Freeplay monitor

• US 7,277,800 B2
• Filed: 02/28/2006
• Issued: 10/02/2007
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Sheahan, James J. Jr., Roach, Jeffrey M., Swearingen, Kevin L.
• Primary Examiner(s): Barlow; John
• Assistant Examiner(s): VO, HIEN XUAN
• Application Number:
  US11/364,644
• Publication Number:
  US 20070203656A1
• Time in Patent Office: 581 Days
• Field of Search: 702/34, 702/33, 702/182, 702/113, 244/223, 244/234, 244/196, 700/175, 700/176
• US Class Current: 702/34
• CPC Class Codes: G05B 19/4065 Monitoring tool breakage, life or condition
• CPC Class Codes: G05B 2219/41077 Self tuning, test run, detect, compute optimal backlash, deformation compensation
• CPC Class Codes: G05B 2219/42271 Monitor parameters, conditions servo for maintenance, lubrication, repair purposes
• CPC Class Codes: G05B 2219/42298 Measure backlash, time difference between point A to point B and from B to A, if too large
• CPC Class Codes: G05B 2219/50197 Signature analysis, store working conditions, compare with actual

Abstract

A system and method for monitoring freeplay within an actuator is provided. In accordance with various embodiments, the method includes collecting a plurality of actuator parameter data sets during a predetermined period. During the predetermined time period the actuator drive motor is commanded to extend and retract an actuator output ram operably connected to a movable component of a structural system such as a mobile platform. The method additionally includes selectively isolating various sets of the plurality of actuator parameter data sets that meet specific predetermined criterion. Furthermore, the method includes computing an amount of freeplay value within the actuator based on the isolated actuator parameter data sets.

Claims

1. A method for monitoring freeplay within an actuator, said method comprising:

collecting a plurality of actuator parameter data sets during a predetermined period as a drive motor of an actuator is commanded to repeatedly drive an output ram of the actuator between an extending direction and a retracting direction;

selectively isolating various sets of the plurality of actuator parameter data sets that meet specific predetermined criterion; and

computing an amount of freeplay value within the actuator based on the isolated actuator parameter data sets, the amount of freeplay indicative of an amount of mechanical wear within the actuator.

2. The method of claim 1, wherein the method further comprises:

storing the freeplay value on an electronic storage medium;

repeating the collecting of the plurality of actuator parameter data sets, the isolating of the various actuator data sets, and the computing of the freeplay value, for a plurality of subsequent predetermined periods to compile a plurality of subsequent freeplay values that are stored on the electronic storage medium; and

performing trending analysis on the compiled freeplay values to predict potential failures of the actuator.

3. The method of claim 1, wherein collecting the plurality of actuator parameter data sets comprises operating the drive motor to drive the actuator output ram in accordance with a wave form command that oscillates the drive motor operation between the extending and retracting directions.

4. The method of claim 1, wherein collecting the plurality of actuator parameter data sets comprises performing identical filtering on each of a plurality of data types included in the actuator parameter data sets to remove noise from the actuator parameter data sets.

5. The method of claim 1, wherein collecting the plurality of actuator parameter data sets comprises normalizing at least some of a plurality of data types included in the actuator parameter data sets.

6. The method of claim 1, wherein selectively isolating various sets of the plurality of actuator parameter data sets comprises isolating only those actuator parameter data sets that comprise data having values within a predetermined range.

7. The method of claim 6, wherein computing an amount of freeplay value comprises calculating the freeplay value utilizing only the isolated actuator parameter data sets.

8. The method of claim 1, wherein the method comprises substantially simultaneously collecting of the plurality of actuator parameter data sets, isolating of the various actuator data sets, and computing of the freeplay value of a plurality of actuators.

