Fluid-pressure and analogous brake systems – Electric control
Reexamination Certificate
1999-07-15
2001-10-02
Oberleitner, Robert J. (Department: 3613)
Fluid-pressure and analogous brake systems
Electric control
C303S122040, C303SDIG009, C318S362000, C244S11000H, C244S11000H
Reexamination Certificate
active
06296325
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to braking systems for vehicles, and more particularly to a method for connecting and distributing power to an electromechanical braking system in an aircraft.
BACKGROUND OF THE INVENTION
Various types of braking systems are known. For example, hydraulic, pneumatic and electromechanical braking systems have been developed for different applications. The aerospace industry presents unique operational and safety issues with regard to many braking systems. For example, the need for system redundancy in case of a system or component failure is particularly germane to braking operations of an aircraft.
Brake system architectures for aircraft have been developed previously which meet different redundancy, performance and safety requirements. Such architectures include, for example, redundant digital brake control units (BSCUs) which carry out the brake control and antiskid processing functions. In addition, such architectures include, for example, redundant electromechanical actuator controllers (EMACs) which convert commands from the BSCUs to brake actuator forces. Each EMAC provides electrical power to electromechanical brake actuators included within the brakes for the wheels of the aircraft.
FIG. 1
represents such a brake system architecture which has been developed in the past. The architecture, generally designated in
FIG. 1
as braking system
30
, includes the aforementioned BSCUs and EMACs which are represented collectively as an electromechanical braking controller
60
. The controller
60
receives as its primary inputs i) the brake command signals from pilot brake pedal transducers
46
located in the cockpit of the aircraft, and ii) the outputs of torque and wheel speed sensors
62
included as part of a brake
34
on each wheel
36
of the aircraft.
The braking system
30
receives power from three primary power busses and a secondary power buss included within the aircraft. As is known, an aircraft oftentimes will include multiple power busses. In the exemplary embodiment, the aircraft includes primary power busses PWR
1
, PWR
2
and PWRess. Each power buss preferably is independent of one or more of the other power busses to provide a level of redundancy. For example, the power buss PWR
1
consists of an alternating-current (AC) power source AC
1
and a commonly generated direct-current (DC) power source DC
1
. Similarly, the power buss PWR
2
consists of an AC power source AC
2
and a commonly generated DC power source DC
2
; and the power buss PWRess consists of an AC power source ACess and commonly generated DC power source DCess.
The power buss PWR
1
(i.e., AC
1
and DC
1
) may be derived from power generated by the left wing engine in the aircraft, for example. Similarly, the power buss PWR
2
(i.e., AC
2
and DC
2
) may be derived from power generated by the right wing engine. In this manner, if the left wing engine or the right wing engine fails, power is still available to the system
30
via the power buss corresponding to the other engine.
The power buss PWRess (i.e., ACess and DCess) may be derived from power generated by the parallel combination of the left wing engine and the right wing engine. In such manner, power from the power buss PWRess will still be available even if one of the engines fail. In addition, DCess can be powered by a battery in case of total loss of the aircraft engines.
More particularly, the aircraft further includes a DC power buss supplied by a battery on board the aircraft. This power is represented by a DChot power source. The battery may be charged via power from one of the other power sources, or may be charged separately on the ground. The DChot power source is configured to provide battery power to the DCess power buss in the event of loss of AC power.
Various circumstances can arise where power from one or more of the power busses may become unavailable. For example, the left wing engine or the right wing engine could fail causing the PWR
1
(AC
1
/DC
1
) and PWR
2
(AC
2
/DC
2
) power sources to go down, respectively. Alternatively, power generating equipment such as a generator, inverter, or other form of power converter could fail on one of the respective power busses resulting in the AC
1
/DC
1
, AC
2
/DC
2
and/or ACess/DCess power sources becoming unavailable. In addition, a failure can occur in the cabling providing the power from the respective power sources to the system
30
, thus effectively causing the respective power source to no longer be available. For this reason, the routing of the power cables for the different busses preferably occurs along different routes throughout the plane to avoid catastrophic failure on all the power buss cables at the same time.
As mentioned above, such previously developed systems have been shown to satisfy system redundancy, performance and safety requirements associated within an aircraft braking system. Nevertheless, there is a desire to improve the capabilities of such braking systems with respect to other possible failures within an aircraft or other vehicle. For example, there is a strong need in the art for a method for partitioning the power buss(es) within the braking system to reduce the risk of impairing or failing a power buss or supply as a consequence of a system or component failure. Moreover, there is a strong need in the art for a method for further maintaining brake control in an emergency or parking mode despite loss of a power buss and or BSCU, for example.
SUMMARY OF THE INVENTION
The present invention provides a manner for arranging the components and power connection points within a braking system architecture in order to better maintain isolation of the power busses, and thereby improve overall integrity of the system, while still meeting system redundancy, performance and safety requirements as in the past. In addition, the invention provides a manner for connecting and efficiently using available power in emergency braking and parking modes.
In accordance with one particular aspect of the invention, a method is provided for distributing power to an electromechanical braking system. The braking system includes a plurality of brake actuators for effecting a braking torque on wheels of a vehicle, a plurality of electromechanical actuator controllers (EMACs) for providing drive control of the brake actuators in response to brake command signals, and at least one brake control unit (BSCU) for converting an input brake command signal into the brake command signals which are provided to the EMACs. The method includes the steps of configuring at least two of the plurality of EMACs to function redundantly in providing drive control to the brake actuators in response to the brake command signals; and providing power to the at least two EMACs via respective power busses having different power sources.
According to another aspect of the invention, a method for distributing power to an electromechanical braking system are provided in which the system includes a plurality of brake actuators for effecting a braking torque on wheels of a vehicle, at least one electromechanical actuator controller (EMAC) for providing drive control of the brake actuators in response to brake command signals, and a plurality of brake control units (BSCUs) for converting an input brake command signal into the brake command signals which are provided to the at least one EMAC. The method includes the steps of configuring at least two of the plurality of BSCUs to function redundantly in providing brake command signals to the at least one EMAC in response to the input brake command signal; and providing power to the at least two BSCUs via respective power busses having different power sources.
In accordance with yet another aspect of the invention, a method for controlling braking in an electromechanical braking system comprising at least one brake actuator for effecting a braking torque on a wheel of a vehicle, at least one electromechanical actuator controller (EMAC) for providing drive control of the brake actuator in response to
Brown Rollin W.
Brundrett Robert L.
Corio Lawrence F.
Garcia Jean Pierre
Lauzier Cedrick
Oberleitner Robert J.
Renner , Otto, Boisselle & Sklar, LLP
Siconolfi Robert A.
The B. F. Goodrich Company
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