Ústav automatizace a měřicí techniky


Recent Submissions

Now showing 1 - 5 of 86
  • Item
    Robust perception systems for automated, connected, and electrified vehicles: advances from EU project ArchitectECA2030
    (Elsevier, 2023-12-13) Recekenzaun, Jakob; Solmaz, Selim; Goelles, Thomas; Hilbert, Marc; Weimer, Daniel; Mayer, Peter; Chromý, Adam; Hentschel, Uwe; Modler, Niels; Toth, Mate; Hennecke, Marcus
    The perception supply chain (SC1) of the ArchitectECA2030 project investigates failure modes, fault detection, and residual risk in perception systems of electrified, connected, and automated (ECA) vehicles. This accounts for the needs of a reliable understanding of the surrounding environment. The three demonstrators of SC1, described in this paper, address steps of a typical ECA usage cycle: charge - drive - restart charging. The foreign object detection (FOD) demonstrator improves safety within a wireless charging system. The robust physical sensors demonstrator creates a more robust perception by detecting failures within fused and single sensor data. The position enhancement demonstrator improves vehicle localization in areas with reduced GNSS signal coverage. All demonstrators are linked to the challenges that occur during the ECA vehicle usage cycle
  • Item
    Recursive Variational Inference for Total Least-Squares
    (IEEE, 2023-06-26) Friml, Dominik; Václavek, Pavel
    This letter analyzes methods for deriving credible intervals to facilitate errors-in-variables identification by expanding on Bayesian total least squares. The credible intervals are approximated employing Laplace and variational approximations of the intractable posterior density function. Three recursive identification algorithms providing an approximation of the credible intervals for inference with the Bingham and the Gaussian priors are proposed. The introduced algorithms are evaluated on numerical experiments, and a practical example of application on battery cell total capacity estimation compared to the state-of-the-art algorithms is presented.
  • Item
    Measurement of thermal depolarization effects in piezoelectric coefficients of soft PZT ceramics via the frequency and direct methods
    (Elsevier Ltd., 2016-09-01) Fialka, Jiří; Beneš, Petr; Michlovská, Lenka; Klusáček, Stanislav; Pikula, Stanislav; Dohnal, Přemysl; Havránek, Zdeněk
    Depolarization at high temperatures around the Curie point constitutes an important yet difficultly measurable material property of piezoelectric (PZT) ceramics. The common vibrometric technique (d33 meters) is not suitable for the measurement of temperature dependences, and therefore we used the frequency method to perform the desired procedures. The indicator selected to show the depolarization state in the piezoelectric ceramics consisted in the piezoelectric charge coefficient, whose value can be effectively measured via the above-mentioned frequency technique. The accuracy of the method was verified via comparing a d33 meter constructed by the authors (as described in this paper) and also by means of differently sized cylinders of ceramics NCE51, which are designed for longitudinal length modes. Based on the obtained results, we established a measurement methodology to exactly determine the value of the Curie point that corresponded to the phase transition to a cubic crystallographic structure. The experiment also confirmed the applicability of progressively controlled depolarization of PZT ceramics by high temperature in the range of between 350 and 370 °C, and it defined the temperature limits at which there occur irreversible changes of the piezoelectric properties of PZT ceramics. In the measured NCE51 material, the limit for irreversible changes was equal to 95% of the Curie temperature (368 °C).
  • Item
    Comparison of Methods for the Measurement of Piezoelectric Coefficients
    (IEEE, 2013-04-03) Fialka, Jiří; Beneš, Petr
    The charge constant of piezoelectric material is one of the crucial constant values. At the present time, the measurement of this value is mostly realized by means of three techniques: the frequency method, the laser interferometer technique, and the quasi-static method. These techniques have been practically applied to piezoelectric ceramic samples. Our paper presents comparison of the individual methods with regard to their accuracy and the demands placed on the instrumentation and preparation of the piezoelectric material samples. A soft ceramic product marketed under the production code of NCE51 was used in the experiments. The methods are described in detail, including the process of sample preparation, description of the experiments, and procedure of alculating coefficients from the measured values.
  • Item
    Confirmation of mathematical model of Helmholtz coils on the real construction
    (DAAAM International Vienna, 2011-11-23) Uher, Miroslav; Vágner, Martin; Fialka, Jiří
    This paper deals with distribution of magnetic field inside paired coils in Helmholtz arrangement. Helmholtz coils consist of two separate coils. Their mutually arrangements is advantageous for generation of uniform magnetic field. The simulation of field uniformity was realized. Further, the Helmholtz coils was made and the amplitude of magnetic field vector was measured. The comparison between simulation and really obtained results is discussed in this paper.