Robotic Garden Tool Coverage Control via Temporary Working Areas

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Solution Overview

Problem

Robotic garden tools often get stuck in narrow passages between sub-areas, leading to excessive cutting in one sub-area and poor coverage of remote sub-areas due to random or semi-systematic movement patterns, and existing solutions fail to effectively keep the tool within remote sub-areas.

Innovation Solution

A system that includes steering control, positioning devices, target point selection, and temporary working area definition, allowing the robotic garden tool to be guided and kept within a selectively adapted temporary working area, using GNSS receivers and working area data to adjust movement directions and area sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the robotic garden tool moves in a random or semi-systematic pattern, then the tool can cover the working area, but the tool gets stuck in narrow passages between sub-areas leading to excessive cutting in one sub-area and poor coverage of remote sub-areas

Engineering Contradiction:
Improvecoverage distributionVSAvoidcoverage uniformity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The working area is divided into multiple sub-areas, and the tool sequentially processes each sub-area rather than moving randomly throughout the entire area. This segmentation prevents the tool from getting stuck in narrow passages by confining movement to larger sub-area boundaries, ensuring more uniform coverage distribution across all sub-areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system pre-calculates and determines an optimal starting position within a sub-area before the tool begins operation. By selecting a strategic starting point that considers the geometry of sub-areas and passage locations, the tool is positioned to minimize the risk of becoming trapped in narrow passages, thereby improving coverage reliability from the outset.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the robotic garden tool follows the boundary wire to a remote sub-area every time it leaves the charging station, then the mower starts in the right place, but the movement pattern remains random based and the tool may leave the remote sub-area almost immediately after arriving

Engineering Contradiction:
Improvestarting position accuracyVSAvoidcoverage efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system dynamically adjusts the tool's movement behavior based on its location and the coverage status of different sub-areas. Rather than following a fixed boundary-wire protocol, the tool adapts its path planning in real-time to maintain presence in remote sub-areas longer, improving coverage efficiency while maintaining accurate positioning through continuous boundary wire following when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms that monitor the tool's position, coverage progress, and sub-area visitation history. This feedback enables the control system to make intelligent decisions about when to follow boundary wires to remote sub-areas and when to prioritize other coverage tasks, preventing premature departure from remote sub-areas while maintaining starting position accuracy.

Inventive Principle:
Principle #23Feedback

3Productivity

If the robotic garden tool uses a systematic movement pattern, then coverage can be improved, but the tool complexity increases with additional control systems and sensors

Engineering Contradiction:
Improvecoverage distributionVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The boundary wire serving system is designed to perform multiple functions: it provides both the traditional boundary definition for area confinement and additionally serves as a navigation aid for reaching remote sub-areas. This multi-functionality enables systematic movement patterns without adding separate complex navigation systems, maintaining relatively simple device architecture while improving coverage distribution.

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

Data Source

PatentEP2906032B1System for enhancing a coverage distribution of a robotic garden tool
Publication Date: 2022.06.22 HUSQVARNA AB
  • EP2906032B1 patent drawingFigure 1
  • EP2906032B1 patent drawingFigure 2~3
  • EP2906032B1 patent drawingFigure 4~5

AI summary

A method for enhancing a coverage distribution of a robotic garden tool (100) operating within a predetermined working area (200), wherein the robotic garden tool (100) is provided with steering control means operable to change a movement direction of the robotic garden tool (100), and a positioning device (120). The method comprises the steps of providing (301) working area related data, defining (302) a temporary working area (500), based on the working area related data, which temporary working area (500) at least partly extends within the working area (200), estimating (303) a current position (600) of the robotic garden tool (100), evaluating (304) the estimated current position (600), selectively adapting (305) the temporary working area (500), in response to the step of evaluating (304) the estimated current position, selectively adapting (306) a movement direction of the robotic garden tool (100), in response to the step of evaluating (304) the estimated current position. The steps of selectively adapting (305) the extension of the temporary working area (500) and selectively adapting (306) a movement direction of the robotic garden tool are performed so as to push the robotic garden tool towards the temporary working area or so as to keep the robotic garden tool within the temporary working area (500).