JPH0749646B2 - 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.

[Prior Art] When paving a road or the like, it is usually required to finish the surface flat.

Conventionally, one of the methods for finishing the paved surface is to use curbs or gutters existing on the side of the road to be paved as reference planes (lines) and finish the paved surface according to those reference planes. was there.

Further, a long ski having a length substantially equal to the length of the vehicle is arranged along the traveling direction on the side of the vehicle, and the unpaved surface is regarded as a flat surface with little unevenness in advance by the long ski, There is also a method of finishing the paved surface along the flat surface.

[Problems to be Solved by the Invention]

However, the former method of paving while using a curb or the like as a reference surface does not always have a curb or the like, and even when there is a curb or the like, there is a drawback that the flatness of the ground is gradually deteriorated as the distance from the curb increases. there were.

Further, the latter type has a drawback that it requires a large ski because it requires long skiing, and accordingly has a drawback that it is difficult to implement it on a narrow road.

Further, the control using long skis is to control the shape of the roadbed by flattening it to some extent so as to reduce unevenness, and not to control the pavement thickness itself.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a pavement thickness control method in a paving machine capable of controlling the pavement thickness itself without using a large-scale device such as a long ski. To do.

[Means for Solving the Problems]

In order to achieve the above object, in the invention according to claim 1, a pair of height sensors are arranged on the laying machine at a predetermined interval in the traveling direction, and the inclination angles of the pair of height sensors are arranged. And a pair of height sensors each time the leveling machine travels a separation distance of the pair of height sensors based on an output signal from a distance sensor provided in the leveling machine, The height of the unpaved surface is measured by the inclination sensor, the least squares method is introduced from those values to create a reference flat line, and the reference flat of the unpaved surface at a target point ahead of the screed by a predetermined distance in the traveling direction. A feature is that the amount of deviation from the line is obtained and the screed is controlled according to the amount of deviation.

According to a second aspect of the present invention, in addition to the constituent elements of the first aspect of the invention, the pair of height sensors are arranged in connection with a screed, and the measured value of the unpaved surface is measured by the height sensor. The pavement thickness of the existing pavement surface is calculated from the above, the average value of the calculated pavement thickness is compared with a predetermined target pavement thickness, and the result is fed back to the screed while periodically correcting the deviation amount. It is characterized by controlling.

[Action]

In the invention described in claim 1, the reference flat line calculated from the measurement of the pair of height sensors is a substitute for the long ski described in the related art. That is, in this method, a surface (line) that serves as a reference during pavement in calculation is obtained based on the measurement values of the pair of height sensors without using a special device such as a long ski.

Then, the vertical deviation amount from the reference surface to the unpaved surface is calculated, and the inclination of the screed is controlled so as to eliminate the deviation amount. Therefore, it is as if the reference surface were moved in parallel upward. A fine finished surface can be obtained.

In the invention according to claim 2, the pavement thickness of the existing pavement surface is calculated from the height difference between the two points measured by the pair of height sensors, and when the pavement thickness deviates greatly from the target pavement thickness,
In the following control, the pavement thickness approaches the target pavement thickness,
A correction is added to the constant used in the calculation formula for determining the slope of the screed. Thereby, the flatness of the pavement surface can be ensured, and the pavement thickness can be brought close to a desired value.

〔Example〕

The attached drawings show an embodiment of the present invention applied to an asphalt finisher. Reference numeral 1 in FIG. 1 denotes 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 5.

The screed 5 is mounted on the traveling vehicle 1 via the leveling arm 6.
It is supported by a support shaft 7 provided on the substantially central side surface of the. The support shaft 7 is vertically moved by a pivot cylinder 8. Note that the basic structure of the above-mentioned asphalt initiator AF is well known.

Further, reference numeral 11 is a measuring device provided on each of the left and right sides. The measuring device 11 measures a first height sensor 13 provided at the tip of the measuring arm 12, a second height sensor 14 provided at the center of the measuring arm, and an inclination angle of the measuring arm 12. It is composed of a tilt sensor 15. The base end (right end in the figure) of the measuring arm 12 is pin-supported by the frame 5a supporting the screed 5, whereby the measuring arm 12 tilts evenly with respect to the screed 5.

