Sensorimotor-inspired Tactile Feedback and Control Improve Consistency of Prosthesis Manipulation in the Absence of Direct Vision

TL;DR

This study introduces a sensorimotor-inspired tactile feedback system for prostheses that enhances manipulation consistency without visual cues, mimicking natural reflexes and haptic perception to improve user performance.

Contribution

The paper presents a novel tactile feedback and reflex control system for prostheses, inspired by natural sensorimotor functions, to improve manipulation consistency without relying on vision.

Findings

Participants with tactile feedback showed more consistent performance.

Tactile feedback increased grasp stability and object handling.

Reflex control reduced over-grasping and slipping incidents.

Abstract

The lack of haptically aware upper-limb prostheses forces amputees to rely largely on visual cues to complete activities of daily living. In contrast, able-bodied individuals inherently rely on conscious haptic perception and automatic tactile reflexes to govern volitional actions in situations that do not allow for constant visual attention. We therefore propose a myoelectric prosthesis system that reflects these concepts to aid manipulation performance without direct vision. To implement this design, we built two fabric-based tactile sensors that measure contact location along the palmar and dorsal sides of the prosthetic fingers and grasp pressure at the tip of the prosthetic thumb. Inspired by the natural sensorimotor system, we use the measurements from these sensors to provide vibrotactile feedback of contact location and implement a tactile grasp controller that uses automatic reflexes to prevent over-grasping and object slip. We compare this system to a standard myoelectric prosthesis in a challenging reach-to-pick-and-place task conducted without direct vision; 17 able-bodied adults took part in this single-session between-subjects study. Participants in the tactile group achieved more consistent high performance compared to participants in the standard group. These results indicate that the addition of contact-location feedback and reflex control increases the consistency with which objects can be grasped and moved without direct vision in upper-limb prosthetics.