Pool Robot Navigation Using In-Situ Gyroscope Magnetometer Alignment

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Solution Overview

Problem

Pool cleaning robots (PCRs) face challenges in navigating accurately without factory-calibrated magnetometers, as magnetic fields in factories differ from those in pools, and there is a need to direct them to an exit position without relying on factory calibration.

Innovation Solution

A method and platform that utilize a gyroscope and magnetometer, where the magnetometer is calibrated by determining a mapping between magnetometer readings and gyroscope-based direction estimates, with alignment iterations to ensure accurate navigation, allowing the PCR to find an exit point even without factory calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a factory calibrated magnetometer is used for navigation, then navigation accuracy is improved, but calibration cost and complexity increase

Engineering Contradiction:
Improvenavigation accuracyVSAvoidcalibration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-calibration by using the gyroscope as a reference to automatically align and calibrate the magnetometer in situ within the pool environment, eliminating the need for external factory calibration services

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The gyroscope is pre-aligned with the magnetometer before deployment, establishing a reference relationship that enables subsequent automatic calibration without requiring factory calibration of the magnetometer

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If a factory calibrated magnetometer is used for navigation, then navigation accuracy is improved, but adaptability to different pool environments deteriorates

Engineering Contradiction:
Improvenavigation accuracyVSAvoidenvironmental adaptability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system changes the calibration parameters by performing in-situ calibration within the specific pool environment, adjusting the magnetometer readings to account for local magnetic field characteristics rather than relying on factory calibration parameters from a different environment

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system automatically adapts to the local pool environment by performing self-calibration using the gyroscope reference, eliminating the mismatch between factory calibration environment and actual pool environment

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If in-situ calibration is performed, then calibration cost is reduced, but calibration time and process complexity increase

Engineering Contradiction:
Improvecalibration costVSAvoidcalibration time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The calibration process is merged with the normal operation timeline by performing calibration during the robot's deployment or idle periods in the pool, rather than requiring separate factory calibration sessions, thus utilizing existing time resources efficiently

Inventive Principle:
Principle #5Merging (Combining)

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

Enables the PCR to navigate effectively and find an exit point within the pool using a gyroscope-based direction estimate aligned with magnetometer readings, improving accuracy and reducing calibration costs, allowing for efficient operation without factory-calibrated magnetometers.

Implementation Method 1

A method and platform that utilize a gyroscope and magnetometer, where the magnetometer is calibrated by determining a mapping between magnetometer readings and gyroscope-based direction estimates

Methodology Applied
Scientific EffectGyroscope: Gyroscope

Implementation Method 2

A pool cleaning robot (PCR) may navigate within a pool using a magnetometer that is factory calibrated

Methodology Applied
Scientific EffectMagnetometer: Magnetometer

Data Source

PatentEP4311898A1Navigating a pool related platform
Publication Date: 2024.01.31 MAYTRONICS LTD
  • EP4311898A1 patent drawingFigure 1
  • EP4311898A1 patent drawingFigure 2
  • EP4311898A1 patent drawingFigure 3

AI summary

A method for navigating a movable pool related platform, PRP (10,200), the method includes moving the movable PRP along a home direction, wherein the movable PRP is associated with a gyroscope and with a magnetometer, wherein the moving is based on a gyroscope-based direction of movement estimate, wherein the gyroscope was aligned with the magnetometer. The magnetometer was calibrated during a calibration process that includes (i) determining, by a controller of the movable PRP, a mapping between magnetometer readings and a magnetometer-based direction of movement estimate; wherein the mapping is based, at least in part, on a first range of the first axis magnetometer readings and a second range of the second axis magnetometer readings; and (ii) performing an alignment iteration that comprises aligning, by the controller, between the magnetometer-based direction of movement estimate and the gyroscope-based direction of movement estimate.