DE202018006746U1 - Sensor system for a road finisher - Google Patents

Abstract

Road finisher (50) with a screed with an extendable part and a sensor system (1), with the following features:
a laser scanner (10), which is arranged on the extendable part of a screed (50b) of the road finisher (50) and is designed to search a predetermined angular range for one or more objects and corresponding distance values that indicate the distance to the one or more Describe objects, together with corresponding intensity values, which describe an intensity of a reflection occurring at the one or more objects, to be determined via angles of the specified angle range,
an evaluation unit (20) which is designed to recognize an object as a reference (54, 54s, 54k) together with an associated angle based on a known pattern, comprising the distance values and the intensity values over the scanning angle, and which is designed determine a distance to the reference (54, 54s, 54k) and the angle from the reference (54, 54s, 54k); and
a controller that is designed to move the extendable part or parts of the screed (50b) and/or the screed (50b) based on the distance to the reference (54, 54s, 54k) and the angle relative to the reference (54, 54s , 54k).

Description

Embodiments of the present invention relate to a sensor system for a construction machine, in particular for a road finisher. Further exemplary embodiments relate to a construction machine or in particular a road finisher with a corresponding sensor system. Additional embodiments relate to a method for determining a distance to a reference and/or an angle relative to the reference. Additional embodiments relate to a computer program. Preferred exemplary embodiments relate to a steering sensor for a road finisher and a height sensor for leveling a screed for a road finisher.

If you look at the main tasks of the road finisher in practice, then in addition to the high-precision leveling of the screed, precise steering is also necessary. Today, this is usually carried out manually by the paver operator. In order to pave as precisely as possible, the paver driver must carry out the steering corrections according to a specified reference in such a way that the paver runs as parallel as possible and at the same distance from this reference. Incorrect steering as well as influencing disturbances require a steering correction on the screed, which is carried out by the screed personnel via the control of the extendable part of the screed. Only the continuous and precise adjustment of the steering of the paver's tractor part and the tracking of the extendable screed part guarantee the correct course of the road, which is specified by the reference.

Automating the entire steering process (tractor and screed) could significantly relieve the paver operator during asphalt paving. This automation task requires a sensor, referred to below as a steering sensor, which is able to adapt to the different reference types, track them and determine the distance from the reference with great precision. Therefore, there is a need for an improved approach.

The object of the present invention is to create a sensor concept that creates an improved compromise between accuracy, adaptability for different conditions of use and ergonomics.

The object is solved by the independent patent claims.

Exemplary embodiments of the present invention create a sensor system for a construction machine, in particular for a road finisher, with at least one (first) laser scanner and an evaluation unit. The first laser scanner is arranged, for example, on the side of the construction machine/the road finisher itself. The laser scanner is designed to scan a predetermined angular range (e.g. semicircle or 180 degree arc or full circle or 360 degree arc or other angular range) for one or more objects (such as e.g. a rope, a marking or a milling or curb edge or the like) and corresponding distance values that describe the distance to the one or more (found) objects, together with corresponding intensity values that represent an intensity of a reflection occurring at the one or more objects describe, to determine. This determination takes place over the specified angle range, specifically with assignment of the distance values or intensity values to a respective angle within the specified angle range. The evaluation unit is designed to recognize an object as a reference together with the associated angles based on a known pattern consisting of or comprising the distance values and the intensity values over the angles. Here, for example, based on a specific pattern (combination of the variation of the intensity values together with the variation of the distance values across the angles), the curb or the rope is recognized or even differentiated from one another so that it can serve as a reference. Furthermore, the evaluation unit is designed to determine a distance from the reference and/or an angle with respect to the reference. In this case, for example, the distance between the first laser scanner and the reference is determined and/or an angle of a reference position (eg a horizontal line) with respect to the determined reference.

Embodiments of the present invention are based on the knowledge that laser scanners, extended by a corresponding evaluation, are suitable for measuring data patterns from different references that are required for steering or for height control/leveling of a screed of a road finisher or generally control of a road finisher are relevant to detect and differentiate. The evaluation unit also evaluates the measured values associated with the recorded reference (continuously, in particular along the route of the construction machine) or tracks them in order to determine a (transverse) position of the road finisher in relation to the reference (e.g. distance or angle). . According to a first application scenario, it is advantageously possible to use the sensor system described to control the steering of the road finisher very precisely, for example when paving asphalt. The corresponding distance values are included in this forwarded to the steering system, for example. Based on the position information, the steering corrections or generally the steering task of the road finisher or generally the control task of the road finisher can be taken over automatically in an optional manner. This corresponds to a control circuit for the steering, which largely relieves the operating personnel of the steering task.

According to one embodiment, the laser scanner can alternatively or additionally be arranged on an extendable part of a screed of the road finisher (or generally on a displaceable tool of the construction machine) in order to determine the (transverse) alignment of the component with respect to the reference. This results, for example, in the following application scenario: In addition to or instead of the steering task, the sensor system can advantageously also be used to regulate the screed width: laser sensor(s) arranged on the extendable parts of the screed are used, for example, to track the extendable parts of the screed to a reference. The task of the (alternative or second) control circuit constructed in this way for controlling the extendable parts is therefore to keep the distance to the reference constant by moving the extendable screed parts accordingly in order to enable small corrections to the width/transverse position of the covering to be applied.

According to one embodiment, the laser scanner can alternatively or additionally be arranged on the towing arm or in the vicinity of the towing point and/or on the screed, for example on a side plate of the screed or on an extendable part of the screed of the road finisher, and used as a height sensor , to provide height information as an alternative or in addition to the steering information. Advantageously, the sensor system can also be used to regulate the height or level the screed. If the laser scanner is attached close to the towing point, it is also suitable, for example, for height scanning on a reference rope. The sensor position of the laser scanner when used as a height sensor may have a different (mounting) position than when used as a steering sensor, e.g. near the towing point of the construction machine, while the sensors used for steering purposes can be attached to the corners.

As already indicated above, the evaluation unit is designed to recognize different types of objects as a reference based on different known patterns. For example, according to exemplary embodiments, the evaluation unit can be connected to a user interface, via which a user has the option of making a user selection with regard to the type of object to be recognized. In response to this, the evaluation unit then searches for the corresponding type of object to be recognized, e.g. B. a corresponding milled edge or a corresponding rope to be used as a reference.

According to exemplary embodiments, the object to be recognized is a rope. The evaluation unit recognizes a rope, for example, when a maximum of the intensity values is present in the form of a (narrow) peak and when at the same time a minimum of the distance values is also present in the form of a (narrow) peak. For example, a (narrow) peak has a width of 2° to 4° or 1° to 7.50° (generally in the range 0.1° to 10° or 15°). Alternatively, the evaluation unit can also detect a rope when a peak-shaped change (maximum) in the intensity values and a peak-shaped change (minimum) in the distance values are detected at the same angle in the specified measurement range. When using a rope as a reference, according to exemplary embodiments, a distinction must be made between two modes (detection in a bird's-eye view from above or detection in a lateral perspective). According to one embodiment, the evaluation unit recognizes a rope from a bird's-eye view, e.g. B. based on the pattern explained above and determines an angle α in the predetermined angular range, z. B. opposite a solder on the ground of the laser scanner. Based on the measured/determined angle α, the evaluation unit can also calculate a distance a using the formula a=tan α·h (height h of the laser scanner relative to the cable). According to further exemplary embodiments, the evaluation unit is designed to recognize a rope from a lateral perspective and to determine a distance from the rope purely by means of the laser measurement.

