Autopilot system for a helicopter

• US 20060100751A1
• Filed: 10/11/2005
• Published: 05/11/2006
• Est. Priority Date: 10/08/2004
• Status: Active Grant

• Current Assignee: Airbus Helicopters
• Original Assignee: Euroopter
• Inventors: Saleese-Lavergne, Marc
• Granted Patent: US 7,558,653 B2
• Time in Patent Office: Days
• US Class Current: 701/11
• CPC Class Codes: G05D 1/102 specially adapted for vertical take-off of aircraft

Abstract

The present invention relates to an autopilot system for a rotary wing aircraft operating relative to at least two pilot axes, which system comprises, for each of the two axes, at least one servo-control relationship providing a respective initial control instruction, with the two relationships having a common target; the system includes combination means (36) for providing a series of control instructions by combining the two initial control instructions (UCV, UTV).

Claims

1. An autopilot system (11) for a rotary wing aircraft having at least two pilot axes,.the system comprising for each of the two axes at least one servo-control relationship module (31, 32) supplying a respective initial control instruction (UCV, UTV), the two relationships having a common target, the system including calculation and combination means (36, 37, 39) for calculating control instructions (UICOLL, UTMIN) by combining the two initial control instructions (UCV, UTV).

2. A system according to claim 1, in which the combination is a linear combination of the two initial control instructions (UCV, UTV) and of their ratios (UCV/UTV, UTV/UCV).

3. A system according to claim 1, in which the two pilot axes are a tilt axis and a collective axis, and in which the servo-control relationships of the modules (31, 32) delivering the initial control instructions are, for each of these axes, vertical-target relationships.

4. A system according to claim 1, including selector and corrector means (41) for selecting two control instructions from a series of possible control instructions obtained by combining the initial control instructions, and for correcting the selected control instructions, where appropriate.

5. A system according to claim 4, in which the selector means comprise a servo-control module (34) for applying a relationship for maintaining an absorbed power for driving the rotor at a value below a setpoint value.

6. A system according to claim 5, in which the relationship (34) for maintaining power takes priority over the other servo-control relationships (31, 32, 33, 35) of the autopilot system.

7. A system according to claim 4, in which the selector means comprise a servo-control module (33) applying a relationship for maintaining aircraft forward speed of the aircraft above a setpoint value.

8. A system according to claim 4, in which the selector means comprise a servo-control module (35) applying a relationship for maintaining aircraft air speed above a predetermined value corresponding to the optimum speed for climbing.

9. A system according to claim 1, in which the corrector means comprise a module (40) for limiting the collective pitch control instruction (UCOLL) as a function of a power-maintaining instruction (UCP).

10. A system according to claim 1, including a module (37) for calculating an intermediate tilt instruction (UTMIN) as a function of a power-maintaining instruction (UCP).

11. A system according to claim 10, including a module (38) for comparing the intermediate tilt instruction (UTMIN), a tilt instruction (UTL) having a forward-advance target, and a tilt instruction (UTY) having a vertical air speed target, and for selecting the final tilt instruction (UTILT) from amongst those three instructions.

12. A system according to claim 1, comprising a module (39) for calculating an intermediate collective pitch instruction (UICOLL) as a function of a tilt instruction (UTILT).

13. An autopilot system (11) for a rotary wing aircraft operating relative to a tilt axis and a collective pitch axis, the system comprising:

a first servo-control module (31) for applying a first relationship to supply an initial collective pitch control instruction (UCV); and

a second servo-control module (32) for applying a second relationship supplying an initial tilt control instruction (UTV);

the first and second relationships having a common target, the system further comprising;

calculation and combination means (36, 37, 39) for calculating intermediate control instructions (UICOLL, UTMIN) by combining the two initial control instructions (UCV, UTV);

a third servo-control module (33, 34, 35) applying a third relationship providing a third control instruction (UTL, UCP, UTY) for tilt or for collective pitch, the third relationship having a target that is different from said common target; and

selector and corrector means (41) for selecting two control instructions from the intermediate control instructions, and where appropriate for correcting the selected control instructions, as a function of the third control instruction.

14. A system according to claim 13, in which the combination is a linear combination of the two initial control instructions (UCV, UTV) and of their ratios (UCV/UTV, UTV/UCV).

15. A system according to claim 13, in which the servo-control relationships of the modules (31, 32) issuing the initial control instructions are, for each of these axes, vertical-target relationships.

16. A system according to claim 13, in which the selector means comprise a servo-control module (34) applying a relationship for maintaining power absorbed for driving the rotor to a value below a setpoint value, and in which the relationship (34) for maintaining power has priority over the other servo-control relationships (31, 32, 33, 35) of the autopilot system.

17. A system according to claim 13, in which the selector means comprise a servo-control module (33) for applying a relationship for maintaining aircraft speed of advance above a setpoint value.

18. A system according to claim 13, in which the selector means comprise a servo-control module (35) for applying a relationship for maintaining aircraft air speed above a predetermined value corresponding to the optimum speed for climbing.

19. A system according to claim 13, in which the corrector means comprise a module (40) for limiting the collective pitch control instruction (UCOLL) as a function of a power maintaining instruction (UCP).

20. A system according to claim 13, comprising:

a module (37) for calculating an intermediate tilt instruction (UTMIN) as a function of a power-maintaining instruction (UCP);

a module (38) for comparing the intermediate tilt instruction (UTMIN) with a tilt instruction having a forward-advance target (UTL) and with a tilt instruction having a vertical air speed target (UTY), and for selecting a final tilt instruction (UTILT) from amongst these three instructions; and

a module (39) for calculating an intermediate collective pitch instruction (UICOLL) as a function of the final tilt instruction (UTILT).