How to control Maxon Motor by using ROS_CANopen

asked 2016-12-16 04:03:02 -0600

CJ.Nilson
23 ●3 ●4 ●9

updated 2016-12-26 12:22:20 -0600

Hi all,

I am a newbie to ROS, I would like to use ROS_CANopen package to connect with my robot, I want to set different modes of operation for position and current control. After that, I would like to use MoveIt to control my robot. However, I checked from previous ROSAnswer about ROS_CANopen can not find more detail tutorials on how use it.

Here is my hardware configuration:

A USB-to-CAN compact made by IXXAT is used to communicate between my laptop and the robot. The Linux driver called IXXAT socketcan driver.
The robot uses Maxon EPOS2 with CANopen. eds file is generated from EPOS studio.

OS: Ubunutu 14.04 with indigo installed. I already tested with socketcan driver by using can-utils i.e. cansend can0 xxx. Therefore, I can just use CANopen protocol-301 and 402 with command-line to control Maxon motor, in the meantime, use sockketcan_dump to verify command and status.

How to use Ros_CANopen? could someone give me a hint to do next steps or some examples I could refer to? or any package to run roslaunch to control ROS_CANopen?

Many thanks,

edit retag flag offensive close merge delete

Comments

Excuse me, I now have a USB-to-CAN device (kvaser leaf light v2), a motor! I want to know how to use ROS_CANopen and socketcan_driver to control motor rotation? Can you tell me what to do? This problem has been bothering me for a long time, please!

FAN ( 2019-08-16 07:43:45 -0600 )edit

add a comment

answered 2016-12-16 05:40:03 -0600

Mathias Lüdtke

1596 ●2 ●26 ●26

updated 2016-12-16 05:40:40 -0600

It should be more or less straightforward:

Setup SocketCAN (you already have this running): http://wiki.ros.org/socketcan_interfa...
Prepare URDF with sane limits (this is required for now, will be optional in the future): http://wiki.ros.org/urdf/Tutorials/Cr...
Prepare EDS/DCF, take special care for the PDO mapping ( http://wiki.ros.org/canopen_402 ), use transmission type 1 (every sync)
Prepare driver config
- prepare chain config ( http://wiki.ros.org/canopen_chain_nod... )
- configure motor-specific settings, especially unit conversions ( http://wiki.ros.org/canopen_motor_node )
Prepare controller config
- list of controllers (documentation varies, http://wiki.ros.org/ros_controllers )
- add a required_drive_mode to each motion controller, it takes the number of the mode to be used ( http://wiki.ros.org/canopen_402#Drive... )
Prepare a launchfile for canopen_motor_node
- upload driver config as private parameters
- upload controller config into namespace
- upload robot description
rosservice call [/namespace]/driver/init ( http://wiki.ros.org/canopen_chain_nod... )
start/switch the controllers (rqt_controller_manager, ontroller_manager, spawner etc.)

The EDS file parser is not really bullet proof (and EDS file format is rather flexibel) and might fail with some error indication. In addition ros_canopen enforces strict typing, some EDS files list non-standard types for some objects (e.g. signed instead of unsigned). This must be fixed as well in the EDS.

A basic driver config looks like:

bus:
  device: can0
sync:
  interval_ms: 10  # 100Hz
  overflow: 0
defaults:
  eds_pkg: my_package
  eds_file: "config/MyDescription.dcf" # the parser reads EDS and DCF
nodes:
  my_joint:
    id: 1

controller config example: https://github.com/ipa320/canopen_tes...

Fairly complex examples: https://github.com/ipa320/schunk_robots/

It would be great if you could turn this into a tutorial on ROS Wiki based on your experiences :)

edit flag offensive delete link

Comments

Thank you for the replies. I still have some questions regarding your replies.

item 2: I have created URDF to describe elements fo my robot, but why need URDF in ros_canopen
item 5: Why ros_canopen package need ros_control? Could you briefly introduce the main idea for using ros_control

CJ.Nilson ( 2016-12-19 12:19:51 -0600 )edit

I'm trying to refer "schunk_robots and canopen_test_utils" as a model for item 4, 5 and 6. Which packages do you recommend for my case? Thanks you very much.

CJ.Nilson ( 2016-12-19 12:30:52 -0600 )edit

The URDF is used for getting the joint limits and to verify the names of the joints.

More information on ros_control can be found in the wiki: http://wiki.ros.org/ros_control And schunk_robots contains full-fledged examples.. If in doubt have a look at both.

Mathias Lüdtke ( 2016-12-19 17:19:02 -0600 )edit

When I tried to do item 7 you listed, I met the failure during initializing the lwa4d, have you ever meet this before ? Thanks for your reply

CJ.Nilson ( 2016-12-23 01:28:02 -0600 )edit

Hello CJ and Mathias, please, could you help me with a similar problem in this question: #q292882

Many thanks, Jorge

jdeleon ( 2018-06-01 01:41:44 -0600 )edit

@Mathias Lüdtke , When you say use transmission type 1, that is for both RxPDO and TxPDO ?

Cyril Jourdan ( 2018-12-06 04:38:45 -0600 )edit

Yes, for both. This is how we run it with Care-O-bot. It is not mandatory, but it enforces a deterministic data flow. Otherwise the timing would be arbitrary and might result in (small) jumps.

Mathias Lüdtke ( 2018-12-10 09:49:44 -0600 )edit

hi @Mathias Lüdtke , following your steps to successfully control the motor, is user supposed to write and implement some additional hardware interface for Maxon motor, or it is yet included in ros_canopen packages?

martinlucan ( 2021-07-06 07:23:37 -0600 )edit

see more comments

How to control Maxon Motor by using ROS_CANopen

Comments

1 Answer

Comments

Question Tools

Stats

Related questions

How to control Maxon Motor by using ROS_CANopen edit

Comments

1 Answer

Comments

Question Tools

Stats

Related questions

How to control Maxon Motor by using ROS_CANopen