Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981615
M. Taktak-Meziou, A. Chemori, J. Ghommam, N. Derbel
This paper presents a prediction-based optimal gain selection in Robust Integral Sign of the Error (RISE) based Neural Network (NN) approach. Previous research has shown that combining a feedforward term with a feedback control element yields an asymptotically stable closed-loop system. The proposed approach adds a prediction-based optimal technique which minimizes a quadratic performance index to calculate an optimal feedback gain. The resulting novel controller, called P-RISE-NN, is applied for a track following problem of a Hard-Disc-Drive servo-system. Simulation studies are used to show the efficiency of the proposed control scheme and its robustness against external disturbances and parametric uncertainties in the system. The authors believe that the proposed control solution combining RISE with a predictive control approach has never been conducted before.
{"title":"A prediction-based optimal gain selection in RISE feedback control for hard disk drive","authors":"M. Taktak-Meziou, A. Chemori, J. Ghommam, N. Derbel","doi":"10.1109/CCA.2014.6981615","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981615","url":null,"abstract":"This paper presents a prediction-based optimal gain selection in Robust Integral Sign of the Error (RISE) based Neural Network (NN) approach. Previous research has shown that combining a feedforward term with a feedback control element yields an asymptotically stable closed-loop system. The proposed approach adds a prediction-based optimal technique which minimizes a quadratic performance index to calculate an optimal feedback gain. The resulting novel controller, called P-RISE-NN, is applied for a track following problem of a Hard-Disc-Drive servo-system. Simulation studies are used to show the efficiency of the proposed control scheme and its robustness against external disturbances and parametric uncertainties in the system. The authors believe that the proposed control solution combining RISE with a predictive control approach has never been conducted before.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124036972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981402
B. J. T. Binder, D. Kufoalor, A. Pavlov, T. Johansen
Electric Submersible Pumps (ESPs) can be installed in oil wells to create artificial lift, in order to increase recovery from the reservoir, and boost the production rate. A Model Predictive Controller (MPC) for an ESP, based on linearized models, is developed and designed using SEPTIC (Statoil's in-house software tool for MPC), and implemented on a Programmable Logic Controller (PLC). Automatic code generators have been utilized to generate an application-specific MPC controller in ANSI C code. Hardware-in-the-loop simulation results show that the control performance of the PLC implementation is comparable to the original SEPTIC controller.
{"title":"Embedded Model Predictive Control for an Electric Submersible Pump on a Programmable Logic Controller","authors":"B. J. T. Binder, D. Kufoalor, A. Pavlov, T. Johansen","doi":"10.1109/CCA.2014.6981402","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981402","url":null,"abstract":"Electric Submersible Pumps (ESPs) can be installed in oil wells to create artificial lift, in order to increase recovery from the reservoir, and boost the production rate. A Model Predictive Controller (MPC) for an ESP, based on linearized models, is developed and designed using SEPTIC (Statoil's in-house software tool for MPC), and implemented on a Programmable Logic Controller (PLC). Automatic code generators have been utilized to generate an application-specific MPC controller in ANSI C code. Hardware-in-the-loop simulation results show that the control performance of the PLC implementation is comparable to the original SEPTIC controller.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129012654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981462
Guillaume Allibert, D. Abeywardena, Moses Bangura, R. Mahony
A key requirement for effective control of quadrotor vehicles is estimation of both attitude and linear velocity. Recent work has demonstrated that it is possible to measure horizontal velocities of a quadrotor vehicle from strap-down ac-celerometers along with a system model. In this paper we extend this to full body-fixed-frame velocity measurement by exploiting recent work in aerodynamic modeling of rotor performance and measurements of mechanical power supplied to the rotor hub. We use these measurements in a combined attitude and velocity nonlinear observer design to jointly estimate attitude and body-fixed-frame linear velocity. Almost global asymptotic stability of the resulting system is demonstrated using Lyapunov analysis of the resulting error system. In the current work, we ignore bias and leave it for future work. The performance of the observer is verified by simulation results.
