Yesterday I thought that I should use something other than motors and started looking into magnets and electromagnets. I was already ready to buy solenoids, but the next morning while I was reading about wireless charging and excessive heat, I remembered that solenoids also become hot while they work.
Why? You need to supply constant power to solenoids in order to keep their position, while the motors stay in their position. Right? Only motors that already have gears inside—gear motors.
Then I discovered a new development that people try to make popular—silicone inflatable robots, also known as soft robots. They try to be more flexible, light, and modern. But they heavily depend on air, pump, compressor, valves, and hermetic connections. Usually, this approach is very slow unless you use a pneumatic system. It’s so early in development. I don’t see one autonomous prototype. I don’t see a complete leg or arm, even not saying about full body.