UAV Motor Stop Relay Diagnosis for Emergency Rotor Shutdown

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Solution Overview

Problem

Unmanned aerial vehicles (UAVs) require improved fault diagnosis systems for relay circuits to ensure safe emergency stopping of rotor rotation.

Innovation Solution

A termination system comprising a relay circuit and a diagnostic device that interrupts control signals to motor drive circuits, allowing for emergency stoppage of rotor rotation, and a controller that changes the operation from a flight state to a non-flight state upon receiving a stop signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If relay circuits are used for emergency stopping of rotor rotation, then safety is improved, but fault diagnosis capability deteriorates

Engineering Contradiction:
ImprovesafetyVSAvoidfault diagnosis capability
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements feedback by having the controller monitor the output signals of the relay circuit and detect whether they are in a normal high-level state or an abnormal low-level state. This feedback mechanism enables automatic fault diagnosis of the emergency stop function without additional hardware, resolving the contradiction between safety and diagnosability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-diagnosis where the controller uses its existing processing capabilities to monitor relay circuit status. The controller automatically detects relay failures by checking output signal levels and manages fault information, eliminating the need for separate diagnosis systems while maintaining safety functionality.

Inventive Principle:
Principle #25Self-service

2Reliability

If relay circuits are used for emergency stopping, then emergency stop function is improved, but system complexity increases

Engineering Contradiction:
Improveemergency stop functionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The controller serves multiple functions: it controls motor drive circuits during normal operation and simultaneously monitors relay circuit output signals for fault diagnosis. This multi-functionality eliminates the need for separate diagnosis hardware, maintaining emergency stop capability while reducing overall system complexity.

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

Solution Approach 2:

The patent merges the emergency stop function and fault diagnosis function into a single integrated system. The relay circuit remains separate for safety, but the diagnosis capability is combined with the existing controller, reducing total system complexity compared to having separate dedicated diagnosis hardware.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4620836A1Unmanned aerial vehicle and stop system
Publication Date: 2025.09.24 KUBOTA CORP
  • EP4620836A1 patent drawingFigure 1A
  • EP4620836A1 patent drawingFigure 1B
  • EP4620836A1 patent drawingFigure 1C

AI summary

An unmanned aerial vehicle includes: a plurality of electric motors, each configured to rotate a respective one of a plurality of rotors; a plurality of motor drive circuits, each configured to drive a respective one of the plurality of electric motors; and a controller configured to control operation of the plurality of motor drive circuits. The controller is configured to change the operation of the plurality of motor drive circuits from a flight state of the unmanned aerial vehicle to a state where flight is not possible in response to a stop signal.