Author Topic: balancing a tall bot issues  (Read 3405 times)

Newman

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balancing a tall bot issues
« on: July 17, 2014, 08:58:12 PM »
Hello,
first i want to thank everyone who made this project and the community behind it. I just got my board, and am trying to make a tall 71cm (28") here is the parts i have:

-3d printed 130mm x 6mm wheels
-2 x GB37Y3530 encoded motors
-Latest Balanduino Board with latest Firmware
-umbilical cord

my issue is it balance for 2 to 4 secs and then when it tries to correct it self it shoots off long distances, i am using the default values, although i trying custom values but with no luck.

am not sure whats the problem yet
is it the structure ? (i put about 1kg on top of the structure and it managed to calm it down)
can anyone suggest any ideas please ?




Jimmy

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Re: balancing a tall bot issues
« Reply #1 on: July 17, 2014, 10:03:41 PM »
@Newman, You might want to read this post... It might help!

http://forum.balanduino.net/index.php?topic=31.0

Jimmy
« Last Edit: July 17, 2014, 10:18:27 PM by Jimmy »

Newman

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Re: balancing a tall bot issues
« Reply #2 on: July 18, 2014, 10:37:41 AM »
Hi @jimmy,

i did take a look at it but nothing helped yet... lets hope someone in the community have some input regarding the stability and pid values. i checked every discussion in this forum but nothing so, far. :(

Jimmy

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Re: balancing a tall bot issues
« Reply #3 on: July 18, 2014, 05:37:44 PM »
@Newman, you should post a video of your robot so members or Lauszus (Balanduino creator) can see what the robot is doing, it is much easier for them see what's going on or maybe make a shorter structure and test it out?
That was what happened to mine and Lauszus helped solve my problem.

Jimmy 

Newman

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Re: balancing a tall bot issues
« Reply #4 on: July 18, 2014, 05:47:32 PM »
Hi @jimmy,
thanks for the reply... i will post a video in the next 3 hours. as for the structure 2 days back i had it on a smaller structure and it was fine but  my aim is to build a 70cm to 1 meter balancing robot just because it has more personality and more room to place batteries, sensors...

today i reduced about 20cm from its overall height it did not effect the stability yet. I found a good PID video on youtube: for future community members who are trying to get the basics of PID and what each value represents.

Cheers.

Jimmy

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Re: balancing a tall bot issues
« Reply #5 on: July 18, 2014, 06:18:58 PM »
@Newman, so the smaller structure worked, the Balanduino was designed to have some weight on the top. Hope Lauszus can help!

Jimmy

Newman

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Re: balancing a tall bot issues
« Reply #6 on: July 18, 2014, 07:52:07 PM »
hi, this is a video of the bot overshooting

Lauszus

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Re: balancing a tall bot issues
« Reply #7 on: July 19, 2014, 01:01:42 AM »
Hi Newman,

Sorry for the late reply.

Please read my comment here: http://forum.balanduino.net/index.php?topic=31.msg174#msg174 on how to tune the PID  values and encoder values. Simply increase P until it starts oscillating, then turn it a bit down until it stops, then increase I until it starts to oscillate and turn it a bit down. Then finally increase D to dampen the robot a little.

It might be easier if you disabled all the encoder stuff in here: https://github.com/TKJElectronics/Balanduino/blob/master/Firmware/Balanduino/Motor.ino. Then tune the PID values until it is stable. After that you will have to tune the encoder values in order for it to stay in the same place.

But I am actually unsure if you will be able to make it balance very good, as the motors might be too weak for such a tall robot. What motors are you using?

Regards
Lauszus

Newman

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Re: balancing a tall bot issues
« Reply #8 on: July 19, 2014, 01:09:55 AM »
Hi @Lauszus
Thank you for your reply i will follow the links you sent and tune it again, the motors are GB37Y3530 http://www.dfrobot.com/index.php?route=product/product&product_id=633

Gear ratio: 131:1
Free-run speed @ 12V: 83 rpm
Free-run current @ 12V: 0.4A
Rated torque @ 12V: 3 kg*cm
Encoder Resolution: 16CPR(motor shaft)/2096CPR(gearbox shaft)
Weight: 205g

Thanks

Lauszus

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Re: balancing a tall bot issues
« Reply #9 on: July 19, 2014, 01:20:53 AM »
Okay fine. The torque seems a bit week in my opinion. Maybe try something like these: http://www.pololu.com/product/1447 if it doesn't work.

You might also try to add some kind of rubber or similar to the feels, so they doesn't slip on the surface.

Regards
Lauszus

Newman

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Re: balancing a tall bot issues
« Reply #10 on: July 21, 2014, 11:59:12 AM »
Thanks for the great help, i ordered rubber tyres and some motors. I will update you guys on my progress as soon as i have some.

Thank you!!

Lauszus

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Re: balancing a tall bot issues
« Reply #11 on: July 22, 2014, 04:46:39 AM »
You are welcome! Looking forward to see what you come up with ;)

Regards
Lauszus