Design considerations and human-machine performance of moving virtual fixtures

Haptic virtual fixtures have been shown to improve user performance and increase the safety of robot-assisted tasks, particularly for surgical applications. However, little research has studied virtual fixtures that provide moving force constraints based on motion of the environment, e.g., organ movement due to heartbeat or respiration. This work discusses design considerations of moving forbidden-region virtual fixtures and presents two methods of implementation: predicted-position and current-position virtual fixtures. Human subject experiments were performed to determine the effectiveness of moving virtual fixtures when interacting with an object in motion using a teleoperator. Results show that moving virtual fixtures can help improve user precision and decrease the amount of force applied.