Behavior-based control for time-delayed teleoperation

Remote control of robotic manipulation has applications in undersea, shallow space and low bandwidth communication environments. Communication delays on the order of several seconds can occur during space operations that use relay stations, undersea operations using acoustic communication channels, or when significant computational delay exists. This system is also applicable to time varying time delays as experienced when the Internet is used as the medium of communication. The use of supervisory control to address the time delay problem requires a remote manipulator to exhibit some degree of autonomy. This autonomy is necessary to minimize the contribution of communication delay time to task completion time and to relieve the operator of the responsibility for contact control. This dissertation examines the use of behavior-based or subsumption architecture control to provide the required autonomy for the remote manipulator. Behavior-based controllers demonstrate desirable features including reliability and robust operation in unstructured environments and, when used in conjunction with operator direction, avoids the need for higher level representations which do not fit well into the architecture. We develop a model for communications between the operator and the behavior-based controller and define the human-machine interface for operator direction. We demonstrate the supervisory control system on a GRASP Laboratory mockup of a slicing task performed during a satellite repair operation. In this task a robot cuts securing tape along the seams of the panels of a thermal protection blanket. We tested the validity of the supervisory control system by performing controlled experiments using untrained operators. Quantitative and qualitative results demonstrate the supervisory control concept is a practical and viable solution to the time delay problem.