Continuous dynamic loading system for simulating road ice and snow state evolution under vehicle rolling action

Abstract

The invention discloses a continuous dynamic loading system for simulating road ice and snow state evolution under the rolling action of a vehicle, belongs to the technical field of railway detection equipment, and aims to solve the problem that the prior art cannot meet the requirements of continuity, multiple working conditions and high-efficiency simulation in the research of a coupling mechanism of traffic load and ice and snow state dynamic evolution. The device comprises a frame unit, a rotating and loading unit and N simulation wheel units, N is a positive integer, the inner bottom of the frame unit is used for bearing an ice coating and snow coating simulation experiment asphalt pavement, and the rotating and loading unit is installed at the top of the frame unit. The execution end of the rotating and loading unit extends into the frame unit and is connected with the N simulation wheel units located in the frame unit, and the rotating and loading unit is used for synchronously applying working loads to the N simulation wheel units and synchronously driving the multiple simulation wheel units to move on the experimental road surface in the same direction. The system is mainly used as a loading system in a simulation vehicle road surface rolling experiment.

Description

Technical Field

[0001] This invention belongs to the technical field of road loading experimental equipment, specifically relating to a continuous dynamic loading system that simulates the evolution of road surface ice and snow conditions under vehicle rolling action. Background Technology

[0002] Vehicle compaction is a key physical factor altering the state of icy and snowy roads, accelerating the evolution of the physical properties and macroscopic structure of ice and snow, and directly determining the road surface's skid resistance and driving safety. Therefore, revealing the entire dynamic evolution of road surface icy and snowy conditions under vehicle compaction—from an initial loose snow layer to compacted snow, then to compacted ice, and finally to localized meltwater—is crucial for elucidating the mechanism of winter road surface skid resistance degradation, developing efficient ice suppression and snow removal technologies, and has significant practical implications for improving traffic safety on icy and snowy roads.

[0003] Currently, numerous patents and research studies have proposed various methods for testing the icy and snowy conditions of road surfaces, such as three-dimensional laser texture scanning, infrared multispectral testing, laser ranging snow thickness measurement, and visual image testing. These methods can effectively describe the static characteristics of road surface ice and snow from the perspectives of physical properties and macroscopic structure. However, the actual icy and snowy conditions of road surfaces are subject to continuous interaction between vehicle dynamic loads and the environment, resulting in a complex and continuously changing dynamic process. This evolution process directly determines the degradation behavior of anti-skid performance. While existing static measurement methods can accurately capture the icy and snowy conditions at a specific moment, they are insufficient to effectively reflect the dynamic evolution process of icy and snowy conditions under vehicle loads. The main reason for this is the current lack of a continuous dynamic loading and testing system capable of simulating the vehicle compaction process with high fidelity and working in conjunction with other static measurement equipment. Therefore, to reveal the evolution mechanism of road surface ice and snow conditions under vehicle compaction, it is urgent to develop a novel continuous dynamic loading system. The system needs to be able to simulate the vehicle crushing effect in actual traffic and achieve linkage and integration with the aforementioned static measurement methods, so as to realize in-situ, continuous, and dynamic capture and mechanism analysis of the entire process of ice and snow in real environment from generation, compaction, melting to refreezing.

[0004] Domestic and international research, such as the indoor simulation device for wheel-driven icing and snow accumulation on road surfaces developed by Chang'an University (CN201911276145.3), can simulate the effect of dynamic repeated vehicle loads on the road surface for qualitative evaluation of ice suppression and ice-breaking capabilities. However, this type of device has significant gaps compared to the dynamic response testing requirements of actual road surfaces, mainly in the following aspects: 1) Insufficient continuity. The periodic working cycle and reversing process of reciprocating moving loading cause interruptions in the load application and surface detection process, making it impossible to accurately reproduce the continuous effect of loads in real traffic flow; 2) Single working condition simulation. The system cannot effectively simulate extreme mechanical behaviors such as wheel lock-up during vehicle braking, lacks the ability to reproduce the interaction between ice and snow and the road surface under complex driving conditions, and does not match the mechanical working conditions of actual road surfaces; 3) Low testing efficiency. Each test requires changing the specimen, which is cumbersome and difficult to achieve high-frequency repeated testing, restricting the applicability of research on the evolution law of ice and snow under long-term and multi-cycle loads. The above problems indicate that the existing device is significantly insufficient in simulating the vehicle crushing effect and cannot meet the requirements for continuous, multi-condition, and high-efficiency simulation in the study of the coupling mechanism between traffic load and the dynamic evolution of ice and snow conditions. This further highlights the urgency of developing a new continuous dynamic loading system. Summary of the Invention

