Pub Date : 2011-10-13DOI: 10.1109/CCA.2011.6044457
Uros Kalabic, I. Kolmanovsky, J. Buckland, E. Gilbert
In this paper, reference and extended command governors are developed for enforcing constraints in the air path of turbo-charged gasoline engines. These governors are add-on control schemes which protect the engine from violating pointwise-in-time state and control constraints, including compressor surge and actuator limits. Several design choices based on linear engine models at different operating points are compared in terms of response speed, sets of recoverable initial conditions, tolerance of disturbances, and computational complexity. The final design is implemented on the nonlinear engine model. Further, an approach to handle intake manifold pressure overshoot constraints, and a novel form of the extended command governor based on Laguerre's sequences are presented.
{"title":"Reference and extended command governors for control of turbocharged gasoline engines based on linear models","authors":"Uros Kalabic, I. Kolmanovsky, J. Buckland, E. Gilbert","doi":"10.1109/CCA.2011.6044457","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044457","url":null,"abstract":"In this paper, reference and extended command governors are developed for enforcing constraints in the air path of turbo-charged gasoline engines. These governors are add-on control schemes which protect the engine from violating pointwise-in-time state and control constraints, including compressor surge and actuator limits. Several design choices based on linear engine models at different operating points are compared in terms of response speed, sets of recoverable initial conditions, tolerance of disturbances, and computational complexity. The final design is implemented on the nonlinear engine model. Further, an approach to handle intake manifold pressure overshoot constraints, and a novel form of the extended command governor based on Laguerre's sequences are presented.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123039327","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 : 2011-10-13DOI: 10.1109/CCA.2011.6044403
J. Rudat, D. Dashevskiy, Linus Pohle
Stick/slip is a severe type of torsional drillstring oscillation that affects the efficiency of the drilling process and can cause bit damage as well as drillstring failure. Different approaches to mitigate stick/slip oscillations are used in the field, ranging from procedures for optimizing drilling parameters to passive downhole damping devices and active surface controllers. To improve performance, some systems use mathematical models of the rotary system. As the drilling process is subject to permanent changes, model-based control systems can only perform adequately when constantly updated with actual conditions. To date, surface data has been used for this, but some key drilling process characteristics can only be identified with downhole data. By using downhole measurements of drillstring dynamics it is possible to identify model parameters and estimate stick/slip instability regions for changing drilling conditions. A surface-based control system can use this information to maintain optimal weight on bit and rotary speed. This paper describes models to estimate the boundaries of stick/slip instability zones. To validate the approach a field test was performed. During this test, stick/slip instability zones were identified experimentally for various bits while drilling in different formations. Results of the test are summarized in the paper.
{"title":"Model-based stability analysis of torsional drillstring oscillations","authors":"J. Rudat, D. Dashevskiy, Linus Pohle","doi":"10.1109/CCA.2011.6044403","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044403","url":null,"abstract":"Stick/slip is a severe type of torsional drillstring oscillation that affects the efficiency of the drilling process and can cause bit damage as well as drillstring failure. Different approaches to mitigate stick/slip oscillations are used in the field, ranging from procedures for optimizing drilling parameters to passive downhole damping devices and active surface controllers. To improve performance, some systems use mathematical models of the rotary system. As the drilling process is subject to permanent changes, model-based control systems can only perform adequately when constantly updated with actual conditions. To date, surface data has been used for this, but some key drilling process characteristics can only be identified with downhole data. By using downhole measurements of drillstring dynamics it is possible to identify model parameters and estimate stick/slip instability regions for changing drilling conditions. A surface-based control system can use this information to maintain optimal weight on bit and rotary speed. This paper describes models to estimate the boundaries of stick/slip instability zones. To validate the approach a field test was performed. During this test, stick/slip instability zones were identified experimentally for various bits while drilling in different formations. Results of the test are summarized in the paper.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"33 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127101230","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 : 2011-10-13DOI: 10.1109/CCA.2011.6044513
F. Saupe, H. Pfifer
This paper describes the application of linear parameter varying (LPV) control design to the positioning control of the first axis of an industrial manipulator. The manipulator is modeled as a single flexible joint robot. The parameter dependency of the manipulator dynamics results from movements of the other axes. They determine the inertia that has to be moved by the first axis. The controller is designed via a mixed sensitivity weighting scheme for LPV control. Structural properties of the weighting scheme allow the application of the separation principle. By splitting the synthesis problem into an observer and a state feedback problem, the complexity of the convex optimization problem which has to be solved is greatly reduced. A multistage parameter optimization is employed to tune the control system. Finally, the design is compared to an output feedback PID and an ad-hoc gain-scheduled observer based PI state feedback controller on a real-time testbed with a KUKA standard industrial manipulator.
