Robotic Garden Tool Navigation Using Low-Accuracy GPS and Boundary Signals

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Solution Overview

Problem

Current robotic garden tools face inefficiencies due to complex integration and high costs associated with GPS navigation systems, which can lead to repeated mowing of areas and loss of boundary awareness if GPS contact is lost.

Innovation Solution

A system that uses a low-accuracy positioning device, such as a standard GPS, in conjunction with a sensor unit to detect boundary signals, allowing the control unit to generate a map and commands for efficient navigation within a lawn area, dividing it into subareas and determining the robotic garden tool's location for optimized operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If GPS navigation system is used to provide accurate location data, then navigation accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvelocation accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines a low-accuracy positioning device with boundary wire signals to achieve accurate location determination. The control unit merges GPS coordinates with boundary signal data to calculate precise position, eliminating the need for expensive high-accuracy GPS systems while maintaining navigation accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces boundary wires as an intermediary element that provides reference signals for position calculation. These wires act as a mediator between the low-accuracy GPS and the navigation system, enabling precise location determination through signal processing without requiring expensive GPS hardware.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If GPS navigation system is used to track mowed areas, then navigation accuracy is improved, but cost increases

Engineering Contradiction:
Improvearea tracking accuracyVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The system merges inexpensive low-accuracy GPS with boundary wire signal detection to achieve accurate area tracking. The control unit combines coordinate data from the positioning device with boundary signal information to determine which areas have been mowed, eliminating the need for expensive dedicated tracking systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a standard low-accuracy GPS device instead of expensive high-accuracy positioning systems. By combining this inexpensive positioning device with boundary wire signals, the system achieves accurate area tracking at minimal cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If only boundary wire signals are used for navigation, then device complexity is reduced, but location-based information is lost

Engineering Contradiction:
Improvesystem complexityVSAvoidlocation information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent segments the navigation information into two parts: boundary definition from wire signals and position coordinates from GPS. The control unit processes these segmented information sources separately and combines them to provide complete location-based navigation data.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The boundary wire signals serve as an intermediary that provides reference framework information, while the GPS provides absolute position data. Together they enable the system to maintain location awareness without requiring complex high-accuracy positioning hardware.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If low-accuracy GPS is used instead of high-accuracy GPS, then cost is reduced, but position precision deteriorates

Engineering Contradiction:
Improvesystem costVSAvoidposition accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent merges low-accuracy GPS coordinates with boundary wire signal data to achieve precise position determination. The control unit combines these two imperfect data sources to calculate accurate position information, making the system as accurate as expensive high-precision GPS while costing much less.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system changes the approach from relying on single high-precision GPS parameters to combining multiple lower-precision parameters (GPS coordinates plus boundary signal strength/distance) to achieve the desired position accuracy through parameter integration and processing.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3366100B1Robotic garden tool
Publication Date: 2020.04.08 HUSQVARNA AB
  • EP3366100B1 patent drawingFigure 1
  • EP3366100B1 patent drawingFigure 2
  • EP3366100B1 patent drawingFigure 3

AI summary

The present invention relates to a method (300) and a system (100) for navigating a robotic garden tool (202) based on one or more operating parameters for subareas (210-218) within the working area (204) and a current location of the robotic garden tool (202). The working area (204) is provided with a signal source (104) corresponding to which a sensor unit (106) is provided in the robotic garden tool (202) for detecting the one or more signals (102) from the signal source (104). The robotic garden tool (202) may include a low-accuracy positioning device (110) for providing co-ordinates of various subareas (210-218) and at any given instant, an approximate location of the robotic garden tool (202). The robotic garden tool (202) further includes a processor means (114) for comparing the coordinates of the subareas (210-218) and the approximate position of the robotic garden tool (202) to determine a current location of the robotic garden tool (202) in the working area (204).