Dynamic Analysis Of A Cable-climbing Robot

Nowadays,cable-stayed bridge and suspension bridge are widely used for their great economic value.Meanwhile,the safety of bridge can not be ignored.As the main bearing parts of bridge,cables are always affected by extreme environment such as wind and rain vibration,needing regular maintenance.The application of cable-climbing robots can emancipate the workers from dangerous aloft work.There are some cable-climbing robots put into use both China and abroad.However,the special Researching on dynamic problem is less.On the one hand,the vibration of cable will change when robot is climbing on it.On the other hand,vibration will influence the climbing ability of robot.So the paper will focus on coupled vibration of robot and cable.The details include:(1)Overall design of the robot system.Analysis of the mechanical structure.Selection of motor and transmission.Finding the decisive factors of recovery mechanism.Discussing of control system.(2)Analysis of the climbing ability,preventing derailment and obstacle crossing of robot.Researching on the preventing skidding and deviation as well as the relationship between them.Discussing the parameters of obstacle crossing.Researching on the relationship between obstacle crossing and position of driving wheel.(3)Researching on resonance between robot and cable.Solving the natural frequency of the robot-cable system by Rayleigh quotient.Solving the natural frequency of the frame by finite element method.Discussing the structural vibration and control method.Designing the damper through state space theory.(4)Researching on vibration response of robot-cable system,describing it by vibration string equation with lumped mass.Researching on the response under transient exciation by analytic method and discrete method respectively.Giving the simulation on basis of discrete method.Researching on the maximum amplitude of cable when robot is in different position.Establishing similarity model.Studying the similarity experiment.(5)Experimenting on robot in the laboratory.Researching on climbing ability,safe recovery,climbing speed by experiment.Establishing the vibration-climbing platform.Discussing the design of platform.Studying on the climbing ability under vibration.Some methods in this paper are also valuable to other cable-climbing robots.