Road surface friction coefficient testing device, system and testing method

Abstract

The present application relates to a kind of road surface friction coefficient testing device, system and testing method, wherein testing device includes friction sheet, test matrix being arranged above friction sheet, counterforce maintaining mechanism being located above test matrix and fixed ground reflector plate;Counterforce maintaining mechanism is provided with fixed ground support leg at both ends, and the upper portion of test matrix is provided with pressure regulating mechanism;Friction sheet and test matrix are configured to be relatively slid along counterforce maintaining mechanism;The upper portion of friction sheet is provided with pressure sensor;The side of test matrix is provided with tension sensor, and the other side of test matrix is provided with laser displacement sensor;Test matrix is provided with timer;Reflector plate is set to reflect the light signal emitted by laser displacement sensor.The present application solves the problem that the repeatability and comparability of data of swing instrument, lateral force coefficient and dynamic friction coefficient and other test methods are relatively poor.

Description

TECHNICAL FIELD

[0001] The present application relates to the road technical field, especially to a road surface friction coefficient testing device, system and testing method. BACKGROUND

[0002] The road surface skid resistance is a surface feature of the road, which refers to the resistance or inhibition ability of the road surface to the slip phenomenon occurring in the process of vehicle driving. This performance is crucial for driving safety, especially when driving a vehicle under wet or snowy conditions. Insufficient road surface skid resistance often leads to brake failure, causing serious loss of life and property and serious adverse consequences. Therefore, the testing of road surface skid resistance is crucial for the grasp of road safety conditions.

[0003] The road surface skid resistance is mainly affected by road surface materials, road surface texture, road surface structure and environmental conditions. At present, the road surface skid resistance is mainly evaluated by the road surface texture depth and the road surface friction coefficient.

[0004] The existing road surface friction coefficient detection methods and their advantages and disadvantages are mainly as follows:

[0005] I. Pendulum method. The pendulum method is to release the pendulum of the pendulum instrument from a certain height, impact the road surface, and then measure the backswing height of the pendulum to calculate the friction coefficient of the road surface. Advantages: 1. Easy to operate, and the instrument is easy to carry; 2. Can be tested at different temperatures, and the friction coefficient at standard temperature can be obtained through temperature correction. Disadvantages: 1. Human factors have a greater impact, such as the release height and angle of the pendulum, which will affect the test results if not standardized; 2. The test efficiency is low, only one point can be tested at a time, and a large number of test points are needed to reflect the overall situation of the road surface.

[0006] II. Transverse force coefficient testing method. The transverse force coefficient testing method is to determine the friction coefficient of the road surface by testing the ratio of the transverse force to the vertical force received by the wheel during vehicle driving. The test wheel is at a certain angle with the road surface, and when the vehicle is driving, the test wheel receives the lateral friction force of the road surface, which is measured by a sensor and the friction coefficient is calculated. Advantages: 1. Fast testing speed, can be tested at normal driving speed; 2. Can quickly obtain a large amount of road surface friction coefficient data; 3. Less affected by environmental temperature. Disadvantages: 1. The instrument is relatively complex and expensive; 2. The test results are greatly affected by factors such as tire wear and air pressure; 3. The flatness of the test road is required to be high, and uneven road surface will affect the accuracy of the test results.

[0007] Three, dynamic friction coefficient tester method. Dynamic friction coefficient tester method is through simulating the dynamic contact process of vehicle tire and road surface, measuring the dynamic friction force between tire and road surface, and then calculating the dynamic friction coefficient of road surface. Advantages: 1, the test result can reflect the road surface friction performance under the actual driving condition more; 2, the friction coefficient under different speeds is tested, which has important significance for studying the road surface safety performance when driving at high speed. Disadvantages: 1, the instrument equipment is complex, and the operation difficulty is big; 2, the test result is influenced by many factors, such as tire characteristics, loading mode, road surface temperature and humidity; 3, the repeatability and comparability of data are relatively poor.

