hmmm's profile - activity

Hi guys, what does a negativ update rate in a .world file mean? i was told that the simulation then runs as far as possible in order to provide nearly realtime simulation.But i cant find a documentation or explanation in ros or ODE. Is that true? Where can i find a documentation about that?? <physics:ode> <steptime>0.001</steptime> <gravity>0 0 -9.8</gravity> <cfm>0.0000000001</cfm> <erp>0.2</erp> <quickstep>true</quickstep> <quickstepiters>10</quickstepiters> <quickstepw>1.3</quickstepw> <contactmaxcorrectingvel>100.0</contactmaxcorrectingvel> <contactsurfacelayer>0.001</contactsurfacelayer> <updaterate>-0.1</updaterate> </physics:ode>

hi guys, i want to publish from a gazebo plugin. How can i do that? In the same way as i publish from a common node? so do i have to write a main() and while{} and so on? I want to publish torque in order to plot it with rxplot. this is the part of the plugin:

torque.x = inertia.x *  controllers_.roll.update(roll_command, euler.x, angular_velocity.x, dt);
torque.y = inertia.y *  controllers_.pitch.update(pitch_command, euler.y, angular_velocity.y, dt);

body_->SetTorque(torque);

i try following, is this the right way?

ros::Publisher wrench_publisher;
geometry_msgs::Wrench moment;
int main(int argc, char **argv)
{
  ros::init(argc, argv, "hector_quadrotor_gazebo_plugins");
  ros::NodeHandle node_handle;
  ros::Rate loop_rate(100);
  wrench_publisher_ = node_handle.advertise<geometry_msgs::Wrench>("force", 1);
  while(ros::ok())
  {
  ros::spinOnce();
  moment.torque.x = torque.x ;
  moment.torque.y = torque.y;

  wrench_publisher.publish(moment);
  }
  return 0;
}

how can i subscribe to /gazebo/model_states ? Sorry, i am a beginner an did not understand it, yet.I read the tutorial but it does not help me.I want to get the x,y and z Position of my model. For beginning i write this.But how to go on ?

ros::Subscriber xyz_subscriber_;

void ModelStatecallback(const gazebo_msgs::ModelStates::ConstPtr& msg)
{


}

xyz_subscriber_ = node_handle_.subscribe</gazebo/model_states>("currentposition", 1, ModelStatecallback);

};

Hi guys , i would like to create a node for position control. It should get current position values and the target position values . For control i want to use a common PID Control for each coordinate.The node should output cmd_velocity message (geometry_msgs/Twist topic)

Is there maybe ready code for my goal? Can i write a simple publisherfor that goal? So it is possible that a common publisher communicate with a gazebo plugin? How the code might look like?

thanks adrian

hi,guys i would like to ask, which standard message i can use to control a quadrotor by a joystick/gamepad. I want the node to publish three angels and thrust.Is there a standard message i can use?

Hi guys, i cant find the definition of the constant M_PI ?

i try to understand following command : axes_yaw_max = 90.0*M_PI/180.0;

hi all,i need a modell of a barometer sensor in gazebo. is there any plugin ,i can use? how can i modell a barometric sensor? i need this for controlling the hight position of my quadrotor in gazebo.

thanks regards

from where does starmac simulated_quadrotor get its sensordata for simulation ??? are the sensors(acc,gyro,...) modelled in starmac simulator??? Is starmac a real simulation of a quadrokopter???? It is confusing because the simulated_quadrotor uses RVIZ.But Rviz is only a Vizualisation,as far as i understand.

I want a real Simulation of my selfmade quadrotor.How can i achieve this?

thanks,greets adrian

hi,guys i despair over an error message . i can not start rviz, and dont know why.i use ubuntu 10.04 rviz starts with ubuntu higher versions,but i don't like that.Want to use 10.04 so my graphic card is not guilty. where is the problem?any body here who can help me ? thanks,regards adrian

here the terminal output :

auto-starting new master process[master]: started with pid [16798] ROS_MASTER_URI=http://localhost:11311

setting /run_id to 1e62e032-4512-11e1-9e45-90004e158d56 process[rosout-1]: started with pid [16812] started core service [/rosout] process[robot_state_publisher-2]: started with pid [16824] process[rviz-3]: started with pid [16827] The program 'rviz' received an X Window System error. This probably reflects a bug in the program. The error was 'BadDrawable (invalid Pixmap or Window parameter)'. (Details: serial 22 error_code 9 request_code 136 minor_code 3) (Note to programmers: normally, X errors are reported asynchronously; that is, you will receive the error a while after causing it. To debug your program, run it with the --sync command line option to change this behavior. You can then get a meaningful backtrace from your debugger if you break on the gdk_x_error() function.) [rviz-3] process has died [pid 16827, exit code 1]. log files: /home/adrian/.ros/log/1e62e032-4512-11e1-9e45-90004e158d56/rviz-3*.log ^C[robot_state_publisher-2] killing on exit [rosout-1] killing on exit [master] killing on exit shutting down processing monitor... ... shutting down processing monitor complete done

hello,i would like to subscribe the hight information and the orientation information of the plugin,that is included within the urdf-file. here the included part :

