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ROS_CANOpen NMT (+jerk during PP-PV mode switch)

asked 2019-02-18 10:42:25 -0500

jxy gravatar image

updated 2019-02-18 10:44:42 -0500

Hello,

I am trying to implement on-the-fly mode switching between Profiled-Position and Profiled-Velocity mode using ROS_CANOpen. Unfortunately, my particular drive hardware (Elmo) produces an abrupt jerking motion during the switch, even if the robot is not in motion. To resolve this, I would like to switch the NMT state from Operational to Pre-Operational mode, process the mode switch, and then switch back to Operational.

Is there a provision for my situation in ROS_CANOpen? Does the stack provide a way to control the NMT? Or is there a better way to fix my jerk problem?

Thank you for reading

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answered 2019-02-18 11:11:42 -0500

jxy gravatar image

updated 2019-02-18 11:12:02 -0500

Fixed the issue. Solution is to set "switching_state" to 4 ("switched_on") in the driver.yaml config file as described in section 3 here: http://wiki.ros.org/canopen_motor_nod...

I believe what this does is put the drive into the pre-operational NMT state during mode switching to prevent unwanted movement from happening during the switch.

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I believe what this does is put the drive into the pre-operational NMT state during mode switching to prevent unwanted movement from happening during the switch.

No, the switching state refers to the 402 state machine.

Mathias Lüdtke gravatar image Mathias Lüdtke  ( 2019-02-18 13:21:53 -0500 )edit

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Asked: 2019-02-18 10:42:25 -0500

Seen: 45 times

Last updated: Feb 18 '19