Rotor Phase Control for Rotorcraft
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Solution Overview
Problem
Rigid rotor systems in aircraft face challenges in ensuring correct on-axis commands for pitching and rolling maneuvers due to varying rotor phase lag with speed and differential cyclic commands, leading to off-axis moments and undesirable inter-hub moments.
Innovation Solution
A method and apparatus that utilize sensors and processors to determine independent rotor phase lag for each axis, issuing commands to provide on-axis moments by adjusting the phasing kinematics separately for each axis, using tables or maps to correct for phase lag variations and prevent off-axis moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional rotor phase lag control is used, then the rotor system maintains simple control structure, but the control accuracy deteriorates due to varying phase lag with speed and position
Solution Approach 1:
The patent implements dynamic phase lag adjustment by continuously varying the phase lag compensation values based on real-time rotor speed and blade position feedback. The control system dynamically updates the phase lag parameters during flight operations, allowing the rotor control to adapt to changing flight conditions and maintain accurate on-axis moment generation across the entire operating envelope.
Solution Approach 2:
The patent changes the control parameters by introducing independent phase lag values for different rotor positions and speeds. Instead of using a fixed phase lag value, the system modifies the phase lag parameter as a function of rotor speed and blade azimuth position, enabling precise compensation for the varying phase lag characteristics throughout the rotor's operational range.
2Manufacturing precision
If independent phase lag adjustment for each axis is implemented, then on-axis moment accuracy is improved, but the control system complexity increases
Solution Approach 1:
The patent segments the rotor control into independent phase lag adjustments for each axis (pitch and roll). By treating the phase lag compensation as separate controllable parameters for each rotational axis, the system can independently optimize on-axis moment generation for pitching and rolling maneuvers without interference between axes, thereby improving overall control precision.
Solution Approach 2:
The control system incorporates feedback mechanisms that monitor the actual rotor response and compare it with the desired on-axis moments. Based on this feedback, the system continuously adjusts the independent phase lag parameters for each axis to minimize deviations and maintain accurate control, enabling the complex multi-parameter control to self-optimize during operation.
3Object-generated harmful factors
If fixed phase lag control is used, then the control system remains simple, but off-axis moments and inter-hub moments occur during maneuvers
Solution Approach 1:
The patent applies preliminary anti-action by pre-calculating and compensating for the expected phase lag variations at different rotor positions and speeds before the actual maneuvers occur. The control system incorporates lookup tables or mathematical models that predict the phase lag behavior, allowing the control inputs to be pre-adjusted to counteract the anticipated off-axis and inter-hub moments, thereby preventing these harmful effects before they manifest.
Data Source
AI summary
Embodiments are directed to obtaining data from at least one sensor, processing, by a processor, the data to determine an independent rotor phase lag for each of a plurality of axes associated with a rotorcraft, and issuing, by the processor, at least one command to provide for on-axis moments in accordance with the independent rotor phase lag for each of the axes.