Rotor Speed Setpoint Control for Quiet and Stable Rotorcraft Flight
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Solution Overview
Problem
Existing rotorcraft systems lack a solution for automatically regulating the main rotor's speed setpoint based on the absolute value of the vertical component of travel speed relative to a reference level, particularly during level flight above 500 feet, which limits performance and sound management.
Innovation Solution
A regulator device that measures current vertical elevation and travel speed components, using distinct control relationships to adjust the rotor speed setpoint automatically, with threshold values adapting to vertical speed, ensuring optimal performance and sound management across varying elevations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the main rotor speed is reduced to optimize power supply and reduce sound nuisance, then sound footprint is reduced, but flying performance deteriorates
Solution Approach 1:
The patent implements dynamic adaptation of the first threshold value S1 based on the vertical component Vz of travel speed. When Vz exceeds a threshold Vzc, the system switches to a first control relationship (acoustic optimization); when Vz is below Vzc, it switches to a second control relationship (performance optimization). This dynamic switching resolves the contradiction by adapting the control strategy to current flight conditions, allowing the system to optimize sound footprint during level flight while maintaining performance during vertical maneuvers.
Solution Approach 2:
The system changes the parameter S1 (first threshold value for vertical elevation) based on the vertical speed component Vz. This parameter adaptation allows the transition between two distinct control relationships NR1 and NR2, enabling the system to balance between sound reduction and performance maintenance by adjusting the threshold that triggers speed reduction based on current vertical motion state.
2Ease of operation
If a fixed threshold value for vertical elevation is used to control rotor speed, then control simplicity is maintained, but adaptability to different flight conditions deteriorates
Solution Approach 1:
The patent transforms the fixed threshold approach into a dynamic threshold system where S1 varies according to Vz (vertical speed component). The system automatically selects between two control relationships based on whether Vz exceeds Vzc, providing adaptability to different flight conditions while maintaining automated control simplicity through rule-based switching logic.
Solution Approach 2:
The threshold parameter S1 is changed based on the vertical speed component Vz. When Vz > Vzc, S1 equals Sc1 (first constant); when Vz ≤ Vzc, S1 equals Sc2 (second constant, greater than Sc1). This parameter adaptation enables the system to adapt to different flight phases (level flight vs. vertical maneuvers) while keeping the control logic automated and relatively simple.
3Object-generated harmful factors
If rotor speed is reduced during descent to manage sound, then sound footprint is reduced, but reliability of performance control deteriorates
Solution Approach 1:
The system dynamically adjusts control strategy based on vertical speed Vz. During descent phases where Vz indicates downward motion, the system can switch to the second control relationship NR2 that prioritizes performance reliability over sound reduction. This dynamic adaptation ensures reliable performance control during critical phases like descent while still enabling sound optimization during stable level flight conditions.
Solution Approach 2:
The threshold parameter S1 changes based on Vz to reflect different flight phases. During descent (negative Vz or Vz ≤ Vzc), the system uses Sc2 as the threshold, which triggers performance-oriented control. This parameter adaptation ensures that sound management does not compromise performance reliability during phases where performance control is critical.
Data Source
AI summary
A regulator device for regulating a control setpoint for a speed of rotation, written NR, for at least one main rotor of a rotorcraft, the rotorcraft including at least one measurement member for taking measurements representative of a current vertical elevation of the rotorcraft relative to a reference level Ref; and measurement means serving to measure at least one vertical component of a travel speed of the rotorcraft relative to the air surrounding the rotorcraft, the regulator device for regulating the control setpoint of the speed including management means for automatically controlling the control setpoint for the speed in accordance with at least two predetermined control relationships that are distinct from each other.