1,946 research outputs found
Output Regulation for Systems on Matrix Lie-group
This paper deals with the problem of output regulation for systems defined on
matrix Lie-Groups. Reference trajectories to be tracked are supposed to be
generated by an exosystem, defined on the same Lie-Group of the controlled
system, and only partial relative error measurements are supposed to be
available. These measurements are assumed to be invariant and associated to a
group action on a homogeneous space of the state space. In the spirit of the
internal model principle the proposed control structure embeds a copy of the
exosystem kinematic. This control problem is motivated by many real
applications fields in aerospace, robotics, projective geometry, to name a few,
in which systems are defined on matrix Lie-groups and references in the
associated homogenous spaces
Bearing Rigidity Theory: characterization and control of mixed formations and localization
The bearing rigidity theory is applied to mixed formations composed by agents having heterogeneous domains. Necessary and sufficient conditions are provided for the characterization of infinitesimally bearing rigid formations. The stabilization problem for such formations is addressed and a distributed solution proposed and validated through simulations. A location recovery algorithm for fully-actuated formations embedded in SE(3) is presented along with analytical proofs.ope
A Unified Dissertation on Bearing Rigidity Theory
This work focuses on the bearing rigidity theory, namely the branch of
knowledge investigating the structural properties necessary for multi-element
systems to preserve the inter-units bearings when exposed to deformations. The
original contributions are twofold. The first one consists in the definition of
a general framework for the statement of the principal definitions and results
that are then particularized by evaluating the most studied metric spaces,
providing a complete overview of the existing literature about the bearing
rigidity theory. The second one rests on the determination of a necessary and
sufficient condition guaranteeing the rigidity properties of a given
multi-element system, independently of its metric space
Nonlinear Feedback Control of Axisymmetric Aerial Vehicles
We investigate the use of simple aerodynamic models for the feedback control
of aerial vehicles with large flight envelopes. Thrust-propelled vehicles with
a body shape symmetric with respect to the thrust axis are considered. Upon a
condition on the aerodynamic characteristics of the vehicle, we show that the
equilibrium orientation can be explicitly determined as a function of the
desired flight velocity. This allows for the adaptation of previously proposed
control design approaches based on the thrust direction control paradigm.
Simulation results conducted by using measured aerodynamic characteristics of
quasi-axisymmetric bodies illustrate the soundness of the proposed approach
Trajectory Optimization Through Contacts and Automatic Gait Discovery for Quadrupeds
In this work we present a trajectory Optimization framework for whole-body
motion planning through contacts. We demonstrate how the proposed approach can
be applied to automatically discover different gaits and dynamic motions on a
quadruped robot. In contrast to most previous methods, we do not pre-specify
contact switches, timings, points or gait patterns, but they are a direct
outcome of the optimization. Furthermore, we optimize over the entire dynamics
of the robot, which enables the optimizer to fully leverage the capabilities of
the robot. To illustrate the spectrum of achievable motions, here we show eight
different tasks, which would require very different control structures when
solved with state-of-the-art methods. Using our trajectory Optimization
approach, we are solving each task with a simple, high level cost function and
without any changes in the control structure. Furthermore, we fully integrated
our approach with the robot's control and estimation framework such that
optimization can be run online. By demonstrating a rough manipulation task with
multiple dynamic contact switches, we exemplarily show how optimized
trajectories and control inputs can be directly applied to hardware.Comment: Video: https://youtu.be/sILuqJBsyK
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