3 research outputs found
UAV/UGV Autonomous Cooperation: UAV Assists UGV to Climb a Cliff by Attaching a Tether
This paper proposes a novel cooperative system for an Unmanned Aerial Vehicle
(UAV) and an Unmanned Ground Vehicle (UGV) which utilizes the UAV not only as a
flying sensor but also as a tether attachment device. Two robots are connected
with a tether, allowing the UAV to anchor the tether to a structure located at
the top of a steep terrain, impossible to reach for UGVs. Thus, enhancing the
poor traversability of the UGV by not only providing a wider range of scanning
and mapping from the air, but also by allowing the UGV to climb steep terrains
with the winding of the tether. In addition, we present an autonomous framework
for the collaborative navigation and tether attachment in an unknown
environment. The UAV employs visual inertial navigation with 3D voxel mapping
and obstacle avoidance planning. The UGV makes use of the voxel map and
generates an elevation map to execute path planning based on a traversability
analysis. Furthermore, we compared the pros and cons of possible methods for
the tether anchoring from multiple points of view. To increase the probability
of successful anchoring, we evaluated the anchoring strategy with an
experiment. Finally, the feasibility and capability of our proposed system were
demonstrated by an autonomous mission experiment in the field with an obstacle
and a cliff.Comment: 7 pages, 8 figures, accepted to 2019 International Conference on
Robotics & Automation. Video: https://youtu.be/UzTT8Ckjz1
Enabling Large-scale Heterogeneous Collaboration with Opportunistic Communications
Multi-robot collaboration in large-scale environments with limited-sized
teams and without external infrastructure is challenging, since the software
framework required to support complex tasks must be robust to unreliable and
intermittent communication links. In this work, we present MOCHA (Multi-robot
Opportunistic Communication for Heterogeneous Collaboration), a framework for
resilient multi-robot collaboration that enables large-scale exploration in the
absence of continuous communications. MOCHA is based on a gossip communication
protocol that allows robots to interact opportunistically whenever
communication links are available, propagating information on a peer-to-peer
basis. We demonstrate the performance of MOCHA through real-world experiments
with commercial-off-the-shelf (COTS) communication hardware. We further explore
the system's scalability in simulation, evaluating the performance of our
approach as the number of robots increases and communication ranges vary.
Finally, we demonstrate how MOCHA can be tightly integrated with the planning
stack of autonomous robots. We show a communication-aware planning algorithm
for a high-altitude aerial robot executing a collaborative task while
maximizing the amount of information shared with ground robots. The source code
for MOCHA and the high-altitude UAV planning system is available open source:
http://github.com/KumarRobotics/MOCHA,
http://github.com/KumarRobotics/air_router.Comment: 7 pages, 8 figure