Fernando Castaños was born in Mexico City in 1976. He received the bachelor's degree in Electric and
Electronic Engineering from Universidad Nacional Autónoma de México(UNAM). He received the master degree in Control Engineering
from UNAM and the Ph.D. degree from Université Paris-Sud XI(UPS).
He was a postdoctoral fellow at McGill'sCenter for intelligent
machines(CIM) for two years. He currently works at
the Automatic Control Department, Cinvestav, México. He
is an editor for the Int. J. Robust Nonlinear Control.
Passivity-based control, nonlinear control, port-Hamiltonian systems, implicit systems, neuromorphic engineering,
robust control and variable structure systems.
(very) Short Introduction to control engineering
Control theory is a field that originates from electrical and mechanical engineering
and mathematics. The field has also found its way in other technical areas such as biology,
especially in neurobiology and physiology, medical technology, agricultural science,
economics, and computer science.
Control theory is concerned with problems associated with the dynamic behavior of systems.
These problems are about open systems, that is, systems with inputs and outputs, systems
interacting with their environment. Some essential problems driving modern-day research in
systems and control theory are:
The modeling problem: The search for suitable concepts and mathematical tools to describe dynamical systems
in interaction with their environment.
The identification problem: Developing algorithms for determining dynamic models based on observations
of signals.
The filtering problem: Reconstructing the behavior of a variable from observations of signals subject to noise.
The control problem: Devising principles and algorithms to obtain a good controller or feedback processor.
The last problem is the link with control engineering, the applied side of the research.
The control problem (classical view)
Based on the obtained measurements, how to calculate the inputs that will drive the system as desired?
Swing-up and stabilization of an inverted pendulum
Undergraduate thesis
An experimental setup was built for swinging up and stabilizing the well-known inverted pendulum.
Part of the work consisted of writing the DAC and ADC card drivers and interfacing them with Matlab's
Real-Time Workshop.
Swing up
A heuristic algorithm that forced the pendulum to oscillate at its resonance frequency was used to swing
up the pendulum. Once the pendulum reached a neighborhood of the upright position, the controller switched
to a stabilization algorithm consisting of an observer and a friction estimator cascaded with a linear
quadratic regulator.
Rolando Carrera
supervised the thesis (in Spanish).
Stabilization
Sliding-mode control
Master thesis, sliding-mode control (SMC) with an H_{∞} criterion
It is well known that sliding modes are robust to matched
perturbations and model uncertainties. That is, they are robust in the face of perturbations
that are coupled to the control action. On the other hand, sliding modes suffer from:
An initial period (called the reaching phase) in which the system's
robustness is not guaranteed.
Sensitivity to unmatched perturbations.
Full-state measurement is required.
The so-called chattering phenomenon.
The first problem can be solved using integral sliding modes, which has the
additional advantage of furnishing more design parameters. The extra freedom can then
be used to minimize, e.g., using an H_{∞} criterion, the impact of the
unmatched perturbations and uncertainties [CF06a,
CXF06, REC^{+}11,
CHZF14].
It is sometimes possible to enforce the desired sliding motion by constructing
a dynamic surface using only partial state information
[CF04b], regardless of any matched uncertainty (this
addresses the third problem). The input-to-state stability framework can be used to
efficiently compute the controller gains [MCF14,
MCF15, MCF16].
In the presence of unmatched uncertainties, one can also design the dynamic surface
using an H_{∞} criterion
[CF11, MCF13].
The machinery developed fits nicely in a decentralized control scenario
[CF05a].
The well-known pole-placement formula by Ackermann was modified by Utkin and Ackermann himself
to place the eigenvalues of the sliding dynamics in conventional
SMC. The formula can be further generalized to the case of
higher-order sliding modes [HZCF14, CCF16]. The formula can
be used as part of a higher-order sliding-mode control design methodology, achieving high
accuracy and robustness at the same time.
Extremum seeking
Tracking a varying maximum or minimum (extremum) of a performance (output, cost) function is
called extremum-seeking control. It usually has two layers of control. The first layer is an
algorithm able to control (stabilize) the system and drive the performance output
to its reference. The second layer sets the appropriate reference by seeking an extremum of
the performance output.
In some applications, the reference-to-output map has an extremum and the objective is to select
the set-point that keeps the output at the extremum value. The uncertainty in the reference-to-output
map makes it necessary to use some sort of adaptation to find the set point that optimizes the output.
Usually, the adaptation scheme requires a dither signal to satisfy the so-called persistence of
excitation. In [CK15], a nonsmooth ditherless extemum seeker is applied
to minimize hydrogen consumption in fuel cells. See also
[KC13a, KC13b].
