Design And Performance Synthesis Of Micro-manipulation Stage Based On Response Surface Method

Micro-manipulation stage was widely applied in biological engineering, medical sciences, micro-mechanical manufacturing, aerospace and other frontier fields. Design of micro-manipulation stage with large operational space, fast response speed, high motion precision, and robust performance has important theoretical and practical significance. It is key issue for the research on micro-manipulation stage how to build accurate model which could reflect its performance and to synthesize performance. In the paper, the one-dimensional and three-dimensional micro-manipulation stages were proposed, and its performances were synthesized based on the experimental design and response surface method. The main content is listed as follows:A novel symmetrical micro-manipulation stage with compact structure, large magnification, high natural frequency and motion precision was proposed based on differential lever principle. A design idea of micro-manipulation stage was proposed based on the experimental design method. Firstly, the correlation between displace magnification, natural frequency, motion precision and structure parameters was analyzed by using Latin hypercube sampling, and the structure parameters which had greater impact on performance indexes were obtained. Secondly, the central composite design and response surface method were applied to build the accurate model reflecting the relationship between each performance index and the corresponding structure parameters. Finally, the structure parameters would be obtained by taking each performance index as the object, respectively. The finite element analysis results showed that the proposed idea is effective.A multi-objective optimal design method was proposed based on response surface method. Firstly, the design variables were determined by screening experiment. The simulation experiments data were obtained by using the central composite design. The quadratic polynomials are employed to construct response surface model, which reflects performance indexes of stage, and high fitting degree and high accuracy could be illustrated by the evaluation index 2R 、2abjR andMSEσ. The response surface is the accurate theoretical model for multi-objective optimal design. Finally, the multi-objective genetic algorithm was applied to optimize the stage by taking the displacement magnification and the natural frequency as the object, the strength as the constraint. The results verified the feasibility of design method.Considering the random fluctuations of the stage structure parameters, a reliability-based robust optimization design method was proposed based on 6σ robust design and response surface method. The optimization object of the stage is the robustness of the displacement magnification, the natural frequency and the reliability sensitivity, and its constraint is the strength. Comparing the reliability-based robust with deterministic optimization, the comparison results showed that the variance of the displacement magnification and the natural frequency decrease relative to deterministic optimization, but its mean value is worse, and the reliability of the stage increased from 58.36% to 1. Thus, it meets the design requirements of reliability-based robust optimization.3-PPr and 3-PPs space micro-manipulation stage with three translational degrees of freedom were proposed by combining the one-dimensional stage with parallel four-bar mechanism(Pr) and guiding mechanism(Ps) respectively. The proposed stages have the advantages of compact structure, large magnification, and good decoupling property. An index was proposed which reflected decoupling property. The sequential quadratic programming method was applied to optimize stage by taking the decoupling property as the object, the strength as the constraint based on response method. The result of the optimization showed that the proposed stage had good decoupling property. Comparing the static and dynamic performance of 3-PPr and 3-PPs stage, it can be shown that the flexibility, decoupling property and displacement sensitivity of 3-PPs stage are better than 3-PPr stage, but 3-PPr stage had larger displacement magnification and higher natural frequency.Key Words:micro-manipulation stage; response surface method; multi-objective...