Angle measurement for balancing robot.

[Luciano]

Hi,

See the PDF file below.

Adjustable weight position, shock resistant.

Swiss Made! (This is a special note for Alain).

PDF doc:
http://leiwww.epfl.ch/publications/g...fer_mic_01.pdf

See the movies:
http://leiwww.epfl.ch/joe/

Best regards,

Luciano

[HenrikOlsson]

Hi Luciano,
Yep, seen that one before too, very cool and seems to work extremely well. The problem again is that the math described in that pdf is so over my head that I can't even begin to understand it. I was hoping that someone (with enough math skills) already had wrote a routine or ported one of the available routines to PBP.

Thanks!
/Henrik Olsson.

[Ioannis]

Just out of curiosity...
How will the robot rise if it is in a initial horizontal position? Alone I think, will not!

Anyway, JOE is very impressive!

The PBP in my opinion is a little slow for the required math.

Ioannis

[sayzer]

Just out of curiosity...
How will the robot rise if it is in a initial horizontal position? Alone I think, will not!
....

A second one will help it to stand up of course!
Like a for loop.

IF the second one is also at initial position THEN NEXT.

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[Ioannis]

Aha! Good idea Sayzer!

Ioannis

[HenrikOlsson]

Ioannis,
I don't think Joe can stand from a horisontal position on it's own. If I ever get mine to work it will hopefully be something like this one:

http://www-robotics.cs.umass.edu/Res...uBot/uBot.html

In one of the videos they show how it recovers from its "resting" position. Very cool and stable two wheeler.

The math seems to range from rather complicated to extremly complicated. Since my mathskills are rather (very, in this case) limited I'm aming for complicated at the most. I'm confident it CAN be done with PBP i just have to understand HOW it works.

I have quadrature encoders mounted on the wheels and I'm thinking I can calculate the robots acceleration by comparing current speed with previous speed and subtract that from the acceleromter reading ending up with 'pure' tilt. My concern now is that the resolution of the encoders are to low. But hopefully I'll be able to understand this Kalman thing any year now..... ;-/

Atleast it's a fun project :-)

/Henrik Olsson.

[ronf]

I don't know if anyone has investigated this one
http://www.circuit-ed.com/accel.htm
Might be worth a try for the angle part and not toooo much $.

[vacpress]

soo..from reading the nuts n volts article, i think the PBP is fast enough. After all, PBP gets compled into ASM, even bloated ASM will run pretty well at 40mhz with only a few tasks, right? this is the advantage of picbasic over parallax..

the nuts n volts december 2006 article pretty much spells it out.. in c though.. they use a RTOS as well.. real time operating system.. this is a type of OS with direct control of hardware. windows is not RTOS, linux is, for example..

the october 2006 article, which i cannot find covers the math, probably in pretty easy to understand terms.. i suggest you look for that... otherwise why not teach yourself the mathematics you need? how hard can it be? brak it into bits... find the main equation and do your best to understand it, then look at some code... the code will look much different...

ive never tried this type of project, but there are a ton of resources.. i watched a video of some really stable 2-wheelers.. off roading, over curbs, etc... also a relaly cute one that could follow children wearing red and had very compelling movement characteristics due to the PID correction being a bit coarse... it dipped and swayed with the child...





anyways... they list these resources:

www.geology.csmu.edu/~dpa-www/robo/nbot

http://autopilot.sourceforge.net/gallery.html

barello.net/Robots/gyrobot/index.htm

jormundgand.net/projects/crunch/

sparfkun.com

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