Rotorcraft Longitudinal Airspeed Control via Acceleration Integration
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Solution Overview
Problem
As rotorcraft become larger and more complex, the differences between flying rotorcraft and fixed-wing aircraft become more pronounced, with tightly coupled flight parameters and controls, leading to instability and increased pilot workload, especially in varying speed regimes.
Innovation Solution
A system and method utilizing multiple airspeed sensors and inertial sensors, combined with a flight control computer that filters and scales data to generate a determined longitudinal airspeed, reducing phase lag and improving flight control signals for smoother operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If airspeed data is filtered to reduce noise, then measurement precision is improved, but phase lag increases causing control delays
Solution Approach 1:
The patent introduces acceleration data from inertial sensors as an intermediary element to compensate for the phase lag caused by filtering airspeed data. The filtered airspeed data and filtered acceleration data are combined through integration and scaling operations, where the acceleration data acts as a leading indicator that predicts future airspeed changes, thereby reducing the effective phase lag without compromising the noise reduction benefits of filtering.
2Power
If rotorcraft size and complexity increase, then power and capacity are improved, but flight stability deteriorates due to tightly coupled parameters
Solution Approach 1:
The patent segments the tightly coupled flight parameters into separate controllable components by using individual sensors for airspeed and acceleration, processing them through separate filtering channels, and then combining them in a controlled manner. This segmentation allows independent optimization of each parameter's processing while maintaining overall system stability, preventing the coupling effects that cause instability in larger rotorcraft.
3Measurement precision
If multiple sensors are used to improve measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a multi-functional processing system where the same filtering and integration architecture processes both airspeed data and acceleration data. The flight control computer performs multiple functions: filtering airspeed data, filtering acceleration data, integrating acceleration data, scaling the integrated data, and combining it with airspeed data. This universal processing approach reduces overall system complexity compared to having separate dedicated systems for each function.
Data Source
AI summary
A rotorcraft includes airspeed sensors, inertial sensors, and a flight control computer (FCC) operable to provide a longitudinal control for the rotorcraft. The FCC receives a first indication of longitudinal airspeed from the airspeed sensors and receives a first indication of longitudinal acceleration from the inertial sensors. The FCC generates a filtered indication of longitudinal airspeed from the first indication of longitudinal airspeed and generates a scaled and filtered indication of longitudinal acceleration from the first indication of longitudinal acceleration. The FCC combines the filtered indication of longitudinal airspeed with the scaled and filtered indication of longitudinal acceleration to generate a determined longitudinal airspeed. The FCC generates a flight control signal to control operation of the rotorcraft, the flight control signal based on the determined longitudinal airspeed.