Articles de revista
http://hdl.handle.net/2117/3930
20160926T22:33:57Z

Decoupled DCLink capacitor voltage control of DCAC multilevel multileg converters
http://hdl.handle.net/2117/90151
Decoupled DCLink capacitor voltage control of DCAC multilevel multileg converters
Busquets Monge, Sergio; Griñó Cubero, Robert; Nicolás Apruzzese, Joan; Bordonau Farrerons, José
This paper studies the coupling between the capacitor voltage control loops of diodeclamped (or functionally equivalent) multilevel multileg (multiphase) dcac converters. From a complete model of the plant revealing the coupling, a simple approach consisting in multiplying the vector of control commands by a constant matrix is proposed to decouple the control problem and achieve a better controller performance. Simulation and experimental results are presented to prove the superior performance of the proposed decoupled control.
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20160922T16:42:18Z
Busquets Monge, Sergio
Griñó Cubero, Robert
Nicolás Apruzzese, Joan
Bordonau Farrerons, José
This paper studies the coupling between the capacitor voltage control loops of diodeclamped (or functionally equivalent) multilevel multileg (multiphase) dcac converters. From a complete model of the plant revealing the coupling, a simple approach consisting in multiplying the vector of control commands by a constant matrix is proposed to decouple the control problem and achieve a better controller performance. Simulation and experimental results are presented to prove the superior performance of the proposed decoupled control.

Fault tolerant control of a proton exchange membrane fuel cell using TakagiSugeno virtual actuators
http://hdl.handle.net/2117/90060
Fault tolerant control of a proton exchange membrane fuel cell using TakagiSugeno virtual actuators
Rotondo, Damiano; Nejjari AkhiElarab, Fatiha; Puig Cayuela, Vicenç
In this paper, a fault tolerant control (FTC) strategy for proton exchange membrane (PEM) fuel cells based on the use of virtual actuators and the Takagi Sugeno (TS) approach is proposed. The overall solution relies on adding a virtual actuator in the control loop to hide the fault from the controller point of view, allowing it to see the same plant as before the fault, such that the stability and some desired performances are preserved. The proposed methodology is based on the use of a reference model, where the resulting nonlinear error model is brought to a TakagiSugeno form using a gridding approach. The TS model is suitable for designing a controller using linear matrix inequalities (LMI)based techniques, such that the resulting closedloop error system is stable with poles placed in some desired region of the complex plane. Simulation results are used to show the effectiveness of the proposed approach.
20160920T08:42:42Z
Rotondo, Damiano
Nejjari AkhiElarab, Fatiha
Puig Cayuela, Vicenç
In this paper, a fault tolerant control (FTC) strategy for proton exchange membrane (PEM) fuel cells based on the use of virtual actuators and the Takagi Sugeno (TS) approach is proposed. The overall solution relies on adding a virtual actuator in the control loop to hide the fault from the controller point of view, allowing it to see the same plant as before the fault, such that the stability and some desired performances are preserved. The proposed methodology is based on the use of a reference model, where the resulting nonlinear error model is brought to a TakagiSugeno form using a gridding approach. The TS model is suitable for designing a controller using linear matrix inequalities (LMI)based techniques, such that the resulting closedloop error system is stable with poles placed in some desired region of the complex plane. Simulation results are used to show the effectiveness of the proposed approach.

Dynamic modeling and controllability analysis of an ethanol reformer for fuel cell application
http://hdl.handle.net/2117/89384
Dynamic modeling and controllability analysis of an ethanol reformer for fuel cell application
García, Vanesa Mariel; Lopez Null, Eduardo; Serra, Maria; Llorca Piqué, Jordi; Riera Colomer, Jordi
This work presents a controllability analysis of a low temperature ethanol reformer based on a cobalt catalyst for fuel cell application. The study is based on a nonlinear dynamic model of a reformer which operates in three separate stages: ethanol dehydrogenation to acetaldehyde and hydrogen, acetaldehyde steam reforming, and water gas shift reaction. The controllability anal
ysis is focused on the rapid dynamics due to mass balances and is based on a linear
ization of the complex nonlinear model of the reformer. RGA, CN and MRI analysis tools are applied to the linear model suggesting that a good performance can be
obtained with decentralized control for frequencies up to 0.1 rad/s.
20160824T12:41:35Z
García, Vanesa Mariel
Lopez Null, Eduardo
Serra, Maria
Llorca Piqué, Jordi
Riera Colomer, Jordi
This work presents a controllability analysis of a low temperature ethanol reformer based on a cobalt catalyst for fuel cell application. The study is based on a nonlinear dynamic model of a reformer which operates in three separate stages: ethanol dehydrogenation to acetaldehyde and hydrogen, acetaldehyde steam reforming, and water gas shift reaction. The controllability anal
ysis is focused on the rapid dynamics due to mass balances and is based on a linear
ization of the complex nonlinear model of the reformer. RGA, CN and MRI analysis tools are applied to the linear model suggesting that a good performance can be
obtained with decentralized control for frequencies up to 0.1 rad/s.

