EP3456878B1 - Method for monitoring the compression process in road construction and street roller - Google Patents

Description

The invention relates to a method for monitoring the compaction process of an asphalt layer to be compacted in road construction. Moreover, the invention relates to a road roller, in particular tandem roller, compactor or rubber wheel, for carrying out the method.

In road construction, hot asphalt is usually distributed by a paver across the width of a planned course of the road, smoothly drawn off and precompressed, for example with a tamper strip and / or a screed. Furthermore, as long as the asphalt material is still hot and deformable, the new road surface is usually further compacted by road pavers following road rollers, which are for example designed as tandem rollers, compactors or rubber wheeled rollers. Only at an optimal degree of compaction do roads reach their maximum service life. Both too low and too strong compaction lead to a reduced durability of the road surface and thus to a reduced quality of the road created. In order to achieve a uniform as possible compaction of the asphalt layer, the operators of the road rollers are usually set to the width of the asphalt layer to be compacted rolling schemes with history and number of crossings to be performed for each road construction project. How evenly the compaction of the entire road surface actually succeeds depends crucially on how consistently the operators of the road rollers adhere to the intended rolling schedule. The aim of these rolling schemes is to compress the road surface in its width and length as evenly as possible.

However, adherence to the rolling schedule is not the only aspect that operators of road rollers must pay attention to. For example, they also have to agree with others Coordinate rollers and keep track of the progress of the paver. In addition, the rollers must be particularly precisely controlled, especially in the edge region of the asphalt layer, since they should also create, for example, with side mounted on the road rollers Andrückrollen a straight, sharp edge of the road. It may therefore be that in working mode certain regions of the asphalt layer to be compacted are more compacted than others. It often happens, for example, that the edge areas of the asphalt layer are run over by the operators of the road rollers less often than central areas. The result is a non-uniform compaction of the road and thus a reduced quality of the finished cover layer.

In the prior art, several strategies are known to ensure optimum compaction of the asphalt layers. For example, systems are known in which by means of GPS ( global positioning system ) can be tracked as accurately as possible, at which points of the asphalt layer, the road rollers have already compacted and at which points is still further to compact. Systems are known in which the entire construction site is mapped in this manner and displayed to the operator of the road roller as a three-dimensional topography with different colors to identify areas of different densities. In order to allow sufficiently accurate position determination of the road roller, a not inconsiderable expenditure on equipment and financial resources is required. From the US 6,749,364 B1 For example, a system is known in which the road rollers are equipped with a thermal imaging camera which produces a thermal profile of the asphalt pavement laid by the paver and indicates to the operator of the road roller so that he knows where the asphalt layer currently has the optimum temperature for compaction. Here, therefore, the rolling pattern is adapted to the actual events with respect to the respective current temperature of the asphalt layer. Also in the US 6,749,364 B1 the position of the roller is determined by means of GPS or laser-based systems, for example with the aid of metered total stations. As a further prior art, the DE 10 2016 002064 A1 which also shows a method for monitoring a compaction process.

A disadvantage of the systems of the prior art is that they require a high technical complexity and are associated with increased acquisition costs and sometimes running costs. In addition, a deviation from the planned rolling schedule due to the temperature profile of the asphalt layer carries the risk that different areas are compressed to different degrees.

It is therefore an object of the present invention to provide a method and a road roller with which a monitoring of the compaction process of an asphalt layer to be compacted in road construction succeeds, so that overall the compaction quality can be improved. At the same time the operator of the road roller to be relieved of the exact monitoring of compliance with the rolling schedule, so that it can concentrate on the control of the road roller. Another object of the present invention is that the monitoring of the compression process with the least possible technical effort and therefore should be particularly cost-effective.

The solution to this problem is achieved with the method and the road roller according to the independent claims. Preferred developments are specified in the dependent claims.

Specifically, the solution thus succeeds with a method for monitoring the compaction process of an asphalt layer to be compacted in road construction, comprising the steps of: detecting edges bordering the hot asphalt layer perpendicular to the road by means of a temperature sensor arranged on a road roller compacting the asphalt layer, and subdividing the detected asphalt layer in at least two width segments across the street. The width segments are defined by their distance from the edges of the asphalt layer. The invention now provides that the position of the road roller on the asphalt layer across the road is determined from the measurement of the temperature sensor and assigned to one of the width segments, that the working operation of the road roller on the respective width segment is quantified and stored by an operating parameter, and that in particular to the operator of the road roller, for at least one past working interval the quantified work operation is displayed for each latitude segment. The essential basic idea of the invention is to provide a simple system which gives the operator of the road roller an overview of whether he has distributed the preceding operations uniformly over the entire width of the asphalt layer to be compacted, or whether he in relation to the width of to be compacted asphalt layer has more or less densified in one area than in other areas. However, this should not be done as in the prior art, a complicated and costly mapping of the entire work area. Rather, it should only be noted and displayed to the operator of the road roller how evenly the work of the road roller has been distributed over the entire width of the asphalt layer to be compacted in a just completed working interval, so that the operator may be able to adjust his operation if it turns out that the asphalt layer would otherwise be unevenly compacted. Ultimately, it is thus counted how long and / or how often the roller is in one of the defined width segments. Accordingly, the current position of the road roller must be known and documented only in relation to the width of the asphalt layer to be compacted. It is not necessary to know the position of the road roller also in the longitudinal direction of the road. The longitudinal direction of the course of the road designates the longitudinal extent of the road surface to be compacted by the roller in the working and travel direction of the paver. On the other hand, the roller is generally moved reversely in and counter to this working and traveling direction for compacting purposes over the road surface. Typically, more than one roller pass is sought to obtain a desired compaction result.

