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panthallion
04-23-2015, 09:26 AM
Hi Engineers :-),

I have a small issue with the servo number 13 Knee, everytime I power on the robot, everything is fine, no blinking red led.

When I issue a "./start_ps3demo", after 30 sec staying in the Stand-Up possition or issueing a Walk motion, the servos #13 fail, blink with a red led and no more torque so the PS3 Demo jam, I have to redo everything from start and power-off HR-OS1.

I have reflash to original firmware with Roboplus and USB2DYNAMIXEL adapter, and same thing happen again, everything is fine for 30 sec to 1 min after that the server runs hot and fail. :-(, any idea?

Also, when you do a ./dxl_monitor and you receive a FAIL for 1 to 3 servos (while robot in Sit Position), what does that mean?

Thanks a lot

kgranat
04-23-2015, 11:11 AM
Do you think you can swap out the Knee servo for one of the servos in the upper body (maybe servo 3 or 4)? You will need to swap the IDs via dxl_monitor. If everything works with the servos swapped, the AX-12 itself may have a problem, in which case we can get an RMA set up.

Are you using the Raspberry Pi or the Intel Edison?

panthallion
04-23-2015, 11:21 AM
Do you think you can swap out the Knee servo for one of the servos in the upper body (maybe servo 3 or 4)? You will need to swap the IDs via dxl_monitor. If everything works with the servos swapped, the AX-12 itself may have a problem, in which case we can get an RMA set up.

Are you using the Raspberry Pi or the Intel Edison?

Hi, I am using the Raspberry Pi 2.

Ok I will try to do that, so if the servos fail even when it<sin the upper body then it is faulty right?

There's is no other way like a config via dxl_monitor to set or something?

Thanks a lot.

tician
04-23-2015, 12:14 PM
It may be that the servo offset calibration is a bit off and one leg is taking much more than half of the total load, so one knee is overheating faster than the other knee. If it is uneven loading, then it can appear that the bot is leaning ever so slightly to one side. It may also be a snagged cable causing excessive loading on the servo, since 30~60s overheating sounds more like something experienced with an AX-18.

Even the MX humanoids require offset calibration due to variations in link lengths and frame offsets during frame construction and bot assembly. It is somewhat of an art, and involves making the bot's idle pose look like the reference images and then pushing/pulling on the joints and lifting the bot off the ground at the nape of the neck/shoulders (where the webbing handle is on the DARwIn-OP) to see if the servos are really centered where they appear. The legs and hips tend to be most sensitive to offset errors that can cause serious issues in walking (IIRC, I actually had the DARwIn-OP with hips directly above ankles and the torso leaning forward at the hips a bit more than the references).

edit: now that I think about it again, I may have also adjusted the offsets so that the hip and ankle modules were also parallel (so that there was symmetry of the upper and lower leg about the knee joint) with the hips tilting the torso forward a bit from vertical for very reliable walking on tile and low pile, unpadded carpet (always falls on the metal transition strip between the two). Not sure how the HR-OS1 is supposed to look, although it does (did?) use the DARwIn-OP walking module.

panthallion
04-23-2015, 12:32 PM
YES!! Correct, my robot lean on the left (when facing the robot, so for the robot, it leans on his RIGHT Knee) because there a bit of offset on the left leg where I think the load is too much on the right knee. So maybe the servo is not broken but only get too much off load and shutdown after 30 - 60 sec right?

Is there a tool in the framework that I can use to modify the offset, so everytime I turn on the HR-OS1, the pose (sit down, walk, stand-up,etc..) are ok.

What dis you do and I don't see any pose reference for HR-OS1 (sit down and stand up poses)

Cheers,

panthallion
04-23-2015, 01:34 PM
Can someone help me ajusting the stand up default pose with the right offset values please? All the load is on the right leg because my pose is not perfect, that causes server #13 Knee on the right leg to shutdown the torque and blink red.

Cheers,

Jonathan

DresnerRobotics
04-23-2015, 01:52 PM
You should not have to adjust the default pose or change offsets. I'd imagine something on your build is incorrect, or the servo itself is having problems.

