497 research outputs found
NEPTUNE: Non-Entangling Planning for Multiple Tethered Unmanned Vehicles
Despite recent progress on trajectory planning of multiple robots and path
planning of a single tethered robot, planning of multiple tethered robots to
reach their individual targets without entanglements remains a challenging
problem. In this paper, we present a complete approach to address this problem.
Firstly, we propose a multi-robot tether-aware representation of homotopy,
using which we can efficiently evaluate the feasibility and safety of a
potential path in terms of (1) the cable length required to reach a target
following the path, and (2) the risk of entanglements with the cables of other
robots. Then, the proposed representation is applied in a decentralized and
online planning framework that includes a graph-based kinodynamic trajectory
finder and an optimization-based trajectory refinement, to generate
entanglement-free, collision-free and dynamically feasible trajectories. The
efficiency of the proposed homotopy representation is compared against existing
single and multiple tethered robot planning approaches. Simulations with up to
8 UAVs show the effectiveness of the approach in entanglement prevention and
its real-time capabilities. Flight experiments using 3 tethered UAVs verify the
practicality of the presented approach.Comment: Accepted for publication in IEEE Transaction on Robotic
Attitude and Tension Control of a Tethered Formation of Aerial Vehicles
In this thesis we deal with the problem of formation control exploiting external constraints. In particular, we want to tether two quadrotors to each other and to a fixed point by ropes. Then, we want to control the quadrotors in order to drive the orientation of the formation, keeping the cables tautopenEmbargo per motivi di segretezza e/o di proprietĂ dei risultati e/o informazioni sensibil
Safety-Aware Human-Robot Collaborative Transportation and Manipulation with Multiple MAVs
Human-robot interaction will play an essential role in various industries and
daily tasks, enabling robots to effectively collaborate with humans and reduce
their physical workload. Most of the existing approaches for physical
human-robot interaction focus on collaboration between a human and a single
ground robot. In recent years, very little progress has been made in this
research area when considering aerial robots, which offer increased versatility
and mobility compared to their grounded counterparts. This paper proposes a
novel approach for safe human-robot collaborative transportation and
manipulation of a cable-suspended payload with multiple aerial robots. We
leverage the proposed method to enable smooth and intuitive interaction between
the transported objects and a human worker while considering safety constraints
during operations by exploiting the redundancy of the internal transportation
system. The key elements of our system are (a) a distributed payload external
wrench estimator that does not rely on any force sensor; (b) a 6D admittance
controller for human-aerial-robot collaborative transportation and
manipulation; (c) a safety-aware controller that exploits the internal system
redundancy to guarantee the execution of additional tasks devoted to preserving
the human or robot safety without affecting the payload trajectory tracking or
quality of interaction. We validate the approach through extensive simulation
and real-world experiments. These include as well the robot team assisting the
human in transporting and manipulating a load or the human helping the robot
team navigate the environment. To the best of our knowledge, this work is the
first to create an interactive and safety-aware approach for quadrotor teams
that physically collaborate with a human operator during transportation and
manipulation tasks.Comment: Guanrui Li and Xinyang Liu contributed equally to this pape
Folding Knots Using a Team of Aerial Robots
From ancient times, humans have been using cables and ropes to tie, carry,
and manipulate objects by folding knots. However, automating knot folding is
challenging because it requires dexterity to move a cable over and under
itself. In this paper, we propose a method to fold knots in midair using a team
of aerial vehicles. We take advantage of the fact that vehicles are able to fly
in between cable segments without any re-grasping. So the team grasps the cable
from the floor, and releases it once the knot is folded. Based on a composition
of catenary curves, we simplify the complexity of dealing with an
infinite-dimensional configuration space of the cable, and formally propose a
new knot representation. Such representation allows us to design a trajectory
that can be used to fold knots using a leader-follower approach. We show that
our method works for different types of knots in simulations. Additionally, we
show that our solution is also computationally efficient and can be executed in
real-time.Comment: International Conference on Intelligent Robots and Systems, IROS
2022, Kyoto, Japan, Oct 23 - Oct. 27, 202
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