Gazebo | Ignition | Community
Ask Your Question

K. Zeng's profile - activity

2020-12-18 13:14:07 -0500 marked best answer Stopping a Robot Through Friction?

So right now I'm trying to set up the friction of the ground plane (relevant parameters are mu and mu2) so that a 4-wheeled robot (SDF format, no friction mu values set for any links) will come to a stop after rolling down a slope. The software I'm using is Gazebo 2.22 along with ROS Indigo. I'm using the default version of the ground plane as below, with different values of mu and mu2:

<?xml version="1.0" ?>
<sdf version="1.5">
  <model name="ground_plane">
    <static>true</static>
    <link name="link">
      <collision name="collision">
        <geometry>
          <plane>
            <normal>0 0 1</normal>
            <size>100 100</size>
          </plane>
        </geometry>
        <surface>
          <friction>
            <ode>
              <mu>100</mu>
              <mu2>50</mu2>
            </ode>
          </friction>
        </surface>
      </collision>
      <visual name="visual">
        <cast_shadows>false</cast_shadows>
        <geometry>
          <plane>
            <normal>0 0 1</normal>
            <size>100 100</size>
          </plane>
        </geometry>
        <material>
          <script>
            <uri>file://media/materials/scripts/gazebo.material</uri>
            <name>Gazebo/Grey</name>
          </script>
        </material>
      </visual>
    </link>
  </model>
</sdf>

Now, there were no problems with the robot actually going down the hill, but I did notice that even with the ground plane's mu and mu2 set to maximum (100, 100), the model went at a (slow) constant velocity with no signs of stopping after coming down the hill. I'm trying to avoid setting the mu and mu2 values for the model itself, but are there other parameters that I need to adjust so the robot can actually come to a stop after rolling down the hill? Any help would be greatly appreciated.

2017-10-13 04:52:28 -0500 received badge  Good Question (source)
2017-08-22 04:47:03 -0500 received badge  Famous Question (source)
2017-08-22 04:47:03 -0500 received badge  Notable Question (source)
2017-08-22 04:47:03 -0500 received badge  Popular Question (source)
2016-02-18 18:12:42 -0500 received badge  Famous Question (source)
2016-02-18 18:12:42 -0500 received badge  Popular Question (source)
2016-02-18 18:12:42 -0500 received badge  Notable Question (source)
2016-02-08 07:49:21 -0500 received badge  Famous Question (source)
2016-01-04 06:55:59 -0500 received badge  Notable Question (source)
2016-01-04 06:55:59 -0500 received badge  Famous Question (source)
2016-01-04 06:55:59 -0500 received badge  Popular Question (source)
2015-10-31 12:30:37 -0500 marked best answer Simulating Aquatic Environments

I'm trying to create a simple beach environment for Gazebo. Is there a way for me to simulate shallow water? I just want to robot to drive down the "sand" and look like it's partially submerged in water.

2015-10-31 12:30:37 -0500 marked best answer Debug Messages in Gazebo 4?

I have a robot model that worked on Gazebo 2.2.3 on a different computer that I've been trying to port over to Gazebo 4. I copied the entire folder over to Gazebo 4's model directory and changed the SDF tags to 1.5 for both .sdf and .config files. For some reason, whenever I try to spawn the robot in Gazebo 4 through the menu, gzclient just terminates and gives me a generic "process has died" message. Is there somekind of debug model in Gazebo 4 that will allow me to determine what exactly is wrong with my model or Gazebo? I'm going to ask another question related to the Robot.

