eVTOL Flight Control Fail-Safe Mode Switching for Safe Landing

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Solution Overview

Problem

Existing flight control systems for vertical take-off and landing aircraft do not adequately address the safety concerns when abnormalities occur, potentially leading to inappropriate emergency evacuation operations.

Innovation Solution

A flight control device that includes a normality setting unit for normal modes and a fail-safe unit to change to fail-safe modes for safe landing when abnormalities occur, allowing selection of a suitable operating mode for safe landing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed emergency evacuation operation is performed when an abnormality occurs, then the response is simple and quick, but the operation may not be appropriate for the current flight state, reducing safety

Engineering Contradiction:
ImprovesafetyVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system dynamically switches between normal mode and fail-safe modes based on the detected abnormality state. The fail-safe mode itself is dynamic, selecting different landing procedures (immediate landing, return-to-base landing, or hover) based on the current flight state such as altitude, speed, and battery level, making the system adaptive rather than fixed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters by switching between different modes. When an abnormality is detected, the system transitions from normal operation parameters to fail-safe parameters, including different thrust allocations, landing procedures, and flight path adjustments based on the specific abnormality and current flight state

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the operating mode is changed based on the normal mode at the time of abnormality, then the appropriate fail-safe mode can be selected, but the control logic becomes more complex

Engineering Contradiction:
ImprovesafetyVSAvoidcontrol logic complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system is segmented into distinct normal modes (takeoff, hover, landing) and fail-safe modes corresponding to each. This segmentation allows the system to have pre-defined, simple transition rules from each normal mode to its corresponding fail-safe mode, reducing the complexity of real-time decision logic while ensuring appropriate safety responses

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4428040B1Flight control device, and control device for vertical takeoff/landing aircraft
Publication Date: 2025.10.01 DENSO CORP
  • EP4428040B1 patent drawingFigure 1
  • EP4428040B1 patent drawingFigure 2
  • EP4428040B1 patent drawingFigure 3

AI summary

A flight control device executes flight control processing for causing the eVTOL to fly. The flight control device sets an operating mode to one of fail-safe modes based on current one of normal modes when an abnormality has occurred in an eVTOL. When the operating mode at the time of occurrence of the abnormality is a vertical landing mode, the flight control device changes the operating mode to a landing continuation mode in step S105. When the operating mode at the time of occurrence of the abnormality is a vertical take-off mode, the flight control device sets the operating mode to an emergency landing mode in step S107. When the operating mode at the time of occurrence of the abnormality is a cruise mode or a hovering mode, the flight control device sets the operating mode to a resetting mode in step S108.