Fuzzy, integer and fractional-order control: application on a wind turbine benchmark model

This paper presents a comparison between proportional integral control approaches for variable speed wind turbines. Integer and fractional-order controllers are designed using linearized wind turbine model whilst fuzzy controller also takes into account system nonlinearities. These controllers operate in the full load region and the main objective is to extract maximum power from the wind turbine while ensuring the performance and reliability required to be integrated into an electric grid. The main contribution focuses on the use of fractional-order proportional integral (FOPI) controller which benefits from the introduction of one more tuning parameter, the integral fractional-order, taking advantage over integer order proportional integral (PI) controller. A comparison between proposed control approaches for the variable speed wind turbines is presented using a wind turbine benchmark model in the Matlab/Simulink environment. Results show that FOPI has improved system performance when compared with classical PI and fuzzy PI controller outperforms the integer and fractional-order control due to its capability to deal with system nonlinearities and uncertainties. © 2014 IEEE.

SENSITIVITY ANALYSIS OF TRACK VIBRATIONS DUE TO VERTICAL STIFFNESS VARIATION IN HIGH-SPEED RAILWAYS

High speed trains, when crossing regions with abrupt changes in vertical stiffness of the track and/or subsoil, may generate excessive ground and track vibrations. There is an urgent need for specific analyses of this problem so as to allow reliable esimates of vibration amplitude. Full understanding of these phenomena will lead to new construction solutions and mitigation of undesirable features. In this paper analytical transient solutions of dynamic response of one-dimensional systems with sudden change of foundation stiffness are derived. Results are expressed in terms of vertical displacement. Sensitivity analysis of the response amplitude is also performed. The analytical expressions presented herein, to the authors’ knowledge, have not been published yet. Although related to one-dimensional cases, they can give useful insight into the problem. Nevertheless, in order to obtain realistic response, vehicle- rail interaction cannot be omitted. Results and conclusions are confirmed using general purpose commercial software ANSYS. In conclusion, this work contributes to a better understanding of the additional vibration phenomenon due to vertical stiffness variation, permitting better control of the train velocity and optimization of the track design.

New analytical methodologies for doping control – detection of anabolic androgenic steroids in human urine

Dissertation submitted to Faculdade de Ciências e Tecnologia - Universidade Nova de Lisboa in fulfilment of the requirements for the degree of Doctor of Philosophy (Biochemistry - Biotechnology)

eVentos 2 - Autonomous sailboat control

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

Mechanical external work and recovery at preferred walking speed in obese subjects

PURPOSE: The aim of this study was to compare the mechanical external work (per kg) and pendular energy transduction at preferred walking speed (PWS) in obese versus normal body mass subjects to investigate whether obese adults adopt energy conserving gait mechanics. METHODS: The mechanical external work (Wext) and the fraction of mechanical energy recovered by the pendular mechanism (Rstep) were computed using kinematic data acquired by an optoelectronic system and were compared in 30 obese (OG; body mass index [BMI] = 39.6 +/- 0.6 kg m(-2); 29.5 +/- 1.3 yr) and 19 normal body mass adults (NG; BMI = 21.4 +/- 0.5 kg m(-2); 31.2 +/- 1.2 yr) walking at PWS. RESULTS: PWS was significantly lower in OG (1.18 +/- 0.02 m s(-1)) than in NG (1.33 +/- 0.02 m s(-1); P <or= 0.001). There was no significant difference in Wext per unit mass between groups (OG: 0.36 +/- 0.03 J kg(-1) m(-1); NG: 0.31 +/- 0.02 J kg(-1) m(-1); P = 0.12). Rstep was significantly lower in OG (68.4% +/- 2.0%) compared with NG (74.4% +/- 1.0%; P = 0.01). In OG only, Wext per unit mass was positively correlated with PWS (r = 0.57; P < 0.001). CONCLUSION: Obese adults do not appear to alter their gait to improve pendular energy transduction and may select slower PWS to reduce mechanical and metabolic work.

