Vibration isolation under isolator-structure interaction

This thesis analyses a general case of the vibration isolation (VI) problem, considering both a rigid and non-rigid supporting structures. The aim is to study changes on the behaviour of both systems isolators and supporting structure when the interaction phenomenon between them is considered. The influence of the VI task on the base response is evaluated. In addition, the effect of the base dynamics on the the VI and alignment problem is studied. The novel contribution to the knowledge of this thesis is formulation of a novel VI approach, which facilitates a holistic analysis of the problem considering all the systems involved on it. This approach is valid for any number of isolators and for any type of base structure. Moreover, different control objectives can be easily defined; evaluation of the interaction phenomenon on both the platform and base response for different VI techniques; demonstration of the importance of the isolator damping ratio on the influence that the VI task has on the base response; evaluation of the effects of the supporting structure dynamics on the VI and alignment problem when multiple isolators are involved; analysis of the Multiple-Input-Multiple-Ouput (MIMO) control strategy by comparison with the Single-Input-Single-Output (SISO) control strategy. This comparative has been made for the VI and alignment problem of multiple isolators on a non-rigid supporting structure and includes analysis of the effectiveness of the Coral Reefs Optimization algorithms to find nearly-optimal control gains in VI and alignment problems. Through the investigation made for this thesis, a number of significant results have been reached, which show the importance of the supporting structure dynamics on the VI and alignment task. Moreover, the interaction phenomenon, and its consequence on the base response, has been investigated experimentally. The results derived from this thesis conclude that, for most scenarios, the dynamics of the base affects the VI task. Also, the active VI (AVI) technique shows a greater influence on the base response than passive VI (PVI) technique, for most cases. It has been observed that the use of AVI technique can additionally be oriented to control vibrations of the supporting structure, while the VI task is developed. Significant differences have been found when multiple isolators are involved in the same task for the alignment and VI problem, depending on whether or not the dynamics of the base are considered. The best set of control gains for the rigid-support case (which lead to maximum damping ratio) differ from those obtained when the supporting structure is considered as a flexible system, for different cases analysed in this thesis. The MIMO control strategy has shown great improvement with respect to the use of the SISO control strategy. Also, the Coral Reefs Optimization algorithms have been demonstrated to be a suitable tool to find nearly-optimal solutions for this type of problems

Síndrome uña-rótula

Presentamos el estudio de 3 casos afectos de un síndrome "uña-rótula", con historia familiar positiva en uno de ellos. Este síndrome es un transtorno hereditario de transmisión autosómica dominante, caracterizado por displasia ungueal y de articulacione s y formación de una s excrecencia s óseas características a nive l del ilíaco (cuernos ilíacos). El síndrome completo se define por los cambios esqueléticos asociados a una nefropatía. Describimos las anomalías clínico-radiográficas de tres paciente s y realizamos una revisión de la literatura sobre esta displasia poco frecuente.The author s showed thre e patients affected by "nail patella" syndrome with positive familiar history in one case. The "nail patella" syndrome is an autosomal dominant condition, characterized by nail and joint dysplasia and extra bone formation at the os ilium. The complet e syndrome is characterized by a serie s of skeletal disorders and specific nephropathy. This article reports the clinical and roentgenographi c findings of three patients and the results of the study of their families. A review of the literature is done

A family of smooth controllers for swinging up a pendulum

Es el primer envío que hago. Le agradeceré si me confirma que es todo correcto, especialmente el cumplimiento de los derechos de propiedad de la editorial. Mi email es [email protected] paper presents a new family of controllers for swinging up a pendulum. The swinging up of the pendulum is derived from physical arguments based on two ideas: shaping the Hamiltonian for a system without damping; and providing damping or energy pumping in relevant regions of the state space. A family of simple smooth controllers without switches with nice properties is obtained. The main result is that all solutions that do not start at a zero Lebesgue measure set converge to the upright position for a wide range of the parameters in the control law. Thus, the swing-up and the stabilization problems are simultaneously solved with a single, smooth law. The properties of the solution can be modified by the parameters in the control law. Control signal saturation can also be taken into account using the Hamiltonian approach.MCyT-FEDER DPI2006-0733

