's two-level driving load degree, namely, medium load and high load. When a new load is reached, the load degree display block will flash a yellow light for 2-3 seconds; the load level display block is a fan-shaped indicator device, which is used to indicate the specific proportion of each load level, namely, 20%, 40%, 60% and 80%; when the medium load driving degree exceeds 80%, the load degree display block will display high load;

[0062] The real-time traffic reflector collects information based on road conditions and transmits it to the adaptive driving view in real time to dynamically reflect current road conditions.

[0063] Beneficial effects: The above settings present the changes in the driver's driving load degree and level ratio in real time and intuitively through the load degree display block and load level display block of the adaptive driving vision, and attract the driver's attention through flashing prompts. When the driving load reaches a critical state, the system can switch to display a higher level of load status in time, helping the driver to quickly understand the current pressure level and take corresponding adjustment measures, thereby improving driving safety and comfort, while reducing the possibility of risks caused by excessive driving load. On the other hand, through the combination of real-time road condition reflectors and adaptive display screens, dynamic monitoring and intuitive display of road conditions and driving loads are achieved. The driver can grasp the current road conditions and his own driving load status in real time, so as to adjust the driving speed and driving behavior in time, reduce the risk of accidents caused by excessive driving load, and greatly improve driving safety, stability and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 Schematic diagram of the identification system of embodiment 2 of the present invention.

[0065] Figure 2 This is a schematic diagram of the structure of a double-layer spiral ramp according to Example 1 of the present invention.

[0066] Figure 3 Schematic diagram of an LED display screen according to Embodiment 2 of the present invention.

[0067] Figure 4 This is a schematic diagram of a roadside rainy day sign according to Embodiment 2 of the present invention.

[0068] Figure 5 This is a schematic diagram of the interior layout of a vehicle according to Embodiment 2 of the present invention.

[0069] Figure 6 This is a schematic diagram of a smart display screen according to Embodiment 2 of the present invention.

[0070] Figure 7 This is a schematic diagram of the structure of the flashing lights on the spiral ramp of Example 2 of the present invention. DETAILED DESCRIPTION

[0071] The following is further described in detail through specific implementation methods:

[0072] The figure marks in the drawings of the specification include: roadside rainy day sign 1, vehicle distance confirmation line 2, LED display screen 3, flashing light system 4, smart display screen 5, real-time road condition reflector 6, adaptive driving vision 7, instrument panel 8, digital media player 9, high-precision radar navigation 10, flashing light 11, reflective sign 12.

[0073] Example 1

[0074] A driving load identification method based on spiral ramp on rainy days is applied to Figure 2 The double-layer spiral ramp shown in the figure, the double-layer spiral ramp, starting from the entrance, takes the first circle at the bottom of the ramp radius of 50m as the first layer of the double-layer spiral ramp, and takes the second circle at the top of the ramp radius of 60m as the second layer of the double-layer spiral ramp; specifically includes the following steps:

[0075] Step 1: Divide the spiral ramp into layers and collect the road data, 24-hour rainfall and vehicle type of each layer; the road data includes the longitudinal slope i a , transverse slope angle β, ramp radius R;

[0076] Step 2: Calculate the water film thickness D according to the 24-hour rainfall, and calculate the lateral friction factor f' of the road section through the water film thickness D. The specific calculation formula is:

[0077] f′=-0.0010D2 -0.0025D+0.7144

[0078] Step 3: Calculate the sideslip speed V according to the road data and the lateral friction coefficient f'. The specific calculation formula is:

[0079]

[0080] Step 4: Calculate the driver's heart rate growth rate N according to the sideslip speed V. The specific calculation formula is:

[0081] N = [-81e (-0.025V) +62]×100%

[0082] Furthermore, the calculation formula of the heart rate growth rate N is:

[0083]

[0084] In the above formula, N is the driver's heart rate growth rate, V is the sideslip speed, g is the gravity acceleration, D is the water film thickness, i a is the longitudinal slope, R is the ramp radius, β is the transverse slope angle, E i is the adjustment factor for different driving styles of drivers, T i Characteristic parameters of different models.

[0085] Step 5: Determine the driver's driving load according to the driver's heart rate growth rate N, and issue a warning to the driver, so as to adjust the driving behavior. Specifically, the degree of driving load is divided as follows:

[0086] When the driver's N range is ≤25%, the driver's driving load is defined as low load;

[0087] When the driver's N range is 26%-40%, the driver's driving load is defined as medium load;

[0088] When the driver's N range is ≥40%, the driver's driving load is defined as high load;

[0089] When the driver's driving load is medium or high, a load warning is issued.

