1,721,238 research outputs found
A cooperative control strategy for yaw rate and sideslip angle control combining torque vectoring with rear wheel steering
Full text linkAutomobiles are becoming more and more complex as multiple control systems are integrated into the vehicle platform. This paper investigates the coordination of active rear steering (RWS) and torque vectoring (TV)–which is enabled by independent electric motors at the rear axle–in controlling vehicle lateral dynamics. The proposed controller aims at enhancing vehicle handling performance and stability while cornering. The coordination of the two actuators is achieved by weighting their contribution based on their impact on vehicle dynamics according to the working condition. The impact of each control system is assessed by means of phase portraits. These plots are a very powerful tool for analysing vehicle nonlinear dynamics as they readily display vehicle stability properties and map equilibrium point locations and movement to changing parameters and control inputs. Based on phase portrait analysis, a performance index is thus proposed, which weights more the control action (TV or RWS) capable of leading the vehicle at the nearest equilibrium point with the fastest rate. The controller performance is assessed through numerical simulations carried out using a nonlinear 14 dofs vehicle model. Results are compared with ones of the two controllers alone (RWS and TV) in different manoeuvers and adherence conditions
Force-based braking control algorithm for vehicles with electric motors
No full textElectric motors offer the possibility to control the braking torque in a more precise way than the hydraulic circuit. The applied torque is in fact measured and so it can be used to feedback the controller. Moreover, this information can be used to estimate the tyre-road friction coefficient, before potential friction is reached. The present paper proposes a novel ABS control strategy for electric vehicles with distributed motors. The controller is a six states machine that uses the information on applied braking torque provided by the electric motors. This information is of paramount importance to understand when the wheel reaches the peak of the braking force. Simulation results shows the benefits of the proposed strategy, comparing the results with state of the art acceleration-based controller
Present and future strategies for Neutrinoless Double Beta decay searches
No full textThe study of neutrino properties is one of the fundamental challenges in particle physics. In the last years, several progresses have been made, but still we do not know the absolute mass of neutrinos or whether they are Dirac or Majorana particles. The only way to probe the neutrino nature is through the observation of Neutrinoless Double Beta Decay, a not yet observed nuclear transition which emits two electrons and no neutrinos. In this paper, after a brief introduction to the topic, the present and future strategies to detect this process are presented
Torque vectoring control for different powertrain layouts of hybrid and electric vehicles
No full textIn recent years the need in energy saving in transportation raised the attention on alternative powertrain. The main competitor of ICE become electric motors. With this type of powertrain it is possible to drastically change the power train layout of a vehicle. It is in fact possible to equip the vehicle with more than one single motor. In this paper the author analyses the effectiveness of a control strategy for lateral dynamics applied on different powertrain layouts comparing the performance of each layout with respect to others and with respect to the passive equivalent vehicle
Signal and noise simulation of CUORE bolometric detectors
No full textBolometric detectors are used in particle physics experiments to search for rare processes, such as neutrinoless double beta decay and dark matter interactions. By operating at cryogenic temperatures, they are able to detect particle energies from a few keV up to several MeV, measuring the temperature rise produced by the energy released. This work focusses on the bolometers of the CUORE experiment, which are made of TeO2 crystals. The response of these detectors is nonlinear with energy and changes with the operating temperature. The noise depends on the working conditions and significantly affects the energy resolution and the detection performances at low energies. We present a software tool to simulate signal and noise of CUORE-like bolometers, including effects generated by operating temperature drifts, nonlinearities and pileups. The simulations agree well with data. © 2011 IOP Publishing Ltd
Modelling of the Vertical Dynamics of an Electric Kick Scooter
Full text linkNowadays, micro-mobility is one of the major global trends in cities for the innovation of the transport system. In this context a breakthrough introduction of electric kick scooters (e-scooters) has taken place. Unfortunately, these mobility systems cause several accidents mainly for two reasons: wrong use and inadequate safety requirements. Since e-scooters are quite a new type of vehicle, generally accepted mathematical models are yet to be developed. These models can be useful in understanding the dynamical properties of this type of vehicle thus improving its design to reduce riding accidents. The present paper presents a model for the simulation of the vertical dynamic behavior of e-scooters that accounts also for the mechanical impedance of the driver, thus allowing to estimate the overall driver's comfort and road holding capabilities providing information on possible speed limitations in case of bad road conditions. Furthermore, the paper shows experimental envelope curves for lumped obstacles obtained with a dedicated test bench on which the e-scooter is fixed and tested under different conditions of vertical load and tire inflation pressure
Optimizing the energy threshold of light detectors coupled to luminescent bolometers
No full textBolometers have proven to be good detectors for the search of neutrinoless double beta decay. By operating at cryogenic temperatures, they feature excellent energy resolution and low background. The detection of the possible light emitted when particles interact in the bolometer is a promising method to lower the background of the experiments. The different amount of light emitted in β/γ and α interactions, whether due to scintillation or Cerenkov emission, allows to discriminate the two interaction types. Because of the cryogenic environment, light detectors are often bolometers. In this work we present a software algorithm to lower the energy threshold of bolometric light detectors coupled to luminescent bolometers. The application to data from Ge light detectors coupled to ZnMoO 4 and TeO 2 bolometers shows that the energy threshold can be lowered substantially, increasing the discrimination power when the amount of emitted light is small. © 2011 IOP Publishing Ltd and SISSA
Estimation of waveform deformation with the matched filter
Full text linkIn many particle physics experiments the data processing is based on the analysis of the digitized waveforms provided by the detector. While the waveform amplitude is usually correlated to the event energy, the shape may carry useful information for event discrimination. Thanks to the high signal to noise ratio they provide, matched filters are often applied. Their original design is however intended for the estimation of the waveform amplitude only. In this work we introduce an analytical extension of the original matched filter for the estimation of a possible shape deformation with respect to a reference template. The new filter is validated on simulations and, with respect to shape parameters calculated on unfiltered waveforms or derived from the original matched filter, it improves the discrimination capability by at least a factor 2 both at low and high signal to noise ratios, making it applicable to the data of several experiments
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