Collaborative Robot Manifold Tracking via Straddle Formation

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Solution Overview

Problem

Existing technologies face challenges in tracking coherent structures and manifolds in fluid flows, particularly in ocean environments, where sensors tend to escape due to the unstable nature of Lagrangian coherent structures, requiring effective methods for maintaining monitoring regions.

Innovation Solution

A collaborative control method using at least three autonomous sensors, where one sensor acts as a tracking sensor and the others as herding sensors, maintaining a straddle formation to predict global fluid flow structures based on local velocity measurements, enabling the tracking of stable and unstable manifolds in 2D conservative flows without requiring a global picture of ocean dynamics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If sensors are deployed to monitor Lagrangian coherent structures in ocean flows, then global information about flow dynamics can be obtained, but sensors tend to escape from monitoring regions due to the unstable nature of LCS

Engineering Contradiction:
Improveloss of global flow informationVSAvoidsensor position stability
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The system divides the monitoring task among multiple autonomous sensors (at least three) that operate cooperatively. Each sensor monitors a portion of the LCS while the team collectively maintains coverage of the entire coherent structure, preventing information loss while individual sensors remain within stable monitoring regions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system continuously measures local flow velocity and uses this feedback to dynamically adjust sensor positions. By computing LCS trajectories from velocity measurements and comparing current sensor positions to desired positions on the LCS, the system maintains sensors within monitoring regions despite the unstable nature of the coherent structures.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If autonomous sensors are used to track coherent structures, then measurement capabilities are improved, but device complexity increases due to collaborative control requirements

Engineering Contradiction:
ImproveLCS tracking accuracyVSAvoidcollaborative control system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Each autonomous sensor is equipped with onboard processing capabilities to compute local LCS trajectories and determine its own desired position on the coherent structure. The sensors independently calculate control commands based on local velocity measurements and shared position information, reducing the need for complex centralized control while maintaining high tracking accuracy.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If sensors maintain straddle formation across LCS boundaries, then boundary tracking precision is improved, but ease of operation deteriorates due to formation control requirements

Engineering Contradiction:
Improveboundary tracking precisionVSAvoidsensor deployment simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The straddle formation is not a rigid static configuration but a dynamic formation that adapts to the evolving LCS geometry. The desired positions of sensors on the LCS are continuously updated based on real-time velocity measurements and LCS trajectory computations, allowing the formation to maintain precision while automatically adjusting to flow changes without requiring manual reconfiguration.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS8972164B2Collaborative robot manifold tracker
Publication Date: 2015.03.03 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES
  • US8972164B2 patent drawing
  • US8972164B2 patent drawing
  • US8972164B2 patent drawing

AI summary

A collaborative control method for tracking Lagrangian coherent structures (LCSs) and manifolds on flows employs at least three autonomous sensors each equipped with a local flow sensor for sensing flow in a designated fluid medium, e.g. water or air. A first flow sensor is a tracking sensor while the other sensors are herding sensors for controlling and determining the actions of the tracking sensor. The tracking sensor is positioned with respect to the herding sensors in the fluid medium such that the herding sensors maintain a straddle formation across a boundary; obtaining a local fluid flow velocity measurement from each sensor. A global fluid flow structure is predicted based on the local flow velocity measurements. In a water medium, mobile autonomous underwater flow sensors may be deployed with each tethered to a watersurface craft.