Method for Providing a Travel Profile, Control Device, Machine, and Computer Program

Abstract

A control device, a machine (tool) having the control device, a method for providing a travel profile and a computer program for providing the travel profile, wherein a reference line is generated, e.g., from a CAD drawing, to provide a travel profile for a tool, where approximation curves are created from the reference line using wavelet base functions, transformation curves are formed from the approximation curves via difference generation, and these are each adapted to a desired accuracy of the processing mode via modification, where modification curves are created via the modification of the transformation curves, where the travel profile is the sum of the modification curves, and where drive elements of the machine tool are controlled based on the travel profile such that the travel profile can be optimized via the selection of wavelet base functions, based on a processing mode, e.g. rough milling, fine milling, laser cutting.

Claims

13. A method for providing a travel profile, the method comprising: predetermining a reference line is predetermined; and defining the reference line based on points along an edge or a corner of a workpiece, the method further comprising performing at least one of (i) steps A), B), D) and E) and (ii) step C), D) and E) comprising: A) creating n approximation curves, the n approximation curves being created via an approximation based on at least one of (i) a different number and (ii) position of points comprising points from the reference line; B) creating n transformation curves, each of the n transformation curves being generated by differentiation between in each case two of the n approximation curves; C) creating n transformation curves via wavelet approximations of the reference line with wavelet base functions; D) creating n modification curves, a jth (k=1 . . . n) modification curve being generated from a jth transformation curve via a modification process; and E) creating the travel profile by adding the n modification curves.

14. The method as claimed in claim 13, wherein at least one of (i) the approximation curves and (ii) the transformation curves are wavelet base functions of a wavelet transform.

15. The method as claimed in claim 13, wherein the modification process is performed via a smoothing based on a reference value.

16. The method as claimed in claim 14, wherein the modification process is performed via a smoothing based on a reference value.

17. The method as claimed in claim 13, wherein the wavelet base functions are predetermined based on a processing mode.

18. The method as claimed in claim 13, wherein the jth approximation curve is generated by omitting each ith point in the (j1)th approximation curve.

19. The method as claimed in claim 18, wherein the jth approximation curve is generated by omitting each second point in the (j1)th approximation curve.

20. The method as claimed in claim 13, wherein the approximation curves result from an approximation of the points by polynomials, in particular B-splines.

21. The method as claimed in claim 20, wherein the polynomials are B-splines.

22. The method as claimed in claim 13, wherein the jth transformation curve is formed from a difference between the (k+2)th approximation curve and the (k+1)th approximation curve.

23. The method as claimed in claim 17, wherein reference values are predetermined based on the processing mode.

24. The method as claimed in claim 13, wherein the travel profile comprises a travel profile of a tool in a machine tool.

25. A control device for providing a travel profile, comprising: a processor; and memory; wherein at least one of (i) a reference line, (ii) support points and (iii) a G-code program are provided as input variables, the control device being configured to: predetermine a reference line is predetermined; and define the reference line based on points along an edge or a corner of a workpiece, the control device being further configured to perform at least one of (i) A), B), D) and E) and (ii) C), D) and E) comprising: A) creating n approximation curves, the n approximation curves being created via an approximation based on at least one of (i) a different number and (ii) position of points comprising points from the reference line; B) creating n transformation curves, each of the n transformation curves being generated by differentiation between in each case two of the n approximation curves; C) creating n transformation curves via wavelet approximations of the reference line with wavelet base functions; D) creating n modification curves, a jth (k=1 . . . n) modification curve being generated from a jth transformation curve via a modification process; and E) creating the travel profile (H) by adding the n modification curves.

26. The control device as claimed in claim 25, wherein the travel profile is provided to control drive elements in a machine tool.

27. The control device of claim 25, wherein the control device controls a machine tool.

28. A machine having the control device as claimed in claim 25.

29. The machine as claimed in claim 28, wherein the machine comprises a machine tool.

30. A control device encoded with a computer program which, when executed by a processor, causes the control device to provide a travel profile, the computer program comprising: program code for predetermining a reference line is predetermined; and program code for defining the reference line based on points along an edge or a corner of a workpiece, the computer program further comprising program code for performing at least one of (i) A), B), D) and E) and (ii) C), D) and E) comprising: A) program code for creating n approximation curves, the n approximation curves being created via an approximation based on at least one of (i) a different number and (ii) position of points comprising points from the reference line; B) program code for creating n transformation curves, each of the n transformation curves being generated by differentiation between in each case two of the n approximation curves; C) program code for creating n transformation curves via wavelet approximations of the reference line with wavelet base functions; D) program code for creating n modification curves, a jth (k=1 . . . n) modification curve being generated from a jth transformation curve via a modification process; and E) program code for creating the travel profile by adding the n modification curves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The invention will be described and explained below making reference to the figures, in which:

