%0 Conference Paper
%B Proc. 20th Mediterranean Conference on Control & Automation (MED)
%D 2012
%T Discrete Fuzzy Polynomial Observers
%A J.L. Pitarch
%A A. Sala
%B Proc. 20th Mediterranean Conference on Control & Automation (MED)
%I IEEE Press
%C Barcelona, Spain
%P 819–823
%@ 978-1-4673-2531-8
%G eng
%0 Journal Article
%J Journal of Process Control
%D 2012
%T Dynamic estimations of metabolic fluxes with constraint-based models and possibility theory
%A Llaneras, Francisco
%A A. Sala
%A J Picó
%B Journal of Process Control
%V 22
%G eng
%U http://www.sciencedirect.com/science/article/pii/S0959152412002181#
%& 1946-1955
%R http://dx.doi.org/10.1016/j.jprocont.2012.09.001
%0 Journal Article
%J Revista Iberoamericana de Automática e Informática Industrial RIAI
%D 2012
%T Estimación del dominio de atracción de sistemas no lineales mediante modelos borrosos polinomiales
%A J.L. Pitarch
%A A. Sala
%E Ariño,C.
%E F. Bedate
%K conservatism
%B Revista Iberoamericana de Automática e Informática Industrial RIAI
%V 9
%P 152 - 161
%G eng
%U http://www.sciencedirect.com/science/article/pii/S1697791212000088
%R 10.1016/j.riai.2012.02.007
%0 Journal Article
%J Rev. Iberoamericana de Automatica e Informatica Industrial
%D 2012
%T Estimación Del Dominio De Atracción De Sistemas No Lineales Mediante Modelos Borrosos Polinomiales
%A J.L. Pitarch
%A A. Sala
%A Arino, C.
%A Bedate, F.
%X Many approaches in fuzzy systems literature express LMI conditions for a Takagi-Sugeno model and finish the problem once those conditions are feasible. However, studying the obtained region of attraction and its relationship with the original nonlinear problem is forgotten. This paper proposes to obtain a predefined-shape zone, as large as possible, belonging to the local domain of attraction of the origin of a nonlinear system. In order to do this, local fuzzy polynomial models are used whose analysis can be carried out by convex optimization (sum of squares). Moreover membership information is used in order to do iterations with the fuzzy modeling region, maximizing the size of the proven domain of attraction, which reduces conservatism over existing results.
%B Rev. Iberoamericana de Automatica e Informatica Industrial
%I Editorial Univ. Polit. Valencia
%V 9
%P 152–161
%G eng
%0 Journal Article
%J Math. Probl. Eng.
%D 2012
%T Linear Matrix Inequalities In Multirate Control Over Networks
%A Cuenca, A.
%A Piza, R.
%A Salt, J.
%A A. Sala
%X This paper faces two of the main drawbacks in networked control systems: bandwidth constraints and timevarying delays. The bandwidth limitations are solved by using multirate control techniques. The resultant multirate controller must ensure closed-loop stability in the presence of time-varying delays. Some stability conditions and a state feedback controller design are formulated in terms of linear matrix inequalities. The theoretical proposal is validated in two different experimental environments: a crane-based test-bed over Ethernet, and a maglev based platform over Profibus.
%B Math. Probl. Eng.
%I Hindawi
%V 1
%P 1–22
%G eng
%0 Conference Paper
%B IEEE World Congress on Computational Intelligence (Fuzz-IEEE)
%D 2012
%T New Controllers And New Designs For Continuous-Time Takagi-Sugeno Models
%A Jaadari, A.
%A Guerra, T.
%A Bernal, M.
%A A. Sala
%A Guelton, K.
%B IEEE World Congress on Computational Intelligence (Fuzz-IEEE)
%C Brisbane, Australia
%P 1–7
%G eng
%0 Journal Article
%J Robotics And Autonomous Systems
%D 2012
%T A Path Conditioning Method With Trap Avoidance
%A Gracia, L.I.
