| Underwater wall-climbing robot is a special robot for cleaning the seawater corrosionand marine organisms on underwater wall. When working wall is steel, magnetic adsorption isused on the robot. Increasing magnetic force of the robot can improve the adsorption stability,but it also increases the movement resistance and reduces the operating flexibility. Reducingmagnetic force of the robot can decrease the movement resistance and increase the operatingflexibility, but it also reduces the adsorption stability. So the magnetic force has an importantimpact on the performance of underwater wall-climbing robot, and the study on adsorptiondevice has important theoretical and practical value.The variable magnetic device is a new kind of adsorption device in underwaterwall-climbing robot. And it is supported by the Natural Science Foundation of EducationDepartment of Henan Province named the study on adsorption characteristics of the variablemagnetic device in underwater robot. The developing situation of various adsorption devicesin wall-climbing robots was introduced systematically, and an underwater variable magneticdevice prototype was developed successfully. The mechanical structure, force status, drivingperformance and control mode of the device were studied for the need of underwater workfeatures.At first, the characteristics of the adsorption ways in wall-climbing robots at home andabroad were described, and the research and application status of the adsorption ways weresummarized, and a variable magnetic device that can change the magnetic force was proposedfor underwater wall-climbing robot.The working principle of the magnetic device was analyzed, and the mechanicalstructure of it was designed. The permanent magnetic adsorption was used on the device, andRare-earth material Nd-Fe-B was chose as permanent magnet. The performances of variousdriving ways were analysed, and the stepper motor was used to drive the magntic device. Thescrew-nut institutions were chose as transmission mechanism to translate the rotary motion ofthe motor into linear motion. The sealing system in the magnetic device was designed, theO-ring was selected for static seal and the glay-ring was used for dynamic seal.The magnetic device was analyzed mechanically to establish the mechanical model ofavoiding overturn, slide and fall on hull. And the mechanical model was simulated byMATLAB and verified by experiment. So we could conclude that the slide is the main problem that needs to be solved for the magnetic device and the adsorption force of themagnetic device should not less than the maximum magnetic force of anti-slide.The finite element analysis and dynamic simulation of the magnetic device wereprocessed. The finite element model of permanent magnet was established in the ANSYSsoftware. A magnetic force curve at different gaps was obtained by finite element analysis,and it also was verified by experiment. The dynamic modle was established in theAdams/view software. And the magnetic force was loaded into the modle to carry outdynamic analysis. The torque and power of the device were acquired by the analysis.The control principle of the magnetic device was introduced, and the hardware andsoftware of control system was designed, and the control system was tested by experiment.The variable magnetic device will promote the development of adsorption device inunderwater wall-climbing robot, so it has the important significance for improving theadsorption performance of underwater wall-climbing robot. |
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