Aircraft Control Column Feedback With Simulated Inertia and Stability

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Solution Overview

Problem

Aircraft control devices with effort feedback have limited stability margins, particularly when stiffness is high compared to damping, and fail to simulate inertia, requiring additional sensors that complicate and increase the cost of the control device.

Innovation Solution

A method for controlling an aircraft control device that calculates torque based on angular position, speed, and acceleration using a mechanical connection to restore stiffness, damping, and inertia efforts, utilizing a simple position sensor to provide feedback to the user.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If effort feedback is implemented using a motor connected to the stick, then artificial effort (stiffness and damping) can be restored, but stability margins are very limited when stiffness type effort is high compared to damping type effort

Engineering Contradiction:

Improveartificial effortVSAvoidstability margins

Core Design Contradiction:

ForceVSStability of the object's composition

Solution Approach 1:

The patent changes the control parameters by introducing inertia type effort in addition to stiffness and damping type efforts. The control law is modified to include a term proportional to angular acceleration (inertia effort), which allows the system to maintain higher stability margins even when stiffness effort is high. This parameter expansion from two (stiffness, damping) to three (stiffness, damping, inertia) resolves the stability limitation.

Inventive Principle:

Principle #35Parameter changes

2Force

If effort feedback is implemented to restore stiffness and damping, then artificial effort can be felt by the user, but the user cannot feel an inertia type effort which represents the inertia of the aircraft

Engineering Contradiction:

Improveartificial effortVSAvoideffort types

Core Design Contradiction:

ForceVSAdaptability or versatility

Solution Approach 1:

The patent makes the control system multi-functional by enabling it to generate three distinct types of artificial efforts (stiffness, damping, and inertia) using a single motor and position sensor configuration. The universal control law combines all three effort types, allowing the system to adapt to different flight conditions and provide comprehensive tactile feedback representing the full dynamics of the aircraft.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Force

If an effort sensor is added to provide effort information for servo-control, then effort feedback can be restored, but the control device becomes more complex, more expensive, and has increased risk of failure

Engineering Contradiction:

Improveeffort feedbackVSAvoidcontrol device complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical effort sensor with a computational approach. Instead of measuring effort directly with a sensor, the system calculates the required effort feedback through a control law that processes position and acceleration information. This substitution eliminates the need for additional mechanical sensors, reducing complexity, cost, and failure risk while maintaining the effort feedback function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If only a position sensor is used to determine angular position, then the control device is simpler, but it cannot provide complete effort feedback including inertia without additional sensors

Engineering Contradiction:

Improvesensor configurationVSAvoideffort feedback completeness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the position sensor information is fed into a control law that also incorporates acceleration data. The system uses this feedback to calculate and apply the appropriate combination of stiffness, damping, and inertia efforts. This feedback approach allows complete effort feedback to be achieved with minimal sensors, as the system continuously adjusts the motor output based on the calculated requirements from position and acceleration measurements.

Inventive Principle:

Principle #23Feedback

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

Enables the user to feel inertia, stiffness, and damping efforts, improving stability margins and reducing the complexity and cost of the control device by eliminating the need for additional sensors.

Implementation Method 1

a motor (MO) comprising a shaft (out) and a stator, the shaft being rotatably mounted in the stator

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20240025534A1Method for controlling an aircraft control engine, control device and aircraft

Publication Date: 2024.01.25 SAFRAN ELECTRONICS & DEFENSE (FR)

AI summary

A method for controlling an engine, a device for controlling an engine and an aircraft, the method comprising the steps of determining a first intensity Kp, representing a stiffness, according to a physical stiffness Kss of the mechanical connection and a stiffness setpoint Kpspec to be rendered on the control column, a second intensity Kv, representing a damping, according to a physical damping fss between the control column and the engine and a damping setpoint Kvspec to be rendered on the control column, and a third intensity Ka, representing an inertia, according to a physical inertia Jss of the control column and an inertia setpoint Kaspec to be rendered on the control column.