Discrete-time sliding-mode control
From a purely theoretical point of view, the solution of a system that exhibits sliding motions
is, in fact, a solution of a differential inclusion set forth by Filippov's
theory on differential equations with discontinuous
right-hand sides. Ideally, this solution is absolutely continuous and exhibits no chattering.
In applications, chattering results from the presence of nonideal components, like actuators
with a nonzero time constant, or control laws implemented in discrete time. However, if the control law
is discretized using an implicit Euler scheme, the system results in a difference inclusion (as opposed
to the difference equation obtained with traditional methods), and chattering is substantially
suppressed [MBC18].
Discontinuous switching surfaces
In conventional sliding-mode control, insensitivity to matched disturbances originates
from the piecewise-smooth nature of the closed-loop system. It is natural
to expect a certain degree of robustness also to unmatched disturbances
if the switching surface is itself nonsmooth. One can find results on the properties
of systems with sigmoidal switching surfaces, but the limiting case of a true discontinuous
switching surface has remained elusive.
A set-valued approach from the outset shows the well-posedness
and the limiting behavior of a planar piece-wise smooth system having a discontinuous
switching surface [MBC19]. The system is subject to both matched and unmatched disturbances.
The approach leads to a single nonsmooth Lyapunov function that decreases along the reaching,
the sliding, and the oscillatory phases of the system trajectories. The implicit Euler
discretization of the controller leads to a robust controller with reduced chattering.
Homogeneous control of homogeneous systems with nonholonomic constraints
The main theoretical challenge in the face of a system with nonholonomic constraints is that,
even though such systems are controllable, they fail Brockett's test and hence are not
stabilizable by continuous static feedback laws. Many mechanical systems with nonholonomic constraints can
be written in the well-known chained or power forms. When written in these forms:
the Lie algebras generated by the system vector fields are nilpotent (so easily computed),
the controllability rank condition is easily verified,
the system representation is homogeneous,
and the failure of Brockett's test is readily exposed.
A two-stage homogeneity-preserving controller is presented in [RCM22].
By imposing a negative degree, finite-time stability is attained. The homogeneity of the power form
also lends itself to the application of the generalized circle criterion [RMC18],
from which absolute stability is achieved. An explicit homogeneous control Lyapunov function is instrumental
in the design of the controller.
The design strategy is tried out on a perturbed kinematic model of a car.
Passivity-based control
Passivity is a particular instance of dissipativity, a system-theoretic property
that relates different notions of stability (see the
diagram
for details).
PhD thesis, control by interconnection
Within a passivity framework, the control problem is approached by
using the notion of energy-shaping as the main design principle and
exploiting the physical properties of the plant.
The basic steps are:
Derive an energy-based model (e.g., Euler-Lagrange, port-Hamiltonian, Brayton-Moser,
etc). Energy-based models are simpler and intuitive; they also provide a dissipation
inequality, that can be used as a starting point.
Using the energy conservation property, design a controller that
“shapes” the system's energy as required. (The requirement of having a
physical interpretation of the controller usually simplifies this task.)
Add damping to improve the transient response.
It is well known that many mechanical and electro-mechanical systems can be described
using port-Hamiltonian models. Besides, a large class or RLC nonlinear circuits can also be put
in port-Hamiltonian form, provided their graphs satisfy some conditions
[CJOGC09]. This class of systems can be asymptotically stabilized
with a nonlinear proportional-integral controller [JOGCC07].
Implicit port-Hamiltonian models are developed in [CGHM13], and
the interconnection and damping assignment (IDA) control technique is developed for implicit port-Hamiltonian
models in [CG16]. A linear matrix inequality framework for under-actuated
mechanical systems is presented in [CCR19].
Energy shaping can be accomplished via standard passivity-based techniques like
energy-balance [CO09] or interconnection and damping
assignment [OvdSCA08, CG15]. Alternatively, one may reformulate
the control problem in a control-by-interconnection
setting [COvdSA09], where the original system and
the controller are viewed as energy ports that are interconnected in order to produce
the desired behavior.
Jan Willems' behavioral approach to systems and control is particularly well suited
for developing passivity-based control theory. The results presented in the
thesis are stated within the behavioral
framework. Romeo Ortega
supervised the thesis.
Passivity-based control of delayed systems
Passivity-based control (PBC) schemes usually take advantage of the following property: the interconnection of two passive
systems is again passive. This property ceases to hold when delays are part of the interconnection
structure (e.g., as in the case of two systems that are interconnected employing a communication channel).
A linear transformation can be applied to the Telegrapher's equations (which define a passive system)
in order to obtain a pair of uncoupled transport equations (which define a pair of delays). In the context of
robot telemanipulation, Anderson and Spong proposed to modify a communication channel, modeled as
a pair of delays, by applying the inverse transformation, so that the transformed channel is passive and
the overall interconnected system is again passive.
