| Subsea production system is vulnerable to marine corrosion,fishing net dragging,falling objects and other damages because of its long-term work in the seabed.The research on the underwater long-term video monitoring system is carried out to provide full coverage real-time video monitoring,effectively improving the production stability and economic benefits of the Subsea production system.Aiming at the problems of the underwater video monitoring equipment,such as the short life of biofouling protection,the inability of underwater imaging for long-distance and all-round clear imaging,the structural design of underwater long-term video monitoring system is carried out,the biofouling protection technology and underwater light imaging effect are studied,the control system hardware platform is built,and control program is designed,finally,experiments are carried out to verify the performance of each device.On the basis of defining the performance index of underwater long-term video monitoring system,this paper analyzes its working principle,puts forward the structural design scheme,and analyzes the performance of each part of the system.The structure of pressure resistant shell is designed,the strength,stability and sealing performance of the pressure resistant shell are analyzed,and the finite element analysis software is used to simulate the heat dissipation performance of the equipment in shell;The structure of the underwater motor is designed,the hydrodynamic resistance and pressure compensation volume are calculated;The support and base structure are designed,and the shielding characteristics of the support to the camera and the underwater docking and locking process are analyzed.On the basis of the existing adhesion mechanism of marine fouling organisms and biofouling protection technology,according to the life demand,the biofouling protection scheme is proposed after comparative analysis.Through the research on the sterilization effect of ultraviolet in water,the maximum protection distance is obtained,and the protection life of ultraviolet lamp is calculated.Through the research on the best protection effect of ultraviolet on hemispherical glass,the position relationship between ultraviolet lamp and hemispherical glass is obtained.The biofouling protection device is designed and the protection effect is analyzed.The underwater optical characteristics and underwater optical imaging effect are studied.The mathematical model of the light flux and the lowest camera illumination is established,the ratio of the light flux to the lowest illumination under the maximum monitoring distance is calculated.The mathematical model of the full view imaging light intensity and contrast is established,and the imaging light intensity and contrast with the change of monitoring distance and angle are calculated.According to the requirements of underwater long-term video monitoring system for the position control of motor and brushless servo,the brightness control of lighting lamp and the duty cycle control of ultraviolet lamp,the hardware selection and design of the control system are carried out.The servo-controlled program of brushless motor based on CAN bus communication is designed to realize the constant speed,fixed point and cruise motion functions of horizontal rotation,and the synchronous scanning control program of the brushless servo is designed to realize the scanning video monitoring of underwater objects.The underwater imaging test platform is built to test the underwater imaging effect,getting the imaging effect of different distance and different angle,and verify the imaging performance of the underwater video monitoring system.The motion control experiments of the underwater motor and the brushless servo are carried out to verify the performance of underwater full view motion control.And the performance test of the biofouling protection device is carried out to verify the protection performance of the ultraviolet germicidal lamp. |
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