I started over on the legs. Learned some of what not works on the first set. New legs: the black is nylon-X, blue is ABS, gray is aluminum. I bought a Tormach CNC this summer and have been making some parts out of metal. Lots of fun and lots to learn. The gears and shaft couplers came from Serrvo City. I am still using RoboClaw motor controllers. There are 6 motors on each leg. 3 for hips, 1 for knee, and 2 for ankles. For the main support I used 1 inch square alum. (80/20). All parts are in CAD, Autodesk Inventor. Don't have them working right yet. Grog, thanks for the help with the pictures.


5 years 5 months ago

Wow !  Great Design & Post Harland !
How much do they weigh ?
They look really solid.
What is the max angular speed ?

And look at all those nicely formatted pictures !  

Looking very good! Looking forward on watching videos of it doing the shuffle.

Any idea about proximate cost?

And I know they cost a lot but ever thought about linear actuators?

They look great,

It looks like the foot is narrower than you first version.

Can't wait to see them walking



5 years 5 months ago

Not sure how fast, don't have it working, but the new design makes it easer to change the size of the motors. The motors are mounted on the outside. Currently one mega bd. contorls everything and I see delays on reading motor boards and sending the next command. Maybe it should be more like the inmoov body one board for each leg, and MRL does the heavy lifting. I will need several types of sensors to keep it upright, to make decisions on controling the motors. Pressure sensors on the bottom of the feet.

weight of legs and hips 27.5 lbs.  12.5 Kg, used bathroom scale

size & lenghts:
foot (floor to ankle piviot )  5.1 in or 129.5
lower leg   (ankle piviot to knee piviot) 14.3 in. or 363.2mm
upper leg  (knee piviot to hip piviot)  14.7 in. or  373.4 mm
hip  (hip piviot to base for inmoov) 4.3 in or 109.2 mm
so legs from floor  to  inmoov attachment are 38.4 in high or 975.4 mm
width between leg centers  9.97 in or 253.2 mm
width of foot 6 in. or 152.4mm
I thought about linear actuators but like you said expensive. Now thinking about them again, the cost might even out. They provide feedback that can be read by the A/D converter in the Mega bd. So you wouldn't need roboclaw boards to read the read encoders and motors with encoders. Normal DC motor controller are less money if they don't include encoder circuits.
I am working on the costs. In Autodesk Inventor when you model a part you can add a cost and description.
I have been constrating on building and getting the legs to walk and did not put in this info.
I use Simifly3d for printing and it tells you the cost for each part printed and I keep a log of that info. So I am going back and adding the data. When you build an assembly you can add a parts list. The parts list can be exported to a spread sheet to come up with an estimated cost.  I will let you know...
I apprecate the support, interest, and coments. This is turning out to be a lot harder then I thought but still lots of fun.