Offshore pipeline laying welding robot based on network and field bus techniques

The multiple field bus integration in offshore pipeline laying welding robot system was studied under the guidance of open type control network architecture.A new synergic control system architecture that integrates all function units of welding robot such as network communication of digital welding power source,distributed motion control,angle sensor and other auxiliary systems was proposed,and the welding process database used for history record and process management was established as well.To meet the demand of synchronization of dual motor driving the running mechanism,a novel protocol model named "communication by time-sharing and executing on synchronization" is adopted for simultaneous executing velocity command.The master-slave speed follower arithmetic of dual-motor driven welding robot is proposed under the various loads.Through automation device specification communication technology,a cooperative control strategy is used for managing the welding activities of each welding head to obtain proper overlaying welded joint.With the welding procedure developed in the welding laboratory,a series of sound welds have been obtained efficiently in offshore pipeline laying welding site at Bohai Sea.The welding experiments results show the rationality and effectiveness of the robot and its control strategy.