Cmm Profile Of The Complex Curves And Surfaces Adaptive Evaluation Methods And Software Development,

CNC Coordinate measuring machines(CMM) are necessary measuringdevices in the modern manufacturing system. Developing mating software of CMMthat used to measuring and evaluting parts of profile with complicated andirregular surface accurtely is the one of the important projects all the time in thefield of geometrical metrology.First,in this paper,from the view of actual application and combined with thecharacteristic of CMM,the mathematical modles of free curve and surface are setup by the interpolating B-spline fitting method. Then the set of real points onmeasured profile is obtained with high precision through the probe radiuscompensation based on the principle that the trace of the center of the ball-shapedis the offset curve(surface) of the curve(surface) measured. Finally,after anaccurate method for calculating the normal distance from a measring point to thetheoretical profile is deduced, an optimum algorithm is introduced to evalute thereal profile error.Its distinguishing characteristic is that the position of measuredprofile can be adjusted automatically to adapt to an ideal profile by iterativeoptimization until precision meet our needs during data processing. Also thealogrithm for Circularity evalution is presented.The above seheme have been debugged and runs steadily,the results areaccurate and reliable.