Robust Sensor Fusion for SLAM Localization

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Solution Overview

Problem

Conventional methods for sensor fusion, such as particle filters, often fail to accurately update estimates of a robot's pose after kidnapping events due to limited sample representation and unknown statistical properties of measurements, leading to slow convergence or incorrect estimates, especially in environments with noisy or incomplete data.

Innovation Solution

The implementation of Visual Simultaneous Localization and Mapping (VSLAM) technologies using multiple particles to maintain multiple hypotheses, which combines data from visual sensors and dead reckoning sensors to create and update maps, allowing for robust recovery from kidnapping events by correcting drift in dead reckoning measurements with visual landmarks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a relatively large number of samples (particles) is used to improve estimation accuracy, then the estimation precision is improved, but the computational requirement increases significantly

Engineering Contradiction:
Improveestimation precisionVSAvoidcomputational requirement
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the particle filter algorithm into multiple parallel processors, where each processor handles a subset of particles. This segmentation allows the system to maintain high estimation precision with a large number of particles while distributing the computational load across multiple processors, thereby reducing the computational requirement on any single processor and enabling parallel computation.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the error in the initial estimate is large, then the system must handle kidnapping events, but the estimate converges slowly or not at all

Engineering Contradiction:
Improverecovery from kidnappingVSAvoidconvergence time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic particle management where the system adapts to large initial errors by dynamically adjusting particle distribution and weights. When kidnapping events are detected, the system dynamically resamples particles and redistributes them across the state space, enabling fast convergence even when the initial estimate is completely wrong. This dynamic adaptation allows reliable recovery from kidnapping within a short time frame.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the statistical properties of measurements are not known with accuracy, then the performance of particle filter breaks down, but using robust treatment allows faster and more reliable recovery

Engineering Contradiction:
Improverobustness to unknown statisticsVSAvoidprocessing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent employs parameter changes by adaptively adjusting particle weights, variances, and distribution parameters based on the observed measurement data rather than relying on pre-specified statistical properties. When measurements arrive, the system dynamically updates the particle parameters to match the actual data distribution, enabling robust performance even when initial statistical assumptions are incorrect. This adaptive parameter adjustment maintains processing efficiency while achieving reliable recovery.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS7689321B2Robust sensor fusion for mapping and localization in a simultaneous localization and mapping (SLAM) system
Publication Date: 2010.03.30 IROBOT CORP
  • US7689321B2 patent drawing
  • US7689321B2 patent drawing
  • US7689321B2 patent drawing

AI summary

This invention is generally related to methods and apparatus that permit the measurements from a plurality of sensors to be combined or fused in a robust manner. For example, the sensors can correspond to sensors used by a mobile device, such as a robot, for localization and/or mapping. The measurements can be fused for estimation of a measurement, such as an estimation of a pose of a robot.