Thanks Tully,
I got the answer from Mike Ferguson, author of the ArbotiX ROS package
and he said to try turning down the servo controller rate to 1Hz instead
of 15Hz and now things are working A-OK. Apparently trying to read the
servo positions at that rate while also writing to them can cause some
weirdness as I saw.
--patrick
On 01/16/2011 03:14 PM, Tully Foote wrote:
> Patrick,
>
> I'm going to think about this more, but in the mean time I'd suggest you
> check the clock synchronization between your two machines with ntp?
> This could be caused by the joint states or something being backdated.
> The robot_model display in rviz does some tricks to keep the model
> display updated for better viewing.
>
> In general debugging I'd suggest tf_monitor and roswtf to start.
>
> Tully
>
> On Sun, Jan 16, 2011 at 1:33 PM, Patrick Goebel <patrick@pirobot.org
> <mailto:patrick@pirobot.org>> wrote:
>
> Hello All,
>
> I'm trying to teleoperate a robot that uses Dynamixel AX-12+ servos
> using a Kinect and the openni_tracker node. I'm posting here instead of
> ros-kinect because I don't think it is a Kinect or OpenNI issue. I use
> tf.TransformListener in my Python joint controller program and map
> skeleton frames from openni_tracker into translations and rotations of
> the joints. If I do everything in RViz on my virtual URDF robot model,
> there is no delay between my movements in the Sample-NiSimpleViewer and
> the robot in RViz. However, when I connect the real robot using a
> USB2Dynamixel, there is a delay of 3-5 seconds between my movements and
> the robot's movements.
>
> The USB2Dynamixel is hardwired to both the robot and the controlling PC
> so there is no wireless link involved. I am running the ArbotiX ROS
> package to control the servos and my servo polling rate is 15Hz. I am
> running the joint controller node also at 15Hz and it publishes
> JointState commands at that rate to the servo controller.
>
> Does anyone have an idea where the delay might be seeping in? I'm happy
> to provide more details if needed.
>
> Thanks!
> Patrick Goebel
>
> Behavioral Sciences
> Stanford University
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>
>
> --
> Tully Foote
> Systems Engineer
> Willow Garage, Inc.
> tfoote@willowgarage.com <mailto:tfoote@willowgarage.com>
> (650) 475-2827
>
>
>
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