Development Of An In-pipe Robot With A Novel Differential Mechanism

At present,the in-pipe robot is one of the most direct and effective way to inspect and clean the industrial pipelines.With the pipeline layout and application environment being more and more complex,the in-pipe robots need higher requirements on structures and functions.Besides solving the parasitic power circulation problem,the in-pipe robots also need higher adaptability,active steering ability and brake ability,which has become an important subject of the in-pipe robot research.In this paper,an in-pipe robot with a novel four-axial differential mechanism is developed,which can be applied to pipelines with complex conditions.The structure and working principle of the four-axial differential mechanism are analyzed.The results show that the mechanism has the characteristics of adaptive differential and equal torque distribution.The pipe diameter adaptive mechanism with a typical ball screw and flexible robs is developed,the mechanical model of which is validated by the numerical solution.An active steering mechanism with two revolute joints is designed.And meanwhile,the power transmission mechanism for transferring power,the brake mechanism for preventing driving wheels from slipping and the elastic support mechanism for front-end support are developed.Finally,the three-dimensional model of the in-pipe robot is established.Based on the structure of the in-pipe robot,the motion trajectory model and velocity model turning in an elbow are established.The locomotion of the in-pipe robot driving through a branch is analyzed,and the planned steering trajectory is given and discussed.In addition,the obstacle crossing model is established.Combined with the influence of self-weight,the tractive force of the in-pipe robot is corrected.The quantitative analysis of the locomotion characteristics above provides a theoretical support for the in-pipe robot designed in this paper.Based on the virtual prototype technology,the validation of the in-pipe robot is demonstrated by the simulation experiments.In the simulation experiment of the robot turning in an elbow,the robot can drive through the elbow smoothly and the simulation velocities of the driving wheels are in accordance with the velocity model.In the branch pipe simulation experiment,the robot can drive straight or turn through the branch successfully.In the traction force simulation experiment,the actual tractive force and the corrected tractive force of the robot are in accordance with the theoretical analysis.The simulations above show that the in-pipe robot meets the design requirements and can drive stably in a variety of complex pipelines.