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Help on traction for a biped

I am currently working on what is my second robot project.  It is a simple biped.  It relies heavily on balancing itself on one foot for walking.  The feet are cut sheets of PVC and are giving me some slipping when it walks.  I was wondering if anyone had some suggestions for something to give it a little more traction when it walks but with out making it too sticky.  I am hoping to have some more details and pictures or video up next week if anyone needs more information.  Thanks.

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So I have tried almost all the suggestion listed in here but i have had no luck.  Any amount of traction I added would just trip the robot and it would face plant.  However I took someones suggestion to move the center of gravity by putting the feet closer together.  that has worked for the most part and it is now walking forward not perfectly but as good as i can hope for at the moment.  I am now working with turning and i am having the same slippage issue again.  Now the only thing i can think of is perhaps there is a way to make the servos not jerk so hard when they turn.  I was wondering if this is possible though programming or do i have to modify my hardware.  I would prefer programming since that just takes work and not money (working on a budget).  Here is the link for the project http://letsmakerobots.com/node/31214 if someone would like to see what I have so far.  Thanks

by breaking up the whole move into smaller parts and adding delays between the smaller moves.

my $.02 anyway. I think Ro-Bot-X mentioned something similar.

I think that the rubber liner used in drawers would really help your robot gain some traction. Here's a link to show you what I'm taking about. http://www.nextag.com/non-slip-drawer-liner/shop-html You could cut these sheets up to fit it wherever you need it. Hope this helps!

I have seen those at the dollar store i will have to go grab me one.  Thanks.

Alright I just added my project page up on here with two videos.  Let me know what you think I could do better or if there is a glaring issue that i just dont see.  Thanks

My experience tells me that you have a timing / balance issue, if you need to make the feet stick. I'd look into that instead. It's perfectly doable to make a fast biped, with very slick "feet", as long as balance and timing is there.

Great suggestions I will give them a shot when i get home from work.  My digital camera should be coming in the mail today so I will get some pictures and videos up and online.  As for adding a gyro I am very new to making robots and have limited experiance with electrontics so that seems deep and complex to me.  I am using this as a baby step into robotics and am trying to more or less learn through trail and error (my only other robot was the Start Here LMR kit from solarbotics).  I will post more and look forward to your feed back.  Thanks.

I agree with the others about gluing on rubber pieces to give traction. If he drags his feet, then the friction will be too much, so I would also advise to have the robot raise its foot straight up before moving it forward. (knee action).

As to the balance problem, there are a couple solutions. One would be to make the feet large enough to give it a good base to stand on and another would be to use a gyro so it can't tip over.  Another key to not falling is just like in humans, to allow it to have lateral movement at hip or ankle, so it can shift its balance over the foot that is holding it up. Then the other foot can be raised and moved all around without losing balance.

If you are looking for a rubbery foot piece, how about cutting a slice off an "art" eraser? -(the big square or rectangular ones.)

 

Maybe a rubber band around the outside of the foot will touch a bit the floor so that way you have some friction but not too much.

hot glue? rubber cement? Back in the day they used to sell rubber mats that one used for friction to remove lids. I haven't seen those around for years though.