Vision-Based Lawn Mower Navigation for Temporary Obstacle Avoidance

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Solution Overview

Problem

Existing autonomous lawn mowers rely on boundary wires for navigation, which cannot address temporary obstacles and periodic changes in a lawn, leading to potential damage from collision sensors that struggle with irregularities like dead grass patches or holes.

Innovation Solution

A vision-based navigation system using cameras and processors to analyze images in real-time, categorizing image sections as mowable or unmowable, and adjusting the lawn mower's course to avoid obstacles, allowing for continuous operation without the need for boundary wire revisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a boundary wire is used to define lawn bounds and identify permanent obstacles, then the autonomous lawn mower can navigate within bounds and avoid permanent obstacles, but the system cannot address temporary obstacles and periodic changes in the lawn

Engineering Contradiction:
Improvenavigation reliabilityVSAvoidadaptability to temporary obstacles
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The lawn area is divided into multiple image sections, with each section independently analyzed for mowable versus unmowable content. This segmentation allows the system to identify temporary obstacles in specific regions without being constrained by a fixed boundary wire layout.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mechanical boundary wire system is replaced with a vision-based navigation system using cameras and image processing. This substitution enables the system to detect both permanent and temporary obstacles through optical sensing rather than relying on physical wire boundaries.

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

2Adaptability or versatility

If a collision sensor is used to negotiate temporary obstacles, then the system can detect some irregularities, but over time this results in damage to the encountered obstacles or the lawn mower itself

Engineering Contradiction:
Improvedetection of temporary obstaclesVSAvoiddamage to obstacles and mower
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The vision system performs preliminary detection of obstacles before the lawn mower reaches them. By identifying temporary obstacles such as dead grass patches, holes, and seasonal ornaments in advance, the system can plan avoidance maneuvers that prevent collision and damage.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously captures images and processes them in real-time to provide feedback on the lawn conditions ahead. This feedback loop enables dynamic adjustment of the mower's path to avoid temporary obstacles while maintaining efficient mowing operations.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If the collision sensor is the primary method for detecting obstacles, then the system can operate without boundary wire revisions, but the collision sensor cannot sense many periodic irregularities like dead grass patches or holes

Engineering Contradiction:
Improvedetection capabilityVSAvoidobstacle detection reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system changes the detection parameter from mechanical contact (collision sensor) to optical sensing (camera). This parameter change enables the detection of various obstacle types including dead grass patches, holes, and seasonal ornaments that are invisible to collision sensors until contact occurs.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11849668B1Autonomous vehicle navigation
Publication Date: 2023.12.26 HYDRO GEAR LP
  • US11849668B1 patent drawing
  • US11849668B1 patent drawing
  • US11849668B1 patent drawing

AI summary

Autonomous vehicle navigation is disclosed. An example lawn mower includes a vision sensor configured to capture an image of an area being approached. The lawn mower includes a processor in communication with the vision sensor and configured to divide the image into a grid of separate image sections. Each of the image sections corresponds to a respective portion of the area being approached. For each of the image sections in the grid the processor is further configured to calculate a percentage of the image section categorized as corresponding with unmowable material and assign a result value based on a comparison between the calculated percentage and one or more movement thresholds. The lawn mower includes a drive system in communication with the processor and configured to control movement of the lawn mower based on an arrangement of the result values in the grid of the image sections.