Robotic Mower Travelling Containment Zones for Even Lawn Coverage

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Solution Overview

Problem

Robotic lawn mowers often inefficiently cover lawns due to random travel patterns and varying property boundaries, leading to uneven cutting and potential hang-ups in narrow areas, which can extend mowing times and result in missed areas.

Innovation Solution

Implementing a method where the mower operates within a dynamically changing 'travelling containment zone' defined by virtual boundaries, allowing for even coverage and efficient navigation across the lawn by adjusting speed and movement based on cutting load and obstacles, ensuring all areas are adequately covered.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the mower uses a random travel pattern within a fixed property boundary, then the mower can operate autonomously without complex path planning, but the coverage becomes uneven and some areas may be missed or repeatedly mowed

Engineering Contradiction:
Improveautonomous operation simplicityVSAvoidcoverage uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent transforms the static fixed boundary into a dynamic travelling containment zone that moves across the work region over time. The virtual boundary is continuously updated to encompass only the uncut portion of the lawn, allowing the mower to systematically cover the entire area while maintaining autonomous operation. This dynamic adjustment ensures uniform coverage without requiring complex pre-planned paths.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the mower operates in a fixed boundary zone, then the containment area is simple to define, but the mower may get hung-up in narrow areas and mow the same areas repeatedly

Engineering Contradiction:
Improveboundary definition simplicityVSAvoidmowing efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The travelling containment zone dynamically shrinks and relocates as the mower progresses through the work region. Instead of a fixed boundary, the virtual boundary continuously updates to reflect the remaining uncut area, preventing the mower from repeatedly entering already-mowed zones or becoming trapped in narrow passages. This increases productivity while maintaining simple boundary management.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the mower's position and cutting progress to continuously update the travelling containment zone. The virtual boundary is adjusted based on real-time information about which areas have been mowed, ensuring the mower always operates in uncut regions and optimizing the mowing path without complex pre-planning.

Inventive Principle:
Principle #23Feedback

3Device complexity

If the mower covers the entire work region in one pass, then the boundary definition is simple, but the mower may require recharging before completing the task

Engineering Contradiction:
Improveboundary management simplicityVSAvoidmowing task completion time
Core Design Contradiction:
Device complexityVSDuration of action of moving object

Solution Approach 1:

The patent segments the mowing task into multiple phases, each corresponding to a travelling containment zone. The work region is divided into sequential zones that the mower completes one at a time. When the battery needs recharging, the mower can return to the base station and resume from where it left off, rather than requiring completion of the entire large area in one continuous operation. This segmentation allows longer overall task duration without increasing boundary management complexity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3821691B1Method for operating an autonomous robotic working machine within a travelling containment zone
Publication Date: 2022.01.12 THE TORO COMPANY
  • EP3821691B1 patent drawingFigure 1A
  • EP3821691B1 patent drawingFigure 1B
  • EP3821691B1 patent drawingFigure 2

AI summary

Apparatus, systems, and methods for directing an autonomous robotic vehicle such as a lawn mower relative to a work region. In some embodiments, the vehicle travels in a random pattern within a travelling containment zone of a lesser size than the work region. The travelling containment zone may move or travel across the work region such that, over time, the travelling containment zone travels over most all of a working surface of the work region.