| A series of comprehensive performance have to be tested in the process of riser development and finished product manufacturing,but there is no relevant research foundation in China and many key test technologies are needed to be studied,which seriously restricts the localization process of the riser.In these technical gaps,the development of pressure testing equipment used to test the whole pressure bearing capacity and sealing performance of riser is one of the important research works.In order to meet the test requirements of riser development and the quality inspection of the products in the future,it is necessary to carry out technology research on the pressure testing equipment of the pressure testing and plugging device of the riser.However,a single standard riser is slender and bulky(length 28 m,weight 16 tons),a dominating tube and five secondary tubes should be sealed in one effort and be tested at the same time,and the test pressure level for each tube is different,the maximum pressure reaches 105 MPa.Simultaneously,the quality of the mechanical activity component is greater than 3000 kg and its blocking outer diameter is as large as 1100mm,accompanying with high precision requirement.In addition,many other technical characteristics,such as large inertia,large size,high precision and 6-DOF system,have brought great technical challenges to the parallelism measurement,angle measurement and other alighment detection and control.In view of this,according to the technical requirements of the riser pressure testing device,the key technologies such as mechanism design,alignment detection and alignment control are studied,and the simulation and physical test are also carried out to verify these techniques.The works in this paper will provide a strong key technical support for the self development of the riser pressure testing equipment.This paper is based on the subsidiary subject "Deepwater drilling riser manufacturing and test specification method study" of the National "863" Plan project "Research on Deepwater drilling riser system"(2008AA09A106).According to the technical requirements of research and manufacturing of riser,overall pressure capacity and sealing performance detection of product,the key technology research and system development of pressure testing device for riser are carried out,which complements the domestic technical gaps.The main research and innovation achievements in this paper are listed as following:(1)A full-automatic riser test pressure sealing device has been developed,which mainly includes a 6-DOF system based on independent motor drive,a detection system based on binocular vision and template matching algorithm,a control system based on the method of the fuzzy PID control.For this system,the assembly alignment accuracy is enough to satisfy the needs of the process,and the automatic precise alignment sealing of the riser flange and the blind plate can be completed within 8 min,which greatly reduces the labor intensity,significantly improves the pressure testing efficiency.In addition,the detection and control troubles of the test pressure device due to big inertia,large size,and multiple DOFs have been solved.(2)According to the structural characteristics of riser and the demand of the pressure testing technology,a 6-DOF mechanism based on the independent motor is proposed.The device mainly includes a pitching mechanism,an axial rotation mechanism,etc.This divice satisfies the requirement of full freedom of space rigid body movement,meets the need of the whole space adjustment and the structural control of the water injection side and blind plate,,provides the structural support for the high precision,efficient automatic alignment detection and alignment control method.(3)According to the spatial posture characteristics of the riser flange,the pattern characteristics of the flange of the crankshaft and the environment background,based on the principle of binocular three-dimensional detection,the automatic detection method of the parallelism of the riser is proposed,and the camera calibration and circular and plane alignment are established.The model is designed to realize the parallel attitude parameters of the space end face of the feature point of the riser flange and the inclination deviation parameter between the flange of riser and the seal face.The method is not only efficient and adaptable,but also has a detection accuracy of 0.1°,it can completely meet the requirements of the accuracy of the detection.(4)For the complex structure of flange end fittings of the riser,changeable environment and other problems,a two-dimensional detection method of spatial pose based on template matching algorithm is proposed.A comparative experimental study by using four template matching algorithms is carried out and the feature matching based on Harris operator algorithm is selected as the pose alignment detection algorithm of the riser.The algorithm has strong anti-interference ability and has a precision of 0.1mm.On this basis,the digital inclination testing technology is introduced.Combined with the parallelism detection method,a detection strategy of the alignment of spatial posture in three-dimensional and two-dimensional direction for rigid body is formed.A high precision alignment detection in the whole process is achieved and the 6-DOF alignment detection problem of the riser end face is solved very well,under the influence of multiple factors(5)Aiming at the problem of the control of large inertia,large size,high precision and 6-DOF system,the fuzzy control technology is adopted in this paper.The spatial 6-DOF relative pose kinematics model based on the inertial coordinate system and fixed coordinate system of plugging device is established.According to the mechanism characteristics of the pressure testing and plugging device,an alignment control strategy based on fuzzy PID is proposed.By using the fuzzy decoupling algorithm and choosing the membership function of the fuzzy decoupling algorithm and the fuzzification and fuzzification rules,the coupling characteristics between the axes are eliminated,the control precision is improved,and the design of the controller is simplified.Experiments results show that this method can reduce the control error to the range of accuracy requirements.The angle error adjustment time is less than 1.5s and the parallelism error adjustment time is less than 2.5s,which shows the characteristics of fast response and high stability.(6)On the basis of the above research,the mechanical structure manufacturing,electrical system construction,software development of the control system,system assembly and debugging,and the optimization and rectification of pressure testing and plugging device for the riser are carried out.And the unit performance test and the whole machine debugging test were carried out in the field,which verifies the validity and practicability of the methods and techniques proposed in this paper.The research work carried out in this paper provides the key technical support for the nationalization of the pressure testing device for the riser,and achieves the full-size pressure test and performance evaluation test of the riser,which fills up the domestic technical gaps.Consequently,the research work of this paper will play an active role in promoting the nationalization of the marine drilling riser,which has substantial theoretical significance and practical application value. |
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