# humanoid legs questions

The following are a couple of basic questions about the legs of a humanoid:
1)How do u calculate the number of degrees of freedom of the leg
2)isn't 3 servos on each leg necessary(1 for knee,1 for stabilization , 1 for thigh) why do a lot of humanoids contain 4 or 5 servos on the legs? what are they used for?
3)I am part of the humanoid team in my college and have been given the task of making the walking algorithm:

what are the steps that I need to take to create such an algorithm.please specify as much necessary steps as possible

help is appreciated

roshan001:
3)I am part of the humanoid team in my college and have been given the task of making the walking algorithm:

Do you have any experience in electronics or even Arduino ?

Did you know that for humonids the average number of legs they have is less than 2 ?

1. Degrees of freedom is a basic concept. If you don't know how to figure that, then you need to do some studying before you go much further. How many places can a leg move? How many directions can in move in each of those places?

2. 1 servo is enough for a knee. But think about a hip for a minute. Stand up and move your hip around, forward and back and then out to the side. How would you do that with only one servo?

3. Sounds like you might be in a little over your head. Time to do some serious study. Not the kind where you ask someone on an internet forum to teach it all to you, but the kind where you do some research and find some articles or books on humanoid robots and do some gasp reading.

srnet:
Did you know that for humanoids the average number of legs they have is less than 2 ?

I don't know. Does a bear walking on 2 legs still have 4 legs?

That reminds me of something I saw on a chemistry blog: "Would the people who like working with this [exceedingly unstable explosive] compound raise their hands? Although I may be assuming too much about the limb-to-chemist ratio."

MorganS:
I don't know. Does a bear walking on 2 legs still have 4 legs?

That reminds me of something I saw on a chemistry blog: "Would the people who like working with this [exceedingly unstable explosive] compound raise their hands? Although I may be assuming too much about the limb-to-chemist ratio."

Well, if you're looking for someone to hire to work with said compound, maybe that's a good way to narrow it down to the best of the bunch. At least you cut out the ones at the bottom.

2 for thigh, it can move forwards and backwards, and open and close your legs (walking/doing splits)
1 for a knee
1 below the knee to do twisting action between lower leg and ankle
1 bend ankle
A whole bunch more in the foot bones

MorganS:
I don't know.

Most humonoids have 2 legs, but a few have only 1, or none.

So the average number of legs for a humonid is less than 2.

Or to put it another way, on average, most humonoids do not have two legs.

srnet:
Most humonoids have 2 legs, but a few have only 1, or none.

So the average number of legs for a humonid is less than 2.

If a crutch counts as human made leg then the number will be greater than 2

for humonids the average number of legs they have is less than 2 ?

Please define "humonids", and post a wiring diagram.

roshan001:
and have been given the task of making the walking algorithm:

I reckon you should start with the simplest possible leg that will allow the device to walk.

If you are talking about a self-balancing 2-legged creature then I suspect you face a very major challenge if you are not already able to answer the questions you have posed to us.

Never mind degrees of freedom and such, do you have any idea how a human's walking motion operates - especially how its centre of gravity is managed. As far as I am aware the only purpose of the legs is to stop the torso from falling on its face. Walking involves more than legs.

...R