401 research outputs found
A traveling-salesman problem for a class of carrier-vehicle systems
No full textThe traveling-salesman problem (TSP) for a class of carrier-vehicle systems in which a slow carrier with infinite operating range cooperates with a faster vehicle that has a limited operating range, was studied. A heuristic solution based on the Euclidean TSP (E-TSP) has been proposed and an analytical bound on its conservativeness has been derived. One of the main feature of this class of TSP problems is that, although still NP-hard, they admit polynomial-in-time optimization schemes. The CV-TSP heuristic proposed consists of two steps. First, it determines the visiting order of the almost-optimal E-TSP tour for the set of given points, and second, it uses the visiting order to solve the resulting visit of n points via the convex optimization formulation. The targets to be visited are limited to five randomly generated points that still make the computation of the exact optimal solution in a reasonable time possible.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Cooperative Pose Stabilization of an Aerial Vehicle through Physical Interaction with a Team of Ground Robots
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Piecewise quadratic Lyapunov functions over conical partitions for robust stability analysis
No full textIn this paper, the robust stability problem for uncertain linear continuous‐time systems is faced making use of piecewise quadratic Lyapunov functions (PQLF). PQLF are obtained by partitioning the state space into polyhedral cones and by associating a quadratic form with each cone. The proposed formulation allows us to recover, as particular cases of PQLFs, not only the class of quadratic functions but also the class of polyhedral functions. In this way, we manage to show the universality of the class of PQLF for the robust stability problem. The main contribution of the paper is the formulation of a low‐computational cost procedure for the stability analysis of uncertain linear systems. Several numerical examples are included in the paper, where the proposed approach is tested on some benchmark cases taken from the literature. Comparisons with existing methods show that the proposed method performs better under several aspects
Constrained Control of Linear Discrete-Time Systems under Quartic Performance Criterion
No full textIn several applications, a performance criterion that is quartic in the state can be a desired alternative to the classic quadratic control. This letter proposes a receding horizon controller for linear time-invariant systems subject to linear state and input constraints, which makes use of a running cost that is quadratic in the input and quartic in the state. Stability and recursive feasibility of the proposed receding horizon scheme are proven. Numerical simulations are presented, considering the problem of controlling a single-link inverted pendulum on a cart.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Switching Control Laws in the Presence of Measurement Noise
No full textIn this paper we study a class of systems governed by piecewise continuous control laws, subject to measurement noise and such that more than one state configuration could be a desired point for the system to be stabilized. Such a problem is common in many practical situations, including, for example, vehicle attitude control, robotic manipulator positioning, deployment of multistable structures, etc. Our aim is to characterize, both for continuous and discrete-time models, control properties and switching policies ensuring that any possible state trajectory of the closed-loop system is robustly asymptotically convergent to one of the desired ``target points''. First we will show that in the discrete-time case, conditions guaranteeing the asymptotic stability to a set of points can be derived by exploiting the intrinsic ``holding'' nature of the discrete-time framework. Such results can be extended to continuous time by means of standard sample-and-hold techniques. However, this kind of solution is revealed to be very conservative and then not realistically employable in many contexts. For such a reason further less restrictive policies will be introduced and investigated; these are mostly based on the concept of ``strategy holding'' in time (by providing a slower switching policy sampling time) and space (by using hysteresis regions). Those strategies will be characterized both in terms of global stabilizability and in terms of switching flexibility, i.e. the capability to react in a convenient way to sudden state changes. Driven by the above analysis an ``opportunistic switching'' strategy combining all the advantages of the strategies considered will be proposed and analyzed. Synthesis results are presented, providing a constructive procedure to design the proposed control laws. The paper is concluded with an application example based on the attitude control of a Ducted-Fan Aerial Vehicle, showing the effectiveness of the proposed approach in a practical application.info:eu-repo/semantics/publishe
Lectura crítica sobre Roldán Vera, E. (2022). Libros, negocios y educación. la empresa editorial de Rudolph Ackermann para Hispanoamérica en la primera mitad del siglo XIX. Ciudad de México: Universidad Autónoma Metropolitana
No full textRevisión de Libros, negocios y educación: la empresa editorial de Rudolph Ackermann para Hispanoamérica en la primera mitad del siglo XIX de E. Roldán VeraFil: Garone Gravier, Marina. Instituto de Investigaciones Bibliográficas, Universidad Nacional Autónoma de México, México
Wireless Sensor Networks Clock Synchronization with Selective Convergence Rate
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Clock Synchronization for Wireless Sensor Networks with Communication Delay
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Robust Stability of Linear Uncertain Systems through Piecewise Quadratic Lyapunov Functions defined over Conical Partitions
No full textIn this paper a class of Piecewise Quadratic Lyapunov Functions (PQLFs) for the analysis of the robust stability of linear systems subject to polytopic uncertainties is considered. These functions are obtained by partitioning the state space into polyhedric conical sets and by associating to each cone a quadratic form. This class of Lyapunov functions is not only a generalization of quadratic Lyapunov functions but it also (strictly) contains the class of polyhedral Lyapunov functions. The latter implication directly proves the universality of these functions for the robust stability problem and justifies the effort of finding a Lyapunov function belonging to this class. The technicalities for an effective use of this class of functions to test the robust stability of linear uncertain systems will be detailed. Numerical examples show that the proposed methodology allows one to obtain results that, compared with the actual state of the art, perform better under several viewpoints. © 2012 IEEE.info:eu-repo/semantics/publishe
Entrevista a la Dra. Marina Garone Gravier - Cultura gráfica: interfaz de conocimiento
No full textEntrevista com a Dra. Marina Garone Gravier, referência no campo de estudos da história dos livros e tipografia na América Latina. Sua visão vai desde o início da impressão na América até o presente, proporcionando assim uma plataforma fundamental para um campo de estudos ainda novo na região.Entrevista a la Dra. Marina Garone Gravier, figura referente en el campo de los estudios de la historia del libro y la tipografía en América Latina. Su mirada se desplaza de México a Argentina y comprende desde los comienzos de la imprenta en América hasta la actualidad aportando así una plataforma fundamental para un campo de estudios aún novedoso en la región
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