Aircraft Brake Control System Wire Degradation Detection
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Solution Overview
Problem
Aircraft brake control systems face uncommanded brake overdrive conditions due to corrosion and degradation of wires between the electric brake actuation controller and load cells, leading to force errors and potentially dangerous situations.
Innovation Solution
The system monitors load cell currents and excitation voltage signals to detect resistance disturbances, comparing the sum of load cell output signals with the sum of excitation voltage signals to identify uncommanded brake overdrive conditions, thereby preventing excessive braking forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If connecting wires between the electric brake actuation controller and load cell are used to transmit signals, then the system can function, but the wires may corrode and degrade causing force errors and uncommanded brake overdrive conditions
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the actual current through the load cell and comparing it with the expected current based on the control signal. This feedback loop allows the system to detect wire degradation or corrosion by identifying discrepancies between commanded and actual load cell currents, enabling early warning before catastrophic failure occurs.
Solution Approach 2:
The patent introduces an intermediary monitoring function that acts as a mediator between the control signal and the actual brake force application. By inserting a current sensing and comparison mechanism in the signal path, the system can detect anomalies caused by wire degradation without directly interfering with the primary control function, thus preventing uncommanded brake overdrive conditions.
2Force
If the electric brake actuation controller provides high output signal to ensure sufficient braking force, then braking performance is improved, but wire degradation may cause excessive force application leading to uncommanded brake overdrive
Solution Approach 1:
The system uses feedback by continuously measuring the actual current through the load cell and comparing it with the expected current derived from the control signal. This closed-loop monitoring ensures that even high output signals are accurately controlled, as any deviation caused by wire degradation is detected and can trigger protective actions to prevent excessive brake force application.
Solution Approach 2:
The patent applies preliminary action by detecting wire degradation early through current monitoring before it leads to uncommanded brake overdrive. The system proactively identifies potential failures by comparing actual and expected currents, allowing preventive measures to be taken before the wire degradation causes dangerous excessive braking forces.
3Reliability
If monitoring and detection systems are added to detect wire degradation, then safety is improved, but device complexity increases
Solution Approach 1:
The monitoring system leverages existing system components (current sensing capabilities, microprocessor units already present in the brake control system) to perform wire degradation detection. By making the existing system serve dual purposes (both control and monitoring), the patent minimizes additional complexity while improving safety through intelligent use of available resources.
Solution Approach 2:
The patent implements multi-functionality by designing the monitoring system to use the same hardware resources (current sensors, microprocessors) for both primary brake control and wire degradation detection. This universal approach allows one set of components to perform multiple functions, reducing overall system complexity while enhancing safety through continuous monitoring.
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 method effectively detects and prevents uncommanded brake overdrive conditions, enhancing safety and reliability by accurately measuring and controlling braking forces.
Implementation Method 1
The EBAC is configured to receive a sensed voltage from each individual load cell of a plurality of individual load cells in parallel
Data Source
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AI summary
A method is provided for detecting an uncommanded brake overdrive condition in an aircraft brake control system. Method comprises monitoring, by an electric brake actuator controller (EBAC) (4) in the brake control system, at least one of the following: a load cell current for deviation from a nominal load cell current and a load cell output signal (LC Sig+) and (LC Sig-) of a plurality of individual load cells (6) and an excitation voltage signal comprising a (Vexc+) signal and a (Vexc-) signal. EBAC (4) detects at least one resistance disturbance indicating the uncommanded brake overdrive condition if load cell current is less than nominal load cell current, if an absolute value of the difference between a sum of LC Sig+ LC Sig- for at least one individual load cell and a sum of Vexc+ + Vexc- is greater than a predefined threshold, or both.