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polling rates

asked 2016-05-08 04:59:54 -0600

Fighting_bird gravatar image

updated 2016-05-17 01:42:48 -0600

mgruhler gravatar image

I have problem in this concept "polling rates", and I only knew it determines how fast the outside ROS loop runs. But I still can't understand it. Who can tell me something specific or give me a example? This is the document where I met this concept https://github.com/hbrobotics/ros_arduino_bridge#configuring-the-ros_arduino_python-node.And the you can find the "polling rates" easily in it.

Polling Rates

The main rate parameter (50 Hz by default) determines how fast the outside ROS loop runs. The default should suffice in most cases. In any event, it should be at least as fast as your fastest sensor rate (defined below).

The sensorstate_rate determines how often to publish an aggregated list of all sensor readings. Each sensor also publishes on its own topic and rate.

The use_base_controller parameter is set to False by default. Set it to True to use base control (assuming you have the required hardware.) You will also have to set the PID paramters that follow.

The base_controller_rate determines how often to publish odometry readings.

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Can you be more specific? What are you talking about exactly? When googling for "ROS polling rate", the only hits are something with specific hardware, e.g. an Arduino board. Please link to something documented (wiki, github), where you are unsure. (and please edit your question)

mgruhler gravatar imagemgruhler ( 2016-05-09 01:19:52 -0600 )edit

Very sorry! I will edit my question at once.

Fighting_bird gravatar imageFighting_bird ( 2016-05-13 23:46:44 -0600 )edit

@struggling_bird please don't post any screenshots, as they are not searchable and the question will not make sense anymore, if the image ever disappears. You can easily copy-paste this code and format it properly using one of the preformatted text buttons...

mgruhler gravatar imagemgruhler ( 2016-05-17 01:41:36 -0600 )edit

@mig Thank for your reminding all the same, even though I didn't post any screenshots. And I will keep in mind it to avoid making this mistake.

Fighting_bird gravatar imageFighting_bird ( 2016-05-19 10:58:26 -0600 )edit

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answered 2016-05-17 01:49:40 -0600

mgruhler gravatar image

updated 2016-05-17 01:50:42 -0600

This is actually not really a ROS concept. At least, in the ROS world, you usually don't talk about "polling". The concept in ROS is actually called spinning.

In this specific case, this means how often you publish respective messages (sensor and odometry), as written in the docu. The rate parameter specifies, how often the main loop here is actually running. This main loop is polling the sensor and odometry data and publishing it.

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I've got it! Thank you very much.

Fighting_bird gravatar imageFighting_bird ( 2016-05-19 10:53:22 -0600 )edit

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Asked: 2016-05-08 04:59:54 -0600

Seen: 715 times

Last updated: May 17 '16