Exact interval propagation for the efficient solution of position analysis problems on planar linkages
http://hdl.handle.net/2117/89383
Exact interval propagation for the efficient solution of position analysis problems on planar linkages
Celaya Llover, Enric; Creemers, Tom Lambert; Ros Giralt, Lluís
This paper presents an interval propagation algorithm for variables in planar singleloop linkages. Given intervals of allowed values for all variables, the algorithm provides, for every variable, the whole set of values, with out overestimation, for which the linkage can actually be assembled. We show further how this algorithm can be integrated in a branchandprune search scheme, in order to solve the position analysis of general planar multiloop linkages. Experimental results are included, comparing the method’s perfor mance with that of previous techniques given for the same task.
20160824T10:56:12Z
Celaya Llover, Enric
Creemers, Tom Lambert
Ros Giralt, Lluís
This paper presents an interval propagation algorithm for variables in planar singleloop linkages. Given intervals of allowed values for all variables, the algorithm provides, for every variable, the whole set of values, with out overestimation, for which the linkage can actually be assembled. We show further how this algorithm can be integrated in a branchandprune search scheme, in order to solve the position analysis of general planar multiloop linkages. Experimental results are included, comparing the method’s perfor mance with that of previous techniques given for the same task.

Stock management in hospital pharmacy using chanceconstrained model predictive control
http://hdl.handle.net/2117/89382
Stock management in hospital pharmacy using chanceconstrained model predictive control
Jurado, Isabel; Maestre Torreblanca, José María; Velarde, Pablo; OcampoMartínez, Carlos; Fernandez, Isabel; Isla Tejera, Beatriz; del Prado, José Ramón
One of the most important problems in the pharmacy department of a hospital is stock management. The clinical needs of drugs must be satisfied with limited work labor while minimizing the use of economical resources. The complexity of the problem resides in the random nature of the drug demand and the multiple constraints that must be taken into account in every decision. In this article, chanceconstrained model predictive control is proposed to deal with this problem. The flexibility of model predictive control allows taking into account explicitly the different objectives and constraints involved in the problem while the use of chance constraints provides a tradeoff between conservativeness and efficiency. The solution proposed is assessed to study its implementation in two Spanish hospitals
20160824T10:09:12Z
Jurado, Isabel
Maestre Torreblanca, José María
Velarde, Pablo
OcampoMartínez, Carlos
Fernandez, Isabel
Isla Tejera, Beatriz
del Prado, José Ramón
One of the most important problems in the pharmacy department of a hospital is stock management. The clinical needs of drugs must be satisfied with limited work labor while minimizing the use of economical resources. The complexity of the problem resides in the random nature of the drug demand and the multiple constraints that must be taken into account in every decision. In this article, chanceconstrained model predictive control is proposed to deal with this problem. The flexibility of model predictive control allows taking into account explicitly the different objectives and constraints involved in the problem while the use of chance constraints provides a tradeoff between conservativeness and efficiency. The solution proposed is assessed to study its implementation in two Spanish hospitals

Stochastic model predictive control based on Gaussian processes applied to drinking water networks
http://hdl.handle.net/2117/89276
Stochastic model predictive control based on Gaussian processes applied to drinking water networks
Wang, Ye; OcampoMartínez, Carlos; Puig Cayuela, Vicenç
This study focuses on developing a stochastic model predictive control (MPC) strategy based on Gaussian processes (GPs) for propagating system disturbances in a receding horizon way. Using a probabilistic system representation, the state trajectories considering the influence of disturbances can be obtained through the uncertainty propagation by using GPs. This fact allows obtaining the confidence intervals for state evolutions over the MPC prediction horizon that are included into the MPC objective function and constraints. The feasibility of the proposed MPC strategy considering the incorporated results of disturbance forecasting is also discussed. Simulation results obtained from the application of the proposed approach to the Barcelona drinking water network taking real demand data into account are presented. The comparison with the wellknown certaintyequivalent MPC shows the effectiveness of the proposed stochastic MPC approach.
20160727T13:44:34Z
Wang, Ye
OcampoMartínez, Carlos
Puig Cayuela, Vicenç
This study focuses on developing a stochastic model predictive control (MPC) strategy based on Gaussian processes (GPs) for propagating system disturbances in a receding horizon way. Using a probabilistic system representation, the state trajectories considering the influence of disturbances can be obtained through the uncertainty propagation by using GPs. This fact allows obtaining the confidence intervals for state evolutions over the MPC prediction horizon that are included into the MPC objective function and constraints. The feasibility of the proposed MPC strategy considering the incorporated results of disturbance forecasting is also discussed. Simulation results obtained from the application of the proposed approach to the Barcelona drinking water network taking real demand data into account are presented. The comparison with the wellknown certaintyequivalent MPC shows the effectiveness of the proposed stochastic MPC approach.