{"title":"Applied LPV control exploiting the separation principle for the single axis positioning of an industrial manipulator","authors":"F. Saupe, H. Pfifer","doi":"10.1109/CCA.2011.6044513","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044513","url":null,"abstract":"This paper describes the application of linear parameter varying (LPV) control design to the positioning control of the first axis of an industrial manipulator. The manipulator is modeled as a single flexible joint robot. The parameter dependency of the manipulator dynamics results from movements of the other axes. They determine the inertia that has to be moved by the first axis. The controller is designed via a mixed sensitivity weighting scheme for LPV control. Structural properties of the weighting scheme allow the application of the separation principle. By splitting the synthesis problem into an observer and a state feedback problem, the complexity of the convex optimization problem which has to be solved is greatly reduced. A multistage parameter optimization is employed to tune the control system. Finally, the design is compared to an output feedback PID and an ad-hoc gain-scheduled observer based PI state feedback controller on a real-time testbed with a KUKA standard industrial manipulator.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"2006 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125832362","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 : 2011-10-13DOI: 10.1109/CCA.2011.6044478
H. Alwi, C. Edwards, M. T. Hamayun
This paper presents a nonlinear fault tolerant scheme for longitudinal control of an aircraft. The proposed approach uses an integral sliding mode control allocation scheme which can be built around any existing controller. In nominal fault free conditions, only the baseline controller and the primary control surface associated with it will be active. When faults/failures occur in the control surfaces, the proposed sliding mode control allocation scheme becomes active to provide extra robustness, and to redistribute the control signals to the redundant secondary control surfaces. In this paper the baseline controller considered is an existing backstepping one from the literature, designed for flight path angle tracking based on the nonlinear equations of motion. The simulations on a high fidelity aircraft benchmark model show good results for nominal and fault/failure conditions even in the presence of unmodelled dynamics.
{"title":"Nonlinear integral sliding mode fault tolerant longitudinal aircraft control","authors":"H. Alwi, C. Edwards, M. T. Hamayun","doi":"10.1109/CCA.2011.6044478","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044478","url":null,"abstract":"This paper presents a nonlinear fault tolerant scheme for longitudinal control of an aircraft. The proposed approach uses an integral sliding mode control allocation scheme which can be built around any existing controller. In nominal fault free conditions, only the baseline controller and the primary control surface associated with it will be active. When faults/failures occur in the control surfaces, the proposed sliding mode control allocation scheme becomes active to provide extra robustness, and to redistribute the control signals to the redundant secondary control surfaces. In this paper the baseline controller considered is an existing backstepping one from the literature, designed for flight path angle tracking based on the nonlinear equations of motion. The simulations on a high fidelity aircraft benchmark model show good results for nominal and fault/failure conditions even in the presence of unmodelled dynamics.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126971042","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 : 2011-10-13DOI: 10.1109/CCA.2011.6044497
Ganga P. Jayaraman, Stephen V. Lunzman
This paper describes the modeling and analysis of the dynamics of an electronic load sensing hydraulic system consisting of a load sensing pump, a flow control valve, a hydraulic cylinder and an effective mass representing the linkage inertia. Load sensing hydraulic circuits are prone to instabilities and frequently require hydraulic filters in the form of orifices and control volumes to remove unwanted oscillations. Closed loop controllers for such systems are difficult to design due to the nonlinearities and high order transfer functions. In this paper a linear model is derived from equations of motion, and validated against a nonlinear simulation model based on MATLAB. Then, a third order model is derived that can be used for controller design.
