Research On Three-dimensional Measurement Method Of Aeroengine Blades Based On Combined Structured Light

Aeroengines are one of the key components of aircraft.The measurement for the three-dimensional shape of the blades directly affects the production processing of aeroengine and the overall energy of the aeroengine.With the continuous development of computer technology and image processing technology,the rapid and accurate acquisition of three-dimensional surface of aeroengine blades with optical technology is an important research field in the measurement of aeroengine blades.It can be applied to the production of aeroengine blades and reversr engineering.The existing stripes projection three-dimensional measurement method has high measuring accuracy,but it can not be used for the case where the initial point for phase unwrapping isn't fixed on non-continuous surface.In order to solve the above problems,this paper presents a three-dimensional measurement method of the combination of fringe projection three-dimensional measurement method and binocular stereo vision.The three-dimensional measurement system is designed and constructed.The experimental results show that the method is effective.The main research work includes:1 The three-dimensional measurement methods of the existing aero-engine blades are studied,and the important role of the three-dimensional information measurement in production and maintenance is pointed out.This paper introduces and compares several kinds of three-dimensional measurement methods,especially the classification and introduction of machine vision.This paper analyzes the advantages and disadvantages of different methods,and puts forward a new method of combined structured light three-dimensional measurement based on active binocular vision and fringe projection measurement.2 The three-dimensional measurement system of combined structure light is designed and built.The work mainly includes the selection of the hardware,the construction of the combination of structured light three-dimensional measurement system and the software design.The hardware is composed of a mechanical clamping structure,an image acquisition module,a motion control module and a structured light projection module.Software part is developped based on LabVIEW programming language and integration MATLAB.3 The combined structure light three dimentional reconstruction system are calibrated,including camera noise,camera internal and external parameters,binocular stereo vision,projector,fringe projection system and the axis of rotation.4 A new phase unwrapping algorithm based on active binocular vision is proposed by combining the fringe projection measurement method and binocular stereo vision measurement method.The series of deformation fringes are projected on the object and the pictures are identified by active binocular vision,and the phase unwrapping process is solved.5 The proposed method is validated by experiments.The inlet guide vane and the turbine blade are measured.The experimental results verify the correctness and effectiveness of the proposed method.