[0090] The calculation formula for the water film thickness D under different rainfall intensities in step 4 is:

[0091] D=0.15(LI) 1 / 2 N 1 / 2

[0092] Where L is the drainage length, usually 3.75m, I is the rainfall intensity, 1 / N = i a For the slope.

[0093] Furthermore, the degree of slipperiness is divided according to the thickness of the water film under different rainfall intensities. The specific divisions are as follows

[0094] When the 24-hour rainfall is ≤10mm, the water film thickness is 3-5mm; the degree of slipperiness is slightly slippery;

[0095] When the rainfall in 24 hours is 10mm-24.9mm, the water film thickness is 5-7mm; the degree of slipperiness is relatively slippery;

[0096] When the 24-hour rainfall is 25mm-44.9mm, the water film thickness is 7-9mm; the degree of slipperiness is very slippery.

[0097] The calculation formula for water film thickness incorporates several key factors such as drainage length, rainfall intensity and slope. By combining these factors, the water film thickness of the road surface under different rainfall conditions can be calculated more accurately. Therefore, it can adapt to various rainfall scenarios, whether it is short-term heavy rainfall or long-term light rain, the water film thickness can be accurately calculated based on the actual drainage length, rainfall intensity and slope data, providing more realistic data support for subsequent driving load assessment. Moreover, the calculation formula for the lateral friction coefficient and water film thickness clarifies the functional relationship between the two, making the assessment of road friction characteristics more scientific and accurate.

[0098] Among them, the vehicle types in step 1 are classified according to length and weight, and different parameter weights are assigned, which are specifically divided as follows: large vehicle: length exceeds 7 meters, load capacity exceeds 6 tons, and its characteristic parameter is set to 0.4, that is, T1=0.4; small vehicle: length does not exceed 7 meters, load capacity does not exceed 6 tons, and its characteristic parameter is set to 0.6, that is, T2=0.6.

[0099] Furthermore, by introducing the spectral clustering algorithm, driving styles are divided into three types according to driving behavior characteristics: conservative, normal and aggressive. Different driving styles have their own significant characteristics and have different effects on driving behavior and traffic safety.

[0100] Conservative drivers usually drive at low speeds, brake less frequently, keep a larger distance between vehicles, and are more stable when driving on spiral ramps; normal drivers usually drive at a moderate speed, operate smoothly, and are more stable when driving on curves; aggressive drivers usually drive at a faster speed, operate more impatiently, and are more eager when driving on curves. The specific classification is as follows:

[0101] For drivers with an aggressive driving style, the adjustment factor is set to 1.4, that is, E1 = 1.4;

[0102] For drivers with normal driving style, the adjustment factor is set to 1.0, that is, E2 = 1.0;

[0103] For drivers with a conservative driving style, the adjustment factor is set to 0.8, that is, E3=0.8.

[0104] In actual design, due to structural strength, driving comfort and safety, the parameters of each layer of the spiral ramp, such as radius, slope, friction coefficient, etc., are different. In view of this, the road parameters of each layer of the double-layer spiral ramp are collected for example verification. The road data collected from the first layer of the spiral ramp in this embodiment are as follows: longitudinal slope i a =5%, superelevation tanβ=3.0%, ramp radius R=50m, gravitational acceleration g=10km / h.

[0105] (1) Assume that a driver with an aggressive driving style drives a small car on a slippery road on the first spiral ramp with a 24-hour rainfall of 18 mm. The water film thickness parameter corresponding to the slipperiness is 6 mm; the driving style adjustment factor E1 = 1.4; the small car characteristic parameter T2 = 0.6;

[0106] The calculation formula for the lateral friction factor and water film thickness of the spiral ramp is f′=0.6634

[0107] The calculation formula for the water film thickness and sideslip speed in the first spiral ramp is: V = 56.87 km / h

[0108] Similarly, if the radius of the second ramp is R = 60m, the calculation formula for the water film thickness and sideslip speed in the second spiral ramp is: V = 62.31km / h

[0109] The driver's heart rate when driving on the first circle spiral ramp is N=42%; the driver's heart rate when driving on the second circle spiral ramp is N=44%; according to the degree of driving load, the driver's driving load is high when driving on the first and second circle spiral ramps, and a load warning is issued. The driver needs to make timely adjustments to ensure safe driving.

