Multi-Vehicle Simulation Error

[gy2256]

Hello,

I am following the guide on multi-vehicle simulation: https://dev.px4.io/en/simulation/multi-vehicle-simulation.html.

But I got an error when I run roslaunch px4 multi_uav_mavros_sitl.launch

The error is the following:

Done checking log file disk usage. Usage is <1GB.
Usage: xacro.py [options] <input>

xacro.py: error: expected exactly one input file as argument
while processing /home/burobotics/Guang/src/Firmware/launch/single_vehcile_spawn.launch:
Invalid <param> tag: Cannot load command parameter [iris_1_sdf]: command [/opt/ros/kinetic/share/xacro/xacro.py /home/burobotics/Guang/src/Firmware/Tools/sitl_gazebo/models/rotors_description/urdf/iris_base.xacro rotors_description_dir:=/home/burobotics/Guang/src/Firmware/Tools/sitl_gazebo/models/rotors_description mavlink_udp_port:=14560 > iris_1.urdf ; 'gz sdf -p iris_1.urdf'] returned with code [2]. 

Param xml is <param command="$(arg cmd)" name="$(arg vehicle)_$(arg ID)_sdf"/>
The traceback for the exception was written to the log file

Note: when I run the single vehicle simulation everything works just fine. The mavros is also working and I can rostopic echo the sensor messages. I only have issues with the multi vehicle simulation.

[gy2256]

It looks like I cannot load iris_1_sdf in the single_vehcile_spawn.launch. Any idea how to fix that?

[gy2256]

OK. I am trying to write my own launch file.

<launch>

    <arg name="debug" default="false"/>
    <arg name="verbose" default="false"/>
    <arg name="paused" default="false"/>

    <arg name="est" default="lpe"/>
    <arg name="world" default="$(find mavlink_sitl_gazebo)/worlds/empty.world"/>

    <arg name="headless" default="false"/>
    <arg name="gui" default="true"/>

    <arg name="pluginlists_yaml" default="$(find mavros)/launch/px4_pluginlists.yaml" />
    <arg name="config_yaml" default="$(find mavros)/launch/px4_config.yaml" />

    <!-- Load world -->
  <include file="$(find gazebo_ros)/launch/empty_world.launch">
      <arg name="headless" value="$(arg headless)"/>
      <arg name="gui" value="$(arg gui)"/>
      <arg name="world_name" value="$(arg world)" />
      <arg name="debug" value="$(arg debug)" />
      <arg name="verbose" value="$(arg verbose)" />
      <arg name="paused" value="$(arg paused)" />
  </include>

  <!-- UAV1 iris_1-->
<group ns="uav1">
    <arg name="name" default="iris_1"/>
    <arg name="ns" default="/iris_1/"/>
    <arg name="fcu_url" default="udp://:14540@localhost:14557"/>
    <arg name="vehicle" default="iris_1"/>
    <arg name="rcS" default="$(find px4)/posix-configs/SITL/init/$(arg est)/$(arg vehicle)"/>
    <arg name="sdf" default="$(find mavlink_sitl_gazebo)/models/$(arg vehicle)/$(arg vehicle).sdf"/>
    <arg name="gcs_url" value=""/>

    <arg name="x" default="0"/>
    <arg name="y" default="0"/>
    <arg name="z" default="0"/>
    <arg name="R" default="0"/>
    <arg name="P" default="0"/>
    <arg name="Y" default="0"/>

    <node name="$(anon vehicle_spawn)" output="screen" pkg="gazebo_ros" type="spawn_model"
        args="-sdf -file $(arg sdf) -model $(arg name) -x $(arg x) -y $(arg y) -z $(arg z) -R $(arg R) -P $(arg P) -Y $(arg Y)"/>

    <node name="sitl" pkg="px4" type="px4" output="screen"
            args="$(find px4) $(arg rcS)">
    </node>

    <include file="$(find px4)/launch/mavros.launch">
        <arg name="ns" value="$(arg ns)"/>
        <arg name="gcs_url" value=""/> <!-- GCS link is provided by SITL -->
        <arg name="fcu_url" value="$(arg fcu_url)"/>
        <arg name="pluginlists_yaml" value="$(arg pluginlists_yaml)" />
        <arg name="config_yaml" value="$(arg config_yaml)" />
    </include>
</group>

</launch>

<!-- vim: set et ft=xml fenc=utf-8 ff=unix sts=0 sw=4 ts=4 : -->

But I got a new error:

[uav1/vehicle_spawn_xx_MS_7922_28787_8827596932026697940-4] process has died [pid 28851, exit code 1, cmd /opt/ros/kinetic/lib/gazebo_ros/spawn_model -sdf -file /home/xx/Firmware/Tools/sitl_gazebo/models/iris_1/iris_1.sdf -model iris_1 -x 0 -y 0 -z 0 -R 0 -P 0 -Y 0 __name:=vehicle_spawn_xx_MS_7922_28787_8827596932026697940 __log:=/home/xx/.ros/log/d44c0db6-67d9-11e7-9aba-4ccc6a27bd2a/uav1-vehicle_spawn_xx_MS_7922_28787_8827596932026697940-4.log].
log file: /home/xx/.ros/log/d44c0db6-67d9-11e7-9aba-4ccc6a27bd2a/uav1-vehicle_spawn_xx_MS_7922_28787_8827596932026697940-4*.log

[ChenYunan]

@gyang1011 Hello, I have the same ERROR as yours. Did you solve this error? Why did you close this issue?

[khris-kabbabe]

@gyang1011 Hi, I would like to know what you solution was. I followed the instructions but have not been able to get this working. Any help would be appreciated. EDIT: After further look into the issue, the problem, if that, seems to be with the single_vehcile_spawn.launch. If you run the command in line 16 on it's own (with the correct arguments) in the command line it will generate the required filed, then remove that line from the file and run the multi_uav_mavros_sitl.launch. That way it works for me.

[EdXian]

@khris-kabbabe Hi , i wonder know which line you removed in the file single_vehcile_spawn.launch Dose the file still work fine without "16 line" ? Thanks!!

[YCH188]

I found a solution,but haven't tried.Maybe it will help. https://github.com/PX4/sitl_gazebo/pull/101

[lamping7]

@YCH188 multi_uav_mavros_sitl.launch was fixed in https://github.com/PX4/Firmware/pull/8831 However, be aware that the dev guide needs updated

[hamishwillee]

@lamping7 What changes need to be made in the devguide? Is there a tracking PR/issue?

[lamping7]

https://github.com/PX4/Devguide/pull/461