Hovering Aircraft Rotor Torque Estimation Without Physical Sensors
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Solution Overview
Problem
Existing methods for estimating rotor torques in hovering aircraft are unreliable and costly due to the use of physical sensors, and they fail to accurately account for differences in rotor torques during various maneuvers.
Innovation Solution
A method that estimates rotor torques by calculating a first component based on engine torque and mechanical losses, and a second component based on collective pitch angle differences, allowing for accurate estimation without physical sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical sensors are used to directly measure rotor torques, then measurement reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces physical torque sensors with a computational estimation system that calculates rotor torques using engine torque measurements, transmission efficiency models, and rotor performance parameters. This substitution eliminates the need for complex mechanical sensors while maintaining measurement capability through mathematical modeling and data processing.
Solution Approach 2:
The patent introduces an intermediary computational system that acts as a mediator between engine torque measurements and rotor torque determination. Instead of directly measuring rotor torques with sensors, the system uses engine torque as an intermediary parameter and applies transmission efficiency factors to estimate rotor torques, thereby avoiding direct sensor installation on rotors.
2Measurement precision
If physical sensors are used to directly measure rotor torques, then measurement precision is improved, but installation and maintenance costs increase
Solution Approach 1:
The patent replaces expensive physical torque sensors with a computational estimation approach that uses readily available engine torque measurements and transmission efficiency data. This substitution significantly reduces installation and maintenance costs while providing sufficient measurement precision for control applications.
Solution Approach 2:
The patent creates a virtual model of the transmission system that replicates the relationship between engine torque and rotor torque. This computational copy allows accurate torque estimation without requiring physical sensors on the rotors, thereby eliminating installation and maintenance costs associated with hardware sensors.
3Device complexity
If rotor torques are estimated by equally apportioning total available engine torque, then device complexity is reduced, but measurement precision deteriorates when rotor torques are significantly different
Solution Approach 1:
The patent applies local quality by allowing each rotor's torque estimation to be individually adjusted based on its specific operational characteristics, such as collective pitch angle and rotor speed. Instead of uniformly distributing torque, the system calculates each rotor's share based on its local performance parameters, improving accuracy when rotors operate under different conditions.
Solution Approach 2:
The patent introduces dynamics by making the torque distribution ratio variable rather than fixed. The system continuously adjusts the torque allocation to each rotor based on real-time operational parameters such as collective pitch angles and rotor speeds, enabling accurate torque estimation even when rotors experience significantly different loading conditions.
Data Source
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AI summary
A method for estimating rotor torques (TQmast1, TQmast2,…,TQmastN) of an aircraft (1; 1'; 1'') capable of hovering and comprising a plurality of rotors (31, 32; 33', 34'), which are rotatable under the action of respective rotor torques (TQmast1, TQmast2,…,TQmastN); and an engine (21, 22; 23', 24'), which is operatively connected to the rotors (31, 32; 33' 34') to provide them with an engine torque (TQeng1, TQeng2,…,TQengM). Each rotor (31, 32; 33', 34') comprises a hub (7) and a plurality of blades (8) articulated on the respective hub (7) in such a way that respective collective pitch angles (θ1COLL, θ2COL,…, θNCOLL) are adjustable. The method comprises the steps of i) calculating a symmetric component (TQmastSYM) on the basis of the engine torque (TQeng1, TQeng2,…,TQengM); ii) receiving a signal associated with collective pitch angles (θ1COLL, θ2COLL,…, θNCOLL); iii) calculating an asymmetric component (TQmastASYM1, TQmastASYM2,…, TQmastASYMN) on the basis of a pitch angle difference (Δθ1COLL, ΔθCOLL2,…, ΔθCOLLN) between the collective pitch angles (θ1COLL, θ2COL,…, θNCOLL); and iv) calculating each rotor torque (TQmast1, TQmast2,…,TQmastN) as the algebraic sum of the symmetric component (TQmastSYM) and the respective asymmetric component (TQmastASYM1, TQmastASYM2,…, TQmastASYMN).