In practice, a paver moves the asphalt layer to be compacted more or less continuously forward in its working direction. The road rollers following the road paver then run over the freshly laid asphalt and, with frequent reversing runs, follow the set rolling schedule in the best possible way. At the same time, the working area of the road rollers also shifts substantially continuously forward, i. The road rollers travel with the considerably slow moving paver in the installation process. According to the invention, it is now detected by means of the temperature sensor in which width segment of the asphalt layer the road roller just compresses the asphalt. This data is stored and evaluated statistically over at least one working interval, so that the operator can be shown what proportion of the compaction work within the working interval has dropped to which latitude segment. If the operator of the road roller keeps exactly to the rolling schedule, all width segments of the asphalt layer should have been evenly compacted. A deviation from the uniform distribution, for example, because the road roller in a latitude segment has run over the asphalt layer more often than in another width segment would thus be indicated to the operator by an uneven distribution of compaction work on the latitudinal segments so that it can adapt its operation to an uneven Avoid compaction during further operation.

The invention makes use of the fact that asphalt is installed by road pavers when hot. This always results in a strong difference in temperature between the built-in and to be compacted asphalt layer and lying next to the asphalt layer ground, which is significantly colder than the asphalt. This can be used by the temperature sensor according to the invention, which is in particular a non-contact temperature sensor, the position of the edges of the hot asphalt layer, ie the position of the transition between hot asphalt layer and cold ground background next to the road, and the position of the roller in dependence on at least one Detected page margin calculated, in particular by means of a suitable control unit to determine. According to the invention, the temperature sensor is designed such that it allows a temperature detection of the asphalt layer in a width which is wider than the rolling width the respective road roller is. If the temperature sensor has determined the edges of the asphalt layer which run parallel to the longitudinal extent of the road, then the asphalt layer can be computationally divided into width segments transversely to the roadway. Moreover, since the position of the temperature sensor on the road roller is known, from the continuous measurement of the temperature sensor, the current position of the road roller can be assigned to one of the width segments. In other words, the position of the road roller is determined with respect to the width of the asphalt layer to be compacted. The invention thus utilizes that the position of the road roller can be determined transversely to the course of the road from the measurements of the temperature sensor. In this way, no, for example, GPS or laser-based, more complex and expensive systems are needed. Finally, at least one detected edge area of the asphalt layer to be compacted is used to identify the position of the roller with respect to the width of the asphalt layer to be compacted. The determination of the width segments, in particular the definition of the position and the number of width segments on the asphalt strip, can be carried out as already described after the detection of the hot asphalt layer by the temperature sensor. However, it is also possible that initially only the position of the road roller on the asphalt layer is determined by the measurement of the temperature sensor, without assigning this position equal to a width segment. The division into width segments and the corresponding assignment of the specific position of the road roller to the respective width segments, for example, also only in a downstream evaluation step, for example, during the statistical evaluation of the quantified work operation done. It is therefore not according to the invention explicitly on the above-described sequence of process steps.

In order to give the operator of the road roller assistance for monitoring the course of the compression process, it is registered according to the invention in which width segment the road roller has yielded much compaction power relative to a past working interval. In this case, the working operation of the road roller is quantified on the respective width segment by an operating parameter, as will be explained in more detail below. The distribution of the compaction power or the working operation of the road roller on the width segments is displayed to the operator, so that he can take care to make the distribution as evenly as possible and thus to achieve a uniform compaction of the asphalt layer.

Basically, it is sufficient to use a temperature sensor that can determine the temperature at a single point. By pivoting or moving the temperature sensor can determine the temperature on a line across the road. In this case, the temperature sensor detects a temperature jump when its measuring point is an edge of Crossed asphalt layer. On the basis of the movement or pivoting direction of the temperature sensor and the sign of the temperature change can be determined whether it is the right or the left edge of the asphalt strip. In such a temperature sensor, it is preferable that detection of the edges bordering the hot asphalt layer on the roadway by the temperature sensor is performed periodically in succession. In other words, the measurement is repeated periodically and continuously during operation, so that at any time the position of the edges or at least one edge of the asphalt layer to be compacted are known and thus the position of the road roller with respect to the width segments can be determined. Alternatively, however, it is preferred that both edges are detected simultaneously by the temperature sensor. For this it is necessary that the temperature sensor has several measuring points. For example, the temperature sensor may be formed as a thermal image or infrared camera with a resolution of several pixels. In this case, it is preferable that the temperature sensor or the thermal imager is arranged on the road roller so that it can absorb the entire width of the asphalt strip in an image setting. In this way it is also particularly easy to determine from the image of the thermal camera, from which emerge the edges of the asphalt strip, in which width segment the road roller is currently located. For example, this is already possible with an accuracy of approximately 1 m for thermal imaging cameras that only have 16x4 pixels. Such thermal imaging cameras are inexpensive and are therefore particularly suitable for the invention.