[0005] In order to solve the problem that existing technologies cannot meet the requirements of continuous, multi-condition, and high-efficiency simulation in the study of the coupling mechanism between traffic load and the dynamic evolution of ice and snow conditions, this invention provides a continuous dynamic loading system for simulating the evolution of road surface ice and snow conditions under vehicle rolling action.

[0006] A continuous dynamic loading system for simulating the evolution of road surface ice and snow conditions under vehicle rolling action. The continuous dynamic loading system includes a frame unit, a rotation and loading unit, and N simulated wheel units, where N is a positive integer. The inner bottom of the frame unit is used to support the simulated ice and snow-covered experimental asphalt pavement. The rotation and loading unit is installed on the top of the frame unit. The execution end of the rotation and loading unit extends into the frame unit and is connected to the N simulated wheel units located in the frame unit. The rotation and loading unit is used to synchronously apply working loads to the N simulated wheel units and synchronously drive the multiple simulated wheel units to move around the same direction on the experimental road surface.

[0007] Furthermore, the frame unit includes a top support plate, and a ground simulation module is located below the top support plate. The top support plate and the ground simulation module are connected by multiple support structures.

[0008] Furthermore, the support structure is a lifting cylinder or a rigid column;

[0009] Furthermore, the ground simulation module includes a fixed chassis with Z sector-shaped mounting slots machined at equal intervals along the circumference, where Z is a positive integer. Each sector-shaped mounting slot contains a sector-shaped test chamber, which is used to support the simulated icy and snowy asphalt pavement.

[0010] Furthermore, Z sensor modules for observing the road surface condition after tire rolling are installed at the bottom of the top support plate, with each sensor module corresponding to a sector-shaped test chamber.

[0011] Furthermore, the rotation and loading unit includes a drive motor, the housing of which is mounted on the outer top of the top support plate via a motor mounting bracket, the power output shaft of which extends to the bottom of the top support plate and is fixedly connected to the loading module located below the top support plate, and N simulated wheel units are equidistantly arranged on the loading module along the circumference and are detachably connected to the loading disk.

[0012] Furthermore, the loading module includes a vertically arranged loading cylinder. The tail end of the loading cylinder is fixedly connected to the power output shaft of the drive motor. The extension end of the loading cylinder is set towards the ground simulation module, and a loading disk is installed on the extension end of the loading cylinder. N simulated wheel units are equidistantly arranged on the outer circular wall of the loading disk in the circumferential direction and are all detachably connected to the loading disk.

[0013] Furthermore, the simulated wheel unit includes a wheel body, and a connecting shaft is provided between the wheel body and the loading disk. One end of the connecting shaft is fixedly connected to the loading disk, and the other end of the connecting shaft is connected to the wheel body through a universal joint, and the wheel body is rotatably connected to the universal joint.

[0014] Furthermore, the continuous dynamic loading system also includes N braking units, each of which is set above a simulated wheel unit. Each braking unit includes an electric push rod, the tail end of which is fixedly installed at the bottom of the top support plate. A downward braking block is installed on the extended end of the electric push rod, and the downward braking block is located above the wheel body. The electric push rod drives the downward braking block to contact the outer circular surface of the wheel body, thereby constraining the wheel body to rotate around its own axis.

[0015] Furthermore, the value of N ranges from 3 to 5, and the value of Z ranges from 4 to 6.