%A A. Sala
%A Garelli, F.
%X This work presents a sliding-mode method for robotic path conditioning. The proposal includes a trap avoidance algorithm in order to escape from trap situations, which are analogous to local minima in potential field-based approaches. The sliding-mode algorithm activates when the desired path is about to violate the robot workspace constraints, modifying it as much as necessary in order to fulfill all the constraints and reaching their limit surface at low speed. The proposed path conditioning algorithm can be used on-line, since it does not require a priori knowledge of the desired path, and improves the conventional conservative potential field-based approach in the sense that it fully exploits the robot workspace. The proposed approach can be easily added as an auxiliary supervisory loop to conventional robotic planning algorithms and its implementation is very easy in a few program lines of a microprocessor. The proposed path conditioning is compared through simulation with the conventional potential field-based approach in order to show the benefits of the method. Moreover, the effectiveness of the proposed trap avoidance algorithm is evaluated by simulation for various trap situations.
%B Robotics And Autonomous Systems
%I Elsevier North-Holland
%V 60
%P 862–873
%G eng
%0 Journal Article
%J Automatica
%D 2012
%T Predictor-Based Stabilization Of Discrete Time-Varying Input-Delay Systems
%A Gonzalez, A.
%A A. Sala
%A Albertos, P.
%X This paper adapts some literature results on stabilizing discrete time-varying input delay systems to the case of having a predictor-based controller. The objective of the paper is showing that the incorporation of predictors to the referred results is relatively simple and, by means of such predictors, robustness against delay mismatch in the input channel may be improved. In this way, larger delay variation margins are proved with predictors when compared to standard memoryless state feedback, as intuitively expected, due to the extra past information available.
%B Automatica
%I Elsevier
%V 48
%P 454–457
%G eng
%0 Conference Paper
%B Semana del Control Automatico
%D 2012
%T A Sliding-Mode Path Conditioning Algorithm To Fulfill End-Effector Constraints In Robotic Systems
%A Garelli, F.
%A Gracia, L.
%A A. Sala
%B Semana del Control Automatico
%C Buenos Aires, Argentina
%P 1–2
%G eng
%0 Conference Paper
%B Proc. of 1st Conference on Embedded Systems, Computational Intelligence and Telematics in Control (CESCIT)
%D 2012
%T Spherical Domain Of Attraction Estimation For Nonlinear Systems
%A J.L. Pitarch
%A A. Sala
%A Arino, C.V.
%X This work proposes an algorithm to obtain a predefined-shape zone as large as possible, belonging to the local domain of attraction of a nonlinear system. In order to do it, fuzzy polynomial models will be used which analysis can be done by convex optimization (sum of squares). Most fuzzy control papers check LMI or SOS stability conditions for Takagi-Sugeno fuzzy models and, if feasibility is reached, forget to study the obtained region and its relationship with the original nonlinear problem. Having into account the shape of the membership functions in a particular region of interest, less conservative stability and stabilization conditions can be easily set up for doing iterations with the fuzzy modelling region in order to maximize the proved basin of attraction.
%B Proc. of 1st Conference on Embedded Systems, Computational Intelligence and Telematics in Control (CESCIT)
%I IFAC/Elsevier
%C Wurzburg, Germany
%P 108–114
%@ 978-3-902661-97-5
%G eng
%0 Journal Article
%J Robotics and Autonomous Systems
%D 2012
%T A supervisory loop approach to fulfill workspace constraints in redundant robots
%A Gracia,Luis
%A A. Sala
%A F Garelli
%K Collision avoidance
%K Redundancy resolution
%K Sliding mode
%X An approach based on geometric invariance and sliding mode ideas is proposed for redundancy resolution in robotic systems to fulfill configuration and workspace constraints caused by robot mechanical limits, collision avoidance, industrial security, etc. Some interesting features of the proposal are that: (1) it can be interpreted as a limit case of the classical potential field-based approach for collision avoidance which requires using variable structure control concepts, (2) it allows reaching the limit surface of the constraints smoothly, depending on a free design parameter, and (3) it can be easily added as a supervisory block to pre-existing redundancy resolution schemes. The algorithm is evaluated in simulation on a 6R planar robot and on the freely accessible 6R robot model PUMA-560, for which the main features of the method are illustrated.
