Fail passive servo controller

• US 6,573,672 B2
• Filed: 06/29/2001
• Issued: 06/03/2003
• Est. Priority Date: 06/29/2001
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: O'Rourke, Kenneth, Wilkens, Dean, Beutler, Arthur D.
• Primary Examiner(s): Nappi; Robert E.
• Assistant Examiner(s): Duda; Rina I.
• Application Number:
  US09/896,218
• Publication Number:
  US 20030001530A1
• Time in Patent Office: 704 Days
• Field of Search: 318/254,563,564,705,706
• US Class Current: 318/400.21
• CPC Class Codes: G05D 1/0072 to counteract a motor failure
• CPC Class Codes: H02P 6/24 Arrangements for stopping

Abstract

The present invention provides apparatus, systems and methods for fail passive servo controllers. In accordance with an exemplary embodiment of the present invention, servo controller is used with an ALS to control an aircraft during landing procedures. In accordance with one aspect of this exemplary embodiment, upon a failure (e.g., of one of the components of ALS) servo controller fails passively rather than actively. In an exemplary embodiment, the fail passive nature of the servo unit is accomplished by providing at least two independent signal and drive current paths for controlling the servo motor. As such, the servo motor will not generate torque unless the two independent signal lanes agree. For example, when a component such as processor, difference amplifier, or PWM fails or otherwise ceases to function properly, servo motor will not runaway, but rather will fail with only minor transient movement, or alternatively, servo unit will lock at its current position. In this manner, servo motor will not generate a deviation from flight path or other significant control inputs until system monitors detect the fault and return control to the pilot.

Claims

1. A fail passive servo unit (100), comprising:

a servo input (102);

a motor (106); and

a motor controller (104), having at least two corresponding signal lanes (214), wherein said corresponding signal lanes (214) must have corresponding voltages for said motor (106) to commutate, and wherein when a component of the servo unit (100) fails, said signal lanes (214) will not agree and said motor controller 104) will direct power through said signal lanes (214) such that a voltage differential across said motor (106) is zero.

2. The fail passive servo unit (100) of claim 1, further comprising a motor position sensor (202.)

3. The fail passive servo unit (100) of claim 2, wherein said motor position sensor (202) comprises three motor position sensors.

4. The fail passive servo unit (100) of claim 3, wherein said three motor position sensors (202) comprise hall effect sensors.

5. The fail passive servo unit (100) of claim 2, wherein said motor position sensor (202) comprise a hall effect sensor.

6. The fail passive servo unit (100) of claim 1, wherein said signal lanes (214) each further comprise at least one switch (208).

7. The fail passive servo unit (100) of claim 6, wherein said at least one switch (208) comprises 6 field effect transistors.

8. The fail passive servo unit (100) of claim 6, wherein said at least one switch (208) comprises 12 field effect transistors.

9. The fail passive servo unit (100) of claim 1, wherein said motor (106) is a brushless DC motor.

10. The fail passive servo unit (100) of claim 9, wherein said brushless DC motor (106) has windings in a Y-configuration.

11. The fail passive servo unit (100) of claim 10, wherein said brushless DC motor (106) has windings in a Delta-configuration.

12. The fail passive servo unit (100) of claim 1, wherein said servo input (102) is an automatic landing system (ALS) signal.

13. An automated landing system (ALS) fail passive servo unit (100), comprising:

an ALS input (102);

a brushless DC motor (106); and

a motor controller (104), having at least two corresponding signal lanes (214), wherein said corresponding signal lanes (214) must agree for said motor (106) to commutate, each signal lane having at least one FET switch (208), wherein when a component of the servo unit (100) fails, said motor controller (104) directs power through said FET (208) in order to cause a voltage differential across said brushless DC motor (106) to be zero.

14. The ALS fail passive servo unit (100) of claim 13, further comprising at least one hall effect sensor (202) for detecting the position of said motor (106).

15. The ALS fail passive servo unit (100) of claim 14, wherein said hall effect sensor (202) comprises three hall effect sensors.

16. The ALS fail passive servo unit (100) of claim 13, wherein said at least one FET switch (208) comprises 6 FET switches.

17. The ALS fail passive servo unit (100) of claim 16, wherein said brushless DC motor (106) has windings in a Y-configuration.

18. The ALS fail passive servo unit (100) of claim 13, wherein said at least FET switch (208) comprises 12 FET switches.

19. The ALS fail passive servo unit (100) of claim 18, wherein said brushless DC motor (106) has windings in a Delta-configuration.

20. A fail passive servo unit (100), comprising:

a servo input (102);

a motor (106);

a motor output (108); and

a motor controller (104), having means for causing a voltage differential across said motor (106) to be zero when a component of the servo unit (100) fails, said means comprising at least two corresponding signal lanes (214), wherein said corresponding signal lanes (214) must have corresponding voltages for said motor (106) to commutate, and wherein when a component of the servo unit (100) fails, said signal lanes (214) will not agree and said motor controller (104) will direct power through said signal lanes (214) such that a voltage differential across said motor (106) is zero.

21. The fail passive servo unit (100) of claim 20, further comprising means for determining the position of motor (106).

22. The fail passive servo unit (100) of claim 21, wherein said means for determining the position of motor (106) comprises a hall effect sensor (202).

23. The fail passive servo unit (100) of claim 21, wherein said means for determining the position of motor (106) comprises three motor position sensors (202).

24. The fail passive servo unit (100) of claim 22, wherein said three motor position sensors (202) are hall effect sensors.

25. The fail passive servo unit (100) of claim 21, wherein said means for causing a voltage differential across said motor (106) comprises a field affect transistor (208).

26. A fail passive servo unit (100) of claim 21, wherein said means for causing a voltage differential across said motor (106) comprises 6 switches (208).

27. The fail passive servo unit (100) of claim 26, wherein said 6 switches (208) comprise field effect transistors.

28. The fail passive servo unit (100) of claim 20, wherein said means for causing a voltage differential across said motor (106) comprises 12 switches (208).

29. The fail passive servo unit (100) of claim 28, wherein said 12 switches (208) comprise field effect transistors.

30. The fail passive servo unit (100) of claim 20, wherein said motor (106) is a brushless DC motor.

31. The fail passive servo unit (100) of claim 30, wherein said brushless DC motor (106) has windings in a Y-configuration.

32. The fail passive servo unit (100) of claim 30, wherein said brushless DC motor (106) has windings in a Delta-configuration.