Helicopter Flight Actuator Safe Control Device

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing control devices for helicopter flight actuators are prone to transient periods of incorrect command during calculation chain failures, which can be dangerous in reactive and unstable aircraft, as the pilot's reaction time may not suffice to compensate for the effects of high-amplitude incorrect commands.

Innovation Solution

A safe control device that generates and compares direction and speed instructions independently from two calculation chains after temporal synchronization, eliminating the transient period by using a circuit for mixing instructions and a power stage with an H bridge architecture, thereby reducing the impact of sudden failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a control device uses a single calculation chain for actuator commands, then the device complexity is reduced, but the reliability deteriorates due to transient periods of incorrect command during failures

Engineering Contradiction:

Improvecontrol device architectureVSAvoidcommand accuracy during failure

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The control device is divided into two independent calculation chains (first and second chains) that each independently generate actuator commands. This segmentation allows the system to compare commands from both chains and detect failures, thereby improving reliability without excessive complexity increase.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control device implements a feedback mechanism where the command from the first calculation chain is compared with the command from the second calculation chain. This comparison provides feedback that enables detection of transient periods or failures, allowing the system to switch to the reliable chain and maintain command accuracy.

Inventive Principle:

Principle #23Feedback

2Device complexity

If the pilot's reaction time is used to compensate for incorrect commands, then no additional control system is needed, but the safety deteriorates in reactive and unstable aircraft

Engineering Contradiction:

Improvecontrol system structureVSAvoidpilot-induced hazards

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The control device performs preliminary action by detecting transient periods or failures in the command generation before they can affect the actuator. By comparing commands from two independent calculation chains in advance, the system can switch to the reliable chain and prevent incorrect commands from being executed, thereby eliminating the need for pilot compensation.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a redundant calculation chain is added for safety, then the reliability is improved, but the device complexity increases

Engineering Contradiction:

Improvecommand accuracy during failureVSAvoidcontrol device architecture

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The control device introduces an intermediary comparison mechanism that evaluates commands from both calculation chains before actuator execution. This intermediary layer enables failure detection and chain switching without requiring complete architectural redesign, balancing reliability improvement with acceptable complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS7711456B2Device for safely operating a flight control actuator of an aircraft

Publication Date: 2010.05.04 THALES SA

AI summary

The field of the invention is that of safe devices for operating the actuators of aircraft and more specifically the flight control actuators of a helicopter. The invention consists of a safe control device for commanding an actuator (15) movement comprising at least two independent calculation chains (120), (130), a circuit for mixing instructions (65) and a power stage (88), each calculation stage delivering a direction of movement instruction and a speed of movement instruction for the actuator, the instructions being transmitted to the circuit for mixing instructions (65) in order to generate a primary movement command for the actuator comprising modulated pulse trains, the power stage receiving the primary movement command and delivering a power movement command to the actuator (15). According to the invention, the circuit for mixing instructions (65) compares the direction of movement instructions and the speed of movement instructions in pairs in order to generate the primary movement command for the actuator.