Underwater Operation Analysis And Control System Study Of Multifunctional Maintenance Equipment

As an important part of the underwater pipeline maintenance equipment,the submarine pipeline multi-function maintenance equipment can complete multiple maintenance operation on the broken pipeline,such as grinding,cutting and chamfering,etc.Then the leakage of oil will be prevented and the environmental pollution and economic loss will be reduced.Therefore,it's necessary to study the multi-function maintenance equipment.The crawling stability,machining process and underwater control system of multi-function maintenance equipment are studied.The underwater crawling stability of multi-function maintenance equipment is studied.A mechanical model of the equipment during crawling is built in consideration of the gravity,buoyancy and current force,etc.The external forces and torques of the equipment and the friction and friction torque of the clamp during are solved.Then the crawling stability equation of the equipment is obtained.After analyzing the equipment,the crawling stability is found to be orthogonal to diameter of the operated pipe.Then the worst stable condition is calculated and the equipment won't move in axis direction or overturn in circumferential directions.Thus the equipment will remain stable in any case.The system after clamping is simulated by Abaqus to validate the theory analysis and there is no relative displacement between the equipment and the pipe.The cutting edge is discretized and the infinitesimal element is analyzed.The Equivalent cutting plane is obtained by building the space model of the equipment during oblique cutting.The stress distribution of the workpiece and the temperature distribution of the deformation zone is calculated by J-C constitutive equation of the material.The formula of anti-cutting force is obtained by integrating and spatially alternating the stress.The cutting process is simulated by Abaqus and the cutting force is found to be related to the cutting speed within the selected job parameter range.The theoretical model is also validated.Based on the operation requirements of the multi-function maintenance equipment,the working process is analyzed and the underwater control system is studied.The human-machine interface of upper computer is presented based on WinCC and the control program is completed by STEP7.Ethernet communication is used between the upper and lower computer.The S7-200 PLC with multiple development modules is used as the host controller to control the multifunction maintenance equipment and underwater hydraulic source.Two parts of hardware is installed and the software is debugged.The control of cutting force of disk C is realized by controlling its rotational velocity with a speed closed loop control system.A complete experimental study on the multi-function maintenance machine is carried out.The external torque of the equipment during crawling is achieved by rotating cutter disk.The crawling stability is then verified.By comparing different cutting effect,a reasonable range of operating parameters is confirmed.The simulation and theoretical results of cutting force are then verified.The sealing and pressure resistance of the electric control bunker was tested.The electric control warehouse,valve box,deep water hydraulic source and the whole multifunction maintenance machine is tested and the reasonability and stability of control system is verified.