According to further exemplary embodiments, the evaluation unit is designed in addition or as an alternative to an edge, such as, for. B. to recognize a milled edge or a curb. This edge can be recognized in two different modes, namely in a side view and in a bird's eye view. For example, the evaluation unit detects an edge in a lateral perspective if the intensity values form an elevation in an angular range of the specified angular range or if the distance values form a plateau of the distance values in an angular range of the specified angular range. Alternatively, the evaluation unit recognizes a combination of the plateau of the distance values and an increase in the intensity values as an edge, in particular when the plateau and the superelevation are in a common angular range of the specified angular range appear richly. According to further exemplary embodiments, the evaluation unit recognizes an edge in the bird's-eye view when the distance values form a jump at an angle of the specified angular range or when the distance values form a (continuous) maximum at an angle of the specified angular range. The evaluation unit preferably recognizes an edge when the distance values form a jump in an angle of the predetermined angular range and the distance values simultaneously form a maximum at this angle. In accordance with further exemplary embodiments, analogously to the detection of the rope, it is possible for a (lateral) distance a to be determined based on the (measured) angle at which the edge was detected, the formula a=tan α*height h.

According to a further exemplary embodiment, the evaluation unit is designed to measure a line, e.g. B. to recognize in the side perspective on a wall or in a bird's eye view on the ground. According to exemplary embodiments, the evaluation unit then recognizes a line when a maximum of the intensity values in the form of a peak in combination with a continuously/steadily varying distance value or even a minimum of the continuously varying distance value at an angle is obtained. If the distance is determined from the side, the distance value determined by the laser is used as the reference value for the controller, while if the line is recognized from above, the distance is determined by offsetting the angle.

wobei I_i der Abstandswert der jeweiligen Messung ist, i die Anzahl der Messungen, n die Anzahl der aufeinanderfolgenden annähernden gleichen Messungen und L der mittlere Abstandswert zur Referenz.According to exemplary embodiments, the evaluation unit reads the distance values continuously, e.g. B. while driving, ie over a certain period of time or over a distance traveled. In this case, for example, n distance values are then obtained, which should be essentially the same due to the fact that the distance covered is very small at the low speed that is typically driven. Therefore, these final distance values can be averaged with the following formula: $$\overline{Abstan\mathrm{i.e}}=L=\frac{{\displaystyle {\sum }_{i=0}^{n}li}}{n}$$

where I _i is the distance value of the respective measurement, i the number of measurements, n the number of consecutive approximately equal measurements and L the average distance value to the reference.

As already explained above, the laser sensor can be arranged on an extendable part of the screed or on a road finisher itself. According to one embodiment, the sensor system therefore comprises at least two laser sensors, one arranged on the construction machine / paver (for steering or leveling purposes) and one or even two arranged on the (both) extendable parts of the screed (for controlling the screed width) or for height control /Leveling the screed. The sensors are preferably arranged laterally (laterally in front and laterally behind) on the side of the reference. In this case, the front side of the road finisher (opposite the screed, for example in the front area of the travel drive) is preferably selected as far forward as possible, or the rear side, namely as far back as possible. According to a further exemplary embodiment, the two laser sensors can of course also be arranged on only one side, if one assumes, for example, that only one reference is present on only one side. According to a further embodiment, the sensor system comprises at least four laser scanners, namely two on the extendable parts for controlling the screed width and two on the road finisher for steering the road finisher itself (e.g. in the front area of the travel drive) or also for height control/leveling of the screed, assuming, for example, two lateral references.

According to exemplary embodiments, the sensor system includes a controller that is designed to control the extendable parts of the screed or the screed. This control can take place taking into account a fixed machine point, assuming that the laser scanner(s) is/are arranged on the extendable part or on the screed, but with a certain offset to the surfaces to be controlled. According to further exemplary embodiments, the sensor system includes a controller for controlling the steering of the road finisher. Here, the control structure, taking into account a machine fixed point, z. B. to the pivot point of the paver.

A further exemplary embodiment relates to the fact that the laser scanner, in addition to evaluating an edge or determining the distance from a reference wire, can also generate height information for leveling a screed of a road finisher if the screed is leveled using a reference wire. In this case, scanning preferably takes place to the side of the reference wire. Preferably, the sensor is mounted on the tow arm near the tow point, e.g. H. seen in the direction of travel of the road finisher in the front area of the towing arm, and in this position offers possibilities for an optimized leveling of the screed of a road finisher.

According to exemplary embodiments, the controller is designed to regulate or level the height of the screed.

• - Erkennen eines Objekts als Referenz zusammen mit dem zugehörigen Winkel ausgehend von einem bekannten Muster, umfasst die Abstände und die Intensitätswerte über die Winkel des vorgegebenen Winkelbereichs;
• - Bestimmen eines Abstands zu der Referenz und/oder eines Winkels gegenüber der Referenz (aus welchem dann im Endeffekt der Abstand bestimmbar ist).

A further exemplary embodiment relates to a method for determining a distance from a reference and/or an angle with respect to the reference using at least one first laser scanner, as explained above. The procedure includes the steps:

• - Recognizing an object as a reference together with the associated angle based on a known pattern, includes the distances and the intensity values over the angles of the predetermined angle range;
• - Determining a distance to the reference and/or an angle relative to the reference (from which the distance can ultimately be determined).

According to further exemplary embodiments, this method can also be computer-implemented.

• 1a eine schematische Darstellung eines Sensorsystems gemäß einem Basisausführungsbeispiel;
• 1 b eine schematische Darstellung von möglichen Anbringungsorten der Sensoren des Sensorsystems an einem Straßenfertiger gemäß weiteren Ausführungsbeispielen;
• 1c bis 1d schematische Darstellungen zur Illustration der mittels des Sensorsystems zu messenden Messgrößen im Verhältnis zu den Regelungsgrößen;
• 2a bis 2d schematische Darstellungen eines Straßenfertigers mit unterschiedlich angeordneten Laserscannern zur Erläuterung der unterschiedlich anzupeilenden Referenzen gemäß Ausführungsbeispielen;
• 3a bis 3e schematische Darstellung zur Erläuterung der Mustererkennung „Seil“ gemäß Ausführungsbeispielen;
• 4a bis 4f schematische Darstellungen zur Erläuterung der Mustererkennung „Fräskante“ gemäß Ausführungsbeispielen;
• 5a bis 5b schematische Darstellungen zur Erläuterung der Mustererkennung „Linie“ gemäß Ausführungsbeispielen;
• 6a bis 6b schematische Darstellungen von Funktionsblöcken einer Auswerteeinheit gemäß Ausführungsbeispielen;
• 6c eine schematische Darstellung eines Scanbereichs eines Laserscanners;
• 7a eine schematische Darstellung des Laserscanners zur Verwendung als Höhensensor gemäß Ausführungsbeispielen;
• 7b eine schematische Darstellung zur Erläuterung der Umrechnung einer Winkelinformation in eine Höheninformation gemäß Ausführungsbeispielen; und
• 7c eine schematische Darstellung zur Erläuterung einer Messung der Anzahl der Laserpulse, bis ein Referenzdraht getroffen wird.

