Method and system for vibration avoidance for automated machinery

• US 7,957,832 B2
• Filed: 03/25/2009
• Issued: 06/07/2011
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: Teknic, Inc.
• Original Assignee: Teknic, Inc.
• Inventors: Testa, Francis Joseph
• Primary Examiner(s): Hartman, Jr.; Ronald D
• Application Number:
  US12/410,818
• Publication Number:
  US 20090204236A1
• Time in Patent Office: 804 Days
• Field of Search: 700186-189, 700/280, 318/570, 318/573, 735/70
• US Class Current: 700/187
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/41117 Cancel vibration during positioning of slide
• CPC Class Codes: G05B 2219/49054 Active damping of tool vibration

Abstract

A method for vibration avoidance in automated machinery produces actuator space-time contours that meet design objectives of the machinery while suppressing energy content at frequencies in the space-time contour, by concatenating multiple space-time contour segments together in such a way as to be mostly free of energy at the frequencies of interest while meeting other specified design goals. The segments used to construct these frequency-optimized-contours are a series of concatenated polynomial segments, the independent variable t being time. These segments can define the variable to be controlled (e.g. speed or distance) versus time, or define one of the controlled variable'"'"'s time-derivatives (e.g., the slope of the speed vs. time, etc.). When these frequency-optimized-contours are fed as a command to a machine controller through an actuator or actuators, the energy at the frequencies of interest is low enough to avoid deleterious vibration from occurring while still meeting the machine performance objectives.

Claims

1. A method for providing a frequency-optimized contour to a machine control system requiring a contour comprising a physical variable to be controlled which changes with time as an independent variable during machine run time, comprising:

a) creating a database of frequency-optimized contours by the steps of;

i) finding a plurality of constraints for a set of contours such that, for each contour that is required during machine run time, there is at least one contour within the set that can be scaled to fit the requirement;

ii) producing a set of frequency-optimized-contours that meets said constraints; and

iii) storing said set of frequency-optimized-contours in a frequency-optimized-contour database; and

b) determining an application requirement for a use of the machine control system;

c) finding a frequency-optimized contour in the database that is suitable for scaling to meet the application requirement; and

d) scaling the frequency-optimized contour found in step c by multiplying a variable by a constant;

e) providing the scaled frequency optimized contour to the machine control system.

2. The method of claim 1, where the constant in step d is fixed as the number one.

3. The method of claim 1, in which the variable in step d) is the time variable, and the multiplication by a constant is performed equally throughout the contour to produce the scaled contour.

4. The method of claim 1, in which the variable in step d) is the physical variable, and the multiplication by a constant is performed equally at all points in time to produce the scaled contour.

5. A method for providing frequency-optimized contours to a machine control system requiring a contour comprising a physical variable to be controlled which changes with time as an independent variable during machine run time, comprising:

a) creating a database of frequency-optimized contours by the steps of;

i) finding a plurality of constraints for a set of contours such that, for each contour that is required during machine run time, there is at least one contour within the set that can be scaled to fit the requirement;

ii) producing a set of frequency-optimized-contours that meets said constraints; and

iii) storing a time-derivative of each of the said set of frequency-optimized-contours in a frequency-optimized-contour database; and

b) determining an application requirement for a use of the machine control system;

c) finding a frequency-optimized contour in the database that is suitable for amplitude scaling to meet the application requirement; and

d) producing a scaled frequency-optimized contour found in step c) by

multiplying a variable by a constant; and

time-integrating the variable at least once;

e) providing the scaled frequency optimized contour to the machine control system.

6. The method of claim 5, where the constant in step d) is fixed as the number one.

7. The method of claim 5, in which the variable in step d) is the time variable, and the multiplication by a constant is performed equally throughout the contour to produce the scaled contour.

8. The method of claim 5, in which the variable in step d) is a time-derivative of at least first order of the physical variable, and the multiplication by a constant is performed equally at all points in time to produce the scaled contour.