Pub Date : 2011-06-20DOI: 10.1109/MED.2011.5983137
Dimitra Triantafyllou, P. Koustoumpardis, N. Aspragathos
A fuzzy model reference adaptive controller for regulating the fabric's tensional forces applied by a robot during the sewing task is developed. The adaptive fuzzy logic controller closes the loop outside the internal scara robot controller. The robot guides a piece of fabric in a conventional industrial sewing machine while its controller maintains a desired constant tensional force applied to the fabric during the sewing process. In each loop, the proposed controller calculates the appropriate robot end-effector displacement. A force sensor mounted on the wrist of the robot manipulator measures the actual force applied to the fabric, and the formulated force error is used in order to adapt the controllers' parameters. The performance of the controller is investigated experimentally and the results show the effectiveness of the FMRL approach and its wide range of applications.
{"title":"Model reference fuzzy learning force control for robotized sewing","authors":"Dimitra Triantafyllou, P. Koustoumpardis, N. Aspragathos","doi":"10.1109/MED.2011.5983137","DOIUrl":"https://doi.org/10.1109/MED.2011.5983137","url":null,"abstract":"A fuzzy model reference adaptive controller for regulating the fabric's tensional forces applied by a robot during the sewing task is developed. The adaptive fuzzy logic controller closes the loop outside the internal scara robot controller. The robot guides a piece of fabric in a conventional industrial sewing machine while its controller maintains a desired constant tensional force applied to the fabric during the sewing process. In each loop, the proposed controller calculates the appropriate robot end-effector displacement. A force sensor mounted on the wrist of the robot manipulator measures the actual force applied to the fabric, and the formulated force error is used in order to adapt the controllers' parameters. The performance of the controller is investigated experimentally and the results show the effectiveness of the FMRL approach and its wide range of applications.","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115170216","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 : 2011-06-20DOI: 10.1109/MED.2011.5983107
Christoforos Keroglou, C. Hadjicostis
In this paper we consider the problem of classifying a sequence of observations among two known hidden Markov models (HMMs). We use a classifier that minimizes the probability of error (i.e., the probability of misclassification), and we are interested in assessing its performance by computing the a priori probability of error (before any observations are made). This probability (that the classifier makes an incorrect decision) can be obtained, as a function of the length of the sequence of observations, by summing up the probability of misclassification over all possible observation sequences, weighted by their corresponding probabilities. In an effort to avoid the high complexity associated with the computation of the exact probability of error, we establish an upper bound on the probability of error, and we find the necessary and sufficient conditions for this bound to tend to zero exponentially with the number of observation steps. We focus on classification among two HMMs that have the same language, which is the most difficult case to characterize; our approach can easily be applied to classification among any two arbitrary HMMs. The bound we obtain can also be used to approximate the dissimilarity between the two given HMMs.
{"title":"Bound on the probability of HMM misclassification","authors":"Christoforos Keroglou, C. Hadjicostis","doi":"10.1109/MED.2011.5983107","DOIUrl":"https://doi.org/10.1109/MED.2011.5983107","url":null,"abstract":"In this paper we consider the problem of classifying a sequence of observations among two known hidden Markov models (HMMs). We use a classifier that minimizes the probability of error (i.e., the probability of misclassification), and we are interested in assessing its performance by computing the a priori probability of error (before any observations are made). This probability (that the classifier makes an incorrect decision) can be obtained, as a function of the length of the sequence of observations, by summing up the probability of misclassification over all possible observation sequences, weighted by their corresponding probabilities. In an effort to avoid the high complexity associated with the computation of the exact probability of error, we establish an upper bound on the probability of error, and we find the necessary and sufficient conditions for this bound to tend to zero exponentially with the number of observation steps. We focus on classification among two HMMs that have the same language, which is the most difficult case to characterize; our approach can easily be applied to classification among any two arbitrary HMMs. The bound we obtain can also be used to approximate the dissimilarity between the two given HMMs.","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115758022","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 : 2011-06-20DOI: 10.1109/MED.2011.5983161
I. Djemili, A. Aitouche, V. Cocquempot
The problem is motivated by the need to guarantee high-performance engine behavior and in particular to respect the environmentally-based legislative regulations. The complexity of the intake systems of this type of engine makes this task particularly arduous and requires constantly monitoring and diagnosing the engine operation. First of all, a mean value model of a diesel engine subject to leakage in the intake manifold is presented and transformed into Takagi-Sugeno's model. Then, an adaptive observer for intake leakage estimation is developed. The proposed observer approach allows to estimate simultaneously the system states and a variable that is directly related to the presence of leakage. The diagnosis system is successfully evaluated using an advanced diesel engine professional simulator AMEsim(LMS).
