JPH02284020A - Road surface measuring method - Google Patents

Abstract

PURPOSE:To take a measurement at a normal travel speed by processing the outputs of noncontact laser displacement gages and a noncontact optical speed indicator while making a measurement vehicle travel. CONSTITUTION:The output signals of the three noncontact laser displacement gages 2 to 4 are inputted to an A/D converter 8 through a displacement gage processor 7 mounted on the measurement vehicle 1. Further, the output signal of the noncontact optical displacement gage 6 is inputted to the converter 8 through a speed indicator processor 9. Then the output signal of the converter 8 is inputted to a personal computer 10 and measurement data are stored on a floppy disk or printed out. For the purpose, the measurement vehicle 1 which is traveling on the road to be measured irradiates the measured road surface W with laser light from the displacement gage 2 to 4 and photodetects its reflected light and the obtained road surface-displacement data are processed to measure the unevenness-profile of the road surface W.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a road surface measurement method for measuring the unevenness profile of a road surface.

(Prior Art) The surface of a road, not only an unpaved road but also a paved road, is not completely smooth and has various unevenness. As a result, vehicles traveling on the road are subjected to complex forces that depend on the shape of the road's unevenness and the speed at which they are traveling. If we divide these forces into components in the vertical, longitudinal, and horizontal directions of the zero-motion vehicle, we get
In particular, vertical force has a close relationship with vibration ride comfort and cargo damage. Furthermore, it is the biggest cause of deformation and destruction of the vehicle body. Therefore, understanding the degree of unevenness of the road surface is essential for the development of automobiles.

Conventionally, as a method to calculate the total n1 of the uneven profile of the road surface,
A method using a multi-wheel measuring vehicle and a method using a servo vibration meter are widely known. The method of using a multi-wheel measurement vehicle is to set a reference line using the average of multiple links and measure the unevenness of the road surface by the movement of a single wheel, but the device is complicated, the measurement speed is slow, and it takes a long time. It is not suitable for measuring distances on road surfaces.

In addition, the method of using a servo vibration meter is to install a meter on the measuring vehicle,
In this method, a p1 wheel is attached, the relative distance between the measuring vehicle and the road surface is determined by the movement of the measuring wheel, the vertical displacement of the measuring vehicle is determined by double integration of acceleration, and the unevenness of the road surface is determined by subtracting these values. Although the measurement speed has been improved to some extent, the total CJ
Since the wheels vibrate when they come into contact with the road surface, consideration must be given to resonance and other issues.

In addition, in order to solve the above-mentioned problems, a non-contact laser displacement meter was used instead of the servo vibration meter with the measuring wheels, and this was mounted on a measuring vehicle and was used while driving on the road to be measured. A method is also known in which a laser beam is irradiated onto a road surface and the uneven profile of the road surface is measured by the beam reflected from the road surface.

(Problem to be Solved by the Invention) However, as mentioned above, even if a non-contact laser displacement meter is mounted on a measurement vehicle and the measurement is carried out while the measurement vehicle is running, it is difficult to use a single non-contact laser displacement meter. Because of the measurement, if the vehicle body bounces due to input from the road surface, a measurement error will occur.

Therefore, it is necessary to drive on the same road on the same wave meter side road and take measurements to improve accuracy. In addition, since the running speed of the measurement vehicle is limited and measurements cannot be made at normal running speeds, when measuring a road surface such as an expressway, the vehicle can travel together with general vehicles for a total of 7111km.

This invention was made with attention to the above-mentioned circumstances, and its purpose is to improve the reliability of measurement data that can be calculated at normal driving speeds and that can be accurately measured even when the vehicle bounces. The object of the present invention is to provide a road surface measurement method that can improve road surface measurement and quickly measure the road surface.

[Structure of the invention] (Means and effects for solving the problem) This invention has the following features:
In order to achieve the above object, three or more non-contact laser displacement meters are arranged in a straight line along the longitudinal direction of the vehicle body at different intervals, and a non-contact optical speed meter is installed on the measurement vehicle. , while running the measurement vehicle, calculate and process the outputs from the non-contact laser displacement meter and the non-contact optical speed meter, and set the three non-contact laser displacement meters as one set,
The purpose of the wave meter is to measure the uneven profile of the road surface.

Here, to explain the measurement principle with reference to FIG. 1, 1 is a total of δ11 cars, and A sensor, C sensor, and B sensor as non-contact laser displacement meters are arranged in a straight line along the longitudinal direction of this car body. are arranged in this order, between the A sensor and B sensor, and between the LSA sensor and C sensor, and C
The distance between the sensor and the B sensor is L2.

A; (A sensor output) B: (B sensor output) C: (C sensor output) f (X) : (road surface function) g (X) : (measurement system output) and g
When (X) is expressed using f (X),... (1
) On the other hand, if g (X) is expressed using the sensor output, (1)
From the formula, if we Fourier transform the relationship between g (X) and f (X, ), we get G (ω) - F (ω) × [1 - L7 /LXE
XP (-j ωL1) L+/LXEX
P(jωL2)]−F(ω)×H(ω) F(ω)−G(ω)/H(ω) F(ω) represents the measured road surface in the frequency domain. The road surface profile can be reproduced by expressing F(ω) in the time domain f (X) using inverse Fourier transform.

