JP2584823B2 - Pavement thickness measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pavement thickness measuring device for measuring a pavement thickness of a pavement road surface constructed by an asphalt finisher.

[Prior Art] When paving a road with an asphalt finisher, if the pavement thickness is thinner than a design value, the pavement strength is weakened and the durability of the road surface is reduced. Conversely, if the pavement thickness is thicker than the design value, consumption of the asphalt mixture is consumed. The amount increases, resulting in an economic loss. Therefore, when paving a road, it is necessary to check the pavement thickness as required to see if the thickness is as designed.

Conventionally, pavement thickness is confirmed by inserting a rod-shaped thickness gauge with an insertion margin adjusted to a design target value into a pavement surface on which an operator has constructed.

[Problems to be Solved by the Invention] However, in the measurement of the pavement thickness by the thickness age, at the same time as the pavement road surface that has been constructed is damaged,
There was a problem that the pavement thickness could not be checked continuously, and the checking operation itself with a thickness gauge required skill, and it was very difficult to measure the pavement thickness with high accuracy.

Therefore, as shown in, for example, JP-A-61-951030, the angle of the leveling arm provided on the asphalt finisher is detected, and the horizontal distance from the center of rotation of the leveling arm to the screed for spreading the asphalt on the road surface is detected. An apparatus for measuring the pavement thickness based on these detected values has also been proposed. However, in general, the road surface on which pavement work is performed has a gentle undulation, and when the attitude of the vehicle body changes due to the undulation of the road surface, a measurement error increases, and it is still difficult to accurately measure the pavement thickness.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a pavement thickness measuring device capable of automatically and continuously measuring a pavement thickness with high accuracy.

Means for Solving the Problems In order to achieve this object, according to the present invention, a leveling arm is attached to a traveling vehicle body so as to be swingable in a vertical plane in a traveling direction, and asphalt is provided at a rear portion of the leveling arm. A screed for laying the mixture is mounted, and in a pavement thickness measuring device for measuring a pavement thickness by the screed, first, second and first and second and second roads are installed at equal intervals in front of the screed to measure the road surface height before pavement. A third road surface sensor;
A fourth road surface sensor installed behind the screed to measure the paved road surface height; and a pavement thickness calculating means for calculating the pavement thickness based on the measurement results of the first to fourth road surface sensors. It is provided.

The pavement thickness calculating means sets the distances between the installation distances of the first to third road surface sensors installed at equal intervals before the screed as 1,
From the third road surface sensor, the fourth installed behind the screed
The installation distance to the road surface sensor is nl, the measurement output of the first road surface sensor is Sf, the measurement output of the second road surface sensor is Sc, and the third is
Assuming that the measurement output of the surface sensor is Sr and the measurement output of the fourth road surface sensor is Se, the pavement thickness T (X) at the current position is However, n is calculated as an integer of 1,2,3, ...

More specifically, assuming that the installation distance from the third intended sensor installed in front of the screed to the fourth road surface sensor installed behind the screed is 2l (when n = 2), the pavement thickness T (X) Is calculated as T (X) = Se (x) + 2Sc (X + 1) + 4Sc (X + 2l) + 2Sc (X + 3l) -Sr (X) -2Sr (X + 1) -3Sr (X + 2l) -Sf (X + 2l) -2Sf (X + 3l) it can.

[Operation] In the pavement thickness measuring device of the present invention having such a configuration, the measurement outputs Sf, of the first to third road surface sensors for measuring the surface height before pavement installed in front of the screed are provided. Sc, Sr
And the pavement thickness T (X) at the current position can be automatically and continuously measured only by the measurement output Se of the fourth road surface sensor that measures the height of the paved road surface installed behind the screed.

As a result, feedback control for automatically keeping the pavement thickness constant by driving the leveling arm or the like using the measurement result of the pavement thickness according to the present invention becomes possible, and the pavement work can be performed with high precision.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In FIG. 1, reference numerals 10, 12, and 14 denote height sensors before pavement as first, second and third road surface sensors for measuring the height of the road surface before paving at three equally spaced locations in front of the screed. Measures the height of the pavement behind the screed.
Is a height sensor after paving as a road surface sensor. As the height sensor before paving 10, 12, 14 and the height sensor 16 after paving,
For example, a laser height meter can be used. In addition to the laser height meter, an appropriate height sensor can be used regardless of a non-contact type or a contact type.

Further, reference numeral 18 denotes a traveling distance sensor for measuring a moving distance of the asphalt finisher.

