Study On Topology Optimization Design Of A MEMS Piezoeletric Microactuator In Horizontal-plane

Topology optimization is one of the front subjects in structure optimization field, the structure which is optimized by toplogy optimization has many advantages such as less usage of material, weight reduction, the most important aspect is the performance can gain a great enhancement, then can bring direct economic benefit and shorten development cycle of new productions, so the study on topology has become a hotspot in recent years. But the study of structural optimization design of microactuator almost adopts traditional design methods, it depends on the experience and instinct to a great extent and is lack of innovated and effective structural theory guidance.In this paper the driving mechanisim and principle of the microactuator were analysised, the piezoelectric coupling was simulated, the relationship between key parameter dimensions and output characteristic was obtained by using sizing optimiztion method, the optimal parameter dimensions combination was obtained after optimization.The mathematical model was established based on SIMP material interpolation, the output displacement of y-direction was chosen as objective function and different volume fractions as constraint functions, different topological structures were obtained with different volume fractions constraints, the best topology optimization result was obtained with the volume fraction 0.3 upper, and the topological structure is manufacturable. Then integral rigidity was chosen as objective function, the topology structure with largest integral stiffness was obtained after topology optimization.To meet the multiple performance requirements, integrated multiple objectives topology optimization model was established, both the output displacement of y-direction and integral stiffness, the output displacement and output driving force can be taken into account. Different topology shapes are presented with the important degree of different performances. Further more, to improve the horizontal output characteristic, the output displacement of z-direction must be constrainted effectively when purchasing output y-direction displacement, so the multiple objective optimization integrated function was established which both the output displacement of y-direction and z-direction were taken into account, the output dispacement of z-direction is constrainted effectively after topology optimization, the output horizontal characteristic of MEMS microactuator is obviously improved.The technological processes of optimized result were designed, wet etching of PZT, silicon deep etching processes were introduced in detail.