Research On Multi-mode Emergency Ejection System Of Full-ocean-depth Underwater Vehicles

With the continuous development of society,the number of non-renewable resources on the land has gradually decreased,and the development and utilization of marine resources have attracted people's attention.The development of the ocean requires advanced technology and equipment.The AUV plays an important role in the detection and development of marine resources due to its features such as its no-cable,large operating range,and strong maneuverability.AUV works in a complex marine environment and safety is one of the most important issues in its research and application process,As an AUV emergency self-rescue device and a non-powered heave drive actuator,the emergency ejection system has attracted the attention of researchers and users.For full-ocean-depth AUVs,their carriers and actuators also need to withstand an external seawater pressure of 110 MPa.At the same time,in order to improve the reliability of the emergency ejection system,it is necessary to adopt different driving methods to implement redundant ejection for AUV under different safety conditions.Therefore,the study of full-ocean-depth multi-mode emergency ejection system to ensure the safety of the AUV has important research significance and practical value.In this paper,we focus on the following aspects of the full-ocean-depth multi-mode emergency ejection system and reliability analysis methods:(1)Research the overall scheme of the multi-mode emergency ejection system of full-sea deep AUV.According to the main technical indicators of the emergency ejection system,the functional requirements of the throwing system and the problems that need attention in the design are analyzed.In order to solve the problem that 40 kg ballast is difficult to install,the split ballast structure is studied.In order to determine the driving source and driving method suitable for the full-sea deep AUV multi-mode throwing system,this paper analyzes the typical driving source and driving method.In order to ensure the reliability of multi-mode dumping system,this paper studies the redundant dumping method,analyzes and determines the overall scheme of the combination of active dumping and passive dumping,and designs the workflow of the loading system.(2)The structural design of the multi-mode emergency ejection system.In order to improve the reliability of the throwing system and increase the redundancy of the driving method,this paper designs the hybrid structure of active and passive throwing.In order to solve the problem that the three driving modes form redundant driving and solve the problem that the ballast needs to be released reliably when released,the fixing is not required when releasing,and the ballasting is easy to operate,the throwing release mechanism is designed,and verify the reliability of the release mechanism through experiments.In order to realize the discharge of the electromagnet and the motor with less power,the design of the electromagnet and the motor expansion mechanism.In order to make the electromagnet work normally under the external pressure of 110 MPa,the sealed magnetic conductive structure of the electromagnet is designed,and verify the magnetic permeability and sealing performance of the sealed magnetic conductive structure through experimental verification.(3)Research on the reliability of multi-mode emergency ejection systems.Aiming at the complexity of multi-mode dumping system,it is difficult to directly analyze the reliability problem.The system partitioning of multi-mode dumping system is carried out.The functional block diagram of the multi-mode dumping system,the system hierarchical partitioning diagram,and the functional hierarchy and structure level mapping diagram are established.Aiming at the problems of multi-mode throwing system parts and possible failure of each part,the possible causes of the faults are analyzed,and the detection methods and solutions are proposed to establish the FMEA table.In order to solve the problem of surface crystallization of parts in deep sea environment,this paper analyzes the crystallization process and proposes a solution.In order to solve the problem that the parts may be compressed and deformed in the whole sea depth environment,this paper conducts static analysis on the parts with large deformation,calculates the deformation amount,and proposes a solution.Aiming at the impact of the first ballast on the carrier,the impact reliability of the second electromagnet is affected,and the dynamic analysis of the situation is carried out to verify whether the electromagnet suction meets the requirements.(4)Develop a multi-mode throwing system experimental prototype and conduct experimental research.Developed a multi-model throwing system experimental prototype.In order to verify the magnetic permeability of the electromagnet-sealed magnetically permeable structure developed in this paper,the electromagnet driver of the original magnetically permeable,externally threaded,machined-threaded and externally threaded electromagnet actuators.In order to verify the sealing performance of the electromagnet-sealed magnetic conductive structure developed in this paper in the whole sea depth environment,100 MPa pressure test was carried out through a pressure tank;In order to verify whether the encapsulated electromagnet can be normally discharged under the environment of 100 MPa external pressure,the experimental component with time delay function is designed to conduct the electromagnet on-off function test in 100 MPa environment.In order to verify the reliability of the multi-mode load-distribution system designed in this paper when the AUV is tilted at a certain angle,the on-board dumping experiment when the AUV tilt is 30° is simulated.