Autonomous Lawnmower Wheel Control for Mechanical Weed Suppression

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Solution Overview

Problem

Existing autonomous lawn-mowing devices lack the capability to effectively control weeds in a lawn area, necessitating manual intervention by gardeners, and existing weed control methods for such devices are either chemically hazardous, mechanically complex, or require additional hardware, which is undesirable for private use.

Innovation Solution

An autonomous work device equipped with sensors and a control circuit navigates to detected weeds, positions its wheels on the target location, and performs a predetermined movement pattern to mechanically suppress weed growth without additional hardware or chemicals, using its existing drive wheels to slow weed growth relative to desirable plants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical herbicides are used for weed control, then weed suppression effectiveness is improved, but safety and environmental harm worsen

Engineering Contradiction:
Improveweed suppression effectivenessVSAvoidchemical safety
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces chemical herbicide application with a mechanical weed control system. The autonomous lawnmower uses its driving wheels to mechanically stress and suppress weed growth through controlled movement patterns, eliminating the need for chemical substances while maintaining effective weed control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The lawnmower performs weed control as a byproduct of its primary mowing function. The same driving wheels used for propulsion also serve as the weed control mechanism, and the mowing process itself disturbs and suppresses weed growth, allowing the system to control weeds without requiring separate dedicated hardware or chemicals.

Inventive Principle:
Principle #25Self-service

2Reliability

If mechanical weeding tools are used, then weed control capability is improved, but device complexity and energy consumption worsen

Engineering Contradiction:
Improveweed control capabilityVSAvoidtool complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the lawnmower's driving wheels multi-functional by using them both for propulsion and as the primary weed control mechanism. The wheels mechanically stress weeds through their movement and positioning actions, eliminating the need for separate mechanical weeding tools while maintaining effective weed control capability.

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

Solution Approach 2:

The patent combines the weed control function with the existing mowing and propulsion functions of the lawnmower. By integrating weed control into the driving and mowing operations rather than adding separate tools, the system achieves effective weed suppression without increasing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If manual weed detection and removal is performed, then weed control precision is improved, but labor time and productivity worsen

Engineering Contradiction:
Improveweed detection accuracyVSAvoidgardening efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent incorporates sensors that detect weeds and provide feedback to the control circuit. The control circuit processes this information and automatically adjusts the lawnmower's driving behavior to target and suppress detected weeds, enabling autonomous precision weed control without requiring manual inspection or intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs automated weed detection and control, eliminating the need for manual gardeners to inspect and remove weeds. The lawnmower autonomously identifies weed locations through sensors and independently executes weed suppression actions, significantly reducing labor time while maintaining precise weed control.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If additional weed control hardware is added to the lawnmower, then weed control functionality is improved, but device simplicity and cost worsen

Engineering Contradiction:
Improveweed control functionalityVSAvoidhardware simplicity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent achieves weed control functionality by repurposing the lawnmower's existing driving wheels for dual purposes: propulsion and weed suppression. This approach adds no hardware complexity while providing effective weed control, as the wheels' movement patterns are controlled to mechanically stress and suppress weed growth.

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

Solution Approach 2:

The lawnmower uses its own propulsion system as the weed control mechanism, eliminating the need for additional dedicated hardware. The driving wheels, already present for movement, are controlled to perform weed suppression functions, maintaining device simplicity while adding versatile weed control capability.

Inventive Principle:
Principle #25Self-service

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

Effectively suppresses weeds by mechanically stressing them without additional hardware or chemicals, ensuring safety in shared spaces with humans and reducing the need for manual inspection, while maintaining the autonomy and simplicity of the lawn-mowing device.

Implementation Method 1

an autonomous work device may use cameras and 3-dimensional (3D) sensors in order to detect and locate weeds

Methodology Applied
Scientific EffectImage recognition: Image Processing

Implementation Method 2

perform a predetermined movement pattern to mechanically suppress weed growth without additional hardware or chemicals, using its existing drive wheels to slow weed growth

Methodology Applied
Scientific EffectMechanical stress: Mechanical Force

Data Source

PatentEP4388839B1Weed control with an autonomous work device
Publication Date: 2026.02.25 HONDA MOTOR CO LTD
  • EP4388839B1 patent drawingFigure 1
  • EP4388839B1 patent drawingFigure 2
  • EP4388839B1 patent drawingFigure 3

AI summary

A weed control method for an autonomous work device is proposed, wherein the autonomous work device comprises driving means configured to move the autonomous work device in an outdoor environment. The autonomous work device further comprises sensor means configured to sense an environment of the autonomous work device and to generate a sensor signal based on the sensed environment, and a control circuit configured to control the driving means to navigate the autonomous work device in the environment based on the sensor signal. The weed control method comprises a step of obtaining a location of a target plant in the environment. The control circuit controls the driving means in a weed suppression mode, to position at least one wheel of the driving means on the computed location of the target plant and to perform a predetermined movement pattern of the autonomous work device while simultaneously maintaining the at least one wheel in an area at the location of the target plant.