Research On Robot Laser Cutting System Based On RW8800 Controller

With the popularity of laser cutting technology,laser cutting is gradually being used in various industries,and the use of robots for laser cutting and the development of special cutting robot control systems have become research hotspots.Most of the3 D laser cutting robots currently available on the market have been modified from the arc welding version and lack a specific control interface for the laser cutting process parameters,which prevents precise control of the laser cutting process parameters.Moreover,most existing laser cutting robots use external height adjusters,resulting in poor following effects,which also affect the cutting effect to a certain extent.The project is based on the RW8800 control system to design a robotic laser cutting system for cutting 1.5 mm sheet metal parts commonly used in automobiles,which can further improve the cutting effect and processing accuracy of 3D laser cutting.The main research elements are as follows.(1)Based on the RW8800 six-axis robot control system,the thesis designed a PWM control signal conversion circuit based on the control requirements of the fibre laser,which has the function of changing the analogue input to adjust the laser power,and ultimately realised real-time adjustment of the laser power on the robot system.In building the following system,the capacitance sensing detection circuit was designed to collect the distance between the cutting head and the workpiece surface in real time using the theoretical relationship between the capacitance change value and the capacitance pole plate spacing.The collection frequency of the circuit can reach up to 500 k Hz,which meets the requirement of collecting distance information in real time.(2)In order to adjust the following height and following speed in the following system in real time,the flexible and versatile characteristics of PLC were used to develop the corresponding PLC height adjustment control program,and the PID algorithm was adjusted to make the following system smoother in the following process.The PID adjustment is stable and responsive,and can guarantee 0.1mm following accuracy in real time when the following distance is 0.1mm～2mm.Due to the large amount of capacitance change data collected,the capacitance cycle ranging program was designed to ensure the accuracy of the collected capacitance change values.(3)As the RW8800 system interface lacks a control interface for the laser process parameters,a special interface for laser cutting was designed using QUI designer software in order to adjust and view the laser power,light output delay and process parameters.In order to monitor the following status in real time,a height adjustment interface was built on the host computer using the MFC framework to reflect the following height and following speed of the following system.(4)Capacitance calibration experiments were carried out to generate discrete point plots using capacitance amplifiers on 1.5mm carbon steel plate calibration data,and then the discrete points were fitted by polynomial least squares and Gaussian function segments.The height following error was measured by inserting and extracting metal sheets of the same material.10 experiments were carried out to measure the height before and after the change by inserting or extracting metal sheets of different thicknesses.The laser cutting process experiments were carried out for the three key factors of cutting power,auxiliary gas pressure and cutting speed,and the effect of single factors on the cutting quality is analysed.The developed laser cutting system has been put into mass production with good results.