Digital system upsets can occur as a result of electrical transients induced by electromagnetic fields. One possible upset is the irrecoverable loss of sensor data due to noisy readings or data changes in the input circuitry. The control system may not perform adequately when faced with such modes of failure. The paper focuses on a technique in which a virtual closed loop is used to overcome these modes of failure. The advantage of using this technique is confirmed by results from a DC motor control system set-up in electromagnetic environments.
{"title":"A virtual closed loop remedy for temporary sensor failures","authors":"J. Suh, G. Bajpai, B. Chang","doi":"10.1109/CCA.1999.801196","DOIUrl":"https://doi.org/10.1109/CCA.1999.801196","url":null,"abstract":"Digital system upsets can occur as a result of electrical transients induced by electromagnetic fields. One possible upset is the irrecoverable loss of sensor data due to noisy readings or data changes in the input circuitry. The control system may not perform adequately when faced with such modes of failure. The paper focuses on a technique in which a virtual closed loop is used to overcome these modes of failure. The advantage of using this technique is confirmed by results from a DC motor control system set-up in electromagnetic environments.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122323447","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}
T.A. Mast, A. Reed, S. Yurkovich, M. Ashby, S. Adibhatla
Describes the methodology for usage of Bayesian belief networks (BBNs) in fault detection for aircraft gas turbine engines. First, the basic theory of BBNs is discussed, followed by a discussion on the application of this theory to a specific engine. In particular, the selection of faults and the means by which operating regions for the BBN system are chosen are analyzed. This methodology is then illustrated using the GE CFM56-7 turbofan engine as an example.
{"title":"Bayesian belief networks for fault identification in aircraft gas turbine engines","authors":"T.A. Mast, A. Reed, S. Yurkovich, M. Ashby, S. Adibhatla","doi":"10.1109/CCA.1999.806140","DOIUrl":"https://doi.org/10.1109/CCA.1999.806140","url":null,"abstract":"Describes the methodology for usage of Bayesian belief networks (BBNs) in fault detection for aircraft gas turbine engines. First, the basic theory of BBNs is discussed, followed by a discussion on the application of this theory to a specific engine. In particular, the selection of faults and the means by which operating regions for the BBN system are chosen are analyzed. This methodology is then illustrated using the GE CFM56-7 turbofan engine as an example.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128809703","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}
M. A. Erickson, S. Shah, T. Gudmundsson, P. C. Pandey
Describes a method for rapidly optimizing the uniformity of thin films deposited or grown on semiconductor wafers in batch thermal reactors. The method allows process recipes to be automatically optimized in as few as two process runs. Challenges associated with optimizing process recipes to yield uniform final film thickness on all wafers processed in each batch are presented, and the uniformity problem is formulated as a run-to-run control problem. A solution to this problem is presented that includes a run-to-run process model, an estimator, and a controller. This solution has been implemented in a software package that is used by engineers in the field to optimize process recipes. Measured results are presented from the optimization of two different process recipes.
{"title":"Rapid process recipe optimization for batch thermal reactors","authors":"M. A. Erickson, S. Shah, T. Gudmundsson, P. C. Pandey","doi":"10.1109/CCA.1999.806665","DOIUrl":"https://doi.org/10.1109/CCA.1999.806665","url":null,"abstract":"Describes a method for rapidly optimizing the uniformity of thin films deposited or grown on semiconductor wafers in batch thermal reactors. The method allows process recipes to be automatically optimized in as few as two process runs. Challenges associated with optimizing process recipes to yield uniform final film thickness on all wafers processed in each batch are presented, and the uniformity problem is formulated as a run-to-run control problem. A solution to this problem is presented that includes a run-to-run process model, an estimator, and a controller. This solution has been implemented in a software package that is used by engineers in the field to optimize process recipes. Measured results are presented from the optimization of two different process recipes.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"8 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129435748","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}
This paper deals with modeling, uncertain structure and /spl mu/-synthesis of magnetic bearings. The dynamics of magnetic bearing systems are characterized by their instability and complex dynamics of rotor and electromagnets, hence they should have a robustness for stability and performance against model uncertainties. First we derive a nominal mathematical model of the plant under some assumption, then consider the gap between the real physical system and the obtained nominal design model. This gap has complex structure which is expressed by the structured uncertainties that includes linearization error, parametric uncertainties, unmodeled dynamics, and gyroscopic effect. Then we set the interconnection structure which contains the above structurally represented uncertainties. Next we design a robust controller which achieves robust performance condition using the structured singular value /spl mu/. Finally, we evaluate the proposed interconnection structure and verify robustness of stability and performance of the designed /spl mu/ controller by several numerical simulations.
