A mobile robot developed by Wuhan University for full-path hotline inspection on 220 kV transmission lines was presented. With 4 rotating joints and 2 translational ones, such robot is capable of traveling along non- ...A mobile robot developed by Wuhan University for full-path hotline inspection on 220 kV transmission lines was presented. With 4 rotating joints and 2 translational ones, such robot is capable of traveling along non- obstaclestraight-line segment and surmounting straight-line segment obstacles as well as transferring between two spans automatically. Lagrange’s equations were utilized to derive dynamic equations of all the links, including items of inertia, coupling inertia, Coriolis acceleration, centripetal acceleration and gravity. And a dynamic response experiment on elemental motions of robot prototype’s travelling along non-obstacle straight-line segment and surmounting obstacles was performed on 220 kV 1∶1 simulative overhanging transmission-line in laboratory. In addition, dynamic numerical simulation was conducted in the corresponding condition. Comparison and analysis on results of experiment and numerical simulation have validated theoretical model and simulation resolution. Therefore, the dynamic model formed hereunder can be used for the study of robot control.展开更多
A unilateral self-locking mechanism(USM) was proposed to increase the tractive ability of the inchworm in-pipe robots for pipeline inspection.The USM was basically composed of a cam,a torsional spring and an axis.The ...A unilateral self-locking mechanism(USM) was proposed to increase the tractive ability of the inchworm in-pipe robots for pipeline inspection.The USM was basically composed of a cam,a torsional spring and an axis.The self-locking and virtual work principles were applied to studying the basic self-locking condition of the USM.In order to make the cooperation between the crutch and telescopic mechanism more harmonical,the unlocking time of the USM was calculated.A set of parameters were selected to build a virtual model and fabricate a prototype.Both the simulation and performance experiments were carried out in a pipe with a nominal inside diameter of 160 mm.The results show that USM enables the robot to move quickly in one way,and in the other way it helps the robot get self-locking with the pipe wall.The traction of the inchworm robot can rise to 1.2 kN,beyond the limitation of friction of 0.497 kN.展开更多
Since the suspended sediments have severe influence on acoustic radiated field of transducer,it is significant for sonar system to analyze the influence of suspended sediments on acoustic pressure in the seafloor mini...Since the suspended sediments have severe influence on acoustic radiated field of transducer,it is significant for sonar system to analyze the influence of suspended sediments on acoustic pressure in the seafloor mining environment.Based on the KZK(Khokhlov-Zabolotkaya-Kuznetsov)equation,the method of sound field analysis in turbid water is proposed.Firstly,based on the analysis of absorption in clean water and viscous absorption of suspended sediments,the sound attenuation coefficient as a function of frequency in the mining environment is calculated.Then,based on the solution of KZK equation in frequency domain,the axial sound pressure of transducer in clear water as well as turbid water is simulated using MATLAB.Simulation results show that the influence of the suspended sediments on the pressure of near field is negligible.With the increase of distance,the axial sound pressures of transducer decay rapidly.Suspended sediments seriously affect the pressure in far-field.To verify the validity of this numerical method,experiment is designed and the axial sound pressure of transducer with a frequency of 200 kHz and a beam width of 7.5~is measured in simulated mining experiment.The results show that the simulation results agree well with the experiments,and the KZK equation can be used to calculate the sound field in turbid water.展开更多
文摘A mobile robot developed by Wuhan University for full-path hotline inspection on 220 kV transmission lines was presented. With 4 rotating joints and 2 translational ones, such robot is capable of traveling along non- obstaclestraight-line segment and surmounting straight-line segment obstacles as well as transferring between two spans automatically. Lagrange’s equations were utilized to derive dynamic equations of all the links, including items of inertia, coupling inertia, Coriolis acceleration, centripetal acceleration and gravity. And a dynamic response experiment on elemental motions of robot prototype’s travelling along non-obstacle straight-line segment and surmounting obstacles was performed on 220 kV 1∶1 simulative overhanging transmission-line in laboratory. In addition, dynamic numerical simulation was conducted in the corresponding condition. Comparison and analysis on results of experiment and numerical simulation have validated theoretical model and simulation resolution. Therefore, the dynamic model formed hereunder can be used for the study of robot control.
基金Project(2007AA04Z256) supported by the National High-Tech Research and Development Program of China
文摘A unilateral self-locking mechanism(USM) was proposed to increase the tractive ability of the inchworm in-pipe robots for pipeline inspection.The USM was basically composed of a cam,a torsional spring and an axis.The self-locking and virtual work principles were applied to studying the basic self-locking condition of the USM.In order to make the cooperation between the crutch and telescopic mechanism more harmonical,the unlocking time of the USM was calculated.A set of parameters were selected to build a virtual model and fabricate a prototype.Both the simulation and performance experiments were carried out in a pipe with a nominal inside diameter of 160 mm.The results show that USM enables the robot to move quickly in one way,and in the other way it helps the robot get self-locking with the pipe wall.The traction of the inchworm robot can rise to 1.2 kN,beyond the limitation of friction of 0.497 kN.
基金Project(51374245)supported by the National Natural Science Foundation of ChinaProject(10C0681)supported by Education Department of Hunan Province,China
文摘Since the suspended sediments have severe influence on acoustic radiated field of transducer,it is significant for sonar system to analyze the influence of suspended sediments on acoustic pressure in the seafloor mining environment.Based on the KZK(Khokhlov-Zabolotkaya-Kuznetsov)equation,the method of sound field analysis in turbid water is proposed.Firstly,based on the analysis of absorption in clean water and viscous absorption of suspended sediments,the sound attenuation coefficient as a function of frequency in the mining environment is calculated.Then,based on the solution of KZK equation in frequency domain,the axial sound pressure of transducer in clear water as well as turbid water is simulated using MATLAB.Simulation results show that the influence of the suspended sediments on the pressure of near field is negligible.With the increase of distance,the axial sound pressures of transducer decay rapidly.Suspended sediments seriously affect the pressure in far-field.To verify the validity of this numerical method,experiment is designed and the axial sound pressure of transducer with a frequency of 200 kHz and a beam width of 7.5~is measured in simulated mining experiment.The results show that the simulation results agree well with the experiments,and the KZK equation can be used to calculate the sound field in turbid water.