[0016] The beneficial effects of this application compared to the prior art are:

[0017] 1. This application provides a continuous dynamic loading system for simulating the evolution of road surface ice and snow conditions under vehicle compaction. A ring-shaped loading device is designed to achieve continuous loading and surface testing of icy and snowy road surfaces. A built-in hydraulic control system connected to a load sensor allows for precise control of the applied load according to test requirements. Three independent drive tires are evenly distributed on the lower part of the loading disc, with the tire axles connected to the bottom support of the loading disc via universal joints, ensuring good contact between each tire and the road surface. During testing, the loading disc adjusts the load value according to preset parameters. Driven by servo motors, the three lower tires rotate synchronously around the loading center along a ring track, applying continuous ring-shaped loading to the icy and snowy road surface below, simulating the repeated compaction caused by vehicle movement. The ring-shaped loading device overcomes the technical limitations of traditional reciprocating loading modes. By constructing a continuous cyclic loading path, it eliminates load interruptions caused by periodic reversals, thus more realistically simulating the continuous load process in scenarios such as traffic flow, ensuring the continuity of testing and the consistency of data.

[0018] 2. This application provides a continuous dynamic loading system for simulating the evolution of road surface ice and snow conditions under vehicle compaction. It features a replaceable modular test chamber with an innovative "cake-segmentation" structure, composed of multiple independent, detachable fan-shaped functional modules. Each module can be pre-set with different ice and snow conditions or thicknesses. The upper annular continuous loading component, driven by a servo motor, cyclically loads along a circular track, simultaneously conducting tests on various ice and snow conditions such as loose snow and compacted ice. Combined with real-time data acquisition and analysis by sensors, it significantly improves test efficiency and data comprehensiveness. Through multiple independent, detachable fan-shaped modular test chambers, along with the annular loading device, simultaneous compaction tests on various ice and snow conditions, such as loose snow and compacted ice, can be achieved, significantly improving test efficiency and parallel data acquisition capabilities.

[0019] 3. This application provides a continuous dynamic loading system for simulating the evolution of road surface ice and snow conditions under vehicle rolling action. A braking unit is installed at the corresponding location of each tire. When tire locking is required, an electric push rod drives a downward-pressing brake block to contact the outer circumference of the wheel body. The friction and normal pressure generated between the downward-pressing brake block and the wheel body achieve rigid locking between the tire and the axle. This design effectively simulates typical pure lock-up braking conditions. The unit has a simple and compact structure, reliable operation, and provides accurate experimental conditions for braking performance research. Its mechanical self-locking characteristics also ensure the stability of the simulation. Attached Figure Description

[0020] Figure 1 This is an overall schematic diagram of the continuous dynamic loading system described in this application;

[0021] Figure 2This is a schematic diagram of the continuous dynamic loading system described in this application.

[0022] Figure 3 for Figure 2 A magnified view of a section at point A in the middle;

[0023] Figure 4 for Figure 2 A magnified view of a section at point B in the middle;

[0024] Figure 5 This is a point cloud image formed after rolling over a road test specimen with an ice thickness of 0.5 mm.

[0025] Figure 6 This application presents the evolution curve of icy road surface state under simulated vehicle rolling action;

[0026] Figure 7 This application presents the SMTD evolution curve of an icy road surface under simulated vehicle rolling action.

[0027] In the diagram: 1 Drive motor, 2 Road condition sensor, 3 Braking unit, 4 Universal joint, 5 Fixed chassis, 6 Sector-shaped test chamber, 7 Wheel body, 8 Loading cylinder, 9 Top support plate, and 10 Laser texture sensor. Detailed Implementation

[0028] Specific implementation method one: Combining Figures 1 to 7 This embodiment describes a continuous dynamic loading system for simulating the evolution of road surface ice and snow conditions under vehicle rolling. The continuous dynamic loading system includes a frame unit, a rotation and loading unit, and N simulated wheel units, where N is a positive integer. The inner bottom of the frame unit is used to support the simulated ice and snow-covered experimental asphalt pavement. The rotation and loading unit is installed on the top of the frame unit. The execution end of the rotation and loading unit extends into the frame unit and is connected to the N simulated wheel units located within the frame unit. The rotation and loading unit is used to simultaneously apply working loads to the N simulated wheel units and simultaneously drive the multiple simulated wheel units to move around the same direction on the experimental road surface.

[0029] The frame unit includes a top support plate 9, and a ground simulation module is located below the top support plate 9. The top support plate 9 and the ground simulation module are connected by multiple support structures.