{"title":"Uncertain model and /spl mu/-synthesis of a magnetic bearing","authors":"T. Namerikawa, M. Fujita","doi":"10.1109/CCA.1999.806706","DOIUrl":"https://doi.org/10.1109/CCA.1999.806706","url":null,"abstract":"This paper deals with modeling, uncertain structure and /spl mu/-synthesis of magnetic bearings. The dynamics of magnetic bearing systems are characterized by their instability and complex dynamics of rotor and electromagnets, hence they should have a robustness for stability and performance against model uncertainties. First we derive a nominal mathematical model of the plant under some assumption, then consider the gap between the real physical system and the obtained nominal design model. This gap has complex structure which is expressed by the structured uncertainties that includes linearization error, parametric uncertainties, unmodeled dynamics, and gyroscopic effect. Then we set the interconnection structure which contains the above structurally represented uncertainties. Next we design a robust controller which achieves robust performance condition using the structured singular value /spl mu/. Finally, we evaluate the proposed interconnection structure and verify robustness of stability and performance of the designed /spl mu/ controller by several numerical simulations.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128179062","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}
A model-based recurrent neural network (MBRNN) is introduced for modeling nonlinear dynamic systems. The topology of MBRNN as well as its initial weights are defined according to the linearized state-space model of the plant. As such, the MBRNN has the ability to incorporate the analytical knowledge of the plant in its formulation. With its original topology intact, the MBRNN can then be trained to represent the plant nonlinearities through modifying its node activation functions, which consist of contours of Gaussian radial basis functions (RBFs). Training involves adjusting the weights of the RBFs so as to modify the contours representing the activation functions. The performance of the MBRNN is demonstrated via several examples. The results indicate that it requires much shorter training than needed by ordinary recurrent networks. This training efficiency is attributed to the MBRNN's fixed topology, which is independent of training.
{"title":"Model-based recurrent neural network for modeling nonlinear dynamic systems","authors":"C. Gan, K. Danai","doi":"10.1109/CCA.1999.801236","DOIUrl":"https://doi.org/10.1109/CCA.1999.801236","url":null,"abstract":"A model-based recurrent neural network (MBRNN) is introduced for modeling nonlinear dynamic systems. The topology of MBRNN as well as its initial weights are defined according to the linearized state-space model of the plant. As such, the MBRNN has the ability to incorporate the analytical knowledge of the plant in its formulation. With its original topology intact, the MBRNN can then be trained to represent the plant nonlinearities through modifying its node activation functions, which consist of contours of Gaussian radial basis functions (RBFs). Training involves adjusting the weights of the RBFs so as to modify the contours representing the activation functions. The performance of the MBRNN is demonstrated via several examples. The results indicate that it requires much shorter training than needed by ordinary recurrent networks. This training efficiency is attributed to the MBRNN's fixed topology, which is independent of training.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117093535","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}
Introduction of an auxiliary input is known to be useful to detect the system fault quickly without affecting the original system behavior in normal mode. Such an auxiliary input is designed to enlarge the distance measured by the Kullback discrimination information measure between the system models corresponding to the normal and the fault modes. However, in practice, the designer hardly knows the exact models. Hence, the optimal auxiliary input should be designed for the case of the system models with uncertainty. Here, the auxiliary input is designed to maximize the distance for the worst combination of system models. Numerical simulation results indicate the applicability of the proposed auxiliary input in fault detection.
{"title":"Optimal auxiliary input for fault detection of systems with model uncertainty","authors":"T. Hatanaka, K. Uosaki","doi":"10.1109/CCA.1999.801183","DOIUrl":"https://doi.org/10.1109/CCA.1999.801183","url":null,"abstract":"Introduction of an auxiliary input is known to be useful to detect the system fault quickly without affecting the original system behavior in normal mode. Such an auxiliary input is designed to enlarge the distance measured by the Kullback discrimination information measure between the system models corresponding to the normal and the fault modes. However, in practice, the designer hardly knows the exact models. Hence, the optimal auxiliary input should be designed for the case of the system models with uncertainty. Here, the auxiliary input is designed to maximize the distance for the worst combination of system models. Numerical simulation results indicate the applicability of the proposed auxiliary input in fault detection.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122701901","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}
We study the effect of model reduction strategies for actuator design and control of a thermal convection loop. The problem concerns flow through a thin pipe in which the Boussinesq approximation for Newtonian viscous flows is assumed.
