Virtual fixture architectures for telemanipulation

A forbidden-region virtual fixture (FRVF) is a computer-generated constraint that displays position or force limitations to a robot manipulator or operator, in order to prevent motion into forbidden regions of the workspace. We compare nine FRVFs on each of four common telemanipulator control architectures: position forward, position exchange, position forward/force feedback, and position exchange/force feedback. A one-degree-of-freedom telemanipulation system was used in an experiment designed to simulate users working near a known forbidden region. The metrics of tracking, safety, and submittance were used to analyze the performance of the system with six different users. The results indicate that different FRVF architectures perform best for each of the three metrics. No single FRVF scheme is the best over all metrics, so selection of an FRVF architecture should be an application-dependent weighting of the three metrics. Across all control architectures, the results indicate that a very strong FRVF at the slave device in combination with no FRVF at the master device leads to poor telepresence.