[0030] The ground simulation module includes a fixed chassis 5, on which Z sector-shaped mounting slots are machined at equal intervals along the circumference, where Z is a positive integer. Each sector-shaped mounting slot contains a sector-shaped test chamber 6, which is used to support the simulated ice and snow accretion asphalt pavement.

[0031] Z sensor modules for observing the road surface condition after tire rolling are installed at the bottom of the top support plate 9. Each sensor module is set up with a sector-shaped test chamber 6.

[0032] The rotation and loading unit includes a drive motor 1. The housing of the drive motor 1 is mounted on the top of the top support plate 9 via a motor mounting bracket. The power output shaft of the drive motor 1 extends to the bottom of the top support plate 9 and is fixedly connected to the loading module located below the top support plate 9. N simulated wheel units are equidistantly arranged on the loading module along the circumference and are detachably connected to the loading disk.

[0033] The simulated wheel unit includes a wheel body 7. A connecting shaft is provided between the wheel body 7 and the loading disk. One end of the connecting shaft is fixedly connected to the loading disk, and the other end of the connecting shaft is connected to the wheel body 7 through a universal joint 4. The wheel body 7 and the universal joint 4 are rotatably connected.

[0034] The continuous dynamic loading system also includes N braking units 3, each braking unit 3 is set above a simulated wheel unit. The braking unit 3 includes an electric push rod, the tail end of which is fixedly installed at the bottom of the top support plate 9. A downward braking block is installed on the extended end of the electric push rod. The downward braking block is located above the wheel body 7. The electric push rod drives the downward braking block to contact the outer circular surface of the wheel body 7, thereby constraining the wheel body 7 to rotate around its own axis.

[0035] This embodiment presents a continuous dynamic loading system for simulating the evolution of road surface ice and snow conditions under vehicle compaction. Addressing the dynamic testing requirements of actual icy and snowy roads, this system integrates continuous compaction, multi-condition coordination, and combined simulation. The system employs a ring-shaped loading device (comprising a rotating and loading unit and N simulated wheel units), achieving seamless continuous loading and testing of icy and snowy roads, effectively overcoming the inefficiencies and load interruptions inherent in traditional reciprocating loading methods. The braking unit 3 accurately simulates two typical mechanical conditions: free rolling of vehicle tires and brake lock-up. Furthermore, the system design utilizes multiple independent, detachable, fan-shaped modular test chambers to support coordinated and combined testing of multiple conditions under different icy and snowy environments. This system can complete in-situ testing of road surface ice and snow conditions during continuous dynamic loading, providing a reliable experimental method for revealing the dynamic evolution mechanism of ice and snow conditions under vehicle loads.

[0036] In this embodiment, the sensor module includes a road surface condition sensor 2 and a laser texture sensor 10. The road surface condition sensor 2 is installed on the side near the tire contact area and uses the multispectral principle to detect the macroscopic condition of the road surface (such as dryness, icing, and snow accumulation) and the thickness of the overlay in real time. The laser texture sensor 10 uses laser triangulation to scan and acquire two-dimensional or three-dimensional micro-texture data of the road surface before and after compaction with high precision.

[0037] In this embodiment, a controller and a storage device are also installed on the top of the top support plate 9. The controller is a PLC controller. The PLC controller is connected to the control terminal of the drive motor 1, the control terminal of the electric push rod, the control terminal of the road condition sensor 2 and the laser texture sensor 10 through wires. The PLC controller is used to control the working status of the drive motor 1, the electric push rod, the road condition sensor 2 and the laser texture sensor 10. The data collected by the road condition sensor 2 and the laser texture sensor 10 will be transmitted to the storage device through wires for subsequent analysis.

[0038] The ground simulation module mainly consists of two parts: a fixed chassis 5 and a sector-shaped test chamber 6. The fixed chassis 5 has a spaced-apart crossbeam structure on its upper part, forming an interlocking area between the crossbeams. The sector-shaped test chamber 6 has two corresponding fan-corner connecting parts at its bottom, which can be embedded into the interlocking area of ​​the fixed seat for rapid positioning and reliable fixation. This connection structure provides stable mechanical constraints to the test chamber during the wheel-rolling test, ensuring a safe and reliable testing process.

