JPH0749642B2 - Pavement thickness control method for leveling machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a pavement thickness control method used for a leveling machine such as an asphalt finisher or a base paver.

[Conventional technology]

One of the methods for paving the subbase is a method of paving while ensuring a desired flatness so that the finished surface does not undulate. This is a paving method based on so-called flatness.

Conventionally, when implementing a paving method based on flatness, if there is a structure such as a curb beside the road or construction site to be paved, that structure is used as a reference, and the structure that becomes the reference If there is no such mark, the operator operates the machine by directly looking at the finished surface.

[Problems to be Solved by the Invention]

However, among the above-mentioned pavement methods, the former pavement method that uses a structure as a reference can relatively easily make a pavement that maintains a flatness that is even with the shape of the structure. Is not always convenient.

Further, when the screed operator visually judges the paved surface to determine the flatness, the visual illusion cannot be eliminated merely by relying on the intuition, and the accuracy is poor.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a leveling machine capable of accurately finishing a pavement surface flat without relying on an external standard or an operator's intuition. It is to provide a pavement thickness control method.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides a laying machine for controlling the thickness of pavement laid by the screed by changing the position of the screed provided in the rear portion of the vehicle so as to be tiltable in the front-rear direction. In the pavement thickness control method in, the height of the existing pavement surface is measured every predetermined distance in the traveling direction, and the flatness reference straight line is created from the height differences of the plurality of measurement points, while the flatness reference straight line is created. Of the plurality of measurement points used, a flatness prediction straight line is created from the height difference of a plurality of measurement points located on the front side in the traveling direction, which is less than that, and at the target point ahead of the screed in the traveling direction by a predetermined distance, The screed is controlled so as to eliminate the difference between the position on the flatness reference straight line and the position on the flatness prediction straight line.

[Action]

The above flatness reference straight line represents an ideal finished surface indexed from the existing pavement surface in order to ensure flatness, while the flatness prediction straight line shows the road surface when the screed is kept in that state. Indicates that the flatness is finished along the straight line.

By comparing the two and controlling so that they do not differ at a target point that is a predetermined distance ahead of the place where the screed is being paved, specifically, the desired flatness is ensured at a predetermined distance ahead. It means paving while controlling the screed in advance.

The pavement thickness does not change immediately after changing the inclination of the screed, and the result appears when the vehicle runs a predetermined distance. Therefore, as described above, screed control is performed so that desired flatness can be obtained at a target point ahead by a predetermined distance.

〔Example〕

The attached drawings show an embodiment of the present invention applied to an asphalt finisher. Reference numeral 1 in FIG. 1 is a traveling vehicle of an asphalt finisher AF. At its front part, a hopper 2 is provided for putting the asphalt mixture. The asphalt mixture in the hopper 2 is transferred rearward (to the right in FIG. 1) by a feeder at the bottom of the vehicle body, then spread evenly left and right by a screw, and spread by a pair of left and right screeds 3.

The screed 3 is mounted on the traveling vehicle 1 via the leveling arm 4.
It is supported by a support shaft 5 provided on a substantially central side surface of the. The support shaft 5 is vertically moved by a pivot cylinder 6. The basic structure of the asphalt finisher AF is well known.

At the rear part of the screed frame 3a supporting the screed 3, road surface shape measuring devices A and A (only the left measuring device is shown in FIG. 1) are provided on the left and right. The road surface shape measuring device A on the left side is fixed to the screed frame 3a via a bracket, and the road surface shape measuring device A on the right side is horizontally rotatably attached to the screed frame 3a via a hinge and then via the bracket. It is fixed. The two measuring devices A, A are manufactured symmetrically, and their measuring functions are exactly the same. Therefore, the left measuring device A will be described in detail below.

The road surface shape measuring device A mainly includes a reference member 8, a pair of first and second distance sensors 9 and 10, and an inclination sensor 11.

As shown in FIG. 3, the reference member 8 is made of an angle member, and is fixed to the bracket 7 with bolts 13 with its length direction aligned with the traveling direction of the traveling vehicle. Also the fourth
As shown in the figure, fixed frames 14 having a U-shaped cross section are provided at both ends of the reference member 8 by fixing both end edges and upper edges thereof to the reference member 8 by means such as welding. Then, inside each fixed frame 14, the mounting plate 15 is made of a vibration-proof material such as rubber.
It is attached with a bolt 17 and a nut 18 via 16, respectively. Further, as shown in FIG. 5, a fixing plate 20 is provided at the central portion of the reference member 8 by welding the side edge and the upper edge thereof.
It is fixedly attached to. A mounting plate 22 having a support 21 is attached to the fixed plate 20 with a bolt 24 and a nut 25 via a vibration damping material 23 such as rubber.

