Design Of Mechanical System And Research On Motion Condition Of Wall-adaptive Magnetic Wall-climbing Robot

It is very important for industrial production to detect the wall defect of large metal tank because of its inflammable,explosive and other dangerous properties.The traditional manual detection method is complicated in operation and requires manual erection of scaffolding and other structures,which has low efficiency and potential safety hazard.With the help of wall-climbing robot with detection equipment,the automation and intelligentization of tank surface inspection will become the future development direction.The work done in this paper is as follows:(1)This paper firstly introduces the research process of wall-climbing inspection robot at home and abroad.In view of the fact that the object of this task is the external surface of the tank wall with curvature,a two degree of freedom rotating mechanism is proposed.The mechanical system is designed with the idea of Modular design,the utility model is composed of a two-degree-of-freedom rotation mechanism module,a permanent magnet adsorption device module,a detection device module,a driving transmission device module and an auxiliary device module,the robot can detect at any attitude angle on the wall.(2)The safety and reliability of the adsorption performance of the high-altitude working robot are considered firstly.Firstly,the failure form of wall-climbing robot is determined to be the sliding and overturning along the surface.Through the static analysis of wall-climbing robot,the adsorption force that the wall-climbing robot does not overturning and slide under any posture is determined.Secondly,the obstacle-surmounting model of the robot is studied,and the main parameters which affect the obstacle-surmounting capability are analyzed,which provides a solution for improving the obstacle-surmounting capability.The driving moment of wall-climbing robot is analyzed,and the classification of turning forms is introduced.By calculating steering friction resistance and combining with Newton’s law of dynamics,the expressions of driving torque about attitude angle,body weight and steering radius are obtained.Through the comparison of simulation data of parameter control,the in-situ steering is selected as the steering form to provide data reference for motor type selection.(3)The pose model of a wall-climbing robot attached to the external surface of a cylindrical tank is analyzed.The position of the contact point between the four wheels and the wall surface,the angle of the two-degree-of-freedom rotating mechanism are obtained by setting up the coordinate change relation matrix between each coordinate system and combining the space characteristic constraint equation,and the relationship between wheel-wall clearance and body attitude angle.(4)The advantages and disadvantages of Halbach array and coupled array of adsorption column device are expounded.Considering the characteristics of the working object,contact-coupled array is adopted to select permanent magnet and yoke material according to the performance requirements.The structure of the variable magnetic adsorption device is designed,and the theory of the permanent magnetic adsorption force and the finite element analysis method are discussed,the influence of multi-structure parameters on the adsorption force is simulated and tested by Maxwell simulation software,which makes the magnetic mass ratio of the design index maximum,and determines the minimum size of the magnetic adsorption device under the condition of satisfying the performance requirement.