patrchri's profile - activity

Hello,

I am running ROS melodic on a NVIDIA Jetson Nano and I am at the stage of simulation of a rover. To be more specific I have created the following rover (see XML code below) and I am trying to move its two continuous joints (essentially the two wheels) with a certain velocity. For this reason I am trying to use ros_control and more specifically effort_controllers/JointVelocityController. Below I have attached my config.yaml file as well as the spawn launch file I use to spawn the model in gazebo. My issue is that I get the following error in the command window when I try to run this:

SUMMARY
========

PARAMETERS
 * /rosdistro: melodic
 * /rosversion: 1.14.10
 * /rover/joint_left_wheel_velocity_controller/joint: joint_left_wheel
 * /rover/joint_left_wheel_velocity_controller/pid/d: 50
 * /rover/joint_left_wheel_velocity_controller/pid/i: 10
 * /rover/joint_left_wheel_velocity_controller/pid/p: 1000
 * /rover/joint_left_wheel_velocity_controller/type: effort_controller...
 * /rover/joint_right_wheel_velocity_controller/joint: joint_right_wheel
 * /rover/joint_right_wheel_velocity_controller/pid/d: 50
 * /rover/joint_right_wheel_velocity_controller/pid/i: 10
 * /rover/joint_right_wheel_velocity_controller/pid/p: 1000
 * /rover/joint_right_wheel_velocity_controller/type: effort_controller...
 * /rover/joint_state_controller/publish_rate: 60
 * /rover/joint_state_controller/type: joint_state_contr...
 * /rover/robot_description: <?xml version="1....

NODES
  /rover/
    controller_spawner (controller_manager/spawner)
    m2wr_spawn (gazebo_ros/spawn_model)

ROS_MASTER_URI=http://localhost:11311

process[rover/m2wr_spawn-1]: started with pid [22037]
process[rover/controller_spawner-2]: started with pid [22038]
[INFO] [1608147460.849910, 0.000000]: Controller Spawner: Waiting for service controller_manager/load_controller
[INFO] [1608147460.881118, 0.000000]: Controller Spawner: Waiting for service controller_manager/switch_controller
[INFO] [1608147460.905153, 11720.939000]: Controller Spawner: Waiting for service controller_manager/unload_controller
[INFO] [1608147460.919619, 11720.944000]: Loading controller: joint_state_controller
[INFO] [1608147460.951871, 11720.959000]: Loading controller: joint_left_wheel_velocity_controller
[ERROR] [1608147461.983806, 11721.560000]: Failed to load joint_left_wheel_velocity_controller
[INFO] [1608147461.988456, 11721.566000]: Loading controller: joint_right_wheel_velocity_controller
[ERROR] [1608147463.008570, 11722.090000]: Failed to load joint_right_wheel_velocity_controller
[INFO] [1608147463.013640, 11722.093000]: Controller Spawner: Loaded controllers: joint_state_controller
[INFO] [1608147463.036750, 11722.102000]: Started controllers: joint_state_controller
[INFO] [1608147464.088454, 0.000000]: Loading model XML from ros parameter robot_description
[INFO] [1608147464.170536, 0.000000]: Waiting for service /gazebo/spawn_urdf_model
[INFO] [1608147464.197719, 11722.766000]: Calling service /gazebo/spawn_urdf_model
[INFO] [1608147464.229827, 11722.781000]: Spawn status: SpawnModel: Failure - entity already exists.

Ros control is installed, thus I am bit confused on why I get this error. Could you please help?

