JP2000131043A - Road surface roughness measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a road surface roughness measuring system in which a measuring circle on a road surface for measuring the coefficient of kinetic friction is divided into a plurality of sections and roughness is measured in each direction at the same section as the measuring position of the coefficient of kinetic friction. SOLUTION: A frame 32 having a plurality of legs 31 being set on a road surface G is provided and a rotary shaft 45 extending vertically is provided on the frame 32. The rotary shaft 45 is provided with a rotary encoder 44 and a rotary plate 50, respectively, at the upper and lower ends thereof. Furthermore, a geared motor 39 for driving the rotary shaft 45 through gears 41, 41a is provided and a laser displacement gauge 51 is fixed to the rotary plate 50. The laser displacement gauge 51 is disposed to measure the displacement along a coefficient of kinetic friction measurement circle of a rotary coefficient of kinetic friction measuring nit when the rotary plate 50 turns. The measurement circle is divided into a plurality of sections and pavement roughness is calculated for every section based on the signals from the laser displacement gauge 51 and the rotary encoder 44.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road surface roughness measuring apparatus for measuring roughness at the same position as that of a road friction coefficient measured by a rotary dynamic friction coefficient measuring device.

[0002]

2. Description of the Related Art Conventionally, various techniques for measuring the coefficient of kinetic friction on a road surface are known, and in these techniques, a measuring device is towed by a tractor (towing vehicle) or the like to separately measure roughness and a coefficient of kinetic friction. Was. However, the measured value of the coefficient of kinetic friction is generally liable to be deviated by a measuring device, and in order to unify the deviation, a relationship with a road surface roughness is determined, thereby determining an International Friction Index (IFI) value. I have.

[0003] For this purpose, it is necessary to measure the roughness and the coefficient of dynamic friction at the same location on the road surface, and it is quite difficult to measure these two values at the same location.

[0004] Regarding the measurement of the dynamic friction coefficient, the present applicant discloses a technique relating to a rotary type dynamic friction coefficient measuring apparatus in Japanese Patent Publication No. 3-10062. However, this technique measures the dynamic friction coefficient of a road surface in a circular shape, and does not measure the roughness. To determine the IFI value, a device for measuring the roughness at the same position is further required. Therefore, there has been a demand for a device capable of measuring road surface roughness in detail by further dividing into a plurality of locations on the same locus as the measurement circle of the rotary type dynamic friction coefficient measuring device.

[0005]

SUMMARY OF THE INVENTION The present invention addresses the above problems and divides a measurement circle on a road surface for measuring a dynamic friction coefficient with a rotary type dynamic friction coefficient measuring device into a plurality of points, and determines a measurement position of the dynamic friction coefficient. It is an object of the present invention to provide a road surface roughness measuring device for measuring roughness in the same direction in each direction.

[0006]

According to the present invention, there is provided a road surface roughness measuring device used in combination with a rotary dynamic friction coefficient measuring device, the frame having a plurality of legs for installation on a road surface. And a rotary shaft extending in the vertical direction is provided on the frame body, a rotary encoder is mounted on the upper end of the rotary shaft, and a rotary plate is mounted on the lower end, and a motor with a speed reducer that drives the rotary shaft via gears. Provided, a laser displacement gauge is attached to the rotating plate, and the laser displacement meter is installed so that the rotary dynamic friction coefficient measuring device measures the dynamic friction coefficient along a measurement circle by measuring the dynamic friction coefficient by rotation of the rotating plate. It has a function of dividing the measurement circle into a plurality of parts and calculating the road surface roughness of each divided section based on signals from the laser displacement meter and the rotary encoder.

According to the road surface roughness measuring device of the present invention, the device is installed at the same position as the dynamic friction coefficient measuring position on the road surface by the rotary dynamic friction coefficient measuring device, and is rotated along the same locus to measure the road surface roughness. I do. In the measurement, the distance from the measurement circle is measured by a laser displacement meter attached to a rotary plate rotated by a motor with a speed reducer according to a sample signal of a rotary encoder, and roughness is obtained. Then, the measurement circle is divided into a plurality of circles and output as, for example, MPD values for each of the divided sections.

Therefore, the roughness data in a plurality of directions and the dynamic friction coefficient at the same location can be measured, and more detailed analysis and research can be performed using the more detailed road surface data.

In the practice of the present invention, if the dynamic friction coefficient is measured first, rubber or the like may adhere to the road surface or become wet with water. Therefore, it is preferable to measure roughness first.

In the practice of the present invention, the road surface roughness can be measured over the entire circumference.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 and 2, a roughness measuring device generally indicated by a reference symbol A is a plurality of (four in the illustrated example) legs 3 made of an elastic body to be installed on a road surface G at a lower portion.
The frame 32 is provided with a square frame 32 having a number 1. The support plate 34 is supported by the columns 33 at both ends of the frame 32 above the frame 32, and is fixed with screws 35. In addition, the reference symbol R indicates a rib provided upright on both edges of the support plate 34.

A first substrate 37 is mounted on the support plate 34 via first supporting legs 36, and a motor 39 with a speed reducer 38 is mounted on the first substrate 37.
The speed reducer 38 has a reduction ratio of, for example, about 1/200, and a first gear 41 is attached to the output shaft 40.

A second board 43 is mounted in parallel with these via a second support leg 42, and a rotary encoder 44 is mounted on the board 43. A second gear 41a meshing with the first gear 41 is attached to a rotation shaft 45 of the rotary encoder 44, and a bearing 47 held by a bearing bracket 46 is provided below the second gear 41a.
The rotating plate 50 is fixed to the lower end of the rotating plate 50 via a bracket 49.