%B Robotics and Autonomous Systems
%V 60
%P 1 - 15
%8 2012/01//
%@ 0921-8890
%G eng
%U http://www.sciencedirect.com/science/article/pii/S0921889011001308
%N 1
%0 Journal Article
%J Robotics And Autonomous Systems
%D 2012
%T A Supervisory Loop Approach To Fulfill Workspace Constraints In Redundant Robots
%A Gracia, L.
%A A. Sala
%A Garelli, F.
%X An approach based on geometric invariance and sliding mode ideas is proposed for redundancy resolution in robotic systems to fulfill configuration and workspace constraints caused by robot mechanical limits, collision avoidance, industrial security, etc. Some interesting features of the proposal are that: (1) it can be interpreted as a limit case of the classical potential field-based approach for collision avoidance which requires using variable structure control concepts, (2) it allows reaching the limit surface of the constraints smoothly, depending on a free design parameter, and (3) it can be easily added as a supervisory block to pre-existing redundancy resolution schemes. The algorithm is evaluated in simulation on a 6R planar robot and on the freely accessible 6R robot model PUMA-560, for which the main features of the method are illustrated.
%B Robotics And Autonomous Systems
%I Elsevier North-Holland
%V 60
%P 1–15
%G eng
%0 Journal Article
%J Industrial Informatics, IEEE Transactions onIndustrial Informatics, IEEE Transactions on
%D 2011
%T A Delay-Dependent Dual-Rate PID Controller Over an Ethernet Network
%A Cuenca,A.
%A Salt,J.
%A A. Sala
%A Piza,R.
%K delay dependent dual rate PID controller
%K delays
%K duality (mathematics)
%K Ethernet network
%K event based control
%K gain scheduling
%K linear matrix inequalities
%K load condition
%K local area networks
%K networked control systems
%K probabilistic linear matrix inequality
%K remote controller
%K stability
%K stability analysis
%K synchronisation
%K three-term control
%K time varying delay
%K time-varying systems
%K TrueTime simulation
%X In this paper, a methodology to design controllers able to cope with different load conditions on an Ethernet network is introduced. Load conditions induce time-varying delays between measurements and control. To face these variations an interpolated, delay-dependent gain scheduling law is used. The lack of synchronization is solved by adopting an event-based control approach. The dual-rate control action computation is carried out at a remote controller, whereas control actions and measurements are taken out locally at the controlled process site. Stability is proved in terms of probabilistic linear matrix inequalities. TrueTime simulations in an Ethernet case show the benefit of the proposal, which is later validated on an experimental test-bed Ethernet environment.
%B Industrial Informatics, IEEE Transactions onIndustrial Informatics, IEEE Transactions on
%V 7
%P 18 - 29
%8 2011///
%@ 1551-3203
%G eng
%N 1
%0 Journal Article
%J Applied Thermal Engineering
%D 2011
%T Efficiency improvement of a ground coupled heat pump system from energy management
%A Pardo,N.
%A Montero,Á.
%A A. Sala
%A Martos,J.
%A Urchueguía,J.F.
%K Energy efficiency
%K Ground coupled heat pump
%K Numerical simulation
%B Applied Thermal Engineering
%V 31
%P 391 - 398
%8 2011/02//
%@ 1359-4311
%G eng
%U http://www.sciencedirect.com/science/article/pii/S1359431110004035
%N 2–3
%0 Journal Article
%J Control Systems Technology, IEEE Transactions onControl Systems Technology, IEEE Transactions on
%D 2011
%T A Transfer-Function Approach to Dual-Rate Controller Design for Unstable and Non-Minimum-Phase Plants
%A Salt,J.