[0008] From the above, the existing road surface friction coefficient detection methods all have deficiencies. SUMMARY

[0009] In view of the deficiencies of the prior art, the application discloses a road surface friction coefficient testing device, system and testing method.

[0010] The technical scheme adopted by the application is as follows:

[0011] In a first aspect, a road surface friction coefficient testing device is provided, comprising a friction sheet, a test base arranged above the friction sheet, a counterforce maintaining mechanism arranged above the test base, and a reflecting plate fixed to the ground; both ends of the counterforce maintaining mechanism are provided with legs fixed to the ground, and the upper part of the test base is provided with a pressure adjusting mechanism; the friction sheet and the test base are configured to slide relative to the counterforce maintaining mechanism; a pressure sensor is arranged above the friction sheet; a tension sensor is arranged on one side of the test base, and a laser displacement sensor is arranged on the other side of the test base; the test base is provided with a timer; and the reflecting plate is arranged to reflect the light signal emitted by the laser displacement sensor.

[0012] In an embodiment of the application, the counterforce maintaining mechanism extends in the horizontal direction, and the extension length is greater than the sum of the movement distance of the test base and the length of the test base during testing; the counterforce maintaining mechanism comprises a pressing plate in rolling connection with the test base; and the pressing plate is provided with a counterweight.

[0013] In an embodiment of the application, the pressure adjusting mechanism comprises a hydraulic cylinder arranged in the vertical direction and a pressure head connected with the acting end of the hydraulic cylinder; and the pressure head faces the counterforce maintaining mechanism.

[0014] In an embodiment of the application, a traction mechanism is further included; the traction mechanism is arranged to pull the friction sheet and the test base to move in the horizontal direction; the traction mechanism comprises a winch connected with the test base and a water tank arranged on the winch; and the water tank is provided with a water inlet and a water outlet.

[0015] In one embodiment of the present application, the traction mechanism further comprises a sprayer arranged in front of the water outlet.

[0016] In one embodiment of the present application, a plurality of calibration blocks with different roughness levels are further included; the calibration blocks are arranged to correct the test error of the road surface friction coefficient testing device.

[0017] In a second aspect, a road surface friction coefficient testing system is provided, comprising:

[0018] a control module;

[0019] a road surface friction coefficient testing device as described above, and the control module is connected.

[0020] In a third aspect, a road surface friction coefficient testing method is provided, which utilizes the road surface friction coefficient testing system as described above, and comprises the following steps:

[0021] S1, the control module controls the pressure adjusting mechanism to cooperate with the counterforce maintaining device to apply and maintain pressure on the test base body, and the pressure sensor records the pressure;

[0022] S2, the control module controls the traction mechanism to apply tension to the test base body and the friction sheet, and to pull the test base body and the friction sheet to move at a constant speed in the horizontal direction; the tension sensor records the tension, the laser displacement sensor records the movement distance of the test base body, and the timer records the test time;

[0023] S3, the static friction coefficient and the dynamic friction coefficient are calculated according to the tension and the pressure, and a dynamic change curve of the dynamic friction coefficient with time, a dynamic change curve of the dynamic friction coefficient with distance, and a dynamic change curve of the dynamic friction coefficient with tension are generated.

[0024] In one embodiment of the present application, further comprising:

[0025] Before step S1, step S0 is performed:

[0026] A calibration block with a theoretical friction coefficient close to that of the test area is selected, and the maximum tension required for the test base body and the friction sheet to start moving relative to each other under test conditions, the tension required for the test base body and the friction sheet to move at a constant speed relative to each other on the calibration block, and the pressure on the pressure sensor are measured, so as to obtain the friction coefficient of the calibration block under test conditions; according to the friction coefficient under test conditions and the theoretical friction coefficient, a correction amount is obtained and input into the control module.

