252 research outputs found
6D physical interaction with a fully actuated aerial robot
This paper presents the design, control, and experimental validation of a novel fully-actuated aerial robot for physically interactive tasks, named Tilt-Hex. We show how the Tilt-Hex, a tilted-propeller hexarotor is able to control the full pose (position and orientation independently) using a geometric control, and to exert a full-wrench (force and torque independently) with a rigidly attached end-effector using an admittance control paradigm. An outer loop control governs the desired admittance behavior and an inner loop based on geometric control ensures pose tracking. The interaction forces are estimated by a momentum based observer. Control and observation are made possible by a precise control and measurement of the speed of each propeller. An extensive experimental campaign shows that the Tilt-Hex is able to outperform the classical underactuated multi-rotors in terms of stability, accuracy and dexterity and represent one of the best choice at date for tasks requiring aerial physical interaction
Design, Modeling, and Geometric Control on SE(3) of a Fully-Actuated Hexarotor for Aerial Interaction
In this work we present the optimization-based design and control of a
fully-actuated omnidirectional hexarotor. The tilt angles of the propellers are
designed by maximizing the control wrench applied by the propellers. This
maximizes (a) the agility of the UAV, (b) the maximum payload the UAV can hover
with at any orientation, and (c) the interaction wrench that the UAV can apply
to the environment in physical contact. It is shown that only axial tilting of
the propellers with respect to the UAV's body yields optimal results. Unlike
the conventional hexarotor, the proposed hexarotor can generate at least 1.9
times the maximum thrust of one rotor in any direction, in addition to the
higher control torque around the vehicle's upward axis. A geometric controller
on SE(3) is proposed for the trajectory tracking problem for the class of fully
actuated UAVs. The proposed controller avoids singularities and complexities
that arise when using local parametrizations, in addition to being invariant to
a change of inertial coordinate frame. The performance of the controller is
validated in simulation.Comment: 9 pages, 9 figures, ICRA201
Passive Compliance Control of Aerial Manipulators
This paper presents a passive compliance control for aerial manipulators to
achieve stable environmental interactions. The main challenge is the absence of
actuation along body-planar directions of the aerial vehicle which might be
required during the interaction to preserve passivity. The controller proposed
in this paper guarantees passivity of the manipulator through a proper choice
of end-effector coordinates, and that of vehicle fuselage is guaranteed by
exploiting time domain passivity technique. Simulation studies validate the
proposed approach.Comment: IEEE/RSJ International Conference on Intelligent Robots and Systems
(IROS) 201
Modelling, Analysis, and Control of OmniMorph: an Omnidirectional Morphing Multi-rotor UAV
This paper introduces for the first time the design, modelling, and control of a novel morphing multi-rotor Unmanned Aerial Vehicle (UAV) that we call the OmniMorph. The morphing ability allows the selection of the configuration that optimizes energy consumption while ensuring the needed maneuverability for the required task. The most energy-efficient uni-directional thrust (UDT) configuration can be used, e.g., during standard point-to-point displacements. Fully-actuated (FA) and omnidirectional (OD) configurations can be instead used for full pose tracking, such as, e.g., constant attitude horizontal motions and full rotations on the spot, and for full wrench 6D interaction control and 6D disturbance rejection. Morphing is obtained using a single servomotor, allowing possible minimization of weight, costs, and maintenance complexity. The actuation properties are studied, and an optimal controller that compromises between performance and control effort is proposed and validated in realistic simulations. Preliminary tests on the prototype are presented to assess the propellers’ mutual aerodynamic interference.</p
Modelling, Analysis and Control of OmniMorph: an Omnidirectional Morphing Multi-rotor UAV
This paper introduces for the first time the design, modelling, and control
of a novel morphing multi-rotor Unmanned Aerial Vehicle (UAV) that we call the
OmniMorph. The morphing ability allows the selection of the configuration that
optimizes energy consumption while ensuring the needed maneuverability for the
required task. The most energy-efficient uni-directional thrust (UDT)
configuration can be used, e.g., during standard point-to-point displacements.
