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Lateral fligh control design for a highly flexible aircraft using a nonsmooth method
This paper describes a nonsmooth optimization technique for designing a lateral flight control law for a highly flexible aircraft. Flexible modes and high-dimensional models pose a major challenge to modern control design tools. We show that the nonsmooth approach offers potent and flexible alternatives in this difficult context. More specifically, the proposed technique is used to achieve a mix of frequency domain as well as time domain requirements for a set of different flight conditions
Discrete time optimal control with frequency constraints for non-smooth systems
We present a Pontryagin maximum principle for discrete time optimal control
problems with (a) pointwise constraints on the control actions and the states,
(b) frequency constraints on the control and the state trajectories, and (c)
nonsmooth dynamical systems. Pointwise constraints on the states and the
control actions represent desired and/or physical limitations on the states and
the control values; such constraints are important and are widely present in
the optimal control literature. Constraints of the type (b), while less
standard in the literature, effectively serve the purpose of describing
important spectral properties of inertial actuators and systems. The
conjunction of constraints of the type (a) and (b) is a relatively new
phenomenon in optimal control but are important for the synthesis control
trajectories with a high degree of fidelity. The maximum principle established
here provides first order necessary conditions for optimality that serve as a
starting point for the synthesis of control trajectories corresponding to a
large class of constrained motion planning problems that have high accuracy in
a computationally tractable fashion. Moreover, the ability to handle a
reasonably large class of nonsmooth dynamical systems that arise in practice
ensures broad applicability our theory, and we include several illustrations of
our results on standard problems
Multiobjective Robust Control with HIFOO 2.0
Multiobjective control design is known to be a difficult problem both in
theory and practice. Our approach is to search for locally optimal solutions of
a nonsmooth optimization problem that is built to incorporate minimization
objectives and constraints for multiple plants. We report on the success of
this approach using our public-domain Matlab toolbox HIFOO 2.0, comparing our
results with benchmarks in the literature
Alternatives with stronger convergence than coordinate-descent iterative LMI algorithms
In this note we aim at putting more emphasis on the fact that trying to solve
non-convex optimization problems with coordinate-descent iterative linear
matrix inequality algorithms leads to suboptimal solutions, and put forward
other optimization methods better equipped to deal with such problems (having
theoretical convergence guarantees and/or being more efficient in practice).
This fact, already outlined at several places in the literature, still appears
to be disregarded by a sizable part of the systems and control community. Thus,
main elements on this issue and better optimization alternatives are presented
and illustrated by means of an example.Comment: 3 pages. Main experimental results reproducible from files available
on http://www.mathworks.com/matlabcentral/fileexchange/33219 This work has
been submitted to the IEEE for possible publication. Copyright may be
transferred without notice, after which this version may no longer be
accessibl
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