In the context of set-point regulation, Anderson's transformation performance is evaluated in terms
of achievable σ-stability. Using a frequency domain approach, analytic formulae
for optimal control parameters are derived [CEMR18].
Set-valued PBC
The renowned robustness of sliding-mode control can be understood in terms of the
signum function's multivalued nature. According to Filippov's theory,
robustness originates from the fact that a signum function appearing on the
right-hand side of a differential equation takes values on the power
set of the real line (as opposed to the real line itself).
It is shown in [MC17, MC15, MC14]
that it is possible to achieve similar (or sometimes better) robust controllers
with the use of other multivalued functions. In the references mentioned above,
the robust output regulation of passive linear systems is achieved using
set-valued, maximally monotone passive controllers. The results are extended to nonlinear Lagrangian
systems in [MBC17a] and formulated in the port-Hamiltonian framework in
[Cas22].
Locally port-Hamiltonian Systems
There are systems that possess a local but non-global port-Hamiltonian representation, non-globality being a
consequence of the phase-space topology. Locally port-Hamiltonian systems may transgress the dissipation inequality
satisfied by their global counterparts but, far from being a defect, non-globality extends the modeling power of
port-Hamiltonian systems by providing a framework to model cyclic physical processes for energy conversion and extraction
[CG21]. An example of such physical process is the Stirling engine described in [GC20].
Implicit systems
Implicit systems are described by mathematical models in which the state's derivative
is determined implicitly by a function whose arguments are: the state, the derivative itself,
and the control. The class of implicit (or descriptor) models
contains the class of state-space models, in which the state's derivative is given explicitly
as a function of the state and the control (i.e., vector fields). Implicit models can be used, e.g.,
to describe systems that perform a derivative action on the input, a feature that cannot be
captured by state-space models. In [CHZF14]
we apply integral sliding-mode control to linear descriptor systems to reject matched perturbations.
Eigenvalue assignment using conventional sliding-mode control is considered in [HZCF16].
In contrast with classical state-space systems, one has to take special care on the
differentiability of the control action (otherwise, a solution to the system equations might not exist).
For a restricted class of systems it is possible to suitably eliminate some of the state variables
and transform a given implicit model into an explicit one. Even when possible, in principle,
it might be preferable to work directly with an implicit model in some cases. In the specific context of Hamiltonian systems, going from an implicit representation
to an explicit one entails an effective reduction on the number of state variables, but complicates the Hamiltonian (Energy)
function substantially. Implicit representations are of higher dimension and, depending on the particular application, may
require us to solve for variables defined implicitly. On the other hand, the corresponding Hamiltonian functions have simpler
expressions. More precisely, it is possible to split the Hamiltonian functions into two terms: one depending on the momenta only
(the kinetic energy) and one depending on the positions only (the potential energy), i.e., the Hamiltonians are separable.
This property has been largely exploited in numerical simulations, resulting in self-correcting numerical simulation
algorithms and discrete-time sampled-data models. When applying the interconnection and damping assignment PBC methodology
to a Hamiltonian system, the resulting partial differential equations are simplified considerably if the kinetic energy does
not depend on the positions. Thus, there are possible advantages in using implicit representations in a control context as well.
The relationship between implicit and explicit port-Hamiltonian models can be understood in terms of commutative diagrams.
See [CGHM13] for details and, in particular, the explicit maps for going from one representation
to the other. The interconnection and damping assignment (IDA) control technique is developed for implicit port-Hamiltonian
models in [CG16]. A linear matrix inequality framework for under-actuated
mechanical systems is presented in [CCR19].
Bifurcations and singularities
Roughly speaking, a bifurcation is a change in the qualitative (topological) structure of the solutions of a
dynamical system as a parameter varies.
A bifurcation occurs, e.g., when the number of equilibria changes, which
in turn occurs when the number of solutions of an equation changes.
The study and classification of such equations can be accomplished using
singularity theory, a theory that rests heavily upon a topological and
differentiable notion of equivalence.
A neuromorphic electronic circuit
While the brain's inner-workings are still mostly unknown, the behavior of a single neuron
is relatively well-understood from the perspective of dynamical systems theory. By applying
singularity theory on a neuron's critical manifolds, we designed an electronic circuit that
mimics such manifolds, and can smoothly transition between the two
main neuronal operating modes: tonic spiking and bursting [CF17].
The resulting circuit solely uses six transistors and passive elements. For comparison,
the simplest available neuromorphic circuit capable of transitioning between tonic
spiking and bursting uses fourteen MOSFET transistors. Another advantage of our approach
is that the circuit parameters are constructively tuned by geometric inspection of its static
input-output characteristic, which avoids laborious and non-constructive parameter fitting
procedures.