[0039] Braking unit 3 is used for emergency braking of the tires rotating around itself. Since the wheel body 7 and the universal joint 4 are connected by bearings, when the rotation and loading unit drives multiple simulated wheel units to rotate circumferentially, the wheel body 7 in each simulated wheel unit will rotate around its own axis under the action of friction between it and the simulated road surface to simulate the state of the wheel in daily forward movement. When it is necessary to brake the wheel, simulating the wheel in a locked state and the simulated road surface crushing state, the electric push rod will drive the downward brake block to move downward and contact the wheel body 7. Under the longitudinal extrusion pressure, the wheel body 7 will no longer rotate around its own axis, changing its original rotational friction into sliding friction. This unit has a compact structure and reliable locking, and can accurately simulate the typical working condition of the tires being completely locked when the vehicle is braking.

[0040] Specific Implementation Method Two: Combining Figures 1 to 7 This embodiment differs from Specific Embodiment 1 in that the support structure is a lifting cylinder or a rigid column. Other components and connection methods are the same as in Specific Embodiment 1.

[0041] In this embodiment, a rigid column is used as the support structure, which helps to simplify the structure of the continuous dynamic loading system. By using a rigid column as the support component, the support stability between the top support plate 9 and the fixed chassis 5 can be guaranteed, while the construction cost of the system can also be reduced. Using a lifting cylinder as the support structure can not only guarantee the support stability between the top support plate 9 and the fixed chassis 5, but also adjust the working distance between them. This allows it to be used for simulation work of more sizes of simulated wheel units, thus improving the versatility of the system.

[0042] Specific implementation method three: Combining Figures 1 to 7 This embodiment differs from Specific Embodiment Two in that the loading module includes a vertically arranged loading cylinder 8. The tail end of the loading cylinder 8 is fixedly connected to the power output shaft of the drive motor 1. The extension end of the loading cylinder 8 faces the ground simulation module, and a loading disk is installed on the extension end of the loading cylinder 8. N simulated wheel units are equidistantly arranged circumferentially on the outer circular wall of the loading disk and are all detachably connected to the loading disk. Other components and connection methods are the same as in Specific Embodiment Two.

[0043] In this embodiment, the loading cylinder 8 is mainly used to apply longitudinal load to multiple simulated wheel units. Before the drive motor 1 starts rotating, the loading cylinder 8 is driven to a designated extension position through an external air circuit, that is, a predetermined load is applied to the loading plate. After the loading cylinder 8 is extended and stabilized, the air inlet and outlet of the loading cylinder 8 are sealed by a flow limiting valve, and the external air circuit is removed so that the loading cylinder 8 always remains in the extended state. At this time, the drive motor 1 is controlled to rotate to achieve the purpose of ring loading. In order to further explore the state parameters of the tire after rolling on the icy and snowy road surface, a laser snow depth sensor and a high-speed camera can also be integrated and installed at the bottom of the loading plate to collect data such as the state of ice and snow on the simulated road surface after rolling and the snow depth after rolling.

[0044] Specific implementation method four: Combination Figures 1 to 7 This embodiment describes a test method for assessing the evolution of road surface ice and snow under vehicle compaction, implemented using the aforementioned continuous dynamic loading system that simulates the evolution of road surface ice and snow under vehicle compaction. The test method for assessing the evolution of road surface ice and snow under vehicle compaction is carried out according to the following steps:

[0045] Step 1: Experimental Preparation and Initial State Scan

[0046] The prepared fan-shaped asphalt concrete specimens were installed in the fan-shaped test chamber 6 and reliably fixed by the fixed base 5. The assembled specimens were then moved into a constant temperature chamber for more than 6 hours to ensure that the specimen temperature was completely consistent with the ambient temperature. For icing scenario simulation, a fixed amount of water was sprayed evenly onto the specimen surface in a mist using a pneumatic sprayer. For road snow accumulation requirements, a fixed amount of snow was weighed through a standard sieve with a 0.6 mm aperture and evenly spread onto the specimen surface. The thickness of the snow cover was monitored in real time using a laser snow depth sensor until the sensor feedback value reached the preset target snow thickness. Then, the thickness of the ice and snow layer was monitored in real time using a remote sensing road condition sensor until the sensor feedback value reached the preset target thickness.

