Study On The Key Technologies Of 3D Laser Scanner In The Online Large And Hot Forging Detection

As the key parts of major based equipments and heavy manufacturing equipments, large forgings are widely applied to electric power, military industry, chemical industry, transportation, shipbuilding industry, and play an important role in many aspects of national economy. Large forgings mostly use the free forging processing method, in the process, energy consumption is huge, and results in large cost. As the key link of quality testing and feedback of control, the geometrical size detection becomes more prominent. The paper combines the urgent need of high-quality large forgings from the state's major industries, according to the internal backward situation, with the subject under funded by national major projects subject, we introduce the 3d laser scanning technology into the large and hot forging survey field, and aim to develop the online detection device with independent intellectual property rights, suitable for the forging process of hot forgings, hoping to make a contribution to improving manufacturing level of large forgings. The main work can be detailed as follows:1. The working principle of the pulse scanning is expatiated, the software and hardware systems of the laser scanning system for the online large and hot forging detection are introduced, and the plan, detailed implementation method and data assessment process for online detection with the device are designed.2. A study on the error sources of pulsed laser scanner is presented, and several bigger error factors influencing the measuring precision are mainly analyzed. Learning from the calibration model of total station, calibration methods for system errors, based on the modular model, are designed, applying the three-stage method, horizontal sequence mark method and vertical sequence mark method to calibrating and correcting the ranging additive constant, horizontal angle error and vertical angle error of GLS-1500 respectively, and the effect of the mark center extraction accuracy on the calibration result is analyzed in the angle calibration experiments.3. Learning from self-check calibration model of camera parameters in photogrammetry, referring to the application experience in self-check calibration method of the laser scanner abroad, an indoor self-check calibration field, based on the control points, is designed, with the self-check calibration experiment of GLS-1500, the method is validated feasible, and through the significance test, the advice for optimizing parameters structure is provided.4. The method of scanning range control for non-coaxial camera is put forward, the position between the laser scanner and the camera is realized with the calibration of inside parameters with test range and external parameters with DLT respectively. By the way, the process of scanning range control based on the image is induced, and the method is validated feasible with an experiment. 5. The point cloud data processing technology is briefly reviewed, the memory mapping file technology is applied to realize the rapid read of massive data, interactive tools for deleting noise points are achieved and maximum connected domain point cloud extracting method is carried out. With the comparative analysis between the axis extraction methods currently, realize the axis extraction of the forging based on the normal gaussian image, on which basis, we introduce the LM optimum arithmetic to calculate the size of cylinder and cone. Finally, the method is validated feasibily and reliabily with computer simulation data and real model data, and through the analysis of error sources, finally, a preliminary correction model is given.6. Software is programmed, functional modules, such as date process, are carried out. At the end, with the software, a process of real point cloud date from cylinder is shown.