Bifurcations occurring on a Stirling engine
The Stirling engine is an external combustion thermodynamic engine that operates by cyclic expansion
and contraction of a working fluid (typically air). Due to their high efficiency and capability of operating at
low temperatures and with any heat sources, Stirling engines have found many applications, ranging from
electricity generators and cryocoolers to solar power generators and combined heat and
power systems.
Considering that energy conversion in the engine can only occur through cyclic motions,
we study the bifurcations that lead to the appearance of limit cycles [GC20].
The temperature of the hot piston and the mechanical phase are our bifurcation parameters.
A notion of equivalence for linear complementarity problems with application to
nonsmooth bifurcations
Linear complementarity problems can model many systems of interest to control engineering.
Some examples are mechanical systems with unilateral constraints and electronic circuits with
switching devices.
In [CMF20], we introduce a new notion of equivalence between
linear complementarity problems that sets the basis for the translation of the powerful tools of
smooth bifurcation theory to this class of models. Leveraging this notion of equivalence,
we introduce new tools to analyze, classify, and design nonsmooth bifurcations in linear
complementarity problems and their interconnection.
Optimal control of epidemics
From the perspective of control theory, an epidemic is viewed as a dynamical system with
controlled variables. Its model is an instrument for designing a control action that will
achieve the desired outcome. Depending on the context, different assumptions on the model
and different control objectives can be formulated. In the context of the covid pandemic,
with vaccines scarce or unavailable in many countries, intervention policies based on social
distancing measures were the core containment tool. Considering the dramatic effect that
extended lockdowns have on people and countries economies, a minimum-time control using social
distancing measures and considering hospital capacity restrictions is presented in
[ACMM^{+}21].
The SIR model is arguably the simplest epidemiological model. However, it already
exhibits many of the nonlinear characteristics that are present in more elaborate models.
In [CM21] we make the model more realistic by adding features
such as inaccurate and partial state measurements, and input and measurement delays. Delays
in measurements and policy implementation have proved to be critical in the success or
failure of government strategies. The former correspond to the time taken for the tests to
be carried out, processed, verified, and made available in centralized databases. The latter
correspond to the time it takes the population to adopt restrictions such as quarantine,
social distancing habits, and mask use. A recent approach to the compensation of delays consists
in modifying an observer to predict future states. The stability of the estimation-error dynamics
is addressed from both the perspective of classical frequency-domain quasipolynomial analysis,
and from the perspective of time-domain Lyapunov-Krasowskii analysis.
Fernando Castaños.
Control multivaluado de sistemas hamiltonianos con puerto.
Revista Iberoamericana de Automática e Informática
Industrial, 19:419 – 429, 2022.
[ DOI |
.pdf ]
Emanuel Rocha, Fernando Castaños, and Jaime A. Moreno.
Robust finite-time stabilisation of an arbitrary-order nonholonomic
system in chained form.
Automatica, 135:109956, January 2022.
[ DOI |
.pdf ]
Fernando Castaños and Sabine Mondié.
Observer-based predictor for a susceptible-infectious-recovered model
with delays: An optimal-control case study.
Int. J. Robust Nonlinear Control, 31:5118 – 5133, July 2021.
[ DOI |
.pdf ]
Marco Tulio Angulo, Fernando Castaños, Rodrigo Moreno-Morton, Jorge X.
Velasco-Hernández, and Jaime A. Moreno.
A simple criterion to design optimal non-pharmaceutical interventions
for mitigating epidemic outbreaks.
J. R. Soc. Interface, 18:20200803, 2021.
[ DOI |
.pdf ]
Dmitry Gromov and Fernando Castaños.
Sensitivity Analysis of Limit Cycles in an Alpha Stirling Engine: A Bifurcation-Theory Approach.
SIAM J. Appl. Dyn. Sys., 19:1865 – 1883, August 2020.
[ DOI |
.pdf ]
Félix Miranda, Fernando Castaños, and Bernard Brogliato.
Continuous and discrete-time stability of a robust set-valued nested
controller.
Automatica, 107:406 – 417, September 2019.
[ DOI |
.pdf ]
Nominated by the editor:
This recent Automatica paper caught my eye for its innovative nested signum mapping controller,
its adept handling of nonsmooth analysis and set-valued mappings, and its careful handling of
discretization schemes that reduce chattering. It was a pleasure to read.
Fernando Castaños, Edgar Estrada, Sabine Mondié, and Adrián
Ramírez.
Passivity-based PI control of first-order systems with I/O
communication delays: a frequency domain analysis.
Int. J. Control, 91:2549 – 2562, November 2018.
[ DOI |
.pdf ]
Félix Miranda, Bernard Brogliato, and Fernando Castaños.