Another embodiment provides a road finisher and a corresponding sensor system. Further developments are defined in the dependent claims. Exemplary embodiments of the present invention are explained with reference to the accompanying drawings. Show it:

• 1a a schematic representation of a sensor system according to a basic embodiment;
• 1 b a schematic representation of possible mounting locations of the sensors of the sensor system on a road finisher according to further exemplary embodiments;
• 1c until 1d schematic representations to illustrate the measured variables to be measured by the sensor system in relation to the control variables;
• 2a until 2d schematic representations of a road finisher with differently arranged laser scanners to explain the different references to be aimed for according to exemplary embodiments;
• 3a until 3e schematic representation to explain the pattern recognition “rope” according to exemplary embodiments;
• 4a until 4f schematic representations to explain the pattern recognition “milling edge” according to exemplary embodiments;
• 5a until 5b schematic representations to explain the pattern recognition “line” according to exemplary embodiments;
• 6a until 6b schematic representations of functional blocks of an evaluation unit according to exemplary embodiments;
• 6c a schematic representation of a scanning area of a laser scanner;
• 7a a schematic representation of the laser scanner for use as a height sensor according to embodiments;
• 7b a schematic representation to explain the conversion of angle information into height information according to exemplary embodiments; and
• 7c a schematic representation to explain a measurement of the number of laser pulses until a reference wire is hit.

Before exemplary embodiments of the present invention are explained below with reference to the attached drawings, it should be noted that suitable elements and structures are provided with the same reference symbols, so that the description can be applied to one another or are interchangeable.

1a shows a schematic representation of a sensor system 1 with a laser module as the first laser scanner 10 and an evaluation unit 20, the z. B. is connected to the laser scanner 10 via a cable.

The laser scanner 10 serves as a sensor element and scans z. B. in a laser level 11, the measuring range for objects such. B. a rope or a curb or other element that can serve as a reference. The laser plane 11 forms a fan of possible scanning angles (60-degree fan, 135-degree fan or 180-degree fan or fan with any angle/angle range) spanned by a laser beam, which forms the unrestricted measuring range. For example, the fan is stretched perpendicular to the direction of travel, whereby perpendicular can mean that a zero angle protrudes vertically downwards and further angles can be scanned to the left and right with +/- x°, e.g. +/-90° (in this area there is a Scanning possible, so that can be referred to as a range comprising scanning angle). For example, a rotating laser beam (red light or light in the IR range) is emitted along the fan and the reflection characteristics are received by a receiver integrated in the scanner. Such scanners have a scan rate of 50Hz, for example, in order to ensure the time and angular resolution. The range of such scanners can be seen in the range from a few millimeters (1mm) to 100m. The use of a laser 10 as a sensor offers the advantage that this works without contact and can not only detect objects, but also the distance between the object and the laser scanner and/or the angle of the object to a reference position (e.g. a horizontal or vertical line, which can and may also vary depending on the alignment of the laser scanner is corrected for an offset resulting from an angled alignment / misalignment of the laser scanner) is determined with high precision. Furthermore, this sensor also enables the continuous tracking of the reference. Tracking means that over time the distance to the same and/or the angle relative to the same is determined/tracked based on a known (position/orientation of the scanner). The evaluation unit 20 detects, tracks and evaluates the reference.

The evaluation unit 20 can be implemented by a CPU, for example, and is designed to process the measured values supplied by the laser module 10 in such a way that at the end of the calculation chain the highly precise distance from the steering or height reference is available as a measurement result. The result is then made available, for example, to a higher-level steering control system and/or a leveling control system.

The steering sensor 1 or the sensor system 1 shown here can be used universally, namely both for tractor steering (steering the traction drive) and for screed control (lateral position and/or height). How referring to 1b is shown, the universally usable steering sensor 1 (sensor system 1) or the laser module 10 can be arranged at several different lateral positions of the road finisher, depending on whether the sensor system 1 is used as a steering and/or as a height sensor.

1b shows a road finisher 50 with a screed 50b, which is laterally delimited by the extendable screed arms 50a. Depending on the extended state of the extendable parts 50a, the width of the screed 50b changes and thus also the width of the asphalt layer 52 to be installed. B. in the installation area 52e or to adjust the plank width and / or to carry out a height leveling of the plank 50b, reference is made to a reference 54, z. B. taken a stretched next to the installation area 52e rope. This reference can be obtained using the in 1a explained laser sensors are detected.

According to a first variant would be an installation position on the road finisher 50, z. B. at the front 50v conceivable. A steering sensor 10v is shown purely as an example. This is provided here at a maximum distance from the pivot point 50d of the road finisher. The steering of the road finisher can be supported or automated by means of this attachment point 10v, as will be explained below. The steering of the paver 50 is generally aimed at controlling the forward movement of the machine 50 in parallel along the reference 54 when paving asphalt. In this case, the tractor from the road finisher 50 initially takes over the actual steering of the machine 50. Corresponding steering systems are available for this purpose, which are usually operated manually.

If the distance between the sensor 10v and the reference 54 changes, this can be due to a steering correction (rotation about the steering pivot point 50d) so that the directional vector of the machine changes. This change can be detected by the sensor 10v. If you move the paver at the time of the steering correction (cf. 1d ) considered, it can be seen that at the height of the pivot point 50d the distance a has changed compared to the point in time before the steering correction (cf. 1c ) has hardly changed, while the distance b changes much more. As a result, this measure results in a corresponding signal change for the steering sensor 10v or also all steering sensors arranged far in front or far behind at the time of the steering correction. It is therefore advantageous, but not mandatory, for the attachment locations of the steering sensors 10v for the tractor or in general (i.e. also for the further exemplary embodiment “attachment location Bohle”) to be selected such that they are as far away as possible from the steering pivot point 50d.

According to a further exemplary embodiment, the steering sensor can also be arranged on the screed 50b or in particular on the extendable part of the screed 50a. This makes it possible in particular to guide the side panels of the extensible parts 50a with respect to the reference 54. The mounting location 10h for the steering sensor on the extendable part 50a is shown here as an example. While the steering sensor 10v serves to automate the steering of the tractor 50d, the steering control circuit for the screed can be automated by means of the steering sensor 10h. Minor steering inaccuracies can be corrected via the screed 50b or the extendable parts 50a of the screed 50b. According to preferred embodiments, the rear-mounted steering sensors 10h form a control loop with the screed, while the front-mounted sensors 10v provide a steering control loop for the tractor. In this respect, each sensor 10v and 10h has its own control circuit, which keeps the distance from the specified reference 54 constant. In particular, minor steering inaccuracies and other disturbances, which do not result in the desired paving can be corrected by the operating personnel at the control stand or automatically via the extendable part 50a of the screed 50b.

The attachment of the steering sensors to the tractor part and to the screed, as well as the different reference types that are used in parallel, requires various evaluation mechanisms which, in addition to identifying the reference, also determine the distance to the reference. This is explained in detail below.

According to an optional/alternative variant, the sensor 10z can also be attached in the area of the towing arm. Furthermore, another possible attachment location for the sensor on the rear edge of the screed is marked with the reference number 10bh. This mounting location represents a preferred variant for the height control.

