After a few nights of working my way though code and researching ways of motion for the scout, i have almost got it up and running. (its standing and couching at the moment). still a way to go but for now here are some pictures of it sitting under its own weight.
Hardware setup: ABB2 with ATOM 28 Pro, SSC32 V2, PS2 remote
**It currently runs on **
12x HS-645MG servos for the legs,
1x HS-475HB servo for the tilt,
1x HS-225BB mini servo for pan.
iv seen that most bipedal applications are only using the SSC and sequencer software.
and seeing that i have ABBII from an older project i thought it might be as well to use it here.
iv not seen many biped scouts walking but im hoping now im taking this approach, it will open doors quicker.
at the moment im using simple servo commands to control it and hopefully get full control working in the future. and i believe using the Atom pro/Botboard/SSC is the way forward.
I also want to share a propper gait to the sequencer software when i have it done…
I have had some major problems with my scout, most because i’m a cheap bastard and wouldn’t spend the $$ on Hitec servo’s, so i went with a servo called Power HD 1201MG… The only problem here, is that its 1-2mm larger on each side, so it doesn’t fit the SES brackets, and the needed to be modified a little with a bend here and there, but i got it to fit…
yeah it would be real nice to actually get the scout working as intended. with nice gaits and control over the whole project thing would be moving forward for the scout… no pun intended there!
be good to see your progress, maybe you can start a thread.
fortunately i had the servos from other projects from over the years so just get what you need bit by bit and eventually you’ll get there.
i would like to upgrade these servos more as they aren’t perfect. but again money is tight.
Two comments. The rubber feet can be helpful, but they can also be trouble. It depends on how the bot is being instructed to move about. If you have ever tried bowling, it’s easier if your feet slide a bit. We have used felt tabs, rubber bumpers and nothing at all on the bottoms of the feet.
I’m interested in seeing how the analog 645’s hold out for you. We’ve only used the 5645’s for this bot. Good luck!
yes this did pass my mind. at the moment iv not made a step “walked” at the moment im working on rising/lowering the body leaning side to side and front and back. i keep testing different and better ways to do this so apart from the pain staking method of manually moving the servos im coming up with other ideas, so work is slow.
i will see how the rubber blobs effect it once i start walking.
the 645’s seem to be ok at the moment, the knee servo is taking most of the strain. and im expecting the ankle servos to do the same once i initiate a walk sequence.
i may either remove the knee servo or upgrade them.
when suspending the legs off the ground the letting the servos hold their TRUE position and then getting it to stand under its own weight there is a decrease in height by about 20mm. i know that servos do have a bit of play in both their gears and servo horn to shaft. but i also know this is down to the holding torque.!
If you do some simple math in your program it could be possible to use angles instead of actual servo positions. Then you could easily swap left and right positions. It could make controlling it a bit easier.
Iv been thinking about redesigning the knee section for something that will, Take the weight down, be more forgiving on the servos, and make writing code easier.
**
here is an idea i have in mind:** http://i531.photobucket.com/albums/dd355/innerbreed/scoutfoot.jpg
im still trying to keep the bent knee effect as its… Well… its cool. 8)
the only problem im thinking with this design is that the body cannot rest on the feet if power out.?
Also to take the weight down i have removed the HS-475HB servo and put another HS-225BB mini servo in its place. i have used smaller hex standoffs but iv had to add some washers to make up the extra space. http://i531.photobucket.com/albums/dd355/innerbreed/100_1949.jpg
How are your progress with the walking for now… ?? I have alot of problems with my servos… they are to weak…
They should be able to pull 13kg/cm at 6v, but I don’t trust that very much at the moment…
I have been thinking of buying some of these servo’s… they pull 16kg/cm and they are digital instead…
iv not attempted walking yet. but i am also trying to work on the realtime code at the same time. I need help with programming the Gait and IK equations. i cannot find any info on 6dof equations!
i havent yet ordered the parts for the redesign yet as im looking for feedback before i spend.
you must start a thead, would be interesting to see what you have. and to see your progress.
have you started programming yet?
What do you think of my scout… ?? 8) i actually just modified it in the last 1 hour… It’s now 5DOF and walks now…
The 5DOF setup looks a little like the idea you had earlier on the drawing board, so i can say that it works…!! Thinking of buying those parts you used on the model…
Much lighter for my servos to manage also…!!
You can find the pictures of the 5DOF Scout on my tread…
sounds nice…!
