| Optical free-form surface is called as non-rotationally symmetric optical surface,it’s English name is Non-Rotational Symmetric Surfaces, and NRS surface for short.As the optical free surface widely used in the aerospace, the field of civil and militaryindustry, people want more and more in a more simple and economical, reliable andefficient way to obtain high quality optical free curved surface. The subject study on a longstroke which meet the actual needs, after contrasting the research of scholars both at home andabroad, decide was made to design a new type of two degree of freedom FTS. Thedriving device is voice coil motor, the guide device. is the combination of flexurehinge and rolling guide. The flexible hinge is designed to "X" form, under the premisethat guaranteed its own strength and increases the stroke. Adopting double flexiblehinges greatly increased its lateral stiffness, effectively solve the problem of cuttingtool’s tremor. The design of the v-shaped rail increase the stroke, and make the twodegrees of freedom movement completely decoupled, but its strict machiningprecision and complicated assembly have brought certain difficulties to its application.Detecting element and the displacement feedback device adopts straight line gratingdisplacement sensor. The main research content is as follows：1. Under the precondition of consulting a large number of literature, todiscussing the practical problems of FTS cutting, to get the conclusion that the designof two degrees of freedom FTS is necessary and superior.2. Completing the structural design of two degrees of freedom FTS. Maincontents include the overall design of a two degrees of freedom FTS device, linearmotor’s selection, the selection of linear grating sensors, the calculation and design ofthe X direction’s flexure hinge, the calculation and design of the Z direction’s rollingguide, finally, the parts design of feedback element.3. Completing the two degrees of freedom FTS device’s ANSYS analysis. Maincontent includes: stress and stiffness analysis of statics and dynamics of the modalanalysis, and establish the mechanism of system control function. Use the function to do step response with MATLAB software.4. Making use of detection system to analysis the performance of FTS which hascompleted assembly. Mainly includes: the stiffness measurement of the Z direction’srolling guide, two degree of freedom system’s crosstalk, step response, motionresolution measurement and sine trajectory tracking ability.Compared with other known FTS device, the designed device has the followingadvantages: with500microns processing range, belong to the large stroke FTS; in theguide using the flexible hinge combined with rolling guide, solve the one-piece twodegrees of freedom of flexible hinge’s crosstalk problem; at the same time, in the caseof guarantee processing requirements, the device’s movement can reach20Hzfrequency. |
