The Control Technology Of Precision Drilling For Automatic Drilling And Riveting Machine Tool

In the field of aircraft manufacturing,the application of automatic drilling and riveting system(ADRS)is an important way to improve the quality of aircraft assembly.The process of ADRS is divided into two steps: positioning and drilling.Due to the shape error of aircraft components,the deviation between theoretical coordinates and actual coordinates of the hole is large,so it is hard for ADRS to achieve accurate positioning.The material of each layer is different and the thickness error is large,so it is difficult to determine the switching time of changing the process parameters.Against this background,this paper takes the fuselage components as the application object,and makes research on the control technology of precision drilling for ADRS.The specific contents are as follows:(1)The characteristics of fuselage components and the requirements of drilling technical indexes are analyzed.The ADRS is introduced in detail.The positioning control scheme and process control scheme are put forward.(2)The positioning control method of drilling that uses a laser line sensor(LLS)is studied.The kinematics model and parameter identification of a machine tool are carried out based on D-H method.A feature extraction algorithm of reference holes based on RANSAC space circle fitting is proposed.According to two actual reference holes,the positioning of assembly holes to be drilled is controlled.The calibration experiment of LLS carried out,and the result shows that the error is less than 0.1mm.(3)The process control method that uses current feedback of spindle feed motor for drilling on laminated materials is studied.Based on the analysis of the current characteristics,the moving linear regression of the current filtered by Butterworth filter is carried out,and the control method of variable process parameters that used slope comparison is proposed.The interface identification accuracy of the control method is verified.(4)The overall structure and functional modules of the integrated control software are designed.The software can debug the ADRS,run machining instruction,and complete the function of riveting and drilling.The positioning experiment and the contrast experiment of variable parameter drilling are carried out.