Study On Error Compensation Of Dual-Cantilever 3D CMMS

With the rapid development of modern manufacture technology, 3D-Coordinate Measuring Machines (CMMS) are becoming predominant inspection equipment carrying on the quality control in the manufacturing industry, especially in the automatic production. Fast and high precision probing is the developing trend of CMM. Error compensation has been extensively used to enhance the accuracy of CMM. In this thesis, the error compensation method of a dual-cantilever 3D CMM is discussed in detail.The error compensation model is the key technique in error compensation. According to the structural feature of dual-cantilever 3D CMM, a non-rigid body model is established, which contains additional functions. The theoretical formulas of additional functions are deduced by the analysis of horizontal beam, the vertical column and the carriage. The error compensation model of a dual-cantilever 3D CMM is deduced based on the non-rigid body model.The error motions are measured by the laser interferometer and the electric levels etc. The coefficients of the additional functions can be reckoned by the theoretical knowledge. Hence the error motions related to the additional functions can be derived. The compensation software is drawn up by using the mathematical model and error motions.At last, the effectiveness of this method is tested by measuring liner displacemen- ts along arbitrarily oriented lines through the work zone. The result of measuring approved the effectiveness of the method.