{"title":"Adaptive observer for Intake leakage detection in diesel engines described by Takagi-Sugeno model","authors":"I. Djemili, A. Aitouche, V. Cocquempot","doi":"10.1109/MED.2011.5983161","DOIUrl":"https://doi.org/10.1109/MED.2011.5983161","url":null,"abstract":"The problem is motivated by the need to guarantee high-performance engine behavior and in particular to respect the environmentally-based legislative regulations. The complexity of the intake systems of this type of engine makes this task particularly arduous and requires constantly monitoring and diagnosing the engine operation. First of all, a mean value model of a diesel engine subject to leakage in the intake manifold is presented and transformed into Takagi-Sugeno's model. Then, an adaptive observer for intake leakage estimation is developed. The proposed observer approach allows to estimate simultaneously the system states and a variable that is directly related to the presence of leakage. The diagnosis system is successfully evaluated using an advanced diesel engine professional simulator AMEsim(LMS).","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114422638","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 : 2011-06-20DOI: 10.1109/MED.2011.5983214
N. Athanasopoulos, G. Bitsoris, L. Dritsas
In this note, the stability analysis and control design of Networked Control Systems (NCS) with bounded transmission delays, constant and unknown or time varying, is investigated using polyhedral Lyapunov functions. First, conditions guaranteeing stability are formulated for the equivalent augmented discrete-time system with structured uncertainties. Then, algebraic conditions leading to the computation of a linear state feedback controller for a NCS with bounded time varying delays are established. Both the stability analysis and synthesis problem are reduced to linear programming methods, a welcome consequence stemming from the choice of polyhedral Lyapunov functions.
{"title":"A polyhedral approach to the stability analysis and feedback stabilization of networked control systems","authors":"N. Athanasopoulos, G. Bitsoris, L. Dritsas","doi":"10.1109/MED.2011.5983214","DOIUrl":"https://doi.org/10.1109/MED.2011.5983214","url":null,"abstract":"In this note, the stability analysis and control design of Networked Control Systems (NCS) with bounded transmission delays, constant and unknown or time varying, is investigated using polyhedral Lyapunov functions. First, conditions guaranteeing stability are formulated for the equivalent augmented discrete-time system with structured uncertainties. Then, algebraic conditions leading to the computation of a linear state feedback controller for a NCS with bounded time varying delays are established. Both the stability analysis and synthesis problem are reduced to linear programming methods, a welcome consequence stemming from the choice of polyhedral Lyapunov functions.","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114604641","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 : 2011-06-20DOI: 10.1109/MED.2011.5983066
S. Theodoulis, I. Kitsios, L. Dritsas, A. Tzes, P. Wernert
The goal of this article is threefold: (1) Present a thorough model of a generic fin-guided projectile involving the 6DoF nonlinear dynamics, equilibrium point computation, Linear Parameter Varying (LPV) modeling & stability analysis concepts (2) Investigate various structures of low complexity closed loop feedback controllers that could be potentially applied to fin-guided projectile autopilots. (3) Investigate several crucial modeling issues relevant to autopilot design such as state space transformations which avoid output feedback in favor of state feedback, actuator model incorporation, etc. Simulation results demonstrate the performance and the complexity aspects of the proposed control algorithms.
