Linear-Actuated Weeding Mechanism Without Soil Stirring

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Solution Overview

Problem

Existing weeding technologies, such as rotating saw discs and robotic arms with multiple degrees of freedom, are inefficient, costly, and prone to soil stirring or damage to crop plants, and require complex programming.

Innovation Solution

A weeding mechanism with a first and second shaft, independently movable sledges, and pivotable arms, allowing 2 degrees of freedom for precise weeding tool movement, using actuators like linear motors and drive belts for high-speed operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rotating saw discs are used for inter-row cutting, then weeding capability is provided, but soil stirring occurs which stimulates weed growth

Engineering Contradiction:

Improveweeding capabilityVSAvoidsoil stirring

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the rotating mechanical saw disc system with a linearly moving cutting tool driven by a linear actuator. This substitution eliminates the rotational motion that causes soil stirring while maintaining the cutting function through precise linear positioning and movement of the cutting tool along the crop row.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If rotating saw discs are used for weeding, then weeds are removed, but crop plants may be harmed when weeds grow close to crops

Engineering Contradiction:

Improveweed removalVSAvoidcrop damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The rotating saw disc system is replaced with a linearly actuated cutting tool that can be precisely positioned and controlled. The linear motion system allows for better control of cutting depth and position, enabling the tool to selectively remove weeds close to crops without damaging the crop plants through uncontrolled rotational contact.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the motion parameters from rotational to linear, and controls the position, speed, and depth parameters of the cutting tool. This allows dynamic adjustment of cutting parameters to adapt to varying distances between weeds and crops, preventing crop damage while maintaining effective weed removal.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If a robotic arm with multiple degrees of freedom is used for weeding, then flexible weeding action is achieved, but system cost and programming complexity increase significantly

Engineering Contradiction:

Improveweeding flexibilityVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The complex multi-degree-of-freedom robotic arm system is replaced with a simpler linear actuation system. The linear actuator directly drives the cutting tool along a linear path, providing sufficient flexibility for weeding operations without requiring complex multi-axis robotic mechanisms, thereby reducing system cost and programming complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If a robotic arm with multiple degrees of freedom is used for weeding, then positioning capability is improved, but control complexity and programming requirements increase

Engineering Contradiction:

Improvepositioning precisionVSAvoidcontrol complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the complex robotic arm control system with a simpler linear actuator control system. The linear actuator provides precise positioning of the cutting tool through direct linear motion control, eliminating the need for complex multi-joint coordination and extensive robot programming while maintaining adequate positioning precision for weeding operations.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables precise weeding without soil stirring and crop damage, simplifies programming, and reduces costs compared to robotic arms, with the ability to perform 6-7 cutting sequences per second.

Implementation Method 1

The actuator is arranged to move the horizontal shaft along its axis so that the cutting tool is moved in a linear motion relative to the platform

Methodology Applied

Scientific EffectLinear motion:

Implementation Method 2

The drive belt is a timing belt

Methodology Applied

Scientific EffectMechanical force transmission:

Data Source

PatentUS12422436B2Weeding mechanism and a weeding vehicle including the weeding mechanism

Publication Date: 2025.09.23 EKOBOT AB

AI summary

The present invention relates to a weeding mechanism (1) for an autonomous weeding vehicle, and a weeding vehicle including the weeding mechanism. The weeding mechanism comprises a first shaft (3), a second shaft (5) arranged spaced apart from the first shaft (3), a first sledge (7) linearly movable along the first shaft (3), a second sledge (9) linearly movable along the second shaft (5), first and second actuators (11, 13) arranged to independently move the first and second sledges (7, 9) along the first and second shafts (3, 5) respectively, a first arm (15) pivotably connected to the first sledge (7), a second arm (17) pivotably connected to the second sledge (9) and pivotably connected to the first arm (15), and a weeding tool (2) operatively connected to at least one of the first and second arms (15, 17).