As demand for autonomous aircraft increases, better wind sensors - anemometers - are needed to make it easier for these vehicles to sense weather changes and perform safer take-offs and landings, according to researchers.
Such enhancements could improve how people use their local airspace, through drones delivering packages or passengers one day flying on unmanned aircraft, said Marcelo Dapino, co-author of the study and a professor in mechanical and aerospace engineering at The Ohio State University. The team’s research is published in Frontiers in Materials.
“Our ability to use the airspace to move or transport things in an efficient manner has huge societal implications,” Dapino said in a statement. “But to operate these flying objects, precise wind measurements must be available in real time whether the vehicle is manned or unmanned.”
Besides helping aerial objects cross long distances, accurate wind measurements are also important for energy forecasting and optimising the performance of wind turbines, he said.
Leon Headings, co-author of the study and a senior research associate in mechanical and aerospace engineering at Ohio State, said the instrument was fabricated from smart materials. The team used polyvinylidene fluoride (PVDF), which has piezoelectric properties that can power the device. The measured voltage or change in capacitance of a piece of flexible PVDF film can be correlated to the wind speed.
The PVDF sensor is incorporated into an airfoil, which reduces aerodynamic drag. Because the airfoil is free to rotate, it can be used to measure the direction of the wind.
To test their device the researchers designed a two-pronged experiment. The pressure sensor was first tested in a sealed chamber to determine its sensitivity. The sensor was then incorporated into an airfoil and tested in a wind tunnel. The results showed that the sensor measures pressure and wind speed extremely well. A small digital magnetometer compass integrated into the airfoil provides precise wind direction data by measuring the absolute orientation of the airfoil relative to the Earth’s magnetic field.
More research needs to be done to move the wind sensor concept from a controlled research environment to commercial applications. As his team continues to work with PVDF and other advanced materials to improve sensor technology, Dapino hopes that their work will eventually lead to technology that can be used outside of aircraft, such as for wind turbines.
“These are very advanced materials and they can be used in many applications,” said Dapino. “We would like to build on those applications to bring compact wind energy generation to the home.”