%A A. Sala
%A Albertos,P.
%K algebraic design
%K control system synthesis
%K controller stability
%K Diophantine equations
%K dual-rate controller design
%K dual-rate regulators
%K internal stability
%K linear systems
%K magnetic levitation
%K magnetic levitation setup
%K multivariable control systems
%K nonminimum-phase plants
%K robots
%K single-rate systems
%K stability
%K transfer function approach
%K transfer functions
%K Youla parametrization
%X An algebraic design via Diophantine equations of dual-rate regulators for linear unstable and non-minimum-phase plants, generalizing the well-known constraints for the reference model in single-rate systems, is presented in this brief. This brief improves previous results achieving internal stability for this kind of plants, by means of adapting the Youla parametrization of all stabilizing controllers to the dual-rate case. A simulation example on a robotic model, as well as an experimental magnetic levitation setup, are presented.
%B Control Systems Technology, IEEE Transactions onControl Systems Technology, IEEE Transactions on
%V 19
%P 1186 - 1194
%8 2011///
%@ 1063-6536
%G eng
%N 5
%0 Journal Article
%J IEEE Transactions on Industrial Electronics
%D 2010
%T Detection and Diagnosis of Incipient Faults in Heavy-Duty Diesel Engines
%A Morgan,Ian
%A Liu,Honghai
%A Tormos,Bernardo
%A A. Sala
%B IEEE Transactions on Industrial Electronics
%V 57
%P 3522 - 3532
%8 2010/10//
%@ 0278-0046, 1557-9948
%G eng
%U http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=5371850
%N 10
%0 Journal Article
%J Engineering Applications of Artificial Intelligence
%D 2010
%T Guaranteed cost control analysis and iterative design for constrained Takagi–Sugeno systems
%A Ariño,C.
%A Pérez,Emilio
%A A. Sala
%B Engineering Applications of Artificial Intelligence
%V 23
%P 1420 - 1427
%8 2010/12//
%@ 09521976
%G eng
%U http://linkinghub.elsevier.com/retrieve/pii/S0952197610000795
%N 8
%0 Book
%D 2010
%T Possibilistic Estimation of Metabolic Fluxes During a Batch Process Accounting for Extracellular Dynamics
%A Llaneras, Francisco
%A A. Sala
%A J Picó
%V 11
%G eng
%0 Journal Article
%J Annual Reviews in Control
%D 2009
%T On the conservativeness of fuzzy and fuzzy-polynomial control of nonlinear systems
%A A. Sala
%B Annual Reviews in Control
%V 33
%P 48 - 58
%8 2009/04//
%@ 13675788
%G eng
%U http://linkinghub.elsevier.com/retrieve/pii/S1367578809000042
%N 1
%0 Journal Article
%J IEEE Transactions on Fuzzy Systems
%D 2009
%T Polynomial Fuzzy Models for Nonlinear Control: A Taylor Series Approach
%A A. Sala
%A Ariño,C.
%B IEEE Transactions on Fuzzy Systems
%V 17
%P 1284 - 1295
%8 2009/12//
%@ 1063-6706, 1941-0034
%G eng
%U http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=5191124
%N 6
%0 Journal Article
%J BMC Systems Biology
%D 2009
%T A possibilistic framework for constraint-based metabolic flux analysis
%A Llaneras, Francisco
%A A. Sala
%A J Picó
%B BMC Systems Biology
%V 3
%G eng
%0 Journal Article
%J Information Sciences
%D 2009
%T A retunable PID multi-rate controller for a networked control system
%A A. Sala
%A Cuenca,Ángel
%A Salt,Julián
%B Information Sciences
%V 179
%P 2390 - 2402
%8 2009/06/27/
%@ 00200255
%G eng
%U http://linkinghub.elsevier.com/retrieve/pii/S002002550900111X
%N 14
%0 Journal Article
%J Automatica
%D 2009
%T Sampled-data gain scheduling of continuous LTV plants
%A McKernan,Adrian
%A A. Sala
%A Ariño,C.
