233 publications from this institution
This paper proposes an image-based visual-servoing algorithm that allows for optimal formation control. The proposed distributed controller utilizes visual features of other team members, retrieved from images captured by onboard cameras, to autonomously plan and perform formation acquisition, keeping or reconfiguration maneuvers. The problems of minimization of the control effort is analyzed and the paper proposes an optimal framework for developing controllers that address the issue. The viability of such a technique is explored through numerical simulations.
La presente investigacion docente engloba la generacion de recursos web y multimedia. Para ello, se ha puesto a disposicion de los alumnos en una web mediante el gestor de contenidos Joomla. Ademas, se han creado materiales, que estan disponibles en la web para los alumnos, que incluyen presentaciones y grabaciones en video de las clases. De esta manera, los alumnos pueden volver a ver una clase con el objetivo de reforzar los conocimientos adquiridos o seguir la docencia si, por algun motivo, no pudieron asistir. La plataforma propuesta se ha probado con las asignaturas Sistemas de Control Automatico y Robotica del Master Universitario en Automatica y Robotica.
Calibration techniques allow the estimation of the intrinsic parameters of a camera. This paper describes an adaptive visual servoing scheme which employs the visual data measured during the task to determine the camera intrinsic parameters. This approach is based on the virtual visual servoing approach. However, in order to increase the robustness of the calibration several aspects have been introduced in this approach with respect to the previous developed virtual visual servoing systems. Furthermore, the system is able to determine the value of the intrinsic parameters when they vary during the task. This approach has been tested using an eye-in-hand robotic system.
The utilization of zooming cameras during a non-cooperative rendezvous in space is investigated in this paper. An image-based controller, utilizing visual servoing techniques usually applied to ground-based robotic systems, is designed for the particular problem of far-to-close approach of a spacecraft to a non-cooperative object. The controller directly utilizes the visual features from image frames of the noncooperative target for computing both attitude and orbital maneuvers concurrently. The additional feature derived from the utilization of the zooming camera gives a greater versatility to the maneuvers if compared with the classic fixed optics approaches. The stability of the proposed controller is proven analytically in the invariant space, and its viability is explored through the application to a realistic space debris removal scenario.
Las aplicaciones de este tipo de sistemas son muy amplias, asi, encontramos trabajos en la actualidad en los que se describe algunas de ellas como en [5] que usa la alta resolucion de un dispositivo optico, por ejemplo, un microscopio, para realizar el microposicionamiento de las partes implicadas realizando una servo-visualizacion. Corke, Roberts y Winstanley [2], describen una aplicacion para la industria minera. De nuevo, en [10] encontramos una aplicacion de visual servoing aplicada a la robotica, en este caso se trata de aplicar a tareas de navegacion de un robot el conocimiento proporcionado de la realimentacion visual.
Abstract In this article, a nonlinear optimal control approach is proposed for the dynamic model of 3-DOF four-cable driven parallel robots (CDPR). To solve the associated nonlinear optimal control problem, the dynamic model of the 3-DOF cable-driven parallel robot undergoes approximate linearization around a temporary operating point that is recomputed at each time-step of the control method. The linearization relies on Taylor series expansion and on the associated Jacobian matrices. For the linearized state-space model of the 3-DOF cable-driven parallel robot a stabilizing optimal (H-infinity) feedback controller is designed. To compute the controller’s feedback gains an algebraic Riccati equation is repetitively solved at each iteration of the control algorithm. The stability properties of the control method are proven through Lyapunov analysis. The proposed nonlinear optimal control approach achieves fast and accurate tracking of reference setpoints under moderate variations of the control inputs and a minimum dispersion of energy.
This work was funded by the Spanish MCYT project DPI2005-06222 “Diseno, implementacion y experimentacion de escenarios de manipulacion inteligentes para aplicaciones de ensamblado y desensamblado automatico” and by the project GV05/007: “Diseno y experimentacion de estrategias de control visual-fuerza para sistemas flexibles de manipulacion”.
