LEVELING CONTROLLER ADAPTION BY GROUND PROFILE ANALYSIS

Abstract

A method for adapting a leveling control of a road finishing machine comprises: detecting first ground profile data of a first ground profile of a foundation in a surrounding area of the road finishing machine at point in time t0, wherein the road finishing machine is located at position x0; detecting second ground profile data of a second ground profile of the foundation in a surrounding area of the road finishing machine at point in time t1, wherein the road finishing machine is located at position x1, and the second ground profile partially overlaps the first ground profile; determining a translational and rotational matrix which maps a movement of the road finishing machine in space from the point in time t0 to the point in time t1; creating corrected ground profile data from the ground profile data by means of the matrix; determining an analysis region LA comprising at least a section of the first ground profile data L0 and/or a section of the corrected ground profile data; analyzing the analysis region; adapting the leveling control for a distance of the analysis region by means of data obtained in the analysis.

Claims

1. A method for adapting a leveling control of a road finishing machine, comprising: detecting first ground profile data L0 of a first ground profile B0 of a foundation in a surrounding area of the road finishing machine at a point in time t0, wherein the road finishing machine is located at position x0; detecting second ground profile data L1 of a second ground profile B1 of the foundation in a surrounding area of the road finishing machine at a point in time t1, wherein the road finishing machine is located at position x1, and the second ground profile B1 partially overlaps the first ground profile B0; determining a translational and rotational matrix M which maps a movement of the road finishing machine in space from the point in time t0 to the point in time t1; creating corrected ground profile data L1′ from the second ground profile data L1 by means of the matrix M; determining an analysis region LA comprising at least a section of the first ground profile data L0 and/or a section of the corrected ground profile data L1′; analyzing the analysis region LA, including determining changes of height; and adapting the leveling control of the road finishing machine for a distance of the analysis region LA by means of data obtained in the analyzing the analysis region LA.

2. The method according to claim 1 further comprising controlling, by the leveling control, a towing point height of a towing point between a screed and a chassis of the road finishing machine.

3. The method according to claim 1, wherein the first ground profile B0 and the second ground profile B1 are one- or two-dimensional and have at least one direction in space parallel to a direction of travel of the road finishing machine.

4. The method according to claim 1, wherein the leveling control comprises at least one of the following controllers: a robust control, an H-infinity control, a model predictive control, and/or a PID controller.

5. The method according to claim 1, wherein the adapting the leveling control comprises selection of one or more leveling sensors which are arranged at different positions in a longitudinal direction of the road finishing machine.

6. The method according to claim 1, wherein the adapting the leveling control is accomplished taking into consideration a wavelength spectrum of changes of height of the foundation and/or detected amplitudes of changes of height determined during the analyzing the analysis region LA.

7. The method according to claim 1, wherein the adapting the leveling control is accomplished on based on a selective weighting of wavelengths of detected changes of height.

8. The method according to claim 1, wherein the determination of the translational and rotational matrix M is effected by means of a scan matching algorithm, in particular an iterative algorithm.

9. The method according to claim 1, wherein the determining the translational and rotational matrix M comprises processing of position data determined by means of a GNSS module, and/or processing of travel drive data and/or processing of stationary georeferencing.

10. The method according to claim 1, wherein the analyzing the analysis region LA comprises a Fast Fourier Transformation and/or a discontinuity detection.

11. The method according to claim 1, wherein layer thickness of an already laid pavement is measured and the adapting the leveling control is accomplished taking into consideration the measured layer thickness.

12. The method according to claim 1, wherein the method is performed for two or several adjacent measuring paths y1, y2 by means of two or several ground profiles scanners arranged at the road finishing machine.

13. A road finishing machine comprising a screed and a chassis, wherein the screed is hinged to the chassis by a screed arm via a towing point, and a towing point height is adjustable by a leveling cylinder, wherein the road finishing machine furthermore comprises at least one leveling sensor, at least one ground profile scanner, and a control system with a leveling controller configured to control the towing point height taking into consideration data of the at least one leveling sensor, and wherein the control system is configured to parameterize the leveling controller based on data detected with the at least one ground profile scanner.

14. The road finishing machine according to claim 13, wherein the at least one leveling sensor comprises two or several leveling sensors which are arranged along a longitudinal direction of the road finishing machine, wherein the control system is configured to select, based on the data detected with the at least one ground profile scanner, one or several leveling sensors to be used with the leveling controller.

15. The road finishing machine according to claim 13, wherein the at least one ground profile scanner comprises a laser scanner.