[0047] The mass of water required for complete icing of an asphalt pavement is calculated using the inverse mass method, and the formula is as follows:

[0048]

[0049] Where: m w —The required mass of water, in grams; ρ i —Ice density, taken as 0.9 g / cm³ 3 S—Road surface area, calculated based on the actual area of ​​the asphalt road surface requiring ice and snow simulation, in cm². 2 h i —Ice thickness, in mm;

[0050] For the snow cover requirements on the road surface, a certain amount of snow is weighed through a standard sieve with a 0.6mm aperture and evenly spread on the surface of the specimen. The thickness of the snow cover is monitored in real time using a laser snow depth sensor until the sensor feedback value reaches the preset target snow thickness.

[0051]

[0052] Where: m s —The required mass of snow, in grams; ρ s —Snow density, taken as 0.3 g / cm³ 3 S—Road surface area, calculated based on the actual area of ​​the asphalt road surface requiring ice and snow simulation, in cm². 2 h s —Snow cover thickness, in mm;

[0053] After the system starts, the control loading cylinder 8 lifts the tire body 7 to a safe height and confirms that the braking unit 3 has been released. The controller initializes the road condition sensor and the laser texture sensor. Before the formal compaction, the laser texture sensor 10 is used to perform a high-resolution scan of the initial micro-texture of the road surface to build a baseline three-dimensional model. At the same time, the road condition sensor 2 is used to collect the initial macro-state parameters of the ice and snow layer. All initial data are completely recorded and stored as the baseline values ​​for state evolution.

[0054] Step 2: Synchronize parameter settings and system startup;

[0055] Based on real road test data and numerical simulation results, a basic conversion model for vehicle axle load, tire pressure, and ground contact pressure is established using an equivalent conversion method. The calculation formulas are as follows:

[0056]

[0057] Where: p0—ground pressure, in MPa; p1—tire pressure, in MPa; p—vehicle axle load, in kg; g—gravity coefficient, in N / kg;

[0058] The axle loads of the five representative vehicle models involved in this application are detailed in Table 1:

[0059] Vehicle type Grounding pressure (MPa) <![CDATA[Tire pressure p1 (MPa)]]> Vehicle axle load (kg) Passenger car 0.51 0.62 1500 large bus 0.52 0.62 2000 medium-sized trucks 0.68 0.65 7000 large trucks 0.76 0.68 9000 Heavy trucks 0.86 0.70 12000

[0060] Table 1. Grounding pressure characteristics of representative vehicles

[0061] The test parameters are set by the control unit of the continuous dynamic loading system. In a preferred embodiment, the parameters include: the vertical pressure applied by the loading cylinder 8 to the tire body 7 is set to 14700N (vertical pressure is the weight corresponding to the vehicle axle load, g is taken as 9.8N / kg, and the calculated ground pressure is 0.5051MPa, rounded to two decimal places, rounded to 0.51MPa); the rotational speed of the drive motor 1 is set to 20r / min; and the total number of rolling cycles performed by the system is set to 1000.

[0062] To accurately simulate the braking behavior of a real vehicle in an emergency, a specific point of operation that triggers tire lock-up is preset in the control unit. Specifically, the command to activate the braking unit 3 is set to be issued at the 600th rolling cycle. When the system reaches this preset number of cycles, the electric push rod drives the lowered brake block to contact the tire body 7, thereby preventing the tire body 7 from rotating around its own axis and realistically simulating the tire lock-up braking condition.

[0063] As a key aspect of this implementation, precise configuration of the data acquisition system is required. The acquisition modes of the road condition sensor 2 and the laser texture sensor 10 are set to be triggered by the same synchronization signal from the controller, ensuring that all acquired data have a consistent, high-precision timestamp. Preferably, the data acquisition interval is set to 3 seconds per acquisition. This setting ensures that the acquired macroscopic state data and microscopic texture data can achieve strict synchronization and deep fusion in time series throughout the entire compaction process, laying the foundation for subsequent analysis of the precise correlation between tire behavior and the evolution of road surface ice and snow conditions.