Although various types of first and second height sensors 13 and 14 can be considered, a sensor utilizing ultrasonic waves is used here. Further, as shown in FIG. 3, the distance between the two sensors 13 and 14 is set to 1/2 of the distance between the second distance sensor 14 and the rear end of the screed 5 (if it is a fraction of an integer). And the relative height H ₀ of both sensors 13, 14 to the screed 5 is
The screed 5, the measuring arm 12 and the like are set to have constant values regardless of the inclination.

Reference numeral 17 denotes a distance sensor provided at the lower end of the front part of the traveling vehicle 1 for calculating a traveling distance.

Reference numeral 18 denotes an L-shaped arm attached so as to move up and down integrally with the screed 5. A base end side (right side in FIG. 1) of the arm 18 is fixed to a screed supporting frame not shown, and a third height sensor 19 for measuring a distance from the road surface is attached to a tip of the arm 18. There is. The third sensor 19 is arranged just in the center of the rear end of the second height sensor 14 and the screed 5, so that the rear end of the screed 5, the third height sensor 19, and the third height sensor are finally arranged. Sensor 19
And the second height sensor 14, and the second height sensor and the first
The height sensors 13 are arranged at the same distance M from each other. The third sensor 19 includes the first and second
Similar to the height sensors 13 and 14 of FIG.

Height sensor 13,14,19, tilt sensor 15, and distance sensor
An arithmetic unit 30 is connected to 17 (see FIG. 2). The arithmetic unit 30 receives the analog outputs of the height sensors 13 and 14 and the tilt sensor 15 and converts them into digital outputs.
(Analog-digital) converter 31 and this A / D converter 31
And I / O to which each digital output of the distance sensor 17 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,
Further, the data storage unit 34 for outputting to the arithmetic unit 33, and the arithmetic unit
The pavement thickness check calculation unit 3 that periodically checks whether the constant α ₀ used in the calculation in 33 matches the current pavement thickness control, and if it does not match the current condition, corrects the constant α _0.
5 and data processing of the numerical value calculated by the calculation unit 33 I
It consists of an / O interface 36.

A signal output from the I / O interface 36 is sent to a solenoid valve 37 interposed in a hydraulic circuit (not shown), and the pivot cylinder 8 is operated by operating the solenoid valve 37.
Is designed to be expanded and contracted.

The arithmetic unit 30 performs a required calculation based on the measurement signal sent from the height sensors 13 and 14 every time the traveling vehicle 1 travels the distance M between the height sensors 13 and 14.

The main calculation contents of the calculation unit 33 are a pair of height sensors 13 and 14
Two measurement points P ₁ , P ₂ , P ₂ ,
The height differences δ ₁ , δ ₂ ... of P ₃ , P ₃ , P ₄ ... are calculated (see Fig. 3) and at the same time the pavement thickness t of each measurement point P ₁ , P ₂ ... is calculated, The standard square line y = ax + b is calculated by introducing the least squares method from the height difference δ, and the difference E = δ ₁ −y _B between the calculated standard mean line and the roadbed is calculated, and the operation steady state of the asphalt finisher AF is determined. The constant α ₀ used to calculate the control target value L ₁ measured by the third height sensor 19 is determined based on the data when the state is reached, and the constant α ₀ and the calculated value E are set to Based on the third
The control target value L ₁ measured by the height sensor 19 is calculated, and this value and the actual measurement value L measured by the third height sensor 19 are calculated.
The operation amount of the pivot cylinder 8 is calculated so as to control the screed 5 so as to eliminate this deviation when the slippage occurs.

When the measured value L measured by the third height sensor 19 deviates from the control target value L ₁ , the screed 5 is controlled so as to eliminate this deviation. Further, it is performed based on the data input to the data storage unit 34.

