Compact Sphere-Shaped Airflow Vector Sensor Based on MEMS Differential Pressure Sensors

Abstract

This paper presents an airflow vector sensor for drones. Drones are expected to play a role in various industrial fields. However, the further improvement of flight stability is a significant issue. In particular, compact drones are more affected by wind during flight. Thus, it is desirable to detect air current directly by an airflow sensor and feedback to the control. In the case of a drone in flight, the sensor should detect wind velocity and direction, particularly in the horizontal direction, for a sudden crosswind. In addition, the sensor must also be small, light, and highly sensitive. Here, we propose a compact spherical airflow sensor for drones. Three highly sensitive microelectromechanical system (MEMS) differential pressure (DP) sensor chips were built in the spherical housing as the sensor elements. The 2D wind direction and velocity can be measured from these sensor elements. The fabricated airflow sensor was attached to a small toy drone. It was demonstrated that the sensor provided an output corresponding to the wind velocity and direction when horizontal wind was applied via a fan while the drone was flying. The experimental results demonstrate that the proposed sensor will be helpful for directly measuring the air current for a drone in flight.

Neural Network-Based Airflow Vector Sensor Using Multiple MEMS Differential Pressure Sensors

“…The root mean square errors of the wind speed and direction, which corresponded to the accuracies, were 0.24 m/s and 3.62°, respectively. It was confirmed that they were substantially improved, because the previous study's fifth order polynomial regression results using the same training/test data set indicate root mean square errors of 0.55 m/s and 6.29° [29]. Although the wind direction intervals and learning methods differed, the root mean square errors for wind speed and direction improved by 56.4% and 42.4%, respectively, in the same order of magnitude as in the simulation.…”

“…The measurements in specific direction regions significantly deteriorate because of this phenomenon [28]. That effects were observed with the compact airflow sensor previously fabricated by our group [29]. Therefore, there is potential for further improvement with regard to the wind direction accuracy.…”

“…The corresponding DP was nearly proportional to the square of the wind speed up to 6 m/s; however, the relationship was almost linear after 7 m/s. This is attributed to the sensitivity of the DP sensor elements [29]. The sensitivity gradually decreases above a certain pressure value.…”

“…We measured the DP of the proposed sensor using simulation software (Ansys Workbench 2022, ANSYS, USA). To evaluate the result of the inlet difference, we also simulated the sensor such that each channel had only central inlets, similar to the previous study [29]. As shown in Figure . 4(a), a rectangular object surrounds the sensor to generate a constant wind speed flow.…”

Needle‐type pressure sensor with silicone oil and parylene membrane inside for minimally invasive measurement

“…The cantilever fabrication process is illustrated in Figure 4C; details are given in a previous study. 21 The cantilever with resistance of the kΩ order was designed to sensitively respond to deformation under pressure of the order of several Pa. 28,29 The thickness of device Si layer, SiO2 layer, and handle Si layer in the SOI wafer was 0.15 , 1.0 , and 300 μm, respectively. First, a piezo layer was formed on the device Si layer.…”