Aircraft Brake Actuator Pressure Sensing With Virtual Sensor Redundancy

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Solution Overview

Problem

Existing aircraft braking systems are vulnerable to hydraulic leaks that can render both brakes inoperative simultaneously, and pressure sensor failures can lead to system inoperability, necessitating a solution for improved fault tolerance and redundancy.

Innovation Solution

An actuator equipped with dual pressure sensors and a virtual pressure sensor, where the monitoring controller and control controller are segregated, with the virtual sensor using a pressure model based on pump operating parameters to detect failures and switch to a degraded operating mode, ensuring continued functionality even with sensor or pump malfunctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single hydraulic power source is used for both brakes, then the system is simplified, but a hydraulic leak can render both brakes inoperative simultaneously

Engineering Contradiction:
Improvehydraulic system structureVSAvoidbrake system reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The hydraulic system is segmented into two independent circuits: a primary circuit with a pump and reservoir, and a secondary circuit with an accumulator. Each brake can be supplied by either circuit, providing redundancy. If one circuit fails due to a leak, the other circuit can still supply hydraulic power to both brakes, preventing total system failure.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a single pressure sensor is used for control, then the system is simpler, but sensor failure renders the system inoperative

Engineering Contradiction:
Improvesensor system structureVSAvoidactuator operation reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

Different sensors are placed in different locations within the hydraulic system: a first pressure sensor in the primary circuit and a second pressure sensor in the secondary circuit. Each sensor monitors its local circuit independently. This localized monitoring allows the system to detect failures in one circuit without affecting the operation of the other circuit or the entire system.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If pressure sensor failure is not detected, then the system continues operating, but undetected failures can lead to unsafe conditions

Engineering Contradiction:
Improvesystem continuous operationVSAvoidundetected sensor failure
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system implements feedback through a monitoring controller that continuously compares readings from both pressure sensors with expected values. When a discrepancy is detected indicating sensor failure, the monitoring controller generates an alert and can switch to using data from the functioning sensor, maintaining safe operation while notifying operators of the degradation.

Inventive Principle:
Principle #23Feedback

4Reliability

If redundant sensors are added for fault detection, then reliability improves, but device complexity increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoidsensor and controller structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The monitoring controller performs multiple functions: it monitors both pressure sensors, compares readings against expected values, detects sensor failures, generates alerts, and can switch between sensors. This multi-functional approach consolidates what could be separate systems into a single controller, reducing overall system complexity while maintaining high reliability through redundant sensing.

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

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

The actuator provides enhanced fault tolerance by detecting and responding to sensor or pump failures, maintaining system operation and preventing total loss, even in the event of hydraulic leaks or sensor failures.

Implementation Method 1

a first pressure sensor, the first pressure sensor being arranged on the second hydraulic connection and measuring a first supply pressure

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 2

a second pressure sensor, the second pressure sensor being arranged on the second hydraulic connection and measuring a second supply pressure

Methodology Applied
Scientific EffectPressure measurement:

Implementation Method 3

a pump connected to a first hydraulic connection and a second hydraulic connection, the first hydraulic connection being connected to a reservoir containing a fluid

Methodology Applied
Scientific EffectHydraulic pressure generation: Hydraulic Press

Data Source

PatentEP4556325B1Actuator provided with two pressure sensors and a virtual pressure sensor; a braking system and an aircraft provided with such an actuator, and the applied method
Publication Date: 2025.11.12 EUROCOPTER FRANCE SA
  • EP4556325B1 patent drawingFigure 1~2
  • EP4556325B1 patent drawingFigure 3

AI summary

The present invention relates to an actuator (10) provided with a pump (15) connected to a first hydraulic connection (30) connected to a reservoir (25) and to a second hydraulic connection (35). A control controller (40) communicates with a first pressure sensor (41) arranged on the second hydraulic connection (35) and measuring a first supply pressure. A monitoring controller (50) communicates with the control controller (40) and a second pressure sensor (51) arranged on the second hydraulic connection (35) and measuring a second supply pressure. A virtual pressure sensor is provided with a verification instrument (55) transmitting at least one verification signal (SVERIF) carrying an operating parameter of the pump (15) to the control controller (40) and to the monitoring controller (50) to identify a failure of the actuator (10) and consequently apply a degraded operating mode.