Dual redundant active/active brake-by-wire architecture

• US 6,820,946 B2
• Filed: 01/21/2003
• Issued: 11/23/2004
• Est. Priority Date: 07/22/1999
• Status: Expired due to Fees

• Current Assignee: Hydro-Aire, Inc. (Crane Company)
• Original Assignee: Hydro-Aire, Inc. (Crane Company)
• Inventors: Salamat, Bijan, Mackness, Robert F.
• Primary Examiner(s): Schwartz, Christopher P.
• Application Number:
  US10/348,469
• Publication Number:
  US 20030111895A1
• Time in Patent Office: 672 Days
• Field of Search: 303/DIG.9, 303/122.03, 303/122.04, 303/122.05, 303/122.08, 303/122.09, 303/122.1, 303/122.13, 303/122.14, 303/155, 303/158, 303/178, 303/3, 303/7, 303/9.61, 303/9.63, 303/15, 303/122, 244/111, 244/110.R, 244/110.A, 701/69, 701/70
• US Class Current: 303/122.09
• CPC Class Codes: B60T 2210/13 Aquaplaning, hydroplaning
• CPC Class Codes: B60T 2270/82 Brake-by-Wire, EHB
• CPC Class Codes: B60T 8/1703 for aircrafts
• CPC Class Codes: B60T 8/325 Systems specially adapted for aircraft
• CPC Class Codes: B60T 8/363 in hydraulic systems B60T8/3655, B60T8/3675 and B60T8/369 take precedence
• CPC Class Codes: Y10S 303/09 Plural processors

Abstract

The braking control system provides dual redundant control of hydraulically operated wheel braking for an aircraft. A primary hydraulic system provides hydraulic power for normal operation of the plurality of wheel brakes, and a secondary hydraulic system provides hydraulic power for alternate operation of the plurality of wheel brakes. The primary hydraulic system comprises at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel, the primary and secondary fluid channels being redundant and partitioned among the plurality of wheel brakes so that even if one of the primary hydraulic fluid control channels and one of the secondary channels fail to apply pressure, braking will be lost to only a portion of the wheel brakes and the loss will be in a symmetrical pattern.

Claims

1. In combination with an aircraft, an apparatus for dual redundant control of hydraulically operated wheel braking for the aircraft, the aircraft having right and left main landing gear and center landing gear that can move between a retracted position and an actuated position, the right, left and center landing gears having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system comprising a plurality of primary hydraulic fluid control channels and a plurality of secondary hydraulic fluid control channels, the primary and secondary hydraulic fluid control channels operating so that even if one of the primary hydraulic fluid control channels and one of the secondary hydraulic fluid control channels fail to apply pressure, braking will be lost to only a portion of the wheel brakes and the loss will be in a symmetrical pattern;

a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode, said secondary hydraulic system providing dual redundant analog brake-by-wire control in the alternate braking mode for the right and left main and center landing gears of the aircraft, and said secondary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel;

a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems; and

a monitor channel operatively connected to said primary and secondary hydraulic systems for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure.

2. The apparatus of claim 1, further comprising first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time.

3. The apparatus of claim 2, wherein said control unit comprises thrust lever switches, and said solenoid operated shut-off valves are implemented through said thrust lever switches to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the primary or secondary hydraulic systems during take off.

4. The apparatus of claim 3, further comprising a landing gear lever controlling retraction of the landing gears, and dual redundant switches on the landing gear lever to bypass the thrust lever switches to stop the wheels during climb when the thrust lever switches are advanced to enable wheel braking upon retraction of the right, left and center landing gears.

5. The apparatus of claim 4, wherein an anti-skid function of the normal braking mode is inhibited during retraction braking.

6. The apparatus of claim 3, wherein said control unit comprises a plurality of servo control valves controlled by corresponding dual solenoid coils for controlling the operation of said wheel brakes, respectively, and wherein said thrust levers comprise dual thrust lever switches that break both power and ground to said first and second solenoid operated shut-off valves for the primary hydraulic system and secondary hydraulic systems when one of said thrust levers is advanced.

7. The apparatus of claim 1, wherein said secondary hydraulic system comprises a plurality of accumulators for providing an alternate supply of hydraulic power.

8. The apparatus of claim 7, wherein said alternate supply of hydraulic power is provided for an emergency braking mode in the event that both the primary hydraulic system and the secondary hydraulic system are depressurized.

9. The apparatus of claim 7, wherein said alternate supply of hydraulic power is provided for an ultimate braking mode providing braking pressure to said plurality of wheel brakes.

10. The apparatus of claim 7, wherein said alternate supply of hydraulic power is provided for a parking brake mode providing braking pressure to said plurality of wheel brakes.

11. The apparatus of claim 1, wherein said plurality of brake pedals comprises a plurality of left brake pedals and a plurality of right brake pedals for controlling braking, and wherein said plurality of wheel brakes comprises a front pair of wheel brakes and an aft pair of wheel brakes, and wherein said primary hydraulic system primary and secondary hydraulic fluid control channels and said secondary hydraulic system primary and secondary hydraulic fluid control channels control all four wheels of the center landing gear.

12. The apparatus of claim 11, wherein wheel braking power is provided by center landing gear common fluid channels to the wheel brakes of the center landing gear on an axle pair basis.

13. The apparatus of claim 1, wherein said plurality of wheel brakes comprises a front pair of wheel brakes and an aft pair of wheel brakes for each of said right and left main landing gears, said front pair of wheel brakes and said aft pair of wheel brakes being arranged in adjacent pairs of said front and aft wheel brakes for each of said right and left main landing gears, and wherein wheel braking power is provided by main landing gear common fluid channels to said adjacent pairs of said front and aft wheel brakes to provide protection against asymmetrical wheel braking.

14. The apparatus of claim 1, wherein said secondary hydraulic system provides pressure for alternate braking using dual, independent, closed loop analog control circuits.

15. The apparatus of claim 1, wherein said monitor channel detects occurrence of loss of pressure in the primary hydraulic system, if any of the brakes has unwanted pressure applied, and if a fault is detected on the primary or secondary hydraulic systems that affects more than one wheel brake on each of the right, left and center landing gears.

16. The apparatus of claim 1, wherein said control unit further comprises a plurality of sensors for sensing the position of each said brake pedal.