{"title":"Estimating body-fixed frame velocity and attitude from inertial measurements for a quadrotor vehicle","authors":"Guillaume Allibert, D. Abeywardena, Moses Bangura, R. Mahony","doi":"10.1109/CCA.2014.6981462","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981462","url":null,"abstract":"A key requirement for effective control of quadrotor vehicles is estimation of both attitude and linear velocity. Recent work has demonstrated that it is possible to measure horizontal velocities of a quadrotor vehicle from strap-down ac-celerometers along with a system model. In this paper we extend this to full body-fixed-frame velocity measurement by exploiting recent work in aerodynamic modeling of rotor performance and measurements of mechanical power supplied to the rotor hub. We use these measurements in a combined attitude and velocity nonlinear observer design to jointly estimate attitude and body-fixed-frame linear velocity. Almost global asymptotic stability of the resulting system is demonstrated using Lyapunov analysis of the resulting error system. In the current work, we ignore bias and leave it for future work. The performance of the observer is verified by simulation results.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127963924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981585
A. Rauh, Ole Krägenbring, Lukas Pröhl, H. Aschemann
In previous work, it has been shown that sensitivity-based procedures can be employed effectively for the design of predictive control strategies, for the implementation of state estimators as well as for the offline and online identification of system parameters. These procedures were used, on the one hand, for control of dynamic processes which perform a certain task only once and, on the other hand, also for the control of systems that are operated in a repetitive manner. The latter class of applications is hence closely related to the design of iterative learning control strategies. A common feature of all sensitivity-based approaches implemented so far by the authors is that the control signals are piecewise constant on an equidistant time discretization mesh. However, this assumption may make the computation of differential sensitivities inefficient if long control horizons are taken into account for learning-type controllers of processes with a fast dynamics. Therefore, this assumption is removed in the current paper, both by a control parameterization using polynomial ansatz functions and by a computation of optimal switching points for piecewise constant control signals. The adaptive discretization scheme of the latter approach allows for obeying predefined performance constraints with a minimum memory demand. These procedures are demonstrated by simulations for a prototypical high-speed rack feeder system.
{"title":"Sensitivity-based approaches for an efficient design of learning-type controllers of a flexible high-speed rack feeder system","authors":"A. Rauh, Ole Krägenbring, Lukas Pröhl, H. Aschemann","doi":"10.1109/CCA.2014.6981585","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981585","url":null,"abstract":"In previous work, it has been shown that sensitivity-based procedures can be employed effectively for the design of predictive control strategies, for the implementation of state estimators as well as for the offline and online identification of system parameters. These procedures were used, on the one hand, for control of dynamic processes which perform a certain task only once and, on the other hand, also for the control of systems that are operated in a repetitive manner. The latter class of applications is hence closely related to the design of iterative learning control strategies. A common feature of all sensitivity-based approaches implemented so far by the authors is that the control signals are piecewise constant on an equidistant time discretization mesh. However, this assumption may make the computation of differential sensitivities inefficient if long control horizons are taken into account for learning-type controllers of processes with a fast dynamics. Therefore, this assumption is removed in the current paper, both by a control parameterization using polynomial ansatz functions and by a computation of optimal switching points for piecewise constant control signals. The adaptive discretization scheme of the latter approach allows for obeying predefined performance constraints with a minimum memory demand. These procedures are demonstrated by simulations for a prototypical high-speed rack feeder system.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128569804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981459
O. Gaye, O. Pagès, A. Hajjaji
This communication deals with the robust H∞ stabilization of the semilinear partial differential system using Lyapunov theory. The time derivative of this Lyapunov function can be made strictly negative definite by an appropriate choice of controls. In general, it is difficult to control partial differential systems. In order to simplify the design procedure of control law, a fuzzy partial differential system based on fuzzy interpolation approach is proposed. Based on this distributed model, the distributed robust control design is proposed to attenuate disturbances via solving linear matrix inequalities (LMIs). Finally, numerical results are presented and discussed to illustrate the effectiveness of the proposed approach.
