I measured the time between when the robot receives a command (directly into the kobuki_node) and when it starts to move (as measured from odometry), and it's about **200ms**, sometimes more. Looking at serial line delay, delays in the driver, the sensor data rate, and so on, I could only explain about 50ms of that. That leaves 150ms which is somehow lost in the firmware.
Am I doing something wrong here, or is this normal?
Check out this image for a visualization: Top plot is the command, bottom plot is the odometry velocity. I tested pure rotation.
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%20of%20200ms?&References=topic/4443@discourse.ros.org&In-Reply-To=topic/4443@discourse.ros.org&CC=%22Ingo%20L%C3%BCtkebohle%20via%20ros-users%22%20<noreply@ros.org>,%20%22Ingo%20L%C3%BCtkebohle%22%20<ros.discourse@gmail.com>&Body=On%202018-04-12%2016:27,%20Ingo%20L%C3%BCtkebohle%20via%20ros-users%20wrote:%0A>%20%0A>%20%0A>%20I%20measured%20the%20time%20between%20when%20the%20robot%20receives%20a%20command%20(directly%20into%20the%20kobuki_node)%20and%20when%20it%20starts%20to%20move%20(as%20measured%20from%20odometry),%20and%20it's%20about%20**200ms**,%20sometimes%20more.%20Looking%20at%20serial%20line%20delay,%20delays%20in%20the%20driver,%20the%20sensor%20data%20rate,%20and%20so%20on,%20I%20could%20only%20explain%20about%2050ms%20of%20that.%20That%20leaves%20150ms%20which%20is%20somehow%20lost%20in%20the%20firmware.%0A>%20%0A>%20Am%20I%20doing%20something%20wrong%20here,%20or%20is%20this%20normal?%0A>%20%0A>%20Check%20out%20this%20image%20for%20a%20visualization:%20Top%20plot%20is%20the%20command,%20bottom%20plot%20is%20the%20odometry%20velocity.%20I%20tested%20pure%20rotation.%0A>%20!%5Bcontrol_latency_vendor_driver_crop%7C690x418%5D(upload://miBXkJQ4pLLti9xXLgKdzryiQrl.png)%0A>%20%0A>%20%0A>%20%0A>%20%0A>%20%0A>%20---%0A>%20%5BVisit%20Topic%5D(https://discourse.ros.org/t/turtlebot2-control-dead-time-latency-of-200ms/4443/1)%20or%20reply%20to%20this%20email%20to%20respond.%0A>%20%0A>%20%0A>%20If%20you%20do%20not%20want%20to%20receive%20messages%20from%20ros-users%20please%20use%20the%20unsubscribe%20link%20below.%20If%20you%20use%20the%20one%20above,%20you%20will%20stop%20all%20of%20ros-users%20from%20receiving%20updates.%0A>%20______________________________________________________________________________%0A>%20ros-users%20mailing%20list%0A>%20ros-users@lists.ros.org%0A>%20http://lists.ros.org/mailman/listinfo/ros-users%0A>%20Unsubscribe:%20<http://lists.ros.org/mailman//options/ros-users>%0A>%20%0A>%20 "Reply to this message")
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