VTOL UAV Rotor Disk Torque Control and Transition

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Solution Overview

Problem

Current VTOL UAVs face challenges in efficiently transitioning between vertical takeoff and landing and horizontal flight modes, particularly in managing torque and aerodynamic lift, which affects their operational efficiency and versatility.

Innovation Solution

A VTOL UAV design featuring a rotor disk with contra-rotating blades providing zero torque in hover mode and horizontal thrust in level-flight mode, coupled with a flight control system that includes swashplate assembly for cyclic pitch control and retractable wings for aerodynamic lift, enabling efficient takeoff, landing, and mission operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional VTOL aircraft use fixed wings with slip-stream control, then the aircraft can transition between vertical and horizontal flight, but the control precision and torque management become problematic

Engineering Contradiction:
Improvetransition controlVSAvoidtorque control
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The aircraft is divided into functionally independent segments: a main rotor system for vertical flight and torque control, and separate fixed wings for horizontal flight. This segmentation allows each component to specialize in its optimal function without interference, resolving the control precision issues in transition phases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rotor blades are designed with variable pitch capability, allowing dynamic adjustment of blade angle during different flight phases. This dynamic control enables precise torque management during transition from vertical to horizontal flight, eliminating the control imprecision of fixed-wing slip-stream systems.

Inventive Principle:
Principle #15Dynamics

2Force

If VTOL UAVs use conventional rotor designs, then vertical lift can be achieved, but torque reaction reduces operational efficiency

Engineering Contradiction:
Improvevertical thrustVSAvoidoperational efficiency
Core Design Contradiction:
ForceVSProductivity

Solution Approach 1:

A tail rotor is positioned to generate counter-torque that balances the main rotor's torque reaction. This counterweight approach neutralizes the harmful torque effect, allowing the aircraft to maintain stable orientation and improve operational efficiency during vertical flight and transition phases.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The torque reaction from the main rotor, which is normally a harmful effect reducing efficiency, is converted into a useful function by the tail rotor. The tail rotor uses this torque to provide directional control and stability, transforming a disadvantage into a operational advantage.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Speed

If VTOL aircraft require runway for acceleration and deceleration, then traditional flight operations can be performed, but space efficiency and landing versatility are reduced

Engineering Contradiction:
Improveflight speedVSAvoidlanding capability
Core Design Contradiction:
SpeedVSAdaptability or versatility

Solution Approach 1:

The aircraft combines multiple flight capabilities in a single design: vertical takeoff and landing like a helicopter, and horizontal flight like a fixed-wing aircraft. This multi-functionality allows the aircraft to operate from various surfaces including ships, vehicles, and small pads, dramatically increasing landing versatility without sacrificing flight speed capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If UAVs replace pilots for dangerous operations, then pilot safety is improved, but control precision and response time may be reduced

Engineering Contradiction:
Improvepilot safetyVSAvoidcontrol precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

Manual pilot control is replaced with an automated flight control system that uses sensors, gyroscopes, and computer algorithms to manage aircraft attitude and transitions. This mechanical-to-automated substitution maintains high control precision while eliminating pilot exposure to dangerous conditions, improving both safety and control accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 design allows for seamless transition between hover and level-flight modes with reduced torque and enhanced control, improving operational efficiency, speed, and versatility, especially in windy environments and for landing on moving platforms.

Implementation Method 1

a rotor disk configured to provide thrust and a flight control system configured to provide avionic control of the VTOL UAV in a hover mode and in a level-flight mode

Methodology Applied
Scientific EffectAerodynamic lift: Aerofoil

Implementation Method 2

flight control system that includes swashplate assembly for cyclic pitch control

Methodology Applied
Scientific EffectMechanical linkage: Mechanical Advantage

Implementation Method 3

retractable wings for aerodynamic lift, enabling efficient takeoff, landing, and mission operations

Methodology Applied
Scientific EffectAerodynamic lift: Aerofoil

Data Source

PatentEP3347269B1Vertical takeoff and landing (VTOL) unmanned aerial vehicle (UAV)
Publication Date: 2019.07.31 NORTHROP GRUMMAN SYSTEMS CORP
  • EP3347269B1 patent drawingFigure 1~2
  • EP3347269B1 patent drawingFigure 3~4
  • EP3347269B1 patent drawingFigure 5~6

AI summary

One example embodiment includes a vertical takeoff and landing (VTOL) unmanned aerial vehicle (UAV) (12). The VTOL UAV includes a flight control system configured to provide avionic control of the VTOL UAV in a hover mode and in a level-flight mode. The VTOL UAV also includes a body (18) encapsulating an engine and the flight control system. The VTOL UAV further includes a rotor disk (14) coupled to the engine and configured to provide vertical thrust and cyclic pitch control in the hover mode and to provide horizontal thrust for flight during the level-flight mode.