Research On Emergency Control Technique For Large-scale Unmanned Submarine

With the rapid development of autonomous underwater vehicles(AUVs),the duration of navigation has become longer and longer,the task requirements become more complicated,and the risk increases.In order to guarantee that the self-propelled model can complete complex navigation tasks efficiently and reliably,how to improve the motion stability and survival rate of the self-propelled model when some dangerous factors emerge becomes a hot research topic.Efficient fault diagnosis and decision-making,and reliable emergency action can greatly improve the survival rate and enhance the value of re-planning navigation mission during dangerous situation.This paper focuses on research and test of emergency control technique of large-scale unmanned submarine.Large-scale unmanned submarine has larger size than AUV and is closer to the size of submarine.Compared to large AUV,large-scale unmanned submarine has larger inertia and higher speed;therefore,there will be time delays for changes in navigational status and higher requirement for control technique.Compared to submarine,full-autonomous mode brings more special challenges,such as real-time requirement,efficient decision-making requirement under high pressure and so on.Therefore,this paper designs an intelligent and efficient emergency control method.First of all,this paper analyzes the navigation characteristics of unmanned submarine,estimates navigation risk,and comes up with the corresponding ways to solve those challenges brought by navigation risk.Based on analysis,this paper designs a distributed real-time monitoring frame which has reliable monitoring ability,especially for large-scale systems.In terms of diagnosis and reasoning,this paper models and analyzes the whole faults of on-board systems based on fault tree analysis technique and creates a weighted fault tree matching inference mechanism which benefits quick classifying for abundant of faults.At the respect of decision-making mechanism,this paper designs an expert system combined with finite state machines,which improves its ability to handle large,continuously changing input events in real time.In terms of actions,this paper adopts operating cross rudders,high-pressure air blowing,load-rejection as emergency actions which complete reliable self-rescue floating of underwater unmanned submarine.Finally,this paper builds the model of emergency unit and make the simulation,which verify the single fault diagnosis function,fault fusion diagnosis function,emergency priority setting function and emergency upgrade function of the control technique.