Energy Shaping Control of an Inverted Flexible Pendulum Fixed to a Cart

Control of compliant mechanical systems is increasingly being researched for several applications including flexible link robots and ultra-precision positioning systems. The control problem in these systems is challenging, especially with gravity coupling and large deformations, because of inherent underactuation and the combination of lumped and distributed parameters of a nonlinear system. In this paper we consider an ultra-flexible inverted pendulum on a cart and propose a new nonlinear energy shaping controller to keep the pendulum at the upward position with the cart stopped at a desired location. The design is based on a model, obtained via the constrained Lagrange formulation, which previously has been validated experimentally. The controller design consists of a partial feedback linearization step followed by a standard PID controller acting on two passive outputs. Boundedness of all signals and (local) asymptotic stability of the desired equilibrium is theoretically established. Simulations and experimental evidence assess the performance of the proposed controller.Comment: 11 pages, 7 figures, extended version of the NOLCOS 2016 pape

Nous materials procedents de la Cova Santa de la Font de la Figuera

Estudi de materials ceràmics de l'Horitzó Camapniforme de Transició i de l'Edat del Bronze

Interconnection and Damping Assignment Passivity-Based Control Without Partial Differential Equations

Interconnection and damping assignment (IDA) is a popular passivity-based control (PBC) technique. This nonlinear control approach has proven suitable for stabilizing a wide range of systems. However, like many other nonlinear control techniques, implementing the IDA-PBC approach is often hampered by the necessity of solving partial differential equations (PDEs). This paper studies systems for which the solutions to these equations are always guaranteed, and closed-form solutions are known. To this end, we provide straightforwardly verifiable conditions over the open-loop system such that IDA-PBC can be applied without solving PDEs

La Cova dels Diablets (Alcalà de Xivert, Castelló). Prehistòria a la Serra d’ Irta

El llibre presenta les excavacions i tots els materials arqueològics coneguts de la Cova dels Diablets a Alcalà de Xivert, una cavitat amb una seqüència d'ocupació humana que s'inicia fa més de 10.000 anys i finalitza al tercer mil•lenni abans de l'era, documentant-s’hi també visites o usos posteriors en època històrica. Amb la participació de diversos especialistes que analitzen cadascun dels aspectes de les ocupacions prehistòriques, es presta especial atenció a un vas ceràmic decorat amb impressions i incisions del neolític antic, especialment interessant dins del registre material de la cova

New ceramic fragments from La Cova de la Sarsa (Bocairent, Valencia) belonging to the Ponsell Collection of the Alcoi Municipal Archaeological Museum

Presentem un petit lot de ceràmiques seleccionades que van ser recuperades en les excavacions realitzades per Fernando Ponsell a la Cova de la Sarsa (Bocairent, València), tornades fa poc al Museu Arqueològic Municipal d’Alcoi després de ser estudiades per M. D. Asquerino. Es tracta d’un conjunt típic del Neolític Antic Cardial. Finalment, assenyalem de forma breu algunes de les problemàtiques en què actualment queda enquadrada la cova en el context del Neolític antic local. Paraules clau: Ceràmica, Cova de la Sarsa, Neolític Antic, Fernando Ponsell.In this paper, the study of a small ceramics collection from Cova de la Sarsa (Bocairent, fieldwork campaign carried out by Fernando Ponsell, studied first by M.D. Asquerino, The lot in question is a typical assemblage from the Cardial ancient Neolithic. Furthermore, involving the local ancient Neolithic are specified. Key words: ceramics, Cova de la Sarsa, ancient Neolithic, Fernando Ponsell.Presentamos un pequeño lote de cerámicas seleccionadas que fueron recuperadas en las excavaciones realizadas por Fernando Ponsell en la Cova de la Sarsa (Bocairent, Valencia), recientemente devuelto al Museu Arqueològic Municipal d’Alcoi tras ser estudiado por M. D. Asquerino. Se trata de un conjunto típico del Neolítico Antiguo Cardial. Finalmente, señalamos de forma breve algunas de las problemáticas en las que actualmente queda encuadrada la cueva en el contexto del Neolítico antiguo local. Palabras clave: Cerámica, Cova de la Sarsa, Neolítico Antiguo, Fernando Ponsell

Origin and role of neural signatures in bursting neurons

Copyright 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.A traditional view in neuroscience is that information arriving through one channel, i.e. a synapse, is encoded through a single code in the signal, e.g., the rate or the precise timing of the incoming events. However, not all the neural readers have to be interested in the same aspect of a common input signal, especially in multifunctional networks that can take advantage of several simultaneous codes. Multiple codes can be used to discriminate or contextualize certain inputs, even in single neurons. Dynamical mechanisms can add to the existing hard-wired connectivity for this task. Recent experiments have revealed the existence of neural signatures in the activity of bursting cells of invertebrate central pattern generators. These signatures consist of cell-specific spike timings in the bursting activity of the neurons. The signatures coexist with the information encoded in the frequency and/or phase relationships of the slow waves. The functional role of these neural fingerprints is still unclear. Based on experiments and using conductance-based models, we discuss the origin and the role of neural signatures as a part of a multicoding strategy for single cells in different types of neural circuits.This work was supported by Fundacion BBVA, MEC BFU2006-07902/BFI and MEC TIN2004-04363-C03-03

Effect of individual spiking activity on rhythm generation of central pattern generators

This is the author’s version of a work that was accepted for publication in Neurocomputing. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Neurocomputing 58-60 (2004):10.1016/j.neucom.2004.01.091Central Pattern Generators (CPGs) are highly specialized neural networks often with redundant elements that allow the system to act properly in case of error. CPGs are multifunctional circuits, i.e. the same CPG can produce many di®erent rhythms in response to modulatory or sensory inputs. All these rhythms have to be optimal for motor control and coordination. In this paper, we use a model of the well-known pyloric CPG of crustacean to analyze the importance of redundant connections and individual spiking activity in the generation of the CPG rhythm. In particular, we study the e®ect of di®erent spike distributions of a neuron on the collective behavior of the CPG.This work was supported by the Spanish MCyT (BFI-2000- 0157 and TIC 2002-572-C02-02

On-line characterization of transient neuronal activity

Paper presented firstly in a poster at the IV International Conference Net-Works 2011 Complex Networks: Structure, Applications and Related Topics, held in El Escorial (Spain) on October 26th-28th, 2011Characterization and control of nonlinear and non-stationary pro- cesses is an active topic in the field of the applied theory of dynamical systems. In this context classical control techniques cannot be applied straightforward, and thus observation and actuation should be properly incorporated into a real-time feedback (or closed-loop) methodology. One of the possible application scenarios of this methodology is depicted by neural activity. In this work we analyze the problem related to the first component of the real-time closed-loop technology for the case of neural activity. This being the case, be discuss different methods to classify dynamics and to detect events in a automatic and fast way.This work was supported by MICINN BFU2009-08473 and TIN-2010-19607