Set-valued sliding-mode control of uncertain linear systems:
Continuous and discrete-time analysis.
SIAM J. Control Optim., 56:1756 – 1793, May 2018.
[ DOI |
.pdf ]
Félix Miranda, Bernard Brogliato, and Fernando Castaños.
Multivalued robust tracking control of Lagrange systems: Continuous
and discrete-time algorithms.
IEEE Trans. Autom. Control, 62:4436 – 4450, September 2017.
[ DOI |
.pdf ]
Please see the Errata to “Multivalued robust tracking control of Lagrange
systems: Continuous and discrete-time algorithms”.
IEEE Trans. Autom. Control, 63:2750 – 2750, August 2018.
[ DOI |
Fernando Castaños and Alessio Franci.
Implementing robust neuromodulation in neuromorphic circuits.
Neurocomputing, 233:3 – 13, April 2017.
[ DOI |
.pdf ]
Félix Miranda and Fernando Castaños.
Robust output regulation of strongly passive linear systems with
multivalued maximally monotone controls.
IEEE Trans. Autom. Control, 62:238 – 249, January 2017.
[ DOI |
.pdf ]
Debbie Hernández-Zárate, Fernando Castaños, and Leonid Fridman.
Zero-dynamics design and its application to the stabilization of
implicit systems.
Systems and Control Lett., 98:74 – 78, December 2016.
[ DOI |
.pdf ]
Andrea Aparicio Martínez, Fernando Castaños, and Leonid Fridman.
Output feedback sliding-mode control with unmatched disturbances, an
ISS approach.
Int. J. Robust Nonlinear Control, 26:4056 – 4071, December
2016.
[ DOI |
.pdf ]
Félix Miranda, Fernando Castaños, and Alexander Poznyak.
Min-max piecewise constant optimal control for multi-model linear
systems.
IMA J Math Control Info, 33:1157 – 1176, December 2016.
[ DOI |
.pdf ]
Fernando Castaños and Dmitry Gromov.
Passivity-based control of implicit port-Hamiltonian systems
with holonomic constraints.
Systems and Control Lett., 94:11 – 18, August 2016.
[ DOI |
.pdf ]
Fernando Castaños and Cristian Kunusch.
Ditherless extremum seeking for hydrogen minimization in PEM fuel
cells.
IEEE Trans. Ind. Electron., 62:5218 – 5226, August 2015.
[ DOI |
.pdf ]
Manuel Mera, Fernando Castaños, and Alexander Poznyak.
Quantised and sampled output feedback for nonlinear systems.
Int. J. Control, 87:2475 – 2487, December 2014.
[ DOI |
.pdf ]
Fernando Castaños, Debbie Hernández-Zárate, and Leonid Fridman.
Integral sliding-mode control for linear time-invariant implicit
systems.
Automatica, 50:971 – 975, March 2014.
[ DOI |
.pdf ]
Fernando Castaños, Dmitry Gromov, Vincent Hayward, and Hannah Michalska.
Implicit and explicit representations of continuous-time
port-Hamiltonian systems.
Systems and Control Lett., 62:324 – 330, April 2013.
[ DOI |
.pdf ]
Matteo Rubagotti, Antonio Estrada, Fernando Castaños, Antonella Ferrara,
and Leonid Fridman.
Integral sliding mode control for nonlinear systems with matched and
unmatched perturbations.
IEEE Trans. Autom. Control, 56:2699 – 2704, November 2011.
[ DOI |
.pdf ]
Fernando Castaños and Leonid Fridman.
Dynamic switching surfaces for output sliding mode control: An
H_{∞} approach.
Automatica, 47:1957-1961, September 2011.
[ DOI |
.pdf ]
Fernando Castaños.
Discussion on: “Energy shaping of port-Hamiltonian systems by
using alternate passive input-output pairs”.
European Journal of Control, 16:678 – 679, December 2010.
[ DOI |
.pdf ]
Fernando Castaños, Bayu Jayawardhana, Romeo Ortega, and Eloísa
García-Canseco.
Proportional plus integral control for set-point regulation of a
class of nonlinear RLC circuits.
Circuits Syst. Signal Process., 28:609 – 623, August 2009.
[ DOI |
.pdf ]
Fernando Castaños and Romeo Ortega.
Energy-balancing passivity-based control is equivalent to dissipation
and output invariance.
Systems and Control Lett., 58:553 – 560, August 2009.
[ DOI |
.pdf ]
Fernando Castaños, Romeo Ortega, Arjan J. van der Schaft, and Alessandro
Astolfi.
Asymptotic stabilization via control by interconnection of
port-Hamiltonian systems.
Automatica, 45:1611 – 1618, July 2009.
