Research On Calibration Of Articulated Coordinate Measuring Machine

Reverse Engineering (RE) as a new designing method can do a lot of things in the absorption domestic and international advanced technique, shortening the product's development period and lowering the production cost. Nowadays articulated coordinate measuring machine(ACMM) is becoming more and more popular in the field of RE and gained great interest from the field of RE, because of its a lot of advantages such as convenience to be used, portability to be carried for its small volume and light weight and flexibility to the worktable. Based on a series of previous researches in this field, a lot of researches on mathematical module and parameter calibration based on newly developed ACMM were carried out as follow in this dissertation.Firstly, the systematic mechanical design about the links and joints for Articulated Coordinate Measuring Machine is discussed. On the basis of D-H method, the mathematical module and movement equation for probing the joint arm end were built; the coordinate transformation equations of the machine were thoroughly inferred and validated. And the verification method was used to simulate the experiment results with the powerful mathematical tool——MATLAB, and therefore the position and posture were simulated. The good agreement of numerical simulation with those of corresponding indicated that the developed model was reasonable and feasible.Secondly, the error model of joints was established, the parameters of joints error were within the extent of permission. The error model was therefore proved true and reliable. Furthermore a new calibration block for calibration was designed. By the aid of a series of analysis with exact differential matrix and least squares method equations, calibration of the structure with high precision was achieved. And the accuracy is expected to reach sub-pixel degree.Finally the articulate arm parameters and coordinate transformation calibration software modules, three independent module—the data recording, calibration calculation and measurement were designed. Compiled with Matlab7.0 and Visual C+ + 6.0, the practicality and universality of the software modules were good. Kinematic analysis and simulation experiment could be realized clearly and vividly in the Pro/MECHANICA module. Simultaneous the rate, geometric acceleration and movement traces of the machine could be also achieved in ACMM, furthermore the interference between components can be judged.