Convertiplane Rotor Control System for Pitch and Stability

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Solution Overview

Problem

Current convertiplane designs face challenges in reducing overall dimensions for pitch control systems while optimizing rotor disc tilting in both helicopter and airplane configurations, and enhancing static sideways stability and minimizing blade interference.

Innovation Solution

The design incorporates a control system with a rotating swashplate and non-rotating swashplate connected by a compass linkage, allowing for adjustable tilt of the rotor disc about orthogonal axes, using a single actuator and rod system to vary collective and cyclic pitch, reducing complexity and dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a traditional pitch control system with multiple actuators is used, then the rotor disc tilting control is reliable, but the overall dimensions and constructional complexity increase

Engineering Contradiction:

Improvepitch control system complexityVSAvoid rotor disc tilting control reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent combines multiple pitch control functions into a single actuator system. The push-pull rod integrates both collective pitch control (through translation along the first axis) and cyclic pitch control (through oscillation about the fulcrum), eliminating the need for separate actuators for each function while maintaining full control capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single actuator system performs multiple functions: it controls collective pitch by translating the swashplate along the first axis, controls cyclic pitch by oscillating the swashplate about the fulcrum, and can control rotor disc tilting in both helicopter and aeroplane configurations, making it a universal control solution

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Stability of the object's composition

If the rotor disc tilting is optimized for helicopter configuration, then the static sideways stability increases, but the tilting flexibility in aeroplane configuration decreases

Engineering Contradiction:

Improvestatic sideways stabilityVSAvoidrotor disc tilting flexibility

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The system dynamically adapts its rotor disc tilting characteristics based on operational configuration. In helicopter mode, the rotor discs are tilted laterally by a first angle to maximize static sideways stability. In aeroplane mode, the same system tilts the rotor discs longitudinally by a second angle to optimize forward flight performance, with the tilting mechanism capable of continuous adjustment between these states

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the rotor disc tilting system based on configuration. The tilting angle parameters are optimized for each mode: a first tilting angle range for helicopter configuration to enhance lateral stability, and a second tilting angle range for aeroplane configuration to enhance longitudinal control and performance

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the blade flapping angle is increased, then the rotor disc tilting range increases, but the blade interference with half-wings increases

Engineering Contradiction:

Improve rotor disc tilting rangeVSAvoidblade interference with half-wings

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The rotor system is divided into independent half-discs, each controlled by its own swashplate and actuator system. This segmentation allows each rotor to be tilted and controlled independently, enabling the rotor discs to be positioned optimally relative to the half-wings to minimize interference while maintaining full tilting range

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11472543B2Convertiplane and control method thereof

Publication Date: 2022.10.18 LEONARDO SPA

AI summary

A convertiplane is described that has a fuselage with a first axis, a pair of half-wings, and a pair of rotors arranged on mutually opposite ends of the half-wings. The rotor comprises a mast hinged on a second axis and a plurality of blades hinged on the mast. The mast of the rotor can be tilted with the second axis about a third axis transversal to the second axis and with respect to the fuselage to transform the convertiplane between a helicopter mode and an aeroplane mode; the second axis is transversal to the first axis in the helicopter mode and is parallel to the first axis in the aeroplane mode. The rotor disc can be tilted about a fourth axis. The rotor comprises control means for controlling the cyclic pitch and collective pitch of the blades comprising: a first actuator controllable to vary the collective pitch, a second actuator controllable to vary the tilt of the rotor disc about the fourth axis and a rod movable to alter the tilt of the corresponding rotor disc about a fifth axis according to the mode of the convertiplane.