In addition, the main calculation contents in the pavement thickness check calculation unit 45 are:
An average value Ta of a plurality of predetermined points is calculated from the calculated pavement thickness t calculated above, and a difference ε between the calculated average value and the target pavement thickness ε.
= T _a −T ₀ is calculated every time the vehicle 1 travels a measured distance, for example, 5 m, and when the difference becomes larger than a certain value, the control target value L ₁ of the third height sensor 19 is calculated. To correct the constant α ₀ used for here,
Height difference δ ₁ , δ ₂ , between two measurement points P ₁ , P ₂ , P ₂ , P ₃ , P ₃ , P _4, ... Simultaneously measured by a pair of height sensors 13, 14.
A method for calculating δ ₃ ... And a method for calculating the pavement thickness t at each of the measurement points P ₁ , P _2, ... Will be described with reference to FIGS. 4 and 5.

The height difference δ is calculated by the following equation.

δ = H _2- (H ₁ -Mtan θ ₁ ) (1) Here, the above signs have the following meanings.

H ₁ : value detected by the first height sensor H ₂ : value detected by the second height sensor M: distance between the first and second height sensors θ ₁ : inclination of the measuring arm 12 The pavement thickness t is calculated by the following equation.

T = H ₂₁ + δ−Mtan θ ₂ −H ₀ (2) Here, the above-mentioned symbols have the following meanings.

H ₂₁ : Value detected by the second height sensor δ: Value calculated by the above formula (1) M: Same as above θ ₂ : Tilt of measuring arm H ₀ : Height difference between height sensor and screed The above formulas (1) and (2) are shown for the sake of easy understanding of the method of calculating the height difference δ and the pavement thickness t, and the measuring device 11 shown by the asphalt finisher AF shown in FIGS. 1 and 3 is used. Slightly different from Actually, in order to perform the measurement by the measuring device 11 of the present embodiment, the vehicle 1 uses the screed 5
The height difference δ and the pavement thickness t are calculated every time the two height sensors 13 and 14 travel the distance, not the distance between the height sensor 14 and the second height sensor 14 (see FIG. 5).

In the above calculation formulas (1) and (2), since the height difference δ and the pavement thickness t do not consider the inclination θ, there is a slight difference from the actual value, but the inclination θ is extremely small. Can be ignored.

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, the asphalt mixture in the hopper 2 is sent to the screw by the feeder and spread evenly in front of the screed 5. Spread the mix with screed 5 and level it.

In the above, the traveling distance of the vehicle 1 is measured by the distance sensor 17, and the first and second traveling distances are calculated every time the traveling distance becomes M.
The height sensors 13, 14 measure the distance from the roadbed surface and output the measurement result to the arithmetic unit 30.

The computing device 30 computes the height difference δ and the pavement thickness t from the output signals of the height sensors 13 and 14, the distance sensor 17, and the inclination sensor 15 as described above. Then, the reference flat line y = ax + b is calculated based on these values. When the reference flat line is calculated, it is calculated from four points (P _{1 to} P ₄ ) on the front unpaved surface of the screed 5 as shown in FIG. 3, for example.

Then, the difference E between the calculated reference flat line and the upper part of the roadbed at the first measurement point in front of the screed 5 is obtained.
Specifically, it is calculated by the following formula.

E = δ ₁ − (ax + b) (3) Further, the constant α ₀ used to calculate the control target value L ₁ measured by the third height sensor 19 is obtained. This constant α ₀ is
Specifically, in the initial operation of the asphalt finisher, when a predetermined switch is pressed when the operator determines that the steady state is reached, E ₀ + L ₀
Is required. Those values are input to the data storage unit 34.

Then, the calculated value E is subtracted from the obtained constant α ₀ to calculate the control target value L ₁ measured by the third sensor 19.

After that, the difference between the control target value L ₁ and the actual measured value L is obtained, and the variation amount of the screed 5 is determined so that the difference is eliminated. Then, the signal output from the arithmetic unit 33 is sent to the solenoid valve 37 via the I / O interface 36, and the pivot cylinder 8 is expanded / contracted to control the screed 5.

That is, the screed 5 so that E + L is always constant
To control. This ensures the flatness of the finished surface of the pavement.

The above operation is repeated every time the vehicle 1 travels the distance M. That is, in FIG. 3, after the screed 5 reaches P ₁ , the next points P ₂ , P ₃ , P ₄ , and P ₅ become the reference points, and from there, the reference flat line and the difference between the reference flat line and the roadbed. Etc., and the screed 5 is controlled.

