1,848 research outputs found
Remote Tracking via Encoded Information for Nonlinear Systems
The problem addressed in this paper is to control a plant so as to have its
output tracking (a family of) reference commands generated at a remote location
and transmitted through a communication channel of finite capacity. The
uncertainty due to the presence of the communication channel is counteracted by
a suitable choice of the parameters of the regulator
Activity induced delocalization and freezing in self-propelled systems
We study a system of interacting active particles, propelled by colored
noises, characterized by an activity time {\tau}, and confined by a single-well
anharmonic potential. We assume pair-wise repulsive forces among particles,
modelling the steric interactions among microswimmers. This system has been
experimentally studied in the case of a dilute suspension of Janus particles
confined through acoustic traps. We observe that already in the dilute regime -
when inter-particle interactions are negligible - increasing the persistent
time pushes the particles away from the potential minimum, until a saturation
distance is reached. We compute the phase diagram (activity versus interaction
length), showing that the interaction does not suppress this delocalization
phenomenon but induces a liquid- or solid-like structure in the densest
regions. Interestingly a reentrant behavior is observed: a first increase of
{\tau} from small values acts as an effective warming, favouring fluidization;
at higher values, when the delocalization occurs, a further increase of {\tau}
induces freezing inside the densest regions. An approximate analytical scheme
gives fair predictions for the density profiles in the weakly interacting case.
The analysis of non-equilibrium heat fluxes reveals that in the region of
largest particle concentration equilibrium is restored in several aspects
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
Uniform Practical Nonlinear Output Regulation
International audienceIn this paper, we present a solution to the problem of asymptotic and practical semiglobal regulation by output feedback for nonlinear systems. A key feature of the proposed approach is that practical regulation is achieved uniformly with respect to the dimension of the internal model and to the gain of the stabilizer near the zero error manifold. This property renders the approach interesting for a number of real cases by bridging the gap between output regulation theory and advanced engineering applications. Simulation results regarding meaningful control problems are also presented
Consistent Query Answering for Expressive Constraints under Tuple-Deletion Semantics
We study consistent query answering in relational databases. We consider an
expressive class of schema constraints that generalizes both tuple-generating
dependencies and equality-generating dependencies. We establish the complexity
of consistent query answering and repair checking under tuple-deletion
semantics for different fragments of the above constraint language. In
particular, we identify new subclasses of constraints in which the above
problems are tractable or even first-order rewritable
A High-Gain Nonlinear Observer With Limited Gain Power
International audienceIn this note we deal with a new observer for nonlinear systems of dimension n in canonical observability form. We follow the standard high-gain paradigm, but instead of having an observer of dimension n with a gain that grows up to power n, we design an observer of dimension 2n − 2 with a gain that grows up only to power 2
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