Robot Cleaner Follow-Trajectory Control for Multi-Robot Separation

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Solution Overview

Problem

Existing mobile robot systems face challenges in efficient follow-up and collision avoidance when multiple robots move autonomously, particularly when their trajectories diverge or require communication through a server, leading to potential interruptions and inefficiencies.

Innovation Solution

Implementing a control method that allows mobile robots to communicate directly and adjust their speeds based on the length of the trajectory of a leading robot, ensuring they maintain a predetermined separation distance, thereby enabling uninterrupted and flexible follow-up movement without server intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the slave robot determines the position of the master robot through server communication, then the position information can be obtained, but the communication may be disconnected when located at places difficult to communicate with the server

Engineering Contradiction:
Improveposition determination reliabilityVSAvoidcommunication system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a dual communication architecture where the server acts as an intermediary for normal operations, but direct peer-to-peer communication between robots serves as a backup intermediary when server communication fails. This resolves the contradiction by providing multiple communication pathways without requiring a completely complex system redesign.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes communication parameters by switching between server-based communication and direct robot-to-robot communication based on connection status. When server communication is unavailable, the slave robot changes its communication mode to receive position information directly from the master robot, maintaining reliability without permanent system complexity.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the follower robot controls follow-up movement based on relative position distance, then the control is simple, but the follow-up is not efficient in exceptional situations where moving directions differ

Engineering Contradiction:
Improvefollow-up control simplicityVSAvoidcollaborative cleaning efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The follow-up control system dynamically adjusts its behavior based on real-time conditions. When the master and slave robots move in opposite directions or collision risk is detected, the slave robot dynamically changes from active following to pausing or avoidance, maintaining simple control logic while improving collaborative efficiency in exceptional situations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms where the slave robot continuously monitors the master robot's movement direction and position. When feedback indicates exceptional situations (opposite directions, potential collisions), the control algorithm adjusts follow-up behavior accordingly, balancing simplicity with efficiency through condition-based responses.

Inventive Principle:
Principle #23Feedback

3Productivity

If multiple robot cleaners perform collaborative cleaning, then the cleaning coverage increases, but the coordination and collision avoidance becomes more complex

Engineering Contradiction:
Improvecleaning coverageVSAvoidcoordination system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the navigation intelligence into a single master robot while slave robots perform simpler follow-up tasks. This combining of complex functions in one unit and simple functions in others allows multiple robots to work together for increased coverage without each robot needing full coordination capabilities, reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Slave robots copy the master robot's cleaning trajectory and behavior patterns rather than independently planning their own paths. This copying approach enables multiple robots to achieve coordinated cleaning coverage without complex inter-robot negotiation, as each slave simply replicates the master's proven effective cleaning pattern in its designated area.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3846981B1A robot cleaner and a controlling method for the same
Publication Date: 2024.11.06 LG ELECTRONICS INC
  • EP3846981B1 patent drawingFigure 1~2
  • EP3846981B1 patent drawingFigure 3~4
  • EP3846981B1 patent drawingFigure 5a~5b

AI summary

A mobile robot according to an embodiment of the present disclosure may include a moving unit configured to move a main body, a communication unit configured to communicate with another mobile robot that emits a signal, and a controller configured to recognize the position of the another mobile robot using the signal, and control the moving unit to follow a trajectory corresponding to the movement of the another mobile robot based on the recognized position. Furthermore, the controller may output a control command for changing a moving speed of the main body or the another mobile robot in response to whether a length of trajectory to be followed by the main body deviates from a predetermined range.