I want to use a conveyor belt in my gazebo simulation.
I found this project which includes a conveyor belt. Now I'm trying to make this model and adapt it to my needs. I mainly want to make the whole thing a lot bigger. Since I'm not very good in CAD and I don't care about the optics, I thought it might be better to replace the mesh that was used in that project with a simple box. So I replaced the mesh with a box and adapted the dimensions to my need. Then I saved the model. The resulting sdf-file looks like this:
<?xml version='1.0'?>
<sdf version='1.7'>
<model name='conveyor_belt_simplified'>
<link name='belt_visual'>
<pose>0 0 0.05 0 -0 0</pose>
<inertial>
<pose>0 0 0.1 0 -0 0</pose>
<mass>71.953</mass>
<inertia>
<ixx>7.5972</ixx>
<ixy>0</ixy>
<ixz>0</ixz>
<iyy>0.99673</iyy>
<iyz>0</iyz>
<izz>8.1168</izz>
</inertia>
</inertial>
<self_collide>0</self_collide>
<enable_wind>0</enable_wind>
<kinematic>0</kinematic>
<gravity>1</gravity>
<visual name='belt_visual_visual'>
<pose>0 0 0.1 0 -0 0</pose>
<geometry>
<box>
<size>1 10 0.25</size>
</box>
</geometry>
<material>
<shader type='pixel'>
<normal_map>__default__</normal_map>
</shader>
<script>
<name>ModelPreview_1::belt_visual::belt_visual_visual_MATERIAL_</name>
<uri>__default__</uri>
</script>
<ambient>0 0 0 1</ambient>
<diffuse>0 0 0 1</diffuse>
<specular>0 0 0 1</specular>
<emissive>0 0 0 1</emissive>
</material>
<transparency>0</transparency>
<cast_shadows>1</cast_shadows>
</visual>
<collision name='belt_visual_collision'>
<laser_retro>0</laser_retro>
<max_contacts>10</max_contacts>
<pose>0 0 0.1 1.5708 -0 1.5708</pose>
<geometry>
<box>
<size>10 0.25 1</size>
</box>
</geometry>
<surface>
<friction>
<ode>
<mu>1</mu>
<mu2>1</mu2>
<fdir1>0 0 0</fdir1>
<slip1>0</slip1>
<slip2>0</slip2>
</ode>
<torsional>
<coefficient>1</coefficient>
<patch_radius>0</patch_radius>
<surface_radius>0</surface_radius>
<use_patch_radius>1</use_patch_radius>
<ode>
<slip>0</slip>
</ode>
</torsional>
</friction>
<bounce>
<restitution_coefficient>0</restitution_coefficient>
<threshold>1e+06</threshold>
</bounce>
<contact>
<collide_without_contact>0</collide_without_contact>
<collide_without_contact_bitmask>1</collide_without_contact_bitmask>
<collide_bitmask>1</collide_bitmask>
<ode>
<soft_cfm>0</soft_cfm>
<soft_erp>0.2</soft_erp>
<kp>1e+13</kp>
<kd>1</kd>
<max_vel>0.01</max_vel>
<min_depth>0</min_depth>
</ode>
<bullet>
<split_impulse>1</split_impulse>
<split_impulse_penetration_threshold>-0.01</split_impulse_penetration_threshold>
<soft_cfm>0</soft_cfm>
<soft_erp>0.2</soft_erp>
<kp>1e+13</kp>
<kd>1</kd>
</bullet>
</contact>
</surface>
</collision>
</link>
<link name='belt_moving'>
<pose>0 0 0.2 0 -0 0</pose>
<inertial>
<pose>0 0 0.1 0 -0 0</pose>
<mass>100</mass>
<inertia>
<ixx>0</ixx>
<ixy>0</ixy>
<ixz>0</ixz>
<iyy>0</iyy>
<iyz>0</iyz>
<izz>0</izz>
</inertia>
</inertial>
<self_collide>0</self_collide>
<enable_wind>0</enable_wind>
<kinematic>0</kinematic>
<gravity>1</gravity>
<collision name='belt_moving_collision'>
<laser_retro>0</laser_retro>