{"title":"Modeling and analysis of an electronic load sensing pump","authors":"Ganga P. Jayaraman, Stephen V. Lunzman","doi":"10.1109/CCA.2011.6044497","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044497","url":null,"abstract":"This paper describes the modeling and analysis of the dynamics of an electronic load sensing hydraulic system consisting of a load sensing pump, a flow control valve, a hydraulic cylinder and an effective mass representing the linkage inertia. Load sensing hydraulic circuits are prone to instabilities and frequently require hydraulic filters in the form of orifices and control volumes to remove unwanted oscillations. Closed loop controllers for such systems are difficult to design due to the nonlinearities and high order transfer functions. In this paper a linear model is derived from equations of motion, and validated against a nonlinear simulation model based on MATLAB. Then, a third order model is derived that can be used for controller design.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115174875","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 : 2011-10-13DOI: 10.1109/CCA.2011.6044450
I. Houtzager, J. Wingerden, M. Verhaegen
A repetitive control method is presented that is implemented in real-time for periodic wind disturbance rejection for linear systems with multi inputs and multi outputs and with both repetitive and non-repetitive disturbance components. The novel repetitive controller can learn the periodic wind disturbances for fixed-speed wind turbines and variable-speed wind turbines operating above-rated and we will demonstrate this on an experimental “smart” rotor test section. The “smart” rotor is a rotor where the blades are equipped with a number of control devices that locally change the lift profile on the blade, combined with appropriate sensors and controllers. The rotational speed of wind turbines operating above-rated will vary around a defined reference speed, therefore methods are given to robustify the repetitive controllers for a mismatch in the period. The design of the repetitive controller is formulated as a lifted linear stochastic output-feedback problem on which the mature techniques of discrete linear control may be applied. With relatively slow changing periodic disturbances it is shown that this control method can significantly reduce the structural vibrations of the “smart” rotor test section. The cost of additional wear and tear of the “smart” actuators are kept small, because a smooth control action is generated as the controller mainly focuses on the reduction of periodic disturbances.
{"title":"Rejection of periodic wind disturbances on an experimental “smart” rotor section using lifted repetitive control","authors":"I. Houtzager, J. Wingerden, M. Verhaegen","doi":"10.1109/CCA.2011.6044450","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044450","url":null,"abstract":"A repetitive control method is presented that is implemented in real-time for periodic wind disturbance rejection for linear systems with multi inputs and multi outputs and with both repetitive and non-repetitive disturbance components. The novel repetitive controller can learn the periodic wind disturbances for fixed-speed wind turbines and variable-speed wind turbines operating above-rated and we will demonstrate this on an experimental “smart” rotor test section. The “smart” rotor is a rotor where the blades are equipped with a number of control devices that locally change the lift profile on the blade, combined with appropriate sensors and controllers. The rotational speed of wind turbines operating above-rated will vary around a defined reference speed, therefore methods are given to robustify the repetitive controllers for a mismatch in the period. The design of the repetitive controller is formulated as a lifted linear stochastic output-feedback problem on which the mature techniques of discrete linear control may be applied. With relatively slow changing periodic disturbances it is shown that this control method can significantly reduce the structural vibrations of the “smart” rotor test section. The cost of additional wear and tear of the “smart” actuators are kept small, because a smooth control action is generated as the controller mainly focuses on the reduction of periodic disturbances.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122493210","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 : 2011-10-13DOI: 10.1109/CCA.2011.6044376
M. Baar, W. Bongers, M. Berkel, N. Doelman, B. Hennen, P. Nuij, J. Oosterbeek, M. Steinbuch, E. Westerhof, G. Witvoet
Resistive magneto-hydrodynamic instabilities are expected to limit the performance of nuclear fusion reactors. Prime examples are the sawtooth instability and the neoclassical tearing modes. The sawtooth instability will affect the refueling of the plasma core and the fast particle concentration. In reactor relevant conditions, the sawtooth can also trigger secondary instabilities. These are the neo-classical tearing modes, which can deteriorate the plasma performance or even disrupt the discharge. These modes (sawteeth and tearing modes) appear at specific locations in the tokamak plasma, associated with the distribution of the current density and the toroidal magnetic field. Localized current drive from electron cyclotron waves is foreseen as a possible actuator for the width of the tearing modes and the period of the sawteeth. Magnetic pick-up coils, electron cyclotron emission (ECE) and soft X-ray emission are the most likely sensors. A system approach for real-time detection, localisation and control of resistive magneto-hydrodynamic modes in tokamaks is presented. The system combines an ECE diagnostic for sensing of the instabilities in the same sight-line with a steerable Electron Cyclotron Resonant Heating and Current Drive (ECRH/CD) antenna. A model for the sawtooth is used to derive the linearized input-output relations (transfer functions) from the varying deposition location of high power Electron Cyclotron waves to the sawtooth period. The transfer functions are derived around a large collection of operating points. Proportional-integral-integral (PII) action can be applied to achieve fast and perfect tracking, while satisfying robustness constraints. The launcher dynamics seriously affects the closed loop performance in present-day experiments. Special emphasis is put on the issue of real-time sawtooth period detection. An algorithm based on time-scale wavelet theory and edge detection for accurate real-time sawtooth period estimation has been developed. The period is estimated by detecting subsequent crashes. The realized accuracy of the detection algorithm is well below the uncertainty of the crash period for most crashes. Multi-resolution analysis enables distinction between different sizes of sawtooth crashes due to the different sizes of wavelets (scales), resulting in an algorithm, which is robust and accurate. A methodology for fast detection of q = m/n = 2/1 tearing modes and retrieval of their location, rotation frequency and phase is presented. Set-points to establish alignment of the ECRH/CD deposition location with the centre of the tearing mode are generated in real-time and forwarded in closed-loop to the steerable launcher and as a modulation pulse train to the gyrotron.
