Research On Kinematic Model And Calibration Of Articulated Coordinate Measuring Machine Based On Local POE Method

The Articulated Coordinate Measuring Machine has been widely applied for assembly robotic calibration et al, which has the merits of wide measuring range, wonderful portability and in-situ measurement. In order to improve the measurement accuracy, the key problems of structure design, mathematic model, error analysis, design of calibration standards and calibration experiment are researched in this thesis. The main works are as follows.(1) The old double support structure of Articulated Coordinate Measuring Machine is optimal by the single support, adding the spring balancer to reduce the labor intensity. According to its new structure, the mathematic model is established by D-H and local frame representation of the product-of-exponentials (Local POE) method, respectively.(2) The main error sources of Articulated Coordinate Measuring Machine are analyzed in details. The influences of each error parameters on the measurement accuracy of Articulated Coordinate Measuring Machine are analyzed comprehensively by Local POE model. Then the priorities of influences of each error parameters on the measurement accuracy of Articulated Coordinate Measuring Machine are obtained by the simulation, which give the guidance significance to its structure optimization, kinematic calibration and error compensation.(3) The length gauges are made by the quartz rod and Invar which both have low coefficient of thermal expansion. So, the quartz rod standard parts and Invar ruler are developed. But the two standard parts can only provide one or two length standard when they are used to measure for Articulated Coordinate Measuring Machine. For the shortage of the two standard parts, dedicated fixture is designed, which can provide measurement of multi position and multi pose.(4) Based on the analysis of the Gauss-Newton algorithm which will introduce the operational errors when be used in calibration, the particle swarm algorithm is proposed as the calibration algorithm of Articulated Coordinate Measuring Machine in this thesis and used to calibrate the measuring machine. Then the obtained optimal parameters will be threw back to the original model to modify structure parameters. Finally, the experiment verification is adopted.