The Study Of Multi-Axes Synchronization Motion Control Technology For Pipeline Welding Machine Over Control Network

Full automatic and continuous multi-layer welding technology is used in welding process, which includes root pass, filler passes and map pass, according to the characteristics of seafloor petroleum pipeline for thick wall. If speed asynchrony happened between walking and swing mechanism, which controlled by pipeline welding machine coordinately to finish welding process of each layer, the quality of surfacing and weld shaping would get worse; on the other hand, there are two schemes of welding that maintain the current while change the speed and another is just the opposite to fulfill the purpose of surfacing symmetrically. The synchronism between two mechanisms is important in either of these schemes.The synchronization motion control technology of walking and swing is studied to achieve the performance requirement. The concurrent, master-slave and cross-coupled method have been used in experiments to compare the synchronization performance of these four methods. It turns out that cross-coupled method has better function. A cross-coupled synchronization controller is designed to compensate the speed of two motion systems based on what have done before; moreover, fuzzy control method is applied to tune PID parameters for better performance. Through the establishment of simulation model of cross-coupled control with fuzzy-PID and ordinary PID and master-slave control proves that the first control method can achieve better synchronicity. In order to assure each sub system work coordinately, control network is used to connect main control system, motion control system and other auxiliary equipment. By gathering the real-time data in welding, walking and swing process can be controlled precisely with servo system according to motion parameters which decided by welding technology.The simulation results shows that the cross-coupled control with fuzzy-PID has smaller dynamic velocity drop and recovery time than other methods. The experiments taken in X-Y platform shows that the mean square deviation of synchronization error under cross-coupled control is54.67pulse/s, which is smaller than other three control methods. It proves that cross-coupled control with fuzzy-PID has better synchronization performance.