2015-10-31 12:30:35 -0500 marked best answer Call gazebo/set_model_state without resetting position

I asked this over at ROS forums as well, but I'm in a bit of a rush in this situation. Hi, everyone. I'm currently trying to use gazebo/set_ model_state in a C++ program to set a robot's velocity. My preliminary code is below:

 #include "ros/ros.h"
#include <gazebo_msgs/SetModelState.h>
#include <cstdlib>
//I'm going to implement user-specified twist values later.
int main (int argc, char **argv)
{
  ros::init(argc,argv,"robot_mover_mark_two");
  ros::NodeHandle n;
  ros::ServiceClient client = n.serviceClient<gazebo_msgs::SetModelState>("/gazebo/set_model_state");
  gazebo_msgs::SetModelState setmodelstate;
  gazebo_msgs::ModelState modelstate;
  modelstate.model_name = "my_robot";
  modelstate.reference_frame = "world";

  geometry_msgs::Twist model_twist;
  model_twist.linear.x = 1.0;
  model_twist.linear.y = 1.0;
  model_twist.linear.z = 0.0;
  model_twist.angular.x = 0.25;
  model_twist.angular.y = 0.0;
  model_twist.angular.z = 0.0;
  modelstate.twist = model_twist;

  setmodelstate.request.model_state = modelstate;

  if (client.call(setmodelstate))
  {
    ROS_INFO("BRILLIANT!!!");
    ROS_INFO("%f, %f",modelstate.pose.position.x,modelstate.pose.position.y);
  }  
  else
  {
    ROS_ERROR("Failed to call service ");
    return 1;
  }
  return 0;  
}

I noticed that every time I run the command, the robot's position is reset to the origin in the Gazebo simulation environment. Are the position parameters set to zero by default if I don't include them in the rosservice call? If so, are there any ways I can use this code and have the model stay in the current position (i.e. just change velocity/twist on the fly)?

2015-10-31 12:30:25 -0500 marked best answer Downgrade from Gazebo 4

I'm trying to downgrade from Gazebo 4 to Gazebo 3 and make it work with ROS Indigo. I'm using the following steps:

sudo sh -c 'echo "deb http://packages.osrfoundation.org/gazebo/ubuntu `lsb_release -cs` main" > /etc/apt/sources.list.d/gazebo-latest.list'
wget http://packages.osrfoundation.org/gazebo.key -O - | sudo apt-key add -
sudo apt-get update
sudo apt-get install ros-$distro-gazebo4-ros-pkgs

The problem is that I get the message "E: Unable to locate package ros-indigo-gazebo3-ros-pkgs". What am I doing wrong in the steps I'm using?

UPDATE: Does the package ros-indigo-gazebo3-ros-pkgs actually exist?

2015-10-31 12:30:17 -0500 marked best answer Create Vehicle with Suspension?

Is it possible to create a vehicle model in Gazebo (preferably versions 2 or 3) with a suspension system?

2015-10-31 12:30:13 -0500 marked best answer Set joint rotation range?

Hi everyone, I was wondering if there is a way to specify minimum and maximum angles of rotation for a joint? I want part of my robot to be partially articulated but the specific function shouldn't rotate the full 360 degrees.

2015-10-31 12:29:50 -0500 marked best answer Robot That Worked in Gazebo 2 Fails to Launch in Gazebo 4

Related to this question (http://answers.gazebosim.org/question...). I have a robot that previously worked in Gazebo 2 on a different computer that I've been trying to port over to Gazebo 4. For some reason, every time I try to click on the name of the model under the "Insert" tab, Gazebo just exits without any errors or warnings. It was not like this for some of my simpler models or the models that were provided by default in the Gazebo model database. I've checked over the .sdf and .config files but can't find anything wrong with it. I've attached the .sdf file below just in case anyone is interested.
model.sdf

Here is the code for the .config file:

<?xml version="1.0"?>
<model>
  <name>Mesh Robot</name>
  <version>1.0</version>
  <sdf version="1.5">model.sdf</sdf>
  <author>
    <name>John Doe</name>
    <email>john.doe@example.com</email>
  </author>
  <description>
    Insert description here.
  </description>
</model>

The only changes I made after downloading the files onto the computer with Gazebo 4 was that I changed <sdf> version tags from 1.4 to 1.5. The meshes referenced are saved exactly in the folder I wanted. I honesly have no clue what else to do at this point. Any help would be greatly appreciated, thanks.

