On the relationship between autonomy, performance, and satisfaction: Lessons from a three-week user study with post-SCI patients using a smart 6DOF assistive robotic manipulator

The UCF-MANUS, a vision-based 6DOF assistive robotic arm, has been designed to aid individuals with arm function limitations to complete tasks of daily living that they would otherwise be unable to complete themselves. This paper reports a small dual cohort pilot study with traumatic spinal cord injured (SCI) subjects designed to investigate the utility of the UCF-MANUS for these subjects. Pick-and-place ADL tasks were defined and users trained and tested with the system for three weeks during which they controlled the robot either through a manual or an autonomous (supervised) mode of operation. Baseline characteristics (pre-study), quantitative performance metrics (during study) and psychometrics (poststudy) were obtained and statistically analyzed to test a set of hypotheses related to performance and satisfaction with the two control modes. It was seen that manual interaction showed more variability and inefficiency in performance metrics as compared to autonomous operation. Suprisingly the latter mode, however, did not lead to better measures for user satisfaction. A discussion is provided to explain the results. Based on qualitative feedback and quantitative results, possible directions for system design are presented in order to concurrently achieve better performance and satisfaction outcomes.