System for measuring irregularities of road surface

A system for measuring irregularities of a road surface, wherein laser rays irradiated on the road surface are received and processed in a predetermined manner. This system includes a body frame mounted on the road surface, a movable frame movably supported by this body frame, and a laser ray transmitting-receiving section connected to this movable frame. The laser ray transmitting-receiving section is additionally provided thereon with a signal process circuit, by which received signals are processed in a predetermined manner, whereby the irregularities of the road surface are measured. Processing performed in the signal process circuit is controlled in timing in accordance with a moving speed of the laser ray transmitting-receiving section.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a system for measuring irregularities of a road 
surface, and more particularly to a system for measuring irregularities of 
a road surface using laser rays. 
2. Description of the Prior Art 
FIG. 6 shows a conventional example which includes a body frame 1 that is 
stoppingly; provided on a road surface E during measuring, a slide frame 2 
that is reciprocatorily movable to the left or right (in the drawing) 
along the body frame 1, roller-type measuring means 3 that is mounted on 
the slide frame 2, and an encoder 4 for sensing a vertically moving value 
(i.e., a change in h) of the roller-type measuring means 3 for directly 
measuring the irregularities of the road surface by moving the roller-type 
measuring means 3 in a direction A or B in the drawing. 
The conventional example described above is of such an arrangement that, 
since rollers 3A constituting a sensor section of the roller-type 
measuring means 3 are brought into contact with the road surface and 
rotatably movable, it is impossible to perform measuring at high speed, 
and, in switching from one direction over to another, such problems have 
been presented that, the roller-type measuring means 3 should be operated, 
the body frame as a whole should be rearranged to the opposite direction 
and so on, whereby much labor is taken, abrupt changes in irregularities 
cannot be followed up in many cases, and further, the measuring accuracy 
is so limited that the measuring accuracy is directly affected by the 
diameter of the rollers. 
SUMMARY OF THE INVENTION 
The present invention has been developed to obviate the above-described 
disadvantages of the prior art and has as its object the provision of a 
system for measuring irregularities of a road surface it is wherein, 
possible to take measurements at high speed and wherein, general 
irregularities can be reliably detected with high accuracy. 
To achieve the above-described object, the present invention contemplates 
an arrangement that includes: a laser ray transmitting-receiving section 
that is opposed to the road surface; a body frame for holding the laser 
ray transmitting-receiving section at a predetermined height above the 
road surface; and a carrier means mounted on the body frame for moving the 
laser ray transmitting-receiving section along the body frame from one end 
to the other, the laser ray transmitting-receiving section being 
additionally provided thereon with an exciting circuit section for 
energizing the continuous operation of a predetermined laser outputting 
section and a signal process circuit section for receiving reflected and 
diffused rays from the road surface and detecting predetermined 
irregularities information; whereby the number of times of signal 
processing per unit time of received signals in the signal process circuit 
is changed in synchronism with a moving speed of the laser ray 
transmitting-receiving section on the body frame.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
One embodiment of the present invention will hereunder be described with 
reference to FIGS. 1 to 3. 
FIG. 1, shows a road surface which is designated as E, a laser ray 
transmitting-receiving section 11 and a body frame 12 which extends from 
left to right. 
In this embodiment, the laser ray transmitting-receiving section 11 is 
divided into a laser ray transmitting portion 11A, comprising a laser 
diode and the like, and a laser ray receiving portion 11B, comprising by a 
one-dimensional CCD sensor and the like. As shown in FIG. 1, the laser ray 
transmitting-receiving section 11 is opposed to the road surface E and is 
mounted to the body frame 12 by a slide frame 14, comprising part of a 
carrier means 13. 
Similarly to the body frame 12, the carrier means 13 includes the slide 
frame 14, which extends from left to right, as shown in FIG. 1, a carrier 
chain mechanism 15 mounted on the slide frame 14, and driving means 16 for 
driving the carrier chain mechanism 15. 
