Robotic system with active steering capability for internal inspection of urban gas pipelines

In this paper, we present a robotic system for inpipe inspection of underground urban gas pipelines. This robot is developed on the purpose of being utilized as a mobile platform for visual and Non-Destructive Testing (NDT) of the pipeline networks. The robot is configured as an articulated structure-like a snake with a tether cable. Two active driving vehicles are located in front and rear of the system, respectively. Passive modules such as a control module and other optional modules are linked between the active vehicles. It has several characteristic features superior to the others such as flexible wheeled leg mechanisms, a steering mechanism with compliance control. Especially the steering mechanism called Double Active Universal Joint (DAUJ) intrinsically prevents rolling of the robot along the driving direction and enables to control its compliance. Those features provide the robot with excellent mobility inside the highly constrained space while negotiating the complicated configurations of the pipeline networks. We outline the construction of the robot and describe its characteristic features. 2002 Elsevier Science Ltd. All rights reserved.