• Mahadevi K C

An aircraft when airborne has to maneuver depending on weather conditions and various other reasons. In a straight or level flight there is only vertical component acting on the aircraft. In extreme conditions, such as mountains terrains, the plane may have to take 180-degree turn. During this maneuver, the vertical component increase that is the aircraft experiences a higher value of acceleration due to gravity, say 2g, 3g or even up to 8g to 10g. During the lifetime of an aircraft, it experiences many such increased values of ‘g’ and each time a stress is developed on the aircraft wings which is built over a period of time and converts into fatigue. The fatigue starts as a crack on the wings which keeps spreading throughout, thus leading to the breakdown of the aircraft. It is to measure this fatigue that a fatigue meter is used. The fatigue in case of aircraft is sensed by the accelerometer in terms of vertical acceleration. When the aircraft is continuously flying and maneuvering, then depending on the design of the aircraft and the structure of aircraft, certain parameters like vertical ‘g’ are more prone for inducing fatigue. The vertical ‘g’ of interest is loaded in a look up table. The sensed ‘g’ is compared with the stored ‘g’ and the number of times the aircraft encountering the difference in ‘g’ is recorded. This recorded ‘g’ is milked out and can be analyzed off-line to calculate the remaining life of aircraft. The paper aims at developing a portion of fatigue meter, which uses accelerometer to sense the G-force and determine number of G level crossings during a single flight. We are using a 16-bit PIC microcontroller which has a 10-bit internal ADC. G crossing detection algorithm is programmed into microcontroller, based on this algorithm g values are calculated. The microcontroller based system is interfaced with an LCD, and UART which are used to display g crossing, g value with corresponding time stamps. Real time clock is used for time stamping f the G level crossings. Eight switches are provided to display corresponding g counters on the LCD display. This recorded g crossing data are used for further processing, to estimate remaining life of aircraft.

Airborne, maneuver, fatigue, look up table, g level crossings, g- force, g crossing detection algorithm

"MICROCONTROLLER BASED FATIGUE SENSING DEVICES", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.4, Issue 8, page no.657-664, August-2017, Available :http://www.jetir.org/papers/JETIR1708102.pdf

"MICROCONTROLLER BASED FATIGUE SENSING DEVICES", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.4, Issue 8, page no. pp657-664, August-2017, Available at : http://www.jetir.org/papers/JETIR1708102.pdf