[0066] FIG. 1 shows a control device and a machine tool in accordance with the invention;

[0067] FIG. 2 shows a method for calculating a travel profile in accordance with the invention;

[0068] FIG. 3 shows an alternative method for calculating a travel profile in accordance with the invention;

[0069] FIG. 4 shows a flow chart for calculating the travel profile in accordance with the invention; and

[0070] FIG. 5 shows two travel profiles and a reference line in accordance with the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0071] FIG. 1 shows a control device SE and machine tool WZM. The machine tool WZM has a tool W, where a workpiece WS is manufactured with the aid of the tool W. The tool W is moved along a travel profile H. The movement along the travel profile H of the tool WZ is characterized by an arrow. The tool W is controlled or regulated in terms of its position via a drive controller AS. The drive controller AS is controlled by the control device SE. The drive controller AS is either part of the control device SE or a stand-alone drive controller AS, which can also be assigned to the machine tool WZM.

[0072] The control device SE receives a description, in particular a CAD drawing (referred to as CAD in the FIG.) of the workpiece WS to be manufactured. The description CAD can be realized by a parts program, an NC program or a CAD file, for instance.

[0073] A reference line S is calculated from the description CAD. The reference line S is converted with the aid of the method cited below to form the travel profile H for the tool W of the machine tool WZM. The travel profile is transferred to the drive controller AS. The drive controller AS controls the drive elements of the machine tool WZM. The drive controller AS can be equipped with a frequency converter, in particular converter with a processor unit, such as a SINAMICS by Siemens AG.

[0074] The reference line S specifies how the tool W would be moved in an ideal situation, in order to manufacture the workpiece WS. On account of physical boundary conditions, such as possible inaccuracies or a speed limitation of the drive elements, the travel profile H is determined with the aid of the control device SE to take restrictions into account.

[0075] The travel profile H is calculated from the reference line S, the processing mode BA and the reference values MZ in the control unit SE.

[0076] According to the processing mode BA, the travel profile H is either calculated with the aid of a first alternative or a second alternative.

[0077] In the first alternative (with the method steps C), D) and E)), transformation curves K4, K5, K6 (see FIG. 2) are created from the reference line S with the aid of a development of the reference lines S with the aid of wavelet base functions WBF. The transformation curves K4, K5, K6 are modified to form modification curves K7, K8, K9 while adhering to the reference values MZ in the method step D). The modification curves K7, K9, K9 are either added in a last step and thus assembled to form the travel profile H or assembled with the aid of a wavelet transform, in particular a fast wavelet transform.

[0078] In a second alternative, the reference line S is mapped in a representation of points. The approximation curves K1, K2, K3 are generated from the points such that the approximation curves K1, K2, K3 are approximated with a reduced number of points, in each case.

[0079] The approximations of the points is performed with the aid of wavelet base functions WBF or with spline functions, in particular B-splines. The wavelet base functions WBF are produced from the processing mode BA provided. The transformation curves K4, K5, K6 are created from the approximation functions K1, K2, K3 with the aid of differentiation. The transformation curves K4, K5, K6 are smoothed and thus modified to form modification curves K7, K8, K9.

[0080] In a further step, the modification curves K7, K8, K9 are added to form the travel profile H. The travel profile H is therefore the sum of the modification curves K7, K8, K9. The hitherto calculated travel profiles H and/or the wavelet base functions WBF are stored in a storage device SP in the control device SE.

[0081] The control device SE can also be realized by a computing unit, where the computing unit transmits the travel profile H with the aid of an interface to the drive controller AS of the machine tool WZM.

[0082] FIG. 2 shows a method for calculating a travel profile H. The starting point of the calculation is the reference line S, which maps a corner of the workpiece WS. The reference line S is represented by a plurality of points. In a first step A), a first approximation curve K1 is generated from the points by approximation of the total number of points of the reference line with an approximation function. A wavelet base function WBF is advantageously used as the approximation function.

[0083] A second approximation curve K2 is generated, by each second point in the representation of the reference line S being removed. The reduced quantity of points is likewise approximated. The same or another wavelet base function WBF can be used here. A third approximation curve K6 is generated, by in turn each second point being removed from the reduced quantity of points. The further reduced quantity of points is approximated in particular with a further wavelet base function WBF.

[0084] In a further method step B), a first transformation curve K4 is calculated from a difference between the second approximation curve K2 and the first approximation curve K1 (K4=K2K1). A second transformation curve K5 corresponds to the difference between the third approximation curve K3 and the second approximation curve K2 (K5=K3K2). The third transformation curve K6 corresponds to the third approximation curve K3.