[ DOI |
.pdf ]
Romeo Ortega, Arjan J. van der Schaft, Fernando Castaños, and Alessandro
Astolfi.
Control by interconnection and standard passivity-based control of
port-Hamiltonian systems.
IEEE Trans. Autom. Control, 53:2527 – 2542, December 2008.
[ DOI |
.pdf ]
Eugenii Shustin, Leonid Fridman, Emilia Fridman, and Fernando Castaños.
Robust semiglobal stabilization of the second order system by relay
feedback with an uncertain variable time delay.
SIAM J. Control Optim., 47:196 – 217, January 2008.
[ DOI |
.pdf ]
Bayu Jayawardhana, Romeo Ortega, Eloísa García-Canseco, and Fernando
Castaños.
Passivity of nonlinear incremental systems: Application to PI
stabilization of nonlinear RLC circuits.
Systems and Control Lett., 56:618 – 622, September 2007.
[ DOI |
.pdf ]
Fernando Castaños and Leonid Fridman.
Analysis and design of integral sliding manifolds for systems with
unmatched perturbations.
IEEE Trans. Autom. Control, 51:853 – 858, May 2006.
[ DOI |
.pdf ]
Yuri Orlov, Leonid Fridman, and Fernando Castaños.
Discussion on: “dynamic sliding mode control for a class of systems
with mismatched uncertainty”.
European Journal of Control, pages 11-18, 2005.
[ DOI |
.pdf ]
Félix Miranda, Fernando Castaños, and Alessio Franci.
Equivalence of Linear Complementarity Problems: Theory and Application to Nonsmooth Bifurcations.
arXiv:2108.06917 [eess.SY], 2021.
[ .pdf ]
Debbie Hernández, Fernando Castaños, and Leonid Fridman.
Pole-placement in higher-order sliding-mode control.
arXiv:1309.3317 [math.OC], 2013.
[ .pdf ]
Ismael Castillo, Fernando Castaños, and Leonid Fridman.
Sliding surface design for higher-order sliding modes.
In Leonid Fridman, Jean-Pierre Barbot, and Franck Plestan, editors,
Recent Trends in Sliding Mode Control, chapter 1.2, pages 29 – 57. The
Institution of Engineering and Technology, Herts, United Kingdom, 2016.
[ DOI ]
Fernando Castaños, Jian-Xin Xu, and Leonid Fridman.
Integral sliding modes for systems with matched and unmatched
uncertainties.
In Christopher Edwards, Enric Fossas Colet, and Leonid Fridman,
editors, Advances in Variable Structure and Sliding Mode Control,
chapter 11, pages 227 – 246. Springer-Verlag, Berlin, 2006.
Bryan Rojas-Ricca, Fernando Castaños, and Sabine Mondié.
A predictor tuning by root multiplicity-induced dominance for
position control of a quadrotor.
In Congreso Nacional de Control Automático, pages 178 – 183,
Tuxtla Gutiérrez, Mexico, October 2022.
[ .pdf ]
Bryan Rojas-Ricca, Fernando Castaños, and Sabine Mondié.
Multiplicity-induced dominance in stabilization of state predictors
for time-delay systems.
In Proc. IFAC Workshop on Time Delay Systems, pages 1 – 6,
Montreal, Canada, September 2022.
[ .pdf ]
Fernando Castaños and Dmitry Gromov.
Limit cycles in locally Hamiltonian systems with dissipation.
In Proc. IFAC Workshop on Lagrangian and Hamiltonian Methods for
Nonlinear Control, pages 201 – 206, Berlin, Germany, November 2021.
[ .pdf ]
Fernando Castaños, Félix Miranda, and Alessio Franci.
A notion of equivalence for linear complementarity problems with
application to the design of non-smooth bifurcations.
In Proc. IFAC World Congress, pages ID – 1340, Berlin, July
2020.
[ .pdf ]
Gian Carlo Gómez-Cortés, Fernando Castaños, and Jorge Dávila.
Sliding motions on SO(3), sliding subgroups.
In Proc. Conference on Decision and Control, pages 6954 –
6958, Nice, France, December 2019.
[ .pdf ]
Oscar B. Cieza, Fernando Castaños, and Johann Regger.
Implicit IDA-PBC for underactuated mechanical systems: An
LMI-based approach.
In Proc. Conference on Decision and Control, pages 7770 –
7775, Nice, France, December 2019.
[ .pdf ]
Gian Carlo Gómez-Cortés, Fernando Castaños, and Jorge Dávila.
Control en la esfera S^{2} usando modos deslizantes.
In Congreso Nacional de Control Automático, pages 778 – 784,
Puebla, Mexico, October 2019.
