6,322 research outputs found
Model predictive control techniques for hybrid systems
This paper describes the main issues encountered when applying model predictive control to hybrid processes. Hybrid model predictive control (HMPC) is a research field non-fully developed with many open challenges. The paper describes some of the techniques proposed by the research community to overcome the main problems encountered. Issues related to the stability and the solution of the optimization problem are also discussed. The paper ends by describing the results of a benchmark exercise in which several HMPC schemes were applied to a solar air conditioning plant.Ministerio de Eduación y Ciencia DPI2007-66718-C04-01Ministerio de Eduación y Ciencia DPI2008-0581
Flexible Lyapunov Functions and Applications to Fast Mechatronic Systems
The property that every control system should posses is stability, which
translates into safety in real-life applications. A central tool in systems
theory for synthesizing control laws that achieve stability are control
Lyapunov functions (CLFs). Classically, a CLF enforces that the resulting
closed-loop state trajectory is contained within a cone with a fixed,
predefined shape, and which is centered at and converges to a desired
converging point. However, such a requirement often proves to be
overconservative, which is why most of the real-time controllers do not have a
stability guarantee. Recently, a novel idea that improves the design of CLFs in
terms of flexibility was proposed. The focus of this new approach is on the
design of optimization problems that allow certain parameters that define a
cone associated with a standard CLF to be decision variables. In this way
non-monotonicity of the CLF is explicitly linked with a decision variable that
can be optimized on-line. Conservativeness is significantly reduced compared to
classical CLFs, which makes \emph{flexible CLFs} more suitable for
stabilization of constrained discrete-time nonlinear systems and real-time
control. The purpose of this overview is to highlight the potential of flexible
CLFs for real-time control of fast mechatronic systems, with sampling periods
below one millisecond, which are widely employed in aerospace and automotive
applications.Comment: 2 figure
Safety Control Synthesis with Input Limits: a Hybrid Approach
We introduce a hybrid (discrete--continuous) safety controller which enforces
strict state and input constraints on a system---but only acts when necessary,
preserving transparent operation of the original system within some safe region
of the state space. We define this space using a Min-Quadratic Barrier
function, which we construct along the equilibrium manifold using the Lyapunov
functions which result from linear matrix inequality controller synthesis for
locally valid uncertain linearizations. We also introduce the concept of a
barrier pair, which makes it easy to extend the approach to include
trajectory-based augmentations to the safe region, in the style of LQR-Trees.
We demonstrate our controller and barrier pair synthesis method in
simulation-based examples.Comment: 6 pages, 7 figures. Accepted for publication at the 2018 American
Controls Conference. Copyright IEEE 201
Stabilizing control for power converters connected to transmission lines
This paper proposes a switching control strategy for the set-point stabilization of a power converter connected via a transmission line to a resistive load. The strategy employs a Lyapunov function that is directly based on energy considerations of the power converter, as well as of the transmission line described by the telegraph equations. The proposed stabilizing switching control still allows a certain freedom in the choice of the control law, a comparison between a maximum descent strategy and a minimum commutation strategy being discussed on a simple example.
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