• Der Lenksensor 10v vom Traktor 50 soll, wie Bezug nehmend auf 1c und 1d erläutert ist, möglichst weit im Vorhalt angebracht sein, damit durch eine Lenkkorrektur vom Fertiger, die Abstandsänderung zur Referenz 54k (hier eine Fräskante) signifikant ändert. Hierdurch wird eine wesentlich bessere Feinjustierung der Lenkung erreicht. An dieser Stelle sei angemerkt, dass diese Positionierung bevorzugt, aber nicht zwingend ist. Ebenso ist die Positionierung des Sensors 10v an der Seite bevorzugt, wie hier in der Vorderansicht von 2a dargestellt ist. Hintergrund zur seitlichen Anordnung besteht darin, dass die Referenz, hier die Fräskante 54k im relevanten Scanbereich 10s von dem Laserscanner 10v angeordnet ist. Wie hier dargestellt, scannt der Laserscanner 10v einen beispielsweise im 30-Grad-Winkel aufgespannten Messbereich den Untergrund 52e, auf welchem die Asphaltschicht 52 aufgebracht werden soll, nach der Fräskante 54k ab. Hierbei ist dieser relevante Messbereich 10s bereits gegenüber der Horizontalen geneigt, z. B. um 15 Grad. Somit ergibt sich also ein exemplarischer Scanbereich von 15 bis 45 Grad bezogen auf die Horizontale. An dieser Stelle sei angemerkt, dass je nach Anbringungshöhe des Lenksensors 10v (gegenüber dem Untergrund 52e) und (lateraler) Abstand der Fräskante 54k dieser Messbereich variieren kann.

In 2a the "steering sensor" case for the tractor part of the finisher for scanning a milled edge is illustrated:

• The steering sensor 10v from the tractor 50 should, as referring to FIG 1c and 1d is explained, be attached as far ahead as possible, so that a steering correction from the paver significantly changes the distance change to the reference 54k (here a milled edge). As a result, a much better fine adjustment of the steering is achieved. At this point it should be noted that this positioning is preferred but not mandatory. Likewise, the positioning of the sensor 10v on the side is preferred, as here in the front view of FIG 2a is shown. The background to the lateral arrangement is that the reference, here the milling edge 54k, is arranged in the relevant scanning area 10s of the laser scanner 10v. As shown here, the laser scanner 10v scans a measurement area spanned, for example, at a 30-degree angle, the subsoil 52e, on which the asphalt layer 52 is to be applied, for the milled edge 54k. In this case, this relevant measuring range 10s is already inclined relative to the horizontal, e.g. B. by 15 degrees. This results in an exemplary scanning range of 15 to 45 degrees in relation to the horizontal. At this point it should be noted that this measuring range can vary depending on the mounting height of the steering sensor 10v (relative to the subsurface 52e) and (lateral) distance of the milling edge 54k.

2 B illustrates a further case, namely the arrangement of the steering sensor 10v for scanning a reference cable 54s, which in turn is arranged laterally on the finisher 50 shown in the front view. In this exemplary embodiment, the cable 54s is arranged by means of a cable holder 54sh at approximately the same height relative to the base 52e as the laser scanner 10v. In this exemplary embodiment, the laser scanner 10v does not scan the subsurface 52e, but rather the lateral area for the cable 54s. Starting from an identical position of the sensor 10v compared to the variant 2a in this non-angled variant, the distance between the laser scanner 10v and the cable 54s is determined directly by means of the laser, which in the variant is off 2a either the distance between the milled edge 54k and the laser scanner 10v, taking into account the angle or the height, or the angle at which the milled edge 54k is obtained, taking the height into account, is taken as the corresponding reference dimension.

2c shows the use of the laser scanner 10h on the screed to scan a milled edge 54k. Here, a laser scanner 10h is located on the rear part of the finisher 50. Since the screed 50b or in particular the extendable parts of the screed 50a are always positioned in the outer area of the asphalt layer 52a to be applied, the laser scanner 50h can be aligned vertically downwards, so that it captures the milling edge 54k in a bird's-eye view. For this purpose, laser scanner 50h is arranged, for example, on the side panel of extendable part 50a in such a way that the sensor can detect the milled edge from above, and preferably in such a way that it detects milled edge 54k at an angle of 0 degrees, i.e. vertically below laser scanner 54h, if the side panel of the extendable part 50h is correctly positioned. The deviation from this correct position, ie the angle at which the milled edge 54k is detected, can be made available as a measured value to the control loop for the extendable parts 50a of the screed 50b.

In 2d a laser scanner 10h arranged on the screed for scanning a reference cable 54s is shown. The reference cable 54s is in turn held by the holder 54sh, preferably at the height of the laser scanner 10h. This use of a cable 54s as a reference can take place as an alternative or in addition to the milling edge evaluation. Here, as already in connection with 2 B explained, the distance to the reference is measured, the measured value being made available to the control loop for the extendable part of the screed.

Proceeding from these positions, it is evident that, in accordance with preferred exemplary embodiments, a sensor system for the control loop of the extendable parts of the screed at least has a laser scanner (on the side of the laser scanner for steering control) or preferably two laser scanners (left, right), while a sensor system for steering the road finisher has one or two laser scanners. According to one implementation, the sensor system includes an evaluation unit and four laser scanners. Alternatively, each laser scanner can also be coupled directly to an evaluation unit. According to exemplary embodiments, this is directly integrated in the sensor.

According to a preferred implementation, the sensor system comprises a total of four laser scanners 10v and 10h, which are arranged on the left and right at the above-explained positions of the extendable parts 50a and finisher 50 themselves.

The laser scanner 10 or the sensor system 1 can alternatively or additionally be arranged on the towing arm 50z or in the vicinity of the towing point and/or on the screed 50b, for example on a side plate/side plate of the screed 50b or on an extendable part of the screed 50a of the Road finisher, and used or used as a height sensor to provide height information as an alternative or in addition to the steering information. Advantageously, the height of the screed 50b can also be regulated or leveled with the sensor system. If the laser scanner 10 is attached in the vicinity of the towing point, it is also suitable, for example, for height scanning on a reference rope 54s. In this case, the sensor position of the laser scanner 10 when used as a height sensor may have a different (mounting) position than when used as a steering sensor.

Scanning preferably takes place to the side of the reference wire/reference rope 54s. Preferably, the laser scanner 10 is mounted on the tow arm 50z near the tow point, i. H. seen in the direction of travel of the road finisher in the front area of the towing arm 50z, and at this position offers possibilities for an optimized leveling of the screed 50b of the road finisher 50.

The laser scanner 10 enables height scanning based on the angle information that is supplied with each scanning value. It is crucial that the laser scanner 10 has the highest possible angular resolution. In the example according to 7a An angular resolution of approximately 0.01° is assumed. The distance to the reference wire/reference rope 54s is usually between one and four meters.

In this case, a height resolution changes with the distance from the reference wire/reference cable 54s, ie increases with increasing distance from the reference wire/reference cable 54s. As in 7a shown, the height resolution Δh is calculated using the formula Δh = tan angle (angle resolution laser scanner) . Distance. For example, the (measured) angle in combination with the (measured) distance to the reference 54s is used to calculate Δh. With an angular resolution of the laser scanner 10 of approximately 0.01°, as specified above, and a distance of 4 m, a height resolution Δh of 0.70 mm results. In comparison, the height resolution Δh at a distance of 1 m is approx. 0.17 mm. Such height resolution values are quite sufficient for leveling the screed of a road finisher. In addition to a change in the height resolution at different distances from the reference wire/reference rope 54s, the number of hits from the reference wire/reference rope 54s by the laser beam also changes, which emits a laser pulse with each measurement and determines the distance over the duration of the pulse. This change in the number of hits must be taken into account for an altitude calculation and is considered in more detail below.

