Fault-tolerant electromechanical actuator having a torque sensing control system

• US 20060113933A1
• Filed: 12/01/2005
• Published: 06/01/2006
• Est. Priority Date: 06/04/2004
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Peck, James Leo, Blanding, David E.
• Granted Patent: US 7,834,494 B2
• Time in Patent Office: Days
• US Class Current: 318/116
• CPC Class Codes: B64C 13/00 Control systems or transmitting systems for actuating flying-control surfaces, lift-increasing flaps, air brakes, or spoilers
• CPC Class Codes: B64C 13/24 Transmitting means
• CPC Class Codes: F16H 2025/2071 Disconnecting drive source from the actuator, e.g. using clutches for release of drive connection during manual control
• CPC Class Codes: F16H 2025/2078 the rotor being integrated with the nut or screw body
• CPC Class Codes: F16H 25/2015 Means specially adapted for stopping actuators in the end position; Position sensing means
• CPC Class Codes: F16H 25/2025 with means to disengage the nut or screw from their counterpart; Means for connecting screw and nut for stopping reciprocating movement F16H25/2015 takes precedence
• CPC Class Codes: F16H 25/2252 Planetary rollers between nut and screw
• CPC Class Codes: H02K 11/24 Devices for sensing torque, or actuated thereby H02K11/27 takes precedence
• CPC Class Codes: H02K 11/27 Devices for sensing current, or actuated thereby overcurrent protection responsive to temperature of the machines or parts thereof, e.g. windings, H02K11/25
• CPC Class Codes: H02K 16/00 Machines with more than one rotor or stator machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029
• CPC Class Codes: H02K 7/06 Means for converting reciprocating motion into rotary motion or vice versa
• CPC Class Codes: H02K 7/108 with friction clutches
• CPC Class Codes: H02K 7/116 with gears
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y10T 74/186 Alternate power path operable on failure of primary

Abstract

An electromechanical actuator (EMA) is provided. The EMA includes a threaded output ram connectable to a mechanical component and at least one motor module engageable with the output ram for controllably translating the output ram along a linear axis of the output ram. The actuator further includes a torque sensing adaptive control (TSAC) system for monitoring torque within the motor module. The TSAC generates a disengagement command signal when the TSAC system determines torque within the motor module is outside an allowable motor module torque range. The disengagement command signal initiates disengagement of the motor module from the output ram.

Claims

1. An electromechanical actuator comprising:

at least one motor module engageable with an output ram for controllably translating the output ram along a linear axis of the output ram; and

a torque sensing adaptive control (TSAC) system for monitoring motor module torque within the motor module and generating a disengagement command signal to initiate disengagement of the motor module from the output ram when the torque within the motor module is outside an allowable motor module torque range.

2. The actuator of claim 1, wherein the motor module comprises a solenoid disengagement device operable in response to the disengage command signal to disengage the rollers from the output ram.

3. The actuator of claim 1, wherein the motor module comprises a micro-actuator disengagement device operable in response to the disengage command signal to disengage the rollers from the output ram.

4. The actuator of claim 3, wherein the micro-actuator disengagement device comprises a piezo-electric device.

5. The actuator of claim 1, wherein the TSAC system includes a torque sensing circuit for sensing operating parameters of the motor module.

6. The actuator of claim 5, wherein the TSAC system further includes a controller communicatively connected to the torque sensing circuit for analyzing the torque within the motor module and determining when the motor module torque is outside the allowable motor module torque range based on the motor module operating parameters sensed by the torque sensing circuit.

7. The actuator of claim 6, wherein the TSAC controller is adapted to analyze the torque within the motor module during a low frequency zone of motor module operation.

8. The actuator of claim 6, wherein the TSAC system further includes an actuator drive circuit communicatively connected to the TSAC controller, for activating a motor module disengagement actuation device upon receiving the motor disable command.

9. The actuator of claim 6, wherein the TSAC system further includes an electronic storage device for storing at least one torque monitoring algorithm executable by the TSAC controller to determine whether the motor module torque is outside the allowable motor module torque range.

10. The actuator of claim 5, wherein the roller nut comprises a segmented roller nut including a plurality of separable sections retained together by a pair of C-ring biasing devices.

