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# how do i figure out how much power my biped humanoid robot will need?

exactly what my title says its going to be about average human weight and it needs to have a high reaction time

81Views9Replies

exactly what my title says its going to be about average human weight and it needs to have a high reaction time

## Discussions

2 years ago

time distance mass

one horsepower is 550 foot pounds or 746 watts.

Answer 2 years ago

i think im using the calculator wrong its saying 1.62e+8 mAh that seems like alot

Answer 2 years ago

Your going to be in the range of several amps possibly a lot depending on what you mean by fast reactions.

As a passing thought your also going to need very deep pockets because this is going to be expensive.

Answer 2 years ago

is that multiply time xdistance x mass?

Answer 2 years ago

One horse power is 550 foot pounds per

second or 745.7 watts

So you move 550 pounds 1 foot in 1

second, or 1 pound 550 feet in 1 second equals 745.7 watts.

So it is mass times distance divided by

seconds.

If you move 10 pounds 3 feet in 30

seconds that is 10 x 3 / 30 = 1 foot pound per second.

1 foot pound per second = 745.7 watts /

550 foot pounds = 1.36 watts

2 years ago

It seems to me that you are slightly over your limits with this robot project....

Answer 2 years ago

It took you

a lotof time to figure that out right? :)2 years ago

Your going to be looking at several amps at least as a ball park figure.Put a human on a bike and you can go at 15 to 20 MPH with around 746 watts.

However expending the same energy on foot will only let you go at a few miles an hour assuming your not Usain bolt.

Assume your mechanical man is not as efficient.

So Amps x Volts = Watts Knowing your power supply you can calculate an approximation of your current.

2 years ago

Consider that the power input to a physical system must be greater than or equal to its power output (on average, because of conservation of energy), and you can find approximate numbers for mechanical, human output power.

Or rather,

Ican find these numbers, with some help from Google(r). I asked the Google(r) to see what it could find on the topic of, "biomechanics human output power", and one of the links it returned,http://www.sfu.ca/~leyland/Kin201%20Files/11%20Hum...

This document is a slideshow converted to a pdf. At around the fifth slide, there is a table titled "Human Power Output Intensity", and it has for rows, each denoting a different type of activity, mechanical power output for this activity, and "time to exhaustion".

I am guessing these numbers, are sort of an upper limit, for human physical exertion. I know I couldn't power a bike at 20 miles per hour for two hours. I'm guessing that number might apply to Lance Armstrong though.

https://en.wikipedia.org/wiki/Lance_Armstrong

Anyway, you see from that table, that a professional athlete is capable of power output in the range of around 200 W, for a couple hours for activity like bike riding, but capable of much greater power output, around 1 KW or so, in short-timed bursts for activities like power lifting or sprinting.

So, you know, if you want your droid to be brawny, like American Gladiators(r),

https://en.wikipedia.org/wiki/American_Gladiators

I think you're going to need comparable, mechanical output power levels.

(Heh. A.G. Anyone else here who remembers that TV show? )

The good news is electric motors are much more efficient than muscles. I think a typical number for electric motor efficiency is around 80 to 90 percent.

In contrast, human muscles seem to be only around 20 percent, and that number is just based on that same table I mentioned previously. The column labeled "Metabolic power(watts)" is essentially input power, and the column labeled "Mechanical power(watts)" is essentially output power.

So, yeah. That's my guess for the power requirements for your droid, circa 250 watts continuous for a few hours, but also capable of bursts of around 1250 watts, for several seconds.