Pub Date : 2016-06-21DOI: 10.1109/MED.2016.7535868
Prasanna Kannappan, Konstantinos Karydis, H. Tanner, Adam Jardine, Jeffrey Heinz
The paper demonstrates that aspects of resilience of supervisory Cyber-Physical Systems (CPSs) can be improved through the inclusion of appropriate learning modules in the subordinate autonomous agents. During normal operation, individual agents keep track of their supervisor's commands and utilize the learning module, based on Grammatical Inference, to learn aspects of the organizational structure of the general system and role assignments. It is shown that in cases that the supervisor fails or communication to subordinates is disrupted, these agents are able to recover normalcy of operations. Guaranteeing normalcy recovery in supervisory CPSs is critical in cases of a catastrophic failure or malicious attack.
{"title":"Incorporating learning modules improves aspects of resilience of supervisory cyber-physical systems","authors":"Prasanna Kannappan, Konstantinos Karydis, H. Tanner, Adam Jardine, Jeffrey Heinz","doi":"10.1109/MED.2016.7535868","DOIUrl":"https://doi.org/10.1109/MED.2016.7535868","url":null,"abstract":"The paper demonstrates that aspects of resilience of supervisory Cyber-Physical Systems (CPSs) can be improved through the inclusion of appropriate learning modules in the subordinate autonomous agents. During normal operation, individual agents keep track of their supervisor's commands and utilize the learning module, based on Grammatical Inference, to learn aspects of the organizational structure of the general system and role assignments. It is shown that in cases that the supervisor fails or communication to subordinates is disrupted, these agents are able to recover normalcy of operations. Guaranteeing normalcy recovery in supervisory CPSs is critical in cases of a catastrophic failure or malicious attack.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126050472","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 : 2016-06-21DOI: 10.1109/MED.2016.7535962
G. Chalvatzaki, X. Papageorgiou, Christian Werner, K. Hauer, C. Tzafestas, P. Maragos
Towards a mobility assistance robot for the elderly, it is essential to develop a robust and accurate gait tracking system. Various pathologies cause mobility inabilities to the aged population, leading to different gait patterns and walking speed. In this work, we present the experimental comparison of two user leg tracking systems of a robotic assistance walker, using data collected by a laser range sensor. The first one is a Kalman Filter tracking system, while the second one proposes the use of Particle Filters. The tracking systems provide the positions and velocities of the user's legs, which are used as observations into an HMM-based gait phases recognition system. The spatiotemporal results of the HMM framework are employed for computing parameters that characterize the human motion, which subsequently can be used to assess and distinguish between possible motion disabilities. For the experimental comparison, we are using real data collected from an ensemble of different elderly persons with a number of pathologies, and ground truth data from a GaitRite System. The results presented in this work, demonstrate the applicability of the tracking systems in real test cases.
{"title":"Experimental comparison of human gait tracking algorithms: Towards a context-aware mobility assistance robotic walker","authors":"G. Chalvatzaki, X. Papageorgiou, Christian Werner, K. Hauer, C. Tzafestas, P. Maragos","doi":"10.1109/MED.2016.7535962","DOIUrl":"https://doi.org/10.1109/MED.2016.7535962","url":null,"abstract":"Towards a mobility assistance robot for the elderly, it is essential to develop a robust and accurate gait tracking system. Various pathologies cause mobility inabilities to the aged population, leading to different gait patterns and walking speed. In this work, we present the experimental comparison of two user leg tracking systems of a robotic assistance walker, using data collected by a laser range sensor. The first one is a Kalman Filter tracking system, while the second one proposes the use of Particle Filters. The tracking systems provide the positions and velocities of the user's legs, which are used as observations into an HMM-based gait phases recognition system. The spatiotemporal results of the HMM framework are employed for computing parameters that characterize the human motion, which subsequently can be used to assess and distinguish between possible motion disabilities. For the experimental comparison, we are using real data collected from an ensemble of different elderly persons with a number of pathologies, and ground truth data from a GaitRite System. The results presented in this work, demonstrate the applicability of the tracking systems in real test cases.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123396652","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 : 2016-06-21DOI: 10.1109/MED.2016.7535888
Leonidas Droukas, G. Rovithakis, Z. Doulgeri
In this work the problem of designing a low complexity state feedback controller which enforces the domination of the rolling motion of a spherical robotic fingertip upon a curved surface is considered. Fingertip rolling is essential for robot object fine positioning and manipulation and should be explicitly considered as a control objective. The prescribed performance control methodology is employed. Under the designed controller, the sliding and spinning regime of the robot tip motion is quickly suppressed, a desired position and normal force is reached with prespecified transient and steady state behavior while contact maintenance is guaranteed. Simulations validate the approach.