{"title":"On the design of feedback controllers for a convecting fluid flow via reduced order modeling","authors":"J. Burns, B. King, D. Rubio","doi":"10.1109/CCA.1999.801136","DOIUrl":"https://doi.org/10.1109/CCA.1999.801136","url":null,"abstract":"We study the effect of model reduction strategies for actuator design and control of a thermal convection loop. The problem concerns flow through a thin pipe in which the Boussinesq approximation for Newtonian viscous flows is assumed.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121500110","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}
A method of capturing tumbling objects in a non-gravitational field is proposed, aiming at future on-orbit service missions such as capturing failed satellites or a manned vehicle which loses control, or removing debris. The key technology for this capture is how to compensate for the difference of rotational motions between the chaser and the target at the moment of capture. Most conventional methods use manipulator movement for this objective while keeping the position and attitude of the chaser body constant, which limits the allowable rotational velocity and patterns of the tumbling motion of the target. In the proposed method, the chaser aligns its rotational motion with the target's one by appropriate control before capturing the target, which is expected to enlarge the allowable target rotational motion range. Technical issues to realize it are discussed and our approach to them are proposed, which is verified with some computer simulations and hardware experiments.
{"title":"New method of capturing tumbling object in space and its control aspects","authors":"S. Nakasuka, T. Fujiwara","doi":"10.1109/CCA.1999.800940","DOIUrl":"https://doi.org/10.1109/CCA.1999.800940","url":null,"abstract":"A method of capturing tumbling objects in a non-gravitational field is proposed, aiming at future on-orbit service missions such as capturing failed satellites or a manned vehicle which loses control, or removing debris. The key technology for this capture is how to compensate for the difference of rotational motions between the chaser and the target at the moment of capture. Most conventional methods use manipulator movement for this objective while keeping the position and attitude of the chaser body constant, which limits the allowable rotational velocity and patterns of the tumbling motion of the target. In the proposed method, the chaser aligns its rotational motion with the target's one by appropriate control before capturing the target, which is expected to enlarge the allowable target rotational motion range. Technical issues to realize it are discussed and our approach to them are proposed, which is verified with some computer simulations and hardware experiments.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122608447","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}
G. Fernholz, Wei Wang, S. Engell, K. Fougner, J.-P. Bredehoft
Reactive distillation integrates reaction and separation into one apparatus and offers the possibility to overcome restrictions given by chemical and phase equilibria. The batch and semibatch modes permit a more flexible operation compared to the continuous case especially for multi product plants. Here the heterogeneously catalysed esterification of methanol and acetic acid in a reactive distillation column which is operated in semibatch mode is investigated. The solution of a minimum batch time problem defines the optimal trajectory of the process. The task of feedback control is to track this trajectory in the presence of disturbances and model uncertainties. Due to the nonlinear plant behaviour, robustness properties have to be taken into consideration in the design. The nonlinearity of the system is considered as an uncertainty of the linear nominal model in the optimal operating region. A robust controller is designed using a combination of a loop shaping procedure and frequency response approximation. The linear closed-loop system is stable for the nominal model as well as for the models containing uncertainties. The controller also shows good tracking performance when used with the nonlinear model.
{"title":"Operation and control of a semibatch reactive distillation column","authors":"G. Fernholz, Wei Wang, S. Engell, K. Fougner, J.-P. Bredehoft","doi":"10.1109/CCA.1999.806668","DOIUrl":"https://doi.org/10.1109/CCA.1999.806668","url":null,"abstract":"Reactive distillation integrates reaction and separation into one apparatus and offers the possibility to overcome restrictions given by chemical and phase equilibria. The batch and semibatch modes permit a more flexible operation compared to the continuous case especially for multi product plants. Here the heterogeneously catalysed esterification of methanol and acetic acid in a reactive distillation column which is operated in semibatch mode is investigated. The solution of a minimum batch time problem defines the optimal trajectory of the process. The task of feedback control is to track this trajectory in the presence of disturbances and model uncertainties. Due to the nonlinear plant behaviour, robustness properties have to be taken into consideration in the design. The nonlinearity of the system is considered as an uncertainty of the linear nominal model in the optimal operating region. A robust controller is designed using a combination of a loop shaping procedure and frequency response approximation. The linear closed-loop system is stable for the nominal model as well as for the models containing uncertainties. The controller also shows good tracking performance when used with the nonlinear model.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123431991","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}
The design and implementation of a robust computer control system for balancing and improving the steady state performance of a triple inverted pendulum-cart system is considered. The controller is based on discrete-time H/sub /spl infin// theory. An integrator is used to eliminate the effects of small constant sensor offsets and rail inclinations. Experimental results are reported.
{"title":"Robust control of a triple inverted pendulum","authors":"V. Tsachouridis","doi":"10.1109/CCA.1999.801149","DOIUrl":"https://doi.org/10.1109/CCA.1999.801149","url":null,"abstract":"The design and implementation of a robust computer control system for balancing and improving the steady state performance of a triple inverted pendulum-cart system is considered. The controller is based on discrete-time H/sub /spl infin// theory. An integrator is used to eliminate the effects of small constant sensor offsets and rail inclinations. Experimental results are reported.","PeriodicalId":325193,"journal":{"name":"Proceedings of the 1999 IEEE International Conference on Control Applications (Cat. No.99CH36328)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127638819","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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