Study On Dynamics Characteristics Of The Compound Driving Articulated In-pipe Robot

In modern practical engineering applications,pipeline has been widely used in industrial production as an efficient transportation tool.As a special robot,In-pipe robots are used to perform different kinds of pipe work instead of human,increasing attention has been paid to it.As time goes by,there exist series problems: the increasing complexity of the pipeline environment,the longer length of the pipeline and the more and more difficult operation in the pipe,which make human’s demand for the in-pipe robot higher and higher.So far,the characteristics of high endurance,multifunctional and excellent stability of motion have gradually become the standard for evaluating in-pipe robot.The concept of compound driving Articulated in-pipe robot is proposed based on above.Its compound driving meets the requirements of high endurance,and the multi-unit structure satisfies the diversity of robot functions,which lay a theoretical foundation for the development of the in-pipe robot prototype.Based on the concept of compound driving Articulated in-pipe robot.First of all,a general physical model is established.Then,as the research object,static analysis are performed on this model,including the driving force of motor under different attitude angles,the model of fluid driving force acting on the cups and the calculation model of the resistance in the pipe.Finally,the static equilibrium condition is derived when moving in horizontal and vertical directions.The processes how a Articulated in-pipe robot move through a variety of pipe obstacles are described,including weld obstacles and elbow barriers.The comparison between single unit and multi unit for the process when moving through pipe elbow are given,and geometric constraint in the process of passing through a bend is deduced.The influence of differential characteristics of each wheel under different conditions on the steering process of robot is discussed in this paper,and apply the differential characteristics into the process of passing through T type pipe.Based on Virtual Prototyping Technology,the process of passing through a bend and passing through obstacles are simulated.A comparison about the velocity and the angular velocity of the rolling wheel is carried out i n the simulation of passing through elbow pipe,It’s found that,the processes of single unit and double unit walking through a bend are identical.In addition,through simulation,the maximum rotation angle value of the double Hooke’s joints.The main factors that affect the movement of the robotic odometer wheels system through the weld seam are studied by simulation,and the results shows that bouncing height of odometer wheel and the change trend of wheel velocity vary different when the initial velocit y changes.The mathematical model of flow field is established by using CFD method,Under the condition of changing the annular gap size between cups and the inner pipe wall,the flow velocity vector and pressure variation around in-pipe robot are obtained in this paper.The motion process along with fluid flow of PIG type pipe robot is simulated by Fluent,the variation trend of velocity and acceleration under the influence of fluid is obtained.Finally,under the coupling of motor driving force and fluid driving force,the necessity and rationality of compound driving is verified by the motion process of robot under four different working conditions.