[0110] (2) Assume that a driver with an aggressive driving style drives a large vehicle on a slippery road surface of the first spiral ramp with a 24-hour rainfall of 30 mm. The water film thickness parameter corresponding to the slipperiness is 8 mm; the driving style adjustment factor E1 = 1.4; and the large vehicle T1 = 0.4;

[0111] The calculation formula for the lateral friction factor and water film thickness of the spiral ramp is f′=0.6304

[0112] The calculation formula for the water film thickness and sideslip speed in the first spiral ramp is: V = 36.99 km / h

[0113] Similarly, if the radius of the second ramp is R = 60m, the calculation formula for the water film thickness and sideslip speed in the second spiral ramp is: B = 40.52km / h

[0114] The driver's heart rate when driving on the first circle spiral ramp is N=29%; the driver's heart rate when driving on the second circle spiral ramp is N=32%; according to the degree of driving load, the driver's driving load when driving on the first and second circle spiral ramps is medium load, and load warning is issued. The driver needs to make timely adjustments to ensure safe driving.

[0115] Example 2

[0116] A driving load identification system based on a rainy ground spiral ramp for implementing the identification method of embodiment 1, such as Figure 1 As shown, it includes: a data acquisition module, a data transmission module, an intelligent calculation algorithm module and an information feedback loop module;

[0117] The data acquisition module is used to collect road data, 24-hour rainfall, and vehicle model;

[0118] The data transmission module is used to transmit the data collected by the data acquisition module to the intelligent calculation algorithm module;

[0119] The intelligent calculation algorithm module is used to calculate the driver's heart rate growth rate under different rainfall intensities based on the collected data, and estimate the driver's heart rate growth rate. If the current driver's heart rate growth rate is medium load or high load, the warning information is transmitted to the information feedback loop module;

[0120] The information feedback loop module includes a dynamic intelligent guidance device and an adaptive driving horizon 7; wherein the dynamic intelligent guidance device is used to dynamically publish driving load information and provide safe driving guidance; the adaptive driving horizon 7 is used to receive warning information and remind the driver to adjust the driving load.

[0121] The dynamic intelligent guidance device includes a roadside warning device and a dynamic warning device. The roadside warning device is set 100m before the entrance of the spiral ramp, and the dynamic warning device is set from the entrance section to the exit section of the spiral ramp.

[0122] Combination Figure 2 , Figure 3As shown, the roadside warning device includes a roadside rainy day sign 1 and a display screen, wherein the display screen is an LED display screen 3, which is installed on a 100m gantry before the entrance of the first circle spiral ramp. The radar sensor measures the propagation time of the wave to determine the position of the vehicle. A vehicle distance confirmation line 2 is provided at the entrance of the gantry to guide safe driving. When the vehicle enters the gantry 100m before the entrance of the ground spiral ramp, the LED display screen 3 will display the words "Slippery road ahead, slow down". The LED display screen 3 uses dynamic warnings on rainy days and static warnings in other weather conditions. Figure 4 As shown, the roadside rainy day sign 1 is installed on the roadside 100m before the ground spiral ramp enters the curve section. The roadside rainy day sign 1 is installed at 10° to the center line of the road and its height is 2m to remind drivers to pay attention to safety.

[0123] Combination Figure 2 , Figure 7 As shown, the dynamic warning device includes a flashing light system 4, in which flashing lights 11 are arranged in a ring at intervals of 30 m, and are lit up in sequence according to different circles of the spiral ramp, and reflective signs 12 are provided between adjacent flashing lights 11; as the vehicle travels along the spiral ramp, the flashing lights 11 of each circle will light up in sequence to provide a continuous warning signal, and the flashing frequency is as follows:

[0124] When the driver's driving load reaches medium load, the flashing light 11 flashes yellow at a frequency of 20 times / min;

[0125] When the driver's driving load reaches a high load, the flashing light 11 flashes red at a frequency of 40 times / min.

[0126] The dynamic warning device is installed in a loop with a 30m interval to ensure that the driver can capture the position of the next flashing light 11 under the action of the previous flashing light 11, forming a continuous visual guidance; rainy days and spiral ramps may affect the driver's field of vision, and the 30m loop layout interval can effectively cover the visual blind spot, ensuring that the driver can be within the warning range of the flashing light 11 when the load is too high on rainy days.

