A Standardized Vibro-tactile Sensory Feedback System For Upper-limb Prostheses.

This work describes the design and evaluation of a vibro-tactile sensory feedback system with standardized stimuli for force perception. Five vibration intensities corresponding to five force levels were identified by a calibration experiment on six intact-arm subjects. Eight of ten intact-arm participants and the trans-radial amputee subject learned to distinguish the force levels within one hour of force recognition training. Augmenting visual feedback with vibro-tactile feedback in a force replication task did not significantly affect performance. Participants' force replication performance did not significantly degrade one hour after training. Participants performed significantly worse when using only vibro-tactile feedback after a single training session. However, the amputee subject after four daily training sessions achieved a 93.3% success rate in the force recognition task and 73.3% in the force replication task with only vibro-tactile feedback, approaching their performance with visual feedback. These results suggest that it is possible to train prosthesis users to evoke and control force levels almost as well with vibro-tactile feedback as with visual feedback. This technology could play a key role in reducing prosthesis abandonment and enhancing the quality of life of upper-limb amputees.