System and method for setting machine limits

• US 8,380,462 B2
• Filed: 09/16/2010
• Issued: 02/19/2013
• Est. Priority Date: 09/16/2010
• Status: Active Grant

• Current Assignee: Ford Motor Company
• Original Assignee: Ford Motor Company
• Inventors: Jalluri, Chandra Sekhar, Rajoria, Himanshu, Pauli, John Christopher, Low, David P.
• Primary Examiner(s): Budd, Mark
• Application Number:
  US12/883,270
• Publication Number:
  US 20120068658A1
• Time in Patent Office: 887 Days
• Field of Search: 318/566, 318/626, 318/635, 700/159, 700/174, 702/179
• US Class Current: 702/179
• CPC Class Codes: G05B 23/0235 based on a comparison with predetermined threshold or range, e.g. "classical methods", carried out during normal operation; threshold adaptation or choice; when or how to compare with the threshold

Abstract

A system and method for setting machine limits include setting a limit for a machine parameter, setting a temporal operating range for the machine, and setting a temporal step. The machine is operated over the operating range and the machine parameter is measured. A first new limit for the machine parameter is set based at least in part on the measurements over the operating range. The operating range is advanced by the temporal step, and the machine parameter continues to be measured. Another new limit for the machine parameter is set based at least in part on the measurements over the operating range after the operating range has been advanced.

Claims

1. A method for setting machine limits, comprising:

setting a limit for a machine parameter;

setting a temporal operating range for the machine;

setting a temporal step;

operating the machine over the operating range;

measuring the machine parameter over the operating range;

setting a first new limit for the machine parameter based at least in part on the measurements over the operating range;

advancing the operating range by the temporal step;

measuring the machine parameter over the advanced operating range; and

setting a further new limit for the machine parameter based at least in part on the measurements over the advanced operating range.

2. The method of claim 1, wherein the temporal range and temporal step are both measured in machining cycles.

3. The method of claim 1, further comprising removing outlying data from the machine parameter measurements prior to the step of setting a first new limit for the machine parameter.

4. The method of claim 1, wherein the temporal step is not greater than the temporal operating range.

5. The method of claim 4, wherein the temporal operating range is initially set equal to the temporal step, the first new limit being based at least in part on the measurements over the operating range when the operating range is equal to the temporal step, the method further comprising the steps of:

(a) increasing the operating range by a predetermined amount prior to advancing the operating range by the temporal step;

(b) measuring the machine parameter over the increased operating range; and

(c) setting a second new limit for the machine parameter based at least in part on the measurements over the increased operating range.

6. The method of claim 5, further comprising:

determining a desired operating range; and

repeating steps (a)-(c) until the increased operating range equals the desired operating range, the step of advancing the operating range by the temporal step being performed when the increased operating range equals the desired operating range.

7. The method of claim 5, wherein the predetermined amount is equal to the temporal step.

8. The method of claim 1, wherein the step of setting the first new limit for the machine parameter includes not letting the first new limit exceed a predetermined maximum value.

9. The method of claim 8, wherein the step of setting a limit for the machine parameter includes setting the limit equal to the predetermined maximum value.

10. The method of claim 1, wherein the machine is a machine tool operable to perform machining operations on a workpiece using a cutting tool, the method further comprising:

manually adjusting the limit for the machine parameter after the occurrence of a predetermined event.

11. The method of claim 10, wherein the predetermined event is one of a changing of the cutting tool or a false alarm.

12. The method of claim 10, wherein the step of manually adjusting the limit for the machine parameter includes reducing the limit for the machine parameter by a predetermined amount.

13. A method for setting machine limits, comprising:

setting a temporal range for the machine;

measuring a parameter over the range;

setting a limit for the parameter based at least in part on the measurements over the range;

moving the range forward;

measuring the parameter over the moved range; and

setting a new limit for the parameter based at least in part on the measurements over the moved range.

14. The method of claim 13, wherein the temporal range is a number of machining cycles and the parameter is a vibration measurement for the machine.

15. The method of claim 14, wherein the step of moving the range forward includes moving the range forward by a predetermined number of cycles.

16. A system for setting machine limits for a machine having at least one sensor associated therewith for measuring a machine parameter and outputting signals related thereto, the system comprising:

a control system including at least one controller, the control system being programmed with a limit for the machine parameter, a temporal operating range, and a temporal step, and being configured to;

receive signals from the at least one sensor while the machine is operating over the operating range,

set a first new limit for the machine parameter based at least in part on the signals received from the at least one sensor,

advance the operating range by the temporal step,

receive signals from the at least one sensor while the machine is operating over the advanced operating range, and

set a further new limit for the machine parameter based at least in part on the signals received from the at least one sensor while the machine is operating over the advanced operating range.

17. The system of claim 16, wherein the control system is further configured to remove outlying data from the signals it receives from the at least one sensor prior to setting the first new limit for the machine parameter.

18. The system of claim 16, wherein the temporal operating range programmed into the control system is an initial temporal operating range equaling the temporal step, the first new limit being based at least in part on the signals received from the at least one sensor while the machine is operating over the initial temporal operating range.

19. The system of claim 18, wherein the control system is further configured to:

(a) increase the operating range by a predetermined amount prior to advancing the operating range by the temporal step,

(b) receive signals from the at least one sensor while the machine is operating over the increased operating range, and

(c) set a second new limit for the machine parameter based at least in part on the signals received from the at least one sensor while the machine is operating over the increased operating range.

20. The system of claim 19, wherein the control system is further programmed with a desired operating range, and is further configured to repeat steps (a)-(c) until the increased operating range equals the desired operating range, the control system performing the step of advancing the operating range by the temporal step when the increased operating range equals the desired operating range.