Rotor Assembly Non-Back Drive for Stable Blade Pitch Control
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Solution Overview
Problem
Existing rotor assemblies in eVTOL aircraft face challenges in maintaining stability and thrust control, particularly in the event of drive unit failures, which can compromise flight stability and safety.
Innovation Solution
The rotor assembly incorporates a non-back drive part that prevents the transfer of forces from the swash plate to the drive unit, allowing for independent adjustment of blade pitch angles and maintaining stability even in the event of drive unit failures, using a non-back drive mechanism with a worm and worm gear configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional drive mechanism is used that allows force transfer from swash plate to drive unit, then the drive unit can be controlled by swash plate movement, but force from external sources can propagate to the drive unit causing instability
Solution Approach 1:
The drive mechanism is segmented into two distinct functional parts: a non-back drive part that prevents force feedback from swash plate to drive unit, and a back drive part that allows controlled force transfer for normal operation. This segmentation isolates the drive unit from external force propagation while maintaining controllability.
Solution Approach 2:
A non-back drive mechanism acts as an intermediary between the swash plate and drive unit. This intermediary component selectively blocks force transmission in the unwanted direction (from swash plate to drive unit) while permitting motion control in the desired direction (from drive unit to swash plate).
2Reliability
If the swash plate is directly connected to the drive unit, then control is simple and direct, but external forces can affect the drive unit and compromise stability
Solution Approach 1:
The connection between swash plate and drive unit is divided into two functional segments: a non-back drive part for stability (blocking external forces) and a back drive part for control (allowing commanded motion). This segmentation maintains ease of operation while improving reliability.
Solution Approach 2:
Different parts of the connection mechanism have different mechanical properties: the non-back drive part has high stiffness in one direction (blocking forces) while the back drive part allows controlled motion. This local differentiation of mechanical properties achieves both stability and controllability.
3Reliability
If a non-back drive mechanism is introduced to prevent force transfer, then stability is improved, but the device complexity increases
Solution Approach 1:
The protection mechanism is segmented into modular components: non-back drive part and back drive part. This modular segmentation makes the complex mechanism more manageable, maintainable, and potentially manufacturable while achieving the stability benefit.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures consistent blade pitch angles and thrust, enhancing stability and safety by preventing the propagation of external forces to the drive unit, thereby maintaining flight stability and performance.
Implementation Method 1
using a non-back drive mechanism with a worm and worm gear configuration
Data Source
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AI summary
A rotor assembly (10) includes a main shaft (100); at least one blade (200) disposed along a circumference of the main shaft; a swash plate unit (300) disposed to penetrate the main shaft, connected to at least one of the blades, and configured to move along the main shaft; and a drive unit (420) configured to control a position of the swash plate unit (300), wherein the swash plate unit and the drive unit are connected to each other through a non-back drive part (500) which does not allow force to be transferred to the drive unit.