Step 7: Other Possibilities
The thumb pic shows the muscle relaxed.
The muscles I have made so far are pressure muscles. I made them this way because they are the simplest type of actuator. Vacuum muscles that have larger volume cavities that collapse under a vacuum can also be made. This makes them closer to animal muscles that can be used with "tendons" to mimic natural motions.
It should eventually be possible to print the skeleton, muscles, and skin for a robot. This would make for more economic and efficient robots.
Extremely Small Robots
My main interest is in building small robots one foot long or less. These low pressure muscles are ideal for that. It may even be possible to make extremely small microscopic muscles by painting or spraying them on.
Smaller and quieter pumps will be needed to make extremely small robots. There are several robot researchers working on small chemical generators that create gas to provide the pressure.