AbstractThis work presents a new methodology for the parametric optimization of piezoelectric actuators installed in laminated composite structures, with the objective of controlling structural vibrations. Problem formulation is the optimum location of a Macro Fiber Composite (MFC) actuator patch by means the maximization of the controllability index. The control strategy is based on a Linear Quadratic Regulator (LQR) approach. For the structural analysis, the modeling of the interaction between the MFC and the structure is made taking into account the active material as one of the orthotropic laminate shell layers. The actuation itself is modeled as an initial strain arising from the application of an electric potential which deforms the rest of the structure. Thereby, modeling the electric field and the electromechanical coupling within the actuator is avoided because these effects are considered analytically. Numerical simulations show that the structural model presents good agreement with numerical and experimental results. Furthermore, the results show that optimizing the location of the actuator in the structure helps the control algorithm to reduce induced structural vibration.

Este artigo analisa a disciplina partidária e as coalizões no plenário da Assembléia Legislativa de Santa Catarina, no período entre 1999 e 2006. Mostra que as taxas de disciplina, embora variem entre os principais partidos, são relativamente elevadas em seu conjunto, levando a uma significativa previsibilidade dos resultados das votações. Quanto às coalizões, a dimensão governo/oposição revelou ser mais significativa na formação de coalizões em plenário do que o posicionamento dos partidos na escala ideológica (esquerda/direita).

This article analyses party discipline and parliamentary coalitions at Santa Catarina's House of Representatives between 1999 and 2006. It shows that discipline ratios, though changing amidst the main parties, have been relatively high as a whole, causing some significant predictability in voting outcome. As for coalitions, the government/opposition dimension has shown to be more significant in parliamentary groupings than in the positioning of parties along the so-called left/right ideological scale.

Cet article analyse la discipline partidaire et les coalitions dans les sessions plénières de l'Assemblée Législative de Santa Catarina, dans la période comprise entre 1999 et 2006. Il démontre que les taux de discipline, quoique variant entre les principaux partis, sont, dans leur ensemble, relativement élevés, menant à une prévisibilité significative des résultats des votations. Quant aux coalitions, la dimension gouvernement/opposition s'est révélée être plus significative dans le formation de coalitions en session plénière, que la position des partis dans l'échelle idéologique (gauche/droite).

This paper proposes a cascade controller with friction compensation based on the LuGre model. This control is applied to a pneumatic positioning system. The cascade methodology consists of dividing the pneumatic positioning system model into two subsystems: a mechanical subsystem and a pneumatic subsystem. This division allows the introduction of friction compensation at force level in the pneumatic positioning system. Using Lyapunov's direct method, the convergence of the tracking errors is shown under the assumption that the system parameters are known. Experimental results illustrate the main characteristics of the proposed controller.

Este trabalho trata do controle dos sistemas pneumáticos de posicionamento e propõe uma estratégia em cascata que possibilita superação de diversos obstáculos inerentes ao seguimento preciso de trajetórias com estes sistemas. A convergência exponencial dos erros de seguimento em malha fechada no caso ideal é demonstrada utilizando o método de Lyapunov. Apresentam-se também as propriedades de robustez da malha fechada. Uma implementação experimental atesta a eficácia da estratégia.

This work deals with the control of pneumatic positioning systems and propose a cascade strategy that alow us to overcome several obstacles to the trajectory tracking in pneumatic systems. The exponential convergence of the closed loop trajectory tracking errors in the ideal case is demonstrated using Lyapunov's method. The robustness properties of the closed loop system are also presented. An experimental implementation attests the effectiveness of this strategy.