Regardless of how the temperature sensor used is constructed concretely, it is preferred if the measuring width of the temperature sensor at least corresponds to or preferably is greater than the width of the asphalt layer to be compacted. For the reliable implementation of the method according to the invention, it is advantageous if the position of the roller with respect to the width of the asphalt surface to be compacted can be determined at any time. This succeeds when ideally always an edge of the two edges of the asphalt layer is in the detection range or within the measuring width of the temperature sensor. In order to enable this regardless of the position of the roller in the width, the measuring width of the temperature sensor is preferably at least as large as the width of the asphalt layer to be compacted. If the roller works in the edge region of the asphalt layer to be compacted, it may be that only this edge is detected by the temperature sensor, since the detection range is no longer sufficient to detect the farther edge region. In this case, the previously determined total width of the asphalt layer can be used as a substitute, since in the majority of cases the pave width of the road finisher only changes insignificantly. By the alternative use of the pave width, the at favorable roller position was determined, it is sufficient if the measuring width of the temperature sensor is slightly larger than the width of the hot asphalt layer.

In principle, it can be determined via many different parameters, which are all proportional to the compaction performance or to the compaction work of the road roller, how much the road roller has compacted the asphalt layer, in particular statistically, in a width segment. Preferably, at least one of the following parameters is used as the operating parameter: a time span, a number of passages, a number of reversing runs, a covered distance, a background stiffness and / or a vibration intensity of a roller drum of the road roller. Wherein the vibration intensity can be described by a variety of parameters. For example, based on the vibration amplitude, vibration acceleration, number of oscillations per distance traveled or centrifugal force. All these parameters are suitable for quantitatively detecting the working operation of the road roller on the respective latitude segment. Thus, for example, it can be determined how much time the road roller spends on the respective width segment, how often it passes over the respective width segment or how often it changes the direction of travel on the respective width segments, what distance the road roller traveled on the respective width segment or with what intensity a vibration exciter is operated, which puts the roller drum of the road roller in vibration or oscillations to enhance the compaction performance. For example, for the display to the operator, the corresponding parameters may be used as absolute values added over time. Thus, for example, it would be possible to display how much time of the preceding work interval the road roller has spent on which width segments or how far the road roller traveled on the corresponding width segments. In addition, however, a relation of the individual width segments could be displayed among each other. For example, it could be displayed what percentage of the compaction work or the work of the road roller was performed in the past working interval in the respective latitude segment. Of course, it is also conceivable to carry out the quantification of the working operation via a combination of two or more of the mentioned parameters. For example, it is advisable to combine the used vibration intensity of the roller bandage, which enhances the compression, with one of the other parameters. In this way, the compaction performance of the road roller in the individual width segments can be weighted by the respective vibration intensity and lead to a more accurate picture of the uniformity of the compaction achieved by the road roller. Alternatively, additionally determined in the respective width segments Substrate stiffness used to assess the compaction performed by the roller.

The past working interval according to the invention relates to a past section of the working operation. Preferably, the same operating parameters as for the quantification of the work operation and / or another parameter are used to establish limits of the past work interval. That is, the past working interval includes, for example, a certain period of time, a certain number of crossings, a certain number of reversing operations and / or a certain distance traveled. Of course, combinations of the individual parameters are also possible here. For example, the past working interval could thus refer to a period of 10 minutes of the working operation of the road roller. According to the invention, the operator is then then, following a recording phase within the first 10 minutes after the start of work displayed to what extent he has the working operation of the road roller within these temporally past 10 minutes on the respective width segments absolutely or relatively distributed. It can be provided that the past working interval refers to the same or the same parameters as the quantification of the working operation. For example, the operator could thus be shown what percentage of the last 10 minutes of the work operation has spent the road roller on the respective width segments. However, it is also possible that different parameters are used to quantify the work operation and to determine the past work interval. For example, the quantification of the work operation can be done via the number of passes, while the past work interval is related to the elapsed time. For example, the operator would then be shown what percentage of the crossings of the last 10 minutes of the last work interval to which width segments omitted. Here are all combinations of the mentioned parameters conceivable.

