Development Of A Two DOF Motion Error Compensation System

At present, the single point diamond turning technology based on Fast Tool Servo (FTS)has been widely used in machining complex surface, such as optical free surface andmicrostructure surface, and thus considered a potential mechanical processing technology amongengineers and academic circles at home and abroad. In general, the precision of machine toolmotion determines directly the precision of machined surface. In spite of the rapid developmentof CNC machine tool technology can promote the application of FTS turning technology to acertain extent, yet it is still difficult to satisfy the requirement of the precision of the opticalcomplex surface at a nanoscale level. Based on what is mentioned above, this paper, by using atwo degrees freedom of FTS device to compensate motion error of machine tool in processingengineering effectively, improves precision of the machined surface and reduces the FTSdiamond turning technology for the precision requirement of CNC machine tool, which willreduce effectively the degree of complex surface optical manufacturing and improve themachining efficiency. In this paper, the main research content mainly includes the followingseveral aspects:1) Design of a two degrees freedom fast tool servo device with the variable angle in thefront; the job characteristics analysis of Piezoelectric actuators and capacitance displacementsensor, and selection of the appropriate model according to the performance index of FTS device;the design and analysis of structure flexure hinge, Including the design of the flexible hingestructure parameters, the checking of stiffness and strength of performance parameters, theanalysis of input and output displacement, dynamic/static performance analysis, selection ofdiamond cutting tools and so on.2) The flexibility of modeling and finite element simulation of two degrees freedom of FTSdevice. First, by the use of Matrix-based compliance modeling (MCM), the flexibility matrixmodel of FTS device is established, and by using the analysis of ANSYS finite element,components of MCM model are verified; Second, on the basis of Lagrange principle, a dynamicmodel of the FTS device and its natural frequency dependence on structural parameters of therelational model are established, and the analytical results are compared with the finite elementanalysis results, thus the consistency shows that the effectiveness of the established analyticalmodel. 3) The performance testing of two degrees freedom of FTS device; the basic performancetesting of FTS device which is designed under the condition of open loop, such as workingfrequency, motion resolution, maximum performance parameters, other parameters and so on; byusing PMAC controller, two axis servo control system of FTS device is established, and throughthe step response test, the closed-loop response characteristic and cutting tool positioningaccuracy are established.