Method and system for controlling the elevator assemblies of an aircraft

• US 4,765,568 A
• Filed: 09/09/1987
• Issued: 08/23/1988
• Est. Priority Date: 09/12/1986
• Status: Expired due to Fees

• Current Assignee: Messerschmitt-Boelkow-Blohm GmbH (Mercedes-Benz Group AG)
• Original Assignee: Messerschmitt-Boelkow-Blohm GmbH (Mercedes-Benz Group AG)
• Inventors: Dilmaghani, Homayoun, Carl, Udo
• Primary Examiner(s): Barefoot, Galen
• Assistant Examiner(s): Corl, Rodney
• Application Number:
  US07/094,831
• Time in Patent Office: 349 Days
• Field of Search: 244/75 R, 244/76 R, 244/87, 244/89, 244/221, 244/227, 244/228, 244/197
• US Class Current: 244/197
• CPC Class Codes: B64C 13/504 using electro-hydrostatic actuators [EHA's]
• CPC Class Codes: B64C 13/505 having duplication or stand-by provisions
• CPC Class Codes: G05D 1/0077 using redundant signals or controls
• CPC Class Codes: Y02T 50/40 Weight reduction

Abstract

A fly-by-wire control system for the elevator assemblies of an aircraft isquipped with a mechanical auxiliary control (8) and with a synchronizing coupling (10). The electrical control links connecting the controlling computers to the elevator drives are each equipped with an override mechanism (4,2). A mechanical cable link (9) of the auxiliary mechanical control (8) connects a pilot operated mechanical control member such as a pitch control wheel having a detent to the respective override mechanism. This combination makes sure that the pilot initiated control signals have performance priority over any other signals at all times. The synchronizing coupling (10) is arranged between the mechanical control links leading to the respective elevator flap drives to assure a symmetric flap deflection on both sides at high speed flight under failure conditions. Centering springs (12) assure a centered position of the flap if the respective flap side signal transmission linkage (4.4) is affected by a mechanical failure (rupture) at low speed.

Claims

1. A method for controlling elevator assemblies of an aircraft, comprising the following steps:

(a) normally supplying identical electrical flight control signals in parallel through two electrical control units each including an override mechanism arranged in series between each electrical control unit and respective mechanical control links to a plurality of drive means for each of said elevator assemblies,

(b) supplying, in an emergency, mechanically generated control signals through dual mechanical control links to each of said override mechanisms,

(c) providing with the aid of said override mechanism, a performance priority of said mechanically generated control signals for controlling and operating said elevator assemblies in an emergency, and

(d) mechanically coupling said mechanical control links by a mechanical synchronizing device at least during high speed flight for assuring a symmetric flap deflection of said elevator assemblies.

2. A system for controlling elevator assemblies of an aircraft, comprising fly-by-wire control means including pilot activated mechanical auxiliary control means, autopilot and flight control computer means, two electrically controlled control units (4) connected to said computer means, right and left elevator flaps (RH1, RL1), respective drive means (2) connected to said right and left elevator flaps, mechanical connecting links (3) between said drive means and said electrically controlled control units, means for normally synchronously (simultaneously) supplying elevator flap control signals from said computer means to said two electrically controlled control units (4) operating in parallel to each other, each of said electrically controlled control units (4) comprising a first section with electro-motors and gear drives and a second section with an override mechanism (4.2) for allocating a first priority to a mechanical emergency control signal generated by said auxiliary control means when a failure occurs in the electrical control, means for providing each active flight control computer means with information regarding instantaneous elevator flap controlled positions as determined by outputs of said two electrically controlled control units, whereby the flight control computer means recognize a non-operating control unit or an asynchronously operating control unit, whereupon faulty components are either switched-off or a switch-over is performed by the control computer means, said pilot activated mechanical auxiliary control means comprising a mechanical emergency control member enabling the pilot to respond to a system failure by providing a mechanical control signal for the control of the elevator assemblies, dual mechanical cable connections between each of said override mechanisms and said auxiliary control means for transmitting a mechanical control signal to each of the two override mechanisms in response to an operation of the emergency control member by the pilot for overriding any electrical control signal, wherein during electrical control, when said auxiliary control means is not activated, electrical elevator control signals cause a follow-up movement of the auxiliary control means synchronously and proportionally to the electrical control signals in response to a respective feedback command, wherein said mechanical emergency control member comprise a pitch control member with a detent for assuring an emergency control through one control cable link even if the other cable control link of said dual mechanical cable connections should be jammed, said pitch control member with its detent being so constructed that during a normal electrical control the generation of higher priority failure signals are prevented and the above mentioned first performance priority of the mechanical control signal is assured if said electrically controlled control means are supplying identical control signals to the mechanical control links leading to the elevator flap drives and to the emergency control member, and a mechanical synchronizing or coupling unit operatively arranged between the mechanical coupling links leading from the two electrically controlled control means to the respective elevator drive means (2) for assuring a synchronization of the elevator drive systems even when the mechanical emergency control is effective at high speed flight.

3. The system of claim 2, wherein said mechanical emergency control means comprise a mechanical double control member, such as duplicated control wheels with a release detent mechanism 8.1 between these wheels for operating said cable links provided in duplicate between said mechanical emergency control means and said override mechanism.

4. The system of claim 2, wherein said mechanical control linkage means between said elevator drive systems and said electrically controlled control means have a partly fail-safe construction, and wherein said mechanical synchronizing or coupling unit is connected to both mechanical control linkage means so as to be effective even when said mechanical emergency control is effective at high speed flight.

5. The system of claim 2, wherein said electrically controlled control means comprise electric motor means which are controlled by one or more flight computers of a single type or of different types.

6. The system of claim 5, wherein said electric motor means comprise at least two electric motors in each of said electrically controlled control means.

7. The system of claim 2, further comprising testing switch means (11) arranged for testing the operability of said mechanical emergency control means.

8. The system of claim 2, wherein, under normal flight conditions, said electrically controlled control means entrain said mechanical emergency control means, whereby said mechanical emergency control means perform a follow-up movement thereby indicating to the pilot that said mechanical emergency control means are free of any jamming.

9. The system of claim 2, further comprising centering springs (12) provided in said mechanical connecting links (3) for preventing an uncontrolled deflection of an elevator flap if the respective mechanical transmission link (4.4) should fail.