Swashplate-Free Rotorcraft Control via Electric Blade Actuation
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Solution Overview
Problem
Conventional rotorcraft control systems rely on swashplates, which increase weight, drag, and complexity, limit control inputs, and introduce vulnerability, while existing electrically-actuated systems require multiple motors and lack effective decoupling mechanisms, leading to potential catastrophic failures.
Innovation Solution
The implementation of an electrically-actuated collective control system that eliminates the need for a swashplate, using harmonic drive transmissions and redundant electric actuators mounted on the rotor head, allowing for coordinated blade control with reduced weight and backlash, and incorporating electro-mechanical torque decoupling mechanisms to ensure system reliability and maintainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a swashplate is used for collective control, then control functionality is achieved, but weight increases and aerodynamic drag increases
Solution Approach 1:
The patent extracts and eliminates the swashplate from the rotorcraft control system, replacing it with electrically-actuated pitch control mechanisms mounted on the rotor hub. This removal directly addresses the weight and drag penalties associated with traditional swashplate assemblies while maintaining collective pitch control functionality through alternative means.
Solution Approach 2:
The patent substitutes the purely mechanical swashplate system with an electrically-actuated system that uses electric motors and pitch control mechanisms. This replacement eliminates the need for complex mechanical linkages, bearings, and hydraulic systems inherent in traditional swashplates, thereby reducing weight and improving aerodynamic efficiency.
2Reliability
If a swashplate is used for collective control, then control functionality is achieved, but aerodynamic drag increases
Solution Approach 1:
By removing the swashplate from the system, the patent eliminates the source of aerodynamic drag associated with the lower plate, pitch links, and mechanical linkages. The electrically-actuated system operates without these protruding mechanical components, thereby reducing aerodynamic resistance.
Solution Approach 2:
The substitution of mechanical swashplate components with electrically-actuated mechanisms eliminates the need for extensive mechanical linkages that create aerodynamic drag. The electric motors and associated mounting structures present a smaller aerodynamic profile compared to traditional swashplate assemblies.
3Reliability
If a swashplate is used for collective control, then control functionality is achieved, but device complexity increases
Solution Approach 1:
The patent extracts the complex mechanical swashplate assembly from the control system, replacing it with simpler electrically-actuated pitch control mechanisms. This elimination of complex mechanical linkages, bearings, and hydraulic systems directly reduces device complexity while maintaining control functionality.
Solution Approach 2:
The substitution of the mechanical swashplate system with electrically-actuated mechanisms replaces complex mechanical components with simpler electrical systems. Electric motors and electronic control systems generally have fewer moving parts and require less maintenance compared to mechanical swashplate assemblies.
4Reliability
If a swashplate is used for collective control, then control functionality is achieved, but ballistic vulnerability increases
Solution Approach 1:
By removing the swashplate and its associated pitch links from the rotorcraft, the patent eliminates critical mechanical components that are vulnerable to ballistic damage. The electrically-actuated system has fewer exposed mechanical parts that could be damaged by missile attack, flak, or flying debris.
5Adaptability or versatility
If multiple electric actuators are used without decoupling mechanisms, then redundant control is achieved, but system reliability decreases due to potential catastrophic failures
Solution Approach 1:
The patent incorporates decoupling mechanisms that allow individual electric actuators to be isolated from the system before failures can propagate catastrophically. These mechanisms provide a failsafe that cushions against the potential harm of actuator failures, allowing the system to continue operating with reduced but adequate control capability.
Solution Approach 2:
The patent segments the control system into independent electric actuator modules, each capable of being isolated from the others through decoupling mechanisms. This segmentation allows individual actuators to fail without compromising the entire system, as failed actuators can be disconnected while remaining actuators continue to provide control functionality.
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 solution reduces weight, drag, and vulnerability, enhances reliability and maintainability, allows for higher-frequency control inputs, and improves aerodynamics, resulting in improved rotorcraft performance, reduced fuel usage, and increased safety.
Implementation Method 1
Each actuator comprises a harmonic drive transmission with zero backlash
Data Source
AI summary
Multiple redundant harmonic drive motors on a rotor head actuate the angle of attack of rotor blades at the rotor blade roots, providing collective control that, in combination with a system for providing cyclic control on the rotor blades, eliminates the need for a swashplate, thereby advantageously reducing the weight and maintenance cost of a helicopter, increasing its reliability, and reducing its vulnerability to ballistic attack.