Society of Robots - Robot Forum

General Misc => Misc => Topic started by: mackmelby on February 01, 2008, 10:10:19 PM

Title: Need advice on Balance-bot desing
Post by: mackmelby on February 01, 2008, 10:10:19 PM
Im looking for the most cheap, simple, inexpensive way of building a balance bot. I'm thinking of using a ground sensor "cane" or attaching a slide-potentiometer to a hanging weight...may be a bit unstable...but i can always make the bot taller or more top heavy...so far, I have purchased two 100rpm 14 oz-in motors with 2in wheels and a speed controller. Robot does not need to turn, only forward-backwards balancing. ANY ADVICE WOULD BE APPRECIATED
Title: Re: Need advice on Balance-bot desing
Post by: SmAsH on February 01, 2008, 10:14:26 PM
please explain more about what you want...what is your budget? what is your experience? do you have the right tools/equiptment?
Title: Re: Need advice on Balance-bot desing
Post by: HDL_CinC_Dragon on February 01, 2008, 10:36:32 PM
And what is the final goal you hope to achieve?
Title: Re: Need advice on Balance-bot desing
Post by: frank26080115 on February 01, 2008, 11:20:53 PM
my idea involves a sharp IR range finder, a microcontroller with PWM and ADC, and a motor with driver

do some research on how the range finder works, how to use ADC on a microcontroller, how to use PWM on a microcontroller, all of these are on this site
Title: Re: Need advice on Balance-bot desing
Post by: SmAsH on February 01, 2008, 11:30:08 PM
lol the goal is probibly only to make the robot stand up and balance lol hdl_cinc_dragon ;D
Title: Re: Need advice on Balance-bot desing
Post by: HDL_CinC_Dragon on February 01, 2008, 11:43:44 PM
lol the goal is probibly only to make the robot stand up and balance lol hdl_cinc_dragon ;D
well duh lol, but I mean is their a greater objective? Perhaps a specific circumstance?
Title: Re: Need advice on Balance-bot desing
Post by: SmAsH on February 01, 2008, 11:50:45 PM
oh what to like move to a place or sence something?
Title: Re: Need advice on Balance-bot desing
Post by: HDL_CinC_Dragon on February 02, 2008, 02:11:13 PM
basically


So how 'bout it Mack? We need a little bit more information to help you out properly :)
Title: Re: Need advice on Balance-bot desing
Post by: SmAsH on February 02, 2008, 03:57:31 PM
well the first thing we need to know is your budget. if your a beginner and have only made one or two robots expect to spend $100 upwards. lol. second thing: your design you want/goals to achive. third please show us a layout. like design of it. fourth...sorry normally i can only count to four :-[
edit: heres a quick cad i did a model i recently saw on the web. (and the downloadable cad for people with google sketchup)
Title: Re: Need advice on Balance-bot desing
Post by: Rebelgium on February 02, 2008, 06:01:02 PM
Also search the forum and the web to look for inspiration.
The robot smash drew is also in the video forum on SoR.
Title: Re: Need advice on Balance-bot desing
Post by: SmAsH on February 02, 2008, 06:14:12 PM
yes! thats it! i've been wondering where ive seen it before. ya http://www.societyofrobots.com/robotforum/index.php?topic=2543.0
Title: Re: Need advice on Balance-bot desing
Post by: mackmelby on February 07, 2008, 01:44:08 PM
Ok...I don't have an extremely limited budget...maybe $300 + parts that I already have, ...the balance-bot only needs to stand up straight and also needs very quick response. The big limitation here is that I suck at programing/electronic stuff (only because I end up frying expensive equipment) So my plan is simple,the robot will be controlled by one main sensor, probably a potentiometer hooked to something that changes when robot tips, like a hanging weight or a stick that drags on the ground. I was wondering if there was a more accurate way of measuring gravity or tilt without getting into too much programing. I'm doubting that the hanging weight is gong to work very well so tell me what you think. (Ill try to post some cad drawings soon)
 
Title: Re: Need advice on Balance-bot desing
Post by: mackmelby on February 07, 2008, 02:34:48 PM
Ok, ill Let you guys in on what I'm really building...But for now, I have to work on the prototype that operates on two wheels;)
Title: Re: Need advice on Balance-bot desing
Post by: mackmelby on February 07, 2008, 08:56:51 PM
Also...sorry for the late response...Im used to forums that take weeks to respond..lol JK
Title: Re: Need advice on Balance-bot desing
Post by: bukowski on February 08, 2008, 11:16:40 AM
That is an ambitious project, and something I (and probably a whole lot of other people) have thought about. First off, I think your Pot idea wont give you ideal results, especially if you add in another axis. You would do much better with a set of MEMS rate gyros and accelerometers, and they are getting very affordable if you cant scavenge the parts. Keep us updated though, it looks interesting!
Title: Re: Need advice on Balance-bot desing
Post by: mackmelby on February 08, 2008, 09:28:38 PM
Ok...so, If Im going to experiment with gyros+accelerometers, what kind of microcontroller(s) should I use (where to buy) If I have never programed a microcontroller before? ...I think the biggest thing i have ever programed was a screen saver that popped up random letters all over the screen... lol :D..So Im wondering if I have the skills to tackle this project(I think i do as long as i dont end up frying anything) any suggestions on gyros, accelerometers and motor-drivers and where to get them would be helpful. Also need to be done by less than a month lol so ill be working hard and fast.
Title: Re: Need advice on Balance-bot desing
Post by: TrickyNekro on February 09, 2008, 03:46:28 PM
A friend of mine got a nice balancing robot with just some reflect sensors!!!
Code is the problem...
And try to place heavy objects like batteries was low as possible...
Less dynamic energy in your robot means easier balancing!!!

Cheers, Lefteris
Title: Re: Need advice on Balance-bot desing
Post by: Trumpkin on February 09, 2008, 03:48:28 PM
you could also use Sharp IR pointed at the ground to detect your tilt.
Title: Re: Need advice on Balance-bot desing
Post by: mackmelby on February 09, 2008, 05:33:30 PM
TrickyNekro : I think I'm going to run some dynamics tests before I build the chassis because for one thing, I read all sorts of opinions about what people think the weight distribution should be and everyone seems to have their own opinion. Also it's a science fair project, any extra data is helpful. So maybe Ill post the results of my dynamics test if your interested.
Title: Re: Need advice on Balance-bot desing
Post by: Rambo on February 13, 2008, 04:33:14 PM
Hey, i'm thinking about building a balance bot with Sharp IR sensors to detect tilt and stumbled across this forum whilst doing a bit of research. Has anybody tried building a bot with IR sensors or is a gyro and accelerometer combo the best way to go.

How are the tests going mackmelby ;)
Title: Re: Need advice on Balance-bot desing
Post by: mackmelby on February 15, 2008, 09:39:35 PM
Well...Im sure an IR sensor would be good for a smaller scale balance-bot, but idk..If you want an example of a simple IR balance-bot, type "Equibot" in youtube or Google...I think the equibot is documented somewhere (it's not hard to find, just search google) And as for the dynamics tests...Adding weight to the top of robot causes robot to fall slower. If you want a simple way of proving it for yourself, just take a broom and balance it with heavy end up...easy...and then try heavy end down...Its more difficult...Also I found out that your motor speed must be in proportion with the height of your robot.