The Static And Dynamic Analysis Of Micro-assembly System For Non-silicon MEMS Devices

Non-silicon MEMS devices have the characteristics of small volume, light weight, easy damage,difficult assembly. At present, the assembly mainly relies on manual or semi-automatic assembly, whichgreatly reduces the efficiency and quality of the work, so, it is important for studying the automaticassembly technology and equipment of non-silicon MEMS devices. Our team developed the firstdomestic flexible automatic micro-assembly system for non-silicon MEMS devices. In order to ensurethe accuracy and stability of the micro-assembly system, this pape studies the static and dynamicanalysis of the micro-assembly system. The main contents are as follows:(1) In order to figure out the influence of the static deformation on the assembling precision of themicro-assembly system, the static characteristics analysis of it was made. Firstly, a3-D model was built,and the infinite element analysis was taken to study the whole static characteristic of the microassemblysystem. It was proved that the system had good rigidity for overall structure. In addition, allowing for theassembling feature and assembling method for the non-silicon assembled parts, infinite element analysiswas made for the weaker region of the micro-assembly system. The influence on the assemblingprecision made by the weaker region’s deformation was calculated from the infinite element analysisresult.(2) Combined with the static deformation of micro-assembly system and the analysis of assemblyprecision, the assembly errors were carried out. Firstly, the impact mechanism for non-silicon MEMSdevices assembly of the components of micro-assembly system was analyzed, excluding irrelevant orless affected parts, focusing on the influence of the assembly unit on the system assembly precision.Then, for assembly unit, the error sources which affect the assembly of non-silicon MEMS devices in theassembly unit were analyzed, excluding compensation term in the sources of error. For the remainingerror sources, specific error values were measured through experiments. Establish theoretical errorpropagation model to calculate the corresponding error domain, and ultimately get the maximumassembly error value of micro-assembly system. Finally, the correctness of the above theory is provedthrough the assembly precision validation experiments.(3) In order to avoid the low frequency resonance region and ensure the stability of assemblysystem, the dynamic analysis of t micro-assembly system was carried out. Firstly, the finite elementmodal analysis of micro-assembly system was built. On the basis of the modal analysis results, the main factor affecting the assembly of micro-assembly system was the assembly unit. obtained the inherentfrequency and vibration types through finite element modal analysis for the assembly unit；In this paper,in order to verify the simulation model is reasonable, the modal experiment was made. The simulationmodel of the assembly unit deviation was proved to be unreasonable by comparing the test results withthe results of finite element analysis.(4) In order to ensure the accuracy of finite element analysis and subsequent other simulations, theoptimization for the simulation model of the assembly unit was studied. Firstly, the ball linear guide railpairs in the assembly unit are found out through the structure analysis. Then, according to the contactform of ball linear guide rail pair, the theoretical contact model based on Hertz contact theory and thefinite element simulation model with the ball linear guide rail pairs were built, and the simulation resultswhich are more.accurate compared to the finite element simulation model without the ball linear guiderail pairs were obtained. Last, taken into the limitations of Hertz contact theory, the method of seekingthe optimal solution of the contact stiffness based on the theoretical contact model and genetic algorithmis proposed, and the optimal solution of the contact stiffness, more accurate finite element simulationmodel and accurate modal parameters were obtained which show the stability of the micro assemblysystem and provide reliable theoretical basis for the follow-up simulations.