Aircraft Electric Braking System Redundancy
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Solution Overview
Problem
Current electrically actuated aircraft braking systems face potential simultaneous failure of electro-mechanical actuator controllers (EMACs) due to their complex nature, leading to partial or full loss of braking control, which is undesirable for safety and reliability.
Innovation Solution
The system incorporates a dual redundant braking control unit (BCU) configuration with an emergency braking control unit (eBCU) and 'smart' EMACs that include dissimilar motor controllers for normal and emergency modes, packaged within a common line replaceable unit (LRU), allowing for switching between normal and emergency channels to prevent common mode failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If identical EMACs are used to maximize commonality of parts, then manufacturing cost and design complexity are reduced, but the risk of simultaneous failure of multiple EMACs increases
Solution Approach 1:
The patent applies asymmetry by using dissimilar EMAC designs in different landing gear bays. Specifically, first EMACs associated with first wheel and brake groups have a different design from second EMACs associated with second wheel and brake groups. This asymmetric configuration ensures that a common-mode failure affecting one EMAC design will not affect the other, thereby preventing simultaneous failure while still maintaining manageable manufacturing complexity through standardized dissimilar components.
2Reliability
If multiple BCUs are provided for redundancy, then fault tolerance is improved, but system complexity and the potential for simultaneous EMAC failure increase
Solution Approach 1:
The patent applies segmentation by dividing the braking control system into separate, independent segments. Each landing gear bay has its own dedicated BCU and EMACs that are electrically isolated from other bays. This segmentation ensures that a failure in one BCU or EMAC does not propagate to other parts of the system, providing fault tolerance while actually reducing overall system complexity through modular, independent units.
3Speed
If EMACs are disposed within the landing gear bay electrically connected to brake EMAs, then response time is reduced, but the complexity of electrical connections and potential failure points increase
Solution Approach 1:
The patent applies merging by integrating the EMAC and its associated brake EMAs into a single self-contained landing gear bay assembly. Each EMAC is disposed within its respective landing gear bay and electrically connected only to the brake EMAs in that same bay, creating localized functional units. This merging reduces response time by minimizing electrical signal paths while managing connection complexity through clear, localized associations between control and actuation components.
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 configuration enhances the reliability and safety of the braking system by providing redundant control pathways, reducing the risk of simultaneous failure and ensuring continued braking functionality even in case of BCU or EMAC failures, thereby maintaining aircraft control during normal and emergency operations.
Implementation Method 1
an electro-mechanical brake actuator (EMAbrake) proximate a wheel of the aircraft, the EMAbrake including a motor
Implementation Method 2
hardware for generating a pulse-width modulation signal
Data Source
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AI summary
An electrically actuated braking system for an aircraft. The system includes: an electro-mechanical brake actuator (EMAbrake) proximate a wheel of the aircraft, the EMAbrake including a motor; an electro-mechanical actuator controller (EMAC) including a motor controller for generating a drive signal for the EMAbrake; a braking control unit (BCU) for generating a braking force command signal for the EMAC during a normal mode of operation; and an emergency braking control unit (eBCU) for generating a braking force command signal for the EMAC during an emergency operating mode. The eBCU is disposed together with the EMAC in a common line replaceable unit (LRU).