[0027] and

[0028] Step S4: According to the correction amount and the static friction coefficient and the dynamic friction coefficient obtained in step S3, the corrected static friction coefficient and the dynamic friction coefficient are obtained, and the dynamic change curve of the corrected dynamic friction coefficient with time, the dynamic change curve of the corrected dynamic friction coefficient with distance and the dynamic change curve of the corrected dynamic friction coefficient with tension are generated.

[0029] In one embodiment of the application, steps S5 and S6 are further included: step S5: according to any one of the methods of the Liuda criterion, the quartile distance method and the standard score method, the abnormal values of the corrected dynamic friction coefficient are eliminated to obtain the effective dynamic friction coefficient and the average value of the effective dynamic friction coefficient; and step S6: the values evaluating the stability and uniformity of the effective dynamic friction coefficient are calculated and output according to the effective dynamic friction coefficient.

[0030] The above technical solutions of the application have the following advantages compared with the prior art:

[0031] The road surface friction coefficient testing device solves various problems caused by the swing type instrument method, the swing type instrument method, the lateral force coefficient testing method and the dynamic friction coefficient testing method. The repeatability and comparability of the data obtained by testing using the road surface friction coefficient testing device are relatively good.

[0032] The road surface friction coefficient testing system can obtain the static friction coefficient and the dynamic friction coefficient in one test.

[0033] The road surface friction coefficient testing method analyzes and statistically processes the test results, eliminates abnormal values and calculates the average value, the dispersion and other indexes. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to make the content of the application more easily understood, the application will be further described in detail below according to specific embodiments of the application and in combination with the drawings.

[0035] Figure 1 is a schematic view of the road surface friction coefficient testing device in the application.

[0036] Figure 2 is Figure 1 is a schematic view of the road surface friction coefficient testing device in the application.

[0037] Figure 3 is a schematic view of the road surface friction coefficient testing system in the application.

[0038] Figure 4 is a flowchart of the road surface friction coefficient testing method in the application.

[0039] DESCRIPTION OF DRAWINGS

[0040] 100, control module; 200, test base; 201, pressure sensor; 202, tension sensor; 203, timer; 204, laser displacement sensor; 205, reflecting plate; 300, traction mechanism; 301, winch; 302, water tank; 3021, water inlet; 3022, water outlet; 303, sprayer; 400, counterforce maintaining mechanism; 401, pressure plate; 402, rolling element; 403, leg; 404, fastening element; 500, friction plate; 600, energy storage mechanism; 700, pressure adjusting mechanism. DETAILED DESCRIPTION

[0041] The present application will be further described by examples with reference to the drawings attached hereto. The examples are presented herein for the purpose of illustration only and should not be construed to limit the scope of the present application.

[0042] The foregoing and other features and advantages of the present application will be further described and become apparent in the following detailed description of the embodiments, taken in conjunction with the accompanying drawings. Directional terms as used herein— for example, up, down, right, left, front, rear, etc.— are made only relative to the points of reference as set forth herein, and therefore, are not to be construed as limiting the present application unless specifically so defined. In addition, like reference numerals are intended to represent like elements throughout the various examples and figures.

[0043] In conjunction with Figure 1 and Figure 2 A road surface friction coefficient testing device includes a friction plate 500, a test base 200 disposed above the friction plate 500, a counterforce maintaining mechanism 400 disposed above the test base 200, and a reflecting plate 205 fixed to the ground. The counterforce maintaining mechanism 400 has legs 403 fixed to the ground at both ends, and the test base 200 has a pressure adjusting mechanism 700 disposed at the upper portion. The friction plate 500 and the test base 200 are configured to slide relative to each other along the counterforce maintaining mechanism 400. The friction plate 500 has a pressure sensor 201 disposed above. The test base 200 has a tension sensor 202 disposed at one side and a laser displacement sensor 204 disposed at the other side. The test base 200 has a timer 203 disposed thereon. The reflecting plate 205 is configured to reflect the light signal emitted by the laser displacement sensor 204.