{"title":"Control of sawteeth and neo-classical tearing modes in tokamaks using electron cyclotron waves","authors":"M. Baar, W. Bongers, M. Berkel, N. Doelman, B. Hennen, P. Nuij, J. Oosterbeek, M. Steinbuch, E. Westerhof, G. Witvoet","doi":"10.1109/CCA.2011.6044376","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044376","url":null,"abstract":"Resistive magneto-hydrodynamic instabilities are expected to limit the performance of nuclear fusion reactors. Prime examples are the sawtooth instability and the neoclassical tearing modes. The sawtooth instability will affect the refueling of the plasma core and the fast particle concentration. In reactor relevant conditions, the sawtooth can also trigger secondary instabilities. These are the neo-classical tearing modes, which can deteriorate the plasma performance or even disrupt the discharge. These modes (sawteeth and tearing modes) appear at specific locations in the tokamak plasma, associated with the distribution of the current density and the toroidal magnetic field. Localized current drive from electron cyclotron waves is foreseen as a possible actuator for the width of the tearing modes and the period of the sawteeth. Magnetic pick-up coils, electron cyclotron emission (ECE) and soft X-ray emission are the most likely sensors. A system approach for real-time detection, localisation and control of resistive magneto-hydrodynamic modes in tokamaks is presented. The system combines an ECE diagnostic for sensing of the instabilities in the same sight-line with a steerable Electron Cyclotron Resonant Heating and Current Drive (ECRH/CD) antenna. A model for the sawtooth is used to derive the linearized input-output relations (transfer functions) from the varying deposition location of high power Electron Cyclotron waves to the sawtooth period. The transfer functions are derived around a large collection of operating points. Proportional-integral-integral (PII) action can be applied to achieve fast and perfect tracking, while satisfying robustness constraints. The launcher dynamics seriously affects the closed loop performance in present-day experiments. Special emphasis is put on the issue of real-time sawtooth period detection. An algorithm based on time-scale wavelet theory and edge detection for accurate real-time sawtooth period estimation has been developed. The period is estimated by detecting subsequent crashes. The realized accuracy of the detection algorithm is well below the uncertainty of the crash period for most crashes. Multi-resolution analysis enables distinction between different sizes of sawtooth crashes due to the different sizes of wavelets (scales), resulting in an algorithm, which is robust and accurate. A methodology for fast detection of q = m/n = 2/1 tearing modes and retrieval of their location, rotation frequency and phase is presented. Set-points to establish alignment of the ECRH/CD deposition location with the centre of the tearing mode are generated in real-time and forwarded in closed-loop to the steerable launcher and as a modulation pulse train to the gyrotron.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128622500","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 : 2011-10-13DOI: 10.1109/CCA.2011.6044391
S. Agrawal, Ying Mao, G. Downton, Jahir Padon, Kuo-Chaing Chen
The goal of this paper is to investigate how the vibration characteristics within a drill pipe can be modulated using (i) active control laws, or (ii) appropriate choices of impedance properties within the continuum. It is assumed in the paper that the continuum could have multiple sources of inputs, some acting as disturbance and some as control. The continuum was assumed to have generalized impedance at the two boundaries. In the paper, the structure of the transfer function is derived. Then, control laws are developed using the infinite dimensional models to actively modulate vibration characteristics within the continuum. Multi-sensor implementation of these control laws is then investigated which would provide these sought performances without requiring knowledge of the boundary impedance. Additionally, the role of boundary impedance on the performance of the control law is investigated. The concepts proposed in this paper are illustrated by simulations.
