0
$\begingroup$

I'm trying to setup a ur10 robot in Moveit with a conveyor belt next to it. Unfortunately the move_group node as well as the servo node print out the following warning:

The complete state of the robot is not yet known. Missing BeltPrismatic.

here are my urdfs:

this is the Urdf I primarily start:

<?xml version="1.0"?>
<robot xmlns:xacro="http://wiki.ros.org/xacro" name="$(arg name)">
    <!-- robot name parameter -->
    <xacro:arg name="name" default="ur"/>
    <!-- import main macro -->
    <xacro:include filename="$(find ur_description)/urdf/ur_macro.xacro"/>

    <!-- possible 'ur_type' values: ur3, ur3e, ur5, ur5e, ur10, ur10e, ur16e -->
    <!-- the default value should raise an error in case this was called without defining the type -->
    <xacro:arg name="ur_type" default="ur10"/>

    <!-- parameters -->
    <xacro:arg name="tf_prefix" default="" />
    <xacro:arg name="joint_limit_params" default="$(find ur_description)/config/$(arg ur_type)/joint_limits.yaml"/>
    <xacro:arg name="kinematics_params" default="$(find ur_description)/config/$(arg ur_type)/default_kinematics.yaml"/>
    <xacro:arg name="physical_params" default="$(find ur_description)/config/$(arg ur_type)/physical_parameters.yaml"/>
    <xacro:arg name="visual_params" default="$(find ur_description)/config/$(arg ur_type)/visual_parameters.yaml"/>
    <xacro:arg name="transmission_hw_interface" default=""/>
    <xacro:arg name="safety_limits" default="false"/>
    <xacro:arg name="safety_pos_margin" default="0.15"/>
    <xacro:arg name="safety_k_position" default="20"/>
    <xacro:arg name="simulation_controllers" default="joint_trajectory_controller" />

    <!-- initial position for simulations (Fake Hardware, Gazebo, Ignition) -->
    <xacro:arg name="initial_positions_file" default="$(find ur_description)/config/initial_positions.yaml"/>

    <!-- convert to property to use substitution in function -->
    <xacro:property name="initial_positions_file" default="$(arg initial_positions_file)"/>

    <!-- create link fixed to the "world" -->
    <link name="world" />
    <!-- 
         After #52 this will be less verbose 
         since read_model_data will be seperate from ur_robot
         and we can modify just the properties we need
     -->
    <xacro:property name="jnt_limits_file" value="$(arg joint_limit_params)"/>
    <xacro:property name="jnt_limits"
      value="${xacro.load_yaml(jnt_limits_file)['joint_limits']}"
    />
    <xacro:property name="fric_scale" value="100.0" />  
    <xacro:property name="joint_dyn_dict"
      value="${dict(
          joint_dynamics=dict(
              shoulder_pan_joint=dict(damping=0.0, friction=fric_scale*jnt_limits['shoulder_pan_joint']['max_effort']),
              shoulder_lift_joint=dict(damping=0.0, friction=fric_scale*jnt_limits['shoulder_lift_joint']['max_effort']),
              elbow_joint=dict(damping=0.0, friction=fric_scale*jnt_limits['elbow_joint']['max_effort']),
              wrist_1_joint=dict(damping=0.0, friction=fric_scale*jnt_limits['wrist_1_joint']['max_effort']),
              wrist_2_joint=dict(damping=0.0, friction=fric_scale*jnt_limits['wrist_2_joint']['max_effort']),
              wrist_3_joint=dict(damping=0.0, friction=fric_scale*jnt_limits['wrist_3_joint']['max_effort'])))}"
    />
    <param name="blah" value="${joint_dyn_dict}" />
    
    
    <!-- arm -->
    
    <xacro:ur_robot
      name="$(arg name)"
      tf_prefix="$(arg tf_prefix)"
      parent="world"
      safety_limits="$(arg safety_limits)"
      safety_pos_margin="$(arg safety_pos_margin)"
      safety_k_position="$(arg safety_k_position)"
      joint_limits_parameters_file="$(arg joint_limit_params)"
      kinematics_parameters_file="$(arg kinematics_params)"
      physical_parameters_file="$(arg physical_params)"
      visual_parameters_file="$(arg visual_params)"
      joint_dynamics="${joint_dyn_dict}"
      transmission_hw_interface=""
      sim_gazebo="true"
      initial_positions="${xacro.load_yaml(initial_positions_file)}"
      >
      <origin xyz="0 0 0.05" rpy="0 0 0" />  
    </xacro:ur_robot>
 
    <!--//////////////////////////////////MODIFIKATIONEN AB HIER///////////////////////////////-->

    <xacro:include filename="$(find camera_sim)/description/camera_sim.xacro"/>
    <joint name="camera_ur_mount" type="fixed">
      <origin xyz="0 -0.02 0.0025" rpy="0 0 0"/>
      <parent link="wrist_3_link"/>
      <child link="camera_mount_link"/>
    </joint>

