Rocket Cluster Center of Gravity Control via Radial Motor Ejection

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Solution Overview

Problem

Ballistic missiles and rockets face challenges in maintaining precise control of their center of gravity during course corrections, leading to errors due to changes in mass distribution caused by firing motors and burning fuel.

Innovation Solution

A flight vehicle equipped with radial motors and roll thrusters, along with ejectors, is designed to control the center of gravity by selectively firing and ejecting these components to maintain precise trajectory adjustments and balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If motors are fired and fuel is burned to enable course corrections, then the flight vehicle can adjust its trajectory, but the center of gravity continually changes causing unbalance and error in course corrections

Engineering Contradiction:

Improvetrajectory adjustment capabilityVSAvoidcenter of gravity control precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The flight vehicle is divided into modular components including multiple radial motors that can be independently fired and ejected. This segmentation allows selective mass adjustment by ejecting specific motors to counterbalance the center of gravity changes caused by fuel consumption during course corrections

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically changes the mass distribution parameter by selectively ejecting radial motors based on real-time center of gravity calculations. This parameter change compensates for the continuous mass change from fuel burning, maintaining precise center of gravity control throughout the flight trajectory adjustments

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If additional mass is added to correct for unbalancing effects, then center of gravity control is improved, but the overall weight of the flight vehicle increases

Engineering Contradiction:

Improvecenter of gravity control precisionVSAvoidflight vehicle weight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

Instead of adding mass to correct balance, the system extracts (ejects) specific radial motors that have completed their thrust function. This removal of mass is strategically used to counterbalance the center of gravity shift caused by fuel consumption, achieving balance correction without adding weight

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The system discards spent radial motors after they have served their purpose in trajectory adjustment. This discarding action serves the dual purpose of mass reduction and center of gravity control, eliminating the need for additional ballast mass while maintaining flight balance

Inventive Principle:

Principle #34Discarding and recovering

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

This solution enables accurate and efficient course corrections, allowing the flight vehicle to maintain precise control over its center of gravity, improving intercept accuracy and reducing the need for additional mass to correct for unbalancing effects.

Implementation Method 1

Radial motors are coupled to the fuselage retaining structure and arranged about a central longitudinal axis of the flight vehicle, each radial motor for expelling radial thrust radially outwardly in respect to the flight vehicle

Methodology Applied

Scientific EffectThrust: Rocket

Implementation Method 2

Roll thrusters are operatively coupled with the radial motors and are coupled to the fuselage retaining structure, the roll thrusters for providing a roll moment of the flight vehicle about the central longitudinal axis

Methodology Applied

Scientific EffectRoll moment: Torque

Implementation Method 3

Ejectors are operatively coupled to the radial motors, the ejectors for ejecting the radial motors from the flight vehicle to further maintain control of the center of gravity

Methodology Applied

Scientific EffectEjection: Rocket

Data Source

PatentUS9377279B2Rocket cluster divert and attitude control system

Publication Date: 2016.06.28 RAYTHEON CO

AI summary

A flight vehicle includes a nose portion, a fuselage retaining structure aft of the nose portion, and an axial motor for expelling axial thrust along a longitudinal axis of the flight vehicle. Radial motors are coupled to the retaining structure and axisymmetrically arranged about the axial motor. Each radial motor is configured to expel radial thrust radially outwardly in respect to the flight vehicle. Roll thrusters are operatively coupled with the radial motors and coupled to the fuselage retaining structure. The roll thrusters are configured to provide a roll moment of the flight vehicle about a central longitudinal axis of the flight vehicle. Ejectors are operatively coupled to the radial motors, and a controller is operatively coupled to the radial motors and the ejectors. The controller is configured to selectively fire and selectively eject the radial motors to maintain relative centering of a center of gravity of the flight vehicle.