GROUND COMPACTION SYSTEM FOR COMPACTING ASPHALT MATERIAL AND METHOD FOR COMPACTING ASPHALT MATERIAL

Description

The present invention relates to a ground compaction system by which asphalt material can be compacted, for example in road construction.

From EP 3 124 698 A1 a ground compaction system is known in which information is displayed on an asphalt paver on a display screen which shows to an operator of a ground compactor which compacts the asphalt material applied behind the asphalt paver, how close the ground compactor should be at most to the asphalt paver or how far away it should be at most from it. This information is generated based on a temperature of the applied asphalt material recorded at the asphalt paver. In an alternative design, lines are projected onto the asphalt material, indicating to the operator the region in which the ground compactor should move on the applied asphalt material. These lines are also detected taking into account the temperature of the asphalt material being applied, as detected on the asphalt paver.

It is the object of the present invention to provide a ground compaction system for compacting asphalt material and a method for compacting asphalt material by means of such a ground compaction system, with which the precise execution of a compaction operation is made easier to an operator of a ground compactor.

According to the invention, this object is achieved by a ground compaction system for compacting asphalt material, comprising:

• • at least one ground compactor to be moved on the asphalt material to be compacted,
  • at least one display unit with a display for displaying compaction operation information related to a ground compaction process to be carried out,

wherein the at least one display unit is designed to display on the display at least one reversal limit in connection with a movement of the at least one ground compactor on the asphalt material to be compacted, wherein the at least one reversal limit indicates a limit for the movement of the at least one ground compactor in a direction of movement.

By displaying at least one such reversal limit, an operator of a ground compactor is shown directly, without having to observe the asphalt material to be compacted and/or an asphalt paver moving ahead, the position to which the ground compactor operated by that operator can be moved before the direction of movement must be reversed. The operator therefore does not have to estimate the position of the ground compactor, for example in relation to the surroundings or an asphalt paver applying the asphalt material, so that resulting sources of error when carrying out a compaction operation can be eliminated.

Since, when compacting asphalt material, a ground compactor is generally moved back and forth in directions of movement that are substantially opposite to one another, it is particularly advantageous if the at least one display unit is designed to display, in connection with the movement of the at least one ground compactor, a respective reversal limit for each of two substantially opposite directions of movement of the at least one ground compactor.

In order to ensure that measures for braking and reversing the direction of movement of the at least one ground compactor can be initiated in good time before reaching a reversal limit, the at least one display unit can be designed to display a distance of the at least one ground compactor from the reversal limit in association with at least one, preferably each, reversal limit.

Since the temperature of the asphalt material is an important influencing parameter for whether the asphalt material can already be compacted or can still be compacted, it is advantageous for the operator operating the at least one ground compactor if the at least one display unit is designed to display a temperature of the asphalt material in the region of the reversal limit in association with at least one, preferably each, reversal limit. This allows the operator to estimate whether a reversal limit which is predetermined or shown on the display is plausible, possibly taking into account any additional information displayed to the operator.

In order to make it easier for the operator to assess the current position of the ground compactor operated by the operator, it is proposed that the at least one display unit is designed to display, in association with the at least one ground compactor, the crossing tracks that are to be crossed or/and are crossed by the ground compactor.

For data processing or for generating the data underlying the information to be displayed, an information processing unit for generating the compaction operation information on the basis of asphalt temperature information representing a temperature of the asphalt material to be compacted can be provided.

It is particularly advantageous for precise compaction of the asphalt material if the information processing unit is designed to generate the compaction operation information on the basis of at least one temperature influencing parameter influencing the temperature of the asphalt material to be compacted.

The at least one temperature influencing parameter may, for example, comprise:

• • an ambient temperature;

or/and

• • an air humidity,

or/and

• • a wind speed,

or/and

• • a ground temperature,

or/and

• • an amount of precipitation and/or a type of precipitation.

Since the asphalt material to be compacted itself is also an essential influencing parameter for a compaction operation to be carried out, it is further proposed that the information processing unit is designed to generate the compaction operation information on the basis of at least one material parameter of the asphalt material to be compacted.

The at least one material parameter may, for example, comprise:

• • a thickness of the asphalt material before compaction,

or/and

• • a thickness of the compacted asphalt material,

or/and

• • a compaction state of the asphalt material.

The design of a ground compactor used for compaction also significantly influences the characteristics of the ground processing operation being carried out or to be carried out. For this reason, it is further proposed that the information processing unit is designed to generate the compaction operation information on the basis of at least one compactor parameter characterizing the at least one ground compactor.

