Measuring Point Planning and Fitting Optimization of the Flange and Spigot Structures of Aeroengine Rotors

An optimized measuring point planning and fitting method for rotor flange and spigot structures was proposed to achieve precise measurement of position and pose of the aeroengine rotors during docking processes. Firstly, the impact of circumferential phase angle, distribution range angle, total number of measuring points, and number of distribution rings on measurement uncertainty was analyzed. The measuring point planning schemes for flange and spigot were proposed. Secondly, the Gauss Newton iterative solution principle considering damping factors was clarified. Subsequently, an optimized iterative reweighting method consisting of weight iterative estimation, singular value detection under the Chauvenet criterion, and clustering detection was proposed for fitting the flange annular end face. A mapping point total least squares method with practical geometric significance was proposed for fitting the spigot cylinder face. Finally, measuring and fitting experiments were performed. The singular measuring point detection methods were verified. Under the optimized fitting methods, the goodness of fit and average orthogonal distance of flange and spigot structures are 0.756 and 0.089 mm, respectively, which have higher fitting accuracy than the other traditional methods.