With modifications made to the general slider design (described in the previous post), we decided to work on printing out the pieces for the rest of the fingers (middle, ring, thumb and pinky). Once that was done, we also tried to assemble the whole exoskeleton together. This was done by using PE braided fishing line threaded through the various parts. The structure of the glove was also held together by pieces of felt and Teflon tubes, as shown in Figure 1. One important point we had to consider during the assembly of the main structure of the glove is wire routing. The PE braided fishing line is meant to imitate the tendons of our fingers, hence they must be pulled along a similar route as our tendons in order to create motion of our fingers. As such, we have come up with a design that allows for that as shown in Figure 1. This solution makes use of techniques of soft robotics.
Figure 1. First assembly of our exoskeleton
The assembled exoskeleton allowed for the natural movement of the hands as shown in the video below.
Do take note that in the above video, not all the fingers were moving as we faced some problems in making our finger parts “snap-on”. We had initially purchase silicone rings and planned to cut them so that they could be snapped on. However, the silicone rings proved to be too flexible and were not able to hold the finger parts down well, which affected the performance of the device. A visualisation of this problem can be seen in the video below.
Moving forward, we would have to think of a better way to snap the finger parts onto the spastic hands of patients.