UAV Winch Spool Tension Control for Wire Management

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Solution Overview

Problem

Unmanned aerial vehicles (UAVs) face challenges in controlling the winch when lifting or lowering cargo, as the wire can become loose and entangled after unloading, and the hook may not be wound back properly due to insufficient driving force, leading to obstacles during return flights.

Innovation Solution

Incorporating a sensor to detect wire tension and a controller that restricts spool rotation based on threshold values, ensuring the wire is not unwound excessively after cargo release and allowing the hook to be lifted to a safe position by setting specific threshold values for forward and backward spool rotations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the winch is controlled automatically by program only, then the operation is simple, but the wire becomes loose and entangled after cargo release

Engineering Contradiction:
Improvewinch control operationVSAvoidwire control reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies feedback control by using a sensor to detect wire tension and feeding this information back to the controller. The controller adjusts spool rotation based on the detected tension, preventing wire loosening and entanglement while maintaining simple operation. This resolves the contradiction by enabling reliable wire control through automatic feedback mechanisms without complicating the operator's interface.

Inventive Principle:
Principle #23Feedback

2Reliability

If sufficient driving force is applied to the spool, then the wire can be wound up properly, but the mechanism becomes complex and energy consumption increases

Engineering Contradiction:
Improvewire winding reliabilityVSAvoidwinch mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic control of the spool driving force based on real-time wire tension detection. The controller adjusts the motor output dynamically according to the detected tension levels, providing sufficient force only when needed for winding while reducing force during other phases. This maintains reliable wire winding without requiring an overly complex or high-power mechanism throughout the entire operation cycle.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the spool rotates backward freely for unwinding, then cargo delivery is efficient, but the wire becomes loose and entangled after unloading

Engineering Contradiction:
Improvecargo delivery efficiencyVSAvoidwire tension control
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by detecting when cargo is released (when tension drops below threshold S1) and immediately restricting backward spool rotation to prevent wire loosening and entanglement. This preliminary protective action occurs right after cargo delivery, maintaining delivery efficiency while preventing the subsequent problem of wire entanglement during the return flight phase.

Inventive Principle:
Principle #9Preliminary anti-action

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

This solution enables smooth lifting and lowering of cargo, prevents wire loosening during unloading, and ensures the hook can be retrieved without getting caught in obstacles, improving operational safety and efficiency.

Implementation Method 1

a sensor (14) for detecting the tension of the wire (20)

Methodology Applied
Scientific EffectTension detection: Force

Implementation Method 2

a motor (12b) for rotating the spool (15b)

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

a winch (15) for rotatably supporting a spool (15b) on which the wire (20) is wound in the forward and backward directions, winding the wire by rotating the spool in the forward direction

Methodology Applied
Scientific EffectMechanical rotation: Wheel and Axle

Data Source

PatentEP3674213B1Unnmanned aerial vehicle for the transport of a payload
Publication Date: 2024.12.04 DAIWA SEIKO CORPORATION
  • EP3674213B1 patent drawingFigure 1~2
  • EP3674213B1 patent drawingFigure 3a
  • EP3674213B1 patent drawingFigure 3b

AI summary

This unmanned aerial vehicle according to an embodiment of the present invention has: a main body; a plurality of rotary wings provided on the main body; a wire for suspending an object from the main body; a hook attached to the wire; a winch for rotatably supporting a spool on which the wire is wound in the forward and backward directions, winding the wire by rotating the spool in the forward direction and unwinding the wire by rotating the spool in the backward direction; and a controller for restricting the backward rotation of the spool when the tension of the wire becomes less than a first threshold value, and restricting the forward rotation of the spool when the tension of the wire becomes less than the first threshold value and becomes equal to or less than a second threshold value, which is less than a gravitational force acting on the hook.