In principle, successive working intervals could each be statistically evaluated separately and the respective results displayed to the operator of the road roller, for example separately and successively, in each case when a working interval has been completed. In this way, however, the operator is made aware, in retrospect, of any irregularities in the compaction process. It is therefore preferred that the parameter or parameters used for quantifying the operating mode is / are stored within the working interval, wherein in the operating mode those data which lie further than the working interval are replaced by newly recorded data. In other words, both the recording of the data and their statistical evaluation is carried out continuously. The past working interval is therefore always close to the present and includes, depending on the parameters, for example, the last 10 minutes of operation. The position in which the road roller is transverse to the road, in real time in the statistical evaluation, while data that is more than the predetermined working interval, are removed from the statistics. The operator of the road roller can thus also observe the development of the statistics in real time and thus sees in advance when there is a shift in the working performance of the road roller or an inequality between the individual width segments. In this way, the driver always has an up-to-date feedback on his current workflow and always has the uniformity of the compression in view, without having to concentrate on strict compliance with the rolling schedule. Imminent inequalities can be counteracted at an early stage.

The classification of the detected asphalt layer in width segments can be done differently depending on the application. The aim of the invention is to determine in which lane on the asphalt layer the road roller is currently located. The definition of the lane or of the latitude segment takes place via the distance from the cold roadway edge, which is detected by the temperature sensor. In principle, a higher accuracy is achieved when dividing the asphalt layer into many width segments across the road. On the other hand, the accuracy of the system is also limited by the accuracy of the temperature sensor, for example by the number of pixels of the thermal imager. The aim of the invention is not a millimeter accurate mapping of the asphalt layer, but an orientation guide for the operator of the road roller. An exact evaluation with high accuracy is not necessary for this purpose. For example, it is preferable that the detected asphalt layer is divided at least into the three width segments "left side", "middle" and "right side" across the road. In this way, it is possible to prevent the side edge areas of the asphalt layer from being compacted less strongly than the areas in the middle of the asphalt layer. The exact number of width segments may also, for example, be fixed to the total width of the asphalt layer to be compacted with respect to the width of the road roller, in particular the width of its roller bandage. For example, the asphalt layer can be subdivided into a number of width segments equal to the number of times the roller drum of the road roller fits next to each other in the asphalt layer, possibly also taking into account a typical overlap of approximately 10 cm between the individual lanes. As already mentioned, however, the exact determination of the overlap width is not required.

According to a preferred embodiment, it is provided that the width segments, in particular all width segments, are the same across the road. In this way, the working operation of the road roller in the respective width segments for all areas of the asphalt layer is considered equally strong. Alternatively, it is also possible that those width segments that lie at the edges of the detected asphalt layer, are transverse to the road less broad than width segments that lie in the middle of the detected asphalt layer. In this way, a higher resolution of the monitoring according to the invention is achieved especially at the edges of the asphalt layer. This is particularly advantageous when too low compression at the edges of the asphalt layer is to be feared, since then only an actual working operation of the road roller is counted in this area for the width segments at the edges of the asphalt layer.

In order to determine the position of the road roller on the asphalt layer across the road as accurately as possible, it is advantageous to additionally use various aspects of the arrangement of the temperature sensor and the working situation of the road roller. For example, it is preferred that when determining the position of the road roller on the asphalt layer, in particular transversely to the road, from the measurement of the temperature sensor, a measuring angle of the temperature sensor and / or a direction of travel and / or a steering angle and / or a steering mode, such as crab, the road roller is taken into account. The arrangement and thus the position of the temperature sensor on the road roller or the position of its measuring range relative to the other road roller are known. From the measuring angle of the temperature sensor, which can be either adjustable or constant, can thus be determined where the measuring range of the temperature sensor is, in particular in relation to the road roller itself. Especially when using a thermal imaging camera, the measuring angle of the temperature sensor leads to the asphalt layer, that the thermal image of the thermal camera is trapezoidal distorted. When evaluating the thermal image, care must therefore be taken that each pixel in the thermal image of the temperature sensor is assigned the correct real location on the asphalt layer or on the adjacent floor. For this purpose, each pixel of the thermal image is assigned a coordinate across and along the direction of travel or to the course of the road. The trapezoidal perspective distortion of the thermal image is taken into account taking into account the measuring angle and the arrangement of the temperature sensor on the road roller to close the real position of the asphalt layer. Such calculations are known from the image recognition, so it will not be discussed further here. Often road rollers are used, which have only one side of an additional device, such as a Kantenandrückrolle. Around these on both edges To use the asphalt layer, the road roller is therefore often rotated in operation by 180 ° and vice versa along the asphalt layer. So that in this situation, not the assignment of the sides, ie from the right and left, is confused, the direction of travel must also be taken into account, for example by using a digital compass that detects the current direction of travel of the road roller. Due to the additional consideration of the steering angle is achieved that in combination with the data of the temperature sensor, a change of the road roller from one latitudinal segment to another is foreseeable. A corresponding lane change can thus be predicted and thus recorded more accurately than purely in retrospect from the measurement data of the temperature sensor. In addition, road rollers can be operated in different types of steering. In the steering mode known as crabbing, for example, the road roller travels with roll collars offset parallel to one another, so that the working width of the road roller is increased. In this way, it may happen that the road roller then, for example, simultaneously processes two or even more width segments of the asphalt layer, depending on how finely divided the asphalt layer is divided into width segments. In order to take this into account in the statistics, the current steering mode of the road roller should also be included in the evaluation. The respective effective working width of the roller has an effect on the optimum rolling pattern, so that preferably a division of the asphalt layer into width segments takes place, which ensures optimum covering of the rolling tracks. For the best possible support of the roller driver, it is therefore advantageous if the number of necessary rolling tracks is displayed according to the installation width of the paver and the working width of the roller. Therefore, the method described above can also be used such that at least the total width of the surface to be compacted, the distance of the roller from at least one edge of the surface to be compacted and the working width of the roller is determined. From these values, the rollover of the area to be compacted is statistically recorded and later assigned to a certain number of rolling tracks.

