Autonomous Mower Surface Recognition for Boundary-Free Steering

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Solution Overview

Problem

Autonomous lawnmowers face inefficiencies and safety hazards when navigating without boundary wires, as they struggle to determine their position and direction relative to the working area, leading to prolonged operation times and potential mechanical wear.

Innovation Solution

An autonomous lawnmower system with a surface recognition module and control module that determines the position and angle relationship with the boundary by detecting surface types, allowing the lawnmower to steer efficiently and safely within the working area without physical boundaries, using drive wheels controlled by independent motors to adjust speed and direction for precise navigation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the autonomous lawnmower travels along random paths and steers randomly when encountering obstacles or boundary wires, then the lawnmower can avoid obstacles and stay within working area, but it takes a long time to leave narrow areas and may fail to leave, causing increased mechanical wear and shorter service life

Engineering Contradiction:
Improveservice lifeVSAvoidtime to leave narrow area
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The lawnmower uses a surface recognition module to detect surface characteristics and provide feedback about its position relative to the boundary. The control module processes this feedback to determine the angle relationship with the boundary and calculates an optimal steering angle, enabling intelligent navigation that adapts to the working area geometry rather than random movement

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the navigation parameter from random steering angles to calculated optimal steering angles based on detected surface characteristics. By computing the angle between the lawnmower's moving direction and the boundary, the system determines precise steering commands that efficiently exit narrow areas while maintaining safety margins

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the boundary wire is arranged at a distance from the actual boundary according to manual guidance, then the autonomous lawnmower can ensure working safety and prevent traveling beyond safety boundary, but it is complex and inconvenient for the user to arrange the boundary wire

Engineering Contradiction:
Improveworking safetyVSAvoidease of arranging boundary wire
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The invention extracts and removes the boundary wire from the system, replacing it with a surface recognition module that detects surface characteristics to identify the working area boundary. This eliminates the need for users to physically arrange boundary wires while maintaining safety through automated surface-based boundary detection

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical boundary wire system is replaced with an optical/electronic surface recognition system. The surface recognition module detects surface characteristics (such as color, texture, or reflectivity differences) to identify boundaries, substituting the mechanical boundary definition with sensor-based detection

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

3Device complexity

If the autonomous lawnmower cannot know its original traveling direction and exact position in the working area, then the lawnmower can operate without position sensors, but it cannot appropriately determine the preferred steering direction, leading to inefficient navigation

Engineering Contradiction:
Improveposition sensing systemVSAvoidnavigation efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

Instead of implementing a complete position and orientation sensing system, the invention uses partial information from surface recognition to determine the angle relationship with the boundary. This partial information is sufficient to calculate optimal steering angles and navigate efficiently without requiring full state awareness

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3798781B1Automatic mower and control method
Publication Date: 2024.05.01 POSITEC POWER TOOLS (SUZHOU) CO LTD
  • EP3798781B1 patent drawingFigure 1
  • EP3798781B1 patent drawingFigure 2
  • EP3798781B1 patent drawingFigure 3

AI summary

The present invention relates to an autonomous lawnmower, walking and working in a working area, and including: a housing, a walking module, and a surface recognition module, detecting a surface walked by the autonomous lawnmower, a detection area of the surface recognition module including a surface in front of the walking module, a surface in the working area being a working surface, a surface outside the working area being a non-working surface, a boundary of the working area being formed between the working surface and the non-working surface; and a control module, determining a position relationship between the autonomous lawnmower and the boundary according to a signal sent by the surface recognition module, if a preset position relationship is met, enabling the walking module to perform steering to travel into the working area, where if a moving direction forms an acute angle with the boundary in the clockwise direction, steering is clockwise, so that when steering is completed, the moving direction forms an acute angle with the boundary in the clockwise direction, and vice versa. Beneficial effects of the present invention are as follows: The autonomous lawnmower can work safely and efficiently for a boundary-less working area.