Research On The Key Technology Of The Control System Of Surface Laser Etching Equipment

With the rapid development of various technologies such as national defense security and aviation technology,there is an increasing demand for functional structure processing on the surface of curved parts.For example,perform FSS unit pattern etching on the surface of the radome to achieve the purpose of stealth of the radome.At present,there are few research results on the surface pattern etching of large-scale variable-curvature radomes at home and abroad,and some small-sized rotating body thin covers or curved surfaces.The accuracy of the surface graphics processing of the parts is about 20 μm,which cannot meet the current needs.In order to solve the problem of high-precision laser etching of FSS unit graphics on the surface of the large-scale variable-curvature radome,this thesis constructs a curved laser etching equipment with a double-turntable four-axis structure suitable for the large-scale variable-curvature radome,developing an electric control system for surface laser etching.The development of the electrical control system for surface laser etching includes two aspects: hardware and software.The hardware design includes three subsystems: motion positioning servo system,automatic focusing system and laser galvanometer system.According to different operating positions,the software part can be divided into upper computer software and lower computer software.The upper computer software is responsible for communication control,and the lower computer software mainly carries out the motion positioning servo-control program.In the entire electronic control system,the upper computer software occupies a leading role.The upper computer software includes five modules: position acquisition module,initial position calibration module,curved array module,galvanometer scanning and laser etching module,and data monitoring and display module.After calibrating the initial position of the radome,obtain the processing point information through the array module,generate the motion program,and control the XYAC four-axis movement to the position processed;the upper computer controls the automatic focusing system to complete the focuse,and the laser galvanometer system will be in the upper position the FSS unit graphics transferred from the machine are converted into high-speed scanning and filling motion,and the laser beam is controlled to move along the graphic trajectory to complete the etching of the FSS unit graphics.The main module function algorithms are: 1.The initial position calibration module adopts the image processing method,uses the least square method to fit the image center of the radome workpiece,and obtains the radome vertex coordinates simply and quickly through the coordinate system transformation,which solves the shortcomings of manual measurement..2.The curved surface array module adopts the method of busbar equal arc length layering and circumferential axial equal distance block method to realize the area division and graphic arrangement of the radome surface.This ring-belt processing method eliminates the space trajectory error and splicing error.3.The dual compensation algorithm of pre-compensation and feedback compensation is used in the positioning movement of the radome’s etching points to compensate for the movement error,so as to improve the positioning accuracy of the etching points on the surface of the radome.4.The equal arc length projection algorithm is used to compensate the etching pattern,avoiding the distortion of the pattern during scanning and etching,and improving the accuracy of the pattern etching.Finally,the system in this thesis has performed a single-axis motion positioning test,a generatrix trajectory test,a two-dimensional plane etching test,and a large-size variable-curvature rotating radome(bottom radius is 188.573 mm,height is 700.062 mm,and the generatrix is spherical cap + parabola Form)surface Y-ring unit etching test,the system is running smoothly,the linear positioning accuracy is about 3μm,and the rotation axis positioning accuracy is within 0.005°;the leg length,size,and spacing of the etching pattern are detected by a microscope,and the two-dimensional plane Y The etching accuracy of the ring unit pattern is about 10μm,and the etching accuracy of the Y ring unit pattern on the surface of the radome is about 15μm.The etching size,leg length,and spacing of the FSS transmission unit meet the system requirements.