Abstract

A patent pending new class of robots is presented for traversing networks of pipes with numerous elbows, joints, and diameter changes, for fully autonomous tasks including internal inspection, exploration, and mapping. The robots proposed have three or more wheels whose center points all lie within a Robot Center Plane. The robots have minimal complexity, maximal maneuverability, static stability, and fault tolerance, with:

Motors for propelling themselves down the pipe,

A means for accurately controlling themselves in roll,

Springs that press the wheels at three or more alternating points of contact against opposite sides of the pipe wall, thus causing the Robot Center Plane to subsume the centerline of the pipe, and passively stabilizing the robot orientation in pitch and yaw, allowing the robot to travel stably, without feedback, within a pipe at any orientation with respect to gravity, and

A novel means for negotiating both pipe elbows and pipe joints (Tee joints, Wye joints, etc), as well as substantial pipe diameter changes.

Algorithms to exhaustively route such vehicles through complex networks of connected pipes will also be presented. This problem is relatively standard (implementing the Dijkstra, Eulerization, and Hierholzer algorithms) in the case of small pipe networks. Note that the optimal Eulerization problem in NP hard, like the traveling salesman problem; a new Eulerization algorithm is presented in this work that gives near optimal performance on small problems, and scales easily to networks with thousands of odd nodes. Recent work on extending such strategies to very large pipe networks, in which all of the pipes of the network can not be traversed by the robot on a single charge, and in fact multiple entry points to the network are necessary, will also be discussed.