Research On Measurement Technology Of Wind Turbine Blade Based On Binocular Structured Light

Wind turbine blade is an important part of wind turbines,and the reliability of its manufacturing quality directly determines the operation status of wind turbine.At present,the factory only relies on the accuracy of the mold and manual experience to judge the quality of wind turbine blades,and lacks an effective measurement method.At the same time,in order to solve the problems of harsh working environment,low processing efficiency and unstable quality in the process of manual grinding of wind turbine blades,robotic automatic production line is used to grind,which needs to obtain the actual three-dimensional information of wind turbine blades to guide the processing and production of the blades.The difficulty of wind turbine blade measurement lies in its complex shape and large size.Based on these current situation and problems,this paper proposes a measurement method for large-scale workpieces such as wind turbine blades.In order to achieve high-speed,high-precision and low-cost measurement,a binocular structured-light vision measurement platform is built,and multi-angle measurement is carried out using robot information.The main work is:Firstly,the geometric imaging model and calibration mathematical principle of the camera are analyzed.Based on the plane target,the calibration experiments of the camera's internal and external parameters are carried out,and the experimental results are analyzed.Then,the existing structured light coding and decoding methods are analyzed and their advantages and disadvantages are compared.The four-step phase-shifting method is used to calculate the wrapped phase value.And the unwrapped phase value is calculated by multi-frequency hierarchical method.The problem of frequency selection in multi-frequency hierarchical method is illustrated through experiments,and the accuracy of the algorithm is verified.Next,a fast binocular stereo matching method based on the combination of extreme slope and absolute phase is proposed,and the three-dimensional coordinates of the object are obtained by combining the principle of triangulation.Then,aiming at the measurement problems and processing status of wind turbine blades,the robot-driven measuring equipment is used to scan many times,and rough stitching is realized based on robot coordinates and hand-eye calibration.Then,combined with ICP precision stitching method,the error is corrected to improve the accuracy,so as to realize the complete three-dimensional profile measurement of large wind turbine blades.Finally,using the binocular structured light three-dimensional measurement platform built in this paper,the accuracy of the binocular structured light measurement equipment is verified by the three-dimensional measurement experiment of a flat plate and a standard sphere under a single view.The three-dimensional measurement experiment of the standard sphere under multiple views is carried out,which verifies the accuracy of the whole three-dimensional measurement system combined with the robot.The wind turbine blade measurement experiment proves the feasibility of the measurement method proposed in this paper.