Well, non-tethered artificial muscles are just artificial muscles that only need electric wiring in order to work; unlike pneumatic/hydraulic/vacuum actuators that need a external pump in order to contract.
I ask that because I want to build my own robot with soft robotics/artificial muscles.
However, all the equipment for pneumatics, vacuum and hydraulics are really expensive for robotics application (at least, where I live).
A single solenoid valve costing 88 euros for a single piston in an elevator is quite affordable, but 50 solenoid valves for 50 muscles? That would be... Really expensive.
I want to build a robot to interact with humans, and build it first and program it later, since I don't know anything about programming (probably not the best idea).
What I found until now:
Mckibben muscles that have some kind of eletroclisis-like reaction inside them, releasing gases that expand the muscle:
"Actuation of Untethered Pneumatic Artificial Muscles and Soft Robots": https://youtu.be/lOAr2nK2NLI
But they need an external source of heat in order to work, even if it is made just with water and iron, the external material still can catch on fire.
McKibben muscles that had some low boiling point fluid inside them (like ethanol) and an electric discharge boiled the liquid and the pressure made by the vapor expanded the muscle. But hey, who wants to mix ethanol with electricity with a machine made to interact with humans?
"New fully electric artificial muscle for prosthesis and robots - 1st version": https://youtu.be/89AmyJjYdzQ
- I also found dielectric artificial muscles, however, they need a LOT of energy to work, 10 kv just to contract is not the ideal to interact with humans.
"Realizing the potential of dielectric elastomer artificial muscles": https://youtu.be/LWDRlfruSBM
Of course, there is also fishing line artificial muscles, but these need an specific type of nylon that are coated in silver (198 dollars a single coil and it just contracts 8% of its length).
And, for the last one, this electromagnetic muscle that is just a bunch of electromagnets stacked together. These are easy to make and the ones I will more likely build, since It is really cheap and easy to make. But I don't know for sure if it will work in a robot the size of a human being, since electromagnets are heavy and not very powerfull unless you put kv of power.
“Electromagnetic Artificial Muscle 2020”: https://youtu.be/ZINr9ssGOvE
So? Do you guys know any artificial muscles that could be made/bought and are easy to use?
And yes, I know I could build if servos using elastic lines, but it would still not be soft enough to interact with human beings, just safe. Also, I asked on chemistry.stackexchange for opinions for chemical reactions, but they just downvoted me to hell and said I should just work with hydraulics.