UPDATE: When I ran Gazebo in verbose mode, I got the following warning.

[Wrn] [ColladaLoader.cc:1361] Polylist input semantic: 'COLOR' is currentlynot supported
2015-10-31 12:12:36 -0500 marked best answer Confusion Regarding Gazebo 4 and ROS Installation

I have been trying to install Gazebo 4 along with ROS Indigo in the following method:

    1. Install ros-indigo-desktop-full
    2. Run sudo apt-get remove gazebo-* (I realized that it also removes ROS)
    3. Following along the source installation instructions for Gazebo 4 on this page (http://gazebosim.org/tutorials?tut=install), which resulted in a problem related to this question (http://answers.gazebosim.org/question/7224/gazebo-4-installation-fails-on-make-j4/)

Is there something I'm doing wrong? An answer I got from a different question here (http://answers.gazebosim.org/question/7008/gazebo-4-installation-help/) yielded a different way to install Gazebo 4 along side ROS Indigo. Am I supposed to just do a desktop install and not a full install? Or would the Gazebo 4 packages automatically override the Gazebo 2 ones that came with Indigo?

2015-10-31 12:12:01 -0500 marked best answer Altering Scene.cc to Change Grid Size

This is a follow-up question to an earlier one I asked regarding changing grid size. Is there any way to access the Scene.cc file so I can change the hard-coded value of 20x20? I tried to use ls in the directory it's stored in, but all it showed were the .hh files.

2015-10-31 12:11:58 -0500 marked best answer Gazebo 4 Installation Help

I'm trying to install Gazebo 4.0 on a different computer alongside ROS Indigo. I already removed Gazebo 2.2.2 that came with ROS. I saw on the tutorial page that in order to make Gazebo 4 work with ROS, I need to first "Add the osrfoundation repository to your sources list.". Does anyone know exactly what that step entails (i.e. what terminal commands to run)? Thanks.

2015-10-31 12:05:55 -0500 marked best answer Using SDF 1.5 with Gazebo 2.22

Currently, I'm trying to use the world files found in here: https://bitbucket.org/osrf/gazebo/com...atlasdemo.world". However, I noticed they are all in SDF 1.5. Can SDF 1.5 be used with Gazebo 2.22?

2015-09-01 02:00:14 -0500 received badge  Famous Question (source)
2015-09-01 01:34:35 -0500 received badge  Famous Question (source)
2015-08-26 18:26:47 -0500 received badge  Popular Question (source)
2015-06-25 12:00:34 -0500 received badge  Famous Question (source)
2015-06-22 05:08:37 -0500 marked best answer Increase Ground Plane Grid Size

Hello everyone, I know that you can adjust the size of the ground plane itself, but is there a way to change the size of the gridded area so it's bigger than 20x20? Thanks.

2015-06-22 04:32:35 -0500 received badge  Nice Question (source)
2015-05-16 22:30:03 -0500 received badge  Popular Question (source)
2015-05-16 22:30:03 -0500 received badge  Notable Question (source)
2015-05-16 22:30:03 -0500 received badge  Famous Question (source)
2015-04-20 07:20:36 -0500 received badge  Famous Question (source)
2015-04-12 21:50:32 -0500 received badge  Nice Question (source)
2015-04-12 20:26:13 -0500 received badge  Popular Question (source)
2015-04-12 20:26:13 -0500 received badge  Notable Question (source)
2015-04-09 14:01:50 -0500 received badge  Nice Question (source)
2015-04-09 14:01:42 -0500 received badge  Famous Question (source)
2015-04-09 00:54:12 -0500 received badge  Famous Question (source)
2015-04-09 00:54:12 -0500 received badge  Popular Question (source)
2015-04-09 00:54:12 -0500 received badge  Notable Question (source)
2015-03-03 21:37:58 -0500 received badge  Notable Question (source)