Rotor Track and Balance Linear Optimization
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Solution Overview
Problem
Existing rotor track and balance methods for rotary-wing aircraft primarily address one per rev vibration frequencies, neglecting higher harmonic vibrations, which results in suboptimal reduction of vibrations and structural damage, crew fatigue, and limited maximum forward speed.
Innovation Solution
A heuristic-based linear optimization algorithm that determines initial and subsequent error values between desired and measured vibration levels, combines disturbance signals with flight responses, and predicts adjustment solutions for pitch control rods, trim tabs, and hub weights to minimize vibrations across multiple harmonic frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If control adjustments are based on one per rev frequency only, then one per rev vibration is reduced, but higher harmonic vibrations are neglected and overall vibration reduction is not optimal
Solution Approach 1:
The optimization algorithm is designed to handle multiple harmonic frequencies (1/rev, 2/rev, 3/rev, etc.) simultaneously through a unified mathematical framework. The cost function aggregates vibration errors across all harmonic frequencies, and the control adjustments are computed to minimize the total vibration across the entire frequency spectrum, making the system universally applicable to all harmonic components rather than addressing each frequency separately
Solution Approach 2:
The patent extends the optimization from a single-frequency (1/rev) dimension to a multi-dimensional frequency space by incorporating higher harmonic frequencies into the error calculation. The algorithm operates in a expanded parameter space that includes multiple frequency components, transforming the problem from one-dimensional to multi-dimensional optimization, thereby achieving comprehensive vibration reduction across all harmonic frequencies
2Ease of manufacture
If traditional rotor track and balance methods are used, then implementation is simple, but vibration reduction effectiveness is limited due to neglect of higher harmonics
Solution Approach 1:
The system implements an iterative feedback optimization process where vibration measurements from multiple harmonic frequencies are fed back into the cost function, which then generates updated control adjustments. The algorithm repeatedly refines the control parameters by comparing predicted vibrations with actual measurements, using the error feedback to progressively minimize vibrations across all frequencies until convergence is achieved
Solution Approach 2:
The patent performs preliminary computation of the optimization solution by pre-calculating the relationship between control adjustments and vibration responses through a linearized model. The algorithm computes the optimal control adjustments in advance based on the cost function and system model, allowing the control system to be configured before actual operation, thereby simplifying implementation while achieving optimal vibration reduction
Data Source
AI summary
A method for reducing vibrations in an airframe of an aircraft includes determining, with a processor, information indicative of an initial error value between a desired vibration level and a measured vibration level in the airframe; determining, with the processor, an initial adjustment solution for the aircraft in response to the determining of the information for the initial error value; receiving, with the processor, information indicative of a flight response to the initial adjustment solution; combining, with the processor, disturbance signals indicative of vibration noise with the information for the flight response; determining, with the processor, a subsequent error value between the desired vibration level and a subsequent measured vibration level; and determining, with the processor, a predicted adjustment solution in response to the determining of the subsequent error value.