Electromechanical Hinge-Line Rotary Actuator Design
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Solution Overview
Problem
Conventional electromechanical hinge-line rotary actuators for flight-control applications suffer from inefficiencies in packaging, low power density, and high inertia, which affect the responsiveness and reliability of aircraft systems, particularly in thin-wing aircraft where space and size are limited.
Innovation Solution
The design features a motor with a rotor positioned outside and a stator inside, directly coupled to a drive member, and an output arm with a harmonic circular spline, reducing the number of components and eliminating the need for a precision-machined housing, resulting in a more compact, high-power-density actuator with lower inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional motor with frame and rotor is used, then the motor is protected and easy to manufacture, but the actuator has low power density and high inertia
Solution Approach 1:
The patent removes the motor frame (housing) from the conventional motor design, extracting only the essential functional components (stator, rotor, windings) while eliminating the protective enclosure. This extraction enables direct integration of the motor into the actuator assembly, reducing overall inertia and packaging volume while maintaining operational reliability through direct coupling to the drive member.
Solution Approach 2:
The patent merges the motor assembly directly with the drive member by coupling the rotor directly to the drive member without intermediate shafts or couplings. This merging eliminates additional components and reduces the moment of inertia, thereby improving power density while maintaining reliable power transmission through direct mechanical coupling.
2Manufacturing precision
If a precision-machined housing is used to align motor and gear set, then alignment is accurate, but packaging efficiency is reduced
Solution Approach 1:
The patent removes the precision-machined housing entirely, extracting the alignment function from a separate structural component and integrating it directly into the motor-gear interface. The motor is positioned and aligned through direct mounting features on the actuator body, eliminating the housing as a separate packaging element and improving space efficiency.
Solution Approach 2:
The patent combines the alignment function with the motor mounting structure itself, rather than relying on a separate precision housing. The motor is directly coupled to the drive member with alignment achieved through integrated mounting features, merging multiple functions (support, alignment, coupling) into a single integrated assembly that improves packaging efficiency.
3Force
If higher gear ratios are used to compensate for limited torque, then torque requirement is met, but reflected inertia increases significantly
Solution Approach 1:
The patent changes the motor's operational parameters by increasing its rotational speed to compensate for the limited torque output. By operating the motor at higher speeds with direct coupling to the drive member, the system achieves the required power output (P = T × ω) without relying on high gear ratios, thereby minimizing reflected inertia while meeting torque requirements through speed multiplication.
4Force
If motor diameter is increased to provide more torque, then torque output improves, but the actuator cross-section increases
Solution Approach 1:
The patent changes the motor's operational parameters by increasing rotational speed rather than physical dimensions. By operating at higher speeds with direct coupling, the motor delivers required power output without increasing diameter, maintaining a compact actuator cross-section suitable for thin-wing aircraft applications.
Solution Approach 2:
The patent replaces the conventional mechanical approach of increasing motor size for more torque with an electromechanical approach using high-speed motor operation and direct coupling. This substitution allows torque requirements to be met through speed-torque characteristics rather than physical scaling, maintaining compact dimensions.
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 configuration enhances power density, performance, and reliability by minimizing inertia and component count, enabling higher forces within the same cross-section and accommodating various applications, while maintaining a direct drive load path without a drive shaft.
Implementation Method 1
The motor has a rotor configured toward an outside of the motor and directly coupled to an input of the drive member
Data Source
AI summary
An electromechanical rotary actuator includes a drive member, a motor disposed inside and directly coupled to the drive member, and an output arm. The motor has a rotor configured toward an outside of the motor and directly coupled to an input of the drive member and a stator configured toward an inside of the motor and positioned inside the rotor. The output arm is disposed about the motor and is drivably connected to the drive member. The output arm defines an arcuate opening.