DresnerRobotics
04-23-2015, 01:53 PM
The offset code in the Darwin-OP framework is very poorly implemented, so we pulled it out for the time being.

I'd imagine that your issues are related to a physical issue with the servo, either alignment or a bad servo.

panthallion
04-23-2015, 01:56 PM
Every servo horns are aligned perfectly from build...

Ok So I have to contact Rick at Trossen Robotic for that right? or [email protected]?

Thanks

panthallion
04-23-2015, 02:22 PM
Ok so I have to change the servo that causes the wrong default pose value?

Cheers

tician
04-23-2015, 02:45 PM
The offset code in the Darwin-OP framework is very poorly implemented, so we pulled it out for the time being.

I'd imagine that your issues are related to a physical issue with the servo, either alignment or a bad servo.
Pulled it out? From where? The Interbotix/HROS1-Framework on github still possesses the extremely simple and effective "add the offset value to the servo goal immediately before performing the sync_write to all servos by the motion manager" so that any pose/motion or gait could be 'universal' with the offsets correcting for individual variation of the robot from the 'ideal'. How those are offset values are loaded into the motion manager could be an issue if the functions that load the values do not understand signed integers correctly, but the implementation in the motion manager is very simple and very necessary. Every single DARwIn-OP, Type-A humanoid, and gerwalk in the lab required different offsets to correctly balance when playing motions or gaits, and would be unable to walk straight or stay upright while moving without those corrections. Recalibration of offsets is part of standard maintenance and has to be done after every servo or frame replacement, after major falls/collisions, and after every however many hours of use (screws loosen, frames shift, frames deform, etc.).

panthallion
04-23-2015, 03:53 PM
I perfectly agree with that, and I think it's the basic of every construction to recalibrate the offset but I don't see How can I manage that with HR-OS1, i tried connecting the Arbotic to Roboplus, it found the board but dont see the servos...

And I don't know if there's a tool "cli" in the HROs1 Framework to write the correct value for each servos, correct them and save for initial posture...

kgranat
04-23-2015, 05:01 PM
You can use the ArboitX Pro with the DYNAMIXEL wizard, but you need to turn power onto the servo chain. See instructions here
https://www.youtube.com/watch?v=SCO_8nrldDE

You can contact me via e-mail about a possible servo RMA

[email protected]

DresnerRobotics
04-23-2015, 06:03 PM
Pulled it out? From where? The Interbotix/HROS1-Framework on github still possesses the extremely simple and effective "add the offset value to the servo goal immediately before performing the sync_write to all servos by the motion manager" so that any pose/motion or gait could be 'universal' with the offsets correcting for individual variation of the robot from the 'ideal'. How those are offset values are loaded into the motion manager could be an issue if the functions that load the values do not understand signed integers correctly, but the implementation in the motion manager is very simple and very necessary. Every single DARwIn-OP, Type-A humanoid, and gerwalk in the lab required different offsets to correctly balance when playing motions or gaits, and would be unable to walk straight or stay upright while moving without those corrections. Recalibration of offsets is part of standard maintenance and has to be done after every servo or frame replacement, after major falls/collisions, and after every however many hours of use (screws loosen, frames shift, frames deform, etc.).

I was seeing pretty consistent results among our robots here, my HROS5's don't need any offset calibration at all, and so far I have multiple HROS1 walking without it as well. With that said, I intend on bringing the 'offset_tuner' app back into the fray, but I was having issues with it's consistency between the walking gait IK and the poses that action_editor creates so I pulled 'offset_tuner' out of the repo until I could figure out what was wrong there. I had the same issues with it on my original Darwin-OP.

oesile
04-30-2015, 01:03 PM
Hi all,

I have the same issue even in the same servo #13.... (mabe it is an evil number :tongue:). I am using Intel edison, I do not have problems with the dxl_monitor everything is OK. My problem started running rme init slow. So, what is the recommendation? ยจ

@panthallion, did you find any solution?

kgranat
04-30-2015, 01:26 PM
You can e-mail me and we'll get a return setup for your servo. E-mail me your order number
[email protected]

panthallion
05-01-2015, 07:16 AM
Hi, Trossen Robotics had gently send me replacement servo, thanks to you guys, great support.