Actuator Control with Redundant Sensor Fault Isolation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing actuator control systems with redundant sensors fail to accurately detect and compensate for faulty position sensors, leading to erroneous control signals, increased wear, and costly maintenance due to lack of diagnostic capabilities.

Innovation Solution

A method and control device that calculate deviations between position measurement signals, set the control signal to a constant value when deviations exceed a threshold, and define position intervals to detect faulty sensors, allowing for automatic detection and exclusion of faulty signals without human intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the control system continues to operate in closed loop using a faulty sensor signal, then the actuator position is continuously regulated, but the regulation is based on erroneous and noisy feedback causing rapid position variations and increased wear

Engineering Contradiction:

Improveactuator position regulationVSAvoidactuator wear and oscillations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary detection of sensor faults by monitoring signal consistency between redundant sensors before fault occurs. When a deviation exceeds the threshold, the system preemptively switches to open-loop control and immobilizes the actuator, preventing the harmful oscillations and wear that would result from continued closed-loop operation with faulty feedback.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If the system selects the extreme value (maximum or minimum) as a safety signal when deviation exceeds threshold, then certain edge effects are minimized, but the faulty sensor cannot be identified and the erroneous signal continues to drive regulation

Engineering Contradiction:

Improveedge effectsVSAvoidsensor fault detection

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The system uses feedback from redundant sensors to monitor each other's signals. By comparing the two sensor readings and detecting deviations beyond a threshold, the system identifies which sensor has failed. This feedback mechanism allows precise fault detection while maintaining safety through open-loop control during the fault condition.

Inventive Principle:

Principle #23Feedback

3Device complexity

If no diagnostic of the failure is carried out, then the system structure remains simple, but maintenance teams must be called to perform manual diagnostics which is time-consuming and costly

Engineering Contradiction:

Improvecontrol system structureVSAvoidmaintenance time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The control system performs self-diagnosis by automatically detecting sensor failures through comparison of redundant sensor signals. When a fault is detected, the system autonomously switches to open-loop control and immobilizes the actuator, eliminating the need for manual diagnostic intervention and reducing maintenance time and costs while maintaining acceptable system complexity.

Inventive Principle:

Principle #25Self-service

4Productivity

If the actuator remains in closed loop control with a faulty sensor, then the system responds dynamically to set-point changes, but the fuel consumption increases unduly and engine performance degrades

Engineering Contradiction:

Improveengine responseVSAvoidfuel consumption

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The system preemptively detects sensor faults and switches to open-loop control before significant performance degradation occurs. By immobilizing the actuator and preventing erroneous closed-loop regulation, the system avoids the excessive fuel consumption and performance loss that would result from continued operation with faulty feedback, while maintaining the capability to respond dynamically once the fault is resolved.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11320801B2Method for controlling an actuator and associated control by changing to open loop control when redundant sensors are not in agreement

Publication Date: 2022.05.03 SAFRAN AIRCRAFT ENGINES SAS

AI summary

The present invention relates to a method for controlling an actuator (4) comprising a mobile element (60), the method comprising steps of receiving a set-point signal and two position-measurement signals (A, B) of the mobile element (60) acquired by different position sensors (7), calculating a deviation between the two position-measurement signals (A, B), generating (102) a control signal (S) for controlling a movement of the mobile element (60) on the basis of the set-point signal (E) and at least one of the position-measurement signals (A, B), the method being characterised in that when the deviation between the position-measurement signals (A, B) crosses (201) a predetermined threshold, said method comprises the following steps: setting (202) the control signal (S) to a constant value so as to immobilise the mobile element (60), for each of the two measurement signals (A, B), calculating an interval of positions associated with the measurement signal (A), and detecting an output of the value of a measurement signal (A) outside the associated interval while the control signal (S) is set to the constant value.