9. A method for monitoring freeplay within an actuator that controls movement of a control surface of the mobile platform, said method comprising:

generating at least;

an actuator drive motor position signal comprising a plurality of motor position data indicative of a position of a drive motor of an actuator during a predetermined data collection period as the drive motor is commanded to repeatedly drive an output ram of the actuator between an extending direction and a retracting direction;

a drive motor velocity signal comprising a plurality of motor velocity data indicative of the drive motor velocity during the data collection period, and

an actuator output ram position signal comprising a plurality of ram position data indicative of the actuator output ram position during the data collection period;

collecting a plurality of actuator parameter data sets during the data collection period, each actuator parameter data set comprising a motor position data value, a motor velocity data value and a ram position data value;

selectively isolating various sets of the plurality of actuator parameter data sets that include a motor position data value within a motor position range, a motor velocity data value within a motor velocity range and a ram position data value within a ram position range; and

computing an amount of freeplay value within the actuator for the data collection period based on the isolated actuator parameter data sets, the amount of freeplay indicative of an amount of mechanical wear within the actuator.

10. The method of claim 9, wherein the method further comprises:

storing the freeplay value on an electronic storage medium;

repeating the generation of the motor position, motor velocity and ram position signals, the collecting of the plurality of actuator parameter data sets, the isolating of the various actuator data sets, and the computing of the freeplay value, for a plurality of subsequent predetermined periods to compile a plurality of subsequent freeplay values that are stored on the electronic storage medium; and

performing trending analysis on the compiled freeplay values to predict potential failures of the actuator.

11. The method of claim 9, wherein generating the motor position, the motor velocity and the ram position signals comprises operating the drive motor to drive the actuator output ram in accordance with a wave form command that oscillates the drive motor operation between the extending and retracting directions.

12. The method of claim 9, wherein collecting the plurality of actuator parameter data sets comprises performing identical filtering on each of the motor position signal, the motor velocity signal and the ram position signal to remove noise from the motor position signal, the motor velocity signal and the ram position signal.

13. The method of claim 9, wherein collecting the plurality of actuator parameter data sets comprises normalizing the motor position signal and the ram position signal.

14. The method of claim 9, wherein computing an amount of freeplay value comprises calculating a mean value of the lag between the motor position and the ram position utilizing the isolated actuator parameter data sets.

15. The method of claim 9, wherein the method comprises substantially simultaneously collecting of the plurality of actuator parameter data sets, isolating of the various actuator data sets, and computing of the freeplay value of a plurality of actuators.

16. A system for monitoring the reliability status of a mobile platform actuator that controls movement of a control surface of the mobile platform, said system comprising:

a mobile platform computing system adapted to generate at least;

an actuator drive motor position signal comprising a plurality of motor position data indicative of a drive motor position during a predetermined data collection period as the drive motor is commanded to repeatedly drive an actuator output ram between an extending direction and a retracting direction;

a drive motor velocity signal comprising a plurality of motor velocity data indicative of the drive motor velocity during the data collection period, and

an actuator output ram position signal comprising a plurality of ram position data indicative of the actuator output ram position during the data collection period; and

an actuator freeplay monitor module operable in cooperation with the mobile platform computing system, the actuator freeplay monitor module adapted to;

collect a plurality of actuator parameter data sets during the data collection period, each actuator parameter data set comprising a motor position data value, a motor velocity data value and a ram position data value;

selectively isolate various sets of the plurality of actuator parameter data sets that include a motor position data value within a motor position range, a motor velocity data value within a motor velocity range and a ram position data value within a ram position range; and

generate an amount of freeplay value within the actuator for the data collection period based on the isolated actuator parameter data sets.

17. The system of claim 16, wherein to generate the motor position, the motor velocity and the ram position signals, the mobile platform computing system is further adapted to operate the drive motor to drive the actuator output ram in accordance with a wave form command that oscillates the drive motor operation between the extending and retracting directions.

18. The system of claim 16, wherein to collect the plurality of actuator parameter data sets, the actuator freeplay monitor module is further adapted to perform identical filtering on each of the motor position signal, the motor velocity signal and the ram position signal to remove noise from the motor position signal, the motor velocity signal and the ram position signal.

19. The system of claim 16, wherein to collect the plurality of actuator parameter data sets, the actuator freeplay monitor module is further adapted to normalize the motor position signal and the ram position signal.

20. The system of claim 16, wherein to compute an amount of freeplay value, the actuator freeplay monitor module is further adapted to calculate a mean value of the lag between the motor position and the ram position utilizing the isolated actuator parameter data sets.