Blade Tip Timing (BTT) is a non-intrusive method to measure blade vibration in turbomachinery. Time of Arrival (TOA) is recorded when a blade is passing a stationary sensor. The measurement data, in form of undersampled (aliased) tip-deflection signal, are difficult to analyze with standard signal processing methods like digital filters or Fourier Transform. Several indirect methods are applied to process TOA sequences, such as reconstruction of aliased spectrum and Least-Squares Fitting to harmonic oscillator model. We used standard sine fitting algorithms provided by IEEE-STD-1057 to estimate blade vibration parameters. Blade-tip displacement was simulated in time domain using SDOF model, sampled by stationary sensors and then processed by the sinefit.m toolkit. We evaluated several configurations of different sensor placement, noise level and number of data. Results of the linear sine fitting, performed with the frequency known a priori, were compared with the non-linear ones. Some of non-linear iterations were not convergent. The algorithms and testing results are aimed to be used in analysis of asynchronous blade vibration.
Paulina Kurnyta-Mazurek, Artur Kurnyta, Agnieszka Pręgowska, Krzysztof Kaźmierczak and Leszek Frąś
The paper presents the results of work on control and monitoring systems of an active magnetic bearings for the aircraft engine. Mathematic model of the active homopolar electromechanical actuator with permanent magnets is expanded. Mathematical model of the test object is developed what allows to propose a control algorithm. The experimental verification of this theory was performed on the laboratory test stand. Moreover, special monitoring system is also designed. Presented comprehensive approach allows increasing reliability of the aircraft engines, as well as in wind turbines, electric drives and machine tools spindles.
Bartosz Brzozowski, Karol Kawka, Krzysztof Kaźmierczak, Zdzisław Rochala and Konrad Wojtowicz
Maintenance of aircraft is a complex process and therefore, in order to optimize the process, integrated information systems are increasingly used. Rapid development and wide availability of mobile devices equipped with powerful processors and with a wide range of modern communication connections suggests their high usability for enterprise IT systems. In the Department of Avionics and Air Armament of the Military University of Technology (WAT) an ERP-class (Enterprise Resource Planning) system, intended to support aircraft maintenance  has been designed and developed. The main concept of the system is to store the aircraft related and maintenance information in a central repository, i.e. in databases hosted on a central database server. This solution ensures concurrent availability of the data to a large group of authorized users. The key components of the system include the database server and client applications, which ensure access to centralized information resources, according to assigned user rights. The project involves development of client applications using three technologies: web, desktop and mobile one. Developed client applications have successfully passed integration tests perfomed using sample maintenance data. Currently works on user authorization security and wireless data security are under way.