1. A new way of myoelectric control A new way of myoelectric control MyoPro project Daphne van Baal Hans Rietman, Laura Kallenberg 25 september 2009

2. Roessingh Research and Development, Enschede, the Netherlands 2 Introduction Low usage myoelectric prosthesis AdvantagesDisadvantages Non-invasive No straps or harnesses Use of remaining muscles Limited selectivity Lack of intuitive control Lack of sensory feedback

3. Roessingh Research and Development, Enschede, the Netherlands 3 Goal Improve the control of a myoelectric forearm prosthesis by increasing the number of degrees of freedom using multi-channel surface electrodes

4. Roessingh Research and Development, Enschede, the Netherlands 4 Experimental protocol Ten healthy male subjects One forearm amputee Forty small electrodes in grid Eight isometric contractions

5. Roessingh Research and Development, Enschede, the Netherlands 5 Isometric contractions Flexion of wristExtension of wristFlexion of fingersExtension of fingers Abduction of wristAdduction of wristSupination of forearmPronation of forearm

6. Roessingh Research and Development, Enschede, the Netherlands 6 Data analysis Data selection of active contractions Time periods of 200 milliseconds Root mean squared (RMS) value Subject specific classification Simple robust classifier (kNN)

7. Roessingh Research and Development, Enschede, the Netherlands 7 RMS-level images

8. Roessingh Research and Development, Enschede, the Netherlands 8 Robust classifier Training setTest set

9. Roessingh Research and Development, Enschede, the Netherlands 9 Results Output Input FFFEPSABADWEWF Finger flexion99.940.030.010.02 Finger extension0.0199.890.01 0.08 Pronation99.960.04 Supination0.01 99.850.030.020.080.01 Wrist abduction0.020.0199.940.020.01 Wrist adduction0.0199.970.01 Wrist extension0.020.030.020.100.0199.830.01 Wrist flexion0.020.050.0199.93

10. Roessingh Research and Development, Enschede, the Netherlands 10 Continuous results

11. Roessingh Research and Development, Enschede, the Netherlands 11 RMS-level images amputee

12. Roessingh Research and Development, Enschede, the Netherlands 12 Results amputee Output Input FFFEPSABADWEWFABPADS Finger flexion 100.0 Finger extension 99.280.480.25 Pronation 99.620.020.130.23 Supination 99.640.130.060.17 Wrist abduction 99.730.060.21 Wrist adduction 0.080.250.0499.560.020.06 Wrist extension 0.020.170.1199.640.06 Wrist flexion 0.100.0299.89 Wrist ab & pro 0.190.340.0699.41 Wrist ad & sup 0.6199.39

13. Roessingh Research and Development, Enschede, the Netherlands 13 Conclusion Offline classification –normally limbed:99.9% –amputee patient:99.6% Online classification –normally limbed:93.4% Up to ten movements can be distinguished (five degrees of freedom)

14. Roessingh Research and Development, Enschede, the Netherlands 14 Future Validation: more measurements with amputees Additional patient specific contractions Random-ordered contractions Simultaneous control of different contractions Force level analysis for proportional control

15. Roessingh Research and Development, Enschede, the Netherlands 15 Questions? For more information: www.myopro.nl