[0127] Combination Figure 5 and Figure 6As shown, the adaptive driving view 7 is arranged on the intelligent display screen 5 of the vehicle, and the left and right sides are respectively a dashboard 8, a high-precision radar navigation 10 and a digital media player 9. The adaptive driving view 7 includes two interfaces, namely the adaptive driving view 7 and a real-time road condition reflector 6; the adaptive driving view 7 includes a load degree display block and a load level display block. The load degree display block is a circular indicator device for displaying the driver's two levels of driving load, namely medium load and high load. When a new load is reached, the load degree display block will flash a yellow light for 2-3 seconds; the load level display block is a sector-shaped The indicator device is used to indicate the specific proportion of each load level, which is 20%, 40%, 60% and 80% respectively; when the medium load driving degree exceeds 80%, the load degree display block will show high load; the real-time road condition reflector 6 is installed on the vehicle to collect information according to the road condition and transmit it to the adaptive driving vision 7 in real time to dynamically reflect the current road condition, and the adaptive driving vision 7 in the vehicle is used to display the driver's current driving load degree and the duration of the current driving load degree, so as to remind the driver to adjust the vehicle speed, adjustment amplitude and direction and reduce the driver's driving load.

[0128] Based on the situation (1) of Example 1, the driver's heart rate is N=42% when driving in the first circle, and N=44% when driving in the second circle, both of which are high load; when the driver drives the first circle, the flashing light 11 on the bottom layer flashes red light at a frequency of 40 times / min, and the flashing light 11 on the top layer is in the off state; if the driver drives to the second circle, the driver is still in a high load state, at this time, the flashing light system 4 of the two layers will flash red light at a frequency of 40 times / min at the same time; if the driver drives to the second circle, due to the effect of the flashing light system 4, the driver's driving load is reduced to medium load, and the flashing light system 4 of the two layers will flash yellow light at a frequency of 20 times / min at the same time. Secondly, when the driver is driving on a double-layer spiral ramp, the circular indicator device on the left side of the adaptive driving horizon 7 will display the words "high load". When entering "high load", the circular indicator device will flash red light for 2-3s to remind the driver to reduce the driving load. The sector indicator device on the right will present a sector ratio according to the driver's heart rate. When the driver's heart rate continues to be in a high-load state, the first grid and the second grid will flash in sequence until the full grid reaches the high-load state. The driver will be reminded by voice to reduce the driving load.

[0129] Based on the (2) situation of Example 1, the driver's heart rate is N=29% when driving in the first circle, and N=32% when driving in the second circle, both of which are medium load; when the driver drives in the first circle, the bottom flashing light 11 flashes yellow light at a frequency of 20 times / min, and the top flashing light 11 is in the off state; when the driver is driving, the heart rate will gradually increase with the change of vehicle speed, and may reach a high load situation. At this time, the flashing light 11 flashes red light at a frequency of 40 times / min. If the driver is still in a medium load situation when driving in the second circle, at this time, the two-layer flashing light system 4 will flash yellow light at a frequency of 20 times / min at the same time; if the driver is in a high load situation when driving in the second circle, at this time, the bottom flashing light system 4 will flash yellow light at a frequency of 20 times / min; the top flashing light system 4 will flash red light at a frequency of 40 times / min. Secondly, when the driver is driving on a double-layer spiral ramp, the driving load is medium load. At this time, the circular indicator on the left side of the adaptive driving vision 7 will display the words "medium load". When entering "medium load", the circular indicator will flash a yellow light for 2-3 seconds to remind the driver to reduce the driving load. The sector indicator on the right will display a sector ratio according to the driver's heart rate. When the driver's heart rate continues to be in the medium load state, the first grid will appear and the second grid will flash in sequence until entering the next level of load state.

[0130] The above is only an embodiment of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A driving load identification method based on a spiral ramp on a rainy day, characterized by: The following steps are involved: Step 1: Divide the spiral ramp into layers and collect the road data, 24-hour rainfall and vehicle type of each layer; the road data includes the longitudinal slope i a , transverse slope angle β, ramp radius R; Step 2: Calculate the water film thickness D according to the 24-hour rainfall, and calculate the lateral friction factor f' of the road section through the water film thickness D; Step 3: Calculate the side slip speed V according to the road data and the lateral friction coefficient f'; Step 4, calculating the driver's heart rate growth rate N according to the sideslip speed V; Step 5: judging the driver's driving load according to the driver's heart rate growth rate N, and giving the driver a warning, thereby adjusting the driver's driving behavior; The calculation formula for the heart rate growth rate in step 4 is: N=[-81e (-0.025V) +62]×100% In the above formula, N is the driver's heart rate growth rate, and V is the sideslip speed.

2. The method for identifying driving load based on a spiral ramp on a rainy day according to claim 1, characterized in that: The degree of driving load is divided into the following specific ways: When the driver's N range is ≤25%, the driver's driving load is defined as low load; When the driver's N range is 26%-40%, the driver's driving load is defined as medium load; When the driver's N range is ≥40%, the driver's driving load is defined as high load; When the driver's driving load is medium or high, a load warning is issued.