Fully-actuated (FA) and omnidirectional (OD) configurations can be instead used
for full pose tracking, such as, e.g., constant attitude horizontal motions and
full rotations on the spot, and for full wrench 6D interaction control and 6D
disturbance rejection. Morphing is obtained using a single servomotor, allowing
possible minimization of weight, costs, and maintenance complexity. The
actuation properties are studied, and an optimal controller that compromises
between performance and control effort is proposed and validated in realistic
simulations
Multi-rotor Aerial Vehicles in Physical Interactions: A Survey
Research on Multi-rotor Aerial Vehicles (MAVs) has experienced remarkable
advancements over the past two decades, propelling the field forward at an
accelerated pace. Through the implementation of motion control and the
integration of specialized mechanisms, researchers have unlocked the potential
of MAVs to perform a wide range of tasks in diverse scenarios. Notably, the
literature has highlighted the distinctive attributes of MAVs that endow them
with a competitive edge in physical interaction when compared to other robotic
systems. In this survey, we present a categorization of the various types of
physical interactions in which MAVs are involved, supported by comprehensive
case studies. We examine the approaches employed by researchers to address
different challenges using MAVs and their applications, including the
development of different types of controllers to handle uncertainties inherent
in these interactions. By conducting a thorough analysis of the strengths and
limitations associated with different methodologies, as well as engaging in
discussions about potential enhancements, this survey aims to illuminate the
path for future research focusing on MAVs with high actuation capabilities
Voliro: An Omnidirectional Hexacopter With Tiltable Rotors
Extending the maneuverability of unmanned areal vehicles promises to yield a
considerable increase in the areas in which these systems can be used. Some
such applications are the performance of more complicated inspection tasks and
the generation of complex uninterrupted movements of an attached camera. In
this paper we address this challenge by presenting Voliro, a novel aerial
platform that combines the advantages of existing multi-rotor systems with the
agility of omnidirectionally controllable platforms. We propose the use of a
hexacopter with tiltable rotors allowing the system to decouple the control of
position and orientation. The contributions of this work involve the mechanical
design as well as a controller with the corresponding allocation scheme. This
work also discusses the design challenges involved when turning the concept of
a hexacopter with tiltable rotors into an actual prototype. The agility of the
system is demonstrated and evaluated in real- world experiments.Comment: Submitted to Robotics and Automation Magazin
Observer-based Controller Design for Oscillation Damping of a Novel Suspended Underactuated Aerial Platform
In this work, we present a novel actuation strategy for a suspended aerial
platform. By utilizing an underactuation approach, we demonstrate the
successful oscillation damping of the proposed platform, modeled as a spherical
double pendulum. A state estimator is designed in order to obtain the
deflection angles of the platform, which uses only onboard IMU measurements.
The state estimator is an extended Kalman filter (EKF) with intermittent
measurements obtained at different frequencies. An optimal state feedback
controller and a PD+ controller are designed in order to dampen the
oscillations of the platform in the joint space and task space respectively.
The proposed underactuated platform is found to be more energy-efficient than
an omnidirectional platform and requires fewer actuators. The effectiveness of
our proposed system is validated using both simulations and experimental
studies.Comment: 7 pages, 11 figures, Accepted for publication to ICRA 202
6D Pose Task Trajectory Tracking for a Class of 3D Aerial Manipulator From Differential Flatness
In this paper, the dynamics and control of a novel class of aerial manipulator for the purpose of end effector full pose trajectory tracking are investigated. The 6D pose of the end effector is set as a part of the flat output, from which the conditions that the system has the proposed flat output is obtained. The control law for the end effector tracking purpose is designed. The core part of the controller is an almost global controller in the configuration space of the system. From the transformation between the state space and the output space, the tracking control of the end effector in SE (3) is also achieved. The stability of the controlled system is analyzed. A numerical example is presented to demonstrate the theoretical analysis
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