{"title":"Autopilot strategies of guided projectiles for terminal guidance","authors":"S. Theodoulis, I. Kitsios, L. Dritsas, A. Tzes, P. Wernert","doi":"10.1109/MED.2011.5983066","DOIUrl":"https://doi.org/10.1109/MED.2011.5983066","url":null,"abstract":"The goal of this article is threefold: (1) Present a thorough model of a generic fin-guided projectile involving the 6DoF nonlinear dynamics, equilibrium point computation, Linear Parameter Varying (LPV) modeling & stability analysis concepts (2) Investigate various structures of low complexity closed loop feedback controllers that could be potentially applied to fin-guided projectile autopilots. (3) Investigate several crucial modeling issues relevant to autopilot design such as state space transformations which avoid output feedback in favor of state feedback, actuator model incorporation, etc. Simulation results demonstrate the performance and the complexity aspects of the proposed control algorithms.","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126654118","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 : 2011-06-20DOI: 10.1109/MED.2011.5983054
Mohamed Kara Mohamed, S. Patra, A. Lanzon
The wide range of applications and configurations of UAVs raises the need for different types of navigation methodologies compared to the conventional INS/GPS system. For instance, the limitation in cost, size and weight of indoor UAVs makes conventional navigation system unsuitable for these vehicles. In addition, the INS/GPS navigation system is impractical for indoor applications because the GPS signal is not reliable in closed territories. This paper proposes a new, cost-effective and simple indoor navigation system using three laser beams fixed to the body of the UAV and shooting to the ground. Then, a camera and computer vision algorithm are used to capture the laser dots on the ground and determine their coordinates. The position of laser dots is used to obtain full information about the position and orientation of the UAV. The proposed navigation system can be classified as a vision based navigation system, yet, it does not depend highly on the quality of the video shots taken from the vision camera and does not require a heavy image processing algorithm. An illustrative simulation study is conducted to demonstrate the validity of the proposed navigation system.
{"title":"Designing simple indoor navigation system for UAVs","authors":"Mohamed Kara Mohamed, S. Patra, A. Lanzon","doi":"10.1109/MED.2011.5983054","DOIUrl":"https://doi.org/10.1109/MED.2011.5983054","url":null,"abstract":"The wide range of applications and configurations of UAVs raises the need for different types of navigation methodologies compared to the conventional INS/GPS system. For instance, the limitation in cost, size and weight of indoor UAVs makes conventional navigation system unsuitable for these vehicles. In addition, the INS/GPS navigation system is impractical for indoor applications because the GPS signal is not reliable in closed territories. This paper proposes a new, cost-effective and simple indoor navigation system using three laser beams fixed to the body of the UAV and shooting to the ground. Then, a camera and computer vision algorithm are used to capture the laser dots on the ground and determine their coordinates. The position of laser dots is used to obtain full information about the position and orientation of the UAV. The proposed navigation system can be classified as a vision based navigation system, yet, it does not depend highly on the quality of the video shots taken from the vision camera and does not require a heavy image processing algorithm. An illustrative simulation study is conducted to demonstrate the validity of the proposed navigation system.","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126961370","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 : 2011-06-20DOI: 10.1109/MED.2011.5983183
Sandeep R. Kondaveeti, I. Izadi, Sirish L. Shah, Tongwen Chen
Alarm systems are an important complement to good control systems design. However alarm systems have not received the attention that they deserve and as a result they do not necessarily operate in the most reliable and efficient manner. Delay timers and latches are often used in the process industry to reduce alarm chatter and to minimize nuisance alarms. Effect of varying the size of on-delay, off-delay timers and latches on the accuracy of detection is discussed from a theoretical view point by modeling them using Markov chains. The performance of delay timers is compared to that of the latches. A design procedure for selecting the length of on-delay and off-delay timers based on historical alarm event data and the corresponding 'Return To Normal' (RTN) information is introduced and illustrated using a real industrial case study.
{"title":"On the use of delay timers and latches for efficient alarm design","authors":"Sandeep R. Kondaveeti, I. Izadi, Sirish L. Shah, Tongwen Chen","doi":"10.1109/MED.2011.5983183","DOIUrl":"https://doi.org/10.1109/MED.2011.5983183","url":null,"abstract":"Alarm systems are an important complement to good control systems design. However alarm systems have not received the attention that they deserve and as a result they do not necessarily operate in the most reliable and efficient manner. Delay timers and latches are often used in the process industry to reduce alarm chatter and to minimize nuisance alarms. Effect of varying the size of on-delay, off-delay timers and latches on the accuracy of detection is discussed from a theoretical view point by modeling them using Markov chains. The performance of delay timers is compared to that of the latches. A design procedure for selecting the length of on-delay and off-delay timers based on historical alarm event data and the corresponding 'Return To Normal' (RTN) information is introduced and illustrated using a real industrial case study.","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125909715","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 : 2011-06-20DOI: 10.1109/MED.2011.5982976
Vicente Diaz-Salas, R. Morales-Menéndez, R. Ramírez-Mendoza, O. Sename, L. Dugard
An MR damper is a device that exhibits a high nonlinear and complex behavior with a hysteresis phenomenon. A comparison between different state-of-the-art and a Linear Parameter Varying (LPV) models for Magneto-Rheological (MR) dampers is presented. Several experimental datasets validate that Linear Parameter Varying (LPV)-based model outperforms the classical MR damper models for 51 % than any structures considering the Error to Signal Ratio index and 37 % better considering the Squared root of Sum of Squared Errors index.