Assessment of responsiveness levels during sedationanalgesia by entropy analysis of EEG
http://hdl.handle.net/2117/89087
Assessment of responsiveness levels during sedationanalgesia by entropy analysis of EEG
Valencia, Jose Fernando; Melia, Umberto; Vallverdú Ferrer, Montserrat; Jospin, Mathieu; Jensen, Erik Weber; Porta, Alberto; Gambus, Pedro L.; Caminal Magrans, Pere
The level of sedation in patients undergoing medical procedures is decided to assure unconsciousness and prevent pain. The monitors of depth of anesthesia, based on the analysis of the electroencephalogram (EEG), have been progressively introduced into the daily practice to provide additional information about the state of the patient. However, the quantification of analgesia still remains an open problem. The purpose of this work was to analyze the capability of prediction of nociceptive responses based on refined multiscale entropy (RMSE) and auto mutual information function (AMIF) applied to EEG signals recorded in 378 patients scheduled to undergo ultrasonographic endoscopy under sedationanalgesia. Two observed categorical responses after the application of painful stimulation were analyzed: the evaluation of the Ramsay Sedation Scale (RSS) after nail bed compression and the presence of gag reflex (GAG) during endoscopy tube insertion. Also, BIS, heart rate (HR), predicted concentrations of propofol (CeProp) and remifentanil (CeRemi) were annotated with a resolution of 1 second. Results showed that functions based on RMSE, AMIF, HR and CeRemi permitted to predict different stimulation responses during sedation with better than BIS.
20160722T11:57:33Z
Valencia, Jose Fernando
Melia, Umberto
Vallverdú Ferrer, Montserrat
Jospin, Mathieu
Jensen, Erik Weber
Porta, Alberto
Gambus, Pedro L.
Caminal Magrans, Pere
The level of sedation in patients undergoing medical procedures is decided to assure unconsciousness and prevent pain. The monitors of depth of anesthesia, based on the analysis of the electroencephalogram (EEG), have been progressively introduced into the daily practice to provide additional information about the state of the patient. However, the quantification of analgesia still remains an open problem. The purpose of this work was to analyze the capability of prediction of nociceptive responses based on refined multiscale entropy (RMSE) and auto mutual information function (AMIF) applied to EEG signals recorded in 378 patients scheduled to undergo ultrasonographic endoscopy under sedationanalgesia. Two observed categorical responses after the application of painful stimulation were analyzed: the evaluation of the Ramsay Sedation Scale (RSS) after nail bed compression and the presence of gag reflex (GAG) during endoscopy tube insertion. Also, BIS, heart rate (HR), predicted concentrations of propofol (CeProp) and remifentanil (CeRemi) were annotated with a resolution of 1 second. Results showed that functions based on RMSE, AMIF, HR and CeRemi permitted to predict different stimulation responses during sedation with better than BIS.

Planning wrenchfeasible motions for cabledriven hexapods
http://hdl.handle.net/2117/89084
Planning wrenchfeasible motions for cabledriven hexapods
Bohigas Nadal, Oriol; Manubens Ferriol, Montserrat; Ros Giralt, Lluís
Motion paths of cabledriven hexapods must carefully be planned to ensure that the lengths and tensions of all cables remain within acceptable limits, for a given wrench applied to the platform. The cables cannot go slackto keep the control of the robotnor excessively tightto prevent cable breakageeven in the presence of bounded perturbations of the wrench. This paper proposes a pathplanning method that accommodates such constraints simultaneously. Given two configurations of the robot, the method attempts to connect them through a path that, at any point, allows the cables to counteract any wrench lying in a predefined uncertainty region. The configuration space, or Cspace for short, is placed in correspondence with a smooth manifold, which facilitates the definition of a continuation strategy to search this space systematically from one configuration, until the second configuration is found, or path nonexistence is proved by exhaustion of the search. The force Jacobian is full rank everywhere on the Cspace, which implies that the computed paths will naturally avoid crossing the forward singularity locus of the robot. The adjustment of tension limits, moreover, allows to maintain a meaningful clearance relative to such locus. The approach is applicable to compute paths subject to geometric constraints on the platform pose or to synthesize freeflying motions in the full 6D Cspace. Experiments illustrate the performance of the method in a real prototype.
20160722T11:01:38Z
Bohigas Nadal, Oriol
Manubens Ferriol, Montserrat
Ros Giralt, Lluís
Motion paths of cabledriven hexapods must carefully be planned to ensure that the lengths and tensions of all cables remain within acceptable limits, for a given wrench applied to the platform. The cables cannot go slackto keep the control of the robotnor excessively tightto prevent cable breakageeven in the presence of bounded perturbations of the wrench. This paper proposes a pathplanning method that accommodates such constraints simultaneously. Given two configurations of the robot, the method attempts to connect them through a path that, at any point, allows the cables to counteract any wrench lying in a predefined uncertainty region. The configuration space, or Cspace for short, is placed in correspondence with a smooth manifold, which facilitates the definition of a continuation strategy to search this space systematically from one configuration, until the second configuration is found, or path nonexistence is proved by exhaustion of the search. The force Jacobian is full rank everywhere on the Cspace, which implies that the computed paths will naturally avoid crossing the forward singularity locus of the robot. The adjustment of tension limits, moreover, allows to maintain a meaningful clearance relative to such locus. The approach is applicable to compute paths subject to geometric constraints on the platform pose or to synthesize freeflying motions in the full 6D Cspace. Experiments illustrate the performance of the method in a real prototype.