The first and second height sensors 9 and 10 are mounted on the mounting plate 15 by bolts 26.
Can be installed with. A first height sensor 9 provided close to the screed frame 3a and a second height sensor 10 provided rearward from the screed frame 3a are provided on a road surface facing the reference member 8 vertically. P ₁ , P ₂ (6th
Measure the distances H ₁ and H ₂ respectively (see the figure). There are various types of the first and second height sensors 9 and 10, such as laser type and ultrasonic type, but the type and structure are arbitrary. A backing plate 27 is attached to the fixed frame 14 with a screw 28 by closing the through hole 14a of the fixed frame 14. The height sensors 9 and 10 output their measurement signals to the arithmetic unit 30.

Further, the tilt sensor 11 is attached to the support base 21 with bolts 29a and nuts 29b. The inclination sensor 11 measures the inclination of the reference member 8 within the vertical plane in the longitudinal direction. The tilt sensor 11 also outputs the measurement signal to the arithmetic unit 30.

Further, reference numeral 19 in FIG. 1 denotes a distance sensor for traveling distance calculation provided at the lower end of the front part of the traveling vehicle 1.
Also outputs the measurement signal to the arithmetic unit 30.

The arithmetic unit 30 receives an analog output of the height sensors 9 and 10 and the tilt sensor 11 and converts the analog output into a digital output.
(Analog-digital) converter 31 and this A / D converter 31
And I / O to which each digital output of the distance sensor 19 is input
(Input-output) Interface 32 and operation unit that performs operations based on data from this I / O interface 32
33 and the numerical value obtained by this calculation unit 33 is input and stored,
Also, a data storage unit 34 for outputting to the arithmetic unit and an I / O interface 35 for processing the numerical values calculated by the arithmetic unit 33.
It consists of and. And I / O interface 3
The signal output from 5 is sent to a solenoid valve 36 for adjusting the expansion and contraction of the pivot cylinder 8.

Then, the arithmetic unit 30 receives a signal output from the distance sensor 19 every time the reference member 8 moves the distance m between the two distance sensors 9 and 10 together with the traveling vehicle, and performs a required calculation.

The main calculation contents of the calculation device 30 are a pair of height sensors 9 and 10.
Two measurement points P ₁ , P ₂ , P ₂ ,
By calculating the height differences δ ₁ , δ _2, ... Of P ₃ , P ₃ , P _4, ..., From the height differences δ ₁ , δ _2, ...
The flatness reference straight line l ₁ (y _n = ax _n + b) is calculated by introducing a multiplication method, and the number of measurement points used to calculate the flatness reference straight line is smaller than that and the vehicle 1 travels. Multiple measurement points located on the front side in the direction (eg P ₁ ,
Height difference [delta] _n-1 of the P _2), flatness expected from [delta] _n the straight line l ₂ (y _f = a _f
x + b _f ) so that the difference ε between the position on the flatness reference straight line l ₁ and the position on the flatness expected straight line l ₂ at the target point ahead of the screed 3 in the traveling direction by a predetermined distance (m) is eliminated. , The operation amount L of the pivot cylinder 6 to change the position of the screed 5.

At this time, the pavement thickness influences not only the inclination of the screed 3, but also the properties and supply amount of the asphalt mixture, the traveling speed of the vehicle 1 and the like, and these are also taken into consideration.

Then, the pivot cylinder 6 calculated by the calculating unit 33
The command signal for the operation amount L is sent to a solenoid valve 36 provided in a hydraulic circuit (not shown), and the pivot cylinder 6 is expanded and contracted by operating the solenoid valve 36.

Here, the height difference δ _new between the measurement points P ₁ and P ₂ simultaneously measured by the pair of height sensors 9 and 10 is calculated based on the following equation (see FIG. 6).

δ _new = H ₁ cos θ + msin θ−H ₂ cos θ (1) H ₁ : value detected by the first height sensor H ₂ : value detected by the second height sensor m: second and first The distance between the height sensors θ: The inclination of the reference member 8 The flatness reference straight line l ₁ is based on the height difference δ calculated above, for example, the latest four points (P ₁ , P ₂ , P ₃ , P _{From 4} ), it is calculated by the method of linear approximation by the least squares method (see Fig. 7).

Further, the flatness reference straight line l ₂ is calculated, for example, by connecting the latest two points (P ₃ , P ₄ ) on the basis of the calculated height difference δ (see FIG. 8).

Next, a pavement thickness control method by the leveling machine configured as described above will be described.

Asphalt finisher AF is used for paving roads in the same way as before, while the traveling vehicle 1 is traveling at a constant speed. Spread the mix with screed 3 and level it.

