Usage of this driver?

[aaravrav142]

Hi,

I have been searching for a ros driver for roboclaw motor controller and a search brought me to this driver.
Just wanted to know how to use this package with ROS. Does the robot needs to be precalibrated for PID values using the roboclaw software. Also, if the connection using USB to PC is ok to use? I plan to use it on an electric wheelchair and later port it on another robot with beefy motors (differential drive only). I am really interested in this so any help will be deeply appreciated. Thanks a lot.

[girtslinde]

This driver is for the old protocol. They have switched to a better - two-byte checksum since then. If you got your roboclaw in the last two years it probably talks the new protocol.

The downloads page http://www.ionmc.com/downloads points to this ROS driver https://github.com/sonyccd/roboclaw_ros. Have you tried it? I think I tried it a while ago and something didn't work for me.
Also, a member of our robot club made a driver for his robot, and it included a roboclaw driver. Look around here https://github.com/mwimble/Ianthe/tree/master/farryn_controller, see if it helps. I think it talked the new protocol and worked quite well.

Regarding USB, it can be used. But I have heard people complain that USB was not stable. We used serial on our robot, just to be safe.

[aaravrav142]

Hi,

Sorry for the late reply. The roboclaw_ros driver by sonyccd does not work nicely as stated. There are many problems with the USB connectivity and the package still does not correspond to the odom values. Moreover using teleop key and pressing keys for long duration results in node crashing.

The farryn_controller is a great package. I have been studying it for some time and more or less it works. Its not out of the box thing and require several tuning. I am still unable to get how the PID values are set there. Since the package was written specifically for a custom robot, I am not sure how to incorporate bits and pieces from the code to a general differential drive robot. I believe SV-ROS can help me with the setup and how to configure the PID values. I used the ion motion software(windows) to auto tune the motors and get the values of PI and QPPS for the dc motors that I am currently using (Pololu 100:1 gear ratio, 100RPM with 64 CPR), I cannot get the robot to move nicely. The motors move but are jerky.
Any further help would be deeply appreciated.
Thanks