The slide frame 14 engages the body frame 12 through a first guide means 17 
and is supported thereby. The first guide means 17 is provided along the 
body frame 12. Thus, the slide frame 14 is constructed as to be 
reciprocatorily movable along the body frame 12 in a direction A or B, as 
shown in FIG. 1. 
The slide frame 14 is mounted to the body frame 12 with the laser ray 
transmitting-receiving section 11 attached to a second guide means 18. The 
second guide means 18 is provided along the slide frame 14. Thus, the 
laser ray transmitting-receiving section 11 is constructed so as to be 
reciprocatorily movable along the slide frame 14 in a direction C or D. As 
described above, the laser ray transmitting-receiving section 11 is 
supported by the slide frame 14 and is engaged with the carrier chain 
mechanism 15. As will be described hereunder, the laser ray 
transmitting-receiving section 11, being biased by the carrier chain 
mechanism 15, moves on the slide frame 14. 
The driving means 16 for driving the carrier chain mechanism 15 on the 
slide frame 14 comprises a driving motor 20 that is mounted on the body 
frame 12 and a driving chain mechanism 21 for imparting a turning force of 
the driving motor 20 to the carrier chain mechanism 15, as shown in FIG. 
1. The driving chain mechanism 21 is mounted on the body frame 12 and 
extends downward in the drawing. For this, the driving chain mechanism 21 
and the driving motor 20 are always operable at predetermined positions. 
The laser ray transmitting section 11A of the laser ray 
transmitting-receiving section 11 is additionally provided with an 
exciting circuit section 30 for continuously outputting laser rays of a 
predetermined level similarly, the laser ray receiving section 11B is 
provided with a signal process circuit section 31 for detecting the 
information of irregularities of the road surface E from the received 
laser rays and processing the same. 
As shown in FIG. 2, the signal process circuit section 31 includes a pulse 
signal oscillator 32 and a frequency divider 33. 
The pulse signal oscillator 32 has a construction whereby the number of 
repeated times of timing signals, which are signals outputted therefrom, 
is regulated by an encoder (that is energized by the driving motor 20) to 
be described hereunder. Furthermore, in this embodiment, the frequency 
divider 33 comprises a plurality of frequency dividers 33A, 33B and 33C 
which are switchingly usable, as necessary. 
The signal process circuit section 31 further includes a receiving circuit 
35, a signal process circuit 36 and a memory 37. The signal process 
circuit 36 functions in such a manner that it receives an input from the 
frequency divider 33, so that it operates in synchronism with the signal 
from the frequency divider 33, detects predetermined distance information 
and information of irregularities, and stores the same in a memory 37. 
Braking means 40 is fixedly mounted on the body frame 12, and normally 
functions to slowly apply a braking force to the slide frame 14. In 
measuring the irregularities of an inclined surface for example, the 
braking means 40 serves to prevent the slide frame 14 from freely sliding 
downward. Sensors 41A and 41B constantly detect the presence of the slide 
frame 14. When the braking means 40 is energized by the outputs from the 
sensors 41A and 41B, the slide frame 14 is stopped from moving. Legs 42 
and 43 are mounted on the body frame 12. Furthermore, stoppers 44 and 45 
for engagingly stopping the laser ray transmitting-receiving section 11 
from moving are, provided. 
The above-described carrier chain mechanism 15, driving means 16 and the 
like are described further in detail with reference to FIGS. 1 and 3. 
As shown in FIG. 1, the carrier chain mechanism 15 comprises by chain 
wheels 15A and 15B, which are mounted on the slide frame 14, and a carrier 
chain 15C which is stretched across the chain wheels 15A and 15B. As shown 
in FIG. 3, in this embodiment, the slide frame 14 is formed into a box 
shape which is downwardly open, and the chain wheels 15A and 15B are 
rotatably mounted at opposite end portions in the slide frame 14, as shown 
in FIG. 1. 
Mounted on opposite side surfaces of the slide frame 14 (shown in FIG. 3) 
are the aforesaid first and second guide means 17 and 18, respectively. 
