Kybernetika pro materiálové vědy
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- ItemStatistical Evaluation of Pilot’s Behavior Models Parameters Connected to Military Flight Training(MDPI, 2020-08-28) Jirgl, MiroslavThe paper discusses the possibilities of objective assessment of military flight training quality based on statistical evaluation of pilot’s behavior models parameters. For these purposes, the pilots’ responses to non-standard flight situations were measured by using a fixed-base and a moving-base engineering flight simulator. Tens of military pilots at different training stages were tested. By exploiting real-life tests, we established that the given pilot models provide sufficiently accurate approximation of realistic human responses. Importantly, the models are relatively easy to use, and the individual parameters can be unambiguously interpreted, i.e., the time constants of the pilot behavior model are obtainable, representing the pilot’s current psychological and physiological state of mind. The parameters lay in the defined ranges, and they characterize the ability of the human/pilot to adapt to a controlled dynamic system. Consequently, a fundamental statistical analysis based on pilot’s behavioral model parameters was conducted, using the acquired test data representing the pilot’s behavior during repeated measuring. The initial results indicate the possibility to use the results for objective assessment the military flight training level.
- ItemHigh Speed Operation Tests of Resolver Using AURIX Microcontroller Interface(IFAC, 2018-05-23) Kozovský, Matúš; Blaha, PetrThis paper demonstrates possibility to use microcontroller AURIX TC277 interfaces for resolver signal processing and also for its carrier signal generation. Resolver support is integrated in Delta-Sigma analog to digital converter module. This module also contains resolver carrier signal generation. The paper also describes needed configuration and achieved results for the electrical speeds up to 80 krpm. Measured resolver position is compared with encoder position which is taken as a reference. The results from real experiments on a prepared hardware setup are also contained. The steps needed to achieve good compensation and correspondence between both sensors are detailed.
- ItemConditional oscillation of half-linear Euler-type dynamic equations on time scales(University of Szeged, 2015-02-18) Hasil, Petr; Vítovec, JiříWe investigate second-order half-linear Euler-type dynamic equations on time scales with positive periodic coefficients. We show that these equations are conditionally oscillatory, i.e., there exists a sharp borderline (a constant given by the coefficients of the given equation) between oscillation and non-oscillation of these equations. In addition, we explicitly find this so-called critical constant. In the cases that the time scale is reals or integers, our result corresponds to the classical results as well as in the case that the coefficients are replaced by constants and we take into account the linear equations. An example and corollaries are provided as well.
- ItemPrognosis and Health Management in electric drives applications implemented in existing systems with limited data rate(IEEE, 2019-09-10) Klíma, Bohumil; Buchta, Luděk; Doseděl, Martin; Havránek, Zdeněk; Blaha, PetrImportance of the condition monitoring and predictive maintenance in motion systems is growing up as motion systems quantum and their complexity (number of axes, performance parameters) increases with increasing the automation of huge range of human activities and manufacturing processes. Probability of failures increases with the system complexity. Many faults and indication of their propagation in the electric drives would require additional sensors or hardware, higher bandwidth and sampling frequencies of feedback sensors, high computing power etc. for development of sophisticated methods to detect specific faults with good sensitivity, robustness and reliability under any operating condition. This paper presents an approach to the condition monitoring and prognosis applicable into the existing systems. These methods use the information available in the traditional electric drives – especially the information from the individual sensors in a voltage source inverter (VSI) and/or an electric motor. Condition indicators for these methods are based on application specific operating states or actions, which generates typical patterns in the signals. The condition monitoring is based on observing the deviations of these patterns between the healthy system and the system with fault propagating. The implementation strategy is described in the paper and some demonstration examples are shown as well.
- ItemAn Automated measurement system for measuring an overall power efficiency and a characterisation of piezo harvesters(IOP Publishing, 2018-09-05) Kunz, Jan; Fialka, Jiří; Beneš, Petr; Havránek, ZdeněkSystems for measurement power characteristics of piezo harvesters in dependence on a frequency and a load resistance are not commonly used due its complexity. Therefore, the parameters are usually measured manually near its resonant frequency. In some cases, it is convenient to measure the characteristics in a broader range of parameters. Then, in order to achieve more precise results and effective measurement we decided to develop our own measurement system. The system controls an effective value of vibrations, sets a frequency and a load resistance for measuring a power generated by a piezo harvester and measures a tip displacement of the harvester. These quantities are used for a characterisation of piezo harvesters. Moreover, the voltage and current on vibration exciter are measured to evaluate the overall efficiency of the harvester. The system was tested on a harvester MIDE PPA-1001 for various added weights and vibration levels from 0.1 to 0.5 g. The measured data analysed and the efficiency was calculated as a ratio between a vibration power consumed by the harvester and its electrical output. The evaluated overall efficiency varies between 10 and 15 % nearby its optimal working conditions.