I’m in the process of building a 6 DoF (per leg) design for use in a class i’m taking and was hoping you guys could give me some input on the SES layout of the design.
I’ll be using 12 5990TG for actuation and 2 lipos for power (they will be placed in the feet hence the space in the picture)
The picture is not complete it is missing 2 small pieces of metal in the hip and ankle that will hold the two stacked servos together. This causes the picture to look slightly odd.
Thanks For the Help!
Keep in mind with such a high CG, stability is going to be a challenge. Does it have to be so tall? is a custom bracket going to be made to attach the ankle bracket to the foot while allowing room for the lipos?
Can you rotate that image so I don’t get a crick in my neck?
I’m going to machine the torso, a flat plate for the hips (which will connect to the 4 ASB-02), something similar for ankle, and a holder for the lipo in each foot.
is the CoG so high that there’s little hope of it standing? The main goal of the project is to get it to balance and react to external impacts/terrain changes so while it would be a lot easier to make it short and low to the ground, im not sure if that would be quite as impressive, tho i don’t wanna make something that’s way too hard to balance in the first place, so i guess what i’m saying is, is it much much too high or just slightly too high? I was kinda hoping the lipos would lower the cog some too, they will be larger 8000mAh packs that weigh over a pound.
Two things…
The best way to make the hip and ankle joints are to use two ASB-04’s. You wouldn’t need to make a special plate and it would simplify the mechanical arrangement.
Tall bipeds usually require a fast method of feedback in order to maintain balance. I’m no expert on that, but I know it’s difficult. The advantage with the SES parts is you can make it as tall as required. 8)
I see, since it’s a balancing project then it would make no sense to have a short configuration. I think you can make it work with the height that you have. I’m not much of an expert either when it comes to dynamic balance control, but with the SES feet, they do a good job of spreading the load so the height you have might be fine for your criteria. If you discover that the height is a little to top heavy, you can always lower the design since the SES brackets are easily swapped out or reconfigured to get the design you’re after.
Interesting project. 
Love those long legs!
Might want to consider “inverted pendulum” algorithms along with the appropriate acceleration sensors to implement your biped.
And a not-so-obvious point, if you do indeed implement inverted pendulum balance algorithms, you’ll find that it’s best to put the weight (i.e. batteries) up high, to allow a faster COG shift.
Alan KM6VV
Thanks for all the info! None of that throws up any red flags as far as working for stock SES pieces? Like nothing looks like it wouldn’t assemble correctly?
The best way to make the hip and ankle joints are to use two ASB-04’s. You wouldn’t need to make a special plate and it would simplify the mechanical arrangement.
Agree 100% - I’m not sure how you intend to attach the SES foot to the ASB11b’s with the lipo packs placed there.
Okay I re-did the model to use ASB-04, the reason it didn’t have them originally is I mistakenly thought that the 5990TG would have the second servo horn for the inline axis included… well now that I have them I can see its not the case so we now have this!
Are you asking if you can mount two ASB-04’s together back to back? We do it on almost everything.
For help with using the 5990 and our brackets you might want to read this post…
