Collective And Cyclic Stick Detent Monitoring for Sensor Fault Detection

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Solution Overview

Problem

As rotorcraft become larger and more complex, the differences between flying rotorcraft and fixed-wing aircraft become more pronounced, requiring sophisticated flight control systems to manage tightly coupled flight parameters, and existing fly-by-wire systems must provide stable flight characteristics while allowing pilot override and maintaining intuitive control, but they face challenges in detecting defective sensors and ensuring accurate pilot control inputs.

Innovation Solution

A fly-by-wire system with flight control computers that include error monitors and detent sensors to determine when a pilot is controlling a particular control stick, allowing for different flight profiles and automated functions based on detent states, and providing tactile feedback through trim motors and sensors to ensure accurate positioning and override capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If detent sensors are used to detect pilot control inputs, then control accuracy is improved, but sensor failure risk increases

Engineering Contradiction:
Improvecontrol input detection accuracyVSAvoidsensor failure risk
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary validation of detent sensor readings by comparing them with trim motor position commands before trusting the sensor data for flight control decisions. This preliminary check prevents faulty sensor readings from causing incorrect control actions

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the relationship between detent sensor inputs and trim motor positions, using feedback loops to detect inconsistencies. When a mismatch is detected, the system can alert the pilot or switch to alternative control modes, preventing sensor failures from compromising flight safety

Inventive Principle:
Principle #23Feedback

2Ease of operation

If automated flight control functions are added, then pilot workload is reduced, but system complexity increases

Engineering Contradiction:
Improvepilot workloadVSAvoidflight control system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The flight control system is designed to perform multiple functions through integrated software modules that can operate in different modes (fully automated, assisted, or manual). This multi-functionality allows the system to adapt to various flight situations and pilot preferences without requiring separate hardware systems for each function

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

Solution Approach 2:

The automated flight control system is divided into separate functional modules (detent sensor processing, trim motor control, flight envelope protection, etc.) that can be independently developed, tested, and maintained. This segmentation reduces overall system complexity by making each component manageable and fault-isolatable

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If trim motors are used to provide tactile feedback, then control precision is improved, but mechanical complexity increases

Engineering Contradiction:
Improvecontrol positioning accuracyVSAvoidmechanical linkage complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical feedback linkages with electronically controlled trim motors that receive commands from the flight control computer. This substitution eliminates the need for sophisticated mechanical spring systems or hydraulic feedback mechanisms, reducing mechanical complexity while maintaining precise control positioning through electronic actuation

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

Data Source

PatentEP3620373B1Stuck in detent monitors for collective and cyclic sticks
Publication Date: 2024.01.03 TEXTRON INNOVATIONS INC
  • EP3620373B1 patent drawingFigure 1
  • EP3620373B1 patent drawingFigure 2
  • EP3620373B1 patent drawingFigure 3

AI summary

In an embodiment, a rotorcraft (101) includes a control element; a first control sensor connected to the control element, the first control sensor operable to generate position data indicating an actual position of the control element; and a flight control computer (FCC) (205) in signal communication with the first control sensor, the FCC (205) being operable to determine a suggested position for the control element, the FCC (205) including an error monitor (403, 405, 407), the error monitor (403, 405, 407) being operable to compare the suggested position of the control element with the actual position of the control element and determine whether the first control sensor is functional or defective, the FCC (205) being further operable to provide a first flight management function when the first control sensor is determined to be functional, and the FCC (205) being further operable to provide a second flight management function when the first control sensor is determined to be defective.