| Abstract [eng] |
Magnetic bistable sensors due to their unique properties are getting more and more attention. Magnetic hysteresis width of bistable sensors is sensitive to temperature and mechanical stresses. In addition, hysteresis width is evaluated wirelessly by analyzing sensor’s reaction to the alternating magnetic field. Contactless measurement possibility allows to integrate bistable sensors inside the materials and makes them suitable for many monitoring applications like medicine and aviation. Although magnetic bistable sensors are an active research field, there is little information about their practical application and response to external factors. The aim of this work is to investigate the possibilities of wireless temperature and mechanical stress measurements using magnetic bistable sensors. In the analytic part of this work manufacturing technologies, magnetic properties and factors affecting hysteresis width of bistable sensors are described. Equipment for temperature and mechanical stress experiments is described in the methodical part of this work. Moreover, signal modeling algorithms for testing signal filtering and parametrization methods are explained there. Simulation results of magnetic field distribution generated by different types of excitation coils are presented and discussed in the results section. In addition, filtering quality results obtained from testing the proposed filtering method with simulated and real response signals are included. An error of automated hysteresis width measurement algorithm was also evaluated. Furthermore, impact of external factors (temperature, permanent and alternating magnetic field) to the hysteresis width of the sensors are described and analyzed. Conclusions and future directions are presented at the end of this work. |