A measurement of the height by the laser scanner 10, which is preferably arranged on the towing arm 50z in the vicinity of the towing point, i.e. in the front area of the towing arm 50z as seen in the direction of travel of the road finisher 50, relative to the reference wire/reference rope 54s is therefore not only carried out via a distance measurement determined, but also via an angle measurement that is assigned to each laser pulse. In order to obtain height information or to determine a height which is related to the reference wire/reference rope 54s and thus also represents the relative height of the road finisher pull arm 50z to the reference wire/reference rope 54s, the angle measurement from the laser scanner 10 has a fixed reference point, whose position does not change. i.e. the angle information always relates to this fixed point in the laser scanner 10. Starting from this fixed reference point, the measuring system then counts n _m angular steps until the reference wire or the reference rope 54s is hit. Using the counted angular steps n _m (alternatively using the measured angle), the distance b to the rope 54s and the angle Δα, which represents the angle between two consecutive distance measurements, the relative height (h) can be determined using the formula h = tan (n _m * Δα) * b. 7b should make this clearer. The relative height (h) determined in this way can in turn be provided with an offset in such a way that the height value 0 mm is output by the measuring system in a calibrated state by the "finisher - reference wire" system.

mit:

• n_i = Anzahl der Lasermessungen, bei denen die Referenz nicht getroffen wurde; und
• n_r = Anzahl der Lasermessungen, bei denen die Referenz vollständig von Laserstrahlen getroffenen wurde.

If the reference wire is hit several times by the laser beam, n _m must be evaluated in such a way that the value of n _m reflects the center of the rope 54s. 7c should make this clear. The number of laser pulses until the reference wire 54s is hit is calculated as follows: $$n_m=n_i+\frac{n_{\mathrm{right}}}{2}$$

With:

• n _i = number of laser measurements where the reference was missed; and
• n _r = number of laser measurements in which the reference was completely hit by laser beams.

As an alternative to calculating the height in millimeters shown, you can also use the count value of the laser pulses n _m to specify the height information. The only difference to the height information in mm is that _nm is dimensionless and does not take into account the distance between the laser scanner and the reference wire.

According to a preferred embodiment, each laser scanner is suitable for e.g. B. starting from a user input after a certain reference, z. B. the milling edge 54k or the reference cable 54s and to detect this for distance measurement or to determine the distance continuously. The selection is made via user input or automatically depending on availability.

According to a further embodiment, another object, such as. For example, a line drawn on a wall can serve as a reference. Before the distance measurement is discussed in detail below, the laser scanner or an exemplary version of the laser scanner will be explained in advance.

• - Abstandswert zu dem erfassten Objekt
• - Signalstärke (Reflexionsgrad) und
• - Messwinkel (zu einer Bezugsachse 10bv oder 10bh)

The laser scanner 10, as for example in 1 or 6a is shown can be designed, for example, as a rotating laser scanner that carries out a continuous distance measurement, so that all contours in the plane of rotation of the laser can be measured using the measured distance vectors. In addition to the distance value, the measurement vector from the laser scanner also has information about the signal strength (degree of reflection of the measurement) and the measurement angle, which relates to an internal reference point). For this see the in 6c shown scanning area. As can be seen, the scanning area has two reference axes, namely a horizontal reference axis 10bh and a vertical reference axis 10bv. In the exemplary embodiment, all measurement angles a1, a2 and a3 are related to the X-axis 10bv, ie to the vertical line. If the laser scanner is permanently installed on the paver, the reference point also has a fixed relationship to the paver itself, e.g. B. a distance to the motion vector through the pivot point. Overall, this results in a measurement vector that consists of three information components per measurement process:

• - Distance value to the detected object
• - signal strength (reflectance) and
• - Measuring angle (to a reference axis 10bv or 10bh)

Depending on the height at which the sensor 10 is arranged, there is a measurement angle a1, a2 and a3 to the respective reference. Here, the reference angle a1 for scanning, z. B. a milling edge 54k from above, a2 for scanning a lateral reference 54s from the side and a3 for scanning a temporal milling edge 54k. The measuring angles a1, a2 and a3 represent the relation to the reference axis 10bv of the laser plane.

• - Fräskante
• - Gespanntes Referenzseil
• - Referenzlinien
• - Bordsteinkante

In the following, reference is made to 3a until 3e and FIGS. 4a to 4f explain the pattern recognition of the respective reference. In practice, the following possibilities arise for the steering reference or for the reference in general:

• - milling edge
• - Tensioned reference rope
• - Reference lines
• - Curb

Each steering reference or reference in general has a specific reference contour, which in turn produces specific signal curves when scanned, from which the identification of the reference can be derived. The signal curves must be analyzed in an evaluation algorithm in such a way that, in addition to the reference detection, the exact distance to the reference is also determined.

In 3a the pattern recognition of a rope 54s by means of the laser scanner 10 is shown. Here, the laser scanner 10 provides only a few measurements (3 to 5 measurements—depending on the distance and rope diameter) with a high signal amplitude and thus with a high degree of reflection. All other measured values are either further away and/or have a low signal amplitude.

for the inside 3a The scanning situation shown results in principle in 3ba illustrated signal course for distance measurement values 15a and signal strength 15s. These two measured values 15a and 15s are plotted over the measuring angle. As can be seen, form in the scan area 17, z. B. in the range between 88 and 92 degrees peak-shaped signal curves of the measured values 15a and 15s. These characteristics of a change (minimum) in measurement distance 15a occurring at the same angle with a change (maximum) in signal strength 15s at one angle enable detection of a rope. Starting from the measured value 15a at its minimum, the distance to the reference can be determined. In this respect, the evaluation algorithm has the task of determining the minimum distance to the reference for the situation of lateral rope detection at maximum signal strength, which then also reflects the measurement distance to the reference.

3bb illustrates an alternative signal course for distance measurements 15a and signal strength 15s. Here the scanning area 17 is delimited by minima 17b, between which the one maxima of the signal strength 15s is formed. When detecting the rope, the minimum values 17b can be used in addition to the maximum signal strength.

3c illustrates the scanning situation with a laser scanner 10 for detecting a cable 54s arranged under the laser scanner 10. In this case, the laser scanner is arranged, for example, on the side plate of the screed 50a. With such a measurement, the in 3d signal curve shown. As can be seen here, the minimum and maximum of the signal strength 15a and the measurement distance 15s again coincide in the scanning area 17, so that the position of the rope or the measurement angle for the rope can be detected here.

The evaluation of the reference rope 54s from above has measured values with high signal amplitudes for a relatively large scan angle (30° to 50°), with a measured value jump (measured values abruptly smaller) occurring directly above the reference rope. 3c shows the basic arrangement of the laser scanner 10 and scanning area 17, while 3d illustrates the associated signal curve. It should be noted here that the measurement distance to the rope is measured in the Y direction. However, a distance value in the X direction is required for the control. For this purpose, as in a conversion is shown.

In this respect, in this exemplary embodiment, not only the distance value resulting from the measured value 15a is used to determine the distance, but rather the distance is determined by means of the following calculation. The calculation is made below using 3e explained. 3e shows the diagram 3d , which shows that measured values 15a and 15s coincide under the position a = 0 degrees. The distance to the cable or the height h above the cable can be determined from the measured value 15a. In this respect, the laser scanner 10 is located perpendicularly above the cable 54s, as a result of which the zero reference, ie the measured value has the value a=0 at this point, is established in this exemplary embodiment. If the angle to the rope now changes, the distance a can be determined using the formula a = tan α · h, such as using 3e is illustrated. The distance value a determined in this way supplies the distance to the zero reference in the X direction.

