Vision assisted control for manipulation using virtual fixtures

The "steady hand" concept is a way of providing assistance for direct manipulation by applying constraints on the motion of a tool shared by a user and a robot. In this paper, we explore in detail one family of constraints: virtual fixtures for use in path following tasks. Vision is used to sense the desired path, and then the robot encourages motion toward and along the path through a direction-based control law. This "soft" virtual fixture allows lows the user to move in other, non-preferred directions, maintaining the user's sense of autonomy and control. Experimental results show that user performance in assisted path following improves with virtual fixture augmentation, and differs with varying fixture compliance.