For drones to be aware of their surroundings and to be able to respond to complex environments, flow sensors can be helpful. Numerous quantitative air flow sensors already exist, but qualitative air flow sensors are less common. Especially sensors equipped to measure quickly changing flows, such as the airflow around flapping flight-based drones. This bachelor assignment aims to design a sensor that is suitable for drones that use flapping flight and measures the quality of the airflow, in particular the presence of flow reversal. The concept of a strain gauge is used to measure the bending of the sensor. The main challenge is to design a strain gauge with a significant change in resistance when the sensor is bent while not making the sensor too stiff.
The latter is because the sensor needs to sense the flow and so the wind needs to bend the sensor and not be significantly affected. The first step was to find the connection between the aeroelastic behaviour and the mechanical properties of the sensor. This was done by testing sensors with different dimensions in a wind tunnel and observing their behaviour. Using these results, ten sensors were designed and tested in a wind tunnel. The product of this research are sensors of which the standard deviation of the resistance is dependent on the direction of airflow. Because of this, the Robotics and Mechatronics work group of the University of Twente can now investigate the airflow around the wings of the Robird better.