Comparison of control strategies for an EMG controlled orthotic exoskeleton for the hand

To restore dexterity to paralyzed hands, we have designed and constructed a lightweight, low-profile orthotic exoskeleton controlled by the user's residual electromyography (EMG) signals. In this paper, we compared several simple strategies to control the orthotic device for a quadriplegic (C5/C6) subject. When contralateral arm control was employed, we found that a simple on/off strategy allowed for faster interaction with objects, while variable control provided more controlled interactions, especially with deformable objects. Furthermore, we designed a control strategy that allowed for a natural reaching and pinching sequence without the use of the contralateral arm. We validated that the EMG signal from the ipsilateral biceps could be used to develop an extremely reliable natural reaching and pinching algorithm. This evaluation showed that different control strategies may be appropriate for different situations, and further investigation on the natural algorithm is crucial.

[1]  R. Kirsch,et al.  EMG-based prediction of shoulder and elbow kinematics in able-bodied and spinal cord injured individuals. , 2000, IEEE transactions on rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society.

[2]  K. Kuribayashi,et al.  An upper extremity prosthesis using SMA actuator , 1992, [1992] Proceedings IEEE International Workshop on Robot and Human Communication.

[3]  Katsutoshi Kuribayashi,et al.  A discrimination system using neural network for EMG-controlled prostheses-Integral type of EMG signal processing , 1993, Proceedings of 1993 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS '93).

[4]  Tetsuji Yoshida,et al.  "Skil Mate" wearable exoskeleton robot , 1999, IEEE SMC'99 Conference Proceedings. 1999 IEEE International Conference on Systems, Man, and Cybernetics (Cat. No.99CH37028).

[5]  Steven B. Kenney,et al.  Hybrid Arm Orthosis , 1990 .

[6]  D. Berbrayer,et al.  A Myoelectrically Controlled Wrist-Hand Orthosis for Brachial Plexus Injury , 1992 .

[7]  D. W. Repperger,et al.  Development of a mobility assist for the paralyzed, amputee, and spastic patient , 1996, Proceedings of the 1996 Fifteenth Southern Biomedical Engineering Conference.

[8]  Ralph O. Buchal,et al.  The SMART Wrist-Hand Orthosis (WHO) for Quadriplegic Patients , 1993 .

[9]  Toshio Tsuji,et al.  EMG pattern classification for a prosthetic forearm with three degrees of freedom , 1992, [1992] Proceedings IEEE International Workshop on Robot and Human Communication.

[10]  N. Benjuya,et al.  Myoelectric Hand Orthosis , 1990 .

[11]  Robert F. Kirsch,et al.  EMG-based motion intention detection for control of a shoulder neuroprosthesis , 1997, Proceedings of the 19th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. 'Magnificent Milestones and Emerging Opportunities in Medical Engineering' (Cat. No.97CH36136).