Predictive and distributed routing balancing (PR-DRB): high speed interconnection networks

Current parallel applications running on clusters require the use of an interconnection network to perform communications among all computing nodes available. Imbalance of communications can produce network congestion, reducing throughput and increasing latency, degrading the overall system performance. On the other hand, parallel applications running on these networks posses representative stages which allow their characterization, as well as repetitive behavior that can be identified on the basis of this characterization. This work presents the Predictive and Distributed Routing Balancing (PR-DRB), a new method developed to gradually control network congestion, based on paths expansion, traffic distribution and effective traffic load, in order to maintain low latency values. PR-DRB monitors messages latencies on intermediate routers, makes decisions about alternative paths and record communication pattern information encountered during congestion situation. Based on the concept of applications repetitiveness, best solution recorded are reapplied when saved communication pattern re-appears. Traffic congestion experiments were conducted in order to evaluate the performance of the method, and improvements were observed.

Experimental Modeling and Control Strategies on an Open Mobile Robot Platform PRIM

This research work deals with the problem of modeling and design of low level speed controller for the mobile robot PRIM. The main objective is to develop an effective educational tool. On one hand, the interests in using the open mobile platform PRIM consist in integrating several highly related subjects to the automatic control theory in an educational context, by embracing the subjects of communications, signal processing, sensor fusion and hardware design, amongst others. On the other hand, the idea is to implement useful navigation strategies such that the robot can be served as a mobile multimedia information point. It is in this context, when navigation strategies are oriented to goal achievement, that a local model predictive control is attained. Hence, such studies are presented as a very interesting control strategy in order to develop the future capabilities of the system

Implementation of zonal control algorithms in adaptive optical systems with sparse control matrices

Miralls deformables més i més grans, amb cada cop més actuadors estan sent utilitzats actualment en aplicacions d'òptica adaptativa. El control dels miralls amb centenars d'actuadors és un tema de gran interès, ja que les tècniques de control clàssiques basades en la seudoinversa de la matriu de control del sistema es tornen massa lentes quan es tracta de matrius de dimensions tan grans. En aquesta tesi doctoral es proposa un mètode per l'acceleració i la paral.lelitzacó dels algoritmes de control d'aquests miralls, a través de l'aplicació d'una tècnica de control basada en la reducció a zero del components més petits de la matriu de control (sparsification), seguida de l'optimització de l'ordenació dels accionadors de comandament atenent d'acord a la forma de la matriu, i finalment de la seva posterior divisió en petits blocs tridiagonals. Aquests blocs són molt més petits i més fàcils de fer servir en els càlculs, el que permet velocitats de càlcul molt superiors per l'eliminació dels components nuls en la matriu de control. A més, aquest enfocament permet la paral.lelització del càlcul, donant una com0onent de velocitat addicional al sistema. Fins i tot sense paral. lelització, s'ha obtingut un augment de gairebé un 40% de la velocitat de convergència dels miralls amb només 37 actuadors, mitjançant la tècnica proposada. Per validar això, s'ha implementat un muntatge experimental nou complet , que inclou un modulador de fase programable per a la generació de turbulència mitjançant pantalles de fase, i s'ha desenvolupat un model complert del bucle de control per investigar el rendiment de l'algorisme proposat. Els resultats, tant en la simulació com experimentalment, mostren l'equivalència total en els valors de desviació després de la compensació dels diferents tipus d'aberracions per als diferents algoritmes utilitzats, encara que el mètode proposat aquí permet una càrrega computacional molt menor. El procediment s'espera que sigui molt exitós quan s'aplica a miralls molt grans.

