Blade Flap Measurement Correction for Rotorcraft
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Solution Overview
Problem
Existing sensor systems for measuring blade flapping in rotorcraft are prone to inaccuracies, which affect the precision of directional control and flight operations.
Innovation Solution
A measurement system incorporating a rotary variable differential transformer (RVDT) and a processing system with correction processes, including filter gain and phase compensators, to accurately measure and correct blade flapping angles, accounting for rotor RPM and torque variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor system is placed proximate to the rotor blades to measure flapping angle, then flapping angle measurement is obtained, but measurement accuracy deteriorates due to susceptibility to inaccuracies
Solution Approach 1:
The patent introduces an intermediary processing system that receives raw flapping angle measurements from proximate sensors and corrects them using reference measurements from remote sensors. This intermediary correction process eliminates the need to place highly accurate sensors directly near the rotating blades while still achieving high measurement accuracy through the combination of proximate and remote sensor data.
Solution Approach 2:
The system uses feedback by continuously comparing proximate sensor measurements with remote reference measurements and applying real-time corrections. The correction process feeds back adjusted flapping angle values that compensate for inaccuracies in the proximate sensors, maintaining reliable measurements despite the challenging environment near rotating blades.
2Speed
If proximate sensor systems are used for flapping measurement, then real-time measurement capability is achieved, but measurement reliability deteriorates due to environmental inaccuracies
Solution Approach 1:
The processing system acts as an intermediary that combines real-time proximate measurements with corrected reference data, maintaining the speed advantage of proximate sensors while eliminating their reliability disadvantages through mathematical correction based on remote reference measurements.
Solution Approach 2:
The patent replaces the need for mechanically robust high-accuracy sensors near rotating blades with a computational correction system. Instead of relying on physically resilient sensors, the system uses software-based correction algorithms to achieve accuracy, substituting mechanical sensor resilience with computational reliability.
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
The system provides improved accuracy in blade flapping measurements, enhancing directional control and flight stability by compensating for errors and noise, thereby improving the overall performance of rotorcraft.
Implementation Method 1
A rotary variable differential transformer (RVDT) can be used to convert the displacement into an electrical signal
Data Source
AI summary
A rotorcraft comprising a rotor blade designed to flap about a hinge point, a measurement system designed to measure blade flapping, and a processing system designed to alter blade flapping measurements. The processing system further comprises a correction process to alter a blade flapping measurement dependent on rotor RPM or rotor torque.