Multi-Robot Boundary Navigation for Reliable Position Estimation

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Solution Overview

Problem

Conventional autonomous travel-type vacuum cleaners face challenges in determining appropriate travel paths, particularly when estimating their position in environments without clear reference objects, leading to potential failures in navigation.

Innovation Solution

A mobile body system comprising at least three mobile bodies, each equipped with a storage for map information, a distance measuring sensor, and a controller, where two mobile bodies act as reference points and one as a steerable body, allowing the system to estimate its position and move through multiple areas by sequentially entering and exiting boundary areas between them.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a single mobile body uses distance measuring sensor for position estimation, then position estimation is possible, but position estimation fails in environments without clear reference objects

Engineering Contradiction:

Improveposition estimation accuracyVSAvoidnavigation reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces other mobile bodies as intermediary reference objects. Instead of relying on environmental reference objects, the system uses relatively stationary mobile bodies within the measurement range as mediators for position estimation. This allows the distance measuring sensor to obtain reliable distance information even in environments without clear external reference objects.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates virtual reference objects by using the known positions and distance measurements of other mobile bodies. Each mobile body effectively copies the reference object function from the environment, allowing position estimation to proceed without relying on actual environmental features.

Inventive Principle:

Principle #26Copying

2Area of stationary object

If multiple mobile bodies move simultaneously, then coverage area increases, but position estimation becomes unreliable due to movement

Engineering Contradiction:

Improvecoverage areaVSAvoidposition estimation accuracy

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent implements a dynamic role assignment system where mobile bodies switch between reference body and steerable body roles based on their movement states. When a mobile body moves, it transitions from reference body to steerable body, allowing the system to adapt to changing conditions while maintaining reliable position estimation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent requires mobile bodies to stop movement before serving as reference bodies for position estimation. This preliminary action of stopping ensures that reference bodies remain relatively stationary during measurement, guaranteeing reliable distance information while still allowing multiple bodies to cover large areas over time.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If mobile bodies continuously operate, then productivity increases, but electric power consumption increases

Engineering Contradiction:

Improveoperational continuityVSAvoidelectric power consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic operation cycles where mobile bodies alternate between moving phases (steerable body) and stationary phases (reference body). During reference body phases, power consumption is reduced while maintaining system productivity through coordinated operation of multiple bodies.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent enables mobile bodies to serve dual functions: they are both steerable bodies performing tasks and reference bodies aiding position estimation. This self-service capability allows a single mobile body to contribute to both productivity and system navigation, reducing the need for dedicated reference bodies and optimizing power usage.

Inventive Principle:

Principle #25Self-service

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 approach enables the mobile body system to navigate in a more appropriate travel path, avoiding position estimation failures and extending operational time by leveling electric power consumption, while allowing for easier area setup and minimizing interference from reference bodies.

Implementation Method 1

a position of the mobile body estimated based on distance information obtained by the distance measuring sensor

Methodology Applied

Scientific EffectTime of Flight: Time of Flight

Data Source

PatentUS11231722B2Mobile body system and control method

Publication Date: 2022.01.25 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

Provided is a mobile body system capable of moving in a more appropriate travel path. In the mobile body system, upon movement of the first to third mobile bodies from the first area into the second area, (a) the third mobile body moves into a boundary area and temporarily stops using the distance to the first mobile body and the distance to the second mobile body, (b) after the third mobile body moves into the boundary area, the first mobile body moves into the boundary area and temporarily stops using the distance to the second mobile body and the distance to the third mobile body, and (c) after the third mobile body moves into the boundary area, the second mobile body moves into the boundary area and temporarily stops using the distance to the first mobile body and the distance to the third mobile body.