While the zero reference is set in the laser scanner, the laser scanner must be installed during setup so that the distance value a is as close to zero as possible. The distance value determined in this way in the X direction can then be used as a controlled variable.

In this respect, the use of the rope as a lateral reference differs from the use of the rope as a reference when measuring from above, primarily in the calculation of the controlled variable, but not in the signal pattern that occurs when the object is detected.

4a illustrates the pattern recognition of a milled edge 54k by means of the laser scanner 10 from the side. For example, the laser scanner 10 again scans a scanning area of 15 to 45 degrees or of 15 to 30 degrees.

A milled edge 54k also supplies a special pattern, with the help of which the distance to the milled edge 54k can be clearly determined. This should in 4b be explained in such a way that the pattern of the milled edge can be recognized by consecutively following identical measured values with a relatively high signal amplitude. Looking at the in signal curves of the signal strength 15s and the measuring distance 15a shown, the special pattern recognition of the signal curves becomes clear. A corresponding recognition or evaluation algorithm recognizes the slight increase in the signal strength 15sp in the scanning area 17, which represents the measuring angle for the milling edge 54h. Additionally or alternatively, the evaluation algorithm can also recognize approximately the same distance values 15a in this scanning area 17 . In this respect, the pattern recognition of a milled edge from the side consists in recognizing a lateral elevation (cf. reference number 15s) as in the case of the signal strength and/or a plateau 15ap for the measured distance value 15a, with 15sp and 15ap being essentially in the same measuring range/angle range 17 appear. The plateau 15ap also represents the measuring distance to be evaluated from the milling edge.

Referring to 4c the pattern recognition of a milled edge 54k is explained from above. For this purpose, the laser scanner 10 is arranged above the milling edge 54k. The resulting waveform is in 4d shown. How based on 4d can be seen, when evaluating the milling edge 54k from above, a relatively large scanning angle (eg 30° to 50°) of measured values for the signal strength 15s and for the measuring distance 15a with a high signal amplitude results. With a signal strength of 15s, a measured value jump of 15ss from h1 to h2 is recorded at the position of the milled edge. This jump provides the exact position of the milled edge in relation to the measuring angle (here: a = 0 degrees). In addition to the distance values, the scan angle at which the height jump from h1 to h2 occurs is decisive. The distance measurement is used here only to detect the change in distance from h1 to h2. If you assume that the angle α = 0 degrees or any angle in the measuring range is taken as a reference value, it is not the distance but the scanning angle at which the height jump occurs that must be kept constant in this application. According to an alternative, the scan angle can also be converted into a distance value (lateral or vertical distance), as shown in 4e and 4f becomes evident. at 4e the situation is over 4c shown, but the scanner 10 is not arranged vertically above but laterally offset relative to the milling edge 54k. As a result, an angle α (angle of the jump) is set. Based on the formula a = tan(α) h with a equal to the distance and h equal to the height (cf. 4f) the lateral distance can be determined.

Both for the variant 4c as well as for the variant 4e the signal pattern is off for the distance calculation to the reference 4d relevant. If the laser scanner 10 is located perpendicularly above the milled edge 54s, the zero reference is established here, ie the measuring angle has the value a=0 degrees at this point. If the laser scanner 10 is not located vertically above the reference (here milling edge 54k offset to the top right), the measurement angle a changes in relation to the zero reference. The measurement distance to the reference can therefore be calculated like the tangent value, so that the distance value a determined in this way in the X direction (lateral) represents the distance to the zero reference. While the zero reference is fixed in the laser scanner, the laser scanner 10 should be installed during setup in such a way that the distance value a is as close to zero as possible.

In the following, reference is made to 5a a pattern recognition of a line 54I, e.g. B. explained on a tunnel wall 54t.

5a shows a laser scanner arranged on a screed or in the extendable part 50a of the screed 50b, the measuring range of which is aligned in such a way that it scans the tunnel wall 50t laterally. The reference line 54I attached to the tunnel wall 50t also provides a special pattern with the aid of which the distance between the reference line 54I and the laser scanner 10 can be determined unambiguously. The example described here relates to a light (e.g. white) reference line 541 on a dark background (e.g. a concrete wall 54t). For the sake of completeness, it should be pointed out that the pattern recognition described can also be used to recognize a dark line 541 (for example a black or gray line) on a light background 54t, with a representation of a signal profile then being essentially reversed.

5b shows the signal curve of the signal strength 15a and the measuring distance 50a plotted over the measuring angle a. The measurement vector with the highest signal strength 50s is taken as the distance value for reference, since a peak-shaped change (maximum) in the signal strength 15s (cf. reference numeral 15sp) comes from the reflection at the line with the higher degree of reflection 54I. The distance under this measurement angle is taken as the distance measurement (regardless of whether there is a maximum of 15a or not).

In the exemplary embodiment explained above, it was assumed that a measured value was always taken to determine the distance or the angle. According to the preferred embodiment, however, the measurement was carried out continuously, i. H. about the time in which the road finisher can also move. In order to take the measured values into account accordingly, in particular the measured values that were taken at the same position, an averaging can be carried out, as will be explained below.

• li = Abstandswert der jeweiligen Messung
• i= Anzahl der Messungen
• n= Anzahl der aufeinanderfolgenden annähernd gleichen Messungen
• L= mittlerer Abstandswert zur Referenzkontur

Those n measured values are selected which successively supply approximately the same distance value, with an average value being formed from these measured values. The calculation is based on the following equation: $$\overline{Abstan\mathrm{i.e}}=L=\frac{{\displaystyle {\sum }_{i=0}^{n}li}}{n}$$

• li = distance value of the respective measurement
• i= number of measurements
• n= number of consecutive measurements that are approximately the same
• L= average distance value to the reference contour

Since the distance or an angle is now available as a direct or averaged reference, starting from the determined distance or the determined th angle, either the lateral control of the finished product or the width control of the screed can be controlled, or the height of the screed can be levelled. A further exemplary embodiment therefore includes a control device 14 (cf. 6a) , which is designed, for example, to track the extendable part of the screed in such a way that the distance to the reference or the measuring angle relative to the reference remains constant. As in 6a is shown, the control device 14 receives the measurement distance from the reference or in the corresponding angle of the evaluation unit 12. According to a further exemplary embodiment, a controller can be designed to control the road finisher in such a way that the distance from the reference remains constant. Consequently, the distance values or angle values in relation to a reference contour are supplied to a steering controller, which controls the paver in such a way that the paver paves the asphalt as parallel as possible to the reference contour. Furthermore, the controller can be designed to level the height of the screed, ie to regulate or level the height of the screed.

How referring to 6a shown, the laser scanner or scanners 10 can be connected to the evaluation unit 12 via a CAN bus, RS232 or Ethernet or the like. The evaluation unit can also be connected to the control unit 14 via the CAN bus. At this point it should be noted that, for example, the control circuit for the screed can have its own evaluation unit of the control device, like the control circuit for the steering control.

Referring to 6b the evaluation unit is explained in detail. 6b shows the evaluation unit 12'. The evaluation unit 12' includes a measured value filter 12f' which filters the measurement signals received from the one or more laser scanners.

