| The articulated arm flexible CMM studied in this thesis is one kind of knuckle-type CMMs. In articulated arm flexible CMM, high-accuracy angle measuring sensors are utilized to measure the rotation angles of knuckles, and the center coordinates of gauge head are calculated through coordinate transformation. Articulated arm flexible CMM has many advantages such as simplicity in structure, wide measuring range, small volume and low cost. It is convenient to setup on site in production line, easy to operate and portable, and have very wide prospective application. There is no own reseach articulated arm CMM produced in China, so the current domestic market price of the Articulated Arm CMMs is very high. Therefore it is very significant for filling the gaps in domestic, saving costs of equipment import costs and developing the new types of flexible CMM that accelerate research of the articulated arm flexible CMM.This project is financially supported by National Natural Science Foundation of China, the number is 50475116. The following work has being done in this project:1. By using Denavit-Hartenberg analysis arithmetic, the ideal mathematical model and error model of the articulated arm CMM are established. All error sources are deeply analyzed according to the traits of the system.2. Based on the D-H method, set up complex ball coordinate system and establish a new and simpler math model. Designed parameters calibration method.3. Verified the feasibility and accuracy of the calibration method, by calibrating the Faro Platinum 1.2m Arm CMM. Summed up the problem in the process of calibration. Accumulated the practical experience for research of the own Arm CMM calibration.4. An improved genetic algorithm, which adopts real coding, an arithmetic crossover operator, a gauss mutation operator, adaptive mutation probability and a modified elitist strategy are deduced. Through the simulations, the effectiveness of the Arm CMM probe's calibration is proved. |
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