The use of telerobots in remote locations allows humans to extend their capabilities to distant and hazardous environments. Although safer for the operator, this extension of capabilities comes at a price. Due to communication across great distances, experiencing time delays of up to several seconds is common. Any time delay in the human/robot interaction can significantly degrade the effectiveness of operator control. This paper will looks at two common instances of human-in-the-loop command of robots: command of vehicle motion and command of a manipulator to perform an assembly task. Results from three studies are summarized to show the degradation in performance caused by varying levels of time delay.

Space and underwater vehicles with robotic arms can severely tax the capability of conventional control systems. Submersible vehicles used in neutral buoyancy simulation are subject to even greater demands since they must simulate the dynamics of spacecraft in orbit as well as function as a remotely-operated underwater vehicle. In this report, the onboard control architecture, human-machine interface, and vehicle/operator communications are described for one such vehicle in operation at the University of Maryland Neutral Buoyancy Research Facility (NBRF). The Ranger Neutral Buoyancy Vehicle (RNBV) exemplifies the high-dimensional, computationally intensive nature of the current fleet of autonomous underwater vehicles while its complement of four manipulators exceeds the capabilities of most remotely operated vehicles in service today. The sensor-based, embedded onboard control system is described, and its implementation using multiple control stations is discussed.

A new paradigm is explored for controlling free-flying robots using a robot-centered coordinate strategy. The use of "dynamic" tool vectors for controlling manipulator motion is key to the development of this new approach. Variable tool vectors allow the arms to function in multiple roles, including camera positioning and self-maneuvering of the vehicle. In addition, these concepts are embodied in a resolved-rate architecture for controlling manipulators in robo-centric operations. The ranger neutral buoyancy vehicle, currently under development at the University of Maryland Space Systems Laboratory, is used to illustrate the application of this approach.