RoboSavvy Forum

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2010-05-24T21:01:01+01:00

The strange peak values you describe sound very much like worn out potentiometers in the AX-12 servos. I know these symptoms from heavily used RX-28s, they don't appear with new servos though.

Statistics: Posted by SK — Mon May 24, 2010 9:01 pm

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2010-05-24T11:56:49+01:00

A Robotis calibration tutorial link can be found here :
http://robosavvy.com/forum/viewtopic.php?t=5977

but if your robot doesn't go crazy when you let it on the ground, it won't help you i think.

the problem with AX12 feedback is that you have sometimes strange peak values that comes.
if you have your robot in your hand, this peak value (when it comes) stay for too much time and the program starts to move the legs according this fake value.
that's why the robot can go crazy.

if your robot is let on a plane surface, when this fake peak value comes, the program start to move the legs too, but this feedback value will quickly be replaced by a unnoisy value, and so, the robot won't get crazy.

keep in mind this program was made for fun, it was one of my first.
the more the actuators feedback is perfect, the more program works fine,
but if it is too noisy, you will face such inconvinience as you encountered.

try to enlarge deadzone values in the program.
your robot will be less reactive but it may help to resolve your problem.

in all case, the best way to do such a program really run fine is too use a 2 axis accelerometer in addition with the gyro.
i think i will buy some but i would prefer going with an AX-S20 like sensor.
but for the moment, there is no alternative choice to the robotis AX-S20.
the 6 axis imu from hylands seems not to work fine with cm510 according to some people on this forum.....

EDIT: in order to protect your hardware, you can define limit values for each actuators using roboplus manager.
if you do so, the actuator will go to alarm mode before you break something.
The more i use AX12, the more i think the only reliable feedback value is the temperature

Statistics: Posted by FabinovX — Mon May 24, 2010 11:56 am

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2010-05-22T04:35:12+01:00

Thanks for your help FavinovX, I try to let the robot in the ground ans then run the program, in this point all was fine, when I move the robot to change it position then happens what I wrote before, It sends the two legs and foot to the same side and I need to turn off quicky befofe something bad happens. How can I calibrate my robot?, is correctly builded and if I run the demo program its fine.

Thanks

Carlos

FabinovX wrote:
Maybe, that's due to the noise of AX12 position feedback.
you can try to enlarge dead zone in the soft.
but first you may try this :
Just put the robot on the ground before starting the program.
if it still goes crazy, then you should calibrate your robot.
In effect, if your ax12 can't reach their goal position when standing there will be a difference between goal and present position, so that, the robot will analyse this and move for nothing.

EDIT : the gyro is just use to stabilize when there is quick movements,
it doesn't help when you do slow movements.
it's only AX12 position feedback that helps in this case.
for information, my very first try was based on AX12 torque feedback but it was more noisy than position feedback and the soft was really more complicated and longer because torque value changes according to the rotation direction too.

Hope it will help.

Cheers
FabinovX

Statistics: Posted by cajacava — Sat May 22, 2010 4:35 am

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2010-05-07T20:32:46+01:00

Maybe, that's due to the noise of AX12 position feedback.
you can try to enlarge dead zone in the soft.
but first you may try this :
Just put the robot on the ground before starting the program.
if it still goes crazy, then you should calibrate your robot.
In effect, if your ax12 can't reach their goal position when standing there will be a difference between goal and present position, so that, the robot will analyse this and move for nothing.

EDIT : the gyro is just use to stabilize when there is quick movements,
it doesn't help when you do slow movements.
it's only AX12 position feedback that helps in this case.
for information, my very first try was based on AX12 torque feedback but it was more noisy than position feedback and the soft was really more complicated and longer because torque value changes according to the rotation direction too.

Hope it will help.

Cheers
FabinovX

Statistics: Posted by FabinovX — Fri May 07, 2010 8:32 pm

Is not working

2010-05-05T03:58:58+01:00

Hi, I'm really new in all this. I download the motion and task files from your post in my premium kit but when I run the program the robot send the two legs to the same side or to the front at the same time and I can't controle it. Can you help me please? I'm using the gyro of the kit

Statistics: Posted by cajacava — Wed May 05, 2010 3:58 am

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2010-04-25T20:42:48+01:00

thanks for the code! pretty good stuff

Statistics: Posted by mattman — Sun Apr 25, 2010 8:42 pm

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2010-04-22T21:59:43+01:00

Hi,
the code i gave is a stand alone code.
but if you want, you can copy and paste it to the original code given with with the premium.
to make your robot less jumpy, you can try to modify the dead zone values in the code.
but the bigger are the ranges between negative and positive value, the less reactive is the robot.

see you

Cheers
FabinovX

Statistics: Posted by FabinovX — Thu Apr 22, 2010 9:59 pm

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2010-04-19T03:27:06+01:00

just a question with this code and motion installed can you not use the remote controller to walk anymore? mine stopped working aswell as the demo mode no more works.. thanks talk to you later.

Statistics: Posted by pikaj00 — Mon Apr 19, 2010 3:27 am

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2010-04-18T04:54:10+01:00

tried your code works great thanks alot! mine is a little jumpy when standing still but not to bad.. love it thanks again

Statistics: Posted by pikaj00 — Sun Apr 18, 2010 4:54 am

new tricks

2010-04-01T10:23:10+01:00

I got a few new tricks in mind for my bioloid. With easter here I hope to do some stuff. Also I just got a SSD drive for my macbook. It is superfast now for me to make vid as well.

Statistics: Posted by UncleBob — Thu Apr 01, 2010 10:23 am

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2010-03-20T11:28:38+01:00

Hi,
well as far as i understand, the gyro is there to help stabilization.
so gyro response are calibrated not to disrupt motion page data send to the actuators if the robot does'nt need stabilization.
that is to say if the robot is walking on a flat surface for example.
but if it walks on a litlle irregular surface and the chest is starting to balance to much, then it will help to stabilize.

cheers
FabinovX.

Statistics: Posted by FabinovX — Sat Mar 20, 2010 11:28 am

gyro

2010-03-20T03:14:49+01:00

I just compare my robot (without a gyro) walking with one of my video on youtube. I cannot see any big difference.

Statistics: Posted by UncleBob — Sat Mar 20, 2010 3:14 am

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2010-03-16T20:34:33+01:00

Here is my new video :

phpBB [media]

and here is the code :

http://robosavvy.com/Builders/FabinovX/ ... o+arms.rar

Dont forget it will only work fine without modifications with a standard type A premium.

have fun

cheers
FabinovX

Statistics: Posted by FabinovX — Tue Mar 16, 2010 8:34 pm

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2010-03-16T15:39:06+01:00

did you try the code i did especially for you yesterday.
If not here it is :

FabinovX wrote:
Ok UncleBoB, try this with your type C, it should work fine :

http://robosavvy.com/Builders/FabinovX/ ... Type_C.rar

please, tell me if it really does or not.

File updated (i forgot to invert gyro offset with 9 and 10)

if you made modification to adapt the code with axs20, just paste the two line about ID 9 and 10 join offset in the callback and the whole function mesure_delta of this file to yours.

cheers
FabinovX

Statistics: Posted by FabinovX — Tue Mar 16, 2010 3:39 pm

y

2010-03-16T14:13:04+01:00

I finally get something working. The problem is due to the motion file in the robot is corrupted. I reupload it and it seems better. But the tsk file get the side mixed up. As soon as robot starts, it shift to one side. I try change 17 & 18 goal - position, it is better but not perfect. I think still need to change the sign of the formulae somewhere.

Statistics: Posted by UncleBob — Tue Mar 16, 2010 2:13 pm