Autonomous Lawn Mower Navigation and Docking on Uneven Terrain

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Solution Overview

Problem

Existing autonomous lawn mowers struggle with navigating diverse and complex landscapes, leading to inadequate performance and user preference for manual control due to the unpredictability of garden terrain and high manufacturing costs.

Innovation Solution

An autonomous lawn mower equipped with a navigation system comprising odometry, inertial measurement units, optical surveying, sonic obstacle detection, and other sensors, along with a controller that processes data to generate commands for precise movement and operation within predefined areas, including a detachable docking module for battery charging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If autonomous lawn mowers are equipped with navigation systems and sensors to improve autonomous operation capability, then the extent of automation and navigation precision are improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveautonomous operation capabilityVSAvoidsystem complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The navigation system is divided into separate functional modules: odometry module for position tracking, inertial measurement unit for orientation detection, optical surveying module for boundary recognition, and sonic obstacle detection module for collision avoidance. Each module operates independently but contributes to the overall autonomous navigation capability, making the complex system manageable and maintainable

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The controller integrates multiple functions into a single processing unit that handles data from all sensors, generates navigation commands, controls motor operations, and manages battery charging cycles. This multi-functional approach reduces the number of separate components needed while maintaining comprehensive autonomous operation capability

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

2Measurement precision

If autonomous lawn mowers use complex navigation systems to improve performance on diverse terrains, then the navigation precision and adaptability are improved, but the manufacturing cost increases

Engineering Contradiction:
Improvenavigation precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

Multiple sensing technologies (odometry, inertial measurement, optical surveying, and sonic detection) are merged into a single integrated navigation system that shares common processing resources and control architecture. This consolidation achieves high navigation precision across diverse terrains while reducing overall system cost compared to implementing separate independent systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The navigation system continuously self-calibrates and adapts to terrain variations using real-time sensor data. The inertial measurement unit compensates for odometry drift, while the optical and sonic modules automatically adjust to environmental conditions, reducing the need for expensive manual calibration and maintenance

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the docking module uses a fixed charging interface, then the device complexity is reduced, but the adaptability to vertical offsets and terrain variations decreases

Engineering Contradiction:
Improvedocking adaptabilityVSAvoiddocking mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The docking module employs a rotatable member that can dynamically adjust its position and orientation to accommodate vertical offsets between the mower body and docking station. This dynamic adjustment mechanism allows the charging interface to maintain proper alignment despite terrain variations or manufacturing tolerances, enhancing docking adaptability without requiring an overly complex mechanical system

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3858127B1An autonomous lawn mower and a system for navigating thereof
Publication Date: 2025.10.29 TECHTRONIC CORDLESS GP
  • EP3858127B1 patent drawingFigure 1
  • EP3858127B1 patent drawingFigure 2
  • EP3858127B1 patent drawingFigure 3

AI summary

An autonomous lawn mower comprising a mower body having at least one motor arranged to drive a cutting blade and to propel the mower body on an operating surface via a wheel arrangement, wherein the mower body includes a navigation system arranged to assist a controller to control the operation of the mower body within a predefined operating area and a docking station arranged to provide battery charging to the mower body. The docking station further includes a rotatable member arranged to contact the mower body and to compensate vertical offset between the docking station and the mower body.