{"title":"Robot finger control for rolling on curved surfaces","authors":"Leonidas Droukas, G. Rovithakis, Z. Doulgeri","doi":"10.1109/MED.2016.7535888","DOIUrl":"https://doi.org/10.1109/MED.2016.7535888","url":null,"abstract":"In this work the problem of designing a low complexity state feedback controller which enforces the domination of the rolling motion of a spherical robotic fingertip upon a curved surface is considered. Fingertip rolling is essential for robot object fine positioning and manipulation and should be explicitly considered as a control objective. The prescribed performance control methodology is employed. Under the designed controller, the sliding and spinning regime of the robot tip motion is quickly suppressed, a desired position and normal force is reached with prespecified transient and steady state behavior while contact maintenance is guaranteed. Simulations validate the approach.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117238531","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 : 2016-06-21DOI: 10.1109/MED.2016.7535872
V. Vasilyev
The problem of neural network structure selection is discussed. The constructive approach to shallow NNs design based on using the minimal complexity principle is offered. The peculiarities of its application to solving different classes of tasks often met with in practice are considered.
{"title":"Structural design of shallow neural networks on the basis of minimal complexity principle","authors":"V. Vasilyev","doi":"10.1109/MED.2016.7535872","DOIUrl":"https://doi.org/10.1109/MED.2016.7535872","url":null,"abstract":"The problem of neural network structure selection is discussed. The constructive approach to shallow NNs design based on using the minimal complexity principle is offered. The peculiarities of its application to solving different classes of tasks often met with in practice are considered.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128767635","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 : 2016-06-21DOI: 10.1109/MED.2016.7535847
A. Benzaouia, M. Ouladsine, B. Ananou, A. Naamane
In this paper, fault tolerant control (FTC) problem for discrete-time switching systems with delay and constrained input is studied. Sufficient conditions of building an observer are obtained by using common Lyapunov function. These conditions are worked out using cone complementarity technique. The obtained results are applied on a numerical example showing fault detection, localization of fault and reconfiguration of the control to maintain asymptotic stability even in presence of a permanent sensor fault and constraints on the control.
{"title":"Fault tolerant constrained control for switching discrete-time systems with delays","authors":"A. Benzaouia, M. Ouladsine, B. Ananou, A. Naamane","doi":"10.1109/MED.2016.7535847","DOIUrl":"https://doi.org/10.1109/MED.2016.7535847","url":null,"abstract":"In this paper, fault tolerant control (FTC) problem for discrete-time switching systems with delay and constrained input is studied. Sufficient conditions of building an observer are obtained by using common Lyapunov function. These conditions are worked out using cone complementarity technique. The obtained results are applied on a numerical example showing fault detection, localization of fault and reconfiguration of the control to maintain asymptotic stability even in presence of a permanent sensor fault and constraints on the control.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129422388","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 : 2016-06-21DOI: 10.1109/MED.2016.7535884
H. Oh, Hyo-Sang Shin, Seungkeun Kim, Pawel Ladosz, Wen‐Hua Chen
This paper proposes a communication-aware trajectory planning approach for UAVs to relay data/information (e.g. live surveillance feed) between a ground control station and friendly ground vehicles (a convoy) moving in a complex urban area. UAVs are controlled to stay: i) within the communication-feasible area (having a direct line-of-sight to the moving convoy and within the maximum communication range) and ii) as close as possible to the convoy to have better communication quality, while satisfying their kinematic and dynamic constraints. Numerical simulations and a proof-of-concept indoor flight test have been performed to validate the benefit and feasibility of the proposed algorithm.
