81,817 research outputs found
MoDem-V2: Visuo-Motor World Models for Real-World Robot Manipulation
Robotic systems that aspire to operate in uninstrumented real-world
environments must perceive the world directly via onboard sensing. Vision-based
learning systems aim to eliminate the need for environment instrumentation by
building an implicit understanding of the world based on raw pixels, but
navigating the contact-rich high-dimensional search space from solely sparse
visual reward signals significantly exacerbates the challenge of exploration.
The applicability of such systems is thus typically restricted to simulated or
heavily engineered environments since agent exploration in the real-world
without the guidance of explicit state estimation and dense rewards can lead to
unsafe behavior and safety faults that are catastrophic. In this study, we
isolate the root causes behind these limitations to develop a system, called
MoDem-V2, capable of learning contact-rich manipulation directly in the
uninstrumented real world. Building on the latest algorithmic advancements in
model-based reinforcement learning (MBRL), demo-bootstrapping, and effective
exploration, MoDem-V2 can acquire contact-rich dexterous manipulation skills
directly in the real world. We identify key ingredients for leveraging
demonstrations in model learning while respecting real-world safety
considerations -- exploration centering, agency handover, and actor-critic
ensembles. We empirically demonstrate the contribution of these ingredients in
four complex visuo-motor manipulation problems in both simulation and the real
world. To the best of our knowledge, our work presents the first successful
system for demonstration-augmented visual MBRL trained directly in the real
world. Visit https://sites.google.com/view/modem-v2 for videos and more
details.Comment: 9 pages, 8 figure
An Omnidirectional Aerial Manipulation Platform for Contact-Based Inspection
This paper presents an omnidirectional aerial manipulation platform for
robust and responsive interaction with unstructured environments, toward the
goal of contact-based inspection. The fully actuated tilt-rotor aerial system
is equipped with a rigidly mounted end-effector, and is able to exert a 6
degree of freedom force and torque, decoupling the system's translational and
rotational dynamics, and enabling precise interaction with the environment
while maintaining stability. An impedance controller with selective apparent
inertia is formulated to permit compliance in certain degrees of freedom while
achieving precise trajectory tracking and disturbance rejection in others.
Experiments demonstrate disturbance rejection, push-and-slide interaction, and
on-board state estimation with depth servoing to interact with local surfaces.
The system is also validated as a tool for contact-based non-destructive
testing of concrete infrastructure.Comment: Accepted submission to Robotics: Science and Systems conference 2019.
9 pages, 12 figure
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