nSIR: A Novel Passive-Active Intelligent Moving Mechanism for Sewer Inspection Robots

In the current sewer pipe inspection technology, all commercial sewer inspection robots have a poor mobility function to pass any kind of pipe-bends such as curves and junctions so that those robots are only capable to move into the straight pipes. In this paper, we describe the design, modeling, simulation and implementation of a compact and novel moving mechanism, called "nSIR mechanism", with capability of moving into the straight pipe and passing different kinds of pipe bends without need to any intelligence of the controller or sensor reading. The design is based on the concept of passive adaptation of robot wheels to the bends in the pipe. This is accomplished by proper wheels orientation and passive damping of springs. In addition, this moving mechanism has capability to pass the different size of pipes in diameter even from a bigger diameter pipe to smaller diameter and also can pass obstacle and go down step. After describing the principle of nSIR mechanism, this paper gives experimentally that a prototype of our robot "KANTARO" includes of this mechanism can realize all the above movement functions.