3. The driving load identification method based on a spiral ramp on a rainy day according to claim 1 is characterized by: In step 3, the calculation formula of the sideslip speed V is: In the formula, E i is the adjustment factor for different driving styles of drivers, T i are the characteristic parameters of different models, f' is the lateral friction factor, g is the gravitational acceleration, i a is the longitudinal slope, β is the transverse slope angle, and R is the ramp radius.

4. The method for identifying driving load based on a spiral ramp on a rainy day according to claim 1, characterized in that: In step 2, the calculation formula for the water film thickness D under different rainfall intensities is: D=0.15(LI) 1 / 2 N 1 / 2 Where L is the drainage length, I is the rainfall intensity, and 1 / N is the slope; In step 2, the calculation formula of the lateral friction factor f' and the water film thickness D is: f′=-0.0010D 2 -0.0025D+0.7144。 5. The method for identifying driving load based on a spiral ramp on a rainy day according to claim 1, characterized in that: The vehicle types in step 1 are divided into the following categories according to length and weight: Large vehicle: The length exceeds 7 meters and the load capacity exceeds 6 tons. Its characteristic parameter is set to 0.4, that is, T1 = 0.4; Small car: length not exceeding 7 meters, load capacity not exceeding 6 tons, its characteristic parameter is set to 0.6, that is, T2=0.

6.

6. The method for identifying driving load based on a spiral ramp on a rainy day according to claim 1, characterized in that: The driving styles of drivers are classified as follows: For drivers with an aggressive driving style, the adjustment factor is set to 1.4, that is, E1 = 1.4; For drivers with normal driving style, the adjustment factor is set to 1.0, that is, E2 = 1.0; For drivers with a conservative driving style, the adjustment factor is set to 0.8, that is, E3=0.

8.

7. A driving load identification system based on a rainy ground spiral ramp for implementing any of the identification methods of claims 1-6, characterized in that: It includes data acquisition module, data transmission module, intelligent calculation algorithm module and information feedback loop module; The data acquisition module is used to collect road data, 24-hour rainfall, and vehicle model; The data transmission module is used to transmit the data collected by the data acquisition module to the intelligent calculation algorithm module; The intelligent calculation algorithm module is used to calculate the driver's heart rate growth rate under different rainfall intensities based on the collected data, and estimate the driver's heart rate growth rate. If the current driver's heart rate growth rate is medium load or high load, the warning information is transmitted to the information feedback loop module; The information feedback loop module includes a dynamic intelligent guidance device and an adaptive driving vision; wherein the dynamic intelligent guidance device is used to dynamically publish driving load information and provide safe driving guidance; Adaptive driving vision is used to receive warning information and remind the driver to adjust the driving load.

8. The driving load identification system based on a rainy ground spiral ramp according to claim 7 is characterized by: The dynamic intelligent guidance device includes a roadside warning device and a dynamic warning device. The roadside warning device is set 100m before the entrance of the spiral ramp, and the dynamic warning device is set from the entrance to the exit of the spiral ramp. The roadside warning device includes a roadside rainy weather sign and a display screen. The display screen is an LED screen. The radar sensor measures the propagation time of the wave to determine the position of the vehicle. When the vehicle enters the gantry 100m before the ground spiral ramp, the screen will display the words "slippery road ahead, slow down"; the roadside rainy weather sign is installed on the roadside 100m before the ground spiral ramp to remind drivers to pay attention to safety; The dynamic warning device includes a flashing light system, which arranges flashing lights in a ring at intervals of 30m and lights up in sequence according to the different circles of the spiral ramp; as the vehicle travels along the spiral ramp, the flashing lights in each circle will light up in sequence to provide a continuous warning signal, and the flashing frequency is as follows: When the driver's driving load reaches medium load, the flashing light flashes yellow at a frequency of 20 times / min; When the driver's driving load reaches a high level, the flashing light flashes red at a frequency of 40 times / min.

9. The driving load identification system based on a spiral ramp on a rainy day according to claim 8, characterized in that: Adaptive driving vision includes two interfaces, namely adaptive driving vision and real-time road condition reflector; The adaptive driving vision includes a load degree display block and a load level display block. The load degree display block is a circular indicator device, which is used to display the driver's two levels of driving load, namely medium load and high load. When a new load is reached, the load degree display block will flash a yellow light for 2-3 seconds; the load level display block is a fan-shaped indicator device, which is used to indicate the specific proportion of each load level, which are 20%, 40%, 60% and 80% respectively; when the medium load driving degree exceeds 80%, the load degree display block will display high load; The real-time traffic reflector collects information based on road conditions and transmits it to the adaptive driving view in real time to dynamically reflect current road conditions.

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