Cooperative Inchworm Localization with a Low Cost Heterogeneous Team

Brian Nemsick

EECS Department
University of California, Berkeley
Technical Report No. UCB/EECS-2017-25
May 1, 2017

http://www2.eecs.berkeley.edu/Pubs/TechRpts/2017/EECS-2017-25.pdf

In this thesis we address the problem of multi-robot localization with a heterogeneous team of low-cost mobile robots. The team consists of a single centralized “observer” with an inertial measurement unit (IMU) and monocular camera, and multiple “picket” robots with only IMUs and Red Green Blue (RGB) light emitting diodes (LED). This team cooperatively navigates a visually featureless environment such as a collapsed building. A combination of camera imagery captured by the observer, as well as IMU measurements on the pickets and observer are fused to estimate motion of the team. A team movement strategy, referred to as inchworm, is formulated as follows; pickets move ahead of the observer and then act as temporary landmarks for the observer to follow. This cooperative approach employs a single Extended Kalman Filter (EKF) to localize the entire heterogeneous multi-robot team, using a formulation of the measurement Jacobian to relate the pose of the observer to the poses of the pickets with respect to the global reference frame. An initial experiment with the inchworm strategy has shown localization within 0.14 m position error and 2.18 degree orientation error over a path-length of 5 meters in an environment with irregular ground, partial occlusions and a ramp. This demonstrates improvement over a camera only relative pose measurement localization technique that was adapted to our team dynamic which produced 0.18m position error and 3.12 degree orientation error over the same dataset.

Advisor: Avideh Zakhor


BibTeX citation:

@mastersthesis{Nemsick:EECS-2017-25,
    Author = {Nemsick, Brian},
    Title = {Cooperative Inchworm Localization with a Low Cost Heterogeneous Team},
    School = {EECS Department, University of California, Berkeley},
    Year = {2017},
    Month = {May},
    URL = {http://www2.eecs.berkeley.edu/Pubs/TechRpts/2017/EECS-2017-25.html},
    Number = {UCB/EECS-2017-25},
    Abstract = {In this thesis we address the problem of multi-robot localization with a heterogeneous team
of low-cost mobile robots. The team consists of a single centralized “observer” with an
inertial measurement unit (IMU) and monocular camera, and multiple “picket” robots with
only IMUs and Red Green Blue (RGB) light emitting diodes (LED). This team cooperatively
navigates a visually featureless environment such as a collapsed building. A combination
of camera imagery captured by the observer, as well as IMU measurements on the pickets
and observer are fused to estimate motion of the team. A team movement strategy, referred
to as inchworm, is formulated as follows; pickets move ahead of the observer and then act
as temporary landmarks for the observer to follow. This cooperative approach employs
a single Extended Kalman Filter (EKF) to localize the entire heterogeneous multi-robot
team, using a formulation of the measurement Jacobian to relate the pose of the observer to
the poses of the pickets with respect to the global reference frame. An initial experiment
with the inchworm strategy has shown localization within 0.14 m position error and 2.18 degree
orientation error over a path-length of 5 meters in an environment with irregular ground,
partial occlusions and a ramp. This demonstrates improvement over a camera only relative
pose measurement localization technique that was adapted to our team dynamic which
produced 0.18m position error and 3.12 degree orientation error over the same dataset.}
}

EndNote citation:

%0 Thesis
%A Nemsick, Brian
%T Cooperative Inchworm Localization with a Low Cost Heterogeneous Team
%I EECS Department, University of California, Berkeley
%D 2017
%8 May 1
%@ UCB/EECS-2017-25
%U http://www2.eecs.berkeley.edu/Pubs/TechRpts/2017/EECS-2017-25.html
%F Nemsick:EECS-2017-25