In flight testing, precise time synchronization significantly influences the accuracy of test results. For critical applications such as data acquisition in airborne test equipment, accurate timing is fundamental to the reliable operation of flight test systems and the precision of test data. The IRIG (Inter-Range Instrumentation Group) standards for IRIG_B codes, established by the International Radio Consultative Committee, enhance the efficiency and reliability of time synchronization among different systems by defining methods and accuracy requirements for unified time synchronization. Despite existing research making strides in improving IRIG_B code demodulation performance, traditional techniques still encounter timing inaccuracies under extreme conditions. To address these challenges, this paper proposes a design solution for second pulse delay timing, presenting a detailed process for AC IRIG_B code demodulation. Experimental results validate the effectiveness and accuracy of this approach in generating and demodulating time information.
The application of Structural Health Monitoring (SHM) in international aviation has evolved from its initial focus on monitoring aircraft structural loads to encompassing damage detection, localization, and structural lifespan prediction. Traditional systems face challenges such as complex cable arrangements and limitations imposed by battery life and replacement difficulties. In response, this study explores a novel approach using vibration energy harvesting (VEH) to power helicopter SHM systems. By leveraging piezoelectric materials and VEH technology, we designed a miniature vibration energy harvester based on the key piezoelectric material Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT). Finite element simulations and experimental validations demonstrate stable performance of the system under varying temperatures and accelerations, showcasing its potential reliability in practical applications. This research not only contributes technical insights for the development of Helicopter Health and Usage Monitoring Systems (HUMS) but also underscores the significant potential of vibration energy harvesting technology in enhancing energy sustainability.
This paper introduces the importance of airborne strain testing and the limitations of existing methods. To address the problem of traditional contact measurement that may affect the test position and installation, an airborne strain measurement method based on digital speckle images is proposed. This method utilizes an optical measurement system and image processing algorithm to calculate the strain value, which has the advantages of non-contact and high precision. The maximum value of non-linearity error for this measurement method is 0.56%, a reduction of 5.1% compared to the conventional measurement method. The application of this technology will help improve the safety and economy of aircraft.
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