[0044] Among them, the rubber sheet is generally selected as the friction plate 500, and the reasons are as follows: elastic deformation adapts to the unevenness of the road surface and the wide range of working temperature. In addition, the rubber sheet is the only specified material in international / domestic standards such as ASTM E303, EN 13036-4, JTG E60-2008, which ensures that the test results can be directly compared with the historical database, and avoids the standard deviation caused by material differences. It should be noted that in addition to the commonly used rubber sheet as the friction plate 500, the following materials can also be selected to meet the needs of different test environments, temperature ranges and friction performance:

[0045] I. Semi-metallic friction material, composed of metal fiber + rubber + friction powder, high hardness, wear resistance, high friction coefficient, suitable for high load or high temperature test environment.

[0046] II. Resin-based friction material, composed of reinforcing fiber + resin + friction powder, high temperature resistance up to 350°C, good wear resistance, suitable for mechanical clutches or high temperature road simulation.

[0047] III. Paper-based friction material, containing carbon fiber + aramid + resin, stable friction coefficient, small thermal decay, fast recovery, suitable for tests with high consistency requirements.

[0048] IV. Carbon fiber composite material, containing carbon fiber + rubber + cork, high temperature resistance, low wear, low noise, suitable for precision testing or long-term use.

[0049] V. Ceramic-based friction material, high heat resistance, low wear, stable friction coefficient, suitable for extreme high temperature or high speed friction test scenarios such as simulating high speed brake working conditions.

[0050] The counterforce maintaining mechanism 400 extends in the horizontal direction, and the extension length is greater than the sum of the movement distance of the test base 200 during testing and the length of the test base 200. Specifically, the counterforce maintaining mechanism 400 includes a pressing plate 401 that is rollingly connected with the test base 200. The pressing plate 401 is provided with a counterweight. At least one rolling element 402 such as a ball is arranged between the pressing plate 401 and the test base 200. It can be understood that the surface of the pressing plate 401 facing the test base 200 is provided with a rolling groove, and the rolling element 402 moves in a fixed direction in the rolling groove, realizing the rolling connection between the pressing plate 401 and the test base 200. The pressing plate 401 is provided with a counterweight plate or a counterweight block as needed, which cooperates with the supporting leg 403 to balance the thrust of the pressure adjusting mechanism 700 to the counterforce maintaining mechanism 400. The pressing plate 401 can prevent the test device from overturning and from being in virtual contact with the test surface, and reduce the influence of the counterforce maintaining mechanism 400 on the test results.

[0051] In the present embodiment, the supporting leg 403 is fixed to the ground by a fastening element 404 such as a bolt, so that the supporting leg 403 can be repeatedly disassembled and assembled.

[0052] The pressure adjusting mechanism 700 comprises a hydraulic cylinder arranged in the vertical direction and a pressure head connected to the acting end of the hydraulic cylinder. The pressure head faces the counterforce maintaining mechanism 400. When the pressure adjusting mechanism 700 exerts a force on the counterforce maintaining mechanism 400, the test base 200 will be subjected to the counterforce of the counterforce maintaining mechanism 400.

[0053] Further, the embodiment also comprises a traction mechanism 300. The traction mechanism 300 is arranged to pull the friction plate 500 and the test base 200 in the horizontal direction. Specifically, the traction mechanism 300 comprises a winch 301 connected to the test base 200 and a water tank 302 arranged on the winch 301. The water tank 302 is provided with a water inlet 3021 and a water outlet 3022. The traction mechanism 300 provides pulling force for the test device, and the speed and pulling force are adjustable. The water tank 302 provides counterweight and humidifying water source for the traction mechanism 300.

[0054] Preferably, the traction mechanism 300 further comprises a sprayer 303 arranged in front of the water outlet 3022. The water tank 302 simultaneously provides water source for the sprayer 303. The sprayer 303 cleans the test area and adjusts the dry and wet state of the test area, solving the problems of manual cleaning and watering. The working principle of the sprayer 303 is as follows: high-pressure working fluid passes through the nozzle to generate high-speed jet, which sucks low-pressure fluid and discharges after mixing and pressurizing.