The first and second guide means 17 and 18, as actually shown in FIG. 3, 
comprise guide rails 17B and 18B which are parallelly fixed to opposite 
side surfaces of the slide frame 14 at regular intervals therefrom and a 
set of four engaging rollers 17A, 17A, 18A, 18A, which are engaged with 
the top and bottom ends of the guide rails 17B and 18B. While only two 
sets of rollers are disclosed in FIG. 3, additional rollers can be 
included. In the present embodiment, the set of four engaging rollers 17A, 
17A, . . . on one hand, are mounted at four positions S1, S2, S3 and S4 on 
the body frame 14, as shown in FIG. 1, so that the rollers 17A, 17A, . . . 
can engage and guide the slide frame 14 at two or more positions during 
the moving of the slide frame 14. Furthermore, the set of four engaging 
rollers 18A, 18A, . . . on the other hand are rotatably mounted to a case 
portion 11C of the laser ray transmitting-receiving section 11, as shown 
in FIG. 3. 
The driving means 16 comprises the motor 20 mounted thereon with a 
reduction gear mechanism 50, the driving chain mechanism 21 engaging with 
an output shaft on the driving chain mechanism 21 and a driving chain 
wheel 52 connected to the driving chain mechanism 21. The driving chain 
mechanism 21 comprises two chain wheels 21A and 21B, and a driving chain 
21C stretched across the chain wheels 21A and 21B. As shown in FIG. 3, the 
chain wheel 21B is coaxially mounted thereon with the driving chain wheel 
52, which is driven by the carrier chain mechanism 15. As shown in FIG. 3, 
the case portion 11C of the laser ray transmitting-receiving section 11 is 
engaged through a connecting portion 11D with the carrier chain 15C of 
this carrier chain mechanism 15. 
Coupled onto an output shaft of the reduction gear mechanism 50 is an 
encoder 60 for regulating the repeat times of the pulse signals outputted 
from the pulse signal oscillator 32. Sensor portion 32 of the pulse signal 
oscillator 32, receives a predetermined signal from the encoder 60, while 
a case portion 32 stores the pulse signal oscillator 32. 
A general description of the operation of the above embodiment will 
hereunder be described. 
First, in a normal state, the braking means 40 moderately engages the slide 
frame 14, whereby the slide frame 14 is stopped in movement. When the 
driving means 16 is actuated and the carrier chain 15C is rotated for 
running to the left, as shown in FIG. 1, the laser ray 
transmitting-receiving section 11 together with the carrier chain 15C 
integrally move in the direction C. Here, even when the laser ray 
transmitting-receiving section 11 comes into abutting contact with stopper 
44 on the slide frame 14, the driving means 16 does not stop at all. When 
the laser ray transmitting-receiving section 11 comes into abutting 
contact with the stopper 44, thereupon, the slide frame 14 moves 
integrally with the laser ray transmitting-receiving section 11 to the 
right in FIG. 1 when the latter moves. 
When the left end portion of the slide frame 14, as shown in FIG. 1, moves 
to the right beyond position sensor 41B, the braking means 40, upon 
receiving the information, is immediately actuated to release the motor 20 
from the power source and stop the slide frame's 14 movement. 
Subsequently, a control means, not shown, is operated to reverse the 
rotation of the motor 20 (by this operation, the braking means 40 is 
simultaneously released from a completely stopped operation of the slide 
frame 14). In this case, the laser ray transmitting-receiving section 11 
positioned at the right end portion, as shown in FIG. 1, moves being to 
the left in the direction D. 
On the other hand, the slide frame 14 does not move due to the moderate 
engaging action by the braking means 40. The laser ray 
transmitting-receiving section 11 moves in the direction D until it comes 
into abutting contact with the stopper 45 mounted at the left end portion 
of the slide frame 14, as shown in FIG. 1. The laser ray 
transmitting-receiving section 11, which has come into abutting contact 
with the stopper 45, moves together with the slide frame 14 to the left in 
the drawing. Then, when the right end portion of the slide frame 14 in 
FIG. 1 moves to the left beyond the position sensor 41A, the braking means 
40, upon receiving the information, immediately releases the motor 20 from 
the power source and stops movement of the slide frame 14. 
