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BRobot Oscillation then fall over
06-24-2017, 05:25 PM
Post: #11
RE: BRobot Oscillation then fall over
Update: I took out and checked the IMU just with an Uno, and the readings appeared sensible and stable. I also placed it back into the robot and checked the values (DEBUG = 3) through the serial port both with and without the battery pack connected. There didn't appear to be any corrupt data. Replaced the A4988 stepper drivers with a couple of spare ones I had lying around, but that made no difference. Can't think what else to try.

Has anyone else on the forum experienced this? I go through the calibrate procedure, then lift the robot upright. The stepper motors make a whining sound until the robot is stable and upright, which does seem a bit odd. The robot will often stay upright, but the slightest movement will make it rock back and forth until it falls over. Someone out there must know the answer! Please!
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06-26-2017, 06:51 PM
Post: #12
RE: BRobot Oscillation then fall over
The only thing to blame here: the motors. Can you try another type of stepper motors? Have you tried to trim the stepper motor drivers?
Take a look to :"My B-robot lacks of power or fall without reason" here
http://www.jjrobots.com/b-robot-evo-2-assembly-guide/
Maybe the stepper motors you are using demand more current to deliver enough torque
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06-26-2017, 07:49 PM
Post: #13
RE: BRobot Oscillation then fall over
(06-26-2017 06:51 PM)jpedroc Wrote:  The only thing to blame here: the motors. Can you try another type of stepper motors? Have you tried to trim the stepper motor drivers?
Take a look to :"My B-robot lacks of power or fall without reason" here
http://www.jjrobots.com/b-robot-evo-2-assembly-guide/
Maybe the stepper motors you are using demand more current to deliver enough torque

I bought the stepper motors and drivers from JJRobots, so I assume they will work correctly. However, I will take a look at the article suggested and see what happens.
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06-30-2017, 11:49 AM
Post: #14
RE: BRobot Oscillation then fall over
(06-26-2017 07:49 PM)Bondo Wrote:  
(06-26-2017 06:51 PM)jpedroc Wrote:  The only thing to blame here: the motors. Can you try another type of stepper motors? Have you tried to trim the stepper motor drivers?
Take a look to :"My B-robot lacks of power or fall without reason" here
http://www.jjrobots.com/b-robot-evo-2-assembly-guide/
Maybe the stepper motors you are using demand more current to deliver enough torque

I bought the stepper motors and drivers from JJRobots, so I assume they will work correctly. However, I will take a look at the article suggested and see what happens.

Tried everything, including powering the robot with my external supply. The robot just makes a whining sound, and when it does eventually stand up, it will thrash around for a few seconds then fall over. Frankly I'm disappointed with this thing, and will probably trash it and start again with a new design, not using the Brainshield. I have a feeling the brainshield and/or software is responsible - I have replaced everything else without success, so it cannot really be anything than that.
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07-01-2017, 08:58 PM
Post: #15
RE: BRobot Oscillation then fall over
Bondo, we can take a look to the PCB if you want. Contact us at info@jjrobots.com, if the Brain shield is faulty we will send you a replacement
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07-15-2017, 11:45 AM
Post: #16
RE: BRobot Oscillation then fall over
Finally got to the bottom of this drunken bot syndrome. The wheels were ever-so-slightly loose on the stepper axles, so the robot could never maintain balance. I have glued the things on now, and it stays upright. Thanks to the JJRobot guys for all their help.

Now just have to figure out why it won't go backwards!
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07-18-2017, 09:27 AM
Post: #17
RE: BRobot Oscillation then fall over
Nice! We will add a sort of warning message to the assembly guide for other MAKERs. ;-)
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