[0055] It should be noted that manual traction of the friction plate 500 and the test base 200 in the horizontal direction can also be selected, but generally traction by the traction mechanism 300 is selected. The pulling force of the traction mechanism 300 is controllable, and the digital closed loop of speed-force value is used to obtain more accurate data, more realistic working conditions, safer personnel, and lower cost test process.

[0056] Further, the embodiment also comprises a plurality of calibration blocks with different roughness. The calibration blocks are arranged to correct the test error of the road friction coefficient test device. Specifically, the calibration blocks are used to correct the error caused by the contact friction between the rolling element 402 and the pressure plate 401, the self-weight of the friction plate 500 and other factors.

[0057] The embodiment also provides a road surface friction coefficient testing system, which comprises a control module 100 and a road surface friction coefficient testing device connected with the control module 100. The control module 100 adopts a controller with a model of STM32. The control module 100 controls the traction mechanism 300 to spray air or water, and adjusts the traction force and the traction speed. The control module 100 controls the pressure adjusting mechanism 700 to adjust the pressure on the counterforce maintaining mechanism 400, thereby adjusting the contact pressure of the test base body 200 and the friction sheet 500 on the test area. Meanwhile, the control module 100 receives and processes the pressure information fed back by the pressure sensor 201, the tension information fed back by the tension sensor 202, the time information fed back by the timer 203 and the distance information fed back by the laser displacement sensor 204, and calculates the static friction coefficient and the dynamic friction coefficient according to the tension and the pressure, and generates a dynamic change curve of the dynamic friction coefficient with time, a dynamic change curve of the dynamic friction coefficient with distance and a dynamic change curve of the dynamic friction coefficient with tension.

[0058] It should be noted that if the pressure fed back by the pressure sensor 201 does not meet the design pressure, the control module 100 automatically controls the pressure adjusting mechanism 700 to adjust the pressure on the counterforce maintaining mechanism 400, thereby adjusting the contact pressure of the test base body 200 and the friction sheet 500 on the test area.

[0059] Further, the embodiment also comprises an energy storage mechanism 600. The energy storage mechanism 600 is arranged to store solar energy and convert the solar energy into electric energy required by the control module 100, the test base body 200, the traction mechanism 300 and the pressure adjusting mechanism 700. Specifically, the energy storage mechanism 600 can select a solar photovoltaic system, which comprises a solar cell assembly, a controller, a storage battery and an alternating current inverter. Under the light condition, the solar cell assembly generates a certain electromotive force, and a square array of solar cells is formed through series and parallel connection of the assembly, so that the square array voltage meets the requirement of the system input voltage. Then, the storage battery is charged through a charge-discharge controller, and the electric energy converted from the light energy is stored. The storage battery group provides input power for the inverter, and through the action of the inverter, the direct current is converted into alternating current and delivered to a power distribution cabinet for power supply through the switching action of the power distribution cabinet. The discharge condition of the storage battery group is controlled by the controller, so as to ensure the normal use of the storage battery.

[0060] In combination with Figure 3 and Figure 4 , the working principle of the present application is as follows:

[0061] S0, select a calibration block with a theoretical friction coefficient similar to that of the test area, and measure the maximum pulling force required to cause the test base 200 and the friction plate 500 to move relative to each other, and the pulling force required to maintain a uniform relative speed on the calibration block under test conditions, as well as the pressure on the pressure sensor 201, to obtain the friction coefficient of the calibration block under test conditions; according to the friction coefficient under test conditions and the theoretical friction coefficient, obtain the correction amount and input it into the control module 100;

[0062] S1, the control module 100 controls the pressure adjusting mechanism 700 to cooperate with the counterforce maintaining mechanism 400 to apply and maintain pressure on the test base 200, and the pressure sensor 201 records the pressure;

[0063] S2, the control module 100 controls the traction mechanism 300 to apply a pulling force to the test base 200 and the friction plate 500, and pulls the test base 200 and the friction plate 500 to move at a uniform speed in the horizontal direction, the pulling force sensor 202 records the pulling force, the laser displacement sensor 204 records the movement distance of the test base 200, and the timer 203 records the test time.