According to exemplary embodiments, the measured value filtering can take place as follows: In the evaluation unit, the individual measured vectors are initially examined for their signal amplitude in a first step. Only the measurement vectors that are in the specified measurement range and also have a high signal amplitude (high degree of reflection) are taken into account. Low signal amplitudes or a low degree of reflection is an indication that the measured value does not belong to the closer scanning range of the reference.

Additionally or alternatively, the measured value filtering can be carried out as explained above for averaging over several measured values in this measured value filter 12f.

The measured values are transferred from the measured value filter 12f' to the pattern recognition 12m', which then, as already explained above, recognizes an object, such as, e.g. B. recognizes a milled edge or a rope or a line as a pattern. Which object is recognized as a pattern is determined using a user interface, which is illustrated here using block 13b′. The user interface can, for example, be integrated into the control of the road finisher. The pattern sought in each case is selected via the user interface 13b′ and, in particular, the measurement area is also delimited. This limitation of the measuring range takes place by means of the measuring range limiter 12mb', which receives its input from the user interface 13b'. The background is that the laser scanners explained above typically cover a fairly large angular range and thus simultaneously a rope stretched at the height of the laser scanner (19 degrees compared to 10bv from 6c ) as well as a milling edge at a lower angle (e.g. 60 degrees versus 10bv from 6c ) can detect. The angular range is then limited by means of the measuring range limiter 12mb' according to the preselected reference. The delimitation takes place, for example, in such a way that the measurement filter f' arranged at the input of the evaluation unit 12' forwards only values with an angular range greater than x1 and less than x2 to the pattern recognizer 12m'. In addition, the evaluation unit also has a distance calculation 12a′, which either directly determines a distance to an object based on the measured distance value (typically evaluation of the transit time) or calculates the distance based on a detected angle of the pattern to be searched for. The distance values to the reference are then output by the unit 12a'.

According to exemplary embodiments, the evaluation unit 12' is designed to detect the reference contour based on the continuously measured distance vectors and to calculate the distance to the reference. Since all of the operations explained above take place in particular in the digital domain, the evaluation unit 12' mainly includes a microcontroller, which is connected via an interface, such as, for example, B. a serial interface (CAN, RS232 or Ethernet or similar) that receives the measurement vectors from the laser scanner.

As already explained above, the evaluation unit 12', in particular based on the function blocks 13b' and 12mb' as well as 12m', is designed to recognize different reference patterns. This can be done either automatically or optionally via the input of an operator (cf. function block 13b'), via which the measuring range (cf. 12mb') is limited.

According to a further exemplary embodiment, the reference is selected as follows: the laser scanner first scans the possible reference points (eg milled edge, rope, reference line on the wall) and identifies the existing reference or references.

If there are several references (e.g. cable and milled edge), it is up to the user to select the desired reference (cable or milled edge) by making an appropriate entry. If a clear reference has been defined, the scan area for the selected reference is limited so that the sensor is also fixed on the selected reference and no jumping between references can occur. Limiting the measurement range also has the advantage that the evaluation of the individual measurement vectors is reduced to a minimum, thereby accelerating the evaluation algorithm and significantly suppressing disturbance variables.

In the above exemplary embodiment, it was assumed that these relate to distance/steering sensors for road finishers. Since a sensor system is explained here, this is of course also applicable to other machines, such as e.g. B. other construction machinery, z. B. a grader or a compaction roller can be used. With the grader, either the steering or the positioning of the displaceable tool transverse to the direction of travel (similar to the positioning of the screed or width control of the screed) or a height leveling of the tool is monitored and/or controlled with the system explained above. In this respect, the device is suitable for determining the position of the entire vehicle (construction machine in general) in particular transversely to the direction of travel for steering purposes and/or for determining the position and leveling of the displaceable/extendable tool (transversely to the direction of travel) for controlling the tool. At this point it should be pointed out once again that a particular advantage of all the implementations explained above is that one and the same laser sensor can be used for different purposes, namely one as a steering sensor directly on the paver or on the construction machine and another as a sensor for the screed or generally for extendable machine parts and as a sensor for use in leveling the height of the screed, regardless of whether the reference to be sought is on the side, diagonally to the side or below. The measurement range or the potential location of the object to be recognized is determined by the orientation of the measurement sensor and/or by the limitation of the measurement range. Viewed from another perspective, the measurement system or measurement and control system explained here creates the basis for the autonomous driving of construction machines.

Even if it was assumed in the exemplary embodiments that these are all implemented as a device, it should be pointed out at this point that a further exemplary embodiment relates to a corresponding method which can be carried out, for example, on the microcontroller of the evaluation device 12'. The method includes the basic steps of recognizing a pattern (automatically or in response to user input). The pattern recognition takes place according to exemplary embodiments as explained above and, depending on the precise implementation, laterally arranged patterns such as e.g. B. a rope or a line as well as patterns arranged at an angle to the side, such as a milled edge. Furthermore, the method of pattern recognition can also include steps of detecting a cable or a milled edge from above.

Although some aspects have been described in the context of a device, it is understood that these aspects also represent a description of the corresponding method, so that a block or a component of a device is also to be understood as a corresponding method step or as a feature of a method step. Similarly, aspects described in connection with or as a method step also constitute a description of a corresponding block or detail or feature of a corresponding device. Some or all of the method steps may be performed by hardware apparatus (or using a hardware Apparatus), such as a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, some or more of the essential process steps can be performed by such an apparatus.

Depending on particular implementation requirements, embodiments of the invention may be implemented in hardware or in software. Implementation can be performed using a digital storage medium such as a floppy disk, DVD, Blu-ray Disc, CD, ROM, PROM, EPROM, EEPROM or FLASH memory, hard disk or other magnetic or optical memory, on which electronically readable control signals are stored, which can interact or interact with a programmable computer system in such a way that the respective method is carried out. Therefore, the digital storage medium can be computer-readable.

Some exemplary embodiments according to the invention therefore comprise a data carrier which has electronically readable control signals which are capable of interacting with a programmable computer system to perform any of the methods described herein.

In general, embodiments of the present invention can be implemented as a computer program product with a program code, wherein the program code is operative to perform one of the methods when the computer program product runs on a computer.

The program code can also be stored on a machine-readable carrier, for example.

Other exemplary embodiments include the computer program for performing one of the methods described herein, the computer program being stored on a machine-readable carrier.

In other words, an exemplary embodiment of the method according to the invention is therefore a computer program that has a program code for performing one of the methods described herein when the computer program runs on a computer.

A further exemplary embodiment of the method according to the invention is therefore a data carrier (or a digital storage medium or a computer-readable medium) on which the computer program for carrying out one of the methods described herein is recorded. The data carrier, digital storage medium, or computer-readable medium is typically tangible and/or non-transitory.

A further exemplary embodiment of the method according to the invention is therefore a data stream or a sequence of signals which represents the computer program for carrying out one of the methods described herein. For example, the data stream or sequence of signals may be configured to be transferred over a data communication link, such as the Internet.

Another embodiment includes a processing device, such as a computer or programmable logic device, configured or adapted to perform any of the methods described herein.

Another embodiment includes a computer on which the computer program for performing one of the methods described herein is installed.

A further exemplary embodiment according to the invention comprises a device or a system which is designed to transmit a computer program for carrying out at least one of the methods described herein to a recipient. The transmission can take place electronically or optically, for example. For example, the recipient may be a computer, mobile device, storage device, or similar device. The device or the system can, for example, comprise a file server for transmission of the computer program to the recipient.

