Flow separation sensing on airfoil using a 3D printed biomimetic artificial hair sensor

Abstract

Small-scale unmanned air vehicles require lightweight, compact, and low-power sensors that encompass a variety of sensing modalities to enable flight control and navigation in challenging environments. Flow sensing is one such modality that has attracted much interest in recent years. In this paper, a micro-scale artificial hair sensor is developed to resolve both the direction and magnitude of airflow. The sensor structure employs a high-aspect ratio hair structure and a thin flexible membrane to facilitate the transduction of directional airflow to membrane deflection. The sensor readout is based on capacitive sensing and two pairs of electrodes orthogonal to each other are used to obtain airflow directional information. The sensor structure was fabricated by using two photon polymerization and integrated onto a miniature printed circuit board to enable simple measurement. The sensor’s responses to static displacement loading from different directions were characterized. The experimental results are in good agreement with the simulation results. Furthermore, the sensor’s capability to measure the direction and magnitude of flow was demonstrated. Finally, the sensor was mounted on an airfoil and its ability to detect flow separation was verified.

3D‐Printed Electrostatic Microactuators for Flexible Microsystems

“…Sensors that require electrically conductive materials can also be printed on these FPCBs. For example, the electrostatic microactuators in this work could instead be used as capacitive sensors to detect rotation, and other novel capacitive sensing architectures could also be used (e.g., [ 42 ] ). By leveraging the integration capability of the FPCB through embedded metal layers, untethered flexible microsystems with on‐board electronics will open up a pathway toward smart flexible microsystems with power and control autonomy.…”

Bio-inspired, sensitivity-enhanced, bi-directional airflow sensor for turbulence detection

“…These structures include hair-like appendages added to the substrates or bending beam structures induced by residual stresses. [9][10][11][12][13][14][15][16][17][18] However, the complex fabrication processes and intricate devices make these approaches impractical for large-scale production. Moreover, the inconsistent response of bending beams to forward and backward airflow results in low sensor sensitivity.…”

Actuation-enhanced multifunctional sensing and information recognition by magnetic artificial cilia arrays

“…In biological systems, motile cilia can efficiently pump fluids at low Reynolds ( Re ) numbers, while primary cilia cannot actively manipulate fluid but exhibit mechanosensory and chemosensory functions ( 7 ). Inspired by the active motions and sensing functions of biological cilia, small-scale cilia-like devices as actuators and sensors, which can manipulate fluids or sense the fluid properties in narrow spaces, show great potential in microfluidics ( 8 , 9 ), biomechanics ( 10 ), biomedical engineering ( 11 ), and flow detection ( 12 ). For example, integrating flexible sensors into miniature devices ( 13 , 14 ) could potentially enable physical intelligence ( 15 ) by allowing adaptive behaviors in dynamic, complex, and fluid-filled confined environments using in situ feedback of the environmental cues.…”