Decentralized Multi-Robot Consensus for Feature Distribution Mapping

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Solution Overview

Problem

Multi-robot systems face challenges in efficiently exploring and mapping unknown environments due to limitations in communication infrastructure, bandwidth constraints, and the need for centralized motion planning and localization, especially in scenarios with Markovian random mobility models and dynamic communication networks.

Innovation Solution

A decentralized, stochastic multi-robot exploration strategy using a consensus protocol that allows robots to update their feature distribution estimates through a distributed Chernoff fusion protocol, enabling consensus on a discrete distribution of static features without requiring constant communication or centralized connectivity, and validated through numerical and Software-In-The-Loop simulations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If centralized motion planning and localization are used in multi-robot systems, then coordination and control are improved, but communication bandwidth requirements and system complexity increase

Engineering Contradiction:
Improvecoordination and controlVSAvoidcommunication infrastructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the centralized control system into decentralized autonomous robots, where each robot independently performs motion planning and localization. The team-level coordination is segmented into local interactions through communication protocols, eliminating the need for a centralized communication infrastructure while maintaining coordination capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each robot in the multi-robot system performs self-localization and self-motion-planning using its own sensors and computational resources. This self-service approach eliminates dependency on centralized services, reducing communication bandwidth requirements and system complexity while maintaining reliable coordination through distributed consensus mechanisms.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If constant communication is implemented for feature distribution estimation, then consensus accuracy is improved, but communication bandwidth consumption increases

Engineering Contradiction:
Improveconsensus accuracyVSAvoidcommunication bandwidth
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent implements periodic communication intervals where robots exchange feature distribution estimates at discrete time steps rather than continuously. This periodic action maintains consensus accuracy by allowing sufficient information exchange while dramatically reducing communication bandwidth consumption compared to constant communication.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent uses partial action by implementing communication only when necessary - specifically when robots encounter each other or when certain convergence criteria are not met. This selective communication approach maintains adequate consensus accuracy while minimizing bandwidth usage by avoiding redundant information exchange.

Inventive Principle:
Principle #16Partial or excessive action

3Loss of information

If centralized connectivity is required for multi-robot exploration, then information sharing is improved, but system robustness under communication disruptions decreases

Engineering Contradiction:
Improveinformation sharingVSAvoidrobustness under communication disruptions
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent segments the information sharing mechanism into local robot-to-robot exchanges rather than centralized information flow. Each robot maintains its own feature distribution estimates and shares them with nearby robots through local communication, creating a robust distributed network that continues to function under communication disruptions without requiring centralized connectivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements recovery mechanisms where robots continue exploration and information gathering independently when communication is disrupted, discarding the need for constant centralized connectivity. When communication is restored, robots recover and exchange accumulated information, maintaining robustness against communication disruptions while ensuring eventual information sharing.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentUS20240096073A1Systems and methods for probabilistic consensus on feature distribution for multi-robot systems with markovian exploration dynamics
Publication Date: 2024.03.21 THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIV OF ARIZONA
  • US20240096073A1 patent drawing
  • US20240096073A1 patent drawing
  • US20240096073A1 patent drawing

AI summary

A consensus-based decentralized multi-robot approach is presented for reconstructing a discrete distribution of features, modeled as an occupancy grid map, that represent information contained in a bounded planar 2D environment, such as visual cues used for navigation or semantic labels associated with object detection. The robots explore the environment according to a random walk modeled by a discrete-time discrete-state (DTDS) Markov chain and estimate the feature distribution from their own measurements and the estimates communicated by neighboring robots, using a distributed Chernoff fusion protocol. Under this decentralized fusion protocol, each robot's feature distribution converges to the ground truth distribution in an almost sure sense.