Research On Key Technologies Of Macro Micro Combined Micro Assembly Robot System

In recent years,complex microdevices have become more and more widely required in the fields of national defense industry and civil high-tech products.It is of great significance to develop an automated microassembly robot system with high precision,high flexibility and high efficiency to promote the further development of complex microdevices.A macro-micro combined micro-assembly robot system was designed and built,and research work was carried out on its related key technologies.The main work of the thesis is summarized as follows:A system scheme of macro-micro-integrated micro-assembly robot composed of serial industrial robots and high-precision micro-robots was proposed.The serial industrial robot was used as a macro robot to realize the large-stroke flexible movement of the micro-assembly robot system,and piezoelectric ceramic-driven micropositioning stage was designed as a micro-robot to realize high-precision alignment of parts to be assembled.The working space of serial industrial robot was simulated and analyzed by Monte Carlo method.Considering the requirement of high absolute positioning accuracy of serial industrial robots in the assembly space in the micro-assembly process,the kinematic parameter calibration method of the local space(assembly space)of serial industrial robots was studied.The kinematic error model of the serial industrial robot was established,and the influence of redundant error parameters on the identification of kinematic error parameters was analyzed,and the redundant error parameters of the position error identification were removed.The calculation method of identifying kinematic error parameters was improved by using correlation tolerance and matrix singular value decomposition.Based on identifying the size of the Jacobian matrix condition number and the position of the assembly space,the rotation angles of each joint during the local space calibration were determined.Through the local space calibration,the absolute positioning accuracy of the serial industrial robot in the assembly space is improved from 1.704 mm(before calibration)to 0.1362 mm.In order to improve the accuracy and speed of error compensation of the piezoelectric ceramic-driven micro-robot,a novel feedforward/feedback composite control method was proposed.An improved inverse P-I hysteresis model of a piezoelectric ceramic driver was adopted for the feedforward control,and an adaptive control algorithm was adopted for the feedback control,which introduced error-related genetic factors to adjust the weight of old data and new data in real time.The response speed and control accuracy experiments of the micro-positioning stage were carried out.The results show that when the command signal is a square wave signal,the stability time of the system is 53 ms;When the command signal is a sinusoidal with a frequency of 20 Hz,the maximum tracking error of the system is 1.633 μm.A system prototype of the macro-micro combined micro-assembly robot was built.Under the guidance of the micro-vision system,the alignment of the parts to be assembled was realized,and the assembly of the hole-shaft parts with a minimum gap of 10 μm was completed.