Automated resolution of chromatographic signals by independent component analysisorthogonal signal deconvolution in comprehensive gas chromatography/mass spectrometrybased metabolomics
http://hdl.handle.net/2117/89076
Automated resolution of chromatographic signals by independent component analysisorthogonal signal deconvolution in comprehensive gas chromatography/mass spectrometrybased metabolomics
Domingo Almenara, Xavier; Perera Lluna, Alexandre; Ramirez, Noelia; Brezmes, Jesus
Comprehensive gas chromatographymass spectrometry (GC x GCMS) provides a different perspective in metabolomics profiling of samples. However, algorithms for GCx GCMS data processing are needed in order to automatically process the data and extract the purest information about the compounds appearing in complex biological samples. This study shows the capability of independent component analysisorthogonal signal deconvolution (ICAOSD), an algorithm based on blind source separation and distributed in an R package called osd, to extract the spectra of the compounds appearing in GCx GCMS chromatograms in an automated manner. We studied the performance of ICAOSD by the quantification of 38 metabolites through a set of 20 Jurkat cell samples analyzed by GCx GCMS. The quantification by ICAOSD was compared with a supervised quantification by selective ions, and most of the R2 coefficients of determination were in good agreement (R2>0.90) while up to 24 cases exhibited an excellent linear relation (R2>0.95). We concluded that ICAOSD can be used to resolve coeluted compounds in GC x GCMS. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
20160722T09:36:43Z
Domingo Almenara, Xavier
Perera Lluna, Alexandre
Ramirez, Noelia
Brezmes, Jesus
Comprehensive gas chromatographymass spectrometry (GC x GCMS) provides a different perspective in metabolomics profiling of samples. However, algorithms for GCx GCMS data processing are needed in order to automatically process the data and extract the purest information about the compounds appearing in complex biological samples. This study shows the capability of independent component analysisorthogonal signal deconvolution (ICAOSD), an algorithm based on blind source separation and distributed in an R package called osd, to extract the spectra of the compounds appearing in GCx GCMS chromatograms in an automated manner. We studied the performance of ICAOSD by the quantification of 38 metabolites through a set of 20 Jurkat cell samples analyzed by GCx GCMS. The quantification by ICAOSD was compared with a supervised quantification by selective ions, and most of the R2 coefficients of determination were in good agreement (R2>0.90) while up to 24 cases exhibited an excellent linear relation (R2>0.95). We concluded that ICAOSD can be used to resolve coeluted compounds in GC x GCMS. (C) 2016 Elsevier Ireland Ltd. All rights reserved.

Protocol for regional implementation of collaborative lung function testing
http://hdl.handle.net/2117/89071
Protocol for regional implementation of collaborative lung function testing
Vargas, Claudia Lorena; Burgos Rincón, Felip; Cano, Isaac; Blanco, Isabel; Caminal Magrans, Pere; Escarrabill, Joan; Gallego, Carles; Llauger, Maria Antonia; Miralles, Felip; Solans, Oscar; Vallverdú Ferrer, Montserrat; Velickovski, Filip; Roca Torrent, Josep
20160722T09:13:43Z
Vargas, Claudia Lorena
Burgos Rincón, Felip
Cano, Isaac
Blanco, Isabel
Caminal Magrans, Pere
Escarrabill, Joan
Gallego, Carles
Llauger, Maria Antonia
Miralles, Felip
Solans, Oscar
Vallverdú Ferrer, Montserrat
Velickovski, Filip
Roca Torrent, Josep