Reference numeral 20 denotes a pavement thickness calculation unit, as will be clarified later, the measurement output of the pre-paved height sensor 10 installed at the forefront.
Sf, the measured output Sc of the pre-paved height sensor 12 installed next, the measured output Sr of the pre-paved height sensor 14 installed immediately before the screed, and the measured output of the post-paved height sensor 16 installed behind the screed Se, and further calculates a pavement thickness T (X) of the paved road surface determined by the installation position of the post-paving height sensor 16 based on the detection output of the traveling distance sensor 18. The pavement thickness T (X) calculated by the pavement thickness calculation unit 20 is provided to the display unit 22 and is displayed, for example, in digital numerical value, and is also provided to the pavement thickness control unit 24 so that the pavement thickness is maintained at the target value. Drive control of a leveling arm and the like provided in the asphalt finisher is performed.

FIG. 2 is an explanatory diagram showing the installation state of the pre-paved height sensors 10, 12, 14 and the post-paved height sensor 16 shown in FIG. 1 with respect to the asphalt finisher.

In FIG. 2, reference numeral 26 denotes a traveling vehicle body of an asphalt finisher, and the traveling vehicle body 26 can travel by a caterpillar 30, for example. A leveling arm 34 is attached to the traveling body 26 around a rotation shaft 32. The leveling arm 34 extends to the rear of the caterpillar 30, and has a screed 36 at the lower end of the leveling arm 34 for spreading the asphalt mixture on the road surface.

Details of the asphalt finisher having such a structure are well known in, for example, Japanese Patent Application Laid-Open No. 62-29606.

In FIG. 2, pre-paved height sensors 10, 12, and 14 as first to third road surface sensors are installed at equal intervals in front of a screed 36 with an installation interval distance l. Meanwhile, the fourth
The post-paved height sensor 14 as a road surface sensor of the traveling vehicle body 26
It is attached to the tip of a sensor arm that is taken out further rearward, and is installed at a rearward position where at least the screed 36 comes off. In this embodiment, of the pre-paving height sensors 10, 12, 14 installed at equal intervals in front of the screed 36,
The post-paved height sensor 16 is installed at a position behind the screed 36, which is located at a distance of 2 l from the pre-paved height sensor 14 located immediately before the screed 36.

In addition, the height sensors 10, 12, 14 before and after paving and the height sensors after paving
The 16 installation positions may satisfy the following two conditions.

First, the pre-paving height sensors 10, 12, and 14 are provided at equal intervals in front of the work position by the screed.

Second, the post-paved height sensor 16 is provided behind the screed 36 and at an installation distance that is an integral multiple of each installation distance 1 of the pre-paved height sensors 10, 12, 14.

Accordingly, the installation distance of the post-paving height sensor 16 is n × 1 (where n = 1, rearward from the pre-paving height sensor 14 immediately before the screed) with respect to the installation distance 1 of the pre-paving height sensors 10, 12, and 14. 2,3,
(Integer of...).

Next, the principle of measurement by the pavement thickness calculating section 20 in the embodiment of FIG. 1 will be described with reference to FIGS.

FIG. 3 shows a state in which the pre-paved height sensors 10, 12, 14 and the post-paved height sensor 16 shown in FIG. 2 are installed, and the asphalt finisher runs on a undulating road surface 38 as shown in FIG. The state in which the pavement 40 having the thickness T (X) is performed is shown.

Further, in FIG. 3, a virtual reference plane 42 serving as a reference for height measurement is set for a undulating road surface 38. Further, the position of the post-paved height sensor 16 in FIG. 2 is at the X position of the virtual reference plane 42 with respect to the undulating road surface 38, the pre-paved height sensor 14 is at (X + 2l) of the virtual reference plane 42, This shows a state in which the pre-paved height sensor 12 is at the position (X + 3l) on the virtual reference plane 42 and the pre-paved height sensor 10 is at the position (X + 4l) on the virtual reference plane 42. Body reference line
It is in the inclined state shown in 26a.

On the undulating road surface 38 as shown in FIG. 3, first, the pre-paving height sensor 12 located at the position (X + 3l) of the virtual reference surface 42 has a height Se between the road surface 38 and the vehicle body reference line 26a.
(X + 3l) is generated as a measurement output, and the post-paved height sensor 16 at the position (X) of the virtual reference plane 42 detects the vehicle body reference line 26a.
Output Se (X) according to the height up to the pavement surface of pavement 40
Is generated.