[0064] S3, calculate the static friction coefficient and the dynamic friction coefficient according to the pulling force and the pressure, and generate a dynamic change curve of the dynamic friction coefficient with time, a dynamic change curve of the dynamic friction coefficient with distance, and a dynamic change curve of the dynamic friction coefficient with pulling force.

[0065] S4, according to the correction amount and the static friction coefficient and the dynamic friction coefficient obtained in step S3, obtain the corrected static friction coefficient and the dynamic friction coefficient, that is, the static friction coefficient and the dynamic friction coefficient obtained in step S3 minus the correction amount are the corrected static friction coefficient and the dynamic friction coefficient, and generate a dynamic change curve of the corrected dynamic friction coefficient with time, a dynamic change curve of the corrected dynamic friction coefficient with distance, and a dynamic change curve of the corrected dynamic friction coefficient with pulling force.

[0066] S5, according to any one of the methods of the Laiyida criterion, quartile distance method and standard score method, the abnormal value of the corrected dynamic friction coefficient is removed, and the effective dynamic friction coefficient and the average value of the effective dynamic friction coefficient are obtained. Specifically, the Laiyida criterion (3σ criterion) is to assume that a set of test data only contains random errors, and the standard deviation is obtained by calculation and processing. According to a certain probability, an interval is determined, and it is considered that the error beyond this interval is not random error but gross error, and the data containing the error should be removed. The quartile distance method (IQR method) is to calculate the upper quartile (Q3) and lower quartile (Q1) of the data, and the data outside Q1-1.5IQR and Q3+1.5IQR is removed. The standard score method (Z-Score method) is to calculate the Z-Score (standard score) of each data point, and the data with Z-Score absolute value greater than 3 is regarded as abnormal value and removed, or a threshold is manually set to obtain the effective friction coefficient.

[0067] S6, the stability and uniformity of the effective dynamic friction coefficient are calculated and output according to the effective dynamic friction coefficient. The value for evaluating the stability and uniformity of the effective dynamic friction coefficient is standard deviation and coefficient of variation. The smaller the standard deviation, the more concentrated the data, and the better the stability of the effective dynamic friction coefficient; the larger the standard deviation, the more dispersed the data, and the poorer the stability of the effective dynamic friction coefficient. The smaller the coefficient of variation, the smaller the relative difference of the dynamic friction coefficient at different measurement points or different times, and the better the uniformity of the effective dynamic friction coefficient. The larger the coefficient of variation, the larger the relative difference of the dynamic friction coefficient at different measurement points or different times, and the poorer the uniformity of the effective dynamic friction coefficient.

