Maintaining Communication Link for a Robot Operating in a Hazardous Environment

Abstract : Communication is usually the limiting factor governing human-robot interaction during teleoperated operation in nuclear storage facilities. Thick concrete shielding makes it extremely difficult to maintain high- bandwidth radio communication. The same problem is encountered in urban law-enforcement applications and in hostile military operations. Hard cable tethers are cumbersome, require large spools for extended range, and are not appropriate for most applications besides urban explosive-ordnance-disposal. Thinner optical fibers, even reinforced, have been found to be fragile in field use in the Afghanistan and Iraq theaters. The cables often get run over by the robot as it is maneuvered around obstacles. Snagging and stretching of the fiber around corners often cause signal loss. These problems may be mitigated if the robot can assume some of the lower-level functions, such as obstacle avoidance and local path planning. This would reduce the amount of data traffic, and allow for the use of lower-frequency, lower-bandwidth radio links that have better wall penetrating capability. However, we have found that in critical missions, the soldier/operators preferred complete control of every aspect of the robot, minimizing any chance for surprises. Thus a high-bandwidth (video rate) communication link is required.