Aircraft Alternate Braking Pressure Control for Fast Failure Switchover
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Solution Overview
Problem
In aircraft brake control systems with a primary/alternate architecture, there is a significant delay in transitioning from the primary system to the alternate system during failures, which can be critical during events like RTO or landing.
Innovation Solution
The method involves initiating the aircraft braking system by receiving a first brake command at both the primary and alternate systems. When the primary system loses control of the brakes, the method seamlessly transitions to the alternate system by adjusting brake pressures, ensuring minimal disruption through the use of shuttle valves and predetermined pressure differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the alternate system is kept in stand-by mode with minimal activation, then system reliability is improved by reducing wear and power consumption, but switching time increases significantly when primary system fails
Solution Approach 1:
The patent applies preliminary action by pre-charging the alternate system's accumulator to a predetermined pressure level before failure occurs. This allows the alternate system to be ready for immediate operation upon primary system failure, reducing switching time while avoiding continuous operation that would increase wear and power consumption.
Solution Approach 2:
The patent implements dynamics by transitioning the alternate system from a static stand-by state to an dynamically activated state with pre-charged accumulators. The system adapts its readiness level based on operational requirements, allowing rapid switching when needed while maintaining energy efficiency during normal operation.
2Loss of time
If the alternate system is pre-charged to full operating pressure, then switching time is reduced, but power consumption and system complexity increase
Solution Approach 1:
The patent applies parameter changes by setting the alternate system accumulator pressure to a predetermined level that is sufficient for rapid switching but less than full operating pressure. This optimized pressure level reduces the energy required to maintain stand-by readiness while ensuring adequate braking capability during transition.
Solution Approach 2:
The patent uses partial action by charging the alternate system accumulator to only the necessary predetermined pressure level required for safe switching, rather than charging it to full operating pressure. This provides sufficient braking capability for the transition period without the excessive energy consumption of full charging.
3Loss of time
If the shuttle valve switches quickly to the alternate system, then braking disruption is minimized, but pressure instability occurs during transition
Solution Approach 1:
The patent applies beforehand cushioning by pre-charging the alternate system accumulator to a predetermined pressure level before switching occurs. This pre-prepared pressure buffer cushions the transition, allowing rapid shuttle valve switching while maintaining pressure stability and avoiding braking disruption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables rapid and efficient transition from the primary to the alternate braking system, minimizing braking disruption and ensuring safe operation during critical events by maintaining continuous braking capability.
Implementation Method 1
switching to the alternate system includes toggling a shuttle valve in response to a pressure change such that the shuttle valve switches operation from the primary system to the alternate system
Data Source
AI summary
A method of controlling an aircraft braking system includes initiating the aircraft braking system by receiving a first brake command at a primary system to actuate braking via the primary system, receiving the first brake command at an alternate system, and in response to the primary system losing an ability to control a brake, controlling the braking of the brake via the alternate system.