On the other hand, every time the vehicle travels for a predetermined distance, the pavement thickness check calculation unit 35 determines whether the actual pavement thickness deviates greatly from the target pavement thickness, and if the difference exceeds a certain range, a constant α ₀ Is corrected.

Therefore, in the asphalt finisher of the present embodiment, not only the flatness is secured, but also the pavement thickness can be brought close to the target pavement thickness.

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

(1) In the above embodiment, the separation distance between the height sensors 13 and 14 is set to M, but the present invention is not limited to this, and 2M
Alternatively, it may be set to M / 3 or the like.

(2) The height sensors 13, 14, 19 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 latest 4 points after pavement are used to calculate the reference flat line by the least squares method, but the present invention is not limited to this, and the latest 3 points or 5
You may calculate based on a point.

〔The invention's effect〕

In the present invention according to claim 1, a reference flat line is formed from a plurality of measurement points on the unpaved surface by the method of least squares, and along the reference flat line (the height positional relationship with the reference flat line is always maintained. ) Since it is paved, it is possible to realize paving using such a device without using a separate device such as a long ski described in the prior art, and thus to be affected by the unevenness of the unpaved surface. Without it, you can finish a flat paved surface.

Further, according to the invention of claim 2, the flatness of the pavement surface can be secured, and the pavement thickness can be brought close to a desired value, which is an excellent effect.

[Brief description of drawings]

The accompanying drawings show an embodiment of the present invention. 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. Figures for explanation, Figures 4 (a) and 4 (b) are illustrations for obtaining the height difference of the roadbed and pavement thickness, and Figures 5 (a), 5 (b) and 5 (c) correspond to the examples. FIG. 8 is an explanatory diagram for obtaining a pavement thickness with a good height difference of the roadbed. 1 ... Vehicle, 5 ... Screed, 8 ... Pivot cylinder, 11 ... Measuring device, 13 ... First height sensor, 14 ...
Second height sensor, 15 ... Inclination sensor, 17 ... Distance sensor, 19 ... Third height sensor, 30 ... Control device, y ...
Reference flat line, E ... Difference (deviation amount) between the reference flat line and the roadbed.

Front page continued (72) Inventor Tetsuo Ogawa 730, Mitsutaka, Gunma-cho, Gunma-gun, Gunma Prefecture Niigata Iron Works Takasaki Plant (72) Inventor Tomohiro Gomachi 1-19-11 Kyobashi, Chuo-ku, Tokyo Japan Inside the Road Co., Ltd. (72) Inventor Ikama Yamabe 1-19-11 Kyobashi, Chuo-ku, Tokyo Japan Tappo Inside (72) Inventor Ichiro Miyazaki 1-19-11 Kyobashi, Chuo-ku, Tokyo Japan Tamaido Within the corporation (56) References JP-A-63-272803 (JP, A) JP-A-1-295902 (JP, A)

Claims (2)

[Claims] 1. A pavement thickness control method in a leveling machine for controlling the thickness of a 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. A pair of height sensors are provided on the leveling machine at a predetermined interval in the traveling direction, and an inclination sensor for measuring the inclination angle of the pair of height sensors is provided, and the leveling machine is provided on the leveling machine. Based on the output signal from the distance sensor, the leveling machine measures the height of the unpaved surface by the pair of height sensors and the inclination sensor every time the leveling machine travels the separated distance of the pair of height sensors, and then from those values. A standard flat line is created by introducing the least squares method, and a deviation amount of the unpaved surface from the standard flat line at a target point ahead of the screed by a predetermined distance in the traveling direction is obtained,
A pavement thickness control method for a leveling machine, characterized in that the screed is controlled according to the amount of deviation. 2. The pair of height sensors are connected to a screed, and the pavement thickness of the paved surface is calculated from the measured value of the unpaved surface measured by the height sensor. The average value of the screed is compared with a predetermined target pavement thickness, and the result is fed back to control the screed while periodically correcting the deviation amount. Method for controlling pavement thickness in machine.