{"title":"Communication-aware convoy following guidance for UAVs in a complex urban environment","authors":"H. Oh, Hyo-Sang Shin, Seungkeun Kim, Pawel Ladosz, Wen‐Hua Chen","doi":"10.1109/MED.2016.7535884","DOIUrl":"https://doi.org/10.1109/MED.2016.7535884","url":null,"abstract":"This paper proposes a communication-aware trajectory planning approach for UAVs to relay data/information (e.g. live surveillance feed) between a ground control station and friendly ground vehicles (a convoy) moving in a complex urban area. UAVs are controlled to stay: i) within the communication-feasible area (having a direct line-of-sight to the moving convoy and within the maximum communication range) and ii) as close as possible to the convoy to have better communication quality, while satisfying their kinematic and dynamic constraints. Numerical simulations and a proof-of-concept indoor flight test have been performed to validate the benefit and feasibility of the proposed algorithm.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121196758","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 : 2016-06-21DOI: 10.1109/MED.2016.7535992
D. Materassi
The article tackles the problem of inferring information about the unknown structure of a network of dynamic systems under the assumption that the systems are connected according to a tree topology. In particular, the article introduces methodologies to address the presence of hidden (unmeasured) nodes in a scenario where only non-invasive observations are available. By non-invasive observations, it is meant that no known input signal is actively injected into the network. The whole system instead is assumed to be forced by unknown external excitations modeled as stochastic processes. No a priori assumption is made about the number and location of the hidden nodes. Current approaches are capable of consistently inferring the network structure from data, when the dynamics are linear and/or the measurements have a jointly Gaussian distribution. This work provides an approach that can also be applied to networks with nonlinear dynamics and non-Gaussian disturbances. Sufficient conditions are found under which a consistent reconstruction of the topology can be obtained.
{"title":"Reconstructing tree structures of dynamic systems with hidden nodes under nonlinear dynamics","authors":"D. Materassi","doi":"10.1109/MED.2016.7535992","DOIUrl":"https://doi.org/10.1109/MED.2016.7535992","url":null,"abstract":"The article tackles the problem of inferring information about the unknown structure of a network of dynamic systems under the assumption that the systems are connected according to a tree topology. In particular, the article introduces methodologies to address the presence of hidden (unmeasured) nodes in a scenario where only non-invasive observations are available. By non-invasive observations, it is meant that no known input signal is actively injected into the network. The whole system instead is assumed to be forced by unknown external excitations modeled as stochastic processes. No a priori assumption is made about the number and location of the hidden nodes. Current approaches are capable of consistently inferring the network structure from data, when the dynamics are linear and/or the measurements have a jointly Gaussian distribution. This work provides an approach that can also be applied to networks with nonlinear dynamics and non-Gaussian disturbances. Sufficient conditions are found under which a consistent reconstruction of the topology can be obtained.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114323435","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 : 2016-06-21DOI: 10.1109/MED.2016.7535993
Maximilian Mühlegg, Girish V. Chowdhary, F. Holzapfel
Certification of adaptive control algorithms for use on aerospace applications has not yet been accomplished in the aerospace industry. According to an emerging consensus between various authors, online monitoring and health assessment will play an integral role in closing this gap. In this paper we propose a monitoring system for Model Reference Adaptive Controllers, which enables online detection of future state requirement violations. We achieve this by employing Gaussian Process regression, which leads to a belief on the uncertainty in the system dynamics. Using analytic time-series forecasting, the system dynamics can be projected into the future, thus allowing for a statistical assertion whether a state requirement will be violated during the prediction horizon. We show the concept in numerical simulation.