The practical implementation of the method according to the invention is preferably carried out by means of a suitable control unit, in particular by means of a suitable control software, which carries out the necessary arithmetic operations for carrying out the individual method steps according to the invention.

The solution of the aforementioned object also succeeds with a road roller, in particular tandem roller, compactor or rubber wheel, for compaction of an asphalt layer in road construction, with a machine frame, a drive motor, a driver's cab, at least one roller drum and / or a wheel, a temperature sensor, and a Control unit, wherein the control unit for carrying out the method according to the invention described above is trained. All the above-mentioned features, effects and advantages of the method according to the invention also apply in a figurative sense to the road roller according to the invention. To avoid repetition, reference is therefore made to the above statements. The control unit is designed as a central processing unit and integrated, for example, in the on-board computer of the road roller. It is equipped with appropriate software to perform the method according to the invention.

As described above, it is preferable that the position of the road roller is continuously detected across the road and the evaluation statistic is updated continuously and in real time over the quantified operation distributed to the latitudinal segments, so that the past working interval is at any instant until the present moment and the operator always has an overview of the past working interval from that point in time. For technical implementation, it is preferred for this purpose that the control unit comprises a rolling memory which stores the quantified operating mode for each width segment within the past working interval. A rolling memory is characterized in that it stores data up to a certain limit, in particular temporal and / or space-dependent limit, and then deletes the oldest stored data continuously or rolling to record new data. In this way, the rolling memory continuously accepts current data and deletes the oldest data. As a result, the stored data always refer to the past working interval, which reaches to the present. The statistically evaluated data from the rolling memory therefore always represent the desired working interval. The size of the rolling memory is of course adapted to the desired size of the working interval.

Although different embodiments of the temperature sensor may be used to practice the invention, it is preferred if the temperature sensor comprises a thermal imaging camera. The invention makes no special demands on the corresponding thermal imaging cameras, so that particularly cost-effective models with comparatively low resolution can also be used. It is preferred if the thermal imaging camera has at least one resolution of two, in particular at least four pixels, transversely to the forward direction.

Figur 1:

eine Seitenansicht einer Tandemwalze;

Figur 2:

eine Seitenansicht eines Walzenzuges;

Figur 3:

eine seitliche Darstellung der Detektion der Asphaltschicht durch den Temperatursensor;

Figur 4:

eine prinzipielle Darstellung zur Umrechnung der Perspektive des Temperatursensors;

Figur 5:

ein Walzschema und dessen Registrierung;

Figur 6:

eine mögliche Anzeige der statistischen Auswertung;

Figur 7:

eine weitere mögliche Anzeige der statistischen Auswertung; und

Figur 8:

ein Ablaufdiagramm des Verfahrens.

The invention will now be explained in more detail with reference to the embodiments shown in FIGS. They show schematically:

FIG. 1:

a side view of a tandem roller;

FIG. 2:

a side view of a compactor;

FIG. 3:

a side view of the detection of the asphalt layer by the temperature sensor;

FIG. 4:

a schematic representation for the conversion of the perspective of the temperature sensor;

FIG. 5:

a rolling scheme and its registration;

FIG. 6:

a possible indication of the statistical evaluation;

FIG. 7:

another possible display of the statistical evaluation; and

FIG. 8:

a flowchart of the method.

Identical or equivalent components are numbered in the figures with the same reference numerals. Repetitive components are not designated separately in each figure.

The Figures 1 and 2 each show a road roller 1 with a driver's station 2 and a machine frame 3. In addition, the road rollers 1 to a drive motor 4, which is for example a diesel engine. FIG. 1 shows a tandem roller, which moves in working mode with its two roller bandages 5 on the bottom to be compacted 7. FIG. 2 shows a compactor, which has a wheat bandage 5 and additional wheels 6, with which the compactor moves over the bottom 7 to be compacted. In working mode, the road rollers perform 1 frequent Reversierfahrten so that they compress the ground 7 both in forward drive and in reverse. Just to clarify the description, the forward drive is indicated as indicated in the figures as working direction a, even if the road rollers 1 can also work in the opposite direction.

