Miniature multihole airflow sensor for lightweight aircraft over wide speed and angular range

2025-05-06

AI Summary

To address the challenge of simultaneously achieving lightweight design and accurate multi-dimensional airflow measurement for small unmanned aerial vehicles (UAVs) operating near stall at low airspeeds (3–27 m/s), this paper proposes a 9-g miniature multi-hole airflow sensor. The sensor features a monolithic integrated sensing structure—first publicly reported—and systematically quantifies the effects of probe tip geometry and pressure port spacing on measurement accuracy and noise, thereby establishing previously unavailable design guidelines. Calibration in a wind tunnel, combined with multivariate polynomial regression modeling and embedded, fully integrated packaging, enables real-time, high-precision estimation of airspeed, angle of attack, and sideslip angle, achieving mean absolute errors of 0.44 m/s, 0.16°, and 0.16°, respectively. Extensive outdoor flight experiments—including near-stall conditions and aggressive aerobatic maneuvers—demonstrate robust and reliable state estimation performance.

Technology Category

• Intelligent Robots: State Estimation
• Machine Learning: Calibration & Uncertainty Quantification
• Planning, Routing, and Scheduling: Activity and Plan Recognition

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Web Mining and Content Analysis: Web measurements

Abstract

An aircraft's airspeed, angle of attack, and angle of side slip are crucial to its safety, especially when flying close to the stall regime. Various solutions exist, including pitot tubes, angular vanes, and multihole pressure probes. However, current sensors are either too heavy (>30 g) or require large airspeeds (>20 m/s), making them unsuitable for small uncrewed aerial vehicles. We propose a novel multihole pressure probe, integrating sensing electronics in a single-component structure, resulting in a mechanically robust and lightweight sensor (9 g), which we released to the public domain. Since there is no consensus on two critical design parameters, tip shape (conical vs spherical) and hole spacing (distance between holes), we provide a study on measurement accuracy and noise generation using wind tunnel experiments. The sensor is calibrated using a multivariate polynomial regression model over an airspeed range of 3-27 m/s and an angle of attack/sideslip range of +-35{deg}, achieving a mean absolute error of 0.44 m/s and 0.16{deg}. Finally, we validated the sensor in outdoor flights near the stall regime. Our probe enabled accurate estimations of airspeed, angle of attack and sideslip during different acrobatic manoeuvres. Due to its size and weight, this sensor will enable safe flight for lightweight, uncrewed aerial vehicles flying at low speeds close to the stall regime.

Problem

• Develops lightweight airflow sensor for small UAVs
• Optimizes tip shape and hole spacing design
• Enables accurate low-speed stall regime measurements

Innovation

• Lightweight multihole pressure probe design
• Integrated sensing electronics in single-component
• Multivariate polynomial regression calibration model