[0064] After all parameters are set and confirmed to be correct, the system will enter automatic operation mode according to the preset instructions;

[0065] Step 3: Synchronous Data Acquisition under Dynamic Compaction and Braking Condition Simulation

[0066] After the system starts, the drive motor 1 begins to operate, and its output torque is transmitted to the actuator tire body 7 through the connecting shaft and universal joint 4. The drive tire body 7 performs continuous and stable circular rolling motion on the surface of the ice and snow test specimen laid in the fan-shaped test chamber 6. Figure 1 When the number of rolling cycles reaches 800, the braking unit 3 is activated to simulate the braking condition.

[0067] Throughout the dynamic compaction process (covering both normal rolling and braking lock-up stages), the sensing unit continuously performs high-frequency synchronous acquisition of multimodal data: the road condition sensor 2, installed on the side of the tire contact area, monitors and records in real time the dynamic changes in the macroscopic state of the road surface adjacent to the tire contact area, including data on the compaction, melting, and thinning of the ice and snow layer; the laser texture sensor 10, in high-frequency trigger mode, continuously scans the microscopic texture of the road surface along the same scanning path during the gaps in tire compaction, capturing instantaneous changes in microscopic features such as ice and snow particle distribution and surface roughness.

[0068] Step 4: Data Processing

[0069] The initial state, collected before formal compaction, serves as the absolute baseline. This includes the initial ice and snow thickness recorded by road surface condition sensor 2, and a high-precision baseline 3D model established by laser texture sensor 10 (see...). Figure 5 All subsequent changes are calculated relative to this baseline.

[0070] For the continuous data stream collected in real time by road condition sensor 2, the average ice and snow thickness corresponding to each compaction cycle is directly extracted. This data directly reflects the dynamic changes in the macroscopic morphology of the ice and snow layer under tire load, such as compaction and melting. For different initial ice and snow thicknesses, the evolution of the ice and snow road surface state under vehicle compaction is shown in [see figure]. Figure 6 As shown.

[0071] For the 3D point cloud data acquired by the laser texture sensor, the average texture depth of the icy and snowy road surface in each cycle is calculated to characterize the surface complexity. The calculation formula is as follows:

[0072]

[0073] In the formula: z(xi, yi) — elevation corresponding to a point on the surface to be measured, in mm; M, N — number of discrete sampling points in the x and y directions on the surface to be measured; z p (xi, yi)——Elevation of the highest point within the surface to be measured, in mm.

[0074] For different initial icing thicknesses, the evolution of SMTD (Surface Mobility and Damping) of icy pavement under vehicle compaction is shown in the figure. Figure 7 As shown.

[0075] The present invention has been disclosed above with preferred embodiments, but it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed structure and technical content to create equivalent embodiments without departing from the scope of the present invention. However, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

[0076] Working principle

[0077] The continuous dynamic loading system provided in this application, which simulates the evolution of road surface ice and snow conditions under vehicle rolling action, first applies a set vertical load to multiple simulated wheel units by controlling the loading cylinder 8 after entering the working state. Subsequently, the drive motor 1 starts running, and the power is transmitted to the loading plate through the loading cylinder 8, causing the loading plate to rotate. As the loading plate rotates, the tire body 7, which is connected to the loading plate circumferentially through the connecting shaft and universal joint 4, also rotates synchronously to achieve circular rolling on the simulated road surface. At the same time, the road condition sensor 2 and the laser texture sensor 10 collect data on the rolled road surface, acquiring road surface data in real time during the rolling process. All signals are synchronously recorded by the data acquisition card for subsequent analysis. When it is necessary to simulate braking conditions, the tire can be instantly locked by operating the braking unit 3. At this time, the rotational friction between the tire body 7 and the simulated road surface changes to sliding friction. The road condition sensor 2 and the laser texture sensor 10 continue to collect data on the simulated road surface to obtain the state data of the road surface after the tire slides into contact with the ground under braking conditions.