[0085] In a further method step D), the transformation curves K4, K5, K6 will become modification curves K7, K8, K9 via modification based on the reference values MZ.

[0086] The modification is performed such that a region which the modification curves K7, K8, K9 are not permitted to leave is defined with the aid of the reference values MZ. If a transformation curve in one region is greater than the region, then this curve in the region is modified such that the transformation curve K4, K5, K6 returns to the region. The reference values correspond in particular to maximum deviations.

[0087] In the last step E), the modification curves K7, K8, K9 are added and the sum of the modification curves K7, K8, K9 forms the travel profile H.

[0088] FIG. 3 shows an alternative method for calculating a travel profile H. In the method shown here, the travel profile is calculated analogously to the method shown in FIG. 2, but the transformation curves K4, K5, K6 are, however, generated directly from the reference line S with the aid of a wavelet approximation.

[0089] The reference line S is transformed to form the transformation curves K4, K5, K6 with the aid of wavelet base functions WBF. B-splines are used advantageously as wavelet base functions WBF. The calculation of the first transformation curve K4 is accordingly performed by forming a scalar product of the reference line S with the first wavelet base function WBF. The second transformation curve K5 corresponds to the scalar product of the reference line S with the second wavelet base function WBF. The third transformation curve K6 corresponds to the scalar product of the reference line S with the third wavelet base function WBF. Moreover, the region that is embodied to be proportional to the reference values is shown in the second transformation curve K5. The point in the second transformation curve K5 that does not lie within the region is again disposed in the region in the second modification curve K8.

[0090] FIG. 4 shows a flow chart for the calculation of the travel profile H. A user B who allows a travel profile H to be calculated to form a predetermined reference line S or a CAD file CAD is shown. The control device SE is used for calculation purposes. The user B specifies the processing type BA and optionally reference values MZ, in particular maximum deviations.

[0091] The control device SE assigns suitable wavelet base functions WBF for calculating the travel profile H to the processing mode BA predetermined by the user B. The wavelet base functions WBF are advantageously provided for both alternative calculation methods presented, here. Furthermore, the modification of the transformation curves K4, K5, K6 is introduced for the modification of the transformation curves K4, K5, K6 based on the predetermined reference values MZ. The reference values MZ can be assigned to the processing type BA. The reference values MZ can, however, also be predetermined or changed by the user B. The reference values recreate the permitted deviations from the dimensioning of the workpiece. The reference values can, however, also represent the physical boundary conditions of the machine tool WZM when the workpiece WS is manufactured.

[0092] Maximum speeds of the drive elements of the machine tool WZM, a cut resistance of the material of the workpiece WS or a predetermined processing time are considered to be physical boundary conditions.

[0093] Milling (2D and 3D), in particular as prismatic manufacture, laser processing, in particular trimming, lasering, laser cutting or rotating, scaling, smoothing are considered to be processing modes.

[0094] A travel profile can advantageously be calculated via the invention, where the processing mode provided is noted.

[0095] FIG. 5 shows two travel profiles H and a reference line S. The reference line S is shown by a dashed line and by crosses shown spaced apart on the dashed line. The crosses symbolize the points, on the basis of which the approximation curves K1, K2, K3 are approximated.

[0096] Furthermore, a travel profile H is shown, in which the tool W does not entirely penetrate the corner shown. This travel profile H can represent the travel profile H of a rough processing mode BA with a CNC machine. The other travel profile H extends beyond the reference line S. Such a travel profile H is suitable, for instance, for guiding a tool W, which cuts out a corner in a rapid manner. The more accurate the manufacture, i.e., the smaller the maximum deviations when the workpiece W is processed, the smaller the distance of the travel profile H from the reference line S.

[0097] In summary, the invention relates to a method for providing a travel profile H and a control device SE and a machine (tool) WZM with such a control device SE. A computer program can also be provided to provide the travel profile H. A reference line S is generated, e.g., from a CAD drawing, in order to provide a travel profile H for a tool W. Approximation curves K1, K2, K3 are created from the reference line S with the aid of wavelet base functions WBF. Transformation curves K4, K5, K6 are formed from the approximation curves K1, K2, K3 by differentiation, and these are each adjusted to a desired accuracy of the processing mode BA via modification. Modification curves K7, K8, K9 are produced via modification of the transformation curves K4, K5, K6. The travel profile H is the sum of the modification curves K7, K8, K9. Drive elements of the machine tool WZM are controlled based on the travel profile H. Particularly advantageously, the provision of the travel profile (H) can be optimized via the selection of wavelet base functions (WBF) on the basis of the processing mode BA, e.g., rough milling, fine milling, or laser cutting.

[0098] Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.