ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | ros @ Robotics Stack Exchange
Ask Your Question

Westranger's profile - activity

2020-06-22 11:37:27 -0500 received badge  Great Question (source)
2019-08-23 05:40:54 -0500 received badge  Famous Question (source)
2019-06-27 07:52:45 -0500 marked best answer Velocity controll and PID tuneing

I'm currently building a simulation model for my robot and so far almost every thing works. I can move all my actuators. I'm currently stuck with the controlling the wheel velocity.

I have a joint

   <joint name="wheel_main_rotation" type="continuous">
      <parent link="wheel_main_suspension" />
      <child link="wheel_main" />
      <origin xyz="0 0 -0.1" rpy="0 0 0" />
      <axis xyz="0 1 0" />
      <limit effort="2000.0" velocity="1.0" />
   </joint>

with a transmission

   <transmission name="tran2">
      <type>transmission_interface/SimpleTransmission</type>
      <joint name="wheel_main_rotation">
         <hardwareInterface>hardware_interface/EffortJointInterface</hardwareInterface>
      </joint>
      <actuator name="motor2">
         <hardwareInterface>hardware_interface/EffortJointInterface</hardwareInterface>
         <mechanicalReduction>1</mechanicalReduction>
      </actuator>
   </transmission>

with the following controller config

  # velocity Controllers ---------------------------------------
  joint2_velocity_controller:
    type: effort_controllers/JointVelocityController
    joint: wheel_main_rotation
    pid: {p: 10000.0, i: 1.0, d: 1000.0}

and a rosnode which publishes the value 1.0 on the following topic

pub = rospy.Publisher('/my_robot_ns/joint2_velocity_controller/command', Float64, queue_size=10)

This approach works for all my revoloute and prismatic joints, but not for controlling the velocity of the main wheel. I actually doesn't move at all, no matter which value I publish.

edit:

the maximum velocity of my robot should be 1.0 m/sec

2019-06-27 07:52:45 -0500 received badge  Self-Learner (source)
2019-03-05 12:22:38 -0500 received badge  Notable Question (source)
2019-01-30 09:12:10 -0500 marked best answer rviz dows not display model (urdf tutorial)

I have just installed ROS lunar on Ubuntu 17.04. I wanted to start with the urdf tutorial and tried to display the second model (02-multipleshapes.urdf) but rviz does not display the model. I do see the RobotModel Entry on the left side in the TreeView, the links are also there. But in the 3D view in the center I can only see an 3D axis with not mesh.

image description

edit:

rosparam get /robot_description

outputs

"<?xml version=\"1.0\" ?>\n<!-- ===================================================================================\
  \ -->\n<!-- |    This document was autogenerated by xacro from /home/secret-path-to-my-workspace/urdf/01-myfirst.urdf\
  \ | -->\n<!-- |    EDITING THIS FILE BY HAND IS NOT RECOMMENDED                \
  \                 | -->\n<!-- ===================================================================================\
  \ -->\n<robot name=\"myfirst\">\n  <link name=\"base_link\">\n    <visual>\n   \
  \   <geometry>\n        <cylinder length=\"0.6\" radius=\"0.2\"/>\n      </geometry>\n\
  \    </visual>\n    <collision>\n      <geometry>\n        <cylinder length=\"0.6\"\
  \ radius=\"0.2\"/>\n      </geometry>\n    </collision>\n  </link>\n</robot>\n\n

which is actually the the same urdf file like in the tutorial (except for the collision part)

2018-12-21 07:23:52 -0500 received badge  Taxonomist
2018-11-02 02:00:07 -0500 received badge  Notable Question (source)
2018-11-02 02:00:07 -0500 received badge  Famous Question (source)
2018-11-02 02:00:07 -0500 received badge  Popular Question (source)
2018-09-19 11:04:50 -0500 received badge  Nice Question (source)
2018-08-10 08:39:16 -0500 marked best answer LaserScanner in Gazebo does not publish data while topic is set

I'm trying to add two laser scanners to my robot model, which work already. So I can see the rays in Gazebo. Like in the hokuyo example I also specified the topic on which the laser should publish its data but when I inspect the available topics the onces I specified are not there/visible. I guess I'm missing somthing like a gazebo-ros-laser connector but I don't get what I'm missing here.

