Autonomous Operation Control Of Pipeline Climbing Detection Robot

The detection of pipelines in service is vitally important.However,existing manual detection has insufficient including getting low precision,existing blind area,taking long time,much costs,and high risk.Therefore,it is necessary to develop a mobile detection robot substituting for manpower.In this paper,aimmed at the application in the boiler inner pipeline of thermal power plant,a robot system for climbing detection along the pipeline is designed.The autonomous operation control of the robot is studied and implemented,and the detection is carried out by the equipped instruments.The significances are as follows:Manual detection operation is replaced by robots,which can improve efficiency while reducing costs,and has a great engineering significance.The research of robot autonomous operation control of climbing detection robots has referential significance of robot substitution in related fields.The main work completed includes:(1)General scheme of pipeline climbing detection robot.According to the pipeline environment and detection requirements of power plant superheater system,the motion function and detection function for the robot to complete the operation was analyzed.The detection scheme based on the infrared camera was proposed,and the non-destructive testing scheme based on the ultrasonic guided wave theory was proposed.Then the structural scheme of the robot was.determined.(2)Kinematics research.Firstly,the kinematical model of the robot was established based on the modified Denavit-Hartenberg method.The inverse solution of the kinematics equation was obtained,and four typical gaits were designed according to the task requirements.Secondly,interpolation method including the quintic polynomial and cubic polynomial with intermediate path points were used to obtain the motion trajectory of every joint,which could ensure the smooth and reliable movement of the robot.Finally,the source of the error in the movement of the robot was analyzed.An autonomous calibration model was established,and the estimation algorithm of the stiffness and deformation of the structure was proposed.A step-by-step detection and correction method based on multi-sensor fusion was introduced for the autonomous operation control of robt.(3)Autonomous operation control.Firstly,for the control requirements of pipeline climbing detection robots,a hierarchical control strategy was proposed to build a robot control system.Secondly,the servo parameters of the three-loop control of the motor were set.Then,the motion trajectory tracking of the rotary joint was achieved trough PID controller,and the clamping force of the claw was achieved through the PI controller.Thirdly the robot monocular vision system for distance measurement was established.Finally,control system program was designed by using LabVIEW.(4)Experiments of climbing detection robot prototype.Firstly,experiments of visual ranging and ultrasonic ranging accuracy were performed to verify the accuracy of the sensing system.Secondly,the idling and climbing experiments were performed respectively.The PID controller could achieve good tracking result of joint motion trajectory.Finally,the experiments of robot autonomous detection operation were carried out to verify the feasibility of step-by-step detection and correction method.