Rotor Clearance Control via Dynamic Allocation
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Solution Overview
Problem
Rotary wing aircraft with dual rotor main rotor assemblies face challenges in maintaining safe clearance between blade tips due to varying flight mechanics, requiring effective control methods that adapt to aircraft velocity and flight path.
Innovation Solution
A flight control system that measures the angle of deviation between rotor disks, determines the aircraft's flight state, and allocates control settings to axis-controlling devices to maintain a suitable pitch and clearance, using sensors and a control allocation module to generate commands for controlling the clearance between rotor disks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional clearance control methods are used, then the system is simple to operate, but the reliability of preventing blade tip contact is insufficient under varying flight conditions
Solution Approach 1:
The control system continuously measures the actual clearance between rotor disks using sensors and compares it with desired clearance values. Based on this feedback, the control allocation module dynamically adjusts control settings to maintain safe clearance, thereby improving reliability without requiring overly complex hardware architecture
Solution Approach 2:
The system dynamically adapts control allocations based on real-time flight conditions (velocity, flight path, rotor disk angles). By making the control system dynamic rather than static, it can reliably prevent blade tip contact across varying operational conditions without requiring a fundamentally complex system design
2Adaptability or versatility
If adaptive control settings are implemented, then the adaptability to different flight conditions is improved, but the device complexity increases
Solution Approach 1:
The control allocation module serves multiple functions: it manages clearance control, maintains pitch suitability for desired flight paths, and adapts to various flight conditions (hover, forward flight, reverse flight). By making this single module multi-functional, the system achieves high adaptability without proportionally increasing overall device complexity
Solution Approach 2:
The system adapts to different flight conditions by dynamically changing control parameters (control settings allocated to axis-controlling devices) based on measured flight state and desired flight path. This parameter-based adaptation enables versatility while keeping the underlying control architecture relatively simple
Data Source
AI summary
A flight system for an aircraft and method for controlling a clearance between a first rotor disk and a second rotor disk of an aircraft is disclosed. The flight system includes a sensor for measuring an angle of deviation of at least one of a first rotor disk and a second rotor disk of the aircraft to indicate a clearance between the first rotor disk and the second rotor disk as well as sensors for measuring a flight condition of the aircraft. A control allocation module uses the measured angle of deviation and the flight condition of the aircraft to determine an allocation of control settings to axis-controlling devices of the aircraft to attain a selected pitch of the aircraft, wherein the allocation is based at least on the measured angle of deviation and the flight state of the aircraft.