| In offshore oil and gas exploration and development,the subsea production system is the mainstream mode of deep-sea oil and gas resources development.As the brain of the subsea production system,subsea control module(SCM)is responsible for controlling and monitoring the subsea production system,which is one of the important equipment to ensure the safe,stable and reliable exploitation of the subsea oil and gas resources.At present,the core technology of the SCM has been monopolized by developed countries in Europe and America for a long time,the research on the SCM in China is still in the early stage,and the construction of the subsea production system still depends on foreign products.The development of the offshore oil and gas resources in China is gradually moving from shallow water to deep water.Mastering the key technology of the control module of the subsea production system,breaking the foreign technology monopoly,and realizing the localization of the SCM are of great the theoretical significance and practical application value for the independent exploitation of the deep-sea oil and gas resources in China.In this paper,the functional requirements of the subsea Xmas tree are studied and an overall scheme of multiplexed electro-hydraulic SCM is proposed.The configuration of the SCM docking-positioning and locking mechanism is studied,and a SCM docking-positioning and locking mechanism for the multi-loop synchronous docking is presented.The mechanism integrates the docking-positioning mechanism into the locking mechanism with higher positioning accuracy and better centring.The redundant design method and valve block structure of the SCM hydraulic system are studied,and design schemes of the SCM hydraulic system with redundant function and integrated valve block are presented.The reliability of the hydraulic system is improved within the limited space of the SCM.The redundant design method of the electrical control system of the SCM is studied.A kind of the parallel cross redundancy control method is presented,and the performance utilization of the components and reliability of the SCM is improved.A double 2-out-of-2 redundancy system is introduced into the electrical control system of the SCM,the system has high reliability and safety with the fault detection and comparison mechanism.The docking deviation of the proposed docking-positioning mechanism of the SCM is studied.The mathematical model that is used to analyze the maximum allowable docking deviation,positioning accuracy and maximum docking deviation of the docking-positioning mechanism is established,and the sequential quadratic programming algorithm is used to simulate the model.The effects of various parameters on the positioning performance of two positioning modes of the SCM docking-positioning mechanism are analyzed,and the optimal positioning mode of the SCM and the optimal parameters of the positioning mode are obtained.The numerical solutions of the upper limit of the allowable fit gap between the positioning shaft and the positioning sleeve as well as the positioning slot and the positioning key are calculated,and the precision control problem of multiple hydraulic connectors for automatic synchronous precise docking is solved.The maximum allowable alignment and rotation deviation of the docking-positioning mechanism of the SCM are calculated,which provides a theoretical basis for the positioning accuracy design of the guiding mechanism.Regarding the “one side two pins” positioning mechanism as a comparative object,the positioning accuracy of this mechanism and the proposed docking-positioning mechanism of the SCM is analyzed and compared.Aiming at the design scheme of the hydraulic system of the SCM,the reliability and safety of the hydraulic system of the SCM are studied.Based on the failure modes of the hydraulic components,the fault tree models of the safe failure and dangerous failure of the system are established,and the effect of each failure mode on the system reliability and safety is studied qualitatively.Aiming at the Bayesian network combination explosion problem that caused by a large number of components and excessive failure modes of the hydraulic system of the SCM,the dimension reduction method of the Bayesian network model is studied.The two methods,node merging and state merging,for reducing model dimensions are proposed,and the Bayesian network models of the system reliability and safety are established using these methods.The reliability and safety of the system,as well as effects of the various failure modes on the system reliability and safety are obtained.Aiming at the problem that the logical relationship of the parallel cross redundancy control system of the SCM is complex and it is difficult to establish reliability model directly,the decomposition and dimension reduction methods of the system are studied.Based on the reliability block diagram analysis method and the logical relationship of the system,the parallel cross redundancy control system of the SCM is decomposed,and the system dimension is reduced.The reliability model of the parallel cross redundancy control system is established,and the model is solved by Markov method.The system reliability and mean time to failure(MTTF)are obtained.Aiming at the double 2-out-of-2 redundancy system of the SCM,the reliability and safety models of the system under the effects of the multi-parameters are established by combining the Markov model and multiple Beta factor model,and the reliability and safety of the SCM are obtained.Aiming at the time-domain sensitivity analysis method in reliability and safety model,the Morris screening method is extended to the time domain,and the sensitivity calculation methods for the effects of various parameters on the system at any time interval and time point are studied.The effects and sensitivities of various parameters on the reliability and safety of the SCM are obtained.A SCM experimental prototype and a guidance mechanism are developed,and a test system of the SCM is constructed.The test methods of the various functions of the dockingpositioning and locking mechanism,hydraulic system and electrical control system are studied,and related tests are carried out for verifying the docking-positioning and locking functions of the SCM,the hydraulic driven function,redundancy function and emergency safety shutdown function of the hydraulic system,as well as parallel and cross redundant functions of the parallel cross redundancy control system.Aiming at the problem that the positioning accuracy of the docking-positioning mechanism is too high to be measured directly,an experimental prototype of the docking-positioning mechanism is developed.The test method of the mathematical model of the docking-positiong mechanism of the SCM is studied,and relevant tests are carried out for verifying the correctness of the mathematical model of the docking-positoning mechanism. |
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