Neuroplasticity of inhibitory control

Executive control refers to a set of abilities enabling us to plan, control and implement our behavior to rapidly and flexibly adapt to environmental requirements. These adaptations notably involve the suppression of intended or ongoing cognitive or motor processes, a skill referred to as "inhibitory control". To implement efficient executive control of behavior, one must monitor our performance following errors to adjust our behavior accordingly. Deficits in inhibitory control have been associated with the emergènce of a wide range of psychiatric disorders, ranging from drug addiction to attention deficit/hyperactivity disorders. Inhibitory control deficits could, however, be remediated- The brain has indeed the amazing possibility to reorganize following training to allow for behavioral improvements. This mechanism is referred to as neural and behavioral plasticity. Here, our aim is to investigate training-induced plasticity in inhibitory control and propose a model of inhibitory control explaining the spatio- temporal brain mechanisms supporting inhibitory control processes and their plasticity. In the two studies entitled "Brain dynamics underlying training-induced improvement in suppressing inappropriate action" (Manuel et al., 2010) and "Training-induced neuroplastic reinforcement óf top-down inhibitory control" (Manuel et al., 2012c), we investigated the neurophysiological and behavioral changes induced by inhibitory control training with two different tasks and populations of healthy participants. We report that different inhibitory control training developed either automatic/bottom-up inhibition in parietal areas or reinforced controlled/top-down inhibitory control in frontal brain regions. We discuss the results of both studies in the light of a model of fronto-basal inhibition processes. In "Spatio-temporal brain dynamics mediating post-error behavioral adjustments" (Manuel et al., 2012a), we investigated how error detection modulates the processing of following stimuli and in turn impact behavior. We showed that during early integration of stimuli, the activity of prefrontal and parietal areas is modulated according to previous performance and impacts the post-error behavioral adjustments. We discuss these results in terms of a shift from an automatic to a controlled form of inhibition induced by the detection of errors, which in turn influenced response speed. In "Inter- and intra-hemispheric dissociations in ideomotor apraxia: a large-scale lesion- symptom mapping study in subacute brain-damaged patients" (Manuel et al., 2012b), we investigated ideomotor apraxia, a deficit in performing pantomime gestures of object use, and identified the anatomical correlates of distinct ideomotor apraxia error types in 150 subacute brain-damaged patients. Our results reveal a left intra-hemispheric dissociation for different pantomime error types, but with an unspecific role for inferior frontal areas. Les fonctions exécutives désignent un ensemble de processus nous permettant de planifier et contrôler notre comportement afin de nous adapter de manière rapide et flexible à l'environnement. L'une des manières de s'adapter consiste à arrêter un processus cognitif ou moteur en cours ; le contrôle de l'inhibition. Afin que le contrôle exécutif soit optimal il est nécessaire d'ajuster notre comportement après avoir fait des erreurs. Les déficits du contrôle de l'inhibition sont à l'origine de divers troubles psychiatriques tels que l'addiction à la drogue ou les déficits d'attention et d'hyperactivité. De tels déficits pourraient être réhabilités. En effet, le cerveau a l'incroyable capacité de se réorganiser après un entraînement et ainsi engendrer des améliorations comportementales. Ce mécanisme s'appelle la plasticité neuronale et comportementale. Ici, notre but èst d'étudier la plasticité du contrôle de l'inhibition après un bref entraînement et de proposer un modèle du contrôle de l'inhibition qui permette d'expliquer les mécanismes cérébraux spatiaux-temporels sous-tendant l'amélioration du contrôle de l'inhibition et de leur plasticité. Dans les deux études intitulées "Brain dynamics underlying training-induced improvement in suppressing inappropriate action" (Manuel et al., 2010) et "Training-induced neuroplastic reinforcement of top-down inhibitory control" (Manuel et al., 2012c), nous nous sommes intéressés aux changements neurophysiologiques et comportementaux liés à un entraînement du contrôle de l'inhibition. Pour ce faire, nous avons étudié l'inhibition à l'aide de deux différentes tâches et deux populations de sujets sains. Nous avons démontré que différents entraînements pouvaient soit développer une inhibition automatique/bottom-up dans les aires pariétales soit renforcer une inhibition contrôlée/top-down dans les aires frontales. Nous discutons ces résultats dans le contexte du modèle fronto-basal du contrôle de l'inhibition. Dans "Spatio-temporal brain dynamics mediating post-error behavioral adjustments" (Manuel et al., 2012a), nous avons investigué comment la détection d'erreurs influençait le traitement du prochain stimulus et comment elle agissait sur le comportement post-erreur. Nous avons montré que pendant l'intégration précoce des stimuli, l'activité des aires préfrontales et pariétales était modulée en fonction de la performance précédente et avait un impact sur les ajustements post-erreur. Nous proposons que la détection d'erreur ait induit un « shift » d'un mode d'inhibition automatique à un mode contrôlé qui a à son tour influencé le temps de réponse. Dans "Inter- and intra-hemispheric dissociations in ideomotor apraxia: a large-scale lesion-symptom mapping study in subacute brain-damaged patients" (Manuel et al., 2012b), nous avons examiné l'apraxie idémotrice, une incapacité à exécuter des gestes d'utilisation d'objets, chez 150 patients cérébro-lésés. Nous avons mis en avant une dissociation intra-hémisphérique pour différents types d'erreurs avec un rôle non spécifique pour les aires frontales inférieures.