URDF file:

<?xml version="1.0" ?>
<robot name="rover" xmlns:xacro="http://www.ros.org/wiki/xacro">
  <material name="black">
    <color rgba="0.0 0.0 0.0 1.0"/>
  </material>
  <material name="blue">
    <color rgba="0.203125 0.23828125 0.28515625 1.0"/>
  </material>
  <material name="green">
    <color rgba="0.0 0.8 0.0 1.0"/>
  </material>
  <material name="grey">
    <color rgba="0.2 0.2 0.2 1.0"/>
  </material>
  <material name="orange">
    <color rgba="1.0 0.423529411765 0.0392156862745 1.0"/>
  </material>
  <material name="brown">
    <color rgba="0.870588235294 0.811764705882 0.764705882353 1.0"/>
  </material>
  <material name="red">
    <color rgba="0.80078125 0.12890625 0.1328125 1.0"/>
  < ...

Hello,

I am trying to create a simple 4 wheel robot with a camera and I have written this code for the urdf model:

<robot name="labrob">
  <!-- Base link -->
  <link name="base_link">
    <visual>
      <origin xyz="0 0 0" rpy="0 0 0" />
      <geometry>
          <box size="1 0.5 0.25"/>
      </geometry>
      <material name="yellow">
        <color rgba="0.8 0.8 0 1"/>
      </material>
    </visual>
  </link>
  <!-- Front Right Wheel -->
  <link name="f_r_wheel">
    <visual>
      <origin xyz="0 0 0" rpy="1.570795 0 0" />
      <geometry>
          <cylinder length="0.1" radius="0.2" />
      </geometry>
      <material name="black">
        <color rgba="0.05 0.05 0.05 1"/>
      </material>
    </visual>
  </link>
  <joint name="joint_f_r_wheel" type="continuous">
    <parent link="base_link"/>
    <child link="f_r_wheel"/>
    <origin xyz="0.25 -0.30 0" rpy="0 0 0" /> 
    <axis xyz="0 1 0" rpy="0 0 0" />
  </joint>  
  <!-- Back Right Wheel -->
  <link name="b_r_wheel">
    <visual>
      <origin xyz="0 0 0" rpy="1.570795 0 0" />
      <geometry>
          <cylinder length="0.1" radius="0.2" />
      </geometry>
      <material name="black"/>
    </visual>
  </link>
  <joint name="joint_b_r_wheel" type="continuous">
    <parent link="base_link"/>
    <child link="b_r_wheel"/>
    <origin xyz="-0.25 -0.30 0" rpy="0 0 0" /> 
    <axis xyz="0 1 0" rpy="0 0 0" />
  </joint>  
  <!-- Front Left Wheel -->
  <link name="f_l_wheel">
    <visual>
      <origin xyz="0 0 0" rpy="1.570795 0 0" />
      <geometry>
          <cylinder length="0.1" radius="0.2" />
      </geometry>
      <material name="black"/>
    </visual>
  </link>
  <joint name="joint_f_l_wheel" type="continuous">
    <parent link="base_link"/>
    <child link="f_l_wheel"/>
    <origin xyz="0.25 0.30 0" rpy="0 0 0" /> 
    <axis xyz="0 1 0" rpy="0 0 0" />
  </joint>
  <!-- Back Left Wheel -->
  <link name="b_l_wheel">
    <visual>
      <origin xyz="0 0 0" rpy="1.570795 0 0" />
      <geometry>
          <cylinder length="0.1" radius="0.2" />
      </geometry>
      <material name="black"/>
    </visual>
  </link>
  <joint name="joint_b_l_wheel" type="continuous">
    <parent link="base_link"/>
    <child link="b_l_wheel"/>
    <origin xyz="-0.25 0.30 0" rpy="0 0 0" /> 
    <axis xyz="0 1 0" rpy="0 0 0" />
  </joint>


</robot>

As you can read I haven't put yet the camera or the trasmission blocks. I just have written the basic structure of the model with the joints. I have also written this .launch file:

<launch>
  <!-- urdf xml robot description loaded on the Parameter Server-->
  <param name="robot_description" textfile="$(find labrob_description)/urdf/labrob.urdf" />
  <arg name="gui" default="true" />
  <arg name="rvizconfig" default="$(find labrob_description)/rviz/urdf.rviz" />


