Biped Scout (Iron Vulture)

Hey…

Are those brackets from a hexapod model… ?

By the way, the video you requested is online youtube.com/watch?v=CizhMaYkU1g

What do you think… ?? it can walk faster if I just push the timing settings a little further… :slight_smile:

nice vid. the gait works really well. the robots right ankle drops when half way thought step. was this intentional. its really good. well done. did you do it using sequencer?

yes the brackets are from my hexapod. :laughing:

thanks. the program is a 3d modeling program called POSER7 its not a cad program but it does open up .obj files…

again thank you for your feedback.

For the less costly conversion for the scout i wish to purpose this idea:
http://i531.photobucket.com/albums/dd355/innerbreed/scoutfoot3.jpg

Pssst!

lynxmotion.com/Product.aspx? … egoryID=87

?
im just simply showing a configuration using the offset brackets.
yeah i realised you also have this in an .obj file, but just didnt download it. you get the idea, and we all know whats ment to be there.

anyway pointing that out has made me realize i meant to put it like this,** in full**
http://i531.photobucket.com/albums/dd355/innerbreed/scoutfoot3-2.jpg

this is the config ill use for this project.

OK hit one problem.

Jim i can confirm that the 645’s wont handle a walking gait “even with 5DoF”!
the ankle rotate servo struggles to keep the weight over while stepping.

lifting the leg is ok and swaying side to side works well. but no Go!

fortunately i haven’t burned out any servos but im curious to have a peek inside. :neutral_face:
I think an upgrade will be needed! :blush: :cry:

Hey Jonny…

I’m about to buy some stronger servos… Do you have any idea of where the weakest links are on the Scout… ?? And how many stronger servos i will be needing… ?

I tried supplying 2S lipo power to one of my spare Power HD 1201MG servo… :smiley: it worked 10sec… :laughing: 8) Dead meat after that… :mrgreen:

it become obvious that once the cog has moved it will take its tole on the appending servo, but say it the scout is in a half crouched position the mail servos that will struggle are the **Knee **and Ankle. the more upright the scout the better the more forgiving it is. but then with this, it becomes top heavy!

so the lower servos of the leg will have to work the hardest.
The ankle rotate and **hip rotate **servos also work very hard while walking, having to hold the body over the center of the foot. you have to get the COG perfect otherwise it will fail the servo. especially in the ankle rotate.

you did a good job in mounting the SSC lower down and not entirely lifting the foot during step sequence was a good idea.
i configured mine for 5DOF and still the **Knee **and Ankle struggled. :open_mouth: :cry:

hope this helps.

Hmm okay… I will change all the 12 servos to 17kg/cm strength then… Hope to receive them in the middle of next week or so…

Have a nice weekend…! :slight_smile:

To give a better idea of the kind of torque at some of the joints, imagine sticking a pencil through the center of the bracket where the servo shaft would normally be for the ankle servo, as an example, and then imagine trying to hold the entire weight of the bot with the center of gravity off to either side of the pencil. It would be difficult to hold that position steady. Strong servos should be used at joints with the highest COG offset.

Hex bots can get away with weaker servos because there are six legs holding the bot instead of only two. With bipeds, when taking a step, you now only have ONE leg holding the bot vs. 3 legs on a hex, assuming a tripod gate is used.

12? take it you going for 6DOF. thought you would only need 10. “5DOF”?

just another thought that could save you some money… you wouldnt need to replace them all.
i would think you would only need to replace the **red **ones:

In order from top to bottom.
Servo joints for 6dof
hipR
hipS
hip
knee
ankle
ankleR

Servo joints for 5dof
**hipR
hipS
hip
ankle
ankleR **

i hope to get it walking with 6dof as it is constructed that way :slight_smile:

good for you. cant wait to see it at its best. your making good progress and i think 6dof looks much better structure wise.

i hope things work out the way you want. unfortunately i cannot upgrade the torque on mine but i will try to help you if you wish.

good luck.

thanks :slight_smile: i’ll post a video as soon as it walks like it’s supose :slight_smile:

i hope to see yours walking soon with 5dof then :slight_smile:

good luck mate !

unfortunately the 645s wont allow this!

anyway if anyone wishes to adopted any of the leg designs please do. i would like to see how they work.
here is another one:

i believe that with the knee doubled up it should make it stronger as each servo wouldn’t have to move as far!
http://i531.photobucket.com/albums/dd355/innerbreed/new2.jpghttp://i531.photobucket.com/albums/dd355/innerbreed/new1.jpg

also adaptions for 5-4 dof.
http://i531.photobucket.com/albums/dd355/innerbreed/scout5dof.jpghttp://i531.photobucket.com/albums/dd355/innerbreed/scout4dof.jpg
for the 4dof the leg would still have to support the weight and carry the COG over, but without the ankle and hip “sway” servos, it cant work like the others. so in order to do this it would need to some kind of “pendulum” effect torso seen in many bipeds.

just ideas!

Inerbreed: All interesting leg gaits and configarations and would like to see these and see how they go for u, i will however stick to the 6DOF as it looks great and would also be great to get it walking. But good thinking on your designs. It is a pity that one cannot move the servos in a walking position and the feedback generated from the pulse wire fed back to create code for that walking sequence. but just dreaming here lol.

this project may also hold your attention.

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