A virtual myoelectric prosthesis training system capable of providing instructions on hand operations

Go Nakamura,Futoshi Mizobe,Takaaki Chin,Akito Masuda,Taro Shibanoki,Yuichiro Honda,Yuichi Kurita,Toshio Tsuji

doi:10.1177/1729881417728452

Abstract

This article proposes a virtual hand and a virtual training system for controlling the MyoBock—the most commonly used myoelectric prosthetic hand worldwide. As the virtual hand is controlled using the method also adopted for the MyoBock hand, the proposed system provides upper-limb amputees with operation sensibilities similar to those experienced in MyoBock control. It can also display an additional virtual hand for the provision of instructions on hand operation, such as the recommended posture for object grasping and the trajectory desirable to reach a target. In virtual hand control experiments conducted with an amputee to evaluate the proposed virtual hand’s operability, the subject successfully performed stable opening and closing with high discrimination rates (89.3±6.65%), thanks to the virtual hand’s incorporation of the MyoBock’s operational characteristics. A training experiment using the proposed system was also conducted with eight healthy participants over a period of 5 days. The participants were asked to perform the box and block test using the MyoBock hand in a real environment on the first and final days. The results showed that the number of blocks transported in 1 min significantly increased and that the participants using the instruction virtual hand changed the orientation of the hand approaching blocks from vertical to lateral. The outcomes of the experiment indicate that the proposed system can be used to improve MyoBock hand control operation both quantitatively and qualitatively.

Highlights

A number of studies on myoelectric prosthetic hands[1,2,3,4,5,6,7] which are controlled based on electromyogram (EMG) signals, have been conducted to support the daily living of upper-limb amputees
Task training with the myoelectric prosthesis is necessary before the unit can be prescribed
The average discrimination rate indicates that the subject successfully performed stable opening and closing control with high discrimination rates. This is considered attributable to the fact that the operation sensibilities were similar to those of the subject’s control of the MyoBock hand in everyday life, thanks to the similarity between the proposed virtual hand (VH)’s motion threshold and angular velocity of opening/closing to those of the MyoBock hand. These results indicate the feasibility of virtual reality (VR) environment training without incongruity using the proposed VH with control based on the method and operational characteristics of the MyoBock hand

Summary

Introduction

A number of studies on myoelectric prosthetic hands[1,2,3,4,5,6,7] which are controlled based on electromyogram (EMG) signals, have been conducted to support the daily living of upper-limb amputees. To control these prostheses naturally, several months of training under the instruction of doctors and therapists are required.[8]. Long-term training is required until users can perform tasks naturally

Methods

Results

Conclusion