Research On Key Technology Of Serpentine Arm Scanning For Acoustic Leak Detection Of Gas Pipeline

Pipeline is an important means of gas transportation,such as natural gas,chemical raw material gas and high pressure steam,widely used in people’s livelihood,service and other fields.As the most common fault of gas transportation pipeline,leakage often brings energy loss that cannot be ignored,serious economic loss and potential personal safety risk.Therefore,there is always a strong demand for pipeline leakage fault detection.At present,although many methods have been developed,the complex distribution of pipelines makes it difficult for fixed monitoring methods to achieve full coverage of pipelines.Because of the advantages of non-contact,strong characteristic correlation and wide application of pipeline acoustic leak detection method,it has become one of the research hotspots in this field to develop a pipeline leak detection technology combining acoustics and inspection.However,pipelines are often laid in a restricted space and are often shielded by other pipelines or structures.It is difficult for acoustic detection sensors to directly enter the area of interest to realize arrival perception,which greatly affects the acoustic detection function.Therefore,the key technology research of serpentine mechanical arm scanning for acoustic leak detection of gas pipeline is proposed.After understanding the relevant technical background,the research scheme of this paper is determined.The research focuses on the design of the rope driven redundant serpentine manipulator,the kinematics and dynamics modeling of the serpentine manipulator,and the control technology of the end-follow sweep motion of the serpentine manipulator in confined space,and the system development and integration are completed.At the same time,relevant experimental studies are conducted to verify the proposed technique.The main research contents of this paper are as follows:In chapter 1,the importance of gas pipeline facilities and inspection technology research is discussed,the basic situation of robot acoustic leak detection technology for gas pipeline are systematically summarized,the existing problems of robot acoustic leak detection for gas pipeline inspection and sweep are analyzed,and the research content and framework of this paper are clarified.In chapter 2,the principle of aerodynamic noise is analyzed,and the principle and influencing factors of gas pipeline leakage detection based on acoustic perception are clarified,providing theoretical basis for subsequent research.On the basis of clear system related objectives,the overall scheme of the acoustic leak detection robot inspection system for gas pipeline based on the snake mechanical arm scanning is designed,and the main key technologies that need to be solved are summarized.In chapter 3,the design and kinematics and dynamics modeling of the redundant serpentine manipulator are carried out.Based on the design of orthogonal hinged serpentine arm and coiled rope drive array,a serpentine arm with redundant degrees of freedom was developed by using rope pull drive mode,and its components were analyzed.At the same time,through the snakelike manipulator kinematics modeling,clear mechanical arm joint space and position space and rope length and joint angle mapping relation,and then using Jacobi differential numerical iterative method to realize the snake-like manipulator inverse kinematics modeling,and based on the Lagrange method to build the dynamic model of snake-like robot arm.The work in this chapter lays the technical foundation for the mechanism and motion control of serpentine manipulator.In chapter 4,the research on the motion control technology of the end follow sweep of the serpentine manipulator in confined space is carried out.In this paper,the safety control margin of the driving rope and its terminal workspace were numerically analyzed for the serpentine manipulator in confined space.Based on the heuristic iterative strategy,an improved inverse kinematics algorithm for terminal following motion control was developed.At the same time,the visual detection and recognition of the area of interest of the pipeline to be inspected was completed,and the spatial coordinates of the scanning target were obtained.Combined with the improved inverse kinematics algorithm above,the control parameters of the scanning motion of the serpentine manipulator were quantitatively determined,and then the scanning motion control of the serpentine manipulator in the restricted space was realized based on visual servo.In chapter 5,on the basis of the research work in the above chapters,the processing and manufacturing of the serpentine manipulator and the development of related hardware and software are completed,and a set of acoustic leak detection robot inspection system for gas pipeline based on the serpentine mechanical arm scanning was developed by combining the serpentine mechanical arm with mobile robot and acoustic leak detection equipment.At the same time,the effectiveness of the platform and technology developed in this paper is verified.In chapter 6,the research content of this paper is summarized and prospected.