Knowledge Bank

Lightweight air vehicles such as drones, kites, and weather balloons require active wind monitoring devices for flight control. However, current aircraft wind monitoring devices such as cup anemometers, pitot tubes, and radiosondes tend to be large and heavy. As a result, they induce aerodynamic drag and often require additional power draw, reducing the aircraft's efficiency. To address these problems, a lightweight, self-powered wind sensor was developed for aircraft applications. In the first phase of this project, capacitive sensors and a magnetometer were integrated in an airfoil for wind speed and direction measurements. In the second phase, a wind energy harvesting subsystem was developed using Metglas, which is a magnetostrictive material that produces a magnetic field change when stressed. This change in magnetic field can be converted into electrical energy based on Faraday's law that states, a voltage is induced in a coil exposed to a changing magnetic field. Metglas is a desirable material for energy conversion due to its strength and long cycle life. To better understand this material, unannealed Metglas 2826MB and Metglas 2605SA1 were placed in a clamped, cantilever beam setup. The resonant frequencies of the beam were determined both analytically and experimentally to find optimal vibration for power output. Vibrations were induced in the beam with a shaker and the output voltage produced was observed through a copper coil wrapped around the beam. In this setup, a Metglas/steel unimorph beam was proven to have energy conversion capabilities. Results from this study will help better understand vibrational power potential of all forms of Metglas, specifically unannealed variations. Knowing more of its controlled vibrational behavior can help to predict its power generation from vibrations due to wind or other sources, allowing it to be used for a variety of low power applications.