| With the improvement of industrial level and living quality,pipeline transportation can be seen everywhere.Domestic sewage,oil,natural gas,tap water and other transportation cannot be separated from pipelines.In the process of using the pipeline,the damage of the pipeline is inevitable,and the damage of the pipeline will bring inestimable waste of resources and even serious harm,therefore,the daily detection and maintenance of the pipeline is also crucial.Although today’s common traditional pipeline robots can replace the manual detection of pipelines,greatly improving the efficiency of work,traditional pipeline robots are mostly rigid robots,which often limit the robot’s access to pipes with complex shapes or small pipe diameters.To compensate for this defect,this paper designed a kind of worm-inspired pneumatic in-pipe robot with fabric skin,studies the operating characteristic of anchor device and main section,studies the influence of some parameters on them,studies the environment adaptability and movement performance of the soft robot,and explores the pipeline detection applications of robot.The specific research contents of this paper are as follows:(1)Taking the worm as the prototype and according to its physiological structure and motion characteristics,a three-stage soft-bodied worm-inspired robot was designed.The two ends were anchors of the Kresling structure,and the middle part was the main section of the accordion-like structure for expansion.Each module is prepared based on a kind of fabric-paper composite material,which is folded into a 3D structure by the characteristic origami process,and assembled in a modular way so that the robot can flexibly adapt to different working environment and work requirements.(2)The test scheme of the output friction of the anchor was designed,and the influence of the inflation time,inflation pressure and the inner diameter of the working pipe on the output friction of the anchor was investigated.The experiment showed that before the anchor was not fully expanded,the longer the inflation time,the greater the friction of the anchor;When the aeration pressure is 20 k Pa,the anchorage device cannot obtain sufficient expansion to obtain sufficient friction.When the aeration pressure is 40k Pa and 60 k Pa,the anchor can fully expand and obtain the same maximum friction.Moreover,the higher the aeration pressure is,the faster the friction will increase,and the faster it will reach the maximum friction.Anchoring can be generated within a certain range of diameter of the pipe,and with the increase of the pipe diameter,the maximum friction of the anchoring device will be reduced until the anchoring is not generated at all due to the absence of contact with the pipe inner wall.(3)The paper designs the test scheme of the elongation and the lifting capacity of the weight of the soft actuator,studies the influence of the inflating time,the inflating pressure,the number of creases and the paper gram weight on the elongation of the main section,and studies the influence law of the number of creases and the inspiratory pressure on the lifting speed of the main section.The research shows that the elongation of the main section increases with the increase of the number of creases and the inflating time.When the number of creases is 6 or 7,the main section with the paper weight of 80g/m~2 has the largest elongation at the initial stage of elongation,while the main section with the paper weight of 120 g/m~2 has the elongation at the end of elongation.When the number of creases is 8,the main section with the paper weight of 120 g/m~2 has the largest elongation.With the increase of the inflation pressure,the elongation of the main section also gradually increased,for the main section which has 6 creases,the paper gram weight has little effect on the elongation;When the crease number is 7,the elongation of the main section with the paper weight of 80 g/m~2 is the largest,followed by 120 g/m~2,100 g/m~2is the smallest,for the main section which has 8 creases,the pressure of 20 k Pa or 40 k Pa is consistent with the crease number of 7,when the air pressure is 60 k Pa,the paper weight of 120 g/m~2 has the maximum elongation.Under certain conditions,the body section can lift 70 times its own weight to the complete contraction of the body section.If the inspiratory pressure is too low or too high,it is not suitable to lift the weight in the main section.Under the appropriate inspiratory pressure,the increase of creases can increase the speed of lifting the weight.(4)The pneumatic channel system and control system of the worm-inspired pneumatic in-pipe soft robot are designed.Test the influence of the aeration time,crease and paper weight per unit area of the main section on the movement speed of robot,when the number of crease is 6 and 7,the robot’s movement speed as the charging time increases,but the increase of the speed is slow,and when the weight per unit area of the paper is 80g/m~2 and 120 g/m~2,the robot moves faster.When the number of creases further increases to 8,the movement speed of the robot increases and then decreases with the increase of aeration time,and the movement speed is faster when the weight per unit area of the paper is 100 g/m~2.In the experiment,the average speed of the robot in horizontal one-way,horizontal two-way and vertical crawling was tested,and all showed good performance.In the experiment,the average speed of the robot in horizontal one-way movement reached up to 3.4 mm/s.The average speed of the robot in horizontal one-way movement was 3.475 mm/s,while the average speed of the robot in vertical crawling was 2.1 mm/s.In addition,although the average speed of bending crawling,underwater movement,obstacle clearing and dragging heavy objects has been reduced,it still has good performance.The robot also has good deformation resistance and impact resistance.(5)The steering module based on shellfish structure was designed to meet the needs of pipeline detection work of the robot,the camera was selected,and the steering module and camera were assembled modularized on the head of the robot,and the pneumatic channel system and control system for pipeline detection of the robot were designed.The testing capability of the robot pipeline is tested experimentally and the defect images obtained from the inner wall of the pipeline are classified. |
