Calibration Of 3D Measurement System For Aero Compressor Blade Based On Polunomial Fitting Method

With the development of our country’s economy,the number of aviation aircraft is increasing gradually by years.At the same time the number of air vehicle for maintenance is increasing.So the aircraft maintenance industry will be very promising.Aviation aircraft engine blade is the key components of the aircraft.However due to the complex appearance,special working environment and expensive manufacturing costs,the blade’s manufacturing played significant property in the aspect of aviation engine maintenance value,and the potential value will a be paid more attention.This phenomenon urges us to develop a kind of precise,fast and automated welding repair equipment with independent intellectual property rights of our country.In process of blade maintenance we should make use of blade’s three-dimension point-cloud data to plan blade’s welding trajectory and make necessary measure.So the research of three-dimension point-cloud data access technology has important significance.In order to avoid the spread of the hardware installation error,establish measure system model of removing parallel constraint.Based on the analysis of the influence of camera lens distortion on the measurement accuracy of the system,the polynomial fitting system calibration method will be used to fit the relationship between the absolute phase and the height of the object to be measured.In order to reduce the non-linear error introduced by oblique projected uniform stripes,we put forward a kind of non-uniform stripe generated method which is appropriate for non-complete constraint model.According to the problem of the dual-frequency heterodyne phase unwrapping method’s limitation for projection fringe frequency could reduce the capability of system detail measurement,we put forward a kind of non-uniform stripe phase unwrapping algorithm.This method could not only lift restriction of dual-band heterodyne non-uniform stripe phase unwrapping algorithm on projection fringe frequency but also improve the ability of the measuring system for detail.On the premise of non-uniform fringe projection,we make simulation experiment for cube and arch object.Compare binary space-time coding phase unwrapping method combined with removing parallel constraint system measurement results with double-frequency heterodyne phase unwrapping combined with full restraint system of measuring results,the reduced amount of average and standard deviation for cube object are 95% and 90% respectively.The reduced amount of average and standard deviation of arch object are 65% and 51% respectively.So this method could increase the accuracy of measurement obviously.Through using the established contacted removing parallel constraint system to measure the sixth level blade of aero engine,we could get precise blade’s three-dimensional point-cloud data.Eventually compared with blade’s three key data’s actual values and measured values: the most height value,width value and thickness value.The above three parameters’ predicted maximum deviation are 0.075%,0.050% and 2.4% respectively.