Robotic Mower Boundary Coverage System

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Solution Overview

Problem

Robotic lawn mowers often damage turf near perimeter wires due to repetitive path following, causing wear and ruts from constant wheel contact in the same areas.

Innovation Solution

A robotic mower boundary coverage system that includes a vehicle control unit commanding a traction drive system to adjust yaw angles and distances relative to a boundary wire, using boundary sensors to alternate paths toward and away from the wire, thereby minimizing turf damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the robotic mower follows a path along or adjacent to the boundary wire, then the mower can effectively cover the boundary area, but the turf near the perimeter wire suffers damage due to repetitive wheel contact

Engineering Contradiction:
Improveboundary area coverageVSAvoidturf damage and wear
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically adjusts the mower's path by alternating between following the boundary wire and offsetting at a predetermined distance. The controller receives boundary wire location data and dynamically generates varying paths that prevent repetitive wheel contact with the same turf areas while maintaining boundary coverage effectiveness.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mower implements periodic alternation between boundary-following mode and offset mode. After a certain period or distance along the boundary, the system automatically switches to offsetting at the predetermined distance, then alternates back, creating a periodic pattern that distributes wear across different turf areas while ensuring periodic boundary coverage.

Inventive Principle:
Principle #19Periodic action

2Reliability

If the robotic mower repeatedly follows the same path along the boundary, then consistent boundary coverage is achieved, but ruts and wear occur due to constant wheel contact in the same areas

Engineering Contradiction:
Improveboundary coverage consistencyVSAvoidruts and turf wear
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The system dynamically varies the operational path by switching between two distinct modes: boundary-following mode for consistent coverage and offset mode at predetermined distance to distribute mechanical stress. This dynamic path variation maintains coverage reliability while eliminating repetitive wear patterns that cause ruts.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system applies different path-following strategies to different sections of the boundary. By alternating between direct boundary following and offsetting at predetermined distances, the mower creates local variations in the path that prevent concentrated wear in specific areas while maintaining overall boundary coverage quality.

Inventive Principle:
Principle #3Local quality

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

The system effectively reduces turf damage by varying the robotic mower's path along the boundary, preventing repetitive wear and ruts, and ensuring more efficient area coverage.

Implementation Method 1

a boundary sensor on the robotic mower signaling the distance between the boundary wire and the vehicle control unit

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2413214B1Robotic mower boundary coverage system and robotic mower
Publication Date: 2013.09.11 DEERE & CO
  • EP2413214B1 patent drawingFigure 1
  • EP2413214B1 patent drawingFigure 2
  • EP2413214B1 patent drawingFigure 3

AI summary

A robotic mower boundary coverage system includes a vehicle control unit (101) on the robotic mower (100) commanding a traction drive system to drive the robotic mower (100) at a specified yaw angle with respect to a boundary wire (103, 104); a boundary sensor (119) on the robotic mower (100) signaling the distance between the boundary wire (103) and the vehicle control unit (101); the vehicle control unit (101) alternating commands to direct the traction drive system toward and away from the boundary wire (103, 104) based on the distance of the robotic mower (100) to the boundary wire (103, 104).