soft robotic manipulation of onions and artichokes in the food industry

This paper presents the development of a robotic solution for a problem of fast manipulation and handling of onions or artichokes in the food industry. The complete solution consists of a parallel robotic manipulatior, a specially designed end-effector based on a customized vacuum suction cup, and a computer vision software developed for pick and place operations. First, the selection and design process of the proposed robotic solution to fit with the initial requeriments is presented, including the customized vacuum suction cup. Then, the kinematic analysis of the parallel manipulator needed to develop the robot control system is reviewed. Moreover, computer vision application is presented inthe paper. Hardware details of the implementation of the building prototype are also shown. Finally, conclusions and future work show the current status of the project

Antisymmetric-Tensor and Electromagnetic effects in an alpha'-non-perturbative Four-Dimensional String Cosmology

Starting from an exact (in the Regge slope alpha') functional method for a bosonic stringy sigma-model, we investigate four-dimensional cosmological string solutions in graviton, dilaton and antisymmetric tensor backgrounds, compatible with world-sheet conformal invariance, and valid beyond perturbative expansions in powers of alpha'. The antisymmetric tensor field, playing the role of an axion in the four-dimensional target space time, leads to spatial anisotropies of the emergent Robertson-Walker expanding Universe, and, upon coupling the system to the electromagnetic field, it results in non-trivial optical activity. Some estimates of the corresponding effects are made and their relevance to current cosmology is briefly discussed

On local CAC schemes for scalability of high-speed networks

This article has been extended from the original: “On local CAC schemes for scalability of high-speed networks” by the same authors, which was presented on the International Conference on Transparent Optical Networks (ICTON) held in Athens, Greece, on June 22-26, 2008Next generation networks are required to provide bandwidth on-demand for sessions with fine-time granularity. In this sense, centralized CAC (Connection Admission Control) approaches could suffer from scalability problems if the number of requests for connections is excessive. In this paper we investigate local CAC schemes where the admission decisions are performed at the network edges, based on precalculated admission quotas.The authors would like to acknowledge the BONE Network of Excellence, partially funded by the European Union Seventh Framework Programme, the MUSE project, partially funded by the EU Sixth FP, and the RUBENS project as part of the EUREKA CELTIC initiativ

Performance evaluation of an optical transparent access tier based on PON and spectral codes

The increasing amount of bandwidth requirements and quality of service needs for the next-generation access networks has boosted extensive research in the fiber-optics communication field. In this light, passive optical networks (PONs) combined with optical code division multiple access (OCDMA), provide a potentially cost-effective solution to meet such bandwidth demands. This work proposes an optical transparent architecture which enables all-optical communication between the network nodes. The encoded data streams are multiplexed at a merging point which results in multiple user interference (MUI), thus significantly reducing the network throughput. The networking nodes are able to monitor and record user activity in the PON, and further register the (past) state of activity at the merging point. In this work, we study the coherence of state between the networking nodes and the merging point, for different packet size distributions, in order to predict an optimal transmission instant of each node's data packets. We note that the states are coherent depending on the packet size distribution

Auto-adaptative Robot-aided Therapy based in 3D Virtual Tasks controlled by a Supervised and Dynamic Neuro-Fuzzy System

This paper presents an application formed by a classification method based on the architecture of ART neural network (Adaptive Resonance Theory) and the Fuzzy Set Theory to classify physiological reactions in order to automatically and dynamically adapt a robot-assisted rehabilitation therapy to the patient needs, using a three-dimensional task in a virtual reality system. Firstly, the mathematical and structural model of the neuro-fuzzy classification method is described together with the signal and training data acquisition. Then, the virtual designed task with physics behavior and its development procedure are explained. Finally, the general architecture of the experimentation for the auto-adaptive therapy is presented using the classification method with the virtual reality exercise