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\begin{document}

\wikidoc{file=Proj.ModEstUSV}
\wikidoc{auth=tpaine@mit.edu}


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\section*{Ensemble methods for online estimation of dynamical models for marine vehicles}
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In this (side) project we investigated using an ensemble of three
different methods for online system identification for dynamical
models of marine vehicle motion. The three methods were a contracting
recurrent neural network (RNN), adaptive identifier (AID) and
recursive least squares (RLS).  For the RNN, we designed and
implemented a new term in the loss function to encourage learning a
stable RNN in the sense of contraction stability.  The ensemble was
implemented onboard 8 Heron USVs and ran as a background process in
the summer and fall of 2022 for a total of more than 30 hrs of run
time.  Overall the results were promising, and the best result was
that the ensemble on each of the 8 vehicles learned a unique model,
and that model was uniquely optimized for that particular
vehicle. Given the initial success, we aim to apply these methods
towards fault identification and mitigation in addition to using the
model to better inform autonomous decision making.  More details can
be found at

\begin{figure}[ht]
  \centering 
  \includegraphics[width=0.95\textwidth]{figures/modestusv.png}
\label{fig_modestusv}
\caption{Eight Heron Unmanned Surface Vehicles (USVs) made by
  Clearpath Robotics were used for field testing. Inset: Block diagram
  of online ensemble estimation using adaptive identifier (AID),
  recursive least squares (RLS), and recurrent neural network (RNN)
  approaches.}
\end{figure}

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%\section*{Quick Facts}
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\begin{longtable}{|r|p{0.76\textwidth}|} \hline

  \var{Status}: &amp; Ongoing since January 2023 \\ \hline
  \var{Sponsor(s)}: &amp; In-House \\ \hline
  \var{People}: &amp; Tyler Paine, Mike Benjamin \\ \hline
  \var{Robots}: &amp;  \urlx{https://oceanai.mit.edu/pavlab/robots/herons} \\ \hline
  \var{Software:} &amp; MOOS-IvP public codebase, MOOS-IvP-Pavlab codebase \\ \hline
%  \var{Photos:} &amp; \urlx{https://oceanai.mit.edu/media/WestPoint2022/album} \\ \hline
\end{longtable}
\normalsize


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\section*{Recent Publications}

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