Research On Assembly Force And System Performance For Micro Assembly Based On Coaxial Alignment

The high precision micro assembly system is currently a hot research on the international and the key problem is the accuracy alignment method.Based on the coaxial alignment detection principle proposed by our team,our group developed a precision micro assembly system fitted with submicron accuracy.In order to ensure the assembly precision and stability of the system,this paper analyzes the static and dynamic characteristics of the micro assembly system,and provides the basis for subsequent optimization.Aiming at the problems of the existing method,the paper establishes a high-precision alignment method based on the mapping between assembly force and pose and verifies it by FEM and experimental verification.The method is a new ideal for the micro assembly and provides technical support for the automated assembly.The main contents are as follows:(1)The background and significance of the precision micro assembly system is introduced,and research progress of the robotics micro assembly technology component internationally is described.The limit of the conventional optical alignment method and the drawback of existing alignment methods based on the assembly force are summarized.(2)Firstly,this paper analyzes the demand for assembly of middle-scale three-dimensional complex micro systems.Then the structure of the microassembly system and its key technology is introduced.The static characteristics analysis of the system is made by FEM.The whole static characteristic of the system proves that it has good rigidity for overall structure.Moreover the static characteristic of the force detection system is researched by experimental method and proves its reliability.(3)The dynamic analysis of the micro-assembly system is made by experimental modal analysis.Then the finite element model of the gantry is built and make the modal analysis by FEM.We can get more accurate results by comparing the results obtained by the two methods.And the simulation model of the gantry was proved to be reasonable.On the basis of the modal analysis results,we can avoid the low frequency resonance region and ensure the assembly precision and stability of assembly system.(4)Aiming at the problems of the existing method,the paper establishes a high-precision alignment method based on the mapping between assembly force and pose.Firstly,this paper analyzes the relationship between the pose and assembly force during the assembly of the shaft and hole,then establishes the mapping between assembly force and pose.On the basis of the mapping of the assembly force and pose of the shaft and hole,a high-precision alignment method is established.(5)Firstly,the experiment platform is established based on the high precision micro assembly system.Then the stiffness of the micro-holder is measured.After that,we verify the mapping between the assembly force and pose during the hole assembly.Then the assembly accuracy was verified.The result proves that the method precision can reach sub-micron.