16. The road finishing machine according to claim 13, wherein the at least one ground profile scanner comprises two or several ground profile scanners.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In the following, exemplified embodiments of the disclosure are described more in detail with reference to the figures. In the drawings:

[0035] FIG. 1 shows a side view of a road finishing machine with a ground profile scanner;

[0036] FIG. 2 shows a rear view of a road finishing machine with two ground profile scanners;

[0037] FIG. 3 shows a schematic view of a ground profile detection at the point in time t0;

[0038] FIG. 4 shows a lateral schematic view of a ground profile detection at the point in time t0 and a ground profile detection at the point in time t1;

[0039] FIG. 5 shows a schematic plan view of a ground profile detection at the point in time t0 and a ground profile detection at the point in time t1; and

[0040] FIG. 6 shows a flowchart of a method for the adaption of the leveling control of a road finishing machine.

[0041] Corresponding components are always provided with the same reference numerals in the figures.

DETAILED DESCRIPTION

[0042] FIG. 1 shows a road finishing machine 1 with a screed 3, a chassis 5, a material bunker 7, and a ground profile scanner 9. The screed 3 is hinged to the chassis 5 by means of a screed arm 11 via a towing point 13. The towing point 13 is height adjustable by means of a leveling cylinder 15 and has a height H with respect to a height reference, for example a guiding wire or a foundation 17. Three leveling sensors 19 are arranged at the screed arm 11 at different positions in a longitudinal direction F of the road finishing machine 1. The road finishing machine 1 furthermore comprises a control system 21 which is suited for sending, receiving, and processing data, and an antenna 23 for sending and/or receiving data, for example a GNSS signal. To this end, the antenna 23 can be connected with a GNSS module 24 which in turn is connected with the control system 21. The ground profile scanner 9 detects a ground profile of the foundation 17 on which the road finishing machine 1 is moving in the direction of travel x and is laying paving material 25 by means of the screed 3 to form a new pavement 27 with a layer thickness S. The ground profile scanner 9 of the shown embodiment is a laser scanner and scans the surface of the foundation 17 with a laser beam 29. The laser beam 29 is pivotable about an axis transverse to the direction of travel x to detect ground profile data longitudinally to the direction of travel x by means of a line scan. The ground profile data serve as a basis for parameterizing a leveling controller 31 which can be part of the control system 21.

[0043] FIG. 2 shows a rear view of a road finishing machine 1 with a screed 3, a chassis 5, an antenna 23, and two ground profile scanners 9. With this arrangement of two ground profile scanners 9, two ground profiles that are parallel in the direction of travel x can be detected.

[0044] FIG. 3 shows a schematic view of a ground profile detection at the point in time t0, where the road finishing machine 1 is located at a position x0. A laser beam 29 emitted by the ground profile scanner 9 successively scans a first ground profile B0 of the foundation 17 parallel to the direction of travel x. For this, the laser beam 29 can be pivoted about a y-axis transverse to the direction of travel x which is represented here by several lines for the time history of the position of the laser beam 29. The first ground profile B0 is detected by a line scan, where the ground profile scanner 9 is located at a certain position y. The y-axis extends transversely to the direction of travel x. The generated first data points 33 together form the first ground profile data L0 of the first ground profile B0 which can be stored and processed, in particular by the control system 21.

[0045] FIG. 4 shows a lateral schematic view of a first ground profile detection at the point in time t0 according to FIG. 3 and a second ground profile detection at the point in time t1. As in FIG. 3, the first data points 33 generated at the point in time t0 which together form the first ground profile data L0 are represented as hollow circles. The second data points 35 generated at the point in time t1 which together form the second ground profile data L1 are represented as solid circles. In an overlap region T, the first ground profile data L0 and the second ground profile data L1 overlap. From the point in time t0 to the point in time t1, the road finishing machine 1 has moved according to the vector V and has performed, due to the ground irregularity, a rotation, for example a tilting, as is represented by the shown coordinate systems. The overlap region T is the starting basis for determining the translational and rotational matrix M which maps the movement of the road finishing machine 1 from the point in time t0 to the point in time t1. The determination of the translational and rotational matrix M can be effected by means of a scan matching algorithm, in particular by means of an iterative closest point algorithm (ICP) by means of the first data points 33 and the second data points 35. For adapting the leveling control, a suited analysis region LA is selected whose changes of height are analyzed. The analysis region LA can comprise data points 33, 35 of the first ground profile data L0 and the second ground profile data L1. For example, the analysis region LA can have a length of 5 meters.

