Research On Flexible Measurement Technology Of Geometric Paramatre Of Rotary Body

The rotary type workpieces occupy a large part in aerospace and other fields,and with the support of modern flexible manufacturing technology,their manufacturing accuracy is increasing and the machining surface is expanding from simple cylinders to free-form surfaces.Therefore,the flexible and high precision measurement technology for rotary type workpieces has been a hot topic of research.In this paper,we analyze the principle of flexible measurement and measurement technology for rotary type workpieces,and design a measurement system using the rotary axis reference of rotary workpieces.The main work of this paper is as follows.1)The technical characteristics of the measurement of rotary type workpieces are analyzed.Taking the flexible measurement technology as the starting point,laser triangulation technology is applied to obtain the internal and external diameter point cloud data by laser scanning the surface of the measured part,and the internal and external diameter geometry of the measured part is obtained by calculating the point cloud data based on the conversion relationship between the column coordinate system and the space right angle coordinate system.The measurement system is designed to measure the inner and outer geometry of workpieces with outer diameters from 100 mm to 400 mm and inner diameters from 170 mm to 360 mm.2)The influence of the eccentric tilt error on the measured cross-sectional shape of a rotary type workpiece is analyzed.Using the rotary axis of the rotating body,a data processing method using elliptic direct least squares fitting and spatial linear least squares fitting is established to calculate the axis of the measured part,and the eccentric tilt compensation parameters are inferred from the attitude of the rotary axis of the measured part in the measurement coordinate system to establish the eccentric tilt error compensation matrix to improve the measurement accuracy.3)Analyze and establish the error model of the measurement system,evaluate the error-sensitive direction of the rotary table,propose a calibration scheme to reduce the system error with respect to the installation angle and installation offset distance of the sensor,and verify the reliability of the scheme through simulation experiments.4)The experimental system was designed and the calibration scheme was applied to complete the calibration of the sensor installation error using standard stepped axis sample column,and the error of the rotary diameter measurement result was within ±2 μm,the standard deviation of the diameter measurement was within 3 μm,and the error of the cylindricity measurement result was within ±5 μm.The paper investigates the flexible measurement technology of the workpiece geometry of rotary type,adopts the optical non-contact measurement method,establishes the calculation method of the measured part axis fitting by using the rotary axis characteristics of the rotary body,establishes the compensation matrix for the placement error to reduce the influence on the measurement results,and reduces the influence of the system error on the measurement through the calibration scheme.The feasibility of the calibration scheme and the measurement accuracy of the measurement system are verified.