Modeling and Optimal Design of Planar Linkage Mechanism of Coupled Joint Clearances for Manufacturing

The uncertainty of the mechanism motion error is mostly caused by the manufacturing process,so the motion error cannot be effectively predicted at the design phase.The problems of manufacturing complexity and the relationship between design and manufacturing are analyzed,and the influence of dimensional tolerance and fit tolerance on the motion accuracy of the system is considered in the design process.Then based on the Monte Carlo simulation,an optimal design model of planar linkage mechanism is set up.A typical offset slider-crank mechanism is used as an illustrative example to carry out the optimal design.Compared with the result of typical robustness design,the similar variation characteristics of the mean value and the standard deviation can be found,so the proposed method is effective.The method is furthermore applied in the optimization of the schemes with different fit tolerances and the prediction of motion errors in the design phase is achieved.A set of quantitative evaluation system for mechanism optimal design is provided.Finally,a basic strategy is presented to balance the motion precision and manufacturing cost.

Manufacture tolerance analysis and control for a polymer-on-silicon Mach-Zehnder-interferometer-based electro-optic switch

To enhance the electro-optic (EO) modulation efficiency and realize the impedance-matching, a polymer-on-silicon multi-mode interference (MMI) Mach-Zehnder interferometer (MZI)-based electro-optic (EO) switch is designed and optimized. Under the central operation wavelength of 1550 nm, the driving voltages of the designed switch are 0 and ±1.375 V, respectively, with a short active region length of 5 mm, and the characteristic impedance of the electrode is about 49.6 ?. The manufacture tolerance is analyzed for instructing the device fabrication. The results show that to realize ideal switching function, high fabrication accuracy on the buffer thickness, core thickness, electrode width and MMI waveguide width is extremely required, and a small voltage drift of-0.03-0.05 V is also expected for reducing the crosstalk to less than-30 dB. The allowed 3 dB bandwidth is 60 nm, and within this spectrum range, the insertion loss and crosstalk are less than 6.71 dB and-30 dB, respectively.

A laser beam shaper for homogeneous rectangular illumination based on freeform micro lens array

An effective design method of freeform micro lens array is presented for shaping varied laser beams into prescribed rectangular illumination. The variable separation mapping is applied to design concave freeform surfaces for constructing a freeform lens array. Several dedicated examples show that the designed freeform optical lens array can achieve a prescribed rectangular illumination pattern, especially without considering the initial states of incident laser beams. Both high collection efficiency and good spatial uniformity can be available simultaneously. Tolerance analysis is also performed to demonstrate that this optical device can well avoid fabricating difficulty in actual applications.