[ .pdf ]
Pedro Flores-Palmeros, Pedro Castillo, and Fernando Castaños.
Backstepping-based controller for flight formation.
In International Conference on Unmanned Aircraft Systems, pages
254 – 260, Atlanta, GA, June 2019.
[ .pdf ]
Dmitry Gromov, Fernando Castaños, and Alexander L. Fradkov.
Projected dynamics of constrained Hamiltonian systems.
In Proc. European Control Conference, pages 1277 – 1281,
Limassol, Cyprus, June 2018.
[ .pdf ]
Emanuel Rocha, Jaime A. Moreno, and Fernando Castaños.
Homogeneous generalisation of the Lur'e problem and the circle
criterion.
In Proc. IFAC Conf. on Modelling, Identification and Control of
Nonlinear Systems, pages 514 – 519, Guadalajara, Mexico, June 2018.
[ .pdf ]
Dmitry Gromov and Fernando Castaños.
Control of driftless systems using piecewise constant inputs.
In Control Systems (SICE ISCS), 2018 International Symposium
on, pages 226 – 231, Tokyo, Japan, March 2018.
[ .pdf ]
Emanuel Rocha, Jaime A. Moreno, and Fernando Castaños.
Generalización homogénea del problema de Lur'e y del criterio del
círculo.
In Congreso Anual de la AMCA, pages 96 – 101, Monterrey,
Mexico, October 2017.
[ .pdf ]
Dmitry Gromov and Fernando Castaños.
The geometric structure of interconnected thermo-mechanical systems.
In Proc. IFAC World Congress, pages 584 – 589, Toulouse,
France, July 2017.
[ .pdf ]
Félix Miranda, Fernando Castaños, and Bernard Brogliato.
A set-valued nested sliding-mode controller.
In Proc. IFAC World Congress, pages 3026 – 3031, Toulouse,
France, July 2017.
[ .pdf ]
Félix Miranda, Bernard Brogliato, and Fernando Castaños.
Set-valued discrete-time sliding-mode control of uncertain linear
systems.
In Proc. IFAC World Congress, pages 10017 – 10022, Toulouse,
France, July 2017.
[ .pdf ]
Félix Miranda and Fernando Castaños.
Robust output regulation of linear passive systems using maximally
monotone controls.
In Proc. Conference on Decision and Control, pages 6897 –
6902, Osaka, Japan, December 2015.
[ .pdf ]
Fernando Castaños and Alessio Franci.
The transition between tonic spiking and bursting in a six-transistor
neuromorphic device.
In Proc. Int. Conf. on Electrical Eng., Computing Science and
Automatic Control, pages 1 – 6, Mexico City, Mexico, December 2015.
[ .pdf ]
Andrea Aparicio Martínez, Fernando Castaños, and Leonid Fridman.
ISS properties of sliding-mode controllers for systems with matched
and unmatched disturbances.
In Proc. European Control Conference, pages 2870-2875, Linz,
Austria, July 2015.
[ .pdf ]
Fernando Castaños and Dmitry Gromov.
Interconnection and damping assignment for implicit
port-Hamiltonian systems.
In Proc. IFAC Conf. on Modelling, Identification and Control of
Nonlinear Systems, pages 1016 – 1021, Saint Petersburg, Russia, June 2015.
[ .pdf ]
Andrea Aparicio Martínez, Fernando Castaños, and Leonid Fridman.
ISS-Lyapunov functions for output feedback sliding modes.
In Proc. Conference on Decision and Control, pages 5536 –
5541, Los Angeles, California, USA, December 2014.
[ .pdf ]
Debbie Hernández-Zárate, Fernando Castaños, and Leonid Fridman.
Pole-placement in higher-order sliding-mode control.
In Proc. IFAC World Congress, pages 1386 – 1391, Cape Town,
South Africa, August 2014.
[ .pdf ]
Félix Miranda and Fernando Castaños.
Robust output regulation of variable structure systems with
multivalued controls.
In Proc. Variable Structure Systems Workshop, Nantes, Francia,
June 2014.
[ .pdf ]
Andrea Aparicio Martínez, Fernando Castaños, and Leonid Fridman.
Dynamic surface for output feedback sliding modes, the case of
relative degree two.
In Proc. Conference on Decision and Control, pages 3578 –
3583, Florence, Italy, December 2013.
[ .pdf ]
Edgar Estrada, Fernando Castaños, and Sabine Mondié.
σ-estabilidad de sistemas de control basados en pasividad con
retardos en la comunicación.
In Congreso Anual de la AMCA, pages 129 – 134, Ensenada,
Mexico, October 2013.
[ .pdf ]
Andrea Aparicio Martínez and Fernando Castaños.
Control por modos deslizantes por retroalimentación de salida con
grado relativo dos.