[0068] In the description of the embodiments of the application, it should also be noted that, unless otherwise explicitly specified and limited, if the terms "arrangement", "connection" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0069] Obviously, the above embodiments are only examples for clear illustration, and are not limited to the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A road surface friction coefficient testing device characterized by, The road surface friction coefficient testing device comprises a friction plate (500), a test base (200) arranged above the friction plate (500), a counterforce maintaining mechanism (400) arranged above the test base (200), and a reflecting plate (205) fixed to the ground; the counterforce maintaining mechanism (400) is provided with supporting legs (403) fixed to the ground at two ends, and the upper part of the test base (200) is provided with a pressure adjusting mechanism (700); the friction plate (500) and the test base (200) are configured to slide relative to the counterforce maintaining mechanism (400); the upper part of the friction plate (500) is provided with a pressure sensor (201); one side of the test base (200) is provided with a tension sensor (202), and the other side of the test base (200) is provided with a laser displacement sensor (204); the test base (200) is provided with a timer (203); and the reflecting plate (205) is arranged to reflect the light signal emitted by the laser displacement sensor (204); The counterforce maintaining mechanism (400) extends in the horizontal direction, and the extension length is greater than the sum of the movement distance of the test base (200) and the length of the test base (200) during testing; the counterforce maintaining mechanism (400) comprises a pressing plate (401) in rolling connection with the test base (200); and the pressing plate (401) is provided with a counterweight; The pressure adjusting mechanism (700) comprises a hydraulic cylinder arranged in the vertical direction and a pressure head connected with the acting end of the hydraulic cylinder; and the pressure head faces the counterforce maintaining mechanism (400); The road surface friction coefficient testing device further comprises a traction mechanism (300); the traction mechanism (300) is arranged to pull the friction plate (500) and the test base (200) to move in the horizontal direction; the traction mechanism (300) comprises a winch (301) connected with the test base (200) and a water tank (302) arranged on the winch (301); and the water tank (302) is provided with a water inlet (3021) and a drain outlet (3022); The road surface friction coefficient testing device further comprises a plurality of calibration blocks with different roughness degrees; the calibration blocks are arranged to correct the test error of the road surface friction coefficient testing device.

2. The road surface friction coefficient testing device according to claim 1, characterized in that, The traction mechanism (300) further comprises an ejector (303) arranged in front of the drain outlet (3022).

3. A road surface friction coefficient testing system characterized by, The road surface friction coefficient testing device comprises: a control module (100); The road surface friction coefficient testing device according to claim 1 or 2 is connected with the control module (100).

4. A method of testing the coefficient of friction of a road surface, characterized by, The road surface friction coefficient testing system according to claim 3 comprises the following steps: S1, the control module (100) controls the pressure adjusting mechanism (700) to cooperate with the counterforce maintaining mechanism (400) to apply pressure to the test base (200) and maintain the pressure, and the pressure sensor (201) records the pressure; S2, the control module (100) controls the traction mechanism (300) to apply a pulling force to the test substrate (200) and the friction plate (500), pulls the test substrate (200) and the friction plate (500) to move at a constant speed in the horizontal direction, the pulling force sensor (202) records the pulling force, the laser displacement sensor (204) records the moving distance of the test substrate (200), and the timer (203) records the test time; S3, calculate the static friction coefficient and the dynamic friction coefficient according to the pulling force and the pressure, and generate the dynamic change curve of the dynamic friction coefficient with time, the dynamic change curve of the dynamic friction coefficient with distance, and the dynamic change curve of the dynamic friction coefficient with pulling force.

5. The method of testing the coefficient of friction of a road surface of claim 4 wherein, Also includes: Step S0 before step S1: Select a calibration block with a theoretical friction coefficient close to the test area, measure the maximum pulling force required to make the test substrate (200) and the friction plate (500) about to produce relative motion and the pulling force required to produce and maintain relative uniform motion on the calibration block under test conditions, and the pressure received by the pressure sensor (201), obtain the friction coefficient of the calibration block under test conditions; according to the friction coefficient under test conditions and the theoretical friction coefficient, obtain the correction amount and input it into the control module (100); And Step S4: According to the correction amount and the static friction coefficient and the dynamic friction coefficient obtained in step S3, obtain the corrected static friction coefficient and the dynamic friction coefficient, and generate the dynamic change curve of the corrected dynamic friction coefficient with time, the dynamic change curve of the corrected dynamic friction coefficient with distance, and the dynamic change curve of the corrected dynamic friction coefficient with pulling force.

6. The method of testing the coefficient of friction of a road surface of claim 5 wherein, Also includes step S5: According to any one of the methods of Lyapunov criterion, quartile distance method and standard score method, the abnormal value of the corrected dynamic friction coefficient is removed to obtain the effective dynamic friction coefficient and the average value of the effective dynamic friction coefficient; And step S6: Calculate and output the numerical value of evaluating the stability and uniformity of the effective dynamic friction coefficient according to the effective dynamic friction coefficient.

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