Digitalization Method Of Microassembly Space For Digital Microassembly Of Trans-scale Microparts

With the rapid developments of national defense industry,aerospace,medicine and biology and other fields,the demand for micro-electro-mechanical systems(MEMSs)becomes more and more compicatied.At present,not only the scales of microparts constituting MEMSs have gradually expanded from the single micron or millimeter scale to simultaneously cover micron,millimeter and even centimeter scales,but also their materials and structures have diversified characteristics.Microassembly technology and systems have become the important ways to realize fabrication of MEMSs with diversified materials and structures but limited by the depth of field,field of view and resolution of microscopic vision system(MVS),the traditional microassembly technology and systems are difficult to meet the requirements of microassembly of transscale microparts,which has become a bottleneck restricting the development of MEMS technology.There are two main challenges for microassembling trans-scale microparts:one is the lack of the information acquisition that can digitally describe the geometric morphologies and spatial states of trans-scale microparts.The second is the lack of the method and principle for estimating the position and orientation of trans-scale microparts.Focusing on the above challenges,in this dissertation,a principle and method of digitalization of microassembly space for digital description of trans-scale morphology is proposed to obtain digital microassembly space that can simultaneously observe and describe the global morphologies,local features and spatial states of trans-scale microparts with high precision.On this basis,a position and orientation estimation method of microparts described by digital microassembly space based on virtual digital microassembled target and a topological configuration,principle and method of digital microassembly for microassembling trans-scale microparts based on digital microassembly space are proposed.A set of experimental setup for digitalizing microassembly space is constructed,and the feasibilities and rationalities of the digitalization method of microassembly space and the digital microassembly method of trans-scale microparts are verified.The main research and innovations in this dissertation are summarized as follows:1.A principle of digitalization of microassembly space for digital description of trans-scale morphology is proposed to transform the microassembly space containing trans-scale microparts into digital microassembly space expressed by 3D point cloud.Utilizing microscopic tomographic slice scan(MTSS)technique,microassembly space is characterized into MTSS image array.Using depth estimation method to obtain depth of all MTSS images,MTSS spaces of MTSS images are reconstructed.Based on these,digital MTSS spaces are obtained by voxel binary assignment,and digital microassembly space is obtained by spatial transformation and splicing of digital MTSS space array.Among them,MTSS for microassembly space are realized by MTSS technique based on MVS of microassembly system.2.The effects of the steps of MTSS,size of region of interest for focus measurement,size of voxel for discretizing 3D space and magnification of MVS on the morphology description ability of digital microassembly space are analyzed.The method of morphology similarity evaluation of microparts described by digital microassembly space is established,the morphology description abilities(morphology similarity,generalization ability and consistency)of digital microassembly space and measurement accuracy of morphology dimentions by digital microassembly space are analyzed,and the experimental verification are carried out.3.The concept of virtual digital microassembly target is proposed,and the position and orientation estimation method of microparts described by digital microassembly space based on virtual digital microassembly target is proposed.The virtual digital conehohlraum target by 3D point clouds of CAD models of hohlraum and cone cavity is constructed,and the accuracy and feasibility of position and orientation estimation of trans-scale micropart based on digital microassembly space are verified.4.A topological configuration of digital microassembly for microassembling transscale microparts based on digital microassembly space as the basic architecture of realizing different principles of digital microassembly is proposed.The concept of digital pre-microassembly is proposed.The digital pre-microassembly of hohlraum versus cone cavity is studied and realized,and the assemblability of hohlraum and cone cavity is analyzed,the constraints of the microassembly experimental setup is evaded and the accuracy of microassembly position and orientation is verified in advance.According to the topological configuration of digital microassembly,the experiment of digital microassembly based on digital microassembly space and estimation of position and orientation based on virtual digital microassembly target is carried out.5.The experimental setup that can realize digitalization of microassembly space and digital microassembly is constructed.A microgripping robot based on a piezoelectricactuated microgripper is proposed and constructed.Utilizing the constructed experimental setup,the feasibility of the digitalization method of microassembly space is verified,and the morphology description ability and morphology measurement accuracy of digital microassembly space are analyzed.The microassembly position and orientation estimation of trans-scale microparts(hohlraum and cone cavity)is realized,and the accuracies of positions and orientations are analyzed.The digital microassembly of transscale microparts hohlraum and cone cavity is realized,and the microassembly accuracy is analyzed.In this dissertation,the researches and results lay a theoretical foundation for observing the global morphologies and local features of trans-scale microparts,obtaining spatial states and positions and orientations of trans-scale microparts and realizing the digital microassembly and virtual microassembly of trans-scale microparts with high precision.