A method for Kinematic Calibration of a Parallel Robot by using one camera in hand and a spherical object

The main purpose of robot calibration is the correction of the possible errors in the robot parameters. This paper presents a method for a kinematic calibration of a parallel robot that is equipped with one camera in hand. In order to preserve the mechanical configuration of the robot, the camera is utilized to acquire incremental positions of the end effector from a spherical object that is fixed in the word reference frame. The positions of the end effector are related to incremental positions of resolvers of the motors of the robot, and a kinematic model of the robot is used to find a new group of parameters which minimizes errors in the kinematic equations. Additionally, properties of the spherical object and intrinsic camera parameters are utilized to model the projection of the object in the image and improving spatial measurements. Finally, the robotic system is designed to carry out tracking tasks and the calibration of the robot is validated by means of integrating the errors of the visual controller.

The 15th International Geological Congress, South Africa (1929): The Resurgence of Wegener’s Continental Drift Theory

The 15th International Geological Congress was held in South Africa in 1929. Many interesting issues were tackled, thanks to the development of geophysical techniques, ideas about magmatic differentiation, and the origin of the Karroo System, among others. The importance of the Congress from the point of view of the history of geology lies in the fact that an ‘inflection point’ occurred as regards thinking about the continental drift theory that had been proposed by Wegener a few years earlier. It can be said that the contributions of Du Toit allowed a deepening in the theoretical bases of this scientific hypothesis, which celebrated its first hundred years in 2012.

Spanish ribbed vaults in the 15th and 16th centuries

Proceedings of the First International Congress on Construction History : Madrid, 20th-24th January 2003

Discurso pronunciado por el Excmo. Sr. D. Rafael Portaencasa Baeza, Rector Magnífico de la Universidad Politécnica de Madrid, en el solemne acto académico con motivo de la Festividad de Santo Tomás de Aquino e Investidura de Doctores Honoris Causa de los Profesores Dres. Paul Lacombe, Michel Carpentier y John McCarthy

Discurso pronunciado por D. Rafael Portaencasa con motivo de la Festividad de Santo Tomás de Aquino e investidura de Doctores "Honoris Causa" de los profesores Lacombe (científico de renombre en el campo de Minas), MacCarthy (destacado investigador en el campo de la inteligencia artificial) y Carpentier.