(Example) Hereinafter, each embodiment of the present invention will be described based on the drawings.

Figures 2 to 4 show the first embodiment, in which the measuring vehicle 1
is provided with three non-contact laser displacement meters 2.3 and 4, as well as a non-contact optical velocity meter 6. The non-contact laser displacement gauges 2.3 and 4 are the measurement vehicle 1.
are arranged in a straight line along the front-rear direction. Then, the distance between non-contact laser displacement gauges 2 and 3 is set to L+ 3 and 4.
Let L2 be the interval between L2 and L2.

The output signals from the three non-contact laser displacement meters 2.3 and 4 are total nl+displacement meter processor 7 mounted on the vehicle 1.
The signal is input to the A/D converter 8 via the A/D converter 8.

Further, the output signal from the non-contact optical displacement meter 6 is input to the A/D converter 8 via the velocity processor 9. The output signal from the A/D converter 8 is input to a personal computer 10, and the measurement data is saved on a floppy disk or printed.

Therefore, while the measuring vehicle 1 was traveling on the wave meter al11 road,
Measured road surface W from each non-contact laser displacement meter 2.3 and 4
By irradiating a laser beam onto the road surface and receiving the reflected light, the i4-obtained road surface displacement data is processed using the routine shown in the flowchart shown in FIG. .

That is, the road surface displacement data output from each non-contact laser displacement meter 2.3 and 4 is output as a system output g (X) EE in step 1, and the vehicle speed data output from the non-contact optical speed meter 5 in step 2. Based on: l'
Calculate i11 time and ;1' distance measurement.

Furthermore, in step 3, Fourier transform [g (ω)] is performed,
Considering the system transfer function H(ω) in the frequency range, F(ω)−G(ω)/H(ω) is determined in step 4. Furthermore, by inputting the power spectral density S (n) and performing an inverse Fourier transform [F (ω) in step 5, the road surface profile f (X) can be obtained in step 6.

That is, F(ω) represents the measured road surface in the frequency domain. F(ω) is transformed into time domain f by inverse Fourier transform.
By representing it with (X), the road surface profile can be reproduced.

In this first embodiment, non-contact laser displacement meters 2 and 3
The distance between 3 and 4 is L21, L l
- When set to L and -L, the transfer function becomes as shown in FIG. 5(a), and at point a, the transfer function becomes zero and there is no output as a system. Therefore, the range that can be continuously measured is the range from point b to point C.

In other words, with three non-contact laser displacement meters 2.3 and 4,
In the case of L, -L2, the system periodically has unmeasurable road surface wavelengths.

However, with three non-contact laser displacement meters 2.3 and 4,
When L, ≠ L2, there is no part of the transfer function where it is zero, and as shown in FIG. 5(b), the range that can be continuously measured, from point b to point C, is expanded.

Figure 6 shows the second embodiment, in which four non-contact laser displacement meters 2, 3, 4 and 5 are arranged, and the distance between them is L2, L, and >L2>L3. 2 and 1 Therefore, 3 units are set as 11'■ (2, 3, 4) (2, 4
, 5) (3, 4, 5) (2, 3, 5).

In this way, by using four non-contact laser displacement meters, it is the same as measuring with four different systems.
This corresponds to a total of 4 p1s performed four times on the same road surface under the same conditions in one run. Therefore, it is possible to significantly shorten the measurement time, and the total viscosity is improved by 11111.
13. Improves reliability.

[Effects of the Invention] As explained above, according to the present invention, three or more non-contact laser displacement meters are arranged on a measurement vehicle in a straight line along the longitudinal direction of the vehicle body at different intervals. At the same time, a non-contact optical speed meter is installed, and while the A11J car is running, the outputs from the non-contact laser displacement meter and the non-contact optical speed meter are processed, and the three non-contact laser displacement meters are combined into one set. Since the wave meter measures the uneven profile of the Ml road surface, it can be measured at normal driving speed, and it can be accurately calculated regardless of the bouncing of the vehicle body, which improves the reliability of the total data. This has the effect of being able to improve the performance and quickly measure it.

[Brief explanation of drawings]

FIG. 1 is a side view of a measurement vehicle for explaining the invention in detail, FIGS. 2 to 5 show a first embodiment of the invention, and FIG. 2 is a side view of the measurement vehicle; Figure 3 is a block diagram of the measurement system, Figure 4 is a flowchart, Figure 5 (a)
(b) is a graph showing the relationship between road surface wavelength and amplitude (transfer function of the system), and FIG. 6 is a side view of a measuring vehicle showing a second embodiment of the present invention. 1... Measuring vehicle, 2.3.4.5... Non-contact laser displacement meter, 6... Non-contact optical speed meter. ■Applicant's agent

Claims (1)

[Claims] Three or more non-contact laser displacement gauges are arranged in a straight line along the longitudinal direction of the vehicle body at different intervals on the measuring vehicle, and a non-contact optical speed meter is installed, and while the measuring vehicle is running, A road surface measurement method characterized in that the outputs from the non-contact laser displacement meter and the non-contact optical speed meter are processed, and the three non-contact laser displacement meters are used as one set to measure the uneven profile of the road surface to be measured. .