In Congreso Anual de la AMCA, pages 544 – 549, Ensenada,
Mexico, October 2013.
[ .pdf ]
Cristian Kunusch and Fernando Castaños.
On the implementation of an adaptive extremum seeking algorithm for
hydrogen minimization in PEM fuel cell based systems.
In Proc. European Control Conference, pages 2501 – 2506,
Zürich, Switzerland, July 2013.
[ .pdf ]
Cristian Kunusch and Fernando Castaños.
Extremum seeking algorithms for minimal hydrogen consumption in PEM
fuel cells.
In Proc. of the American Control Conference, pages 1146 –
1151, Washington, DC, USA, June 2013.
[ .pdf ]
Fernando Castaños, Debbie Hernández-Zárate, and Leonid Fridman.
Integral sliding-mode control for linear time-invariant implicit
descriptions.
In Proc. Conference on Decision and Control, pages 6442 –
6447, Maui, Hawaii, December 2012.
[ .pdf ]
Matteo Rubagotti, Antonio Estrada, Fernando Castaños, Antonella Ferrara,
and Leonid Fridman.
Optimal disturbance rejection by integral sliding mode control for
systems in regular form.
In Proc. of the Variable Structure Systems Workshop, pages 78
- 82, Mexico City, Mexico, June 2010.
[ .pdf ]
Fernando Castaños and Romeo Ortega.
Energy-balancing passivity-based control is equivalent to dissipation
and output invariance.
In Proc. European Control Conference, page WeC2.4, Budapest,
Hungary, August 2009.
[ .pdf ]
Eugenii Shustin, Leonid Fridman, Emilia Shustin, and Fernando Castaños.
Robust semiglobal stabilization of the second order system by relay
feedback with an uncertain variable time delay.
In Proc. Conference on Decision and Control, pages 2716 –
2721, Cancún, México, December 2008.
[ .pdf ]
Fernando Castaños, Romeo Ortega, Arjan J. van der Schaft, and Alessandro
Astolfi.
Asymptotic stabilization via control by interconnection of
port-hamiltonian systems.
In Congreso Latinoamericano de Control Automático,
Mérida, Venezuela, November 2008.
[ .pdf ]
Fernando Castaños, Bayu Jayawardhana, Romeo Ortega, and Eloísa
García-Canseco.
A class of nonlinear RLC circuits globally stabilizable by
proportional plus integral controllers.
In Proc. of the IFAC World Congress, pages 6202 – 6207, Seoul,
Korea, June 2008.
[ .pdf ]
Romeo Ortega, Arjan J. van der Schaft, Fernando Castaños, and Alessandro
Astolfi.
Control by (state-modulated) interconnection of port-Hamiltonian
systems.
In Proc. IFAC Symposium on Nonlinear Control Systems, pages 47
- 54, Pretoria, South Africa, August 2007.
[ .pdf ]
Bayu Jayawardhana, Romeo Ortega, Eloísa García-Canseco, and Fernando
Castaños.
Passivity of nonlinear incremental systems: Application to PI
stabilization of nonlinear RLC circuits.
In Proc. Conference on Decision and Control, page ThIP2.17, San
Diego, December 2006.
[ .pdf ]
Fernando Castaños and Leonid Fridman.
Design of integral sliding manifolds for multi-model uncertain
systems via LMI.
In Proc. of the Variable Structure Systems Workshop, pages
63-67, Alghero, Italy, June 2006.
[ .pdf ]
Fernando Castaños and Leonid Fridman.
Robust design criteria for integral sliding surfaces.
In Proc. Conference on Decision and Control, and European
Control Conference, pages 1976-1981, Seville, Spain, December 2005.
[ .pdf ]
Fernando Castaños and Leonid Fridman.
Integral sliding surface design using an H_{∞}
criterion for decentralized control.
In Proc. of the IFAC World Congress, pages Th-A09-T0/2,
Prague, July 2005.
[ .pdf ]
Fernando Castaños and Leonid Fridman.
Measurement sliding mode-H_{∞} control with
application to decentralized systems.
In Proc. of the Variable Structure Systems Workshop, Vilanova i
la Geltrú, Spain, September 2004.
[ .pdf ]
Leonid Fridman, Fernando Castaños, N. M'Sirdi, and Khraef.
Decomposition and robustness properties of integral sliding mode
controllers.
In Proc. of the Variable Structure Systems Workshop, Vilanova i
la Geltrú, Spain, September 2004.
[ .pdf ]
Fernando Castaños and Leonid Fridman.
Control descentralizado por modos deslizantes.
In Congreso Anual de la AMCA, ISBN: 970-32-2137-8, pages
253-258, México, D.F., 2004.
[ .pdf ]
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