{"title":"Robust control design of semilinear parabolic partial differential systems: A fuzzy approach","authors":"O. Gaye, O. Pagès, A. Hajjaji","doi":"10.1109/CCA.2014.6981459","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981459","url":null,"abstract":"This communication deals with the robust H∞ stabilization of the semilinear partial differential system using Lyapunov theory. The time derivative of this Lyapunov function can be made strictly negative definite by an appropriate choice of controls. In general, it is difficult to control partial differential systems. In order to simplify the design procedure of control law, a fuzzy partial differential system based on fuzzy interpolation approach is proposed. Based on this distributed model, the distributed robust control design is proposed to attenuate disturbances via solving linear matrix inequalities (LMIs). Finally, numerical results are presented and discussed to illustrate the effectiveness of the proposed approach.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125117022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981387
S. Panza, M. Lovera
Helicopter flight control law design including rotor state feedback is considered and an approach based on structured H∞ control, capable of guaranteeing stability and performance robustness, is proposed. The framework also encompasses fault tolerance with respect to failures of the rotor state sensors. Simulation results comparing the proposed approach to results from the literature are presented and discussed.
{"title":"Rotor state feedback in helicopter flight control: Robustness and fault tolerance","authors":"S. Panza, M. Lovera","doi":"10.1109/CCA.2014.6981387","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981387","url":null,"abstract":"Helicopter flight control law design including rotor state feedback is considered and an approach based on structured H∞ control, capable of guaranteeing stability and performance robustness, is proposed. The framework also encompasses fault tolerance with respect to failures of the rotor state sensors. Simulation results comparing the proposed approach to results from the literature are presented and discussed.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"2014 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128017269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981534
D. Caiado, J. M. Lemos, J. M. Igreja
This article addresses the problem of obtaining reduced complexity models of multi-reach water delivery canals that are suitable for robust and linear parameter varying (LPV) control design. In the first stage, by applying a method known from the literature, a finite dimensional rational transfer function of a priori defined order is obtained for each canal reach by linearizing the Saint-Venant equations. Then, by using block diagrams algebra, these different models are combined with linearized gate models in order to obtain the overall canal model. In what concerns the control design objectives, this approach has the advantages of providing a model with prescribed order and to quantify the high frequency uncertainty due to model approximation. A case study with a 3-reach canal is presented, and the resulting model is compared with experimental data.
{"title":"Modeling for control design of a multi-reach water canal","authors":"D. Caiado, J. M. Lemos, J. M. Igreja","doi":"10.1109/CCA.2014.6981534","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981534","url":null,"abstract":"This article addresses the problem of obtaining reduced complexity models of multi-reach water delivery canals that are suitable for robust and linear parameter varying (LPV) control design. In the first stage, by applying a method known from the literature, a finite dimensional rational transfer function of a priori defined order is obtained for each canal reach by linearizing the Saint-Venant equations. Then, by using block diagrams algebra, these different models are combined with linearized gate models in order to obtain the overall canal model. In what concerns the control design objectives, this approach has the advantages of providing a model with prescribed order and to quantify the high frequency uncertainty due to model approximation. A case study with a 3-reach canal is presented, and the resulting model is compared with experimental data.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125726084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981527
S. Wakitani, Toru Yamamoto
Research on database utilization has received much attention in recent years. This paper presents a data-driven proportional-integral-derivative (DD-PID) controller design method that uses a large database. In this method, a large data-set comprising input/output (I/O) data and control parameters is stored in a database in advance, and current control parameters are tuned by using the database in an online manner. The DD-PID controller design method utilizes the fictitious reference iterative tuning (FRIT) approach to learn control parameters in the database in an offline manner by utilizing initial experimental I/O data. This method is called the DD-FRIT method. In the study, the DD-FRIT method was applied to a nonlinear tank system to evaluate its effectiveness. This paper is structured as follows. First, the DD-PID controller design method is presented. Next, the offline learning algorithm that combines the design method with FRIT is explained. Finally, the results of a simulation and experiment are presented to demonstrate the effectiveness of the proposed method. These results showed that control parameters in the database were learned appropriately by the proposed method, and good control results were obtained.
