Research on the measurement method of the torsion angle of the blade root of the coaxial helicopter

Aiming at the problem that the traditional torsion angle calculation method does not consider the influence of non-coplanar marking points caused by blade waving during high-speed rotor rotation, which makes the measurement results have large errors, and the measurement method of pasting marking points on the blade surface is not applicable to the propeller of dual-rotor models, a coaxial dual-rotor helicopter blade torsion angle measurement method based on binocular vision is proposed. First, fix the marker point vertically under the blade, and place the binocular camera facing the hub; secondly, collect the reference image of the marker point when the blade is flattened at a low speed and the twist image of the azimuth marker point to be measured when the blade rotates at high speed, and according to the reference image The three-dimensional coordinates of the marked points are used for plane fitting; finally, the torsion image marked points are projected on the plane, and the angle between the two three-dimensional vectors in the plane is obtained as the blade twist angle.