Design of a flight test instrument system for measuring and analyzing of vibration signals on a helicopter

Health and monitoring of aircraft vibrations are crucial to safety. To maintain safe flying, helicopter vibration levels should be kept at a minimum. Therefore, vibration signal analysis and systems that measure vibration levels are very important topics in the avionics industry. In the scope of this thesis, Flight Test Instrument (FTI) system is designed for data acquisition purposes. Designed FTI system consists of power module, controller module, analog input module and backplane module. The power module converts input power to desired levels according to system requirements. The controller module is responsible for calculations and communication due to having an FPGA on board. The analog input module is responsible for interfacing with the sensors, signal conditioning, and sampling the vibration signals. The backplane is designed for combining all the modules together. The study also contains vibration signal analysis. In order to determine the vibration level and phase different approaches were made. First of all, for determining vibration magnitude, FFT implementation has been made, and for the phase calculation several digital filters were designed and implemented into the system. Algorithms that are developed have been verified in laboratory environments with a constant vibration generator device then measurements from a helicopter had been taken in order to measure the vibration level. To compare the results a commercial of the shelf (COTS) device was used in helicopter experiments and the results and comparisons have been shared. Afterward, several machine learning algorithms (such as SVM, GPR, linear regression etc.) are trained for vibration both magnitude and phase prediction. Simulation results have been shared and evaluated for these algorithms. KEYWORDS: Signal Processing, Machine Learning, Hardware Design, Flight Test Instrument, Algorithm Development, Vibration Signals