I have the following gazebo tag in urdf/xarco file

   <gazebo reference="sick_lrf_back">
      <sensor name="laser_back" type="ray">
         <pose>0.5 0.0 0.0 0.0 0.0 0.0</pose>
         <always_on>1</always_on>
         <update_rate>10</update_rate>
         <visualize>true</visualize>
         <ray>
            <scan>
               <horizontal>
                  <samples>761</samples>
                  <resolution>1</resolution>
                  <min_angle>-1.6580627</min_angle>
                  <max_angle>1.6580627</max_angle>
               </horizontal>
            </scan>
            <range>
               <min>0.02</min>
               <max>49</max>
               <resolution>0.03</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="laser_back" filename="libRayPlugin.so">
            <!-- Publish within the robot namespace -->
            <robotNamespace>my_robot</robotNamespace>
            <topicName>laser_back/scan</topicName>
         </plugin>
      </sensor>
   </gazebo>
2018-08-10 08:39:16 -0500 received badge  Teacher (source)
2018-08-10 08:39:16 -0500 received badge  Self-Learner (source)
2018-07-09 17:00:19 -0500 received badge  Famous Question (source)
2018-05-23 00:39:18 -0500 received badge  Famous Question (source)
2018-05-16 11:03:18 -0500 received badge  Good Question (source)
2018-05-10 20:00:34 -0500 received badge  Famous Question (source)
2018-05-03 15:03:30 -0500 received badge  Famous Question (source)
2018-04-20 14:06:49 -0500 received badge  Nice Question (source)
2018-04-18 17:13:03 -0500 received badge  Famous Question (source)
2018-04-18 17:13:03 -0500 received badge  Notable Question (source)
2018-04-12 13:08:40 -0500 received badge  Notable Question (source)
2018-04-12 13:08:40 -0500 received badge  Famous Question (source)
2018-04-12 13:08:40 -0500 received badge  Popular Question (source)
2018-04-11 15:18:42 -0500 received badge  Popular Question (source)
2018-03-08 11:17:55 -0500 received badge  Notable Question (source)
2018-03-08 11:17:55 -0500 received badge  Famous Question (source)
2018-03-08 11:17:55 -0500 received badge  Popular Question (source)
2018-02-13 08:24:52 -0500 asked a question getting SIGSEGV when executing rosrun gazebo_ros gazebo

getting SIGSEGV when executing rosrun gazebo_ros gazebo I recently switched from Ubuntu 17.04 to 17.10 and now after ins

2018-02-09 13:15:58 -0500 received badge  Notable Question (source)
2018-02-09 13:15:58 -0500 received badge  Famous Question (source)
2018-02-09 13:15:58 -0500 received badge  Popular Question (source)
2018-01-12 06:29:22 -0500 received badge  Notable Question (source)
2018-01-02 09:24:57 -0500 marked best answer How to share common lib's in ROS workspace

I'm having several packages in my workspace and I'm currently at the point where a want to avoid code duplicity. At the moment I have package called myproject_common in which all msg and srv files are located. After building the workspace they are properly available in all my other packages. Now I want to my common .py files into the common packages and also make them available. After calling catkin_make the msg and srv classes are available under ./devel/lib/python2.7/dist-packages/ which is quiet nice because this makes them also available in my IDE without the need to import something manually. How can I accomplish this with self written common python files? What do I need to change in my CMakeLists.txt to get this working

edit:

I separated the msg / srv from the common modules, because the msg / srv stuff work fine so now my pkg with the shared modules is named myproject_common_lib

this is my directory structure

myproject_common_lib
├── CMakeLists.txt
├── package.xml
├── setup.py
└── src
    └── myproject_common_lib
        ├── coordinate.py
        ├── coordinate.pyc
        └── __init__.py

2 directories, 6 files

The content of my __init__.py looks like this

from coordinate import Coordinate

The content of my setup.py

## ! DO NOT MANUALLY INVOKE THIS setup.py, USE CATKIN INSTEAD

from distutils.core import setup
from catkin_pkg.python_setup import generate_distutils_setup

# fetch values from package.xml
setup_args = generate_distutils_setup(
    packages=['myproject_common_lib'],
    package_dir={'': 'src'},
)

setup(**setup_args)

The content of my CMakeLists.txt

cmake_minimum_required(VERSION 2.8.3)
project(myproject_common_lib)

find_package(catkin REQUIRED COMPONENTS
  rospy
)

catkin_python_setup()

catkin_package()

include_directories(
   $(catkin_INCLUDE_DIRS)
)

When I want to import the shared module I use the following import (which does not work)

from myproject_common_lib.coordinate import Coordinate

The content of my devel folder looks like this (short version)

devel
├── lib
│   └── python2.7
│       └── dist-packages
│           └── myproject_common_lib
│               ├── __init__.py
│               └── __init__.pyc
└── share
    ├── myproject_common_lib
    │   └── cmake
    │       ├── myproject_common_libConfig.cmake
    │       └── myproject_common_libConfig-version.cmake

I cannot see any difference to the posted tutorial. Also when watching this video I cannot see any difference :-(

edit 2:

This is what PyCharm sees

image description

2017-12-20 02:52:23 -0500 received badge  Notable Question (source)
2017-12-07 04:39:52 -0500 received badge  Popular Question (source)
2017-12-01 10:02:33 -0500 received badge  Student (source)
2017-11-29 08:49:58 -0500 edited question add_rostest_gtest(...) not finding GTest libs

add_rostest_gtest(...) not finding GTest libs I have a rostest which cannot be built with catkin_make. In my CMakeLists.