SYMORO+: A SYSTEM FOR THE SYMBOLIC MODELLING OF ROBOTS

International audienceThis paper presents the software package SYMORO+ for the automatic symbolic modelling of robots. This package permits to generate the direct geometric model, the inverse geometric model, the direct kinematic model, the inverse kinematic model, the dynamic model, and the inertial parameters identification models. The structure of the robots can be serial, tree structure or containing closed loops. The package runs on Sun stations and PC computers, it has been developed under MATHEMATICA and C language. In this paper we give an overview of the algorithms used in the different models, the computational cost of the dynamic models of the PUMA robot are given

Compton Large Area Silicon Timing Tracker for Cosmic Vision M3

International audienceProposed in response to the ESA call for the third Medium size mission (M3), CAPSiTT is a small mission designed for a 3-year survey of the non-thermal high energy sky from an equatorial LEO orbit. With a large effective area and a very wide field of view, its single instrument, a silicon tracker, provides good imaging, spectroscopic and polarimetric capabilities with a sensitivity 10-100 times better than COMPTEL. Nucleosynthesis and particle acceleration mechanisms in various sites are the main scientific topics addressed by CAPSiTT

Antennas for the detection of radio emission pulses from cosmic-ray induced air showers at the Pierre Auger Observatory

The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna sensor. As the ultra-wideband reception of pulses is not widely discussed in antenna literature, we review the relevant antenna characteristics and enhance theoretical considerations towards the impulse response of antennas including polarization effects and multiple signal reflections. On the basis of the vector effective length we study the transient response characteristics of three candidate antennas in the time domain. Observing the variation of the continuous galactic background intensity we rank the antennas with respect to the noise level added to the galactic signal

Specification et implementation d'un mecanisme de communication de processus temps reel repartis

SIGLECNRS T 52955 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Design and analysis of a series-parallel hybrid 3-SPS-U mechanism

International audienceThis article presents the design and analysis of a seriesparallel hybrid mechanism. The mechanism has two stages which consist of a fixed base, an intermediate mobile platform and a mobile end-effector. Each stage is connected by three tension springs and a universal joint in the center. By correlating to a 3-SPS-U architecture, the geometrical equations for the mechanism are generated in the Euler space. To simplify the computations, the Tilt & Torsion space is employed for the analysis of the mechanism. A stability analysis is carried out initially to identify the optimum design parameters of the mechanism in the static mode. By employing algebraic methods, the singularity analysis of the mechanism is then carried out to generate the workspace and identify the tilt limits of the hybrid mechanism. A mapping equation which demonstrates the relation between the Tilt & Torsion angles and the Euler angles is then presented using the results of singularity analysis and numerical simulations. The mechanism under study is then proposed to be integrated on a piping inspection robot for passing through elbows and T-sections

Support Changes during Online Human Motion Imitation by a Humanoid Robot using Task Specification

6 pagesInternational audienceThis paper presents a method based on inverse kinematics with task specification for online human to humanoid motion imitation. We particularly focus on the problem of lifting and placing feet on the floor during the motion, allowing change of support during stepping or locomotion. The approach avoids the use of motion primitives that limit the robot motions to what had been learned. A direct transposition of movements is generated, allowing the robot to move freely in space as the human model does, at a velocity close to the reference one. The approach is validated on the humanoid robot NAO and shows very promising results for the use of online motion imitation

Identification and Control of a 3-X Cable-Driven Manipulator Inspired From the Bird’s Neck

International audienceAbstract This paper is devoted to the control and identification of a manipulator with three anti-parallelogram joints in series, referred to as X-joints. Each X-joint is a tensegrity one-degree-of-freedom mechanism antagonistically actuated with cables and springs in parallel. As compared to manipulators built with simple revolute joints in series, manipulators with tensegrity X-joint offer a number of advantages, such as an intrinsic stability, variable stiffness, and lower inertia. This design was inspired by the musculosleketon architecture of the bird’s neck, which is known to be very dextrous. A test-bed prototype is presented and used to test computed torque control laws. Friction and cable elasticity are modeled and identified. Their effect on the performance of control laws is analyzed. It is shown that in the context of antagonistic actuation and lightweight design, friction plays a leading role and the significance of modeling cable elasticity is discussed

The CIC library: a large insert YAC library for genome mapping in Arabidopsis thaliana

International audienc

The CIC YAC library : sizing of the clones and determination of clones carrying repeated DNA sequences

Journal electronique. URL : http://nasc.nott.ac.uk:300International audienc