In-flight measurement method and application research of helicopter rotor blade motion parameters

Accurate measurement of helicopter rotor motion parameters (flap, lead-lag, torsion, and azimuth angles) is essential for rotor blade design, helicopter dynamics modeling, and flight safety and health monitoring. However, the existing methods face challenges in testing equipment installation, calibration, and data transmission, resulting in limited reports on real-time in-flight measurements of blade motion parameters. This paper proposes a non-contact optoelectronic method based on two-dimensional position-sensitive detectors for in-flight measurement and a ground calibration system to obtain real-time rotor motion parameters during helicopter flight. The proposed method establishes the time evolution relationship of rotor motion parameters and verifies the performance of the in-flight measurement system regarding measurement resolution and accuracy through the construction of a blade motion posture experimental platform. The proposed method has been applied to the flight measurement of a medium-sized single-rotor helicopter, and the obtained results have been compared with theoretical analysis outcomes. Furthermore, this paper examines the characteristics of blade motion parameters during flight and discusses the challenges and potential solutions for measuring rotor motion parameters during helicopter flight using the proposed method.