In some embodiments, a programmable logic device (e.g., a field programmable gate array, an FPGA) may be used to perform some or all of the functionality of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform any of the methods described herein. In general, in some embodiments, the methods are performed on the part of any hardware device. This can be hardware that can be used universally, such as a computer processor (CPU), or hardware that is specific to the method, such as an ASIC.

The devices described herein may be implemented, for example, using hardware apparatus, or using a computer, or using a combination of hardware apparatus and a computer.

The devices described herein, or any components of the devices described herein, may be implemented at least partially in hardware and/or in software (computer program).

The methods described herein may be implemented, for example, using hardware apparatus, or using a computer, or using a combination of hardware apparatus and a computer.

The methods described herein, or any components of the methods described herein, may be performed at least in part by hardware and/or by software.

The embodiments described above are only an illustration of the principles of the present invention. It is understood that modifications and variations to the arrangements and details described herein will occur to those skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the following claims and not by the specific details presented in the description and explanation of the embodiments herein.

Claims (21)

Road finisher (50) with a screed with an extendable part and a sensor system (1), with the following features: a laser scanner (10), which is arranged on the extendable part of a screed (50b) of the road finisher (50) and is designed to search a predetermined angular range for one or more objects and corresponding distance values that indicate the distance to the one or more Describe objects, together with corresponding intensity values, which describe an intensity of a reflection occurring at the one or more objects, to be determined via angles of the specified angle range, an evaluation unit (20) which is designed to recognize an object as a reference (54, 54s, 54k) together with an associated angle based on a known pattern, comprising the distance values and the intensity values over the scanning angle, and which is designed determine a distance to the reference (54, 54s, 54k) and the angle from the reference (54, 54s, 54k); and a controller that is designed to move the extendable part or parts of the screed (50b) and/or the screed (50b) based on the distance to the reference (54, 54s, 54k) and the angle relative to the reference (54, 54s , 54k). Paver (50) according to claim 1 , wherein the evaluation unit (20) is designed to recognize different types of objects as reference (54, 54s, 54k) based on different known patterns. Paver (50) according to claim 2 , wherein the evaluation unit (20) receives a user selection via a user interface, which characterizes the type of object to be recognized. Road finisher (50) according to one of the preceding claims, wherein the distance to be determined from the reference (54, 54s, 54k) is a lateral distance a between the laser scanner (10) and the reference (54, 54s, 54k). Road paver (50) according to any one of the preceding claims, wherein the object to be detected is a rope (54s). Paver (50) according to claim 5 , wherein the evaluation unit (20) recognizes the cable (54s) when a maximum of the intensity values is in the form of a peak and when a minimum of the distance values is in the form of a peak or when a maximum of the intensity values is in the form of a peak and a minimum of the distance values is in the form of a peak at the same angle in the given angle range. Paver (50) according to claim 5 or 6 , wherein the evaluation unit (20) is designed to detect the cable (54s) from a bird's-eye view and to determine the angle α in the specified angle range or to detect the cable (54s) from a bird's-eye view and to determine the angle α in the specified To determine the angular range in order to calculate the distance a using the formula a = tan α · height h, starting from the determined angle α. Road finisher (50) according to one of Claims 5 until 7 , wherein the evaluation unit (20) is designed to recognize the cable (54s) in a lateral perspective and to determine the distance from the cable (54s). Road finisher (50) according to one of the preceding claims, wherein the evaluation unit (20) is designed to detect an edge (54k), in particular a milled edge or curb. Paver (50) according to claim 9 , wherein the evaluation unit (20) determines the edge (54k) in a lateral perspective if the intensity values form an elevation within an angular range of the predetermined angular range or if the distance values form a plateau of the distance values within an angular range of the predetermined angular range or if a combination of there is a plateau in the distance values and an increase in the intensity values in an angular range of the predefined angular range. Paver (50) according to claim 9 or 10 , wherein the evaluation unit (20) determines the edge (54k) in a bird's-eye view if the distance values form a jump at an angle of the predetermined angular range or if the distance values form a maximum at an angle of the predetermined angular range or if the distance values at an angle of the form a jump within the predetermined angular range and the distance values form a maximum at the angle of the predetermined angular range. Paver (50) according to claim 11 , wherein the evaluation unit (20) is designed to calculate the distance a using the formula a=tan a, based on the determined angle of the angle range. to determine the height h. Road finisher (50) according to one of the preceding claims, wherein the evaluation unit (20) is designed to recognize a line (541) in a lateral perspective on a wall or in a bird's-eye view on a subsurface. Paver (50) according to Claim 13 , the line (541) being recognized when a maximum of the intensity values is obtained in the form of a peak at an angle of the predetermined angular range in combination with a continuously varying distance value. Road finisher (50) according to one of the preceding claims, wherein the evaluation unit (20) is designed to determine a plurality of n distance values over a period of time or distance covered or to determine a plurality of n distance values over a period of time or distance covered and the n distance values to be determined using the following formula: $$\overline{Abstan\mathrm{i.e}}=L=\frac{{\displaystyle {\sum }_{i=0}^{n}li}}{n}$$

where I _i is the distance value of the respective measurement, i the number of measurements, n the number of consecutive measurements and L the average distance value to the reference (54, 54s, 54k). Road finisher (50) according to one of the preceding claims, wherein the controller is designed to control the steering of the road finisher based on the distance to the reference (54, 54s, 54k) and the angle relative to the reference (54, 54s, 54k), or which is designed to control the steering based on the distance from the reference (54, 54s, 54k) and the angle relative to the reference (54, 54s, 54k), taking into account distances from the laser scanner (10) to a machine fixed point of the road finisher . Paver (50) according to Claim 16 , A first laser scanner (10) being arranged laterally in the area of a front side of the road finisher or laterally on an opposite side of the road finisher (50) with respect to a screed (50b) of the road finisher (50). Road finisher (50) according to one of Claims 1 until 17 , wherein the sensor system (1) further comprises a first laser scanner (10) or a first, third and fourth laser scanner (10) and wherein the first laser scanner (10) on the road finisher (50) on a first side and wherein the laser scanner (10 ), which is arranged on the extendable part of the screed (50b) on the first side, represents the second laser scanner (10). Paver (50) according to Claim 18 , wherein the sensor system (1) has a controller which is designed to control the extendable parts of the screed (50b) or the screed (50b) based on the distance from the reference (54, 54s, 54k) and the angle relative to the reference ( 54, 54s, 54k) or which is designed to control the extendable parts of the screed (50b) or the screed (50b) based on the distance to the reference (54, 54s, 54k) and the angle with respect to the reference (54 , 54s, 54k) taking into account the distances of the first and second laser scanners (10) from a machine fixed point of the road finisher. Paver (50) according to Claim 18 or 19 , wherein the sensor system (1) has a controller which is designed to control the extendable parts of the screed (50b) or the screed (50b) based on the vertical distance to the reference (54, 54s, 54k), or which is designed is to control the extendable parts of the screed (50b) or the screed (50b) based on the vertical distance to the reference (54, 54s, 54k), taking into account the distances of the first and second laser scanners (10) to a machine fixed point of the road finisher . Paver (50) according to claim 20 , wherein the controller is designed to take into account the extendable parts of the screed (50b) or the screed (50b) based on the distance to the reference (54, 54s, 54k) and the angle relative to the reference (54, 54s, 54k). to control the distances of the first and second laser scanners (10) to a machine fixed point of the road finisher.

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