A method for calculating road surface roughness based on real-time vehicle speed

Abstract

The present invention discloses a method for calculating road surface roughness based on real-time vehicle speed. This method includes equipment installation, data collection, speed determination, state value calculation, and International Roughness Index (IRI) calculation. This method is automated and adapts to vehicle speed. It calculates the corresponding International Roughness Index (IRI) based on real-time vehicle speed, significantly improving detection accuracy compared to the roughness value at an ideal vehicle speed.

Description

Technical Field

[0001] The present invention relates to the technical field of road surface smoothness measurement, and in particular to a method for calculating road surface smoothness based on real-time vehicle speed. Background Art

[0002] In recent years, with the continuous development of science and technology, automated, non-destructive, and intelligent road inspection technologies have developed rapidly and gained widespread adoption and application. Road surface roughness is a crucial indicator in rural road inspection. It represents the vertical deviation of the road surface from the ideal plane. This deviation affects vehicle dynamics, ride quality, dynamic loads on the road surface, and drainage. An uneven road surface not only affects the safety and comfort of passengers and drivers, but also reduces vehicle operating costs and accelerates road structural damage. Therefore, the measurement and calculation of roughness indicators are particularly important.

[0003] Currently, the main roughness evaluation indicators used in my country's highway standards include: the maximum clearance Δh (mm) measured with a three-meter ruler, the standard deviation of road surface roughness σ (mm), and the internationally recognized International Roughness Index (IRI) (m / km). Currently, the International Roughness Index (IRI) is mostly used to evaluate road surface roughness in my country. The IRI uses a quarter-car model, running steadily at 80 km / h, to calculate the ratio of the total displacement (in meters) of the standard vehicle suspension to the distance traveled (in kilometers).

[0004] The present invention takes into account the fact that the vehicle speed cannot be maintained at 80 km / h in actual conditions. For example, during the vehicle acceleration phase and deceleration due to traffic conditions, the vehicle speed will have a certain impact, which in turn affects the test results. Therefore, based on the vehicle-mounted laser smoothness meter flatness test method in the "Highway Roadbed and Pavement Field Test Specification" (JTG 3450-2019), the present invention proposes a road surface smoothness algorithm and device based on real-time vehicle speed, ensuring the accuracy of the smoothness calculation and providing a theoretical basis for road managers to make decisions. Summary of the Invention

[0005] In order to solve the problems in the background technology, the present invention provides a road surface roughness calculation method based on real-time vehicle speed. The method has the characteristics of automation, can adapt to the vehicle speed, and calculate the corresponding international roughness value IRI according to the real-time vehicle speed. Compared with the flatness value at the ideal vehicle speed, its detection accuracy is greatly improved.

[0006] The present invention provides a method for calculating road surface smoothness based on real-time vehicle speed, comprising the following steps:

[0007] Step 1: Equipment installation: Install the laser displacement sensor, accelerometer, mileage encoder, on-board industrial computer, flatness data acquisition card, and Beidou GNSS device on the corresponding positions of the vehicle platform, and connect the laser displacement sensor, accelerometer, mileage encoder, flatness data acquisition card, and Beidou GNSS device to the on-board industrial computer respectively;

[0008] Step 2: Data collection: Calculate the flatness index IRI within 10m with a distance of 10m, and obtain the elevation data (y1, y2, y3, ..., y 100 ), and the speed value corresponding to each elevation value (v1, v2, v3, ..., v 100 ), and calculate the slope value k between the previous state and the next state i ';

[0009] Step 3: Speed ​​determination: According to the current speed V of the vehicle platform, determine the corresponding state transfer matrix ST at this speed. i PR i , combined with the slope value k i 'Calculate the state value in this state and use it as the initial value of the next state;

[0010] Step 4: Calculate the state value. The vehicle platform enters the next state and similarly determines the speed V of the current state. The state transfer matrices ST and PR of the current state are determined based on the speed V. The state value of the current state is solved, and the iteration is repeated until the final state is reached, at which point the calculation ends.

[0011] Step 5: Calculate the International Roughness Index (IRI): Calculate the International Roughness Index (IRI) through the state value in each state.

[0012] In a preferred embodiment of the road surface roughness calculation method based on real-time vehicle speed provided by the present invention, in the step one, a single laser displacement sensor and a single accelerometer are respectively installed in the middle position of the bottom of the vehicle platform, and one group is installed on each of the left and right sides, with an installation height of 300 mm; the mileage encoder is installed at the left wheel of the vehicle platform, and the Beidou GNSS device is installed at the front center position of the roof of the vehicle platform; the on-board industrial computer and the flatness data acquisition card are placed in the trunk cabinet of the vehicle platform, and the laser displacement sensor, the accelerometer, the mileage encoder, the flatness data acquisition card and the Beidou GNSS device are respectively connected to the on-board industrial computer through cables.

