Taxiing Thrust Control to Prevent Helicopter Lift-Off

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Solution Overview

Problem

Aerial vehicles, such as helicopters, face challenges during ground taxiing due to unintentional lift-offs caused by errant control inputs or environmental conditions, leading to unstable operations and potential damage to landing gear.

Innovation Solution

A data processing system that utilizes sensors to detect differences in forces applied to ground contact points and adjusts thrust components of rotors or propellers to maintain stability and prevent lift-off, incorporating wind speed and control inputs to ensure controlled taxiing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If control inputs are increased to improve directional control during taxiing, then lateral thrust and directionality are improved, but unintentional lift-off occurs due to excess vertical thrust

Engineering Contradiction:
Improvelateral thrustVSAvoidground contact stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The system continuously monitors vertical load on ground contact points using sensors and feeds this information back to the control system. When load changes indicate potential lift-off, the system automatically adjusts rotor/propeller thrust to maintain ground contact, creating a closed-loop control that prevents unintentional lift-off while allowing effective directional control

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system dynamically changes thrust parameters (vertical and lateral components) based on real-time sensor data. By adjusting rotor/propeller pitch and/or speed, the system modulates thrust vectors to maintain optimal ground contact forces during taxiing operations, preventing both lift-off and excessive ground force

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If manual control precision is increased to prevent unintentional lift-off, then ground contact stability is improved, but control complexity and operator burden increase

Engineering Contradiction:
Improveground contact stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The control system performs self-correction by automatically detecting load changes on ground contact points and adjusting thrust accordingly. This autonomous stabilization reduces the pilot's workload and eliminates the need for complex manual control techniques, as the system self-regulates to prevent unintentional lift-off during taxiing

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If thrust adjustment responsiveness is increased to prevent unstable lift-off, then ground contact stability is improved, but control system complexity and response time requirements increase

Engineering Contradiction:
Improvelift-off stabilityVSAvoidcontrol responsiveness
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The control system continuously monitors ground contact loads and detects trends before actual lift-off occurs. By identifying preliminary signs of vertical thrust excess (load reduction trends), the system proactively adjusts thrust parameters to prevent unstable lift-off, rather than reacting after lift-off has already occurred

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Real-time feedback from load sensors enables the control system to detect and respond to thrust imbalances immediately. The continuous monitoring and closed-loop control create rapid response to load changes, stabilizing ground contact by adjusting thrust in direct response to detected conditions

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4582339A1Thrust control for ground navigation of aerial vehicles
Publication Date: 2025.07.09 LOCKHEED MARTIN CORP
  • EP4582339A1 patent drawingFigure 1
  • EP4582339A1 patent drawingFigure 2
  • EP4582339A1 patent drawingFigure 3

AI summary

Aerial navigation is disclosed. A system can detect a difference between forces applied to a plurality of ground contact points of an aerial vehicle taxiing on a ground surface. The system can determine an adjustment to a vertical component of a thrust. The thrust can be produced by at least one of a rotor or a propeller of the aerial vehicle to reduce the difference between the forces applied to the plurality of ground contact points of the aerial vehicle. The system can generate a control output to cause the at least one of the rotor or the propeller to adjust the vertical component of the thrust to reduce the difference between the forces.