%A Irwin,George W.
%B Automatica
%V 45
%P 2451 - 2453
%8 2009/10//
%@ 00051098
%G eng
%U http://linkinghub.elsevier.com/retrieve/pii/S0005109809003148
%N 10
%0 Journal Article
%J IEEE Transactions on Fuzzy Systems
%D 2009
%T A Triangulation Approach to Asymptotically Exact Conditions for Fuzzy Summations
%A Kruszewski,A.
%A A. Sala
%A Guerra,T.M.
%A Ariño,C.
%B IEEE Transactions on Fuzzy Systems
%V 17
%P 985 - 994
%8 2009/10//
%@ 1063-6706, 1941-0034
%G eng
%U http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=4804764
%N 5
%0 Journal Article
%J Information Sciences
%D 2008
%T Encoding fuzzy possibilistic diagnostics as a constrained optimization problem
%A A. Sala
%B Information Sciences
%V 178
%P 4246 - 4263
%8 2008/11//
%@ 00200255
%G eng
%U http://linkinghub.elsevier.com/retrieve/pii/S0020025508002764
%N 22
%0 Journal Article
%J IEEE Transactions on Systems, Man, and Cybernetics, Part B (Cybernetics)
%D 2008
%T Extensions to “Stability Analysis of Fuzzy Control Systems Subject to Uncertain Grades of Membership”
%A Ariño,C.
%A A. Sala
%B IEEE Transactions on Systems, Man, and Cybernetics, Part B (Cybernetics)
%V 38
%P 558 - 563
%8 2008/04//
%@ 1083-4419
%G eng
%U http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=4429192
%N 2
%0 Journal Article
%J IEEE Transactions on Fuzzy Systems
%D 2008
%T Relaxed Stability and Performance LMI Conditions for Takagi--Sugeno Fuzzy Systems With Polynomial Constraints on Membership Function Shapes
%A A. Sala
%A Ariño,C.
%B IEEE Transactions on Fuzzy Systems
%V 16
%P 1328 - 1336
%8 2008/10//
%@ 1063-6706, 1941-0034
%G eng
%U http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=4534857
%N 5
%0 Journal Article
%J Soft Computing
%D 2007
%T A fuzzy clustering algorithm enhancing local model interpretability
%A Díez, José Luis
%A Navarro, J.L.
%A A. Sala
%B Soft Computing
%V 11
%P 973 - 983
%8 2007/01/06/
%@ 1432-7643, 1433-7479
%G eng
%U http://www.springerlink.com/index/10.1007/s00500-006-0146-7
%N 10
%0 Journal Article
%J IEEE Transactions on Control Systems Technology
%D 2007
%T Improving Performance Under Sampling-Rate Variations via Generalized Hold Functions
%A A. Sala
%B IEEE Transactions on Control Systems Technology
%V 15
%P 794 - 797
%8 2007/07//
%@ 1063-6536
%G eng
%U http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=4252104
%N 4
%0 Journal Article
%J Automatica
%D 2007
%T Integrating virtual reference feedback tuning into a unified closed-loop identification framework
%A A. Sala
%B Automatica
%V 43
%P 178 - 183
%8 2007/01//
%@ 00051098
%G eng
%U http://linkinghub.elsevier.com/retrieve/pii/S0005109806003256
%N 1
%0 Journal Article
%J Fuzzy Systems, IEEE Transactions on
%D 2006
%T Controller Design Under Fuzzy Pole-Placement Specifications: An Interval Arithmetic Approach
%A Jorge Bondia
%A A. Sala
%A J Picó
%A Sainz, M.A
%B Fuzzy Systems, IEEE Transactions on
%V 14
%P 822–836
%G eng