[0046] FIG. 5 shows a schematic plan view of a ground profile detection at the point in time t0, and a ground profile detection at the point in time t1, wherein two parallel line scans are performed at the positions y1 and y2 by means of two ground profiles scanners 9. The overlap region T in which the first data points 33 of the first ground profile data L0 and the second data points 35 of the second ground profile data L1 overlap is shown. The left line scan at position y1 and the right line scan at position y2 can be combined, for example by averaging, for an adaption of a leveling control. The left line scan and the right line scan can, however, also be used separately for adapting one separate leveling control each of a left and a right towing point 13.

[0047] FIG. 6 shows a flowchart of a method 100 for the adaption of a leveling control of a road finishing machine 1. The following procedure steps are performed:

[0048] 101—Detecting first ground profile data L0 of a first ground profile B0 of the foundation 17 in a surrounding area of the road finishing machine 1 at the point in time t0, wherein the road finishing machine 1 is located at position x0.

[0049] 103—Detecting second ground profile data L1 of a second ground profile B1 of the foundation 17 in a surrounding area of the road finishing machine 1 at the point in time t1, wherein the road finishing machine 1 is located at position x1, and the second ground profile B1 partially overlaps the first ground profile B0.

[0050] The detection of the ground profile data B0, B1 can be effected by a line scan with the ground profile scanner 9.

[0051] 105—Determining the translational and rotational matrix M which maps a movement of the road finishing machine 1 in space from the point in time t0 to the point in time t1. For determining the translational and rotational matrix M, the data of a distance determination 107 which determines, for example by means of a GNSS receiver and/or sensors of the travel drive of the road finishing machine 1, position data of the road finishing machine 1 can be consulted.

[0052] 109—Creating corrected ground profile data L1′ from the ground profile data L1 by means of the matrix M. As a result, continuous ground profile data Lges' are obtained which can extend up to a length corresponding to the sum from the first ground profile B0 and the second ground profile B1. More than two corresponding ground profile data can also be detected, corrected, and combined.

[0053] 111—Determining an analysis region LA comprising at least a section of the ground profile data L0 and/or a section of the corrected ground profile data L1′. The analysis region LA can also comprise further corrected ground profile data Ln′. The analysis region LA can conveniently be determined anew in the course of the laying operation. For example, the analysis region LA can comprise a length of 5 m each, and thus, adjacent analysis regions LA can be defined which each represent the basis for the further procedure steps.

[0054] 113—Analyzing the analysis region LA, in particular determining changes of height. The analysis can comprise a Fast Fourier Transformation and/or a discontinuity detection, in particular the formation of differences. As a result of this procedure step, the changes of height of the foundation 17 in the analysis region LA are known. In particular, the analysis can indicate a wavelength spectrum of the changes of height, indicate the frequency and amplitude of a wavelength spectrum and individual changes of height, and indicate singular changes of height, such as for example steps.

[0055] 115—Adapting the leveling control for the distance of the analysis region LA by means of the data obtained by the analysis. For example, in response to a determined wavelength, the parameters of the employed controller or controllers can be adjusted. For example, the parameters P_n, l_n, D_n of a PID controller can be adjusted. Equally, the parameters of the controller, in particular the PID controller, can be adjusted in response to a single irregularity, for example a step. Furthermore, l to k of the present k leveling sensors 19 can be selected for the subsequent leveling control 117.

[0056] 117—Leveling control during the paving operation. With the adapted leveling control 31, the laying of the paving material 25 into a road pavement 27 is accomplished. In the process, the leveling control 31 controls the leveling cylinders 15 to adjust the towing point height H.

[0057] 119—Measuring the pavement. The newly laid road pavement 27 can be measured, for example to determine a layer thickness. These measuring results can then additionally influence the leveling control 117 as a feedback mechanism.

[0058] As those skilled in the art will understand, the control system 21, the leveling control 31, as well as any other controller, unit, component, module, system, subsystem, interface, sensor, device, or the like described herein may individually, collectively, or in any combination comprise appropriate circuitry, such as one or more appropriately programmed processors (e.g., one or more microprocessors including central processing units (CPU)) and associated memory, which may include stored operating system software, firmware, and/or application software executable by the processor(s) for controlling operation thereof and for performing the particular algorithm or algorithms represented by the various methods, steps, functions and/or operations described herein, including interaction between and/or cooperation with each other. One or more of such processors, as well as other circuitry and/or hardware, may be included in a single Application-Specific Integrated Circuit (ASIC), or several processors and various circuitry and/or hardware may be distributed among several separate components, whether individually packaged or assembled into a System-on-a-Chip (SoC).