[0013] Compared with the existing technology, the road surface roughness calculation method based on real-time vehicle speed provided by the present invention has the following beneficial effects:

[0014] 1. Conventional algorithms for calculating roughness are all calculated under the condition of an ideal vehicle speed of 80 km / h. The algorithm provided by the present invention can adapt to the vehicle speed and calculate the corresponding international roughness value IRI based on the real-time vehicle speed. Compared with the flatness value at the ideal vehicle speed, its detection accuracy is greatly improved.

[0015] 2. The method of measuring flatness is usually to use a three-meter ruler to determine the maximum gap. This method requires road closure, consumes a lot of manpower and material resources, has a high risk factor, and has a low degree of automation. The algorithm provided by the present invention can realize automatic analysis and calculation of flatness data. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0017] Figure 1 This is a flow chart of a method for calculating road surface smoothness based on real-time vehicle speed provided by the present invention;

[0018] Figure 2 This is a structural block diagram of a device for calculating road surface roughness based on real-time vehicle speed provided by the present invention;

[0019] Figure 3 This is a schematic diagram of a standard road section used in testing the road surface smoothness calculation method based on real-time vehicle speed of the present invention. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] The present invention uses the data model of the International Roughness Index to calculate the road surface roughness IRI. First, the International Roughness Index uses a quarter-car model. By calculating the longitudinal section curve, the total absolute displacement of the vehicle system after traveling a certain distance is obtained. The total displacement is then compared with the total distance traveled by the vehicle to obtain the IRI, that is:

[0022]

[0023] The exact solution is calculated using the state transfer matrix method and described by four state quantities (z1, z2, z3, z4). First, the state quantities are initialized, and the average slope of the first 11 meters is used as the initial value of the first state, that is:

[0024]

[0025] where y d Indicates the elevation value at 11m.

[0026] Solve the recursive equation from the second state to the nth state:

[0027] in

[0028] Convert formula (1) into:

[0029]

[0030] The present invention uses different state transfer matrices at different vehicle speeds to improve the calculation accuracy of the roughness index IRI. Figure 1 and Figure 2 ,in, Figure 1 This is a flow chart of a method for calculating road surface smoothness based on real-time vehicle speed provided by the present invention; Figure 2 The present invention provides a block diagram of a device for calculating the road surface roughness based on real-time vehicle speed. The method for calculating the road surface roughness based on real-time vehicle speed includes the following steps:

[0031] Step 1: Equipment installation: Install the laser displacement sensor 11, accelerometer 12, mileage encoder 13, on-board industrial computer 14, flatness data acquisition card 15, and Beidou GNSS device 16 on corresponding positions on the vehicle platform, and connect the laser displacement sensor 11, accelerometer 12, mileage encoder 13, flatness data acquisition card 15, and Beidou GNSS device 16 to the on-board industrial computer 14 respectively;

[0032] Specifically, a single laser displacement sensor 11 and a single accelerometer 12 are respectively installed in the middle position of the bottom of the vehicle platform, and a group is installed on each of the left and right sides, with an installation height of 300 mm; the mileage encoder 13 is installed at the left wheel of the vehicle platform, the Beidou GNSS device 16 is installed at the front center position of the roof of the vehicle platform, the on-board industrial computer 14 and the flatness data acquisition card 15 are placed in the trunk cabinet of the vehicle platform, and the laser displacement sensor 11, the accelerometer 12, the mileage encoder 13, the flatness data acquisition card 15 and the Beidou GNSS device 16 are respectively connected to the on-board industrial computer 14 through cables;

[0033] Step 2: Data collection: Take 10m as the distance, calculate the flatness index IRI within 10m, and obtain the elevation data (y1, y2, y3, ..., y1) collected by the laser displacement sensor 11 at intervals of 100mm through the flatness data acquisition card 15. 100 ), and the speed value corresponding to each elevation value (v1, v2, v3, ..., v 100 ), and calculate the slope value k between the previous state and the next state i ';

[0034] Specifically, k i '=(y i -y i-1 ) / 0.1;

[0035] Step 3: Speed ​​determination: According to the current speed V of the vehicle platform, determine the corresponding state transfer matrix ST at this speed. i PR i , combined with the slope value k i 'Calculate the state value in this state and use it as the initial value of the next state;

[0036] Specifically, if the current speed is (0, 20] km / h, the corresponding state transfer matrix at this speed is ST=ST1, PR=PR1; if the current speed is (20, 40] km / h, the corresponding state transfer matrix at this speed is ST=ST2, PR=PR2; if the current speed is (40, 60] km / h, the corresponding state transfer matrix at this speed is ST=ST3, PR=PR3; if the current speed is (60, 80] km / h, the corresponding state transfer matrix at this speed is ST=ST4, PR=PR4; if the current speed is (80, 100] km / h, the corresponding state transfer matrix at this speed is ST=ST5, PR=PR5;

[0037] The state transition matrix used in the present invention is as follows:

[0038] When V∈(0,20]km / h,

[0039]

