Rotorcraft autopilot control

• US 9,868,522 B2
• Filed: 08/21/2014
• Issued: 01/16/2018
• Est. Priority Date: 08/21/2014
• Status: Active Grant

• Current Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Original Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Inventors: Griffith, Carl D., Atkins, Brady G., Raza, Awais, Wilson, Paul M.
• Primary Examiner(s): REPHANN, JUSTIN B
• Application Number:
  US14/465,334
• Publication Number:
  US 20160052628A1
• Time in Patent Office: 1,244 Days
• CPC Class Codes: B64C 13/0421 control sticks for primary flight controls
• CPC Class Codes: B64C 13/0427 for actuating trim
• CPC Class Codes: B64C 13/044 operated by feet, e.g. pedals
• CPC Class Codes: B64C 13/18 using automatic pilot
• CPC Class Codes: B64C 13/341 having duplication or stand-by provisions
• CPC Class Codes: B64C 13/343 overriding of personal controls; with automatic return to inoperative position
• CPC Class Codes: B64C 13/345 with artificial feel
• CPC Class Codes: B64C 27/04 Helicopters
• CPC Class Codes: B64C 27/56 characterised by the control initiating means, e.g. manually actuated
• CPC Class Codes: B64C 27/57 automatic or condition responsive, e.g. responsive to rotor speed, torque or thrust
• CPC Class Codes: B64C 27/58 Transmitting means, e.g. interrelated with initiating means or means acting on blades means acting on blades B64C27/72

Abstract

A rotorcraft autopilot system includes a series actuator connecting a cockpit control component to a swashplate of a rotorcraft, the series actuator to modify a control input from the cockpit control component to the swashplate through a downstream control component. The rotorcraft autopilot system also includes a differential friction system connected to the cockpit control component, the differential friction system to control the series actuator to automatically adjust a position of the cockpit control component during rotorcraft flight based, in part, on a flight mode of the rotorcraft.

Claims

1. A rotorcraft autopilot system, comprising:

a series actuator connecting a cockpit control component to a swashplate of a rotorcraft, the series actuator to modify a control input from the cockpit control component to the swashplate through a downstream control component;

a differential friction system connected to the cockpit control component and the downstream control component, the differential friction system comprising a variable friction device grounded to the rotorcraft proximate the downstream control component, the variable friction device configured to increase or decrease a friction on the downstream control component; and

wherein the differential friction system is configured to selectively apply the friction on the downstream component to control the series actuator to automatically adjust a position of the cockpit control component during rotorcraft flight based, in part, on a flight mode of the rotorcraft.

2. The rotorcraft autopilot system of claim 1, wherein the series actuator modifies the control input by adjusting a movement between an upstream control component connected to the cockpit control component and the downstream control component to move the swashplate in response to the control input from the cockpit control component.

3. The rotorcraft autopilot system of claim 2, wherein the upstream control component and the downstream control component comprise an upstream control linkage and a downstream control linkage, respectively.

4. The rotorcraft autopilot system of claim 2, wherein the differential friction system comprises a clutch brake grounded to the rotorcraft proximate the upstream control component, the clutch brake to engage or disengage the upstream control component.

5. The rotorcraft autopilot system of claim 4, wherein the clutch brake is a magnetic clutch brake.

6. The rotorcraft autopilot system of claim 4, wherein, when the clutch brake is disengaged, a fixed friction of the downstream control component substantially prevents the downstream control component from movement.

7. The rotorcraft autopilot system of claim 4, further comprising a centering spring on the upstream control component between the clutch brake and the cockpit control component, the centering spring to bias the cockpit control component toward a neutral center position when the clutch brake is engaged.

8. A method, comprising:

determining a flight mode of a rotorcraft;

identifying a swashplate position of the rotorcraft corresponding to the determined flight mode; and

applying a friction on a downstream control component connecting a series actuator to the swashplate to substantially prevent a movement of the downstream control component such that a cockpit control position of a rotorcraft cockpit control component connected to the series actuator by an upstream control component is adjusted by a differential friction across the series actuator.

9. The method of claim 8, further comprising adjusting the differential friction across the series actuator to cause the series actuator to adjust the cockpit control component or the swashplate.

10. The method of claim 9, wherein adjusting the differential friction across the series actuator to cause the series actuator to adjust the cockpit control component comprises:

disengaging a clutch brake on the upstream control component to allow movement of the upstream control component, wherein the clutch brake grounded is to the rotorcraft proximate the upstream control component; and

increasing the friction of a variable friction device on the downstream control component connecting the series actuator to the swashplate to substantially prevent movement of the downstream control component.

11. The method of claim 10, wherein adjusting the differential friction across the series actuator to cause the series actuator to adjust the cockpit control component further comprises:

centering the series actuator to move the upstream control component; and

adjusting the cockpit control position to match the identified swashplate position.

12. The method of claim 10, wherein adjusting the differential friction across the series actuator to cause the series actuator to adjust the cockpit control component comprises intermittently decreasing friction of the variable friction device on the downstream control component to allow movement of the downstream control component.

13. The method of claim 12, further comprising engaging the clutch brake on the upstream control component to substantially prevent movement of the upstream control component while decreasing friction of the variable friction device on the downstream control component.

14. The method of claim 8, wherein the flight mode of the rotorcraft is a hover mode;

and

wherein the adjusted cockpit control position of the cockpit control component is a centered position.

15. A method for controlling rotorcraft flight, the method comprising:

providing a variable friction device connected to a downstream linkage, a series actuator connected to the variable friction device, and an upstream linkage connected to the series actuator;

adjusting a differential friction between the upstream linkage and the downstream linkage relative to the series actuator using the variable friction device to allow movement of the upstream linkage and prevent movement of the downstream linkage; and

controlling actuation of the series actuator in response to the adjusted differential friction between the upstream linkage and the downstream linkage.

16. The method of claim 15, wherein adjusting the differential friction between the upstream linkage and the downstream linkage relative to a series actuator comprises applying a first, higher friction on the downstream linkage than a second, lower friction on the upstream linkage.

17. The method of claim 15, wherein controlling actuation of the series actuator in response to the adjusted differential friction between the upstream linkage and the downstream linkage comprises:

centering the series actuator; and

moving the upstream linkage to position a cockpit control stick connected to the upstream linkage.

18. The method of claim 17, further comprising:

determining a cockpit control stick position corresponding to a swashplate position in a flight mode of the rotorcraft, the downstream linkage connected to the swashplate; and

positioning the cockpit control stick in the determined cockpit control stick position.