A New Port RTG Spreader Automatic Control System

In recent years,rapid development of science and technology,especially networking,internet plus and so on,brings new opportunities and challenges to traditional industry.To improve the intelligent level of port equipment and production organism,work efficiency,and relief worker shortage and cost raise,it is imperative to build an automated container terminal.In general,container handling operation is finished by rubber tyred gantry crane(RTG)manipulated by man on the old pier.In the traditional RTG lift mechanism,all the ropes are controlled by one frequency transformer,and translation rotation motion is realized by means of cylinder,with accurate observation of the worker,which improves requirement for operators,and reduces control precision.Furthermore,rope length and spool will deform with working long hours,which causes spreader uneven.Therefore,the improvement of RTG automation is necessary for automation and intelligence of the pier.RTG automation system has serveral new requirements.RTG automation transformation includes a number of key technologies,especially lift control of spreader which is the performer of RTG Spreader and container alignment control is also very important.This paper transforms anti sway system,control system hardware structure and software architecture of spreader,designing a new spreader control system.Firstly,this paper does the research on the spreader lift mechanism and anti sway system,analyses the shortage of the previous lift mechanism,and proposes a new eight-rope anti sway system.The system has eight reels and eight servo synchronous motors,increases the flexibility of the spreader,and make possible for translation and rotation.Aiming at leveling,a new leveling method "pursuing high&torque aided leveling" is proposed.Aiming at translation and rotation,location planning is realized by electronic cam,which has precise position control.Secondly,spreader and container alignment is realized by laser sensor.The shelter of laser sensor means the failure of spreader and container alignment,so the spreader will adjusts container until the realization of the alignment.Besides,in electric control,spreader control system is modified,and eight-bearing AC servo control system based on POWRLINK is built,which improve positioning precision and control efficiency.Meanwhile,POWERLINK bus communication improves the synchronization performance of the system,which simplifies the remote spreader wiring.Thirdly,in software architecture,based on B&R controller and automation studio,real-time Ethernet communication is realized,and third party servo control library is developed.In the paper,single-bear and multi-bear coordination control program is compiled and based on modular programming,spreader automatic control function is realized.Spreader automatic control system has three operation modes:automatic mode,remote manual mode and maintenance mode.Finally,with experiment platform,serveral technical indexes of spreader automatic system are tested and validated,including POWERLINK communication test and spreader operation test,and test results are recorded and analyzed.The experiments show that the overall scheme is feasible.Lift control,leveling function and translation rotation function of spreader can be realized which improves the stability and reliability of the system.