11. The actuator of claim 1, wherein the actuator comprises:

a plurality of motor modules engageable with the output ram for controllably moving the output ram along a linear axis of the output ram; and

at least one TSAC system for monitoring torque within the motor modules and generating the disengagement command signal to initiate disengagement of any of the motor modules from the output ram when the torque within the respective motor module is outside an allowable motor module torque range.

12. An electromechanical actuator comprising:

a threaded output ram connectable to a mechanical component;

at least one motor module for controllably translating the output ram along a linear axis of the output ram to impart movement to the mechanical component; and

a torque sensing adaptive control (TSAC) system for monitoring torque within the motor module and determining whether the motor module torque is outside an allowable motor module torque range;

wherein the motor module comprises;

a roller nut having a plurality of threaded rollers engageable with the threaded output ram;

a disengaging cam for disengaging the threaded rollers from the threaded shaft; and

a disengagement actuation device for causing the disengaging cam to disengage the threaded rollers from the threaded shaft when the TSAC system determines the motor module torque is outside the allowable motor module torque range.

13. The actuator of claim 12, wherein the actuation device comprises a solenoid disengagement device activated by the disengage command signal to move the disengaging cam along the axis of the output ram to disengage the rollers from the output ram.

14. The actuator of claim 12, wherein the actuation device comprises a micro-actuator disengagement device activated by the disengage command signal to move the disengaging cam along the axis of the output ram to disengage the rollers from the output ram.

15. The actuator of claim 14, wherein the micro-actuator disengagement device comprises a piezo-electric device.

16. The actuator of claim 12, wherein the TSAC system includes a torque sensing circuit for sensing operating parameters of the motor module, the operating parameters including at least one of a motor module drive current, a linear position of the output ram along a longitudinal axis of the output ram, a rotational velocity of the roller nut and a voltage applied to the motor module.

17. The actuator of claim 16, wherein the TSAC system further includes a controller communicatively connected to the torque sensing circuit for analyzing the torque within the motor module and determining when the motor module torque is outside the allowable motor module torque range based on the motor module operating parameters sensed by the torque sensing circuit.

18. The actuator of claim 17, wherein the TSAC controller is adapted to analyze the torque within the motor module during a low frequency zone of motor module operation.

19. The actuator of claim 17, wherein the TSAC system further includes an actuator drive circuit communicatively connected to the TSAC controller, for activating the disengagement actuation device upon receiving a motor disable command generated by the TSAC controller when the TSAC controller determines the motor module torque is outside the allowable motor module torque range.

20. The actuator of claim 17, wherein the TSAC system further includes an electronic storage device for storing at least one torque monitoring algorithm executable by the TSAC controller to determine whether the motor module torque is outside the allowable motor module torque range based on the motor module operating parameters sensed by the torque sensing circuit.

21. The actuator of claim 12, wherein the roller nut comprises a segmented roller nut including a plurality of separable sections retained together by a pair of C-ring biasing devices.

22. The actuator of claim 12, wherein the actuator comprises:

a plurality of motor modules engageable with the output ram for controllably moving the output ram along a linear axis of the output ram; and

at least one TSAC system for monitoring torque within the motor modules and generating the disengagement command signal to initiate disengagement of any of the motor modules from the output ram when the TSAC system determines torque within the respective motor module is outside an allowable motor module torque range.

23. A mobile platform comprising:

a mechanical component coupled to a threaded output ram of an electromechanical actuator (EMA) such that movement of the mechanical component is controlled by linear translation of the output ram, wherein the EMA comprises;

at least one motor module for controllably translating the output ram along a linear axis of the output ram to impart movement to the mechanical component; and

a torque sensing adaptive control (TSAC) system for monitoring torque within the motor module and determining whether the motor module torque is outside an allowable motor module torque range;

wherein the motor module comprises;

a roller nut having a plurality of threaded rollers engageable with the threaded output ram;

a disengaging cam for disengaging the threaded rollers from the threaded shaft; and

a disengagement actuation device for causing the disengaging cam to disengage the threaded rollers from the threaded shaft when the TSAC system determines the motor module torque is outside the allowable motor module torque range.