Plurality of autonomous mobile robots and controlling method for the same

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Solution Overview

Problem

Existing autonomous mobile robots face challenges in performing seamless follow-up control and determining relative positions without relying on server communication, particularly when communication with the server is disrupted, and they lack the ability to accurately determine the direction of one robot with respect to another.

Innovation Solution

The implementation of a system where a first mobile robot is equipped with transmitting optical sensors and a UWB module, and a second mobile robot is equipped with receiving optical sensors and another UWB module, allowing the second robot to calculate the angle and distance of the first robot using light and UWB signals to determine their relative position.

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 an optical sensor as an intermediary communication channel between robots. When server-based WLAN communication is unavailable, the master robot emits optical signals that the slave robot's optical sensors can detect, enabling direct peer-to-peer communication without requiring server infrastructure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically switches communication parameters between WLAN (when server is accessible) and optical sensing (when server is inaccessible). This parameter change allows the communication system to adapt to different environmental conditions and maintain reliability across varying scenarios.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the master robot determines its position related to the slave robot using obstacle detection device position data, then the master robot can locate the slave robot, but the slave robot cannot determine the position of the master robot

Engineering Contradiction:
Improveposition determination precisionVSAvoidbidirectional position recognition
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements unidirectional optical signal transmission from master to slave, which is sufficient for the slave robot to determine the master's position. This partial action approach simplifies the system while achieving the necessary functionality without requiring complex bidirectional optical transmission.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The slave robot uses optical sensors to detect light from the master robot and feeds back position information to determine relative positioning. This feedback mechanism enables the slave robot to accurately locate the master robot based on optical signal characteristics.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If only obstacle detection devices are used for position determination, then the system can detect adjacent obstacles, but it is impossible to determine whether robots are located at the front or rear of each other

Engineering Contradiction:
Improverelative position measurementVSAvoiddirectional information loss
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent places optical sensors at specific locations on the slave robot to detect the direction of incoming light from the master robot. By strategically positioning sensors and analyzing which sensors receive the strongest signals, the system can determine directional information such as whether the master robot is in front or behind.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system adds an optical dimension to the existing obstacle detection capabilities. While obstacle detection provides basic proximity information, the optical sensors add directional and positional dimensions, enabling comprehensive spatial awareness including front-rear orientation determination.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Measurement precision

If multiple sensors are used for follow-up control, then accurate position determination is achieved, but the cost and device complexity increase

Engineering Contradiction:
Improveposition and angle calculation precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges two different sensing modalities: optical sensors for angle determination and UWB modules for distance measurement. By combining these technologies, the system achieves comprehensive 2D position and orientation determination without requiring multiple sensors of the same type, thus balancing precision with complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical sensors serve multiple functions: detecting the master robot's position, determining directional orientation (front/rear), and enabling communication when WLAN is unavailable. This multi-functionality reduces the need for separate specialized sensors for each function.

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

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

This solution enables accurate determination of relative positions between mobile robots, reducing costs and ensuring seamless follow-up control regardless of server communication state, by using a combination of infrared sensors and UWB modules for precise distance and angle calculations.

Implementation Method 1

a second mobile robot provided with a plurality of receiving optical sensors for receiving light and a second module for transmitting and receiving an Ultra-Wideband (UWB) signal

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

both mobile robots have modules for transmitting and receiving an Ultra-Wideband (UWB) signal

Methodology Applied
Scientific EffectElectromagnetic Radiation: Electromagnetic Induction

Data Source

PatentEP3787463B1Plurality of autonomous mobile robots and controlling method for the same
Publication Date: 2024.01.24 LG ELECTRONICS INC
  • EP3787463B1 patent drawingFigure 1
  • EP3787463B1 patent drawingFigure 2
  • EP3787463B1 patent drawingFigure 3~4

AI summary

A plurality of autonomous mobile robots include a first mobile robot and a second mobile robot. The first mobile robot is provided with a plurality of transmitting optical sensors for outputting light and a first module for transmitting and receiving a Ultra-Wideband (UWB) signal. The second mobile robot is provided with a plurality of receiving optical sensors for receiving light and a second module for transmitting and receiving the UWB signal. A control unit of the second mobile robot determines an angle at which the first mobile robot is located with respect to a front of the second mobile robot using the light. The control unit also determines a distance from the second mobile robot to the first mobile robot using the UWB signal, and determines a relative position of the first mobile robot based on the angle and the distance.