{"title":"Design and application of a data-driven PID controller","authors":"S. Wakitani, Toru Yamamoto","doi":"10.1109/CCA.2014.6981527","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981527","url":null,"abstract":"Research on database utilization has received much attention in recent years. This paper presents a data-driven proportional-integral-derivative (DD-PID) controller design method that uses a large database. In this method, a large data-set comprising input/output (I/O) data and control parameters is stored in a database in advance, and current control parameters are tuned by using the database in an online manner. The DD-PID controller design method utilizes the fictitious reference iterative tuning (FRIT) approach to learn control parameters in the database in an offline manner by utilizing initial experimental I/O data. This method is called the DD-FRIT method. In the study, the DD-FRIT method was applied to a nonlinear tank system to evaluate its effectiveness. This paper is structured as follows. First, the DD-PID controller design method is presented. Next, the offline learning algorithm that combines the design method with FRIT is explained. Finally, the results of a simulation and experiment are presented to demonstrate the effectiveness of the proposed method. These results showed that control parameters in the database were learned appropriately by the proposed method, and good control results were obtained.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"270 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114476473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981332
Andrea Perizzato, M. Farina, L. Piroddi, R. Scattolini, E. Osto
Defective bearings can jeopardize the good functioning of rotating machinery. In this work we employ multivariate statistical techniques to monitor a drive reducer in a hot steel rolling mill, with the aim of detecting incipient defects associated to rolling bearings. Several vibration signals are measured and processed for this purpose, as well as the current absorbed by the motor driving the mill. A normal condition reference model is first constructed and deviations from it are detected by monitoring T2 statistics. Classical bearing defect models are employed to test the fault detection capabilities of the method.
{"title":"Fault detection of bearings in a drive reducer of a hot steel rolling mill","authors":"Andrea Perizzato, M. Farina, L. Piroddi, R. Scattolini, E. Osto","doi":"10.1109/CCA.2014.6981332","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981332","url":null,"abstract":"Defective bearings can jeopardize the good functioning of rotating machinery. In this work we employ multivariate statistical techniques to monitor a drive reducer in a hot steel rolling mill, with the aim of detecting incipient defects associated to rolling bearings. Several vibration signals are measured and processed for this purpose, as well as the current absorbed by the motor driving the mill. A normal condition reference model is first constructed and deviations from it are detected by monitoring T2 statistics. Classical bearing defect models are employed to test the fault detection capabilities of the method.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127789529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2014-12-11DOI: 10.1109/CCA.2014.6981517
P. Odgaard, A. Nejad
Reliability and availability of modern wind turbines are of increasing importance, for two reasons. The first is due to the fact that power grids around in the world depends at a higher and higher degree on wind energy, and the second is the importance of lowering Cost of Energy of the wind turbines. One of the critical components in modern wind turbines is the gearbox. Failures in the gearbox are costly both due to the cost of the gearbox itself, but also due to lost power generation during repair of it. Wind turbine gearboxes are consequently monitored by condition monitoring systems operating in parallel with the control system, and also uses additional sensors measuring different accelerations and noises, etc. In this paper gearbox data from high fidelity gearbox model of a 750 kW wind turbine gearbox, simulated with and without faults are used to shown the potential of frequency based detection schemes applied on measurements normally available in a wind controller system. This paper shows that two given faults in the gearbox can be detected using a frequency based detection approach applied to sensor signals normally available in the wind turbine control system. This means that gearbox condition monitoring/ fault detection could be included in the standard control system, which potentially can remove the cost of the additional condition monitoring system and the additional sensors used in it.
{"title":"Frequency based wind turbine gearbox fault detection applied to a 750 kW wind turbine","authors":"P. Odgaard, A. Nejad","doi":"10.1109/CCA.2014.6981517","DOIUrl":"https://doi.org/10.1109/CCA.2014.6981517","url":null,"abstract":"Reliability and availability of modern wind turbines are of increasing importance, for two reasons. The first is due to the fact that power grids around in the world depends at a higher and higher degree on wind energy, and the second is the importance of lowering Cost of Energy of the wind turbines. One of the critical components in modern wind turbines is the gearbox. Failures in the gearbox are costly both due to the cost of the gearbox itself, but also due to lost power generation during repair of it. Wind turbine gearboxes are consequently monitored by condition monitoring systems operating in parallel with the control system, and also uses additional sensors measuring different accelerations and noises, etc. In this paper gearbox data from high fidelity gearbox model of a 750 kW wind turbine gearbox, simulated with and without faults are used to shown the potential of frequency based detection schemes applied on measurements normally available in a wind controller system. This paper shows that two given faults in the gearbox can be detected using a frequency based detection approach applied to sensor signals normally available in the wind turbine control system. This means that gearbox condition monitoring/ fault detection could be included in the standard control system, which potentially can remove the cost of the additional condition monitoring system and the additional sensors used in it.","PeriodicalId":205599,"journal":{"name":"2014 IEEE Conference on Control Applications (CCA)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127913115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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