Hereinafter, operations similar to the above are performed, whereby, in the 
laser ray transmitting-receiving section 11, the operations similar to the 
above are repeatedly performed, during which irregularities of the road 
surface can be effectively measured. 
In this embodiment, it is possible to measure the irregularities of the 
road surface as large as a distance covering the movement of the slide 
frame 14 on the body frame 12 (in this embodiment, this distance is 
substantially equal to the distance of a protrusion of the slide frame 14 
from the body frame 12) in addition to a moving distance L of the laser 
ray transmitting-receiving section 11 on the slide frame 14. 
When the moving speed of the laser ray transmitting-receiving section 11 is 
constant, the pulse signal oscillator 32 outputs pulse signals by 
repeating cycles predetermined by the encoder 60 and the frequency divider 
33. The signal process circuit 36 is actuated in association with the 
repeating cycles of the pulse signals, to thereby process input signals 
and deliver the same into the memory 37. The repeating cycles of the 
measured data written into the memory 37 are constant. On the other hand, 
when the RPM of the driving motor 20 is raised to increase the moving 
speed of the laser ray transmitting-receiving section 11, the RPM of the 
encoder 60 is increased in proportion thereto, whereby the value of 
information written into the memory 37 is increased as well. For this, it 
is so advantageous that, even if the irregularities of the road surface 
are measured at high speed, pitches of distance on the road surface is 
completely equal to those in the case where the measuring is performed at 
low speed, so that it becomes possible to perform the measuring at high 
speed without changing the measuring accuracy. Furthermore, the frequency 
divider can be suitably switched to change the interval between the 
measuring times, and this respect is preferable when irregularities of a 
bottom face is measured in excavating over a large area in case of 
construction works and the like. 
FIG. 4 shows another example of the signal process system. In this example, 
an output from a transmitting circuit 34 is delivered to the laser ray 
transmitting portion 11A, where pulse-like laser rays are outputted. The 
output from the transmitting circuit 34 is simultaneously delivered to a 
time difference detecting circuit 36A on the side of the receiving 
circuit, whereby a time difference between the pulse-like laser ray and 
received signal delivered from the receiving circuit 35A is detected. 
Thereafter, the time difference is changed converted to a distance by a 
distance change circuit 36B and stored in the memory 37. 
Other aspects of the arrangement are similar to those in FIG. 2. 
This example can offer advantages in that, even with this arrangement, 
substantially the same results as in FIG. 2 are obtainable, and the idea 
based on the time difference leads to the detection of irregularities of 
the road surface without being affected by increases or decreases of the 
sensitivity. 
In the above embodiment, there is exemplified a case where the laser ray 
transmitting portion 11A and the laser ray receiving portion 11B of the 
laser ray transmitting-receiving section 11 are arranged in a plane that 
is parallel to the moving direction of the laser ray 
transmitting-receiving section 11. However, the portions 11A and 11B may 
be arranged in a plane that perpendicularly intersects the moving 
direction of the laser transmitting-receiving section 11. 
In the above embodiment, there is particularly exemplified a case where the 
body frame 12 is mounted on the road surface E through legs 42 and 43. 
However, the present invention need not necessarily be limited to this, 
and the legs 42 and 43, as shown in FIG. 1, can be removed and the body 
frame 12 be mounted on a motor vehicle, as shown in FIG. 5. The above 
arrangement can offer the advantage of quickly coping with the movement of 
the measuring position. 
The present invention can be applied to measuring the irregularities of a 
surface of the earth other than the road surface as it is. 
The present invention, being arranged and functioning as described above, 
can provide an outstanding system for measuring irregularities of a road 
surface, which has not been seen in the past, wherein it becomes possible 
to measure information of irregularities of the road surface and changes 
thereof with high accuracy and at high speed by its arrangement of 
continuously measuring the road surface by the use of laser rays. 
Accordingly, the measuring work can be facilitated, and, adverse 
influences due to temperature and humidity in a measuring region can be 
eliminated.