Robotic Garden Tool Boundary Detection via Periodic Magnetic Signals

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Solution Overview

Problem

Robotic garden tools face challenges in detecting and maintaining awareness of their working area boundaries, leading to potential over-cutting or damage to non-target areas, due to high power requirements and sensitivity issues with existing boundary detection systems, especially in environments with ferromagnetic materials.

Innovation Solution

A system comprising a sensing means and control unit that wirelessly detects status and boundary signals, allowing the robotic garden tool to operate without continuous boundary detection, using sensors to differentiate between working and non-working areas, and generating commands to prevent boundary breaches, with reduced sensitivity and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous boundary signal detection is implemented, then boundary detection reliability is improved, but power consumption increases and system complexity increases

Engineering Contradiction:
Improveboundary detection reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic boundary signal transmission where the boundary wire transmits magnetic field signals at intervals rather than continuously. The robotic garden tool periodically detects these signals to determine boundary location and generate warning signals, reducing overall power consumption while maintaining adequate boundary detection reliability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses the robotic garden tool's existing operational movements and sensing capabilities to perform boundary detection as part of its normal operation, rather than requiring dedicated continuous detection mechanisms. The tool leverages its own motion through the workspace to naturally encounter and detect boundary signals.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If high power generator is used for boundary signal, then signal detection range is improved, but power consumption increases and system complexity increases

Engineering Contradiction:
Improvesignal detection capabilityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent introduces a warning signal generation mechanism that acts as an intermediary between boundary detection and tool operation control. When the robotic garden tool approaches the boundary or detects boundary signals, it generates warning signals to alert the operator, providing intermediate feedback without requiring high-power continuous detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the detection parameters by using periodic sampling of boundary signals rather than continuous high-sensitivity detection. This allows the use of lower power generators while maintaining adequate detection capability through optimized detection timing and sensitivity settings.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If ferromagnetic materials are present in workspace, then operational versatility is improved, but boundary signal detection accuracy deteriorates due to magnetic field attenuation

Engineering Contradiction:
Improveworkspace compatibilityVSAvoidboundary signal detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where the robotic garden tool continuously monitors boundary signal strength and generates warning signals when signal quality deteriorates or when approaching boundary areas with potential ferromagnetic interference. This allows the system to adapt its operation based on real-time detection conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts its detection and warning behavior based on the detected magnetic field conditions. When ferromagnetic materials are detected or boundary signals are attenuated, the warning signal generation parameters are adjusted to maintain operational awareness despite the challenging magnetic environment.

Inventive Principle:
Principle #15Dynamics

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

Enables secure and efficient operation within defined areas, reducing the risk of boundary breaches and maintaining effective boundary detection with lower power requirements and improved sensitivity, even in challenging environments.

Implementation Method 1

a boundary wire adapted to send a boundary signal, wherein the boundary signal comprises a magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP2590495B1Communication and safety device for boundary aided systems
Publication Date: 2020.04.15 HUSQVARNA AB
  • EP2590495B1 patent drawingFigure 1
  • EP2590495B1 patent drawingFigure 2A~2B
  • EP2590495B1 patent drawingFigure 3

AI summary

The present invention relates to a method 400 and a system 100 for controlling a robotic garden tool 202 around a working area 204 in a boundary wire aided system. The system includes the robotic garden tool 202 to perform an operation within the working area 204, which is at least partly defined by a boundary. The boundary separates the working area 204 from a non-working area. The robotic garden tool also includes detecting means for detecting the boundary. Further, the robotic garden tool 202 is adapted to receive a status signal 110 sent from a signal source and the robotic garden tool 202 is configured to stop the operation, when the status signal 110 provides a stopping signal.