Rotorcraft control system

• US 8,170,728 B2
• Filed: 05/15/2008
• Issued: 05/01/2012
• Est. Priority Date: 05/22/2007
• Status: Active Grant

• Current Assignee: Airbus Helicopters
• Original Assignee: Eurocopter
• Inventors: Roesch, Philippe
• Primary Examiner(s): Algahaim, Helal A
• Application Number:
  US12/120,662
• Publication Number:
  US 20080294305A1
• Time in Patent Office: 1,447 Days
• Field of Search: 701/3, 701/7, 244/6, 244/8, 244/34.R
• US Class Current: 701/3
• CPC Class Codes: B64C 27/22 Compound rotorcraft, i.e. aircraft using in flight the features of both aeroplane and rotorcraft
• CPC Class Codes: G05D 1/0858 specially adapted for vertical take-off of aircraft

Abstract

A system (100) for controlling a rotorcraft (1) including a rotor (10), at least one variable-pitch propulsion propeller (6L, 6R), and a motor (5) for driving the rotor and the propeller(s), the system includes:

• • a member (101, 101A, 102, 103, 104) for generating a propeller pitch setpoint (θ_p*+θ_d*, θ_p*−θ_d*) as a function at least of a thrust variation command (TCL);
  • a member (105, 105A) for generating a setpoint (RPM*) for the drive speed (RPM) of the rotor and the propeller(s), as a function at least of the travel speed (VTAS) of the rotorcraft; and
  • a member (106) for generating a setpoint (NG*) for the engine speed as a function at least of the thrust command (TCL), of the drive speed setpoint (RTM*), and of a rotor collective pitch command (θ₀).

Claims

1. A system for controlling a rotorcraft having a rotor, at least one variable-pitch propulsion propeller, and a motor for driving the rotor and the at least one variable-pitch propulsion propeller, the system comprising:

a member (101, 101A, 102, 103, 104) configured to generate a propeller pitch setpoint (θ

_p*+θ

_d*, θ

_p*−

θ

_d*) as a function at least of a variation thrust command (TCL);

a member (105, 105A) configured to generate a drive speed setpoint (RPM*) for a drive speed (RPM) of the rotor and the at least one variable-pitch propulsion propeller, as a function at least of a travel speed (VTAS) of the rotorcraft and where appropriate as a function of ambient temperature; and

a member (106) configured to generate an engine speed setpoint (NG*) for an engine speed as a function at least of the variation thrust command (TCL), of the drive speed setpoint (RPM*), and of a rotor collective pitch command (θ

₀);

wherein the member (106) configured to generate the engine speed setpoint (NG*) includes;

a member (109) configured to generate a first anticipated command for varying engine speed as a function of the rotor collective pitch command (θ

₀);

a member (110) configured to generate a second anticipated command for varying engine speed as a function of the variation thrust command (TCL);

a first summing circuit (111) for adding together the first and second anticipated commands for varying engine speed, and for outputting a first component (NG1*) of the engine speed setpoint (NG*); and

a unit (112, 113, 114) configured to generate the engine speed setpoint (NG*) as a function of the first component (NG1*), of the drive speed setpoint (RPM*), and of a measurement of the drive speed (RPM).

2. The system according to claim 1, in which the member (105, 105A) configured to generate the drive speed setpoint (RPM*) for the drive speed (RPM) comprises:

a member (107) configured to generate a reference drive speed (RPMref) as a function of the travel speed (VTAS) of the rotorcraft; and

a limiter (108) sensitive to the reference drive speed (RPMref) and delivering the drive speed setpoint (RPM*).

3. The system according to claim 1, for a rotorcraft having two variable-pitch propulsion propellers that are disposed on either side of the fuselage of the rotorcraft, the system comprising:

a member (101, 101A) configured to generate a mean pitch setpoint (θ

_p*) for the mean pitch (θ

_p) of the two variable-pitch propulsion propellers as a function of the variation thrust command (TCL);

a member (102) configured to generate a pitch difference setpoint (θ

_d*) for half the difference in pitch (θ

_d) between the two variable-pitch propulsion propellers as a function of the rotor collective pitch variation command (θ

₀) and of a heading/yaw variation command (Pal);

a summing circuit (103) for adding together the mean pitch setpoint (θ

_p*) and the pitch difference setpoint (θ

_d*), and for delivering the resulting setpoint (θ

_p*+θ

_d*) to a member for controlling the pitch of a first one of the two propellers; and

a summing circuit used as a subtracter (104) for subtracting the pitch difference setpoint (θ

_d*) from the mean pitch setpoint (θ

_p*) and for delivering the resulting setpoint (θ

_p*−

θ

_d*) to a pitch control member of the second propeller.