  <controller:gazebo_ros_p3d name="quadro_groundtruth_sim" plugin="libgazebo_ros_p3d.so">
    <alwaysOn>true</alwaysOn>
    <updateRate>100.0</updateRate>
    <bodyName>imu_link</bodyName>
    <topicName>ground_truth_pose</topicName>
    <gaussianNoise>0.0</gaussianNoise>
    <frameName>map</frameName>
    <interface:position name="my_box_p3d_position_iface" />
  </controller:gazebo_ros_p3d>

how can i subscribe this hight information and the orientation information within a node? i tried following.But i don't know how to proceed.

#include "ros/ros.h"
#include "std_msgs/String.h"
#include "gazebo_ros_p3d.h"      // is that the header i have to include???

void chatterCallback(const std_msgs::String::ConstPtr& msg)
{
  ROS_INFO("I heard: [%s]", msg->data.c_str());
}

int main(int argc, char **argv)
{

  ros::init(argc, argv, "listener");      
  ros::NodeHandle n;
  ros::Subscriber sub = n.subscribe("ground_truth_pose", 1000, chatterCallback);

  ros::spin();

  return 0;
}

But where is my mistake? thanks,regards

hi guys, i need a height position control for a quadrocopter in gazebo. Is there any useable plugin to achieve this goal? I thought of an ultrasonic sensor plugin for gazebo that provides the height information. Any suggestions are welcome

thanks,greetz

hi guys, gazebo do not simulate air friction. So how can i modell this in gazebo? in order to simulate a quadrotor "relatively"realistic, i need to take air friction into account. So i thought whether it is possible to model air friction by an "against force" or rather by an "against torque" which are quadratically proportional to the linear velocity and angular velocity. Are there any plugins or written nodes or anything i can use to achieve this goal?? Any suggestion are welcome. how can i start generally? thanks regards

hi all, how can i modell a magnetic field sensor in Gazebo?? Can anybody please help me?

hi,all can anyone explain me please ,what the following content of that launchfile (from tutorial: http://www.ros.org/wiki/simulator_gazebo/Tutorial/SpawningObjectInSimulation means???

<launch>
  <!-- send table urdf to param server -->
  <param name="table_description" command="$(find xacro)/xacro.py $(find gazebo_worlds)/objects/table.urdf.xacro" />

  <!-- push table_description to factory and spawn robot in gazebo -->
  <node name="spawn_table" pkg="gazebo" type="spawn_model" args="-urdf -param table_description -z 0.01 -model table_model" respawn="false" output="screen" />
</launch>

the interesting part for me is : <node name="spawn_table" pkg="gazebo" type="spawn_model" args="-urdf -param table_description -z 0.01 -model table_model" <="" p="">

is spawn_table a (standard) node within the gazebo stack?But i cant find that node.i have searched for that within the simulator_gazebo stack. i only find the spawn_model node,under /opt/ros/electric/stacks/simulator_gazebo/gazebo/scripts question: what is spawn_table?

hello, is there also a opportunity to write private messages here to members?? if yes , how? i can`t find .

greets

hi all,i need to modell sensors like:gyro,acc,magnetfieldsensor in Gazebo. Are there any examples for a sensor implemented urdf-file? how can i modell these sensors in a urdf file,for my quadrotor?

thanks, greets

hi all, i want my quadrotor to fly autonomously. Are there any examples,what and how i can achieve this goal? Until now,my quadrotor does only handle the sensordate from IMU(acc,gyro,mag). IMU-->Kalmanfilter-->PID-Control -->IMU Are there any ROS solutions,which can be used?written node for sensordatafusion? Which sensors for autonomous indoor fliying. would you recommend?

thanks ,greets

hi guys, i want to plot the orientation of my quadrotor in euler and not in quaterion. is there a opportunity (message) how i can get the angels in euler from gazebo?

thankgs,regards