【Prosthetic Hands】12 Second Generation - Integration, Demonstration, and Summary

In the development of the second generation of the prosthetic hand, I tried something new. Some of them worked very well (like the double 8-shaped wiring), whereas the other ones (such as the wet electrodes).... let's say I learned a lot. Despite some frustrations I encountered, I managed to complete the second generation. 

In the second generation, I reduced the length of the hand by more than 80 mm. However, since the size of the base was nearly the same, the new hand seemed to be more... "robust". (By the way, I did not determine the color. The colors were the only available filaments at the moment.)

The new hand could lift a water bottle weighing over 1 kg, which was a significant improvement compared to the first generation. Nonetheless, the new EMG signals classifier was not as effective as the first ones (which was developed by the manufacturer of the MYO armband). Here is a video demonstrating the movement of the fingers.

The movement of the fingers were not as smooth as the first generation because I tried to make it move more gently, but I did not take the resistance between joints into consideration so that sometimes, the finger just stopped. 

Well.... obviously, the second generation hand was not a perfect one, but I believe that it was on the right track --  to make it a more practical. Here I summarize the primary problems.

1. The size should be reduced.

As you can see, the second generation was a lot bigger than a normal adult's hand. The size of it should be reduced so that it could look fitting on wearers' body.

2. The EMG acquisition and classification should be improved.

This was quite an obvious problem. I think a good EMG acquisition and classification system should satisfy the following features.

(a) The sensors should be easy-to-wear.

(b) The classification should be accurate and instant.

(c) The system should be able to avoid danger when a wrong classification result is presented.

In the third generation, I will combine the merits of the former generations and add some decision-making processes in the system. Hopefully these modification can really make the prosthetic hand practical and feasible in daily life.

Thank you very much for reading these articles, if your are interested in the details of the development, please feel free to leave comments.