The road rollers 1 have a temperature sensor 8, which is arranged at the substantially highest point of the road rollers 1. In the exemplary embodiment shown, this is the roof of the driver's station 2. The temperature sensors 8 are, for example, thermal imaging cameras or infrared cameras. As shown by the dashed arrow, the temperature sensors 8 are aligned so that they receive the area in the working direction a in front of the road roller 1. Other arrangements and orientations of the temperature sensors 8, for example, an alignment of the measuring range against the working direction a, are possible. The angle a, in which the temperature sensor 8 is aligned in the working direction to the ground or against a perpendicular, is known. The temperature sensor 8 is connected to a control unit 9, which is located in particular in the driver's station 2 of the road roller 1. The control unit 9 is part the on-board computer of the road roller 1 and serves both for metrological and for statistical evaluation of the data collected by the temperature sensor 8. In addition, the control unit 9 is connected to a display device 10, via which the operator of the road roller 1, the statistical evaluation of the distribution of the quantified work operation on the width segments of the asphalt strip can be displayed. Of course, it can also be provided that the control unit 9 transmits the evaluated data by cable or wirelessly to another terminal, for example a smartphone or a tablet computer, wherein the further terminal at least takes over the display of the data for the operator. Calculation steps to obtain this display of the data from the obtained measurement results could theoretically be taken over by the terminal, for example using a suitable app.

The FIGS. 3 and 4 illustrate the detection of the asphalt layer and the determination of the position of the road roller 1 across the road using a thermal imaging camera as a temperature sensor 8. In particular illustrate the FIGS. 3 and 4 the influence of the perspective of the temperature sensor 8 on the measurement and how can be concluded from this measurement on the course and the position of the asphalt layer 11 and thus also on the position of the road roller 1 on the asphalt layer 11 across the road. FIG. 3 shows a side view, similar to the views FIGS. 1 and 2 , Out FIG. 3 it is clear that the measuring range of the temperature sensor 8 has a sensor depth 15 in the working direction a or parallel to the road. FIG. 4 shows a perspective view of the recorded by the temperature sensor 8 thermal image 13. The recorded by the temperature sensor 8 thermal image 13 has a sensor width 16 and a sensor depth 15, of which a total of the thermal image 13 is limited. The thermal image 13 is altogether composed of sensor segments 14, wherein each sensor segment 14 is, for example, a pixel of the resolution of the thermal imaging camera as a temperature sensor 8. In the exemplary embodiment shown, the thermal image 13 consists of 16 × 4 pixels.

Like also out FIG. 4 As can be seen, the thermal image 13 of the temperature sensor 8 is distorted perspective or trapezoidal due to its sensor perspective depending on the mounting location of the temperature sensor 8 on the road roller 1 and the measuring angle. This distortion must be taken into account in order to determine the actual course of the asphalt layer 11 to be compacted in FIG. 4 is shown as a comparison to the perspective thermal image 13 in plan view, to calculate from the measurement data of the temperature sensor 8. In particular, in FIG. 4 the asphalt layer 11 having a road width 17 and a road section length 18 is shown. The asphalt layer 11 is divided into a plurality of width segments 12, in the embodiment shown in thirteen approximately 1 m wide width segments 12, respectively. The position of the width segments 12 becomes defined by their distance either to the left edge 26 or the right edge 27 of the asphalt layer 11. As the course of the asphalt layer 11 is determined from the thermal image 13 of the temperature sensor 8, in particular from the superposition of the asphalt layer 11 with the thermal image 13 from FIG. 4 out. All sensor segments 14 of the thermal image 13, which image a part of the asphalt layer 11 and thus measure its temperature, show a significantly higher temperature than those sensor segments 14 of the thermal image 13, which image the lying next to the asphalt layer 11, much colder soil. In particular, by these transitions from the warm or hot asphalt layer 11 to the cold bottom of the left edge 26 and the right edge 27 of the asphalt layer 11 is determined. Once the edges 26, 27 have been determined, the width segments 12 can be defined by their respective distance from the edges 26, 27. Like also out FIG. 4 As can be seen from the thermal image 13 of the temperature sensor 8, as soon as the edges 26, 27 of the asphalt layer 11 are known, it can be determined on which width segments 12 or on which width segment 12 the road roller 1 is currently located. In FIG. 4 are those width segments 12 on which the road roller 1 must be due to the illustrated thermal image 13, designated 28. In this way it is possible to statistically detect in which width segments 12 the road roller 1 has done what proportion of its work.

The aim of the present invention is to provide the operator of the road roller 1 with an aid to obtain a statistical overview of the distribution of his work across the asphalt layer across the road. This guidance does not have to be particularly exact, so simplifications and approximations are applicable. Thus, for example, a slip occurring on the roller bandages 5 or wheels 6 can be statistically neglected overall. It can also be simplified assuming that the installation width of the paver does not change by and large. Despite these assumptions, the operator of the road roller 1 is informed by the present invention with sufficient accuracy about the distribution of the compression on the individual width segments. The operator is thus significantly relieved and can concentrate more on the actual control of the road roller 1, instead of having to spend too much effort on strict compliance with the rolling schedule. The present invention can also be used in the use of several road rollers 1. Driving the road rollers 1 in a row, the invention can be easily used individually in each road roller 1, without changing anything to the previously described circumstances. If the road rollers 1 side by side, so the system can be used easily without change, the corresponding of the respective road roller 1 not edited width segments 12 are then displayed as not edited. Alternatively, the measured data of the rollers involved in the compaction process are interchanged so that an overall distribution of the compaction work performed and the proportion of the respective roller are represented. Another possibility is that the operator limits the width of the asphalt layer 11 to be processed via an input possibility so that the width of the asphalt layer 11 is only up to a certain value of the distance of either the left edge 26 or the right edge 27 in the statistical Evaluation is recorded and displayed.

