Servo Valve Health Monitoring via Cross-System Pressure Validation
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Solution Overview
Problem
In aircraft braking systems, it is challenging to detect deteriorating conditions or faults in servo valves when the hydraulic pressure output remains constant, making it difficult to maintain proper braking forces, as existing monitoring systems struggle to differentiate between normal and faulty operations.
Innovation Solution
A system that includes a controller communicating with non-transitory memory to receive and compare hydraulic pressure signals from primary and non-primary braking systems, validating pressure sensors and monitoring the health status of servo valves by comparing these signals over time, and alerting on discrepancies, thereby ensuring accurate health status assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic pressure output is maintained at a constant level by compensating electrical signal, then proper braking forces are maintained, but deteriorating conditions or faults in servo valve cannot be detected
Solution Approach 1:
The system performs preliminary validation of the pressure sensor by comparing readings from primary and non-primary braking systems before actual monitoring begins. This preliminary action ensures the sensor is functioning correctly, establishing a baseline for future fault detection while maintaining reliable braking forces through compensating electrical signals.
Solution Approach 2:
The system continuously monitors the relationship between electrical current input and hydraulic pressure output, using feedback loops to detect deviations from expected performance. This feedback mechanism allows the system to identify deteriorating servo valve conditions while maintaining proper braking forces through real-time signal compensation.
2Productivity
If pressure sensor is used to monitor servo valve health, then health status can be monitored, but sensor failures or inaccuracies can lead to false monitoring results
Solution Approach 1:
The system creates a redundant copy of the pressure measurement capability by utilizing pressure sensors in both primary and non-primary braking systems. By comparing these duplicate measurements, the system can validate sensor accuracy and detect faults, ensuring reliable health monitoring without sacrificing monitoring capability.
Solution Approach 2:
The pressure sensor validates itself through comparison with readings from the non-primary braking system. This self-service mechanism allows the sensor to detect its own failures or inaccuracies, maintaining monitoring accuracy while preserving continuous health monitoring capability.
3Reliability
If closed loop control is used to maintain hydraulic pressure, then proper braking forces are maintained, but it becomes difficult to distinguish between normal operation and faulty conditions
Solution Approach 1:
The system establishes a preliminary validation phase where pressure sensor readings are compared before normal monitoring begins. This preliminary action creates a reference state that preserves fault information, allowing the system to distinguish between normal closed-loop operation and actual faults even while maintaining constant hydraulic pressure.
Solution Approach 2:
The system adds another dimension to monitoring by comparing pressure readings across two independent braking systems (primary and non-primary). This dimensional expansion allows the system to maintain reliable braking control in each system while using the comparison to preserve fault condition information that would be lost in single-system monitoring.
Data Source
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Figure 1-B
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AI summary
Braking control systems and methods, such as for an aircraft, use a first pressure sensor (48) and a second pressure sensor (49) from a non-primary braking system to validate the first pressure sensor. In response to the first pressure sensor being validated, a health status of a servo valve is monitored based on predetermined characteristics about the servo valve, including electrical current input into the servo valve and hydraulic pressure output from the servo valve.