{'fraction_non_alphanumeric': 0.02248062015503876, 'fraction_numerical': 0.003875968992248062, 'mean_word_length': 5.297560975609756, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
New photoelectric method for inside cylindricity measurement

Cylindricity is an important parameter in the evaluation for a cylindraceous workpiece. It has a direct effect on the precision of assembly and rotation. However it is difficult to carry out inside cylindricity measurement for a large workpiece (length: 2~3m, diameter >200mm), in which the spindle's straightness and measuring table's motion error deserve consideration. In this paper, a new error separation method is presented based on the application of precise photoelectric inspecting technique. And the two errors will be directly measured according to the deviation of facula. During the measurement, the workpiece is installed erectly on the base to minimize its distortion. Laser collimation initializes the measuring needle and gives real-time state of the measuring table. Two kinds of coordinates are used for error compensation, i.e. absolute and imaging coordinates. In the end, the least squares cylinder is used to calculate the cylindricity after all point data of each section are modified. Overall structure design and detailed measuring steps are also listed. Thus, the models of error compensation and cylindricity evaluation are obtained. Simulation results prove them correct with a satisfying precision.