Missing world fixed frame
I'm using ROS Noetic and I have built a custom world with AR Tags and a robot. When I try to obtain the robot yaw in order to calculate the position in global coordinates, the tf package just answer world is not a frame. I've tried to implement a joint between base_link and world but an error is presented showing "world" is not defined. I have read that world is a preset of gazebo but it seems to not be defined. Thank you.
<?xml version="1.0" ?> <robot
name="ERC22_URDF"
xmlns:xacro="http://www.ros.org/wiki/xacro">
<xacro:include filename="$(find
ERC22_URDF_description)/urdf/materials.xacro"
/> <xacro:include filename="$(find
ERC22_URDF_description)/urdf/ERC22_URDF.trans"
/> <xacro:include filename="$(find
ERC22_URDF_description)/urdf/ERC22_URDF.gazebo"
/>
<link name="base_link"> <inertial>
<origin xyz="0.009312479330910419 0.0008928693179026247 0.4508429285266153" rpy="0 0 0"/>
<mass value="1.729680238629788"/>
<inertia ixx="0.122469" iyy="0.093078" izz="0.197526"
ixy="-5.1e-05" iyz="1.2e-05"
ixz="0.006038"/> </inertial>
<visual>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<mesh filename="package://ERC22_URDF_description/meshes/base_link.stl"
scale="0.001 0.001 0.001"/>
</geometry>
<material name="silver"/> </visual> <collision>
<origin xyz="0 0 0" rpy="0 0 0"/>
<geometry>
<mesh filename="package://ERC22_URDF_description/meshes/base_link.stl"
scale="0.001 0.001 0.001"/>
</geometry> </collision> </link>
<link name="WLF_supp_1"> <inertial>
<origin xyz="-0.0005722202916380592
0.04456811672884131 -0.06998013314667545" rpy="0 0 0"/>
<mass value="0.040963207008450755"/>
<inertia ixx="0.000114" iyy="9.6e-05" izz="3e-05" ixy="-0.0"
iyz="1.6e-05" ixz="-1e-06"/>
</inertial> <visual>
<origin xyz="-0.391355 0.383158 -0.356565" rpy="0 0 0"/>
<geometry>
<mesh filename="package://ERC22_URDF_description/meshes/WLF_supp_1.stl"
scale="0.001 0.001 0.001"/>
</geometry>
<material name="silver"/> </visual> <collision>
<origin xyz="-0.391355 0.383158 -0.356565" rpy="0 0 0"/>
<geometry>
<mesh filename="package://ERC22_URDF_description/meshes/WLF_supp_1.stl"
scale="0.001 0.001 0.001"/>
</geometry> </collision> </link>
<link name="Left_leg_double_1">
<inertial>
<origin xyz="-0.017610729784847123 -0.06278452284012215 -0.07487224121996011" rpy="0 0 0"/>
<mass value="0.1583068780205665"/>
<inertia ixx="0.00075" iyy="0.003257" izz="0.002638"
ixy="-0.000164" iyz="-3.5e-05"
ixz="0.000733"/> </inertial>
<visual>
<origin xyz="0.252653 0.310658 -0.453036" rpy="0 0 0"/>
<geometry>
<mesh filename="package://ERC22_URDF_description/meshes/Left_leg_double_1.stl"
scale="0.001 0.001 0.001"/>
</geometry>
<material name="silver"/> </visual> <collision>
<origin xyz="0.252653 0.310658 -0.453036" rpy="0 0 0"/>
<geometry>
<mesh filename="package://ERC22_URDF_description/meshes/Left_leg_double_1.stl"
scale="0.001 0.001 0.001"/>
</geometry> </collision> </link>
<link name="WLB_supp_1"> <inertial>
<origin xyz="0.0011204573839502796 0.031881968364872504 -0.06607317272822505" rpy="0 0 0"/>
<mass value="0 ...
Please explain at a high level what information you are trying to obtain. The
/tf
topic may not be the right place to find it. Can you provide a link to your simulation files (e.g. github or a zip file)?