Claims

1. A continuous dynamic loading system for simulating the evolution of the state of ice and snow on a road surface under the action of a vehicle, characterized in that it comprises: The continuous dynamic loading system comprises a frame unit, a rotating and loading unit and N simulated wheel units, N being a positive integer, the inner bottom of the frame unit is used for bearing simulated icing and snow-covered experimental asphalt pavement, the rotating and loading unit is installed on the top of the frame unit, the execution end of the rotating and loading unit extends into the frame unit and is connected with the N simulated wheel units located in the frame unit, the rotating and loading unit is used for synchronously applying working load to the N simulated wheel units and synchronously driving the multiple simulated wheel units to move on the experimental pavement in the same direction.

2. The continuous dynamic loading system for simulating the evolution of the state of the road surface under the action of a vehicle according to claim 1, characterized in that: The frame unit comprises a top support plate (9), a ground simulation module is arranged below the top support plate (9), and the top support plate (9) and the ground simulation module are connected through multiple support structures.

3. The continuous dynamic loading system for simulating the evolution of the state of the road surface under the action of a vehicle according to claim 1, characterized in that: The support structure is a lifting cylinder or a rigid column.

4. The continuous dynamic loading system for simulating the evolution of the state of the pavement covered with ice and snow under the action of a vehicle according to claim 3, characterized in that: The ground simulation module comprises a fixed base plate (5), Z sector-shaped installation grooves are equidistantly processed on the fixed base plate (5) in the circumferential direction, Z being a positive integer, one sector-shaped test bin (6) is arranged in each sector-shaped installation groove, and the sector-shaped test bin (6) is used for bearing simulated icing and snow-covered experimental asphalt pavement.

5. The continuous dynamic loading system for simulating the evolution of the state of the pavement covered with ice and snow under the action of a vehicle according to claim 4, characterized in that: Z sensor modules for observing the pavement state after tire rolling are arranged on the bottom of the top support plate (9), and each sensor module is arranged in correspondence with one sector-shaped test bin (6).

6. The continuous dynamic loading system for simulating the evolution of the state of the pavement covered with ice and snow under the action of a vehicle according to claim 5, characterized in that: The rotating and loading unit comprises a driving motor (1), the shell of the driving motor (1) is installed on the outer top of the top support plate (9) through a motor mounting frame, the power output shaft of the driving motor (1) extends below the top support plate (9) and is fixedly connected with a loading module located below the top support plate (9), and the N simulated wheel units are equidistantly arranged on the loading module in the circumferential direction and are detachably connected with the loading disc.

7. The continuous dynamic loading system for simulating the evolution of the state of the pavement covered with ice and snow under the action of a vehicle according to claim 6, characterized in that: The loading module comprises a vertically arranged loading cylinder (8), the tail fixed end of the loading cylinder (8) is fixedly connected with the power output shaft of the driving motor (1), the extension end of the loading cylinder (8) is arranged towards the ground simulation module, and the extension end of the loading cylinder (8) is provided with the loading disc, and the N simulated wheel units are equidistantly arranged on the outer circular wall of the loading disc in the circumferential direction and are detachably connected with the loading disc.

8. The continuous dynamic loading system for simulating the evolution of the state of a road surface covered with ice and snow under the action of a vehicle according to claim 7, characterized in that: The simulated wheel unit comprises a wheel body (7), a connecting shaft is arranged between the wheel body (7) and the loading disc, one end of the connecting shaft is fixedly connected with the loading disc, the other end of the connecting shaft is connected with the wheel body (7) through a universal joint (4), and the wheel body (7) is rotationally connected with the universal joint (4).

9. The continuous dynamic loading system for simulating the evolution of the state of a road surface covered with ice and snow under the action of a vehicle according to claim 8, characterized in that: The continuous dynamic loading system further comprises N brake units (3), each brake unit (3) is arranged above one simulated wheel unit, the brake unit (3) comprises an electric push rod, the tail end of the electric push rod is fixedly installed on the bottom of the top support plate (9), a downward pressing brake block is arranged on the extension end of the electric push rod, the downward pressing brake block is located above the wheel body (7), the electric push rod drives the downward pressing brake block to contact the outer circular surface of the wheel body (7) and thus restricts the wheel body (7) from rotating around the axis thereof.

10. The continuous dynamic loading system for simulating the evolution of the state of a road surface covered with ice and snow under the action of a vehicle according to claim 1, characterized in that: The value range of N is 3-5, and the value range of Z is 4-6.

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