SYSTEMS AND METHODS FOR DETECTING SOLENOID ARMATURE MOVEMENT

• US 20110149458A1
• Filed: 12/17/2009
• Published: 06/23/2011
• Est. Priority Date: 12/17/2009
• Status: Abandoned Application

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Schumacher, Joseph W., Love, William J., Thomas, Philip J.
• Application Number:
  US12/640,372
• Publication Number:
  US 20110149458A1
• Time in Patent Office: Days
• US Class Current: 361/160
• CPC Class Codes: H01F 7/1844 Monitoring or fail-safe circuits for relays H01H47/002

Abstract

A method for detecting actuation of an armature associated with a solenoid includes providing a voltage potential to a solenoid coil associated with the solenoid. The method also includes measuring a current flowing through the solenoid coil. The method further includes switching the voltage potential off when the measured current reaches a predetermined maximum value. The method also includes switching the voltage potential on when the measured current reaches a predetermined minimum value. The method further includes measuring a chop period between pulses associated with the switching on and off of the voltage potential. The method also includes analyzing successive chop periods to detect armature movement and armature seating. The method further includes determining, based on the comparison of chop periods, a pull-in time of an armature associated with the solenoid.

Claims

1. A method for detecting actuation of an armature associated with a solenoid, comprising:

providing a voltage potential to a solenoid coil associated with the solenoid and substantially concurrently starting a start of current timer;

measuring a current flowing through the solenoid coil;

switching the voltage potential off when the measured current reaches a predetermined maximum value;

switching the voltage potential on when the measured current reaches a predetermined minimum value;

measuring a chop period associated with the switching off and switching on of the voltage potential;

analyzing successive chop periods to detect armature movement and armature seating; and

determining armature movement and armature seating times based on the analysis.

2. The method of claim 1, wherein the analyzing step includes logging successive data points on a graph where time from the start of current is measured on the x-axis, and chop period is measured on the y-axis.

3. The method of claim 2, wherein the analyzing step further includes comparing the value of successive chop periods to one another.

4. The method of claim 3, wherein the determination step further includes identifying movement of the armature as a point in time wherein the value of a succeeding chop period is less than or equal to an immediately preceding chop period.

5. The method of claim 3, wherein the determination step further includes determining a pull-in time as a time wherein the value of the chop period is at its absolute maximum.

6. The method of claim 1, wherein measuring the chop period measures the time between switching the voltage potential on and switching the voltage potential off.

7. The method of claim 1, wherein measuring the chop period measures the time elapsed between switching the voltage potential off and switching the voltage potential on.

8. The method of claim 1, wherein measuring the chop period measures the time elapsed between switching the voltage potential on, switching the voltage potential off, and switching the voltage potential back on again.

9. The method of claim 1, wherein measuring the chop period measures the time elapsed between switching the voltage potential off, switching voltage potential on, and switching the voltage potential back off again.

10. An armature actuation detection system, comprising:

a power supply selectively coupled to a solenoid coil via one or more switching elements and configured to provide a voltage output;

a controller operatively coupled to the one or more switching elements and configured to;

operate the one or more switching elements to selectively provide a voltage potential to the solenoid coil and substantially concurrently start a start of current timer;

measure a current flowing through the solenoid coil;

switch the voltage potential off when the measured current reaches a predetermined maximum value;

switch the voltage potential on when the measured current reaches a predetermined minimum value;

measure a chop period between pulses of the voltage potential;

analyze successive chop periods to detect armature movement and armature seating; and

determine armature movement and armature seating times based on the analysis.

11. The system of claim 10, wherein the controller includes an electronic control unit associated with a machine.

12. The system of claim 10, wherein the analysis of successive chop periods further includes logging successive data points on a graph where time from the start of current is measured on the x-axis, and chop period is measured on the y-axis.

13. The system of claim 12, wherein the analysis of successive chop periods further includes comparing the value of successive chop periods to one another

14. The system of claim 13, wherein the analysis of successive chop periods further includes identifying movement of the armature as a point in time wherein the value of a succeeding chop period is less than or equal to an immediately preceding chop period.

15. The system of claim 13, wherein the determination of armature movement further includes determining a pull-in time as a time wherein the value of the chop period is at its absolute maximum.

16. The system of claim 10, wherein the controller is further configured to measure the chop period between pulses as a time between switching the voltage potential off and switching the voltage potential on.

17. The system of claim 10, wherein measuring the chop period measures the time between switching the voltage potential off and switching the voltage potential on.

18. The system of claim 10, wherein the controller is further configured to measure the chop period between pulses as a time elapsed between switching the voltage potential on, switching the voltage potential off, and switching the voltage potential back on again.

19. The system of claim 10, wherein the controller is further configured to measure the chop period between pulses as a time elapsed between switching the voltage potential off, switching the voltage potential on, and switching the voltage potential back off again.

20. A machine, comprising:

a solenoid having a conductor and an armature, wherein the conductor is coiled substantially around the armature in a longitudinal direction and separated from the armature via an air gap, the armature being adapted to move relative to the conductor in the presence of an electromagnetic field generated by the conductor;

an armature actuation detection system operatively coupled to the solenoid, the armature actuation detection system including;

a power supply selectively coupled to a solenoid conductor via one or more switching elements and configured to provide a voltage output;

a controller operatively coupled to the one or more switching elements and configured to;

operate the one or more switching elements to selectively provide a voltage potential to the solenoid conductor and substantially concurrently start a start of current timer;

measure a current flowing through the solenoid conductor;

switch the voltage potential off when the measured current reaches a predetermined maximum value;

switch the voltage potential on when the measured current reaches a predetermined minimum value;

measure a chop period between pulses of the voltage potential;

analyze successive chop periods to detect armature movement and armature seating; and

determine armature movement and armature seating times based on the analysis.

21. The machine of claim 20, wherein the controller includes an electronic control system associated with a machine.

22. The machine of claim 20, wherein the analysis of successive chop periods further includes logging successive data points on a graph where time from the start of current is measured on the x-axis, and chop period is measured on the y-axis.

23. The machine of claim 21, wherein the analysis of successive chop periods further includes comparing the value of successive chop periods to one another

24. The machine of claim 22, wherein the analysis of successive chop periods further includes identifying movement of the armature as a point in time wherein the value of a succeeding chop period is less than or equal to an immediately preceding chop period.

25. The machine of claim 22, wherein the determination of armature movement further includes determining a pull-in time as a time wherein the value of the chop period is at its absolute maximum.

26. The machine of claim 20, wherein the controller is further configured to measure the chop period between pulses as a time elapsed switching the voltage potential off and switching the voltage potential on.

27. The machine of claim 20, wherein measuring the chop period measures the time elapsed between switching the voltage potential off and switching the voltage potential on.

28. The machine of claim 20, wherein the controller is further configured to measure the chop period between pulses as a time elapsed between switching the voltage potential on, switching the voltage potential off, and switching the voltage potential back on again.

29. The machine of claim 20, wherein the controller is further configured to measure the chop period between pulses as a time elapsed between switching the voltage potential off, switching the voltage potential on, and switching the voltage potential back off again.