Design And Characteristics Of Stepping Walking And Adaptive Mechanism Of In-pipe Robot

The gas and drainage pipeline in municipal engineering will be damaged,deformed or even broken after long-term use.In order to ensure the safety of pipeline,the research of in-pipe robot is gradually rising.Among them,the stepping peristaltic in-pipe robot has excellent decoupling,locking and adaptability,and can realize decoupling of support force and forward resistance when dragging the detection device.However,the multi drive decentralized layout of the stepping robot greatly increases the difficulty of control and maintenance,so it is urgent to carry out the design and characteristics research of walking mechanism and adaptive mechanism of the stepping robot driven by intensive driving.How to reduce the number of driving,reduce the complexity of control and improve the stability of the robot has become a key problem to be solved.Therefore,this dissertation uses the method of mechanism design,theoretical analysis,simulation and experimental verification,and takes "intensive driving,precise coordination,two-way stepping,stable support" as the design goal,systematically and deeply studies the key issues such as walking mechanism of in-pipe robot,theoretical modeling of constant-force adaptive mechanism design,etc.The main contents and contributions of this dissertation are summarized as follows:All kinds of peristaltic in-pipe robots are summarized,and a classification method based on driving number is proposed.Based on TRIZ theory and mechanism innovation method,a single driving two-way stepping robot is proposed to avoid multi driving decentralized layout and collaborative control.The single input and multi output transmission mechanism is designed to realize the precise coordination and synchronization of each body action and avoid the relative leading or lagging action.In order to avoid the limitation of the combination design of the spring and the lower pair mechanism,the transition from the lower pair to the higher pair is made.The passive cam and the tension spring are combined,and two kinds of constant-force adaptive schemes,Passive Sliding Cam(PSC)and Passive Rotating Cam(PRC),are proposed to meet the special conditions of stable support under the variable diameter constraint.The structural parameters of the single drive two-way stepping in-pipe robot are designed in detail,the conceptual design is specified,and a series of guidelines are put forward.Based on the mechanism variation and mechanism inversion innovation method,according to the variation of the stepping mechanism and the time sequence relationship of the axial movement,two kinds of stepping robots,the cam-linkage CLR and the multi cam combined CCR are proposed,and their structural parameters are designed and analyzed respectively to obtain the walking rules of the robot.The analysis shows that CLR can realize discontinuous strong constraint walking under incomplete variation and CCR can realize full continuous strong constraint walking under complete variation.Due to the higher pair characteristics of cam mechanism and complete variation motion of CCR,the design flexibility and positioning accuracy of CCR axial motion law are better than CLR.Based on the characteristics of pipe constraints,the constraint equations of external parameters of the robot are derived,and the n-order symmetric convex set cylinder envelope model is proposed to avoid the interference in the pipe and effectively improve the space utilization and equipment volume ratio in the pipe.The geometrical configuration and constitutive relation of the passive constantforce adaptive mechanism in the pipe are studied systematically.Under the guidance of realizing stable adaptive support and reducing drive under the variable diameter constraint,the PSC passive constant-force adaptive mechanism with tension constraint,which does not depend on the sensor and controller,is proposed to solve the existing problems of active support mechanism,such as large energy consumption,complex control and multi line dynamic disturbance constraint.PSC constant-force adaptive theory based on contour control method is put forward.The analytical solution of PSC theoretical contour is derived and obtained.The important rule that PSC contour satisfies elliptic constitutive equation is revealed.Complex programming and numerical calculation are avoided.A new method and mechanism are provided for realizing constant-force adaption under analytical calculation.In order to realize the stable support under the compact layout,a PRC passive constant-force adaptive mechanism with tension constraint is proposed,which can effectively avoid the selflocking when the passive cam slides;the constraint differential equation of the physical system of the oscillating cam and the tension spring is established,and the numerical solution of the PRC profile is obtained based on the Runge Kutta numerical algorithm,which provides a new method and theory for the design of the compact constant-force adaptive mechanism.The mechanical characteristics of walking mechanism and the output performance of adaptive mechanism are analyzed in depth.Based on the kinematic analysis,the static and dynamic mechanical characteristics of the robot are studied,and the mechanical relationship and characteristic curve of the robot's input and output are obtained.The concept of tractive energy efficiency ratio of in-pipe robot is proposed for the first time,and the analysis of tractive energy efficiency ratio of CCR is carried out.The results show that the energy efficiency ratio of single-drive CCR is more than twice as high as that of isomorphic three-drive robot.The dynamic characteristics of CCR robot are simulated to obtain the critical maximum cam speed to avoid locking failure in the pipe.Based on the proposed design theory of PSC and PRC constant-force adaptive mechanism,the modeling and output characteristic simulation of constantforce adaptive mechanism are carried out,and the critical maximum friction coefficient corresponding to the target output accuracy is obtained.The output force of PRC mechanism is less affected by friction and has better robustness to friction.Therefore,PRC mechanism is selected as the best configuration.Based on OMRON PLC,MCGS touch screen,wireless remote control and drive module,a human-computer interaction control and test system was built.The experiment shows that the forward and reverse rotation of single motor can realize the two-way walking of robot,and the single motor driving mode can greatly reduce the number of streamers.The robot can be used in circular and rectangular cross-section walking environment at the same time,which provides reference for different crosssection pipe applications and walking control simplification.Under the guidance of the proposed design method and theoretical analysis of PRC adaptive mechanism,a prototype of PRC adaptive mechanism is developed.The test shows that when the pipe diameter changes,the change trend of output force is horizontally distributed as a whole,which is consistent with the change trend of simulation output force.The correctness and practical effectiveness of the theoretical method are verified,providing theoretical basis for engineering design and application.This dissertation has 123 figures,27 tables and 155 references.