Abstract: One prototype of wireless autonomous wheeled traction robot for internal inspecting system of seabed oil pipeline is developed. The mechanism structure and operation principle of robot are introduced, and its moving dynamic characteristics are also analyzed. The robot has link structures of whole active wheels with motor and transmission mechanism built in it, which includes six driving arm links and a body frame. One couple of driving wheels are attached directly at the end of each driving arm link and can be controlled by an independent motor. The six driving arm links which are fixed circumferentially with 60° apart on the outside of body frame, are arranged by alternation of front and rear and interleaving in direction of axis, which form the driving mode of six independent wheels and double sections. The modulating mechanisms of closing force are located on the ends of central body frame of robot, to create active contact or disengage of driving wheels with the inner surface of pipe. The robot features with small size of volume, compact structure and big Traction force.The experiments to verify the traction force of robot are conducted, as a result, it is a desirable traction device for the inspecting system of small diameter pipeline.

Key words: Driving arm, Dynamic characteristics, Independent wheel, Traction robot