Mobile Robot Position Reset Using Boundary Signal Homing

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Solution Overview

Problem

Existing moving robots face challenges in accurately recognizing their position outdoors due to wheel slip and varying friction, leading to accumulated errors over time, and require additional sensors to define traveling paths, which increases complexity and cost.

Innovation Solution

A moving robot system that includes a body with a traveler, a boundary signal detector, an azimuth sensor, and a controller to reset its position by returning to a charging station, using a single sensor to recognize boundaries and correct its path without additional sensors, by detecting magnetic field differences to define and maintain its traveling area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If Dead Reckoning (Odometer + AHRS) is used to recognize position, then the robot can estimate its position without additional sensors, but accumulated error occurs over time due to wheel slip and friction diversity

Engineering Contradiction:
Improvesensor configurationVSAvoidposition recognition accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by having the robot periodically return to the charging station to correct its position. The charging station serves as a reference point that provides feedback on the robot's actual position, allowing the system to reset accumulated errors from Dead Reckoning and maintain long-term positioning accuracy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by pre-establishing the charging station as a fixed reference point in the environment. This reference point is set up in advance to enable periodic position correction, allowing the robot to maintain accurate positioning without requiring complex real-time sensor systems.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If additional sensors are added to define traveling paths, then position recognition accuracy improves, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveposition recognition accuracyVSAvoidsensor configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The boundary signal detector is designed to perform multiple functions: it detects both the boundary signals that define the traveling area and the charging station signals that provide position correction references. This multi-functionality eliminates the need for separate sensors for path definition and position recognition, reducing device complexity while maintaining accuracy.

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

Solution Approach 2:

The robot uses its own boundary signal detector to simultaneously perform boundary detection and position correction tasks. By making the single sensor self-sufficient for multiple functions, the system avoids the need for additional specialized sensors, thereby reducing complexity and manufacturing costs.

Inventive Principle:
Principle #25Self-service

3Productivity

If the robot operates continuously without returning to charging station, then productivity increases, but position error accumulates over time

Engineering Contradiction:
Improvework efficiencyVSAvoidposition recognition accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements periodic action by scheduling regular returns to the charging station at predetermined time intervals or after completing specific work areas. This periodic homing allows the robot to maintain high productivity by limiting the duration between position corrections, thereby controlling accumulated error without requiring constant returns.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The working area is divided into multiple sub-areas that can be completed sequentially. The robot is designed to return to the charging station after completing each sub-area, segmenting the overall work into manageable portions. This segmentation allows for periodic position correction while maintaining overall productivity by minimizing idle time between work segments.

Inventive Principle:
Principle #1Segmentation

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

The system allows for accurate position recognition and reduced positional errors, preventing damage to the environment while reducing manufacturing costs and controller complexity by using a single sensor for boundary recognition and homing.

Implementation Method 1

a boundary signal detector which detects a boundary signal generated in a boundary of a traveling area and a docking position signal generated in a docking device

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

a controller which generates control signals for controlling the traveler, based on the boundary signal and the docking position signal

Methodology Applied
Scientific EffectMagnetic field control: Magnetic Field

Data Source

PatentEP3778145B1Mobile robot and control method of mobile robot
Publication Date: 2024.05.29 LG ELECTRONICS INC
  • EP3778145B1 patent drawingFigure 1
  • EP3778145B1 patent drawingFigure 2
  • EP3778145B1 patent drawingFigure 3

AI summary

According to a moving robot and a control method of a moving robot of the present disclosure, it is possible to reset a position of the moving robot by returning to a charging station after completing a work in one traveling zone and continuously perform a work.