Robotics and Intelligence Systems >> Remote Characterization >> Limitations to the Teleoperated Approach

Remote Characterization

Limitations to the Teleoperated Approach

Although the 2001 robotic deployment offered a means to reduce human exposure, it did not fully remove the human from the hazardous environment or make it possible for a single human to control the robot. In fact, the baseline survey required only three people, whereas the RGL&IID required six. This high ratio of humans to robots is what has led the INL to explore the possibilities provided by sliding robot autonomy.

Teleoperation requires high-fidelity video, reliable, continuous communication, and costly, potentially dangerous efforts to instrument the environment a priori. As a mechanical ‘subordinate,’ the robot was dependent on continuous input from a human and was poorly equipped to cope with communication failures or changes in operator workload. In fact, while training within a mock-up facility, operators lost control of the vehicle due to a communication failure. Since the last command received by the robot before communications were lost had been a forward velocity command, the robot continued to navigate across the room and actually ran right through the wall of an adjacent test bed environment. The robot’s control system was immediately changed to have a "watchdog" system that halted the robot once it recognized that communications had failed.

But communication proved to be the limiting factor governing human-robot interaction during the teleoperated deployment. Thick concrete shielding, typical to radiological controls, made it extremely difficult for high-bandwidth communication to support the strictly teleoperated system. As a result, it was necessary to place a large antenna directly into the opening of the building. As the robot traveled further from this antenna, the possibility of communication dropouts increased. In fact, operators completely lost contact with the robot at one point during the deployment when the robot traveled out of range. Since the robot was merely a passive tool, it was unable to reorient itself or attempt to reestablish communication. If humans had been unable to enter the environment, the robot would have been lost and unable to complete its task. Fortunately, it was possible to move the antenna further into the doorway of the building and communication was reestablished.

The 2001 RGL&IID deployment required weeks of preparation including training operators in mock-up environments. Early on, these training exercises indicated that cameras on the robot would not show the immediate obstacles surrounding the wheels - the very obstacles that posed the greatest threat. As a result, it was necessary to instrument the environment beforehand with elevated cameras. These cameras were tethered to allow sufficient bandwidth for high-resolution video and were set up in the environment by humans. Human placement of tethered cameras is a common practice in nuclear remote inspections throughout the DOE complex. This drawback to teleoperated approaches is further pronounced by the fact that these cameras must be bagged, resulting in additional contaminated waste once the operation is complete.

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