Robotic Work Tool Exit Path Control for Trapped Navigation

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Solution Overview

Problem

Robotic work tools, such as lawnmowers, often become trapped in confined areas or unable to navigate obstacles, leading to incomplete or over-servicing of work areas due to insufficient navigation and obstacle detection systems.

Innovation Solution

The robotic work tool system determines a state of limited movement by analyzing factors like forced turns, distance traveled, collisions, and area confinement, and uses sensors and path analysis to identify an exit path, enabling it to escape such situations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the robotic work tool uses basic obstacle detection and navigation, then the device complexity is low, but the robotic work tool becomes trapped behind obstacles and cannot navigate complex environments effectively

Engineering Contradiction:
Improvenavigation reliabilityVSAvoidnavigation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary analysis of movement patterns and detects trapped states before they become critical problems. By monitoring forced turns, collision frequency, and area coverage metrics in advance, the robotic work tool can identify when it is becoming trapped and switch to exit mode proactively, rather than reacting after failing to complete its task.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors navigation performance metrics including forced turns, collisions, area coverage, and movement patterns. This feedback loop allows the robotic work tool to assess whether it is becoming trapped and dynamically adjust its behavior by switching between work mode and exit mode, improving navigation reliability through adaptive response.

Inventive Principle:
Principle #23Feedback

2Productivity

If the robotic work tool stays in work mode continuously, then productivity is high, but the robotic work tool may become trapped and over-service certain areas while missing others

Engineering Contradiction:
Improvework area servicing rateVSAvoidarea coverage completeness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system dynamically switches between two operational modes: work mode for normal productivity and exit mode for escaping trapped states. The control system adjusts the operational mode based on real-time analysis of movement patterns, forced turns, and area coverage metrics, allowing the robotic work tool to maintain high productivity during normal operation while ensuring complete and accurate area coverage by exiting trapped states when detected.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters by switching modes between work and exit operations. In work mode, the robotic work tool focuses on productivity with standard navigation parameters. When trapped state detection triggers mode switching, the system changes parameters to prioritize escape navigation, adjusting movement patterns, turn frequencies, and path selection to exit the confined area and resume comprehensive area coverage.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the robotic work tool frequently switches modes to check for trapped states, then the area coverage completeness improves, but the productivity decreases due to mode switching overhead

Engineering Contradiction:
Improvearea coverage accuracyVSAvoidwork completion efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary monitoring of navigation metrics continuously during work mode without interrupting productivity. Trap detection is based on accumulated data about forced turns, collisions, and area coverage patterns that are tracked in real-time. Only when thresholds are exceeded does the system switch to exit mode, minimizing interruptions while maintaining accurate trapped state detection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses continuous feedback from sensors and navigation metrics to monitor work performance and detect trapped states. The feedback mechanism analyzes forced turn frequency, collision rates, and area coverage completeness during normal operation, allowing the system to maintain high productivity while accurately detecting when mode switching is necessary to ensure complete area coverage.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4072261B1Exit path determination for a robotic work tool
Publication Date: 2025.10.08 HUSQVARNA AB
  • EP4072261B1 patent drawingFigure 1A~1B
  • EP4072261B1 patent drawingFigure 2~3
  • EP4072261B1 patent drawingFigure 4~5

AI summary

A robotic work tool system (200) comprising a robotic work tool (100), the robotic work tool (100) being configured to determine (410) that the robotic work tool (100) has entered a state of limited movement; determine (420) an exit path; and exit (430) the state of limited movement by navigating the exit path.