Flight Control System Using Actuator Data for State Estimation

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Solution Overview

Problem

Aerial vehicles face challenges in accurately determining their position and airframe state data when inertial measurement units fail or become unreliable, particularly during high-dynamic events like boost phases, leading to potential miss-targeting and increased costs due to redundant systems.

Innovation Solution

An airframe state data estimation method using actuator deflection and current measurements to estimate airframe states, eliminating the need for redundant inertial measurement units by employing an airframe state data estimation unit that generates estimated airframe state data, which can be used in place of or to verify data from inertial measurement units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant inertial measurement units are added to provide backup navigation capability, then reliability is improved, but weight and cost increase

Engineering Contradiction:

Improvenavigation reliabilityVSAvoidvehicle weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the mechanical sensor-based inertial measurement system with a computational model that uses flight dynamics equations. The system substitutes physical redundancy (multiple IMUs) with mathematical redundancy (flight dynamics model), eliminating the need for additional mechanical sensors while maintaining navigation reliability through model-based state estimation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a virtual copy of the inertial measurement functionality through a flight dynamics model that replicates the navigation calculation capabilities. Instead of physically copying the IMU hardware, the system uses software-based flight dynamics equations to generate equivalent navigation state information, providing redundancy without additional physical components.

Inventive Principle:

Principle #26Copying

2Reliability

If redundant inertial measurement units are added to provide backup navigation capability, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvenavigation reliabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive redundant hardware with a computational approach using flight dynamics models. By substituting physical IMU units with mathematical calculations based on available sensor data and aerodynamic models, the system eliminates manufacturing costs associated with purchasing, integrating, and calibrating additional inertial measurement units.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses a software-based flight dynamics model that is computationally inexpensive to execute. Rather than investing in expensive redundant hardware, the system employs lightweight computational algorithms that can be implemented through software, significantly reducing manufacturing and deployment costs while providing the same reliability function.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Loss of information

If inertial measurement units are used during high-dynamic events, then position tracking is maintained, but measurement reliability deteriorates due to sensor range limitations

Engineering Contradiction:

Improveposition information continuityVSAvoidsensor reliability

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The patent changes the approach from direct sensor measurement to model-based estimation. During high-dynamic events, instead of relying on sensors that may exceed their measurement ranges, the system uses flight dynamics models that can handle extreme conditions through mathematical relationships. The model adjusts state estimates based on aerodynamic forces and vehicle dynamics, maintaining reliability when physical sensors fail.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces a flight dynamics model as an intermediary between raw sensor data and navigation state estimation. This intermediary layer processes sensor inputs through aerodynamic and dynamic equations, filtering out measurement errors and providing reliable state estimates even when sensors operate near or beyond their specified ranges during high-g maneuvers.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8346408B2Fault tolerant flight control system

Publication Date: 2013.01.01 THE BOEING CO

AI summary

A method, apparatus, and computer program product for identifying a number of air states for a vehicle. A deflection of a control surface associated with an actuator is identified to form an identified deflection. A current in the actuator is identified to form a measured current. The number of air states for the vehicle is estimated using the identified deflection and the measured current.