# How much energy I would require to make a piston to move as fast as human muscle? [closed]

Context: Robots and exoskeletons in this fictional scenario are having a "boom" because of some random super battery that can store a lot of energy, but it can only release it in really small quantities during a long period of time. So the idea is that it can power an exoskeleton, but you need a pneumatic/hydraulic cylinder to make it useful. Like a normal battery, but with a really long duration span.

The thing is that I can't make heads of the amount of energy/bars I would require to store in a pressure cylinder (hydraulic or pneumatic) in order to make cylinder actuators (hydraulic/pneumatic pistons) to work as fast (if not faster) than the human muscle.

After all, it is about military exoskeletons that need to help the squishy hummies to survive during combat.

Don't worry too much about the battery itself, but about the forces (if you can), for example "if we take into consideration AA batteries, you would require the cylinder to be this size", or something like that.

• linear actuators and pistons are two very different things, linear actuators are powered by electricity instead of pressure.
– John
May 22 at 23:39
• Which muscle? How light is the piston? If the piston is light enough then then a trivially minimum amount of energy. It seems like you're not asking about the amount of energy to move a piston, but about the amount of energy needed to power a suite of power armor, for some unit of time. May 23 at 1:54
• It is completely unclear what you are asking. In particular, the phrase "the amount of energy over bars I would require to store in a hydraulic pressure cylinder in order to make the cylinder actuactors (hydraulic pistons) to work as fast if not faster than human muscle" is completely opaque. In a first approximation, any hydraulic system will respond very much faster than any animal muscle -- the speed of sound in hydraulic oil is very much greater than the speed of neural transmission. May 23 at 3:40
• P.S. I think that I understand the problem to be that you have a battery technology which provides very large capacity, but limited maximum discharge current. If my understanding is correct, then the requirement to increase the maximum discharge current is an electrical problem, to which any normal engineer will seek and design electrical solutions instead of going into hydraulics or pneumatics, and have the limited current battery charge a supercapacitor or a small battery with large maximum current. Electrical solutions have the great advantage of having no moving parts... May 23 at 3:48