Dust-resistant microthermal mass-flow pitot-tube for fixed-wing drones (UAV)

Abstract

Drones, commonly referred to as Unmanned Aerial Vehicles (UAVs), have become increasingly important for different applications. For the necessary velocity control, fixed-wing drones typically need a classical Pitot-tube, which consists of several components, including a large sensor which usually has to be calibrated before each flight. The microthermal mass-flow measurement principle enables a smaller sensor design, with less components and no pre-flight calibration. However, the drawback of such sensors is their increased sensitivity to particulate matter contamination. The aim of this paper is to present and test a new additively manufactured Pitot-tube design, which prevents a contamination of the microthermal flow sensor. The results of the particulate matter contamination experiment with the microthermal flow sensor show that the average induced error of 38.3% of the state of the art Pitot-tube design is reduced to 4% for the new additively manufactured Pitot-tube. The results of the flight test show a clear correlation of the differential pressure between the new additively manufactured (AM) Pitot-tube with microthermal flow sensing compared to the standard Pitot-tube design with a membrane sensor. Thus, the new AM Pitot-tube design enables accurate airspeed measurement even in environments with high concentration of particulate matter.