Antiskid Wheel Reference Speed Estimation for Braking Control
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Solution Overview
Problem
Aircraft brake control systems face issues with incorrect calculation of wheel reference speed, leading to erroneous antiskid desired pressure and inadequate braking pressure due to parameters like tuning of the brake control algorithm, resulting in 'pressure droop' and suboptimal braking performance.
Innovation Solution
The system calculates wheel reference speeds for multiple wheels and determines a wheel reference estimate as the arithmetic mean, using this to decide whether to use individual wheel speeds or the mean speed for antiskid pressure calculation, ensuring accurate pressure application by determining if each wheel speed is within a threshold of the estimated speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If wheel reference speed is calculated using individual wheel speeds, then braking response is fast, but calculation accuracy deteriorates leading to pressure droop
Solution Approach 1:
The patent combines multiple wheel reference speed calculations from different landing gears and merges them into a single averaged wheel reference speed. This merging approach resolves the contradiction by utilizing data from multiple wheels to improve accuracy while maintaining the responsive nature of individual wheel speed measurements.
Solution Approach 2:
The patent creates a universal wheel reference speed that serves as a common reference for antiskid control across multiple landing gears. This multi-functional reference speed improves calculation accuracy by being applicable system-wide while still allowing individual wheel braking responses.
2Productivity
If antiskid desired pressure is calculated using individual wheel reference speed, then pressure application is responsive, but braking performance deteriorates due to pressure droop
Solution Approach 1:
The patent implements a feedback mechanism where the calculated wheel reference estimate is continuously compared against individual wheel reference speeds. This feedback loop ensures that pressure application remains responsive while correcting for accuracy errors that would otherwise cause pressure droop and performance degradation.
Solution Approach 2:
The patent changes the parameter used for pressure calculation from individual wheel reference speed to an averaged wheel reference estimate. This parameter change improves reliability by using a more accurate reference while maintaining responsiveness through the threshold comparison mechanism.
3Measurement precision
If wheel reference estimate is calculated as arithmetic mean of multiple wheel speeds, then speed measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies a simple arithmetic mean calculation to average multiple wheel speeds, creating an improved wheel reference estimate. This parameter transformation approach improves measurement precision while avoiding complex algorithms, thereby limiting the increase in device complexity to minimal computational overhead.
4Ease of operation
If individual wheel speeds are used for antiskid control, then control responsiveness is high, but braking consistency across landing gears deteriorates
Solution Approach 1:
The patent merges wheel speed data from multiple landing gears into a unified wheel reference estimate. This merging maintains control responsiveness by still using individual wheel speeds for comparison while improving braking consistency across all landing gears through the averaged reference.
Solution Approach 2:
The patent creates an equipotential reference by averaging wheel speeds across different landing gears, ensuring that all wheels operate from the same reference potential. This approach maintains individual wheel control responsiveness while ensuring consistent braking pressure across the entire aircraft landing gear system.
Data Source
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AI summary
Systems and methods (300, 500) are disclosed herein for controlling braking systems. In this regard, a method for controlling brakes may comprise receiving (302, 302a), by an antiskid control (ASK), a first wheel speed, calculating (304, 304a), by the ASK, a first wheel reference speed (WRS), and calculating (306, 306a), by the ASK, a first wheel reference estimate (WRE). In various embodiments, the method may further comprise determining (308, 308a) if the first WRS is within a threshold value of the first WRE. In various embodiments, the method may further comprise calculating an ASK desired pressure. The ASK desired pressure may be calculated using the first WRS in response to the first WRS being within the threshold value of the first WRE. The ASK desired pressure may be calculated using the first WRE in response to the first WRS being outside the threshold value of the first WRE.