Aircraft Brake Controller Diagnostic Testing During Gear Retraction
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Solution Overview
Problem
Aircraft braking systems often fail to detect malfunctions before, during, or after landing gear retraction, posing a risk as existing methods are inadequate for identifying issues in real-time.
Innovation Solution
A method and system that involve sending a test command set to an electromechanical actuator and brake servo valve during landing gear retraction, receiving feedback, comparing it with a predetermined signature and historical data to determine if a malfunction is present, and estimating the end point of a maintenance interval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If braking pressure is applied to keep the wheel stationary during landing gear retraction, then the wheel position is controlled, but the ability to detect brake system malfunctions is lost
Solution Approach 1:
The system performs a brake system diagnostic test before landing gear retraction by sending a test command set to the brake components and comparing the response to a predetermined signature. This preliminary detection occurs when the wheel is rotating, allowing malfunction identification before the braking function is critically needed during retraction.
Solution Approach 2:
The system receives feedback from brake components (electromechanical actuator, brake servo valve, wheel sensor) during the diagnostic test and compares it with expected feedback patterns. This feedback mechanism enables real-time detection of deviations from normal operation, allowing malfunction detection without compromising wheel position control during actual braking operations.
2Reliability
If the brake system is tested during landing gear retraction, then malfunction detection capability is improved, but the complexity of the testing system increases
Solution Approach 1:
The brake controller performs multiple functions: it controls braking operations during landing gear retraction and simultaneously conducts diagnostic tests by sending test command sets and analyzing feedback. This multi-functionality allows malfunction detection without requiring a separate dedicated testing system, thereby limiting the increase in system complexity.
Solution Approach 2:
The brake system performs self-diagnosis by having the brake controller send test commands to its own components (electromechanical actuator, brake servo valve) and evaluate the responses. This self-service capability enables autonomous malfunction detection without external testing equipment, reducing overall system complexity.
3Loss of time
If the diagnostic test is performed when the wheel is rotating, then the test can be conducted before retraction, but the wheel must be decelerated to test braking effectiveness
Solution Approach 1:
The system dynamically adjusts the testing approach based on wheel rotational velocity. The brake controller can send test command sets at different wheel speeds and interpret feedback accordingly, allowing the diagnostic to be performed during the natural deceleration process without requiring a separate stationary test phase.
Solution Approach 2:
The diagnostic testing is performed periodically during the landing gear retraction sequence at predetermined intervals or trigger points. This periodic action allows malfunction detection to be integrated into the existing operational cycle, minimizing additional time requirements and accommodating wheel speed variations.
Data Source
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AI summary
Systems and methods disclosed herein may be useful for testing braking systems for use in, for example, an aircraft. A system is disclosed that allows for built in testing. For example, a method if provided comprising sending, from a brake controller, a test command set to at least one of an electromechanical actuator (EMAC) and a brake servo valve (BSV) in response to a landing gear retraction, receiving, at the brake controller, feedback from the at least one of the EMAC and the BSV in response to the test command set, and comparing, at the brake controller, the feedback with a predetermined signature.