The pre-paved height sensor 10 and the sensor 14 are connected to the vehicle body reference line 26a at the position (X + 4l) of the virtual reference plane 42 in FIG.
8 produces a measurement output Sf (X + 4l) determined by the interval between
On the other hand, the height sensor 14 before pavement
The measured output Sr (X + 2l) is determined by the distance between the vehicle body reference line 26a at the position + 2l) and the road surface 38.

Further, each position X, with respect to the virtual reference plane 42 in FIG.
The height of the road surface 38 of X + 2l, X + 3l, X + 4l is H (X), H (X + 2
l), H (X + 31) and H (X + 41).

In the relationship shown in FIG.
Measurement output Sc when height sensor 12 before paving shown in the figure is positioned
(X) is Sc (X) = H (X)-[{H (X-1) -Sr (X-1)} + {H (X + 1) -Sf (X + 1)}] / 2 ... 1) However, H (X); height at X position H (X-1); road surface height at (X-1) position Sr (X-1); road surface height H at (X-1) position (X + 1); road surface height at (X + 1) position Sf (X + 1); road surface height at (X + 1) position Conversely, the height H of the road surface 38 at the point X
(X) is as follows: H (X) = − 2Sc (X−1) + 2H (X−1) −H (X−21) + Sr (X−21) + Sf (X) (2)

Next, in the state of FIG. 3, the value of the height H (X + 4l) at the point (X + 4l) is expressed by using the measurement output Se of the height sensor 16 after paving and the measurement output Sc of the height sensor 12 before paving. It looks like this:

H (X + 4l) -Sf (X + 4l) = 2 {H (X + 2l) -Sr (X + 2l)}-{T (X) + H (X) -Se (X)} (3) H (X + 4l) -Sf (X + 4l) = 2 {H (X + 3l) -Sc (X + 3l)}-{H (X + 2l) -Sr (X + 2l)} (4) Therefore, the above equations (3), (4) and (2) From equation (3), the pavement thickness T (X) at point X is given by: T (X) = Se (X) + 2Sc (X + 3l) -3Sr (X + 2l) -H (X) + 3H (X + 2l) -2H (X + 3l) 5) Here, (X + 3l) of the last term on the right side in equation (5)
T (X) = Se (X) + 2Sc (X + 3l) + 4Sc (X + 2l) −3Sr (X + 2l) −2Sr (X + 1) ) -2S (X + 3l) -H (X) + 2H (X + 1) -H (X + 2l) (6) Similarly, when the height H (X + 2l) at the (X + 2l) point of the last term on the right side of this equation (6) is obtained and substituted in the same manner as in the above equation (2), the height component with respect to the virtual reference plane 42 is finally obtained. Sensor measurement output Sc, S not including H
The following equation is obtained using only e, Sf and Sr as parameters.

T (X) = Se (X) + 2Sc (X + 1) + 4Sc (X + 2l) + 2Sc (X + 3l) -Sr (X) -2Sr (X + 1) -3Sr (X + 2l) -Sf (X + 2l) -2Sf (X + 3l) ...
(7) Here, in the above embodiment, the positions X to (X + 4l) on the virtual reference plane 42 shown in FIG. 3 are represented as a function. The pavement thickness T (t) at the current time t is as follows: T (t) = Se (t) + 2Sc (t) + 4Sc (t−t1) + 2Sc (t−t2) −3Sr (t) −2Sr (t−t1) −Sr (t−t2) −2Sf (t−t1) −Sf (t−t2) (8) where, t; time at the current time position t−t1; time at which the current position is 1 before the current position t−t2; time at which the current position is 2l before the current position.

The equations (7) and (8) respectively denote the installation distance of the pre-paved height sensors 10, 12, and 14 with respect to the rear wheel 30, and the installation distance of the post-paved height sensor 16 as shown in FIG. Is set as 2l, the installation distance of which is twice as much as the example. However, the height sensor after pavement is different from the installation distance 1 of the height sensors 10, 12, 14 before pavement.
The general formula when the installation distance of 16 is generalized as an integer n times (where n is an integer of 1, 2, 3,...) Can be represented as On the other hand, with respect to the expression expressed by the time function of the expression (8), However, it can be expressed as t−t _{n + 1−i} ; the time at which the position is (n + 1−i) · l before the current position.

 Next, the operation of the embodiment shown in FIG. 1 will be described.

Now, it is assumed that the pavement thickness calculation unit 20 has been set to the calculation function according to the equation (7). When pavement work with the asphalt finisher is started in this state, the pavement thickness calculation unit
20 is a measured value Sc, S of each sensor per unit traveling distance based on the detection output of the unit traveling distance obtained from the traveling distance sensor 18.
e, Sf, and Sr are sequentially stored and held with unit distance information as an instruction parameter. The pavement thickness calculating section 20 has a pavement thickness T at the current point X where the post-paving height sensor 16 is located at a predetermined calculation cycle.
(X) is calculated based on the above equation (7).

