Precision Analysis And Control Of The Precise Assembly System For Multiply Ring Parts

The assembly precision of the multiply ring parts need to be controlled in microns, and its operating characteristics requires that rings have good consistency with each other. Traditional assembly methods, which are the manual methods, have poor precision and consistency. On the basis of the developed systems, this paper studied the quality factors of assembly and the methods of precision control to improve the assembly quality.Based on the rings and the assembly mold, the system of quality factors has been confirmed and their modes of actions have been analyzed. The paper introduced the structure of the precision assembly system and the assembly requirement after confirming the factors which influence assembly precision and assembly consistency.The errors of assembly module and rotary table module with their impacts on the system have been analyzed. The pose error of the end effecter has been acquitted by error propagation and fitting in theory. The errors of assembly module and turret indexing module in the actual situation have been measured by testing experiments. Based on the formulas derived by theoretical analysis, this paper calculated the actual systematic errors according to the simulation and test results of the experiment.The tolerance of the ring is one of the main factors affected the assembly precision and reliability. The relationships between the interference of rings and its maximum stress as well as reaction force have been acquired by the simulation of rings with different design tolerance. In fact, the reaction of the ring is the system assembly force. Assembly force getting from assembly experiments on two kinds of rings with different tolerance agree with the simulation results of reactive force. Taking assembly forces into account, as well as the supporting force in the contractile epoxy adhesive in the next process after assembled, the tolerance of the rings were selected based on the results of the simulation and assembly experiments.To achieve the precision control of the assembly system, this paper studied the error compensation methods. A force/stiffness compensation method is proposed to compensate the deformation caused by the high assembly force. All the factors that caused errors were considered as an overall error, the error detected by the force sensor and linear encoder. Inductive gage is used to compensate the rotary table platform wobble error. The assembly quality has been improved in the assembly experiment which proves the reliability of the compensation method. In the experiment, the ring spacing errors and ring peipendicularity errors are controlled in20μm.Above all, based on the influencing factors of the assembly quality, this paper completed precision control by error analysis, ring tolerance formulate, system error compensation. The assembly results show the precise assembly system for rings can meet the requirements.