Guidleines for Removal of Traffic Control Devices in Rural Areas, October 2005

It is commonly regarded that the overuse of traffic control devices desensitizes drivers and leads to disrespect, especially for low-volume secondary roads with limited enforcement. The maintenance of traffic signs is also a tort liability concern, exacerbated by unnecessary signs. The Federal Highway Administration’s (FHWA) Manual on Uniform Traffic Control Devices (MUTCD) and the Institute of Transportation Engineer’s (ITE) Traffic Control Devices Handbook provide guidance for the implementation of STOP signs based on expected compliance with right-of-way rules, provision of through traffic flow, context (proximity to other controlled intersections), speed, sight distance, and crash history. The approach(es) to stop is left to engineering judgment and is usually dependent on traffic volume or functional class/continuity of system. Although presently being considered by the National Committee on Traffic Control Devices, traffic volume itself is not given as a criterion for implementation in the MUTCD. STOP signs have been installed at many locations for various reasons which no longer (or perhaps never) met engineering needs. If in fact the presence of STOP signs does not increase safety, removal should be considered. To date, however, no guidance exists for the removal of STOP signs at two-way stop-controlled intersections. The scope of this research is ultra-low-volume (< 150 daily entering vehicles) unpaved intersections in rural agricultural areas of Iowa, where each of the 99 counties may have as many as 300 or more STOP sign pairs. Overall safety performance is examined as a function of a county excessive use factor, developed specifically for this study and based on various volume ranges and terrain as a proxy for sight distance. Four conclusions are supported: (1) there is no statistical difference in the safety performance of ultra-low-volume stop-controlled and uncontrolled intersections for all drivers or for younger and older drivers (although interestingly, older drivers are underrepresented at both types of intersections); (2) compliance with stop control (as indicated by crash performance) does not appear to be affected by the use or excessive use of STOP signs, even when adjusted for volume and a sight distance proxy; (3) crash performance does not appear to be improved by the liberal use of stop control; (4) safety performance of uncontrolled intersections appears to decline relative to stop-controlled intersections above about 150 daily entering vehicles. Subject to adequate sight distance, traffic professionals may wish to consider removal of control below this threshold. The report concludes with a section on methods and legal considerations for safe removal of stop control.

Control d'un sistema de marcatge làser de caixes

RESUM Avui en dia, l’alta competitivitat que existeix al mercat, fa que les empreses hagin d’esprémer al màxim les seves possibilitats per no quedar-se enrere. Un dels processos en que aquest fet hi és més present és el productiu. L’empresa JCM Technologies també engloba aquest camp i és en un dels seus processos productius on aquest projecte pren part. L’objectiu d’aquest projecte final de carrera ha estat desenvolupar un sistema per poder marcar caixes mitjançant un làser de CO2 i un automatisme manipulador de caixes. D’aquesta manera aquest procés productiu té una durada molt inferior a l’antic procés, que consistia en enganxar una etiqueta al lloc on ara és marcat pel làser. Per satisfer els objectius, s’ha creat una aplicació de Windows que per mitjà d’una interfície gràfica, permet a l’usuari realitzar els passos necessaris per fer el marcatge. Primerament es recullen les dades procedents de la comanda; seguidament es seleccionen les que s’han de marcar a les caixes i s’envien al làser mitjançant comunicació sèrie; una vegada aquesta inicialització ha finalitzat correctament, s’engega la seqüència de marcatge de les caixes, que en marcarà la quantitat indicada. Aquest procés de marcatge consisteix en supervisar l’estat en que es troben certes senyals, procedents de l’automatisme i del làser, i depenent d’aquestes generar-ne unes altres. Aconseguint així realitzar el procés de marcatge de cada caixa. Com a conclusions cal dir, que els objectius s’han complert, ja que s’ha aconseguit un procés de marcatge ràpid i robust. També s’ha aconseguit que les parts de configuració de l’aplicació, i de les caixes siguin de fàcil manipulació. Per tant, amb l’acompliment dels objectius d’aquest projecte, aconseguim completar el sistema de marcatge, i permetre que les caixes siguin marcades de forma correcta, ràpida i eficient.