Specifically, the measurement output Se (X), Sc at the current point X
(X + 3l) and Sr (X + 2l), measurement output Sc (X + 2l), Sr (X + l), Sf when the current point X is 1 in front of you
(X + 3l), and further, the measurement outputs Sc (X + 1), Sr (X) and Sf (X + 2l) at the time of being 2l before the current point X are read, and the calculation of the formula (7) is performed.

Similarly, every time a unit distance pulse is obtained from the traveling distance sensor 18, each measurement output is stored and held, and the calculation of the equation (7) based on the stored and held measurement output is repeated, thereby continuously obtaining the current position. Can be determined, the value of T (X) output to the display unit 22 is displayed in real time, and the measured pavement thickness T (X) is output to the pavement thickness control unit 24. Then, drive control of the leveling arm 34 is performed so as to keep the pavement thickness at a constant thickness.

Of course, the calculation by the pavement calculation unit 20 in FIG. 1 can be performed in the same manner by setting the calculation function of the expression (8) in addition to the expression (7).

In the above embodiment, as shown in FIG. 2, a track running asphalt finisher is used as an example, but a wheel running system as disclosed in JP-A-61-294005 is also used. , Can be applied as is.

[Effects of the Invention] As described above, according to the present invention, the road surface height before paving at three places by four road surface sensors installed before and after with a predetermined positional relationship with the work position by the screed is 1 Based on the detection output of the road surface height after paving at a plurality of places, the pavement thickness can be continuously measured with high accuracy without being affected by the swell even if the swell is present on the road surface.

Furthermore, in the pavement sensor of the present invention, it is not necessary to set a virtual reference plane serving as a reference for height measurement, and the pavement thickness can be measured only by the output of the height measurement by the road surface sensor. Accumulation errors expected when a virtual reference plane serving as a measurement reference is set do not occur, and the road surface thickness can be measured with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention; FIG. 2 is an explanatory diagram showing a sensor installation state of an asphalt finisher; FIG. 3 is an explanatory diagram showing a measurement principle of the present invention. 10, 12, 14: Height sensor before pavement (first to third road surface sensors) 16: Height sensor after pavement (fourth road surface sensor) 18: Travel distance sensor 20: Pavement thickness calculation unit 22: Display unit 24: Pavement thickness control unit

Claims (2)

(57) [Claims] A leveling arm is mounted on a traveling vehicle body so as to be vertically swingable in a vertical plane in a traveling direction, and a screed for laying an asphalt mixture on a road surface is mounted at a rear portion of the leveling arm. In a pavement thickness measuring device for measuring pressure, first, second and third road surface sensors installed at equal intervals in front of the screed to measure the height of a road surface before pavement; A fourth road surface sensor that is installed in the vehicle and measures a paved road surface height; and a pavement thickness calculating unit that calculates a pavement thickness based on a measurement result of the first to fourth road surface sensors; The pavement thickness calculating means sets an installation interval of the first to third road surface sensors installed at equal intervals in front of the screed, and installs the rear surface of the screed from the third road surface sensor. The installation distance to the fourth road surface sensor is nl, the measurement output of the first road surface sensor is Sf, and the measurement output of the second road surface sensor is nl.
Sc, the measured output of the third road surface sensor is Sr, and the measured output of the fourth road surface sensor is Se, the pavement thickness T at the current position.
(X) However, the pavement thickness measuring device is characterized in that n is calculated as an integer of 1, 2, 3,... 2. The pavement thickness calculating means, when an installation distance between a third road surface sensor and a fourth road surface sensor installed in front of and behind the screed is 2 l, a pavement thickness T at a current position.
(X) is calculated as follows: T (X) = Se (x) + 2Sc (X + 1) + 4Sc (X + 21) + 2Sc (X + 31) -Sr (X) -2Sr (X + 1) -3Sr (X + 21) -Sf (X + 21) -2Sf (X + 31) However, Se (x) is the measurement output of the paved road surface at the current position; Sc (X + 1) is the measurement output of the unpaved road one point ahead of the current position (X); Sc (X + 2l) is 2l from the current position (X) 2. The pavement thickness measuring apparatus according to claim 1, wherein the measurement output of the previous unpaved road surface; Sc (X + 3l) is calculated as the measurement output of the unpaved road surface 3l ahead of the current position (X).