[0040] When V∈(20,40]km / h,

[0041]

[0042] When V∈(40,60]km / h,

[0043]

[0044] When V∈(60,80]km / h,

[0045]

[0046] When V∈(80,100]km / h,

[0047]

[0048] After determining the state transfer matrix, the state transfer matrix, slope value k i Substitute into the recursive equation (3), solve the next state value (z1, z2, z3, z4) of this state, and use it as the initial value of the next state;

[0049] Step 4: Calculate the state value. When the vehicle platform enters the next state, the speed V of the current state is determined. The state transfer matrices ST and PR of the current state are determined according to the speed V. The state values ​​(z1, z2, z3, z4) in the current state are solved. The calculation is then terminated after the final state is reached.

[0050] Step 5: Calculate the International Roughness Index (IRI): Calculate the International Roughness Index (IRI) through the state value in each state;

[0051] Specifically, the state value (z1, z2, z3, z4) in each state is substituted into formula (4) to obtain the final international roughness index IRI.

[0052] Experimental example

[0053] The smoothness algorithm of the present invention was verified on a standard road section. The smoothness calculation and verification of the standard road section were carried out using three different methods: manual measurement, ordinary international roughness IRI algorithm, and the smoothness algorithm of the present invention. The standard road section is shown in the attached figure. Figure 3As shown, the standard road section is 700 meters long. By placing different groups of test blocks, the flatness value of the road section is changed to make the flatness value distribution wider. The artificial value is measured every 100 meters with a digital level. By testing the three methods, the flatness values ​​measured by the corresponding methods are obtained. The results are as follows:

[0054]

[0055] Through testing of this road section, it was found that in the first 100m (acceleration section) and the last 100m (deceleration section), the difference between the ordinary IRI algorithm and the manual measurement value was relatively large. The flatness IRI value obtained by the algorithm of the present invention had little effect during acceleration and deceleration, and both met the correlation of 0.99. In addition, the data accuracy in other sections was very high, indicating the effectiveness of the algorithm of the present invention.

[0056] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for calculating road surface roughness based on real-time vehicle speed, characterized in that: The following steps are involved: Step 1: Equipment installation: Install the laser displacement sensor, accelerometer, mileage encoder, on-board industrial computer, flatness data acquisition card, and Beidou GNSS device on the corresponding positions of the vehicle platform, and connect the laser displacement sensor, accelerometer, mileage encoder, flatness data acquisition card, and Beidou GNSS device to the on-board industrial computer respectively; Step 2: Data collection: Calculate the flatness index IRI within 10m with a distance of 10m, and obtain the elevation data (y1, y2, y3, ..., y 100 ), and the speed value corresponding to each elevation value (v1, v2, v3, ..., v 100 ), and calculate the slope value k between the previous state and the next state i '; Step 3: Speed ​​determination: According to the current speed V of the vehicle platform, determine the corresponding state transfer matrix ST at this speed. i PR i , combined with the slope value k i 'Calculate the state value in this state and use it as the initial value of the next state; If the current state speed is (0, 20] km / h, the corresponding state transfer matrix at this speed is ST=ST1, PR=PR1; if the current state speed is (20, 40] km / h, the corresponding state transfer matrix at this speed is ST=ST2, PR=PR2; if the current state speed is (40, 60] km / h, the corresponding state transfer matrix at this speed is ST=ST3, PR=PR3; if the current state speed is (60, 80] km / h, the corresponding state transfer matrix at this speed is ST=ST4, PR=PR4; if the current state speed is (80, 100] km / h, the corresponding state transfer matrix at this speed is ST=ST5, PR=PR5; Among them, the state transfer matrix is ​​as follows: When V∈(0,20]km / h, When V∈(20,40]km / h, When V∈(40,60]km / h, When V∈(60,80]km / h, When V∈(80,100]km / h, Step 4: Calculate the state value. The vehicle platform enters the next state and similarly determines the speed V of the current state. The state transfer matrices ST and PR of the current state are determined based on the speed V. The state value of the current state is solved, and the iteration is repeated until the final state is reached, at which point the calculation ends. Step 5: Calculate the International Roughness Index (IRI): Calculate the International Roughness Index (IRI) through the state value in each state.

2. The method for calculating road surface roughness based on real-time vehicle speed according to claim 1, characterized in that: In the step one, a single laser displacement sensor and a single accelerometer are respectively installed in the middle position of the bottom of the vehicle platform, and one group is installed on each side, with an installation height of 300 mm; the mileage encoder is installed at the left wheel of the vehicle platform, and the Beidou GNSS device is installed at the front center position of the roof of the vehicle platform. The on-board industrial computer and the flatness data acquisition card are placed in the trunk cabinet of the vehicle platform, and the laser displacement sensor, the accelerometer, the mileage encoder, the flatness data acquisition card and the Beidou GNSS device are respectively connected to the on-board industrial computer through cables.

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