DESIGN, CONSTRUCTION AND FIELD DEMONSTRATION OF EXPLORER: A LONG-RANGE UNTETHERED LIVE GASLINE INSPECTION ROBOT SYSTEM

Abstract

The goal of this program is to construct and demonstrate EXPLORER, a modular, remotely controllable, self-powered, untethered robot system for the inspection of live gas distribution 150 mm (6-inch) to 200 mm (8-inch) diameter mains. The system, which was designed in an earlier effort, is built in a modular fashion in order to accommodate various components intended to accomplish different inspection, repair, sample retrieval, and other in-pipe tasks. The prototype system to be built under this project will include all the basic modules needed by the system, i.e. the locomotion, power storage, wireless communication, and camera. The camera, a solid-state fisheye-type, is used to transmit real-time video to the operator that allows for the live inspection of gas distribution pipes. This module, which incorporates technology developed by NASA, has been designed, constructed and tested in the earlier effort. In the current effort, the full prototype system will be tested in the laboratory followed by two field demonstrations in real applications in NYGAS member utilities' pipes. The purpose for EXPLORER is to be able to access live gas mains, insert the system in the piping network, and remotely drive it within the gas main and its laterals through distances of five to ten thousand feet. Its adaptable locomotion system allows the robot to function through varying diameter pipes (150 - 200 mm or 6- to 8-inches) and is powered via on-board battery-banks. The presence of fish-eye cameras in both ends of the robot allows the operator to view the forward and circumferential views of the internals live using an above-ground TV. Communication takes place via wireless link between the robot and the launch-chamber used to insert/retrieve the system. This link is based on commercial technology presently employed in wireless telecommunication networks. Communication over long distances as well as battery re-charging will be accomplished without retrieving the robot but through the use of auxiliaries, to be developed in a follow-on phase, that will allow insertion of additional antennas and battery recharge plugs into the pipe under live conditions through inexpensive keyhole sized excavations. The proposed system significantly advances the state of the art in inspection systems for gas distribution mains, which presently consist of tethered systems of limited range (about 500 ft form the point of launch) and limited inspection views. Also current inspection systems have no ability to incorporate additional modules to expand their functionality. This development program is a joint effort among the New York Gas Group (NYGAS; a trade association of the publicly owned gas utilities in New York State), the Jet Propulsion Laboratory (JPL), the Johnson Space Center (JSC), Carnegie Mellon University's (CMU) National Robotics Engineering Consortium (NREC), and the US Department of Energy (DOE) through the National Energy Technology Laboratory (NETL). The DOE's contribution to this project is $499,023 out of a total of $780,735 (not including NASA's contribution). The present report summarizes the accomplishments of the project during the first six months since funding from DOE commenced. The project has achieved its goals for this period as outlined in the report. Currently the fabrication of the prototype is in progress and it should be completed by late-summer 2002. Testing of the prototype in the lab is expected to be completed by November 2002, to be followed by two field demonstrations in early 2003.