In FIG. 5 is shown for a more detailed explanation of the course of a compression process. The asphalt layer 11 to be compacted extends between the top and bottom dotted lines. The position of the road roller 1 is indicated by the circles marked with Roman numerals, on each of which the rolling width of the road roller 1 and thus the rolling track is indicated. The roller moves from position I to position II, from position III to position XIV, reversing at positions V and X. As indicated by the double arrows between positions I and II, the road roller 1 travels here with two roll bandages 5 flush behind each other, so that the entire width of the roller width of the road roller 1 substantially corresponds to the width of one of the roll bandages 5. From position XII, the road roller 1 then switches to the crab, so that the rolling width of the road roller 1, as indicated by the dashed lines widened. The crabbing is also shown between the positions XIII and XIV by the roll bandages 5, offset parallel to one another outwards, indicated by the double arrows.

As indicated by the dotted lines in FIG. 5 indicated, the asphalt layer 11 has been divided into five width segments 12 transverse to the longitudinal direction. About the temperature sensor 8, the position of the road roller 1 is now determined transversely to the longitudinal direction of the asphalt layer 11. The performance of the road roller 1 is then quantified as described above. For example, the distance covered is determined by means of odometry or the number of oscillations of a roller bandage 5 triggered by a vibration exciter, so-called compression strokes, are counted. The correspondingly determined work output is then assigned to this width segment 12 on the basis of the position of the road roller 1 on one of the width segments 12. For this purpose, in a simple embodiment, for example, the center of the road roller 1, in FIG. 5 indicated by the circles at the respective positions, are used. In the exemplary embodiment shown, the waypoints I-III would be assigned to the upper latitude segment 12, the waypoints IV and V to the second latitude segment 12 from above, the third latitude segment 12 from above to the waypoints VI-X and the fourth latitude segment from above to the waypoints XI-XIV. For the lowest latitude segment 12 no work would be registered. In order to increase the accuracy of the rolling width of the road roller 1 can be used in the statistical evaluation. For example, on the basis of the known rolling width of the road roller 1 and its position, it can be determined which portion of which roller bandage 5 is compacting the asphalt layer 11 on each width segment 12. The corresponding components can then be assigned to the respective width segments 12. In such a system, the crab position with an overall wider roller width of the road roller 1 can also be taken into account. The set roller width of the road roller 1 could be stored, for example, to each waypoint. In addition, the respective position of each roller bandage 5 of the road roller 1 could be logged or stored. By taking into account the actual roll width and its overlapping on the individual width segments 12, the accuracy of the method according to the invention can be greatly increased. As already explained, only the position of the road roller and the other parameters, such as the current rolling width, can be determined so that the division of the asphalt layer 11 into width segments 12 takes place only during the statistical evaluation of the data.

The FIGS. 6 and 7 Illustrate, by way of example, various displays 29, which present the registered data and its statistical evaluation to the operator of the road roller 1 in order to give him assistance in working operation. The displays 29 are designed here as bar graphs, for example. Each bar 31 represents a width segment 12 of the asphalt layer 11. In FIG. 6 For example, the asphalt layer 11 has been divided into three width segments 12, wherein the central width segment 12 is wider than the lying at the edge of the asphalt layer 11 width segments 12. This is in the display 29 of FIG. 6 indicated by differently wide bars 31, wherein the width of the beam 31 is proportional to the width of the width segments 12. The height of the bars 31 represents the quantified operating mode which has been registered and evaluated for the respective width segment 12. In the illustrated embodiment of the FIG. 6 So was the middle width segment 12 more compacted or on this segment was a higher compaction performance of the road roller 1 than on the two lying on the edge of the asphalt layer 11 width segments 12. In the embodiment shown with different widths bar 31, the workload on the of the width of the Bar 31 each represented area of the asphalt layer 11 converted, so that here again equal bars 31 represent a uniform compression. Of course, it is also possible to choose the width segments 12 each equal width. In addition to the bars 31, a position indication 30 is likewise provided in the display 29, which indicates the current position of the road roller 1 or the roller bandage 5 indicates transverse to the road. The width of the position indicator 30 can also be used to indicate the current roll width of the road roller 1, so that widened, for example, the position indication 30 when the road roller 1 changes to the crab. In the display 29 according to FIG. 7 the asphalt layer 11 was divided into five equally wide width segments 12. As already described above, a position indication 30 indicates the current position of the road roller 1 across the asphalt layer 11. Im in FIG. 7 In the embodiment shown, two road rollers 1 are in use in order to compact the asphalt layer 11 together. Both road rollers 1 perform the method according to the invention and are connected to each other via a radio link. In particular, the statistical evaluations of the two road rollers 1 are interchanged. In this way, it is possible for the operator of the road roller 1, as in FIG. 7 shown with the dashed bars 31, and the statistical evaluation of the working operation of the other road roller 1 is displayed. In this way, the operator of the road roller 1 always has a complete overview of how the compaction of the entire asphalt layer 11 progresses, even if he himself only processes a part of this asphalt layer 11. If necessary, each bar 31 may represent additional information such as temperatures or the like by colors or faded in numbers.

