eugene.katsevman's profile - activity

thank you!

Hello! I have some troubles understanding rpy. Here is my simple URDF file:

<robot name="test">
<link name="Body">
  <inertial>
    <mass value="4.0" />
    <origin xyz="1 0 0"/>
    <inertia ixx="1" ixy="1" ixz="1" iyy="1" iyz="1" izz="1" />
  </inertial>
  <visual>
    <geometry>
      <box size="0.1 0.02 0.02"/>
    </geometry>

  </visual>
</link>


<link name="link1">
  <inertial>
    <mass value="4.0" />
    <origin xyz="1 0 0"/>
    <inertia ixx="1" ixy="1" ixz="1" iyy="1" iyz="1" izz="1" />
  </inertial>
  <visual>
    <geometry>
      <box size="0.1 0.02 0.02"/>
    </geometry>

  </visual>

</link>


<joint name="j1" type="revolute" >
  <parent link="Body"/>
  <child link="link1"/>
  <origin xyz="0.1 0 0" rpy="0 -0.5 0" />
  <axis xyz="1 0 0"/>
  <limit lower="-1.57" upper="1.57" effort="10" velocity="10"/>
</joint>


</robot>

As you see, there are two links with a revolute joint between them. There is a pitch of -0.5 radians in the joint. And here is the rviz image :

The question is why link1 is rotated upwards instead of downwards?

strange pitch direction Hello! I have some troubles understanding rpy. Here is my simple URDF file: <robot name="tes

strange pitch direction Hello! I have some troubles understanding rpy. Here is my simple URDF file: <robot name="tes

btw, what's your linux distribution ?

Since the key is imported, it seems you have a different problem now and I think it is unrelated to ros. Please, open new question with the exact description of the current problem.

Sorry, can't write it here, but here is a link to cmake documentation on that matter : https://cmake.org/cmake/help/v3.0/com...

did you do sudo apt-get update ? Can you update your answer with new info, please?

can you try sudo apt-key adv --keyserver hkp://pool.sks-keyservers.net:80 --recv-key 421C365BD9FF1F717815A3895523BAEEB01FA116 instead?

So are you behind a proxy server?

You have to check how much of free ram is left on your arduino. If you run low on RAM, anything can happen.

http://playground.arduino.cc/Code/Ava...

If I got it correctly, I wouldn't bother with that and declared a pseudo-prizmatic joint for the gripper. Then you can transform linear coordinates of this pseudo-motor to angular for the real robot, using something like

arccos(linear_coord / dynamixel_radius)

reformat your message, please. Headers are broken.

Each package may consist of many different resources, e.g.

• tools, binaries or scripts like xacro which do their job quickly and then quit
• nodes, binaries or scripts like rviz or gazebo or joint_state_publisher which usually run all the time, participating in message processing and emitting.
• message and action specification
• configs and resources, which include urdfs, materials and images, yaml configs for ros_control
• libraries like tf or PyKDL or pid
• launch files, which run several tools/nodes at once
• maybe something else

So each of this resource types may utilize some other resource. Say, if your node have to communicate with some other node, you use messages. If it is your own message type, both of nodes (and their packages) should depend on the package with that message specification.

These are some mechanisms for utilizing other packages inside your own:

• adding a dependency on the other package in package.xml and CMakeLists.txt (if you need link other library to your code)
• using find_package in your launch files to refer files from other packages
• using package utils in runtime (cpp or python) to find resources from other packages (usually configuration, images and so on)
• using parameter server to prepare parameters for other nodes or to get it from there
• using messages and actions to communicate to other running nodes, possibly and usually originating from other packages

Hope this helps

please, accept this answer then

is your new class linked ? you'll have to modify CMakeLists.txt for that

or setup an alias setup="source devel/setup.sh" in your .bashrc or whatever shell you have there

Maybe it is because you're behind an http proxy. So other ports aren't working and some http tools are unaware of it.

Here is my pull request https://github.com/ros/robot_model/pu... The discussion has stopped for whatever reason.

Ok, so there is a bug in kdl_parser_py. You have to specify xyz AND rpy for link origins, otherwise they're be set to 0 both, ruining your model.

UPD: Here is the link to the pull request, which fixes the bug: https://github.com/ros/robot_model/pu...

thanks. In a while, could you tell me if there is a KDL alternative inside of ROS?

Hello! Could anyone share some tips and tricks? I've found that gravity should be 0, 0, -2 * 9.81 and this is strange. Another problem is that JntToGravity doesn't account for last chain link. I'm very confused with that and don't know where to look.

Hello! I can't find any information on it in kinetic. Is it still a thing? I even don't know how to install it

Hello! I've created a ros package with kdl_parser_py dependency. Now when I do catkin_make I get the following results:

CMake Error at /opt/ros/kinetic/share/kdl_parser_py/cmake/kdl_parser_pyConfig.cmake:141 (message):
  Project 'flax_assist' tried to find library 'kdl_parser_py'.  The library
  is neither a target nor built/installed properly.  Did you compile project
  'kdl_parser_py'? Did you find_package() it before the subdirectory
  containing its code is included?
Call Stack (most recent call first):
  /usr/share/catkin/cmake/catkinConfig.cmake:75 (find_package)
  flax_assist/CMakeLists.txt:7 (find_package)

But I'm sure kdl_parser_py is installed and rospack find kdl_parser_py works. How to use it then?

Hello! I've created a ros package with kdl_parser_py dependency. Now when I do catkin_make I get the following results:

CMake Error at /opt/ros/kinetic/share/kdl_parser_py/cmake/kdl_parser_pyConfig.cmake:141 (message):
  Project 'flax_assist' tried to find library 'kdl_parser_py'.  The library
  is neither a target nor built/installed properly.  Did you compile project
  'kdl_parser_py'? Did you find_package() it before the subdirectory
  containing its code is included?
Call Stack (most recent call first):
  /usr/share/catkin/cmake/catkinConfig.cmake:75 (find_package)
  flax_assist/CMakeLists.txt:7 (find_package)

But I'm sure kdl_parser_py is installed and rospack find kdl_parser_py works. How to use it then?