takahashi's profile - activity

I didn't really get the concept of nodehandles from the ROS wiki and couldn't find any concise answer with google. I understood that a ROS node can have multiple nodehandles and they refer to the same node. In a node's main(), I first initialize the node using ros::Init() and then use a nodehandle for starting and shutting down the node. So what does the declaration of multiple nodehandles do in this case?

I am confused by the Nodelet Docs regarding the two possibilities to run a nodelet (1.4 Basic Usage). Apparently, one can either

• launch one nodelet manager and load multiple nodelets into this manager or

• launch multiple standalone nodelets in different nodes.

  Is the communication between nodelets still zero-copy, if I launch them as standalone nodelets?

I have a catkin workspace that contains multiple packages, however I would like to install the catkin workspace to a Install directory, with only a few selected packages instead of all packages. Is this possible?

I am currently looking into versioning my catkin packages and making sure that I am using the correct versions. I am using Package Manifest Version 2 and according to REP-140, I should be able to specify the versions of my dependencies.

E.g. I have a package A (version 1.1) and a package B that depends on package A. I now would like to make sure, that version 1.1 of package A is used when building package B. My package.xml's will contain the following (for the sake of simplicity, I only include the relevant parts):

package A package.xml

<?xml version="1.0"?>
  <package format='2'>
  <name>A</name>
  <version>1.1.0</version>
  ...
</package>

package B package.xml

<?xml version="1.0"?>
  <package format='2'>
  <name>B</name>
  <version>1.0.0</version>
  <depend version_eq="1.1.0">A</depend>
  ...
</package>

So far so good, everything compiles fine. However, if I change that depend tag in package B package.xml above, e.g. to

<depend version_eq="2.0.0">A</depend>

..it still compiles fine! Meaning that it just does not care about the version attribute.

What am I doing wrong?

Edit: I just noticed that a warning is printed:

catkin_package() version mismatch: the package.xml of 'B' build_depends on 'A = 1.0.0', but 'A 0.9.0' found

Is this the expected behaviour or should the build fail?

First of all, thanks a lot for the quick&clarifying answers! But if the manifest is used for different things, why i

I found out that in the catkin_package.cmake script only a WARNING is printed upon a version mismatch, so this behaviour

Package Manifest 2 - <depend> attribute version does not work I am currently looking into versioning my catkin pac

Package Manifest 2 - <depend> attribute version does not work I am currently looking into versioning my catkin pac

I wrote a custom display type for RViz (see e.g. here) and I would like to have an icon displayed, when I browse for it in RViz.

In the above link, I see that there is a OculusDisplay.png in the directory icons/classes/.., but I can not figure out, how to link this. Does anybody know how this is done?

As I was not able to find this information in the documentation of the robot_localization package nor its source code, does anybody know what the "internal motion model" is that is used in theekf_robot_localization node?

Edit: In the corresponding paper, the authors state that they use a "standard 3D kinematic model derived from Newtonian mechanics", but I guess this model is derived from the kinematics of the test platform they used for the experiments.