The at least one compactor parameter may, for example, comprise:

• • a mass of the at least one ground compactor,

or/and

• • an extension length of at least one compactor roller of the at least one ground compactor in the direction of a roller rotation axis,

or/and

• • a compaction performance of the at least one ground compactor.

For applying the asphalt material to be compacted by the at least one ground compactor, the ground compaction system according to the invention can comprise at least one asphalt paver.

In order to be able to generate the information representing the temperature of the asphalt material, which is a particularly important parameter for a compaction operation, a temperature detection arrangement for providing asphalt temperature information representing the temperature of the asphalt material applied by means of the at least one asphalt paver can be provided on the at least one asphalt paver.

The invention further relates to a method for compacting asphalt material by means of a ground compaction system constructed according to the invention, in which method at least one reversal limit representing a limit for a movement of the at least one ground compactor in a direction of movement is displayed on the display of the at least one display unit.

The present invention is described in detail below with reference to the attached figures. In particular:

FIG. 1 shows a side view of a ground compactor;

FIG. 2 shows a schematic representation of a ground compaction system comprising an asphalt paver and a ground compactor;

FIG. 3 shows a display of a display unit with compaction operation information displayed thereon.

In FIG. 1, a ground compactor 10 used to compact ground material, in particular asphalt material, is shown in side view. The ground compactor 10 comprises a rear carriage 12 with drive wheels 14 provided thereon and driven for rotation by a drive unit in order to move the ground compactor 10 on the asphalt material 16 to be compacted. In addition, an operating station 18 for an operator 20 operating the ground compactor 10 is provided on the rear carriage 12.

A front carriage 22 is pivotally connected to the rear carriage 12 about a steering axis for steering the ground compactor 10. On the front carriage 22, a compactor roller 24 is rotatably supported about a roller axis of rotation which is perpendicular to the drawing plane of FIG. 1.

It should be noted that the ground compactor 10 may also have, for example, two compactor rollers and may be designed, for example, as a pivot-steered compactor. One or more of the compactor rollers of the ground compactor 10 can be associated with a vibration generating arrangement, by means of which the compactor roller can either be subjected to a vibrating movement, i.e. an oscillating movement substantially orthogonal to the roller axis of rotation, or can be subjected thereto to perform an oscillating movement, i.e. a back and forth movement about the roller axis of rotation.

FIG. 2 illustrates in principle a ground compaction system 26 which, in addition to the ground compactor 10, comprises an asphalt paver 28 through which the asphalt material 16 to be compacted by the ground compactor 10 is applied. The asphalt paver 28, which is designed, for example, with crawler tracks 30, comprises a paver screed 32 which is positioned in a rear region of the asphalt paver 28 with respect to a direction of movement B1 of the asphalt paver when the asphalt material 16 is being applied, by means of which the asphalt material 16 is applied onto a prepared ground surface 34.

During compaction operation, the ground compactor 10 generally moves back and forth in the direction of movement B₁ of the asphalt paver 28 and in an opposite direction of movement B₂ and thus travels over the asphalt material to be compacted along multiple crossing tracks, for example predetermined by a compaction plan, if necessary multiple times.

In order to enable the operator 20 to move the ground compactor 10 in a defined manner on the asphalt material 16 to be compacted, the ground compaction system 26 comprises a display unit 36, shown in principle in FIG. 3, with a display 38. The display unit 36 can, for example, comprise a smartphone, a tablet or the like, i.e. can be essentially mobile and carried by the operator 20, or can be permanently installed in the operating station 18.

By means of the display unit 36, compaction operation information is shown on the display 38, which indicates to the operator 20 where the ground compactor 10 is positioned, in particular with respect to the asphalt paver 28, and how the ground compactor 10 should be moved on the applied asphalt material 26.

It can be seen in particular from FIG. 3 that the compaction operation information comprises the crossing tracks 40 on which the ground compactor 10 is to be moved according to a, for example, fixedly predetermined compaction plan behind the asphalt paver 28 moving in the direction of movement B₁ either in the same direction of movement B₁ or in the opposite direction of movement B₂.

The position of the asphalt paver 28 and of the ground compactor 10 can be detected, for example, by a satellite-based or, if appropriate, a ground-based position detection system 42. This information is processed in an information processing unit 44, for example, provided or stationed on the asphalt paver 28, in such a way that it can be displayed by the display unit 36 on the display 38. The data of a compaction plan, from which the course of the crossing tracks emerges, can also be processed in the information processing unit 44 in such a way that the crossing tracks 40 can be displayed on the display 38.

