BACKGROUND: Many surgical robotic interfaces allow users to interact with robots over a wide potential range of motion, yet variation in operator performance across a range of motion remains unexamined. This research identifies and explores a new construct, the surgeon's 'comfortable working envelope' within the available range of motion, as a factor in surgical robotic interface design. METHODS: Task accuracy and completion time for a simple aimed movement task were analysed as a function of participant hand positions obtained via infrared motion tracking. RESULTS: Hand positions outside the 'comfortable working envelope' led to a 20% increase in error magnitude. With respect to the overall input device range of motion, there were large variations in performance, up to 31% difference in error magnitude and 11% difference in movement time. CONCLUSIONS: These results suggest that advanced surgical robots should have intelligent re-indexing strategies. Alternatively, the robot's control gain should adaptively change with respect to hand position to normalize a surgeon's performance throughout his/her working volume. 2007 John Wiley & Sons, Ltd.
BACKGROUND: Many surgical robotic interfaces allow users to interact with robots over a wide potential range of motion, yet variation in operator performance across a range of motion remains unexamined. This research identifies and explores a new construct, the surgeon's 'comfortable working envelope' within the available range of motion, as a factor in surgical robotic interface design. METHODS: Task accuracy and completion time for a simple aimed movement task were analysed as a function of participant hand positions obtained via infrared motion tracking. RESULTS: Hand positions outside the 'comfortable working envelope' led to a 20% increase in error magnitude. With respect to the overall input device range of motion, there were large variations in performance, up to 31% difference in error magnitude and 11% difference in movement time. CONCLUSIONS: These results suggest that advanced surgical robots should have intelligent re-indexing strategies. Alternatively, the robot's control gain should adaptively change with respect to hand position to normalize a surgeon's performance throughout his/her working volume. 2007 John Wiley & Sons, Ltd.