NOTE: If there are any pieces missing please contact me and I'll endeavour to track them down!
This was part of an experiment to see if I can replicate some of the muscle/tendon/bone structure in a humanoid form. It is not intended to mimic the body accurately but more to find a balance between current robotics and biological structures. I took inspiration from tensegrity principles as well (particularly in the spine).
I designed the parts so that they could be printed on a Form2 SLA printer. The muscle/tendon stand ins are made of silicone. Dragon skin 10 for the shoulder joints, and Shore A 40 silicone resin for the spinal joints. The silicone parts were cast in shallow moulds, with a break apart feature, that allows a variety of lengths to be made, and also reduce the damage done to the tendon when removing it from the mould.
The tendons slip over the mushroom like anchor points on the bones.
As it was very much an experiment I added more anchor points than was needed to the ribcage.
The prototype worked very well. The tendons around the sockets held the bones in their relative places, and also provided a wide range of movement that mimicked human shoulder movement.
You can see some of the movement at https://www.youtube.com/watch?v=eh9nBmOwDEU
I wasn't able to devote more time to this test and I had wanted to move onto silicone artificial muscles, which I would add to a larger model. But so far I have not been able to run enough tests with them.
Post processing was quite straightforward. bones followed the usual Form 2 part clean up procedure. I only needed to sand the ball and socket joint in order to reduce the friction.
For the silicone I mixed up and degassed the silicone. I added them to the moulds and let them set. I removed the mould half connectors, in order to break apart the mould and remove the silicone without damaging it.
I used Fusion 360 for the design work. This allowed me to define parameters, such as the anchor size. It also allowed me to keep the joints between the vertebrae the same whilst, giving the entire spine a curvature that copies the human spine.
I would really like to work on the next round of designs like this. I want to add soft robotic actuators and allow it even more organic and human like movement.
I would be very interested in speaking to anyone who has experience getting funding for any work like this. I work freelance, so it can be tough to have both time and money at the same time to develop this project. Any guidance, tips, contacts anyone can give would be very helpful.