The FIG. 8 1 shows a flow chart of the method 19 according to the invention. The method 19 begins in step 20 with the detection of the edges 26, 27 bordering the hot asphalt layer 11 by means of the temperature sensor 8. The step 21 then divides the detected asphalt layer 11 into at least two Broad segments 12 across the street. In step 22, the position of the road roller 1 on the asphalt layer 11 across the road from the measurement of the temperature sensor 8 is determined and assigned to one of the width segments 12. The working operation of the road roller 1 on the respective width segment 12 is quantified in step 23 by an operating parameter as described above and stored in step 24, for example in a rolling storage system of the control unit 9. In step 25 the operator of the road roller 1 for a past working interval quantified work operation is displayed for each latitude segment 12. Like also in Figur5 shown, these steps 20-25 run continuously in succession, so that the operator of the road roller 1 is always a current statistical evaluation of the past working interval is displayed. In this way, the operator can not only retroactively adjust his operation, but also already do so, as soon as he determines that an uneven processing of the asphalt layer 11 could result if he simply continues to work without adjustment. All in all Thus, the quality of the road support layer can be improved, which increases their service life. At the same time, the operator of the road roller 1 is relieved in a simple and cost-effective manner.

Claims (12)

1. A method (19) for monitoring the compaction process of an asphalt layer (11) to be compacted in road construction, comprising the steps:

   a) detecting (20) the edges (26, 27) limiting the hot asphalt layer (11) transversely to the road pathway by means of a temperature sensor (8) arranged on a road roller (1) compacting the asphalt layer (11); and

   b) dividing (21) the detected asphalt layer (11) into at least two width segments (12) across the road pathway; in which

   d) the working operation of the road roller (1) on the width segment (12) is quantified (23) by means of an operating parameter and stored (24); and

   e) the quantified working operation for each width segment (12) is displayed (25) for at least one past working interval.

   characterized in that
   the position of the road roller (1) on the asphalt layer (11) transversely to the road pathway is determined from the measurement of the temperature sensor (8) and assigned (22) to one of the width segments (12);
2. The method (19) according to claim 1,
   characterized in that
   the detecting (20) of the edges (26, 27) limiting the hot asphalt layer (11) transversely to the road pathway occurs periodically and successively by means of the temperature sensor (8), or in that the temperature sensor (8) detects both edges (26, 27) simultaneously.
3. The method (19) according to one of the preceding claims,
   characterized in that
   at least one of the following parameters is used as the operating parameter:

   - a time period;

   - a number of passages;

   - a number of reversing operations;

   - a traveled distance;

   - a substrate stiffness; and/or

   - a vibration intensity of a roller drum (5) of the road roller (1).
4. The method (19) according to one of the preceding claims,
   characterized in that
   boundaries of the past working interval are defined using the same operating parameter as the one used for the quantification of the working operation and/or another parameter.
5. The method (19) according to one of the preceding claims,
   characterized in that
   the parameter or parameters used for the quantification of the working operation is/are stored during the working interval, wherein the data antecedent to the working interval are replaced by newly recorded data during the working operation.
6. The method (19) according to one of the preceding claims,
   characterized in that,
   the detected asphalt layer (11) is divided into at least the three width segments (12) "left side", "middle" and "right side" across the road pathway.
7. The method (19) according to one of the preceding claims,
   characterized in that
   the width segments (12) across the road pathway are equal in size.
8. The method (19) according to claim 6,
   characterized in that
   the width segments (12) located at the edges of the detected asphalt layer (11) have a smaller width across the road pathway than the width segments (12) located in the middle of the detected asphalt layer (11).
9. The method (19) according to one of the preceding claims,
   characterized in that,
   when determining the position of the road roller (1) on the asphalt layer (11) from the measurement of the temperature sensor (8), a measuring angle of the temperature sensor (8) and/or a traveling direction and/or a steering angle and/or a steering mode, e.g. a crab-steering mode, of the road roller (1) is/are taken into account.
10. A road roller (1), in particular a tandem roller, a single-drum roller or a rubber-tired roller, for compacting an asphalt layer (11) in road construction, with

    - a machine frame (3);

    - a drive engine (4);

    - a driver's cab (2);

    - at least one roller drum (5) and/or a wheel (6);

    - a temperature sensor (8); and

    - a control unit (9);

    characterized in that
    the control unit (9) is configured to carry out the method (19) according to one of the preceding claims.
11. The road roller (1) according to claim 10,
    characterized in that
    the control unit (9) comprises a rolling memory which stores the quantified working operation for each width segment (12) within the past working interval.
12. The road roller (1) according to one of claims 10 to 11,
    characterized in that
    the temperature sensor (8) comprises a thermal imaging camera.

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