Redundant architecture for brake-by-wire system
A redundant architecture for a brake-by-wire system is provided. The system includes a pressure source; at least one brake actuator for exerting a braking force on a wheel as a result of pressure provided by the pressure source; at least one servo valve for controlling an amount of pressure provided from the pressure source to the at least one brake actuator in response to a servo valve command signal; a shutoff valve in line with the at least one servo valve for preventing pressure from the pressure source from being provided to the at least one brake actuator in response to a shutoff valve command signal; a processor which executes code in order to carry out brake control operations, the processor outputting the servo command signal and the shutoff valve command signal in response to system inputs provided to the processor; a shutoff valve enable device for performing brake control operations redundant at least in part with the processor and based on the system inputs, and selectively enabling shutoff valve command signals from the processor to be provided to the shutoff valve based on the redundant brake control operations.
1. A redundant architecture for a brake-by-wire system, comprising:
a pressure source;
at least one brake actuator for exerting a braking force on a wheel as a result of pressure provided by the pressure source;
at least one servo valve for controlling an amount of pressure provided from the pressure source to the at least one brake actuator In response to a servo valve command signal;
a shutoff valve in line with the at least one servo valve for preventing pressure from the pressure source from being provided to the at least one brake actuator in response to a shutoff valve command signal;
a processor which executes code in order to carry out brake control operations, the processor outputting the servo valve command signal and the shutoff valve command signal in response to system inputs provided to the processor;
a shutoff valve enable device for performing brake control operations redundant at least in part with the processor and based on the system inputs, and selectively enabling shutoff valve command signals from the processor to be provided to the shutoff valve based on the redundant brake control operations.
2. The system of claim 1 , wherein the processor provides a brake control loop which is primarily software based, and the shutoff valve enable device provides a redundant brake control loop which is primarily hardware based.
3. The system of claim 2 , wherein the shutoff valve enable device is configured primarily of digital logic.
4. The system of claim 1 , wherein the shutoff valve enable device is operative in response to system inputs representing brake pedal commands.
5. The system of claim 4 , wherein the brake pedal commands are represented by a plurality of channels of redundant brake pedal commands, and the shutoff valve enable device selects between channels.
6. The system of claim 5 , wherein the shutoff valve enable device selects between the channels based on system information indicating the health of a particular channel.
7. The system of claim 4 , wherein the brake pedal commands are analog signals and the shutoff valve enable device converts the analog signals to discrete signals.
8. The system of claim 7 , wherein the shutoff valve enable device is configured primarily within a digital logic array, and the discrete signals serve as inputs within the digital logic array.
9. The system of claim 1 , wherein the shutoff valve enable device is operative in response to system inputs representing autobrake commands on an aircraft.
10. The system of claim 1 , wherein the shutoff valve enable device is operative in response to system inputs representing gear retract braking commands on an aircraft.
11. The system of claim 1 , wherein the wheel is a wheel of an aircraft.
12. The system of claim 1 , wherein the pressure source is a hydraulic source.