In the above, the traveling distance of the vehicle 1 is measured by the distance sensor 19, and the first and second traveling distances are calculated every time the traveling distance becomes m.
The height sensors (9, 10) measure the height (distance) from the roadbed surface and output the measurement result to the arithmetic unit (30).

The arithmetic unit 30 calculates the height difference Δ from the output signals of the height sensors 9 and 10, the distance sensor 19 and the tilt sensor 11 as described above. Then, based on these values, the flatness reference straight line l ₁ : y _n = ax _n + from the latest 4 points (P ₁ , P ₂ , P ₃ , P ₄ ) on the paved surface
Calculate b. Also, based on the height difference δ, the flatness prediction straight line l ₂ : y _f = a _f x + b is calculated from the latest two points (P ₃ , P ₄ ).

Then, the operation amount of the pivot cylinder 6 is determined so as to eliminate the difference ε between the value on the flatness reference straight line and the value on the flatness prediction straight line at the target point ahead of the predetermined distance m in the traveling direction of the screed 3. To do.

The calculated value is transferred to the solenoid valve 36 via the I / O interface 35.
And the pivot cylinder 6 is expanded and contracted to control the screed 3.

The above operation is repeated every time the vehicle 1 travels the distance m, so that the screed 3 is controlled so that the pavement in front of the distance m always maintains flatness.

Examples and technical matters other than the above will be listed below.

(1) In the above embodiment, the distance between the height sensors 9 and 10 is set to m, but the present invention is not limited to this, and m / 2,
It may be set to m / 3 or 2m. However, setting m or m / 2 as in the embodiment has an advantage that the measuring apparatus A can be downsized.

(2) The height sensors 9 and 10 are not limited to ultrasonic sensors, but laser type or expandable cylinders may be used, and their specific structures are arbitrary.

(3) In the above embodiment, the flatness reference straight line l ₁ is calculated by the least-squares method using the latest four points P ₁ , P ₂ , P ₃ , P ₄ after paving. Without being limited to this,
It may be calculated based on the latest 5 points or more. Further, in the above embodiment, the flatness prediction straight line l ₂ is calculated by connecting the latest 2 points after pavement and connecting them, but the present invention is not limited to this, and the latest 3 points are used to obtain a minimum 2 The calculation may be performed by introducing a multiplication method, and the point is that the number of measurement points is smaller than the measurement point used for calculating the flatness reference straight line and the measurement point on the front side thereof is selected and calculated.

〔The invention's effect〕

As described above, according to the pavement thickness control method for a leveling machine according to the present invention, an expected straight line of the finished surface in front of the screed can be obtained without using a special measuring device, and it is within a predetermined range. Since the pavement flatness is controlled so that it can be settled, it is possible to pave the finished surface without relying on the intuition of an operator or the like.

[Brief description of drawings]

FIG. 1 is a side view of an asphalt finisher for carrying out the method of the present invention, FIG. 2 is a block diagram of a computing device, and FIG.
FIG. 4 is an enlarged view of a circle portion III in FIG. 4, FIG. 4 is a view showing a mounting state of a height sensor, FIG. 5 is a view showing a mounting state of an inclination sensor, and FIG. 6 is an explanatory diagram for obtaining a road surface height difference, FIG. 7 is an explanatory diagram for obtaining a flatness reference straight line, FIG. 7 is an explanatory diagram for obtaining a flatness reference straight line, and FIG. 8 is a diagram shown for explaining the method of the present invention. 1 ... Vehicle, 5 ... Screed, 8 ... Pivot cylinder, A ... Measuring device, 9 ... First height sensor, 10 ...
Second height sensor is, 11 ...... tilt sensor 19 ...... distance sensor, 30 ...... controller, l ₁ ...... flatness reference line, l ₂ ...... flatness expected linear.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaaki Saito 27 Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Inside the Niigata Iron Works Development Center Co., Ltd. Address Niigata Construction Machinery Co., Ltd. (56) References: Actual Development Sho 63-272803 (JP, U) Actual Public Sho 62-33763 (JP, Y2)

Claims (1)

[Claims] 1. A pavement thickness control method for a leveling machine for controlling the thickness of pavement spread by the screed by changing the inclination of a screed provided in the rear part of a vehicle so as to be tiltable in the front-rear direction. The height of the paved surface is measured at predetermined distances in the traveling direction, and a flatness reference straight line is created from the height difference between the plurality of measurement points, while the flatness reference straight line of the plurality of measurement points used to create the flatness reference straight line. A flatness prediction straight line is created from the height difference between a plurality of measurement points located in the front in the traveling direction, which is less than that, and at the target point ahead of the predetermined distance in the traveling direction of the screed, on the flatness reference line. A pavement thickness control method in a leveling machine, characterized in that the screed is controlled so as to eliminate the difference between the position and the position on the flatness prediction straight line.