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dynamixel_controller update rate

asked 2014-02-05 03:00:55 -0500

sertar gravatar image

hi, I interact with dynamixel motors using dynamixel_controllers. Is it possible to make the servos sending feedback at different rates ? For example i want the legs of the robot to send feedback more often than the arms. In manager.launch i can set the rate for all motors in one serial connection but i can't set different rates for motors inside the same serial connection.

Thanks in advance

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answered 2014-02-05 07:11:35 -0500

arebgun gravatar image

No, it's not possible to set different polling rates for different sets of servos connected to the same serial bus. It would increase traffic on the serial bus and decrease the maximum polling rate possible. Right now we are just asking to get the updated info on all motors in one go. You could split the leg servos and connect them separately which would also increase the maximum feedback rate as you have less motors on the line to collect info from.

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Thank you for your fast answer. Is it possible though to turn on and off some controller dynamically ? i tried with the stop_controller service but it does not improve the polling rate of motors still turned on.

sertar gravatar image sertar  ( 2014-02-05 10:03:18 -0500 )edit

I am not sure, it depends on how many motors are connected, if you have 10 and you disable 1, it is unlikely you will see a significant difference.

arebgun gravatar image arebgun  ( 2014-02-07 16:15:31 -0500 )edit

No i have 30 and i disable 15. if i launch a different manager with only the remaining 15 i see a difference but not when i shut them down with stop_controller (i see on rqtgraph that the controllers are off).

sertar gravatar image sertar  ( 2014-02-08 07:39:54 -0500 )edit

Right, the motors are polled at startup and then that list is not changed until the node is shut down. I think it would be possible to modify this list of motors at runtime and only query the motors associated with started joints. Could you open a feature enhancement ticket on github?

arebgun gravatar image arebgun  ( 2014-02-10 11:13:31 -0500 )edit

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Asked: 2014-02-05 03:00:55 -0500

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Last updated: Feb 05 '14