A laser head 51 of a laser displacement gauge is attached to the rotating plate 50. The laser head 51 is a known laser head itself. The laser light L1 emitted from the light emitting element is reflected on the road surface G, and a part L2 of the reflected light is received by the light receiving element. This is to find the distance.

The measurement circle P on which the rotating plate 50 is rotated about the rotation axis 45 and the laser head 51 irradiates the road surface with the laser beam L1 coincides with the dynamic friction coefficient measuring position of the rotary dynamic friction coefficient measuring device. It is set as follows.

On the other hand, as shown in FIG. 3, the electric circuit outputs the output of the laser head 51 via the amplifier unit 60 to the A / A.
D converter 61 and the rotary encoder 4
4 is also connected to the A / D converter 61, and is further connected to the personal computer 62 from the A / D converter 61. In addition, a battery (12 V) for an automobile is used as these power sources.

As shown in FIG. 5, the circumference of the measurement circle P is divided into eight sections a to h, and an MPD (Mean Profile Depth) is calculated for each section. Of running direction X from the average of
PD is calculated from the average of points c and g by M
It has a function of calculating the MPD in the direction of 45 degrees in the running direction from the PD or the average of the points b and f and the average of the points d and h. Of course, it is also possible to calculate the entire MPD by taking the average of the sections a to h.

The roughness measurement by the road surface roughness measuring apparatus of the present invention is performed prior to the measurement of the dynamic friction coefficient. That is, first, the road surface roughness measuring device A is installed on the road surface to measure the roughness of the road surface, then the rotary dynamic friction coefficient measuring device is installed at the same position, and both are rotated along the same locus, and the surface at the same position is rotated. The roughness and the dynamic friction coefficient are measured, and the IFI value is calculated from the relationship between the road surface roughness and the dynamic friction coefficient.

As shown in FIG. 6, the measurement of the MPD in each running direction is performed by inputting the signal of the light receiving element of the laser head 51 rotating in step S1 to the amplifier unit 60 and converting the signal to a voltage proportional to the distance from the road surface, as shown in FIG. It is converted and input to the A / D converter 61. On the other hand, the sampling signal from the rotary encoder 44 is also input to the A / D converter 61 (step S2), and the signal of the laser head 51 is sampled by this sampling signal, output as a digital signal, and stored in the personal computer 62. (Step S3). Then, recording is performed for each of the divided measurement sections (step S4), and the personal computer 62 calculates the MPD representing the surface roughness of each section from the stored data (step S4).
5), and the result is output.

FIG. 4 shows an example of this result. In the figure, the horizontal axis represents the length (the arc length of the locus circle P),
Symbol L is a sampling length. The vertical axis indicates the distance from the laser head 51, the symbol E indicates the upper limit of the measurement range M of the laser head, and H indicates the road surface level.

In this way, the personal computer 62 calculates the regression line H1 from the value obtained by measuring the road surface unevenness state F with the laser displacement meter with respect to the sampling length L, and subtracts the highest peak level H2 from the H1. MPD is calculated. The position H of the leg 31 is the position of the laser head 51 of the laser displacement meter.
All of the irregularities within the range of the measurement range M are set.

[0022]

As described above, according to the present invention, the road surface roughness at the same position as the measured circle can be measured in a single operation in a plurality of directions with respect to the traveling direction by combining with a rotating dynamic friction coefficient measuring device. The result is output, for example, on a personal computer. Therefore, the IFI value of the road surface can be determined in detail from the measured values of the coefficient of dynamic friction and the roughness at the same position, and can be effectively used for research on tire slippage of automobiles, aircraft, and the like.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a road surface roughness measuring device according to the present invention.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a block diagram of a road surface roughness measuring device according to the present invention.

FIG. 4 is a diagram showing an example of roughness measured in the present invention.

FIG. 5 is a diagram for explaining division of a measurement circle.

FIG. 6 is a flowchart for calculating an MPD in each traveling direction.

[Explanation of symbols]

 31, leg 32, frame 33, column 34, support plate 36, first leg 37, first substrate 38, reducer 39, motor 40,. · Output shaft 41 ··· First gear 41a ··· Second gear 42 ··· Second pillar 43 ··· Second substrate 44 ··· Rotary encoder 45 ··· Rotating shaft 46 ··· Bracket 47 48: Bearing 49: Bracket 50: Rotating plate 51: Laser head

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2F065 AA03 AA49 AA54 BB26 CC40 DD03 FF66 FF67 GG06 GG12 HH02 HH12 KK01 PP03 PP22 QQ01 QQ03 QQ21 QQ23 QQ27 2F069 AA06 AA60 AA64 BB24 DD15 DD25 GG04 GG07 GG04 GG08 NN26 PP02 RR12

Claims (1)

[Claims] 1. A road surface roughness measuring device used in combination with a rotary dynamic friction coefficient measuring device, comprising: a frame having a plurality of legs for installation on a road surface; A rotary encoder is mounted on the upper end of the rotary shaft, and a rotary plate is mounted on the lower end, and a motor with a speed reducer for driving the rotary shaft via gears is provided. The laser displacement gauge is installed so that the rotary dynamic friction coefficient measuring device measures the dynamic friction coefficient along the measurement circle where the dynamic friction coefficient is measured by the rotation of the rotating plate, and the measurement circle is divided into a plurality of pieces. A road surface roughness measuring device having a function of calculating a road surface roughness for each divided section based on signals from a laser displacement meter and a rotary encoder.