APU Speed Signal Isolation for Control and Health Monitoring

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Aircraft auxiliary power units face challenges in maintaining signal integrity for both control functions and health monitoring systems, as existing systems rely on a single speed sensor, making them vulnerable to signal corruption and requiring redundant sensors which are costly.

Innovation Solution

A speed sensor signal is branched and passed through operational amplifiers and a voltage follower to isolate potential corruption, ensuring that any downstream issues do not affect the electronic control box's upstream operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a single speed sensor is used for both control and health monitoring, then cost is reduced, but signal integrity and reliability are compromised due to vulnerability to corruption

Engineering Contradiction:

Improvenumber of sensorsVSAvoidsignal integrity

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The single speed sensor signal is segmented into two separate pathways: one for the electronic control box and another for the health monitoring system. This segmentation allows independent protection and processing of each signal stream, preventing corruption in one system from affecting the other while maintaining cost efficiency through sensor consolidation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An intermediary isolation component is introduced between the speed sensor and the two downstream systems. This intermediary prevents signal corruption from propagating between systems while allowing both systems to receive the necessary speed signal, thus maintaining reliability without requiring redundant sensors.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If redundant speed sensors are installed for control and health monitoring, then reliability is improved, but cost increases

Engineering Contradiction:

Improvesignal integrityVSAvoidnumber of sensors

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The single speed sensor is designed to serve multiple functions simultaneously - providing accurate speed signals to both the electronic control box for real-time control and the health monitoring system for diagnostic purposes. This multi-functionality eliminates the need for redundant sensors while maintaining system reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

An isolation component acts as an intermediary that enables one sensor to safely serve multiple systems by preventing corruption propagation. This intermediary allows the single sensor to universally support both control and monitoring functions without compromising reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If a branch line is added to communicate speed signal to health monitoring system, then monitoring capability is improved, but risk of signal corruption increases

Engineering Contradiction:

Improvemonitoring capabilityVSAvoidsignal corruption risk

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

An isolation component is placed in the branch line to the health monitoring system, acting as an intermediary that allows the branch connection while preventing corruption propagation. This enables enhanced monitoring capability without increasing the risk of signal corruption affecting the main control system.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The signal distribution is segmented into isolated pathways, with the branch line to the health monitoring system being electrically isolated from the main control line. This segmentation allows the branch to provide monitoring capability while the isolation prevents harmful factors from affecting other systems.

Inventive Principle:

Principle #1Segmentation

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 effectively prevents signal corruption from traveling back upstream, maintaining reliable control functions while allowing health monitoring systems to receive necessary data without the need for redundant sensors, thus reducing costs and ensuring system integrity.

Implementation Method 1

The branch passes through an electronic component that will isolate the speed signal as it passes beyond the component and to the downstream use, such that corruption at a downstream use will not pass back upstream to corrupt the signals used in the electronic control box.

Methodology Applied

Scientific EffectElectrical isolation: Electrical Resistance

Data Source

PatentUS20100225122A1Auxiliary power unit with dual use of speed signals

Publication Date: 2010.09.09 HAMILTON SUNDSTRAND CORP

AI summary

An auxiliary power unit has a speed sensor for sensing a speed of operation of the auxiliary power unit. The speed sensor sends a signal to an electronic control box. The electronic control box is operable to control the auxiliary power unit. A branch line is for communicating the speed signal to a health monitoring system. The branch passes through an electronic component that will isolate the speed signal as it passes beyond the component and to the downstream use, such that corruption at a downstream use will not pass back upstream to corrupt the signals used in the electronic control box.