8Choi H R, Ryew S M. Robotic system with active steering capability for internal inspection of urban gas pipelines [J] .Mechatronics, 2002, 12 (5): 713 - 736.
9Hayashi I,lwatsuki N,lwashina S.The running characteristics of a screwprineiple microrobot in a small bent pipe[C] //IEEE Sixth International Symposium on Micro Machine and Human Science.Nagoya,Japan,1995:225-228.
10Campion G,Bastin G D,Andrea-Novel B.Structural properties aclassification of kinematics and dynamic,models of wheeled mobile robots[J].IEEE Transactions on Robotics and Automation,1996,12(1):47-62.