Slow-Feature Metric Localization for Small Mobile Robots

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Solution Overview

Problem

Existing self-localization methods for mobile autonomous devices, such as small commercial robots, face challenges in accurately determining metric positions without external sensors, as they often rely on costly and cumbersome external sensors for ground truth measurements, and struggle with synchronization issues and computational efficiency.

Innovation Solution

A method that uses unsupervised learning, specifically Slow Feature Analysis (SFA), to generate environmental representations from onboard sensors, integrating displacement data from odometers to calculate mapping parameters, allowing for metric position estimation without external sensors, suitable for small robots like lawn mowers, and enhancing localization accuracy through data fusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If external sensors are used to generate ground truth metric position measurements, then position accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improveposition accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The mobile device uses its own onboard sensors (camera, odometer) to generate the environmental representation and learn mapping parameters, eliminating the need for external sensors. The system performs self-localization by fusing odometer displacement data with visual environmental representations, allowing the device to serve its own localization needs without external assistance.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent extracts and removes the dependency on external sensors from the localization system. By using only onboard sensors and odometer data, the system extracts the essential localization functionality without the complexity and cost of external sensing equipment, achieving self-contained operation.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If external sensors are used for ground truth measurements, then position accuracy is improved, but synchronization issues and computational complexity increase

Engineering Contradiction:
Improveposition accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the localization function with the environmental representation learning process. By combining odometer data with visual sensor data in a unified self-learning framework, the system eliminates the need for separate external sensors and their associated synchronization complexities, achieving integrated localization and mapping.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If SLAM algorithms are used for localization, then metric position information is obtained, but computational resources and processing time increase

Engineering Contradiction:
Improvemetric position informationVSAvoidcomputational efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent employs computationally efficient algorithms that require minimal processing resources compared to traditional SLAM. The approach uses simple environmental representations and lightweight mapping parameter learning that can be executed on resource-constrained devices, sacrificing some computational intensity for significantly improved efficiency and real-time performance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Device complexity

If topological SLAM algorithms are used, then metric relations are avoided, but localization precision in metric space is reduced

Engineering Contradiction:
Improvealgorithm simplicityVSAvoidmetric position accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the parameter representation from topological place classifications to metric coordinate systems. By learning mapping parameters that transform environmental representations into metric positions using odometer data, the system achieves both algorithmic simplicity and metric precision, bridging the gap between topological and metric approaches.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3534235B1Unsupervised learning of metric representations from slow features
Publication Date: 2021.04.14 HONDA RES INST EUROPE
  • EP3534235B1 patent drawingFigure 1
  • EP3534235B1 patent drawingFigure 2
  • EP3534235B1 patent drawingFigure 3(a)~3(c)

AI summary

A method of unsupervised learning of a metric representation and a corresponding system for a mobile device are proposed. The method determines a metric position information for a mobile device from an environmental representation. The mobile device comprises at least one sensor for acquiring sensor data and an odometer system configured to acquire displacement data of the mobile device. The method comprises a step of generating an environmental representation based on the acquired sensor data by applying an unsupervised learning algorithm. The mobile device moves along a trajectory and the displacement data and the sensor data are acquired while the mobile device is moving along the trajectory. In a step of calculating a set of mapping parameters, the set of mapping parameters is calculated based on the environmental representation and the displacement data. In a step of determining the metric position estimation, the metric position estimation is determined based on a further environmental representation and the calculated set of mapping parameters.