Ultrathin Flexible Skin With All-Polyimide Pressure and Airflow Sensor Array for Estimation of Flight Parameters

The estimation of the airspeed and angle of attack (AOA) is crucial for achieving precise flight control in small unmanned aerial vehicles. A flexible skin with distributed flow sensors has been proven to be an effective approach to estimate flight parameters, particularly, pressure-airflow data fusion strategies can improve estimation accuracy. For the first time, we propose an ultrathin ( $70 \mu \text{m}$ ) all-polyimide flexible skin integrated with capacitive pressure sensors and piezoresistive airflow sensors. The ultrathin structure of the flexible skin endows it with flexibility and adaptability to curved airfoils and avoids disturbing the flow field near the surface. Meanwhile, the rational arrangement of the sensors on the leading edge of the airfoil makes them insensitive to the angle of sideslip (AOS). The pressure and airflow sensors achieve a resolution of 4.5 Pa and 2.4 m/s, respectively. Using a simple multilayer perceptron (MLP) neural network, we estimate the average solving errors of airspeed and AOA to be 0.79 m/s and 0.67°, respectively. Compared with traditional methods, the proposed flexible skin considerably reduces the workload by decoupling the airspeed, AOA, and AOS, providing a facile method for efficient and accurate flight parameter estimation.