> For the complete documentation index, see [llms.txt](https://campus-rover.gitbook.io/lab-notebook/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://campus-rover.gitbook.io/lab-notebook/fiiva/cr-package/navigation/cpu-usage-and-errors-in-navigation.md). # cpu-usage-and-errors-in-navigation.md During navigation I've run into a lot different errors and warnings. I copied some of the frequent ones here: ```sh [ WARN] [1542144731.816164220]: Costmap2DROS transform timeout. Current time: 1542144731.8160, global_pose stamp: 1542144730.2532, tolerance: 1.5000 [ WARN] [1542144731.816266907]: Could not get robot pose, cancelling reconfiguration [ WARN] [1542144732.472418469]: Unable to get starting pose of robot, unable to create global plan [ WARN] [1542144726.841978275]: Map update loop missed its desired rate of 1.0000Hz... the loop actually took 1.2625 seconds [ WARN] [1542144737.244639028]: Map update loop missed its desired rate of 5.0000Hz... the loop actually took 0.2093 seconds [ WARN] [1542144737.244865990]: Control loop missed its desired rate of 3.0000Hz... the loop actually took 0.8109 seconds [ERROR] [1542146023.217567014]: Extrapolation Error: Lookup would require extrapolation into the future. Requested time 1542146022.709356378 but the latest data is at time 1542146021.995298140, when looking up transform from frame [odom] to frame [map] [ERROR] [1542146023.217646860]: Global Frame: odom Plan Frame size 1889: map [ WARN] [1542146023.217688426]: Could not transform the global plan to the frame of the controller [ERROR] [1542146023.217720997]: Could not get local plan ``` What I found in common from these problems is that they all have something to do with information loss in the update cycle of different parts of navigation. And this could be caused by computer not having enough processing power for the desired update frequency, which is actually not high at all, like the 1.0000Hz and 5.0000Hz in the warning messages above. Then I found that the laptop's both CPUs' usage is nearly at 100% during navigation. I checked each node one by one. Rviz is very CPU-hungry, when running navigation and rviz together, the CPUs will have nearly 100% usage. But we can avoid using rviz once we have fiducial working. Besides Rviz, several custom nodes made by us are also very CPU-hungry. For now, we are using Dell 11 inch laptop as the onboard computer for Turtlebot. The situation might not be the same if more powerful devices are used. However, generally speaking, in our custom nodes we should avoid pulishing/updating with a frequency that's too high. Also please remember to check CPU usage if you find these errors and warnings again during navigation. ## *Huaigu Lin 11/13/2018* --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://campus-rover.gitbook.io/lab-notebook/fiiva/cr-package/navigation/cpu-usage-and-errors-in-navigation.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.