Design And Error Analysis Of A Precision Assembly System For ICF Parts

The precision assembly system for micro parts is a hot research on the current international, for micro parts are small in geometric dimensions, poor of structural stiffness, easy to broken. Based on the coaxial alignment detection principle proposed by our team, this paper studies a precision micro assembly system, and takes the core part of the Inertial Confinement Fusion(ICF for short) target as the assembly object. To facilitate the highprecision alignment assembly system to do error compensation, hardware selection and precision verification, this paper analyzes the motion error sensitivities on the sensitive directions and estimates the system precision by building error transfer model and measuring the accuracy of stages. The main contents are as follows:(1) The background and significance of this project is introduced, and status of the micro-assembly technology and error analysis methods at home and abroad are elaborated. Moreover, research progress of assembly system for ICF target component internationally is described and analyzed. Thus, the key technologies and error modeling method for microassembly systems faced to microspheres and diagnostic band component is determined.(2) The precision alignment assembly system for microspheres and diagnostic band component is researched. Firstly, the part features of assembly object ——microspheres, diagnostic band and fill tube are introduce, as well as the assembly precision index. Secondly aimed at the structural and dimensional characteristics of objects, micro vacuum grippers for complex three-dimensional micro-devices are designed. Meanwhile, theoretically detailed calculations of the grippers' adsorption reliability are made, to verify the lossless gripping. The coaxial alignment detection principle of the study group is introduced, and the orthogonal biaxial space positioning system program is presented. Lastly, the parts assembly process, alignment detection and control scheme are developed.(3) Error transfer model of a high-precision alignment detector is established. The overall structure and work process of a high-precision alignment detector with multiple degrees of freedom is introduced firstly. For the motion errors of visual system will also affect the assembly accuracy of the system, a comprehensive error transfer modeling method integrated vision system and assembly system is proposed by the theory of multi-body system, and the maximum deviation of the displacement and angle on the assembly object caused by geometric errors are calculated.(4) The assembly accuracy of the high precision alignment detector is analyzed and estimated. The geometric error source of the system is analyzed firstly, then error transfer model of precision motion platforms are built, and the geometric errors are measured by laser interferometer, thus the key orientations for assembly object deviation are identified. Use the Sobol method which was based on variance to do the error sensitivity analysis on four key directions, whose results can guide the hardware selection and installation requirements, also in favor of error compensation for precision motion platforms. Studies have shown that highprecision alignment detector enabling the high accuracy lossless assembly for micro-parts by using submicron-resolution CCD camera alignment system, improving athletic accuracy of the assembly executed axis by the two-dimensional error compensation method combined macro-micro, and taking advantage of the mapping between micro-power and micro-pose monitoring the contact process of assembling parts.In order to optimize the assembly systems for ICF components and improve its assembly accuracy, this paper develops a precision alignment assembly system for micro-target parts; in addition, establishes a "vision system + mechanical system" error propagation model, analyzes and improves the accuracy of the high-precision alignment detector developed by our group later. The contents of this paper provide technical support for precision lossless assembly of ICF components.