Quality Analysis And Model Optimization Of Scanning Optical Surface In WMPS

As the development of aircraft, ship and other large equipment manufacturingindustry, the requirements for measuring systems with higher efficiency, accuracy andrange is becoming more and more urgent in large-scale metrology field.wMPS(workspace Measuring and Positioning System) is a new type of large-scalelaser measurement method. It provides an effective solution to the problems above,and has turned to a development direction and research hotspot in large-scalemetrology. wMPS achieves intersection measurement of spatial angles with scanningoptical surface, and accuracy of the system depends on the quality of scanning opticalsurface. It has been confirmed in engineering application that the accuracy of thissystem cannot be further improved because under the influence of many aspects thestraightness and stability of scanning optical surface cannot meet the requirements.Analyzing the effects of scanning optical surface to measuring accuracy, discussingthe influencing factors of the quality of scanning optical surface and proposingsolutions to problems above are the major problems of wMPS at present stage. Themain contents of the paper are about quality analysis and model optimization ofscanning optical surface, which includes:1. The measuring models of coordinates and calibration methods to intrinsicparameters in wMPS are analyzed. Based on these analyses, coordinates measuringerror model is established of which the impact of angular error is mainly analyzed.Then the effects to measuring accuracy from both geometrical and intensityparameters of scanning optical surface are analyzed.2. Compositon and structure of the infrared optical masers used to producescanning optical surface are discussed. The factors including laser beam excursion,machining error and assembling error that will affect geometrical shape of scanningoptical surface are explored. With the experiment of light bar acquisition, the fact ofthe light bar’s center line is explored.3. In order to meet the system’s requirement, a new model of scanning opticalsurface, quadric surface equation is proposed instead of plane equation. Based on thetheory of linear least-squares, calculation of parameters in quadric surface equation is discussed. Then, the shape of the surface is discussed. Finally, the evaluationmethodology of surface fitting is proposed.4. With certain experiments, it is proved that quadric surface model is morecloser to the real shape of optical surface than plane model and can decrease error ofinternal parameter effectively.