  <!--param name="robot_description" command="$(find xacro)/xacro.py $(arg model)" -->
  <param name="use_gui" value="$(arg gui)"/>


  <!-- source that publishes the joint positions as a sensor_msgs/JointState -->
  <param name="use_gui" value="true"/>
  <node name="joint_state_publisher" pkg="joint_state_publisher" type="joint_state_publisher" />


  <!-- publish all the frames to TF -->
  <node pkg="robot_state_publisher" type="robot_state_publisher" name="rob_st_pub" >
  <param name="publish_frequency" value="50"/> <!-- Hz -->
  </node>


  <!-- robot visualization -->
  <node name="rviz" pkg="rviz" args="-d $(arg rvizconfig)" type="rviz" required="true" />
</launch>

In this launch file I am trying to display my model in the rviz environment. Via the launch file I call a .rviz configuration file which is this one:

Panels ...

Hello,

I am using ROS Kinetic and today I tried to create a package (labrob_control) to implement the necessary controllers for my actuators with the following dependencies: ros_control, ros_controllers.

I also checked at the /opt/ros/kinetic/share and I can see the 2 packages installed there.

But when I try to catkin_make my project I get the following warnings and errors:

Base path: /home/legged/4wheel_robot
Source space: /home/legged/4wheel_robot/src
Build space: /home/legged/4wheel_robot/build
Devel space: /home/legged/4wheel_robot/devel
Install space: /home/legged/4wheel_robot/install
####
#### Running command: "make cmake_check_build_system" in "/home/legged/4wheel_robot/build"
####
-- Using CATKIN_DEVEL_PREFIX: /home/legged/4wheel_robot/devel
-- Using CMAKE_PREFIX_PATH: /opt/ros/kinetic
-- This workspace overlays: /opt/ros/kinetic
-- Using PYTHON_EXECUTABLE: /usr/bin/python
-- Using Debian Python package layout
-- Using empy: /usr/bin/empy
-- Using CATKIN_ENABLE_TESTING: ON
-- Call enable_testing()
-- Using CATKIN_TEST_RESULTS_DIR: /home/legged/4wheel_robot/build/test_results
-- Found gtest sources under '/usr/src/gtest': gtests will be built
-- Using Python nosetests: /usr/bin/nosetests-2.7
-- catkin 0.7.1
-- BUILD_SHARED_LIBS is on
WARNING: package "labrob_control" should not depend on metapackage "ros_control" but on its packages instead
WARNING: package "labrob_control" should not depend on metapackage "ros_controllers" but on its packages instead
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- ~~  traversing 3 packages in topological order:
-- ~~  - labrob_control
-- ~~  - labrob_description
-- ~~  - labrob_gazebo
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- +++ processing catkin package: 'labrob_control'
-- ==> add_subdirectory(labrob/labrob_control)
CMake Warning at /opt/ros/kinetic/share/catkin/cmake/catkinConfig.cmake:76 (find_package):
  Could not find a package configuration file provided by "ros_control" with
  any of the following names:

    ros_controlConfig.cmake
    ros_control-config.cmake

  Add the installation prefix of "ros_control" to CMAKE_PREFIX_PATH or set
  "ros_control_DIR" to a directory containing one of the above files.  If
  "ros_control" provides a separate development package or SDK, be sure it
  has been installed.
Call Stack (most recent call first):
  labrob/labrob_control/CMakeLists.txt:7 (find_package)


-- Could not find the required component 'ros_control'. The following CMake error indicates that you either need to install the package with the same name or change your environment so that it can be found.
CMake Error at /opt/ros/kinetic/share/catkin/cmake/catkinConfig.cmake:83 (find_package):
  Could not find a package configuration file provided by "ros_control" with
  any of the following names:

    ros_controlConfig.cmake
    ros_control-config.cmake

  Add the installation prefix of "ros_control" to CMAKE_PREFIX_PATH or set
  "ros_control_DIR" to a directory containing one of the above files.  If
  "ros_control" provides a separate development package or SDK, be sure it
  has been installed.
Call Stack (most recent call first):
  labrob/labrob_control/CMakeLists.txt:7 (find_package)


