Guidance of a cutting head in relation to a material by using sensor delay time

Patent metadata

Field	Value
Publication number	US-11267073-B2
Application number	US-201917272100-A
Country	US
Kind code	B2
Filing date	Aug 16, 2019
Priority date	Aug 27, 2018
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

In a method for guiding a cutting head in relation to a material, a position and a speed of the cutting head are set by means of a drive unit depending on a desired position value and a desired speed value established by an interpolator unit, a control signal for the drive unit is determined, a distance between the cutting head and the material is determined with a distance sensor, and a corresponding distance signal is provided. The distance signal is compared with a predetermined comparison distance to yield a distance-control signal, and the control signal for the drive unit is additionally determined dependent upon a distance-control signal. The comparison distance is subtracted from the distance signal and the difference is superimposed on the actual position signal, which is delayed by a first time period, wherefrom the distance-control signal is determined.

First claim

What is claimed is:

1. A method for guiding a cutting head in relation to a material, said method comprising:
providing with an interpolator unit a position setpoint value and a speed setpoint value for guiding the cutting head;
determining from the position setpoint value a setpoint location signal, comparing in a first comparison an actual location signal provided by a drive unit with the setpoint location signal;
setting with the drive unit a position and a speed of the cutting head in relation to the material dependent upon the position setpoint value and the speed setpoint value;
detecting with a distance sensor a distance between the cutting head and the material and providing a distance signal;
in a second comparison, subtracting a pre-determined comparison distance from the distance signal to generate a difference signal and superposing the difference signal on the actual location signal which is delayed by a first timespan and determining therefrom a limited distance control signal, wherein the first timespan is dependent upon a delay time of the distance sensor required by the distance sensor to provide the corresponding distance signal for a detected distance,
determining a control signal for the drive unit dependent upon the first comparison, the speed setpoint value and the limited distance control signal, and
cutting the material by moving the cutting head relative to the material commensurate with the determined control signal.

2. The method of claim 1 , further comprising, for determining the first timespan, moving the cutting head commensurate with a pre-determined movement profile and evaluating the distance signal of the distance sensor accordingly.

3. The method of claim 1 , wherein the first timespan is determined at a pre-determined time point.

4. The method of claim 1 , further comprising moving the cutting head into a pre-determined start position.

5. The method of claim 1 , wherein the distance control signal is alternatingly determined by using the delayed actual location signal and by using a conventional distance control signal without a time delay.

6. The method of claim 1 , wherein the control signal is determined by a temporal change in the setpoint location signal dependent upon the first comparison.

7. The method of claim 1 , wherein determining the setpoint location signal from the position setpoint value further comprises delaying the setpoint location signal being relative to the position setpoint value by a pre-determined second timespan.

8. A computer program product embodied in a computer-readable non-transitory medium and comprising program code which when loaded into a memory of a processor of a control facility, which guides a cutting head in relation to a material in order to make a cut in the material by means of a cutting process carried out by the cutting head due to a relative movement of the cutting head in relation to the material, and executed by the processor, causes the control facility to
provide with an interpolator unit a position setpoint value and a speed setpoint value for guiding the cutting head,
determine from the position setpoint value a setpoint location signal, compare in a first comparison an actual location signal provided by a drive unit with the setpoint location signal,
set with the drive unit a position and a speed of the cutting head in relation to the material dependent upon the position setpoint value and the speed setpoint value,
detect with a distance sensor a distance between the cutting head and the material and providing a distance signal,
in a second comparison, subtract a pre-determined comparison distance from the distance signal to generate a difference signal and superpose the difference signal on the actual location signal which is delayed by a first timespan and determine therefrom a limited distance control signal, wherein the first timespan is dependent upon a delay time of the distance sensor required by the distance sensor to provide the corresponding distance signal for a detected distance,
determine a control signal for the drive unit dependent upon the first comparison, the speed setpoint value and the limited distance control signal, and
cut the material by moving the cutting head relative to the material commensurate with the determined control signal.

9. A control facility for guiding a cutting head in relation to a material in order to make a cut in the material by means of a cutting process carried out by the cutting head due to a relative movement of the cutting head in relation to the material, the control facility comprising:
a first input receiving from an interpolator unit a position setpoint value and a speed setpoint value for guiding the cutting head,
a second input receiving from a distance sensor a distance signal indicating a distance between the cutting head and the material,
an output supplying to a drive unit a position and a speed of the cutting head in relation to the material based on a control signal which depends on the position setpoint value and the speed setpoint value, for which purpose the control facility is configured to,
determine from the position setpoint value a setpoint location signal, compare in a first comparison an actual location signal provided by a drive unit with the setpoint location signal,
set with the drive unit the position and the speed of the cutting head,
provide a distance signal based on the detected distance between the cutting head and the material,
in a second comparison, subtract a pre-determined comparison distance from the distance signal to generate a difference signal and superpose the difference signal on the actual location signal which is delayed by a first timespan and determining therefrom a limited distance control signal, wherein the first timespan is dependent upon a delay time of the distance sensor required by the distance sensor to provide the corresponding distance signal for a detected distance between the cutting head and the material,
determine a control signal for the drive unit dependent upon the first comparison, the speed setpoint value and the limited distance control signal, and
cut the material by moving the cutting head relative to the material commensurate with the determined control signal.

Assignees

• Siemens Ag

Inventors

• Forster Gerhard
• Geissdörfer Klaus
• Hamm Carsten
• Schäfers Elmar

Classifications

• G05B2219/49362

  Tool, probe at constant height to surface during machining · CPC title

• B23K2103/52

  Ceramics · CPC title

• B23K26/048 Primary

  by controlling the distance between laser head and workpiece · CPC title

• G05B19/19

  characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path · CPC title

• B23K26/083

  Devices involving movement of the workpiece in at least one axial direction · CPC title