{"title":"Control of longitudinal or torsional vibration in a drill pipe/BHA using infinite dimensional techniques","authors":"S. Agrawal, Ying Mao, G. Downton, Jahir Padon, Kuo-Chaing Chen","doi":"10.1109/CCA.2011.6044391","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044391","url":null,"abstract":"The goal of this paper is to investigate how the vibration characteristics within a drill pipe can be modulated using (i) active control laws, or (ii) appropriate choices of impedance properties within the continuum. It is assumed in the paper that the continuum could have multiple sources of inputs, some acting as disturbance and some as control. The continuum was assumed to have generalized impedance at the two boundaries. In the paper, the structure of the transfer function is derived. Then, control laws are developed using the infinite dimensional models to actively modulate vibration characteristics within the continuum. Multi-sensor implementation of these control laws is then investigated which would provide these sought performances without requiring knowledge of the boundary impedance. Additionally, the role of boundary impedance on the performance of the control law is investigated. The concepts proposed in this paper are illustrated by simulations.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126692642","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 : 2011-10-13DOI: 10.1109/CCA.2011.6044489
Benjamin Hartmann, J. Moll, O. Nelles, C. Fritzen
In this paper, we propose an effective and time-saving algorithm for model-based design of experiments in the framework of a structural health monitoring system. The goal is to identify and locate structural defects in plate-like geometries. The new idea combines a pseudo-random Monte-Carlo sampling with a local model network. The global distribution of data points is based on the input space partitioning which can be seen as a mapping of the non-linearities of the underlying process. This results in an active learning strategy that incorporates the process behavior into the experimental design strategy. The application of the proposed algorithm for ultrasonic imaging in an isotropic non-convex structure shows great potential. It is shown that in contrast to a grid-based approach the spatial discretization can be optimized with high accuracy and adaptivity.
{"title":"Hierarchical local model trees for design of experiments in the framework of ultrasonic structural health monitoring","authors":"Benjamin Hartmann, J. Moll, O. Nelles, C. Fritzen","doi":"10.1109/CCA.2011.6044489","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044489","url":null,"abstract":"In this paper, we propose an effective and time-saving algorithm for model-based design of experiments in the framework of a structural health monitoring system. The goal is to identify and locate structural defects in plate-like geometries. The new idea combines a pseudo-random Monte-Carlo sampling with a local model network. The global distribution of data points is based on the input space partitioning which can be seen as a mapping of the non-linearities of the underlying process. This results in an active learning strategy that incorporates the process behavior into the experimental design strategy. The application of the proposed algorithm for ultrasonic imaging in an isotropic non-convex structure shows great potential. It is shown that in contrast to a grid-based approach the spatial discretization can be optimized with high accuracy and adaptivity.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123398131","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 : 2011-10-13DOI: 10.1109/CCA.2011.6044356
John Barnes, K. Ariyur
We propose a novel solar sensor geometry utilizing a hemispherical arrangement of pixels to determine the vector to the dominant light source in its environment. We show two methods for calculating this vector: one based on transforming the problem from an optical one into a geometric one, and another using a least squares approach to minimize the error function for the sensor. These methods do not depend on the physical details of any particular sensor design. Both methods rely upon certain assumptions, but methods for extracting an accurate sun vector are discussed which do not rely upon such an idealized environment. Using the estimate of the sun vector, it is possible to determine the location of the sensor on the Earth. Applications include position measurement and navigation for UAVs, UGVs, and other mobile platforms.
{"title":"Miniaturizing the spherical sundial: A hemispherical sensor for orientation and positioning with respect to point sources of light","authors":"John Barnes, K. Ariyur","doi":"10.1109/CCA.2011.6044356","DOIUrl":"https://doi.org/10.1109/CCA.2011.6044356","url":null,"abstract":"We propose a novel solar sensor geometry utilizing a hemispherical arrangement of pixels to determine the vector to the dominant light source in its environment. We show two methods for calculating this vector: one based on transforming the problem from an optical one into a geometric one, and another using a least squares approach to minimize the error function for the sensor. These methods do not depend on the physical details of any particular sensor design. Both methods rely upon certain assumptions, but methods for extracting an accurate sun vector are discussed which do not rely upon such an idealized environment. Using the estimate of the sun vector, it is possible to determine the location of the sensor on the Earth. Applications include position measurement and navigation for UAVs, UGVs, and other mobile platforms.","PeriodicalId":208713,"journal":{"name":"2011 IEEE International Conference on Control Applications (CCA)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114230601","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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