One motor slowing down (stopping)

General discussion of using Roboclaw motor controllers
Post Reply
felix
Posts: 19
Joined: Thu Dec 03, 2020 8:08 am
One motor slowing down (stopping)

Post by felix »

Hi,
I'm working on a rather big robot (80kg), with 4 wheels which a motor and an encoder for each one.
The 2 front motors are connected on a first roboclaw (dual 60A version), and the 2 rear motors on a second one.
We are using a single UART connexion to a Jetson Xavier AGX computer (using the ros interface), with the first roboclaw transmitting the commands to the second one.

We are using the setup for quite some time yet, and so far everything was OK.
On monday, twice, we had one wheel blocked or nearly blocked (it rotated very slowly, probably only because the robot was still moving forward). At that point, I didn't wrote down which wheel was concerned.
Then, the problem disappeared until this morning.
This morning, the problem appeared again about 10 times, each time on the same wheel (the right rear one).
There was one sharp right turn were it appeared very often (about once every second time), but we had the same problem at least once on a straight section (maybe there was an acceleration, I can't say)

After a complete reset of the robot (shutting down the computer, powering off the robot, turning everything on again), the problem disappeared.


Do you have any idea where the issue might come from or how to investigate it? (knowing that I don't know of any way to reproduce the error)



Thanks a lot in advance
Felix

PS : I attach the code of the ros node doing the interface with the roboclaws library : as far as I can tell, there is no way to send a different command to the front and rear motors of the same side.
Attachments
roboclaw_node.zip
(1.78 KiB) Downloaded 148 times
User avatar
Basicmicro Support
Posts: 1594
Joined: Thu Feb 26, 2015 9:45 pm
Re: One motor slowing down (stopping)

Post by Basicmicro Support »

Adjust the current blanking setting for that motor channel. Your symptom could be cause by false over currents a t low duty cycles. Values between 8 and 10% are usual but you can go as high as 20%.

Post Reply