Control d'una bobinadora automàtica

Un dels problemes típics de regulació en el camp de l’automatització industrial és el control de velocitat lineal d’entrada del fil a les bobines, ja que com més gruix acumulem a igual velocitat de rotació de la bobina s’augmenta notablement la velocitat lineal d’entrada del fil, aquest desajust s’ha de poder compensar de forma automàtica per aconseguir una velocitat d’entrada constant. Aquest problema de regulació de velocitats és molt freqüent i de difícil control a la indústria on intervé el bobinat d’algun tipus de material com cablejat, fil, paper, làmines de planxa, tubs, etc... Els dos reptes i objectius principals són, primer, la regulació de la velocitat de rotació de la bobina per aconseguir una velocitat lineal del fil d’entrada, i segon, mitjançant el guiatge de l’alimentació de fil a la bobina, aconseguir un repartiment uniforme de cada capa de fil. El desenvolupament consisteix amb l’automatització i control d’una bobinadora automàtica mitjançant la configuració i programació de PLC’s, servomotors i encoders. Finalment es farà el muntatge pràctic sobre una bancada per verificar i simular el seu correcte funcionament que ha de donar solució a aquests problemes de regulació de velocitats. Com a conclusions finals s’han aconseguit els objectius i una metodologia per fer una regulació de velocitats de rotació per bobines, amb accionaments de servomotors amb polsos, i a nivell de coneixements he aconseguit dominar les aplicacions d’aquest tipus d’accionaments aplicats a construccions mecàniques.

Speed Management Toolbox for Rural Communities, TR-630, 2012

The primary objective of this toolbox is to summarize various known traffic-calming treatments and their effectiveness. This toolbox focuses on roadway-based treatments for speed management, particularly for rural communities with transition zones. Education, enforcement, and policy strategies should also be considered, but are not the focus of this toolbox. The research team identified treatments based on their own research, a review of the literature, and discussion with other professionals. This toolbox describes each treatment and summarizes placement, advantages, disadvantages, effectiveness, appropriateness, and cost for each treatment. The categories of treatments covered in this toolbox are as follows: horizontal physical displacement, vertical physical displacement, narrowing, surroundings, pavement markings, traffic control signs, and other strategies. Separate 3- to 4-page Tech Briefs for various aspects of this toolbox are attached to this record: Center Islands with Raised Curbing for Rural Traffic Calming, Colored Entrance Treatments for Rural Traffic Calming, Dynamic Speed Feedback Signs for Rural Traffic Calming, Transverse Speed Bars for Rural Traffic Calming. This toolbox and the tech briefs are related to the report Evaluation of Low Cost Traffic Calming for Rural Communities – Phase II, which is also included in this record or can be found at http://publications.iowa.gov/id/eprint/14769

Liability and Traffic Control Considerations for Low Water Stream Crossings, HR-218, 1981

The current shortage of highway funds precludes the immediate replacement of most of the bridges that have been evaluated as structurally deficient or functionally obsolete or both. A low water stream crossing (LWSC) affords an economical alternative to the replacement of a bridge with another bridge in many instances. However, the potential liability that might be incurred from the use of LWSCs has served as a deterrent to their use. Nor have guidelines for traffic control devices been developed for specific application to LWSCs. This research addressed the problems of liability and traffic control associated with the use of LWSCs. Input to the findings from this research was provided by several persons contacted by telephone plus 189 persons who responded to a questionnaire concerning their experience with LWSCs. It was concluded from this research that a significant potential for accidents and liability claims could result from the use of LWSCs. However, it was also concluded that this liability could be reduced to within acceptable limits if adequate warning of the presence of an LWSC were afforded to road users. The potential for accidents and liability could further be reduced if vehicular passage over an LWSC were precluded during periods when the road was flooded. Under these conditions, it is believed, the potential for liability from the use of an LWSC on an unpaved, rural road would be even less than that resulting from the continuing use of an inadequate bridge. The signs recommended for use in advance of an LWSC include two warning signs and one regulatory sign with legends as follows: FLOOD AREA AHEAD, IMPASSABLE DURING HIGH WATER, DO NOT ENTER WHEN FLOODED. Use of the regulatory sign would require an appropriate resolution by the Board of Supervisors having responsibility for a county road. Other recommendations include the optional use of either a supple mental distance advisory plate or an advisory speed plate, or both, under circumstances where these may be needed. It was also recommended HR-218 Liability & Traffic Control Considerations for Low Water Stream Crossings that LWSCs be used only on unpaved roads and that they not be used in locations where flooding of an LWSC would deprive dwelling places of emergency ground access.