Harmonic Swashplate Actuation for Helicopter Vibration Reduction
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Solution Overview
Problem
Rotary blade aircrafts experience significant vibrations during flight, which current technologies fail to effectively mitigate, leading to reduced pilot control and comfort.
Innovation Solution
A harmonic control actuator system comprising a housing, electric motors, ring gear, planetary gear, and eccentric sleeve, which drives a swashplate assembly to reduce vibrations by independently controlling the movement of rotor blades based on measured airframe vibrations, using sensors and a control processor to determine desired blade movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a hydraulic control servo is used to move the swashplate assembly, then the rotor blades can be controlled for basic flight operations, but vibrations at selected frequencies cannot be effectively reduced
Solution Approach 1:
The control system is segmented into two independent components: a hydraulic control servo for basic flight operations and a harmonic control actuator for vibration reduction. This segmentation allows each component to specialize in its specific function without interfering with the other, enabling effective vibration reduction while maintaining pilot control capability.
Solution Approach 2:
The harmonic control actuator serves as an intermediary device between the hydraulic control servo and the swashplate assembly. It independently adjusts the swashplate position at selected frequencies to counteract vibrations, while the hydraulic servo continues to handle primary control functions.
2Object-affected harmful factors
If the swashplate assembly is moved to reduce vibrations, then comfort is improved, but the complexity of the control system increases
Solution Approach 1:
The harmonic control actuator combines multiple functions into a single device: it includes an electric motor, gear train, and eccentric mechanism integrated in one assembly. This merging reduces the overall system complexity compared to using separate components for each function.
Solution Approach 2:
The harmonic control actuator is designed as a multi-functional device that can operate independently to reduce vibrations at selected frequencies while working in conjunction with the hydraulic control servo. This universality allows a single added component to address vibration reduction across different flight conditions without requiring multiple specialized systems.
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
The system effectively reduces vibrations at specific frequencies, enhancing pilot control and comfort by oscillating rotor blades to counteract harmonic vibrations, thereby improving flight stability and maneuverability.
Implementation Method 1
an electric motor coupled to the housing... The crankshaft is driven by the electric motor
Implementation Method 2
The planetary gear includes an eccentric sleeve. The crankshaft is driven by the electric motor to drive the planetary gear... an output member coupled to the eccentric sleeve to be driven along an output path
Data Source
AI summary
A rotary blade aircraft includes an airframe, a rotor shaft driven about a rotor axis, and a plurality of rotor blades driven by the rotor shaft about the rotor axis. The rotary blade aircraft includes a swashplate assembly coupled to the plurality of rotor blades. The swashplate assembly is operable to move the plurality of rotor blades about a respective longitudinal axis. The rotary blade aircraft includes a hydraulic control servo coupled between the airframe and the swashplate assembly. The hydraulic control servo is operable to move the swashplate assembly relative to the rotor axis. The rotary blade aircraft includes a harmonic control actuator coupled between the airframe and the swashplate assembly. The harmonic control actuator is operable independently relative to the hydraulic control servo to move the swashplate assembly relative to the rotor axis to reduce vibration at selected frequencies in the airframe.