-- Configuring incomplete, errors occurred!
See also "/home/legged/4wheel_robot/build/CMakeFiles/CMakeOutput.log".
See also "/home/legged/4wheel_robot/build/CMakeFiles/CMakeError.log".
Makefile:1704: recipe for target 'cmake_check_build_system' failed
make: *** [cmake_check_build_system] Error 1
Invoking "make cmake_check_build_system" failed

Maybe it's important to notice that the package labrob_control is under a metapackage called labrob, along with two other packages: labrob_description, labrob_gazebo. Could you please tell me what is wrong here?

I also tried in the packages directory the following command in case any dependency was missing:

rosdep install --from-paths . --ignore-src --rosdistro kinetic

but everything ... (more)

Hello,

I am new to ROS and I am using ROS Kinetic. So far I have found a URDF code for a hokuyo laser sensor, which I would like to use for simulations and I have put it on my robot:

 <link name="hokuyo_link">
    <collision>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <box size="0.15 0.15 0.15"/>
      </geometry>
    </collision>

    <visual>
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <geometry>
        <mesh filename="package://labrob_description/meshes/hokuyo.dae"/>
      </geometry>
    </visual>

    <inertial>
      <mass value="1e-5" />
      <origin xyz="0 0 0" rpy="0 0 0"/>
      <inertia ixx="1e-6" ixy="0" ixz="0" iyy="1e-6" iyz="0" izz="1e-6" />
    </inertial>
  </link>

  <property name="hokuyo_link" value="0.15" />
  <joint name="hokuyo_joint" type="fixed">
    <axis xyz="0 1 0" />
    <origin xyz="0.425 0 0.15" rpy="0 0 0"/>
    <parent link="base_link"/>
    <child link="hokuyo_link"/>
  </joint>

  <!-- hokuyo -->
  <gazebo reference="hokuyo_link">
    <sensor type="gpu_ray" name="head_hokuyo_sensor">
      <pose>0 0 0 0 0 0</pose>
      <visualize>false</visualize>
      <update_rate>40</update_rate>
      <ray>
        <scan>
          <horizontal>
            <samples>720</samples>
            <resolution>1</resolution>
            <min_angle>-1.570796</min_angle>
            <max_angle>1.570796</max_angle>
          </horizontal>
        </scan>
        <range>
          <min>0.10</min>
          <max>30.0</max>
          <resolution>0.01</resolution>
        </range>
        <noise>
          <type>gaussian</type>
          <!-- Noise parameters based on published spec for Hokuyo laser
               achieving "+-30mm" accuracy at range < 10m.  A mean of 0.0m and
               stddev of 0.01m will put 99.7% of samples within 0.03m of the true
               reading. -->
          <mean>0.0</mean>
          <stddev>0.01</stddev>
        </noise>
      </ray>
      <plugin name="gazebo_ros_head_hokuyo_controller" filename="libgazebo_ros_gpu_laser.so">
        <topicName>/labrob/laser/scan</topicName>
        <frameName>hokuyo_link</frameName>
      </plugin>
    </sensor>
  </gazebo>

I can successfully roslaunch the robot with the sensor in gazebo and see that the /labrob/laser/scan topic is being used from the sensor. I have tried adding objects really close to the sensor (tables for example), but I get the same data as when the sensor is in an empty world. The data which are being published on the topic are the following:

header: 
  seq: 37775
  stamp: 
    secs: 1156
    nsecs: 736000000
  frame_id: hokuyo_link
angle_min: -1.57079994678
angle_max: 1.57079994678
angle_increment: 0.00436940183863
time_increment: 0.0
scan_time: 0.0
range_min: 0.10000000149
range_max: 30.0
ranges: [-inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf, -inf ...