A temperature detection arrangement, generally designated 46, is provided on the asphalt paver 28. The temperature detection arrangement 46 can comprise a plurality of temperature sensors 48 provided on the asphalt paver 28, in particular the paver screed 32 thereof, which generate asphalt temperature information representing the temperature of the asphalt material 16 applied by means of the paver screed 32 substantially over the entire width of the paver screed 32 and transmit it to the information processing unit 44.

The temperature of the applied asphalt material 16 is an important parameter for whether the asphalt material 16 is already or should still be compacted by means of the ground compactor 10. If the asphalt temperature is too high or too low, the asphalt material 16 cannot be compacted with the desired quality. It is therefore important that the ground compactor 10 moves behind the asphalt paver 28 only in a region in which it is ensured that the gradually cooling asphalt material 16 has a temperature suitable for carrying out a compaction process.

Taking into account the asphalt temperature information, the information processing unit also generates reversal limits 50, 52 in association with the spatial position of the ground compactor 10, which limits are displayed on the display 38 in association with the ground compactor 10 and indicate how far the ground compactor 10 may or should move towards the asphalt paver in the direction of movement B₁ or away from the asphalt paver 28 in the direction of movement B₂. For example, in association with these reversal limits 50, 52, the display can also show how far a respective reversal limit 50 or 52 is currently away from the ground compactor 10, so that the operator 20 can initiate a braking process in good time and can thus ensure that at or shortly before reaching a respective reversal limit 50, 52, the direction of movement of the ground compactor 10 is reversed and, if necessary, changes to a subsequent crossing track 40 in accordance with the specified compaction plan. Furthermore, in association with a respective reversal limit 50, 52, it can be displayed which temperature the asphalt material has at the respective reversal limit 50, 52. For example, a temperature averaged over the width of the asphalt paver 28 or a temperature detected by a temperature sensor 48 positioned closest to the currently traversed crossing track 40 can be displayed.

In FIG. 3 it can further be seen that at the reversal limit 50 located closer to the asphalt paver 28 the temperature of the asphalt material 16 is in the range of approximately 140° C., while at the reversal limit further away from the asphalt paver 28 the asphalt material has already cooled down to 80° C. Since the temperature of the asphalt material 16 is detected immediately behind the asphalt paver 28, i.e. at a significant spatial distance from the reversal limits 50, 52, by means of the temperature detection arrangement 46, the temperature of the asphalt material 16 at an increasing distance from the asphalt paver 28 can be determined mathematically by means of the information processing unit 44, for example on the basis of a model representing the cooling behavior of the asphalt material 16. In this calculation, various temperature parameters influencing the cooling behavior of the asphalt material, such as the ambient temperature, the air humidity, the wind speed, the temperature of the ground 34 or even the amount or type of precipitation, i.e. rain or snow, can be taken into account. In this way, it is possible to determine the temperature relatively accurately at locations that were already passed over by asphalt paver 28 some time before.

Material parameters of the applied asphalt material 16 itself also influence the cooling behavior of the asphalt material 16 and can therefore be taken into account when determining the reversal limits. For example, the thickness of the asphalt material that has not yet been compacted, the thickness of the asphalt material that has already been compacted, or the compaction state of the asphalt material can be taken into account. The thickness of the compacted asphalt material and its compaction state can be determined in a manner known per se from operating variables of the ground compactor 10 that characterize the compaction state, such as the acceleration of a compactor roller in the vertical direction and in the horizontal direction and the movement speed of the ground compactor 10.

Parameters characterizing the ground compactor 10 itself have a further influence on the required maximum or minimum temperature of the asphalt material 16 to be compacted by the ground compactor 10. For example, its mass, the contact length, i.e. the extension length of one or more compactor rollers of the ground compactor 10 in the direction of a respective roller rotation axis as well as its compaction performance can be taken into account. The compaction performance can be determined, for example, on the basis of whether the ground compactor 10 has a vibration generating arrangement associated with one or more compactor rollers, i.e. whether compaction can be carried out in vibration mode and/or in oscillation mode.

FIG. 3 illustrates that further information 54, 56, which is only shown in principle, can be displayed on the display 38. These may include, for example, environmental parameters such as the ambient temperature, the air humidity or the like, but may also include the speed of movement of the ground compactor 10 and its current operating mode, for example whether compaction is taking place in vibration mode, oscillation mode or static mode. It can also be displayed whether or to which of the crossing tracks 40 also shown on the display 38 a change should take place after the next change of direction. Furthermore, it is possible to display variables that characterize the compaction state of the asphalt material, such as its density or the like.