27,339 research outputs found
Cryomorphological topographies in the study of ice caves
Producción CientíficaThe current interest in ice caves requires that their varied manifestations be known as accurately as possible in view of their responses to a global change and also to their great potential as paleoenvironmental witnesses. This phenomenon has been known about for a long time but is still scarcely studied from the point of view of its cryological values and the evolution and distribution of many of their morphologies. For this, the development of cryomorphological topographies from traditional techniques to geodetic surveys with different tools, including terrestrial laser scanning, is one of the most current ways to characterize and quantify this type of cryospheric phenomena. It represents a new kind of periglacial cartography whose use is feasible in spite of the difficulties these environments present.Ministerio de Economía, Industria y Competitividad (project CGL2015-68144-R
MIMO PID Controller Tuning Method for Quadrotor Based on LQR/LQG Theory
In this work, a new pre-tuning multivariable PID (Proportional Integral Derivative)
controllers method for quadrotors is put forward. A procedure based on LQR/LQG (Linear Quadratic
Regulator/Gaussian) theory is proposed for attitude and altitude control, which suposes a considerable
simplification of the design problem due to only one pretuning parameter being used. With the aim to
analyze the performance and robustness of the proposed method, a non-linear mathematical model of
the DJI-F450 quadrotor is employed, where rotors dynamics, together with sensors drift/bias properties
and noise characteristics of low-cost commercial sensors typically used in this type of applications are
considered. In order to estimate the state vector and compensate bias/drift effects in the measures,
a combination of filtering and data fusion algorithms (Kalman filter and Madgwick algorithm for attitude
estimation) are proposed and implemented. Performance and robustness analysis of the control system
is carried out by employing numerical simulations, which take into account the presence of uncertainty
in the plant model and external disturbances. The obtained results show the proposed controller design
method for multivariable PID controller is robust with respect to: (a) parametric uncertainty in the plant
model, (b) disturbances acting at the plant input, (c) sensors measurement and estimation errors
Optical sensor to measure the projectile velocity
Displays & Photonics Applications Group (GDAF), belonging to Electronics Technology Department of University Carlos III of Madrid (Spain), has designed and implemented a simple, cost-effective, and robust optoelectronic system to measure online the average velocity of a projectile. This system is able to measure velocities ranged between 100m/s and 1200m/s). Potential applications are focused on experimental impact tests on aircraft and spacecraft structures. We are seeking potential collaborations with international/national research centres and enterprises to extent the range of potential applications
Dimuon results in PbPb and pp collisions in CMS
The LHC offers unique opportunities for studying the properties of hot QCD
matter created in Pb+Pb collisions at extreme temperatures and very low parton
momentum fractions. With its high precision, large acceptance for tracking and
calorimetry, and a trigger scheme that allows analysis of each minimum bias
Pb+Pb event, CMS is fully equipped to measure dimuons in the high multiplicity
environment of Pb+Pb collisions. Such probes are especially relevant since they
are produced at early times and propagate through the medium, mapping its
evolution. The capabilities of the CMS experiment to study dimuon production in
pp and Pb+Pb collisions based on the 2010 LHC runs will be reviewed. CMS is
able to measure primary and secondary J/psi, as well as the three Upsilon
states. Quarkonia results at sqrt(s)=2.76 TeV in pp and Pb+Pb will be
presented, including a tantalizing observation of suppression of the Upsilon
excited states. The Z0 boson inclusive and differential measurement as a probe
of the initial state will be described.Comment: 3 pages, 4 figures. To appear in the proceedings of PANIC 201
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