Pivoting Thrust Subunits for Stable Hover Flight Control

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Solution Overview

Problem

As the size of an aircraft increases, its kinematic performance is reduced due to increased moments of inertia, and it becomes difficult to maintain stability and quickly return to its original attitude when disturbed, such as by gusts during hovering, leading to reduced flight stability.

Innovation Solution

A flight vehicle configuration that allows the direction of thrust to be changed while maintaining a fixed attitude, eliminating the need for or reducing the size of actuators specialized for pivoting thrust generating subunits, simplifying construction, reducing weight, and increasing flexibility in thrust generation mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the size of the aircraft body is increased, then the thrust generating capacity is improved, but the kinematic performance is reduced due to increased moments of inertia

Engineering Contradiction:
Improvethrust generating capacityVSAvoidkinematic performance
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The aircraft is divided into a main body and multiple independent thrust generating subunits. Each subunit can be independently controlled to generate thrust, allowing the system to achieve high thrust capacity without requiring a large monolithic body structure. This segmentation enables better kinematic performance by distributing the mass and reducing the moment of inertia of the main body.

Inventive Principle:
Principle #1Segmentation

2Force

If the aircraft body size is increased, then the thrust generating capacity is improved, but the flight stability is reduced when disturbed by external factors

Engineering Contradiction:
Improvethrust generating capacityVSAvoidflight stability
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The thrust generating subunits are designed with pivot joints that allow them to dynamically adjust their orientation. When the aircraft experiences disturbances such as gusts, the control system can rapidly reposition these subunits to counteract the disturbance and restore stable flight. This dynamic adjustment capability enhances flight stability without requiring a larger body.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If actuators are added to pivot thrust generating subunits, then the direction of thrust can be changed, but the device complexity and weight increase

Engineering Contradiction:
Improvethrust direction controlVSAvoidactuator system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The pivot joints serving as connection means between the main body and thrust generating subunits fulfill multiple functions: they mechanically connect the subunits to the main body, provide pivotability for thrust direction control, and serve as the mounting structure for the subunits. This multi-functionality eliminates the need for separate actuators, reducing device complexity and weight while maintaining full thrust direction control capability.

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

Data Source

PatentEP3795470B1Flight vehicle and method of controlling flight vehicle
Publication Date: 2023.12.06 KAWASAKI JUKOGYO KK
  • EP3795470B1 patent drawingFigure 1
  • EP3795470B1 patent drawingFigure 2
  • EP3795470B1 patent drawingFigure 3

AI summary

Provided is a flight vehicle including: a main body (1); a thrust generating unit (6) including one or more thrust generating subunits (3); and one or more joints (5) associated respectively with the one or more thrust generating subunits, the or each joint coupling the associated thrust generating subunit to the main body and permitting the associated thrust generating subunit to freely pivot relative to the main body along a circumference of a circle centered on a first pivot axis (R) intersecting a direction of thrust generated by the associated thrust generating subunit. The or each thrust generating subunit includes a plurality of thrust generators (9), each thrust generator being configured to change a magnitude of thrust to be generated independently of the other thrust generator or generators. In the or each thrust generating subunit, a first thrust generator group (G1) constituted by one or more of the thrust generators is arranged to generate thrust that induces a torque (τ1) urging the thrust generating subunit in one direction along the circumference of the circle centered on the first pivot axis, and a second thrust generator group (G2) constituted by other one or more of the thrust generators is arranged to generate thrust that induces a torque (τ2) urging the thrust generating subunit in the opposite direction along the circumference of the circle centered on the first pivot axis (R).