Turbojet Thrust Reverser Actuator Fault Detection Circuit

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Solution Overview

Problem

The existing control systems for thrust reverser cowls in turbojet engines face challenges with pneumatic and hydraulic systems, which require significant maintenance due to potential leaks and are cumbersome to install, while electromechanical actuators can fail, leading to overheating and safety risks due to undetected component failures.

Innovation Solution

A control system for at least one cowl actuator of a thrust reverser using an electric motor with an electric circuit that includes measurement means to detect faults, fault isolation means to inhibit faulty components, and communication means to alert users, allowing for automatic isolation of failures and maintaining system operation without user intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If pneumatic or hydraulic systems are used to actuate movable cowls, then the actuators can provide sufficient force for deployment, but the systems require significant maintenance due to potential leaks and are cumbersome to install

Engineering Contradiction:
Improveactuator forceVSAvoidsystem complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent replaces pneumatic or hydraulic actuation systems with an electromechanical actuator that uses a motor and reduction gear to provide the necessary force for deploying and retracting the movable cowls. This substitution eliminates the need for complex fluid delivery networks, reducing maintenance requirements and installation complexity while maintaining sufficient actuator force.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a circuit breaker is integrated into the electric circuit to detect failures, then the control system can be made unavailable to prevent overheating, but the circuit breaker does not detect all types of component failures

Engineering Contradiction:
ImprovesafetyVSAvoidfailure detection capability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements a comprehensive monitoring system that continuously measures multiple electrical parameters (current, voltage, temperature) and provides feedback to the control unit. This feedback mechanism enables the detection of various failure modes beyond what a simple circuit breaker can detect, allowing for more reliable safety control while maintaining system availability when appropriate.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control unit serves multiple functions: it controls the motor operation, monitors electrical parameters, detects various types of failures, and manages the unblocking mechanism. This multi-functional approach replaces the limited circuit breaker with a comprehensive control system that can detect all types of component failures and respond appropriately.

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

3Object-affected harmful factors

If the control system is made unavailable upon detecting a component failure, then overheating and explosions can be prevented, but the entire system must be shut down even when only one component fails

Engineering Contradiction:
Improveoverheating preventionVSAvoidsystem availability
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent divides the control system into independent functional modules (motor control, parameter monitoring, failure detection, unblocking mechanism). When a failure is detected in one module, only that specific module is isolated or placed in a safe state, while other modules can continue to operate. This segmentation allows the system to maintain partial functionality and availability even when individual components fail.

Inventive Principle:
Principle #1Segmentation

4Weight of moving object

If electromechanical actuators are used to replace pneumatic or hydraulic systems, then weight and bulk are reduced, but the actuators require a complete control system with multiple components that can present failures

Engineering Contradiction:
Improveactuator weightVSAvoidcontrol system complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent merges the control functions (motor control, parameter monitoring, failure detection) and the unblocking mechanism into an integrated control unit. This consolidation reduces the overall number of separate components and interconnections required, thereby reducing weight and complexity compared to having separate systems for each function, while still providing comprehensive control and safety capabilities.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2181373B1System for controlling at least one actuator for the cowlings of a turbojet engine thrust reverser
Publication Date: 2015.05.20 AIRCELLE SA
  • EP2181373B1 patent drawingFigure 1~2
  • EP2181373B1 patent drawingFigure 3

AI summary

The control system of the invention includes at least one actuator (6) for a cowling (2), driven by at least one electric motor (7), and control means (9) for the electric motor (7) and the actuator (6). The control system includes an electric circuit (C) that comprises: a plurality of electric components; a plurality of measuring means (16-18) adapted for measuring respectively a magnitude characteristic of an electric component or a group of electric components in the electric circuit; a failure detection means (19) adapted for detecting a failure at a component of the electric circuit when the characteristic magnitude measured at said component exceeds a predetermined value or belongs to a range of predetermined values.