<max_contacts>10</max_contacts>
<pose>0 0 0.1 0 -0 0</pose>
<geometry>
<box>
<size>1 10 0.001</size>
</box>
</geometry>
<surface>
<friction>
<ode>
<mu>1</mu>
<mu2>1</mu2>
<fdir1>0 0 0</fdir1>
<slip1>0</slip1>
<slip2>0</slip2>
</ode>
<torsional>
<coefficient>1</coefficient>
<patch_radius>0</patch_radius>
<surface_radius>0</surface_radius>
<use_patch_radius>1</use_patch_radius>
<ode>
<slip>0</slip>
</ode>
</torsional>
</friction>
<bounce>
<restitution_coefficient>0</restitution_coefficient>
<threshold>1e+06</threshold>
</bounce>
<contact>
<collide_without_contact>0</collide_without_contact>
<collide_without_contact_bitmask>1</collide_without_contact_bitmask>
<collide_bitmask>1</collide_bitmask>
<ode>
<soft_cfm>0</soft_cfm>
<soft_erp>0.2</soft_erp>
<kp>1e+13</kp>
<kd>1</kd>
<max_vel>0.01</max_vel>
<min_depth>0</min_depth>
</ode>
<bullet>
<split_impulse>1</split_impulse>
<split_impulse_penetration_threshold>-0.01</split_impulse_penetration_threshold>
<soft_cfm>0</soft_cfm>
<soft_erp>0.2</soft_erp>
<kp>1e+13</kp>
<kd>1</kd>
</bullet>
</contact>
</surface>
</collision>
</link>
<joint name='belt_joint' type='prismatic'>
<parent>belt_visual</parent>
<child>belt_moving</child>
<pose>0 0 0 0 -0 0</pose>
<axis>
<xyz>0 1 0</xyz>
<limit>
<lower>0</lower>
<upper>1</upper>
<effort>1000</effort>
<velocity>1000</velocity>
</limit>
<dynamics>
<spring_reference>0</spring_reference>
<spring_stiffness>0</spring_stiffness>
<damping>0</damping>
<friction>0</friction>
</dynamics>
</axis>
<physics>
<ode>
<limit>
<cfm>0</cfm>
<erp>0.2</erp>
</limit>
<suspension>
<cfm>0</cfm>
<erp>0.2</erp>
</suspension>
</ode>
</physics>
</joint>
<static>0</static>
<allow_auto_disable>1</allow_auto_disable>
<plugin name='conveyor_belt_plugin' filename='libROSConveyorBeltPlugin.so'>
<robot_namespace>/</robot_namespace>
<link>belt_moving</link>
<power>0</power>
<max_velocity>1.0</max_velocity>
<robotNamespace>/conveyor/</robotNamespace>
</plugin>
</model>
</sdf>
Now I wanted to test my simplified conveyor belt model. So I just edited the launch file of the project (which can be found here) to use my new model instead of theirs. I.e. I changed the line
<node name="spawn_model_belt" pkg="gazebo_ros" type="spawn_model" args="-file $(find demo_world)/urdf/conveyor.urdf -urdf -model conveyor_belt" respawn="false" output="screen" />
to
<node name="spawn_model_belt" pkg="gazebo_ros" type="spawn_model" args="-file /home/max/model_editor_models/conveyor_belt_simplified/model.sdf -sdf -model conveyor_belt_simplified" respawn="false" output="screen" />
Now when I launch this, it kind of works, but not really. The edited conveyor belt is spawned and also the little boxes that are spawned by a ROS node of the project work normal. The only problem is, that my conveyor belt model is spawned at an entirely differen location far away from the origin. I have no idea why this happens, since I only adapted the dimensions of the object but not it's location. Can anyone tell me what I'm doing wrong here or how to spawn it at the origin of the world?
