Multi-Robot Cleaner Follow-Up Control Without Server Communication

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Solution Overview

Problem

Existing mobile robot systems struggle to efficiently follow each other without interference or collision, especially when the leading robot changes its moving direction, and they often require communication through a server, which can be unreliable in certain environments.

Innovation Solution

The system allows mobile robots to recognize each other's relative positions through signals and follow each other's moving paths without server communication. When the leading robot changes its direction, the system transmits signals to inform the following robot, allowing for collision-free avoidance and continuous follow-up.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the master robot transmits relative position information to the slave robot through the server using WLAN technology, then communication between robots is established, but communication may be disconnected when robots are located where it is difficult to communicate with the server

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidcommunication system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces a dual communication mode where robots can communicate directly with each other (peer-to-peer) as an intermediary solution when server-based communication is unavailable. The slave robot uses its obstacle detection device to directly sense and determine the master robot's position, bypassing the server intermediary when necessary.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes communication parameters by switching between server-based WLAN communication and direct robot-to-robot sensing based on server availability. When server communication is disconnected, the system transitions to using the obstacle detection device for position determination, changing the operational mode to maintain reliability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the leading cleaner changes its moving direction frequently to clean a designated cleaning space, then cleaning coverage is improved, but collision problems with the following cleaner may occur

Engineering Contradiction:
Improvecleaning efficiencyVSAvoidcollision avoidance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The following robot continuously receives position information from the master robot and adjusts its own position and speed in real-time based on this feedback. When the master robot changes direction, the slave robot detects this through the obstacle detection device and modifies its trajectory accordingly, preventing collisions while maintaining follow-up.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The slave robot performs preliminary position adjustments before the master robot completes its direction change. By continuously monitoring the master robot's position data and proactively adjusting its own position, the slave robot prevents collision scenarios before they occur.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the slave robot determines the position of the master robot using obstacle detection device, then the slave robot can know the master robot's position without server communication, but the master robot cannot determine the position of the slave robot

Engineering Contradiction:
Improveposition determination reliabilityVSAvoidmutual position recognition
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent combines multiple sensing approaches: the master robot uses its obstacle detection device to detect the slave robot, while the slave robot uses its own obstacle detection device to detect the master robot. This merging of detection capabilities enables mutual position recognition without requiring server communication.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3787459B1A plurality of robot cleaner and a controlling method for the same
Publication Date: 2025.06.04 LG ELECTRONICS INC
  • EP3787459B1 patent drawingFigure 1
  • EP3787459B1 patent drawingFigure 2
  • EP3787459B1 patent drawingFigure 3

AI summary

A mobile robot according to an embodiment of the present disclosure may include a traveling 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 location of the another mobile robot based on the signal, and control the moving of the another mobile robot to follow along a moving path of the main body based on the recognized location. In addition, the controller may transmit a signal corresponding to a change of the moving direction to the main body in response to the change of the moving direction, and sense a change in the receiving direction of the signal according to the change of moving direction to transmit a control command for restricting the follow-up to the another mobile robot.