Gazebo

Gazebo

The nice sim framework Gazebo from here http://gazebosim.org/ can now be use from withing Paparazzi. Are you doing work on UAS in combination with e.g. Vision based navigation check it out. I might make testing your new work so much simpler.

Be warned, using it can be highly addictive, and might tempt youinto buying a new computer with hight spacification. To be able to use Gaxzebo a very good Video card is needed, considder upgrading you yadware if everything runs to slow.

Installation and use take alook here http://docs.paparazziuav.org/v5.12/module__fdm_gazebo.html

Gazebo backend for NPS NPS simulator

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Installation

We assume you already have Paparazzi installed via the One liner. If Not install Paparzzi first plz. Then come back to this page.

Gazebo Installation=

Steps to install Gazebo

     1. Make sure gazebo 9 is installed. (sudo apt-get install gazebo8 libgazebo8-dev)

Model

Prepare your Gazebo aircraft model (example see conf/simulator/gazebo/models/ardrone/):

Place the aircraft model in the conf/simulator/gazebo/models/ folder, this folder is added to the search path of Gazebo when NPS is launched. Gazebo uses a Front, Left, Up coordinate system for aircraft, so make sure the +x axis points forwards. The model should include a link for each motor with the same names as those listed in NPS_ACTUATOR_NAMES (see below), e.g. 'nw_motor'. Camera links should have the name specified in .dev_name in the

corresponding video_config_t struct, see sw/airborne/boards/pc_sim.h and sw/airborne/modules/computer_vision/video_thread_nps.c.

World

Prepare the world (see conf/simulator/gazebo/worlds/ardrone.world).

NOTE: Pay attention to the following:

The real-time update rate should be set to zero, as the simulation backend is already handled by Paparazzi:

<physics type="ode">
<max_step_size>0.001</max_step_size>
<real_time_update_rate>0</real_time_update_rate><!-- Handled by Paparazzi! -->
</physics>

Spherical coordinates should be provided for navigation. At this moment, there is an issue where Gazebo incorrectly uses a WSU coordinate system instead of ENU. This can be fixed by setting the heading to 180 degrees as shown below:

<spherical_coordinates>
<surface_model>EARTH_WGS84</surface_model>
<latitude_deg>51.9906</latitude_deg>
<longitude_deg>4.37679</longitude_deg>
<elevation>0</elevation>
<heading_deg>180</heading_deg><!-- Temporary fix for issue https://bitbucket.org/osrf/gazebo/issues/2022/default-sphericalcoordinates-frame-should -->
</spherical_coordinates>

Airframe

Prepare the airframe file (see examples/ardrone2_gazebo.xml):

        a) Select Gazebo as the FDM (Flight Dynamics Model)
             <target name="nps" board="pc">
           <module name="fdm" type="gazebo"/>
         </target>

    b) Add actuator thrusts and torques to the SIMULATOR section:
         <section name="SIMULATOR" prefix="NPS_">
           <define name="ACTUATOR_NAMES" value="nw_motor, ne_motor, se_motor, sw_motor" type="string[]"/>
           <define name="ACTUATOR_THRUSTS" value="1.55, 1.55, 1.55, 1.55" type="double[]"/>
           <define name="ACTUATOR_TORQUES" value="0.155, -0.155, 0.155, -0.155" type="double[]"/>
           ...
         <section>
       The thrusts and torques are expressed in SI units (N, Nm) and should
       be in the same order as the ACTUATOR_NAMES.

    c) In the same section, bypass the AHRS and INS as these are not
       supported yet:
         <section name="SIMULATOR" prefix="NPS_">
           ...
           <define name="BYPASS_AHRS" value="1"/>
         <define name="BYPASS_INS" value="1"/>
           ...
         <section>
    d) If required, enable video thread simulation:
         <section name="SIMULATOR" prefix="NPS_">
           ...
           <define name="SIMULATE_VIDEO" value="1"/>
           ...
         <section>
    e) If required, specify the Gazebo world and aircraft name:
         <section name="SIMULATOR" prefix="NPS_">
           ...
           <define name="GAZEBO_WORLD" value="my_world.world"/>
           <define name="GAZEBO_AC_NAME" value="my_uav"/>
         <section>
   4. Make sure all included modules work with nps. At the moment, most of
      the modules that depend on video_thread are only built when ap is
      selected as the target. As a quick fix, try to remove the target
      attribute from the makefile element in the module xml, e.g.:
        <makefile target="ap"> ---> <makefile> 

Reality

Never forget... A sim is not reality... validate via testflights in the real world after you think everything you created works perfectly.