    <xacro:include filename="$(find gripper)/description/gripperV2.xacro"/>
    <joint name="toolmount" type="fixed">
      <origin xyz="0 0 0.035" rpy="0 0 1.57"/>
      <parent link="wrist_3_link"/>
      <child link="connector_link"/>
    </joint>  

    <xacro:include filename="$(find belt)/description/belt.urdf.xacro"/>
    <joint name="belt_mount" type="fixed">
      <origin xyz="1 0 0.3" rpy="0 0 0"/>
      <parent link="world"/>
      <child link="belt"/>
    </joint>


  <!--//////////////////////////////////ENDE MODIFIKATIONEN///////////////////////////////-->
    

    <!-- Gazebo plugins -->
    <gazebo reference="world">
    </gazebo>
    <gazebo>
      <plugin filename="libgazebo_ros2_control.so" name="gazebo_ros2_control">
        <parameters>$(arg simulation_controllers)</parameters>
      </plugin>
    </gazebo>

</robot>

and this is the Urdf of the belt:

<?xml version="1.0"?>

<!--///////////////////////////AUFBAU DES FÖRDERBANDES///////////////////////////////////-->

<!--link name="root_link"/>
<joint name="root_joint" type="fixed">
    <origin xyz="1 0 0.035" rpy="0 0 0"/>
    <parent link="root_link"/>
    <child link="belt"/>
</joint-->

<link name="belt">
    <visual>
        <origin xyz="0.1 0 0.08" rpy="0 0 0" />
        <geometry>
            <box size="1 3 0.15" />
        </geometry>
        <material name="belt">
            <color rgba="0.3 0.3 0.3 1" />
        </material>
    </visual>
    <inertial>
        <origin xyz="0.4 0 0.08" rpy="0 0 0" />
        <mass value="0.5"/>
        <inertia ixx="0.01" ixy="0.0" ixz="0.0" iyy="0.01" iyz="0.0" izz="0.01"/>
    </inertial>

    <collision>
        <origin xyz="0.4 0 0.08" rpy="0 0 0" />
        <geometry>
            <box size="1 3 0.15" />
        </geometry>
    </collision>
</link>


<link name="cube">
    <visual>
        <origin xyz="0 -1 0.2" rpy="0 0 0" />
        <geometry>
            <box size="0.1 0.1 0.1" />
        </geometry>
        <material name="belt">
            <color rgba="0.5 1.0 0.5 1" />
        </material>
    </visual>
    <inertial>
        <origin xyz="0 -1 0.15" rpy="0 0 0" />
        <mass value="0.5"/>
        <inertia ixx="0.01" ixy="0.0" ixz="0.0" iyy="0.01" iyz="0.0" izz="0.01"/>
    </inertial>
    <collision>
        <origin xyz="0 -1 0.15" rpy="0 0 0" />
        <geometry>
            <box size="0.1 0.1 0.1" />
        </geometry>
    </collision>
</link>


<!--joint name="cube_mount" type="fixed">
    <origin xyz="1 0 0.035" rpy="0 0 1.57"/>
    <parent link="belt"/>
    <child link="cube"/>
</joint-->


<joint name="BeltPrismatic" type="prismatic">
    <origin rpy="0 0 0" xyz="0.1 0 0.01"/> 
    <parent link="belt"/>
    <child link="cube"/>
    <axis xyz="0 1 0"/> 
    <limit lower="-0.75" upper="0.75" effort="100" velocity="10.0"/> 
</joint>


<!--////////////////////////////////////////Gazebo-Eigenschaften///////////////////////////////////////////-->
 <gazebo reference="belt">
    <material>Gazebo/DarkGrey</material>
</gazebo>
<gazebo reference="cube">
    <material>Gazebo/Grey</material>
</gazebo>

If you need more code/other files to help me out just ask. Im happy to provide them.

Improve this question
$\endgroup$

1 Answer 1

Reset to default
1
$\begingroup$

It is most likely that the robot and the conveyor are on different tf trees. From what I understand, you have two separate objects in your world, who are not aware of the transformation between them. You can verify this using the view_frames node of the tf2_tools package.

What you can also try out is to edit (a copy of) the UR10 URDF file to manually include the conveyor belt as an extra link there. Then it would be easier for you to integrate it into the overall MoveIt framework.

From what it looks like, you have specified to MoveIt that you have a prismatic joint somewhere in your kinematic chain called BeltPrismatic, my guess is that somewhere in the SRDF file. Now MoveIt expects to know the state of this BeltPrismatic joint, which it most likely cannot find because of the tf trees being different. Try and add it as a part of the same robot, and see if that solves your issue.

Improve this answer
$\endgroup$
1
  • 1
    $\begingroup$ found the error, didn't specify the joints in my controllers.yaml properly $\endgroup$
    – Icon45
    Commented Aug 13, 2023 at 15:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.