Let's Make Robots!

My second robotic project : a biped with 10 DOF by leg :)

Hi everybody :) This is my second robotic project : a biped with 10 DOF by leg, build with home made linear actuators with standard servomotors.

This is how i built my linear actuators :

First I found some copper tubes, and a M4 fixing-plate :

They need to slide perfectly :

then I fixed a 608ZZ (20mm of diameter) ball-bearing to the M4 fixing-plate with some tape (I think i may use some copper string ;)

Next step : I fixed a M4 threated tube with cyanoacrylate glue to the smaller copper tube (the one witch will slide into the bigger one)

The result :

After that, I made a fixation for the servomotor always with fixed with cyanoacrylate glue: :

And I made a support for the entire linear actuator, to simplify the future fixation to the structure :

The result with the servomotor :

The deferents positions :

And I repeated this five times :

Then i created a prototype of knee-cap with a piece of nylon, a door button and a M6 fixing-plate :

I dug a spherics hole with a reamer since almost the half of the height of the door button :

and a small fixation with a spheric hole too :

After that I used some small pulley with ball-bearing :

and split them in two parts (pfiouou quite stuff metal ;), and fixed them to aluminum square :

I used them as fixation for the linear actuators.

Now a smelly realization : PVC folding with my poor cooker ;) for making a support for the linear actuators (but i did not keep this fixation in the prototype as you can see in the next pictures.

It was only the first prototype of shinbone.

and finally built a shinbone prototype with all of that :)

Here the deferents positions of the shinbone :

The right position :

by moving one linear actuator in one sens and the other, in the opposite sens , it could move to the right :

or to the left :

Well now this shinbone need a foot , so I used some pieces of PVC (2mm of thickness) :

and created a foot with an articulation for the front, that will permit to be more smooth (I hope LOL):

The sides :

The top :

The bottom :

The result with a  spring , useful when the robot will rest on it's leg (I hope ;) :

The result with the shinbone :

Now the evolution of the prototype (the linear actuator's fixation changed , I replaced the PVC by aluminum pieces) :

After that i made a knee fixation with a ball-bearing , and the rest of the structure with aluminum square tubes :

I built the hip like the articulation of the shinbone :


The result of my first robotic leg prototype :


Now the big outstanding : did the leg will works ?! o_O ... we are going to see that step by step, with all the programming part :) ...so the Arduino softwarecall me ......

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If I could say "holy shit" in French, I would - just to make sure you understood how cool I think this is!

I really admire the work you've done with the actuators.  I do wonder about the speed of the mechanism though.  Do you think it will work fast enough to give you a smooth gait once you have everything completed?

I'm looking forward to a video of the completed leg assembly.

I must admit that the biggest issue on that project, is the speed of the actuators !!

But like it's 100% salvage material, and standard servomotors, the speed doesn't matter for the moment :)

It will be a Tai-chi biped :) lol

It's just a prototype for the moment, and in the future, i will use DC motors with bridges. But the way to control servomotors modified for 360° rotation, with an Arduino card, is so simple, that I want to try with it for the moment.

I think that I'm going to use some drill motor in the future (I study this solution just now...)

"holy shit" :) thank you very much, I must admit that this project is pretty cool to realize :)

Sarah Conor don't run so fast , I only got one leg LOL

Have fun dude


Yes, we need you to build a tai-chi bot!  There are too many battle-bots and autonomous tanks with gun turrets.  What the world needs is an army of compasion-bots that can lead meditation sessions!  I will nominate you for the Nobel Peace Prize - though the Nobel Committee never returns my phone calls.


I'm totally agree, too much war inspiration robots !

Mine will have a flower in is mouth and will play some Pink Floyd music :)

More seriously I'm very disappointed when I see robots playing violin, dancing, or shooting peoples like a terminator, and on the same time , seeing human peoples in the Fukushima catastrophe, just trying to sprinkling a nuclear central, like if Azimo couldn't hold a fuck**** pipe hose !!!

War is the first way to evolved ....when you see the human evolution ..... it's so disappointing !

The world is what we make with....... so let work together for a better world :)


A new robot already, you're a machine ! ;)

This one looks crazy, great mechanic, ambitious project, I like it !

Good luck with this new one :)

hi dude :)

Lol, I'm not a machine (same if it could be cool ;) but in reality a live in the country (where there is nothing to do...) and I have no girlfriend since some months now LOL so I make robots ...... no in fact the first reason is that I'm in vacation (same if I have to write a rapport for my bachelor degree in industrials network (licence pro en fait...)).

Thanks for the great mechanic :)

I'm agree it's an ambitious project (perhaps too much ...;) but I'm realist and don't try to do the same work as complex bipeds like Azimo or other future Terminators ..... it's just an lod dream of mine and I will see how it could evolve.

have fun dude !


apres plusieur mois  de recherche sur la fabrication des jambes de mon robot enfin je trouve comment je vais realiser mes jambes

j ai un projet de faire un robot de 1.40m de hauteur

je suis sur marseille tous conseilles est bien venu

je vais me servir de ton projet qui je trouve tres bien parmi tous ceux que j ai vu

merci pour la suite et la programmation


Bonjour. Bienvenue à LMR.

Les membres sont ici de partout dans le monde. Toutefois, nous vous demandons de publier en anglais, parce que les indices de site Web en anglais seulement, et bien que pour beaucoup l'anglais est une langue seconde, il est de notre langue la plus commune et partagée.

Pardonnez-moi si mon français est pauvre, je compte sur Google Translate.

[In English]

Hello. Welcome to LMR.

Members here are from all over the world. However, we ask that you post in English, because the website indexes in English only, and although for many English is a second language, it is our most common shared language.

Forgive me if my French is poor, I am relying on Google Translate.