1,728 research outputs found
Mean Square Capacity of Power Constrained Fading Channels with Causal Encoders and Decoders
This paper is concerned with the mean square stabilization problem of
discrete-time LTI systems over a power constrained fading channel. Different
from existing research works, the channel considered in this paper suffers from
both fading and additive noises. We allow any form of causal channel
encoders/decoders, unlike linear encoders/decoders commonly studied in the
literature. Sufficient conditions and necessary conditions for the mean square
stabilizability are given in terms of channel parameters such as transmission
power and fading and additive noise statistics in relation to the unstable
eigenvalues of the open-loop system matrix. The corresponding mean square
capacity of the power constrained fading channel under causal encoders/decoders
is given. It is proved that this mean square capacity is smaller than the
corresponding Shannon channel capacity. In the end, numerical examples are
presented, which demonstrate that the causal encoders/decoders render less
restrictive stabilizability conditions than those under linear
encoders/decoders studied in the existing works.Comment: Accepted by the 54th IEEE Conference on Decision and Contro
Stabilization over power-constrained parallel Gaussian channels
This technical note is concerned with state-feedback stabilization of multi-input systems over parallel Gaussian channels subject to a total power constraint. Both continuous-time and discrete-time systems are treated under the framework of H2 control, and necessary/sufficient conditions for stabilizability are established in terms of inequalities involving unstable plant poles, transmitted power, and noise variances. These results are further used to clarify the relationship between channel capacity and stabilizability. Compared to single-input systems, a range of technical issues arise. In particular, in the multi-input case, the optimal controller has a separation structure, and the lower bound on channel capacity for some discrete-time systems is unachievable by linear time-invariant (LTI) encoders/decoder
Dynamics and control of a class of underactuated mechanical systems
This paper presents a theoretical framework for the dynamics and control of underactuated mechanical systems, defined as systems with fewer inputs than degrees of freedom. Control system formulation of underactuated mechanical systems is addressed and a class of underactuated systems characterized by nonintegrable dynamics relations is identified. Controllability and stabilizability results are derived for this class of underactuated systems. Examples are included to illustrate the results; these examples are of underactuated mechanical systems that are not linearly controllable or smoothly stabilizable
Parameterization of Stabilizing Linear Coherent Quantum Controllers
This paper is concerned with application of the classical Youla-Ku\v{c}era
parameterization to finding a set of linear coherent quantum controllers that
stabilize a linear quantum plant. The plant and controller are assumed to
represent open quantum harmonic oscillators modelled by linear quantum
stochastic differential equations. The interconnections between the plant and
the controller are assumed to be established through quantum bosonic fields. In
this framework, conditions for the stabilization of a given linear quantum
plant via linear coherent quantum feedback are addressed using a stable
factorization approach. The class of stabilizing quantum controllers is
parameterized in the frequency domain. Also, this approach is used in order to
formulate coherent quantum weighted and control problems for
linear quantum systems in the frequency domain. Finally, a projected gradient
descent scheme is proposed to solve the coherent quantum weighted control
problem.Comment: 11 pages, 4 figures, a version of this paper is to appear in the
Proceedings of the 10th Asian Control Conference, Kota Kinabalu, Malaysia, 31
May - 3 June, 201
- …