International audienceWe solve the open problem of global tracking control of 2nd-degree under-actuated lossless (without friction) Lagrangian systems via position measurements only. For flexible-joint robots, we design a dynamic controller which is based on measurements of link and joint positions only. Then, approximate differentiation is used for link velocities and a simple Luenberger observer for rotor velocities. The main results constitute a significant extension of recent work on observerless output-feedback control of Lagrangian systems. Strictly speaking, we establish uniform global asymptotic stability for the closed loop system

International audienceWe present a controller for flexible-joint robots without link velocity measurement. Our main result consists in a simple controller of the type proportional-derivative plus feedforward and a series of cascaded filters; the control design is reminiscent of classical backstepping control. To avoid the assumption that link velocities, accelerations and jerks are measured, we use approximate differentiation. The originality of our work lays in establishing uniform global asymptotic stability for the closed-loop system

International audienceWe contribute with a linear time-varying controller for the permanent magnet synchronous motor. We solve the open problem of speed-tracking control by measuring only stator currents and the rotor angular positions, under parametric uncertainty. Integral action is used to compensate for the effects of the unknown load-torque and adaptation is employed to estimate the unknown parameters. In the case that parameters are known (except for the load) we show that the origin of the closed-loop system is uniformly globally exponentially stable. For the case of unknown parameters we prove uniform global asymptotic stability hence, we establish parametric convergence. In contrast to other adaptive control schemes for electrical machines, we use a reduced-order adaptive controller. Indeed, adaptation is used only for the electrical dynamics equations. Moreover, not surprisingly, the closed-loop system has a structure well-studied in adaptive-control literature. Performance is illustrated in a numerical settin

<p>En este artículo se presenta el diseño y la aplicación de la teoría de control basada en pasividad para la integración de recursos energéticos distribuidos (REDs) a través de convertidores controlados por voltaje en redes monofásicas de corriente alterna. La representación Hamiltoniana de estos sistemas facilita el desarrollo de controladores pasivos que garantizan estabilidad en el sentido de Lyapunov para su operación en lazo cerrado. El modelado dinámico no autónomo de estos sistemas es transformado en un modelo incremental, el cual permite resolver el problema de seguimiento de trayectorias como un problema de regulación. La principal contribución de este trabajo radica en la capacidad de controlar el flujo de potencia activa y reactiva entre los REDs y la red eléctrica en función de la disponibilidad del recurso energético primario y la capacidad de los convertidores. Los resultados de simulación muestran que todos los controladores pasivos propuestos logran el objetivo de control, alcanzando el mismo desempeño dinámico que los controladores proporcionales integrales clásicos, garantizando estabilidad asintótica. Todas las simulaciones son desarrolladas bajo el entorno MATLAB/Simulink a través de la librería SimPowerSystems.</p>

The characterization of a class of electrical circuits is carried out in terms of both stability properties and steady-state behavior. The main contribution is the interpretation of the electrical topology (how the elements that conform the circuits are interconnected) in terms of mathematical properties derived from the structure of their models. In this sense, at what extent the topology by itself defines the dynamic behavior of the systems is explained. The study is based on the graph theory allowing capturing, departing from the well-known Kirchhoff laws, the topology of the circuits into several matrices with specific structure. The algebraic analysis of these matrices permits identifying conditions that determine whether the system is stable in the sense of Lyapunov and the kind of steady-state behavior that it exhibits. The approach is mainly focused on typical topologies widely used in practice, namely, radial, ring, and mesh networks.