My first robot : a quadruped with 3 DOF by leg

It just trying to walk correctly for the moment :)

Update 2 : new video of the "spider style" walk

Hi everybody my name is MoX First i want to say sorry for my english : I'm French ...(and sorry for my president too...lol)

So this is my first robot, a quadruped with 12 standard servomotors and 3 dof by leg.

I make all the part myself with aluminum plate.

For now, it's just control by my computer link to it with a RS232 connection, and a SSC32 controlling servomotor card by Lynxmotion (a real good card i think :)

Today I'm trying to control it with an Arduino car but the com with UART between the two cards is not operational for the moment :( I'm also trying to include a URM37 ultrasound sensor :)

The first step was to create a second axis for all servos.

I used some support of roller-blade ball-bearing, and I stuck it to the servo with cyanoacrylate adhesive :

Now , let's use my best enemies (which offer me a lot of blister ! ) :  Saw, file, and tech vice (lol not the same signification in French MDR)

The body :  PVC plate (dimensions 180x180mm,5mm of thickness) :

Now the legs : I am going to use the terms of "shoulder", "leg" and "scratch" for the 3 parts of the legs... (sorry I know that my english vocabulary have to increase .....)

All the aluminum parts are from an old 19" computers rack ( 2mm of thickness )

First type of servos support : for the 2 servos of the "shoulder"

I have fold the plate following the dotted line, using a tech vice :

It's very important to align correctly the axis of the servo with it's new axis (the bearing part)  and to follow this alignment with the aluminum support of servomotor. Personally it's not perfect (i wish i had a numeric CNC :) future project ?!

when you love, you don't count (French proverb)...so 3 more to make ... or you could count your blisters LOL : 600W blister by hand !! thank you Miss metal file ! ........ heuuuu if you don't understand the blister thing....just French technical joke LOL

And the result with servos , but not yet fix to them ( one of them is on the "leg")

The result with the 4 supports of "shoulders":

 

Now the support for the "leg" : more simple than the other LOL ...... but... but ...it's just a poor piece of aluminum ?? ... YES o_O

The leg:

The result with 4 legs :

Now my favorite part : the scratch:

Same idea : Saw, file, and tech vice ...and blisters !

Result :

ET VOILA !

 

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Rhaaa it's exactly what I'm thinking !!

When I program the second way to walk, my poor robot cry a lot and beseech me to not make him so mechanical (He was very bored to walk that way ..... like a poor military boy LOL)

My goal is to make it more alive , more suspecious, more ...the way you think ! (good point of view ;)

So I'm alway working on a walk that could respect my goal !

Have fun with your robot ...and the rest !

MoX

This is absolutely stunning craftsmanship and the movement seems perfect. If I ever build a walker it would be around this type of setup.

Hi Geir :)

I really appreciate your comment !! thank you very much (it was the first time someone say that my work is stunning craftsmanship (I live in the country where people prefers their cows LOL) ...and i must look in a dictionary for that compliment LOL :) !

But like all artist I think that this walk could be improve a lot ;) (indeed after some steps, there is a trouble with one leg and my poor robot fall like a cyber drunk LOL)!

I'm working on a different walk just now (and I'm really proud of this one).... I'll post it soon (I' m drinking  coffee since 3 hours so I think that this night will be productive :)

When the walk will be "perfect" I think that I could post the code ! I'm using a SSC32 servo-control card witch need just some positions like #0 P1500 S300 (#0-->n° servo /  P1500--> position  / S300--> speed) but my goal is to send those position with a Arduino and a UART connection ...so everybody could use my position and repeat the walk !

Have fun with your projects :) ! And thanks again for that comment ! It motivated me to drink an other coffee and improve my robot walk !!

MoX

Hi everybody !

I post a new video of my quadruped robot :)

Sorry for the bad quality, it was taken with a cheap web-cam ......

The walk is not very good but the advantage of this video is to show the average consuming of the 12 Hitec Servomotors !

I'm working on a better walk !

Have fun with your projects !

MoX

In fact , watching this video for the second time, I'm asking myself if the walk is not worst than the first version :) LOL

Give me your opinion !

I think that a small sleep could be good for me LOL !

I'll work hard and post new video soon !!

MoX

I like the robot. It makes me want to build a walker myself.

However, in my case, that will have to wait, as I am still knee-deep in my "Shrodinger" project and probably will be for some time yet.

Hi Dan M

I'm really happy to know that my humble robot gives you some motivation for walking robot :) I think that it's a very interesting type of robot !

Now I'm like you and don't have enough time , indeed I work on a second robot (a biped with linear home made actuator with servomotor :) and my poor quadruped doesn't evolve a lot ;)

But i bought 12 Futaba S3003 servomotors (a little more powerful than those i used for my quadruped (3,6Kg.cm --> 4,1kg.cm at 6V) and all the comments on that wonderful website, motivates me to finish my quadruped !

Good luck with your Shrodinger project, a very good work furthermore :)

MoX

Thank you. Good luck with your projects too.

I have been thinking my next project would be a monkey-like quadruped/biped.  In other words, like a monkey, it can move on all four legs, but also can stand on it rear legs only. If I can make it right, I would cover it with fake fur and make it child-friendly.

This is a very good and funny idea !!

Walking on four legs and also standing on rear legs will be a real challenge ! I'm waiting for your creation !

Have a good day

MoX

Thanks again. Yes, it will take some thought, but I have a lot yet to do on Shrödinger, so that will give me extra time to plan ahead to that next robot idea.

 

I like the idea of it standing on rear legs and holding up its arms /(front legs) to give a hug to children. I will need extra degrees of freedom, at least in the front limbs, and probably need to use servo-savers to allow for slippage when being handled by children.