Trajectory-Based Rotor Blade Pitch Control for Vibration Reduction
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Solution Overview
Problem
Existing rotorcraft control systems face limitations in achieving precise blade pitch control, particularly with swashplate-based systems, which struggle to accurately control higher harmonics and individual blades, leading to inefficiencies in vibration reduction, acoustic noise management, and control power optimization.
Innovation Solution
Implementing trajectory-based control algorithms that utilize electronic rotor blade controllers with motor drive circuits, communication circuits, and processors to accurately track and achieve desired blade pitch trajectories, including higher-order derivative terms, allowing for precise control of blade pitch, twist, or control surface position as a function of azimuth or time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If swashplate-based control systems are used, then collective and cyclic pitch control can be achieved, but higher harmonic control and individual blade control are limited
Solution Approach 1:
The patent divides the control system into multiple independent actuators, each capable of controlling individual blades or specific harmonic components. This segmentation allows independent control of each blade's pitch trajectory, enabling higher harmonic content and individual blade control while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
The patent introduces control in additional dimensions by enabling independent control of multiple harmonics (fundamental, second harmonic, third harmonic) and individual blade phases. This transforms the traditional two-dimensional swashplate control (collective and cyclic) into a multi-dimensional control space, allowing sophisticated pitch trajectory manipulation for vibration reduction and noise control.
2Object-affected harmful factors
If higher harmonic control is implemented using swashplate, then vibration reduction can be achieved, but control input power and acoustic noise management are limited
Solution Approach 1:
The patent implements feedback control mechanisms where sensors monitor blade pitch position, rotor vibration levels, and acoustic noise. This feedback information is fed to the control algorithm, which adjusts the actuator commands in real-time to optimize vibration reduction while minimizing control input power and acoustic noise, creating a closed-loop system that efficiently manages energy and harmful outputs.
Solution Approach 2:
The patent dynamically changes control parameters including harmonic content, phase angles, and actuator activation timing based on operating conditions. By adaptively adjusting these parameters, the system optimizes vibration reduction effectiveness while minimizing control input power requirements and acoustic noise generation across different flight regimes.
3Measurement precision
If individual blade control is implemented, then precise pitch trajectory control is achieved, but device complexity increases
Solution Approach 1:
The patent designs actuators and control algorithms that serve multiple functions: controlling individual blade pitch, generating higher harmonic content, reducing vibration, and managing acoustic noise. This multi-functionality reduces the need for separate dedicated systems for each function, thereby achieving precise blade pitch control without proportionally increasing overall device complexity.
Data Source
AI summary
An aircraft uses trajectory-based control algorithms for blade pitch (or twist). This approach greatly enhances the ability of the actuator to accurately achieve the desired blade pitch and to track the commanded pitch position. An actuator includes an electronic rotor blade controller that converts communicated or desired changes in pitch (or similar parameter) to actual physical effects that match the desired changes as closely as possible. The controller preferably includes a motor drive circuit, such as an h-bridge, a communication circuit for connection to external commands, and a processor with associated enabling circuitry (e.g. memory, I/O) to coordinate and implement the control.