Control design for energy saving

International audienceThis paper presents the interest of including control strategy into electropneumatic design. For this certain experimental results obtained in an electropneumatic process have been presented. Using two servo-distributors leads to a system with one degree of freedom. This opportunity is exploited for in two objectives. The first concerns positioning control and the second attempts to optimise energy efficiency. With this aim an energy optimisation algorithm has been presented. The chosen control algorithm issues from the flatness concept. KEY WORDS nonlinear control, flatness, energy saving, electropneumatic

Music production-consumption and the service-good spectrum under the sway of a shift within a shift

Nowadays music constitutes a phenomenon whose complexion entangles aspects simultaneously related to society, culture, art, business, and technology. Due to the combined influence of these aspects, music production-consumption acquires some unique features. Added to that, the swift evolution and growing influence of the economic-technological association have increasingly affected music as a sociocultural phenomenon, as an art form, and as a corporative business, increasing the complexity of an already convoluted context. Given the composite and dynamic constitution of the music field, the present approach departs from a multidisciplinary analysis, establishing a methodological groundwork that comprehends conceptual and qualitative research, elaborated through exploratory study. Under a standard economic perspective, music production-consumption belongs in the structure of the music supply chain, presenting a rather uncertain status between service and good. Apart from the economic understanding, however, music comprises a wide variety of manifestations, which do not suit conventional production-consumption processes. In order to cope with the inexorable duality of this paradoxical coexistence, this study proposes a model intended to contribute to the building of a comprehensive knowledge on music production and consumption. As this model departs from some specific flows of music production and consumption, it creates an array of patterns, pinpointing their situation within the service-good spectrum. In addition, it considers Digital Revolution and globalized communications as enablers that affect the foundations of traditional music, unbalance routine flows inside the supply chain of the music industry and cause music production-consumption relationships to shift their status from product-oriented to service-oriented

Hybrid control for switching between position and force tracking

International audienceThis paper is the logical result of previous researches about advanced control in electropneumatic systems. After different works in feedback control of electropneumatic actuators in position tracking [1] or in force tracking [2], this study led about a method to switch between these two different focuses. This question is an important problem in many industrial systems, for example in the case of vehicle active suspension or for pneumatic or hydraulic pliers, fingers and spot welding, fatigue test. Indeed, some dangerous damages could occur when the aim is to move a load near a structure and to apply a force against this structure. The major difficulty is to know when and how to switch between the position control and the force control (this is here the notion of hybrid control). A classical occurrence is due to a static position error when the control algorithm switches from position feedback to force feedback. The result leads very often to an undesirable impact to the structure. KEYWORDS Force / position tracking, hybrid control, pneumatic

Pressure regulator stability analysis in electropneumatic

International audienceThis paper aims at giving a analytical approach of the stability analysis of control pressure components in pneumatic domain. Some authors have given some results in linear case especially in the hydraulic context [Meritt 1960, Mac Cloy et al 1980, Margolis 1997, Alirand et al. 2002]. The structure and the technologies of commonly used pneumatic pressure control component are firstly introduced, and then a non-linear model is proposed as the basis for the stability analysis. The classical linear method, based on the tangent linearized model is applied to determine the analytical stability conditions using Routh-Hurwitz criteria. The root loci are finally studied according to a set of equilibrium points which corresponds to various conditions of use. In this last part, an existing pressure regulator is used as an example and allows the development of an analysis concerning the dynamic performances on realistic basis. To conclude, the proposed approach gives a set of design rules which enables the system parameters to be sized according to the required dynamic performances and stability

Bicausality-based Procedures for Transfer and Transmission Matrix Determination of Single Source Single Load Linear Systems

International audienceIn linear SISO systems the energy flows from the source to the load through each actuating power line. Bond graph representation is well suited for studying the energy transfer in these systems because, in most of the systems, we can consider that energy flows through a power line embedded in two-port subsystems. Moreover, with bond graph language, we benefit from the ease of analytical exploitation introduced by the calculus causality and bicausality concepts.In the bond graph representation of a system the power in some port is associated to a power bond to which two power variables are attached. The determination of the transmission matrix linking two power variables is an efficient tool for studying the energy transfer. Furthermore it is often useful to study the bi-directional energy transfer i.e. from the source to the load and vice versa. The latter case (namely from the load to the source) is quite useful for the energy sizing of asystem from its dynamic specifications on an output variable.This paper proposes different procedures for determining direct and inverse transmission matrices and the transfer matrix between an internal bond and an environmental one for Single Source Single Load Linear systems represented by bond graphs. The procedures are based on the bicausality concept and the loop rule

Accounting for sizing parameters and boundary geometry in the bond graph representation of energetic elements

International audienceIn this paper we present how to take into account parameters and variables that were not initially present in the bond graph representation of some components. These bond graph considerations are justified mainly by design arguments but from the automatics point of view this is closely related to the state representation concept. We present this idea through the examples of a mechanical spring and a simple thermodynamic system. In each case one solution is to substitute a multiport energy storage element to the initial one port element. It emphasizes the close relationship between the order of this component and the output variables that we want to observe in this component

Strangeness S=−2S=-2 baryon-baryon interactions in relativistic chiral effective field theory

We study the strangeness $S=-2$ baryon-baryon interactions in relativistic chiral effective field theory at leading order. Among the 15 relevant low energy constants, eight of them are determined by fitting to the state of the art lattice QCD data of the HAL QCD Collaboration (with $m_\pi=146$ MeV), and the rest are either taken from the study of the $S=-1$ hyperon-nucleon systems, assuming strict SU(3) flavor symmetry, or temporarily set equal to zero. Using the so-obtained low energy constants, we extrapolate the results to the physical point, and show that they are consistent with the available experimental scattering data. Furthermore, we demonstrate that the $\Lambda\Lambda$ and $\Xi N$ phase shifts near the $\Xi N$ threshold are very sensitive to the lattice QCD data fitted, to the pion mass, and to isospin symmetry breaking effects. As a result, any conclusion drawn from lattice QCD data at unphysical pion masses (even close to the physical point) should be taken with caution. Our results at the physical point, similar to the lattice QCD data, show that a resonance/quasi-bound state may appear in the $I=0$ $\Lambda\Lambda$/$\Xi N$ channel.Comment: 20 pages, 8 figure

MODELO DE GESTÃO UNIVERSITÁRIA E SUA RELAÇÃO COM A RESPONSABILIDADE SOCIAL: UM ESTUDO DE CASO DO UNILASALLE CANOAS

O artigo tem por objetivo analisar o atual modelo de gestão do Unilasalle Canoas, com vistas aos seus compromissos fundacionais quanto à sua responsabilidade social. Faz parte de uma pesquisa maior que traz por título “Modelo de Gestão Universitária: um olhar para a governança a partir do Balance Scorecard (BSC) de uma IES comunitária do Sul do Brasil”. A metodologia adotada trata de estudo de caso envolvendo análise documental e revisão de literatura. Os conceitos trabalhados são modelo de gestão e responsabilidade social. Os achados da pesquisa reportam-se às ações sociais realizadas através do ensino, da pesquisa e da extensão universitária com destaque para os Projetos Comunitários, a Pastoral Universitária e o Tecnosocial Unilasalle. Ao final, conclui-se que o modelo de gestão adotado pelo Unilasalle está comprometido com a responsabilidade social efetivando-se em práticas em suas áreas administrativa e acadêmica