4. The system according to claim 3, in which the member (102) configured to generate a pitch difference setpoint (θ

_d*) for half the pitch difference comprises;

a decoupling unit (141) for collective-yaw decoupling, which decoupling unit receives the rotor collective pitch variation command (θ

₀);

a processor unit (142) for processing a heading variation command (Pal);

a summing circuit (143) connected to the decoupling unit and to the processor unit; and

a lowpass filter (144) receiving as input the sum delivered by the summing circuit and delivering as output the pitch difference setpoint (θ

_d*) for half the pitch difference.

5. The system according to claim 2, in which the member (105) configured to generate the drive speed setpoint (RPM*) for the drive speed (RPM) further comprises:

a member (115) configured to generate a transient variation (RPMper) in the drive speed setpoint (RPM*) as a function of the variation thrust command (TCL); and

a summing circuit (116) for adding the transient variation (RPMper) for the drive speed setpoint (RPM*) to the reference drive speed (RPMref) and for delivering said sum to the limiter (108) that delivers the drive speed setpoint (RPM*).

8. A rotorcraft including a rotor, at least one variable-pitch propulsion propeller, and a motor for driving the rotor and the at least one variable-pitch propulsion propeller, the rotorcraft including the control system according to claim 1.

9. The rotorcraft according to claim 8, including two variable-pitch propulsion propellers that are disposed on either side of the fuselage of the rotorcraft, which rotorcraft does not have an anti-torque rotor and does include a direct driving power transmission system between the engine and the rotor and the propellers.

6. A non-transitory computer readable medium for a rotorcraft having a rotor, at least one variable-pitch propulsion propeller, and a motor for driving the rotor and the at least one variable-pitch propulsion propeller, the non-transitory computer readable medium comprising:

a code segment for generating a propeller pitch setpoint (θ

_p*+θ

_d*, θ

_p*−

θ

_d*) as a function at least of a thrust variation command (TCL);

a code segment for generating a drive speed setpoint (RPM*) for a drive speed (RPM) of the rotor and of the at least one variable-pitch propulsion propeller, as a function at least of a travel speed (VTAS) of the rotorcraft; and

a code segment for generating an engine speed setpoint (NG*) for an engine speed, as a function at least of the variation thrust command (TCL), of the drive speed setpoint (RPM*), and of a rotor collective pitch command (θ

₀);

wherein the code segment for generating the engine speed setpoint (NG*) includes;

a code segment for generating a first anticipated command for varying engine speed as a function of the rotor collective pitch command (θ

₀);

a code segment for generating a second anticipated command for varying engine speed as a function of the variation thrust command (TCL);

a code segment for adding together the first and second anticipated commands for varying engine speed, and for outputting a first component (NG1*) of the engine speed setpoint (NG*); and

a code segment for generating the engine speed setpoint (NG*) as a function of the first component (NG1*), of the drive speed setpoint (RPM*), and of a measurement of the drive speed (RPM).

7. The non-transitory computer readable medium according to claim 6, in which the code segment for generating the drive speed setpoint (RPM*) for the drive speed (RPM) comprises a code segment for generating a reference drive speed (RPMref) that decreases as a function of the travel speed (VTAS) of the rotorcraft when the travel speed VTAS exceeds a determined speed V1.

10. A system for controlling a rotorcraft having a rotor, at least one variable-pitch propulsion propeller, and a motor for driving the rotor and the at least one variable-pitch propulsion propeller, the system comprising:

a member (101, 101A, 102, 103, 104) configured to generate a propeller pitch setpoint (θ

_p*+θ

_d*, θ

_p*−

θ

_d*) as a function at least of a variation thrust command (TCL);

a member (105, 105A) configured to generate a drive speed setpoint (RPM*) for a drive speed (RPM) of the rotor and the at least one variable-pitch propulsion propeller, as a function at least of a travel speed (VTAS) of the rotorcraft and where appropriate as a function of ambient temperature; and

a member (106) configured to generate an engine speed setpoint (NG*) for an engine speed as a function at least of the variation thrust command (TCL), of the drive speed setpoint (RPM*), and of a rotor collective pitch command (θ

₀);

wherein the member (105, 105A) configured to generate the drive speed setpoint (RPM*) for the drive speed (RPM) includes;

a member (107) configured to generate a reference drive speed (RPMref) as a function of the travel speed (VTAS) of the rotorcraft;

a limiter (108) sensitive to the reference drive speed (RPMref) and delivering the drive speed setpoint (RPM*);

a member (115) configured to generate a transient variation (RPMper) in the drive speed setpoint (RPM*) as a function of the variation thrust command (TCL); and

a summing circuit (116) for adding the transient variation (RPMper) for the drive speed setpoint (RPM*) to the reference drive speed (RPMref) and for delivering said sum to the limiter (108) that delivers the drive speed setpoint (RPM*).