Method for controlling a surface-modifying machine

• US 7,899,598 B2
• Filed: 05/24/2005
• Issued: 03/01/2011
• Est. Priority Date: 05/24/2004
• Status: Active Grant

• Current Assignee: Leica Geosystems AG (Hexagon AB)
• Original Assignee: Leica Geosystems AG (Hexagon AB)
• Inventors: Stegmaier, Peter A., Woon, Clement, Schneider, Klaus, Nix, Martin
• Primary Examiner(s): Tran; Khoi
• Assistant Examiner(s): Sample; Jonathan L
• Application Number:
  US11/569,556
• Publication Number:
  US 20070214687A1
• Time in Patent Office: 2,107 Days
• Field of Search: None
• US Class Current: 701/50
• CPC Class Codes: E02F 3/842 using electromagnetic, optical or photoelectric beams, e.g. laser beams
• CPC Class Codes: E02F 9/2045 Guiding machines along a predetermined path for graders E02F3/841; machines for construction of roads E01C19/004
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G06T 17/30 Polynomial surface description

Abstract

The invention relates to a method for controlling a surface-modifying machine, wherein information on the desired condition and on the actual condition of ground to be prepared is provided and is used to derive control statements for the machine based on a comparison of the desired and the actual condition. The information on the actual condition is represented by a point cloud as a spatial distribution of discrete surface points. In order to derive control statements, at least two surface points each from the point cloud are used for every horizontal position so that non-differentiated information can be derived that for example also allow to identify various planes.

Claims

1. A method for controlling a surface-modifying machine, the method comprising the acts of:

providing information about the desired condition of a surface to be prepared;

providing a point cloud recorded by a distance-measuring scanner system as a spatial distribution of discrete surface points and as information about the actual condition of the surface;

deriving a control instruction for the machine by comparison of the desired condition and the point cloud; and

controlling the machine according to the derived control instruction,

wherein, for a spatial position, the comparison of the desired condition and the point cloud uses at least two surface points of the point cloud together when deriving a single control instruction.

2. The method as claimed in claim 1, wherein the comparison of desired condition and point cloud for each spatial position of the desired condition uses surface points of at least two spatial positions of the actual condition when deriving the control instruction.

3. The method as claimed in claim 1, wherein at least one surface which represents or approximates a possible actual surface of the actual condition is coordinated with the at least two surface points.

4. The method as claimed in claim 3, wherein the assigned surface is derived by at least one of the following methods:

least squares method, fuzzy logic method, image processing method, pattern recognition, and heuristic method.

5. The method as claimed in claim 1, wherein, for each spatial position of the actual condition, the spatial difference of at least two assigned surface points is used when deriving the control instruction.

6. The method as claimed in claim 1, wherein the provision of the point cloud includes an update of the point cloud while carrying out the method.

7. The method as claimed in claim 6, wherein the scanning of a prepared surface section is through a LIDAR scan.

8. The method as claimed in claim 6, wherein, on provision of the point cloud, fitting of the prepared surface section into the point cloud is effected by at least one of:

image processing methods, pattern recognition methods, and absolute referencing of the scan fixed point.

9. The method as claimed in claim 1, wherein the point cloud is composed of distinguishable subsets of surface points.

10. The method as claimed in claim 1, wherein the point cloud is composed of distinguishable subsets of surface points a characterizing quantity being coordinated with the respective subsets.

11. The method as claimed in claim 1, wherein the number of surface points which is coordinated with the spatial position is variable.

12. The method as claimed in claim 1, wherein the surface points coordinated with a spatial position are aggregated.

25. The method as claimed in claim 1, wherein the at least two surface points of the point cloud are linked with one another, when deriving the control instruction.

26. The method as claimed in claim 1, wherein at least one plane which represents or approximates a possible actual surface of the actual condition is coordinated with the at least two surface points.

27. The method as claimed in claim 1, wherein, for each spatial position of the actual condition, the height difference of at least two assigned surface points is used when deriving the control instruction.

28. The method as claimed in claim 1, wherein the provision of the point cloud includes an update of the point cloud while carrying out the method, in particular by scanning of a prepared surface section.

29. The method as claimed in claim 10, wherein the characterizing quantity is at least one of a time mark and a spectral range.

30. The method as claimed in claim 1, wherein the number of surface points which is coordinated with the spatial position is variable as a function of at least one of time and location.

31. The method as claimed in claim 1, wherein the surface points coordinated with a spatial position are aggregated by the use of a weighting function.

13. A computer program product as a record on a non-transitory data medium, the product comprising:

information provided about the desired condition of a surface to be prepared;

a point cloud recorded by a distance-measuring scanner system as a spatial distribution of discrete surface points and as information about the actual condition of the surface;

a control instruction for the machine derived by comparison of desired condition and point cloud; and

a machine controlled according to the derived control instruction,

wherein, for a spatial position, the comparison of desired condition and point cloud uses at least two surface points of the point cloud together when a single control instruction is derived.

14. The product as claimed in claim 13, wherein the comparison of desired condition and point cloud for each spatial position of the desired condition uses surface points of at least two spatial positions of the actual condition when deriving the control instruction.

15. The product as claimed in claim 13, wherein at least one surface, or one plane, which represents or approximates a possible actual surface of the actual condition is coordinated with the at least two surface points.

16. The product as claimed in claim 15, wherein the assigned surface is derived by at least one of the following methods:

least squares method, fuzzy logic method, image processing method, pattern recognition, and heuristic method.

17. The product as claimed in claim 13, wherein, for each spatial position of the actual condition, the spatial difference, or height difference, of at least two assigned surface points is used when deriving the control instruction.

18. The product as claimed in claim 13, wherein the provision of the point cloud includes an update of the point cloud while carrying out the method by scanning of a prepared surface section.

19. The product as claimed in claim 18, wherein the scanning of a prepared surface section is through a LIDAR scan.

20. The product as claimed in claim 18, wherein, on provision of the point cloud, fitting of the prepared surface section into the point cloud is effected by at least one of:

image processing methods, pattern recognition methods, and absolute referencing of the scan fixed point.

21. The product as claimed in claim 13, wherein the point cloud is composed of distinguishable subsets of surface points a characterizing quantity being coordinated with the respective subsets.

22. The product as claimed in claim 21, wherein the characterizing quantity is at least one of a time mark and a spectral range.

23. The product as claimed in claim 13, wherein the number of surface points which is coordinated with the spatial position is variable as a function of at least one of time and location.

24. The product as claimed in claim 13, wherein the surface points coordinated with a spatial position are aggregated by the use of a weighting function.

32. The product as claimed in claim 13, wherein, for the spatial position, the comparison of desired condition and point cloud uses at least two surface points of the point cloud by linking said surface points with one another when the control instruction is derived.