{"title":"State monitoring of systems augmented by model reference adaptive control using analytic time-series forecasting","authors":"Maximilian Mühlegg, Girish V. Chowdhary, F. Holzapfel","doi":"10.1109/MED.2016.7535993","DOIUrl":"https://doi.org/10.1109/MED.2016.7535993","url":null,"abstract":"Certification of adaptive control algorithms for use on aerospace applications has not yet been accomplished in the aerospace industry. According to an emerging consensus between various authors, online monitoring and health assessment will play an integral role in closing this gap. In this paper we propose a monitoring system for Model Reference Adaptive Controllers, which enables online detection of future state requirement violations. We achieve this by employing Gaussian Process regression, which leads to a belief on the uncertainty in the system dynamics. Using analytic time-series forecasting, the system dynamics can be projected into the future, thus allowing for a statistical assertion whether a state requirement will be violated during the prediction horizon. We show the concept in numerical simulation.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114713947","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 : 2016-06-21DOI: 10.1109/MED.2016.7535937
A. Pătraşcu, I. Necoara
In this paper we introduce a primal projected gradient method based on inexact projections for solving constrained convex problems. For this algorithm we prove sublinear rate of convergence when applied to problems with objective function being convex and having Lipschitz gradient. At each iteration, our method computes a gradient step towards the solution of the unconstrained problem and then projecting approximately this step onto the feasible set. We recast the inexact projection as approximately solving a best approximation problem for the gradient step until a certain stopping criterion holds. Finally, we show that there are available powerful algorithms, with linear convergence, for computing the inexact projection, such as Dykstra algorithm and alternating direction method of multipliers. Our algorithm is especially useful in embedded model predictive control on hardware with limited computational power, where tight bounds on the computational complexity of the numerical algorithm, used for solving the control problem, are required.
{"title":"Complexity certifications of inexact projection primal gradient method for convex problems: Application to embedded MPC","authors":"A. Pătraşcu, I. Necoara","doi":"10.1109/MED.2016.7535937","DOIUrl":"https://doi.org/10.1109/MED.2016.7535937","url":null,"abstract":"In this paper we introduce a primal projected gradient method based on inexact projections for solving constrained convex problems. For this algorithm we prove sublinear rate of convergence when applied to problems with objective function being convex and having Lipschitz gradient. At each iteration, our method computes a gradient step towards the solution of the unconstrained problem and then projecting approximately this step onto the feasible set. We recast the inexact projection as approximately solving a best approximation problem for the gradient step until a certain stopping criterion holds. Finally, we show that there are available powerful algorithms, with linear convergence, for computing the inexact projection, such as Dykstra algorithm and alternating direction method of multipliers. Our algorithm is especially useful in embedded model predictive control on hardware with limited computational power, where tight bounds on the computational complexity of the numerical algorithm, used for solving the control problem, are required.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114780976","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 : 2016-06-21DOI: 10.1109/MED.2016.7535940
S. Ioannou, K. Dalamagkidis, E. Stefanakos, K. Valavanis, P. H. Wiley
Peukert's equation describes the relationship between battery capacity and discharge current for lead acid batteries. The relationship is known and widely used to this day. This paper re-examines Peukert's equation and investigate its' validity with state of the art lead acid and lithium batteries. Experimental data reveals that for the same battery, Peukert's exponent is not constant but it is a function of battery capacity and discharge current. This work proposes and validates a reformulated equation which provides an accurate prediction of the runtime for single discharge applications using only the battery name plate information such as capacity and the corresponding discharge time. The validation includes lead acid and lithium batteries. Finally, this work introduces and validates a methodology where the battery parameters can be determined in less than one hour when no battery data and usage is available.
{"title":"Runtime, capacity and discharge current relationship for lead acid and lithium batteries","authors":"S. Ioannou, K. Dalamagkidis, E. Stefanakos, K. Valavanis, P. H. Wiley","doi":"10.1109/MED.2016.7535940","DOIUrl":"https://doi.org/10.1109/MED.2016.7535940","url":null,"abstract":"Peukert's equation describes the relationship between battery capacity and discharge current for lead acid batteries. The relationship is known and widely used to this day. This paper re-examines Peukert's equation and investigate its' validity with state of the art lead acid and lithium batteries. Experimental data reveals that for the same battery, Peukert's exponent is not constant but it is a function of battery capacity and discharge current. This work proposes and validates a reformulated equation which provides an accurate prediction of the runtime for single discharge applications using only the battery name plate information such as capacity and the corresponding discharge time. The validation includes lead acid and lithium batteries. Finally, this work introduces and validates a methodology where the battery parameters can be determined in less than one hour when no battery data and usage is available.","PeriodicalId":428139,"journal":{"name":"2016 24th Mediterranean Conference on Control and Automation (MED)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124453449","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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