{"title":"LPV-based MR damper modelling","authors":"Vicente Diaz-Salas, R. Morales-Menéndez, R. Ramírez-Mendoza, O. Sename, L. Dugard","doi":"10.1109/MED.2011.5982976","DOIUrl":"https://doi.org/10.1109/MED.2011.5982976","url":null,"abstract":"An MR damper is a device that exhibits a high nonlinear and complex behavior with a hysteresis phenomenon. A comparison between different state-of-the-art and a Linear Parameter Varying (LPV) models for Magneto-Rheological (MR) dampers is presented. Several experimental datasets validate that Linear Parameter Varying (LPV)-based model outperforms the classical MR damper models for 51 % than any structures considering the Error to Signal Ratio index and 37 % better considering the Squared root of Sum of Squared Errors index.","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126827986","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 : 2011-06-20DOI: 10.1109/MED.2011.5983117
Romain Delpoux, T. Floquet
This article presents a parameter estimation algorithm for a magnetic bearing. Such process are inherently unstable systems with strongly nonlinear dynamics. Here, a simplified model of the magnetic bearing is developed. This enables to obtain a linear expression with respect to the unknown parameters. These parameters are measurable with difficulties, and may slightly vary over time. The expression of the estimates is written as a function of integrals of the inputs and outputs of the system. The simulations and the experiments show a fast and robust on-line identification.
{"title":"On-line parameter estimation of a magnetic bearing","authors":"Romain Delpoux, T. Floquet","doi":"10.1109/MED.2011.5983117","DOIUrl":"https://doi.org/10.1109/MED.2011.5983117","url":null,"abstract":"This article presents a parameter estimation algorithm for a magnetic bearing. Such process are inherently unstable systems with strongly nonlinear dynamics. Here, a simplified model of the magnetic bearing is developed. This enables to obtain a linear expression with respect to the unknown parameters. These parameters are measurable with difficulties, and may slightly vary over time. The expression of the estimates is written as a function of integrals of the inputs and outputs of the system. The simulations and the experiments show a fast and robust on-line identification.","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124914503","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 : 2011-06-20DOI: 10.1109/MED.2011.5983056
A. Pintea, Haoping Wang, N. Christov, P. Borne, D. Popescu, A. Badea
This paper proposes a MIMO linear quadratic regulator (LQR) controller designed for a horizontal variable speed wind turbine with focus on the operating range referring to the above rated wind speeds. The operating conditions of wind turbines make them subject to fluctuating loads that create fatigue and lead to damage. Alleviating these loads would reduce the needed materials, and increase the lifespan and the quality of the produced energy. The optimality of the entire system is defined in relation with the trade-off between the wind energy conversion maximization and the minimization of the fatigue in the mechanical structure. The solution of a control using an LQR regulator is presented. The performances of the optimal control are assessed and discussed by means of a set of simulations.
{"title":"Optimal control of variable speed wind turbines","authors":"A. Pintea, Haoping Wang, N. Christov, P. Borne, D. Popescu, A. Badea","doi":"10.1109/MED.2011.5983056","DOIUrl":"https://doi.org/10.1109/MED.2011.5983056","url":null,"abstract":"This paper proposes a MIMO linear quadratic regulator (LQR) controller designed for a horizontal variable speed wind turbine with focus on the operating range referring to the above rated wind speeds. The operating conditions of wind turbines make them subject to fluctuating loads that create fatigue and lead to damage. Alleviating these loads would reduce the needed materials, and increase the lifespan and the quality of the produced energy. The optimality of the entire system is defined in relation with the trade-off between the wind energy conversion maximization and the minimization of the fatigue in the mechanical structure. The solution of a control using an LQR regulator is presented. The performances of the optimal control are assessed and discussed by means of a set of simulations.","PeriodicalId":146203,"journal":{"name":"2011 19th Mediterranean Conference on Control & Automation (MED)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125162276","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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