The Modeling And Simulation For Coordinate Measuring Of Complex Surface In Reverse Engineering

According as the constant satisfactory and development of the technology of reverse engineering, the porpuse of complex curved surface measurement is not only limited to gain and estimate the quality indicator of curved surface measured, but more importment is the numeral measurement of the part model surface As during the process of reverse engineering, in order to reconformate precisively CAD model of the object, for the first, the splashes which could reflect the characteristcs of sampling curved surface should be drawed, and then make pretreatment process for measurement data. Under the subsidize of Gansu Natural Science Fund, this thesis made the research of the coordination measurement method of curved surface during reverse engineering, which provided a theoretical method for the adaptive measurement of complex curved surface.Based on the existing results that theoretical knowledge and complex curved surface measure method of reverse engineering, through comparing advantages and disadvantages of currently various numeral methods, the three coordinate machine(CMM) was chosed as the numeral equipments. And based on the obtain of the key technique of splashes data in the CMM, the problem of measurement process in how to carry out to measure point of adaptive distribution was mainly studied, in order to carry out a measure data accuratedly and efficiently, namely under the sistuation that can be correct to mean product characteristic, the data collection is as far as possible little and walk through of the path is as far as possible short and time cost is as far as possible little.According to the characteristics of contact measurement, in order to raise the measure efficiency of the measure machine, carry out complex curved surface parts of fast automation measurement, two times sample method which was basing on the sample according to the ash and combine together according to the whole sample of shape characteristic was put forward, which made the unknown curved surface bacome known curved surface, thus carry on measurement just for the key characteristic points, and the problem of failure following because of more picking points was overcomed.Considering the problem that handle measurement has lower efficiency and bigger error, the mathematics model of auto following that measure characteristic's point was put forward and built up which based on ash predict theory, the result express that the model can carry out free curved surface to measure point of distribute measure from the orientation; For the problem that all present measurement distribute methods are static, and could not describe the curved face shape's information accurately, at whole sample, according to object 3D center of gravity thought, a measurement point dynamic adaptive distributional model was put forward, which was based on shape characteristic, and it made measurement point distribution more reasonable. In the UG, the simulation was made for the measure path, which could help avoid collision while measuring.Against the different characteristics of Scattered data and scanning lines data, the merging multiple view points cloud, smoothing treatment, probe radius compensation, and other key issues in the pretreatment process of measurement data were studied respectively, and a part of procedure of the pretreatment process of data was compiled, which created an advantaged condition for the following model reconformation.