A Control System Designed For Robotic Laser Shape Following Cleaning Of Large Curved Workpieces

Laser cleaning is a process in which high energy density focused laser beam is used to irradiate the material surface in a high speed scanning way,which makes the oil,rust,organic adhesion or coating on the surface of the material instantly sublimate,vaporize or burn away from the substrate surface.How to manipulate the laser beam to focus on the surface of large curved surface workpiece and multi-channel overlap scanning to complete the covering laser cleaning task is a technical problem in the current engineering application field.In order to develop a low-cost,real-time shape following laser cleaning control system for large curved surface workpiece,this paper proposes a design scheme that takes the universal,low-cost and strong expansibility embedded control system as the main control core,and cooperatively controls the six axis robot and the laser cleaning machining head,so as to realize the shape following focusing and block scanning cleaning of large curved surface workpiece.Firstly,the principle of laser cleaning control system and the research and development status of related technologies at home and abroad are analyzed.A universal six axis robot laser cleaning system architecture is designed.The laser cleaning head is installed at the end of the sixth axis of the robot.Then,by analyzing the laser cleaning requirements of large curved surface workpiece,the working principle of laser shape following cleaning for large curved surface workpiece robot is proposed.The control system design scheme which the integrated control board card with STM32 as the main control chip and the upper computer software are designed.The g-like processing code sent by the upper computer software to the integrated control board is used to control the robot and the machining head to complete the surface focusing and block scanning cleaning.According to the system scheme,the hardware circuit and host computer software of the robot laser cleaning control system are designed in detail.In the design of this system,the integrated control board and the upper computer transmit the processing code mainly through Ethernet.The lower computer stores the received processing code in the external SRAM,and uses UDP access lock and code resolution lock to carry out segmented processing code reading and writing control.Every time the processing code is read,an operation is performed.Using the design idea of the number of galvanometer data to complete the length of array,the segmented algorithm of scanning line segments can be realized.The algorithm can scan line segments of any length and speed defined by g-like code.The g-like processing code and the laser rangefinder are used to jointly control the laser cleaning processing head to obtain the coordinate system of the workpiece in the block region,and the robot’s built-in commands such as BASE,ALIGN and DRAW are used to realize the focus of the surface of the laser cleaning processing head with shape and the scanning cleaning of the block.Finally,the robot laser shape following cleaning control system developed in this paper was integrated and tested on a six-axis robot laser cleaning prototype set up independently in the laboratory,and the laser cleaning process test of large curved surface workpiece showed that the large curved surface based on the piecing was complete,the overall cleaning effect was good,and the cleaning efficiency was up to 0.596m2/h.The robot laser random cleaning control system developed in this paper provides a feasible technical solution for the application of laser cleaning of large curved workpiece such as aircraft paint removal,ship rust removal and mold oil removal,and helps to promote the development of laser cleaning technology from hand-held manual cleaning to industrial robot intelligent control cleaning.