RebeccaK375's profile - activity

Dear all,

I am trying to create a working conveyor belt in Gazebo. I built a conveyor in SolidWorks and used the Solidworks to URDF Exporter to generate the URDF file.

The belt appears in Gazebo just fine, but I cannot get it to actually move when effort is applied to a Cylinder.

Image of Conveyor Belt in Question:

I think the problem is my definition of links and joints in the Solidworks to URDF Exporter (and the URDF file that is generated).

Here us the URDF File:

<robot
  name="Belt1_BeltLink_2Joints_Velocity_Effort_1Joint">
  <link
    name="belt_link">
    <inertial>
      <origin
        xyz="0.6096 2.7377E-15 -3.81"
        rpy="0 0 0" />
      <mass
        value="44.292" />
      <inertia
        ixx="273.86"
        ixy="4.3225E-28"
        ixz="5.8096E-16"
        iyy="273.75"
        iyz="1.1641E-14"
        izz="7.7268" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://Belt1_BeltLink_2Joints_Velocity_Effort_1Joint/meshes/belt_link.STL" />
      </geometry>
      <material
        name="">
        <color
          rgba="0.79216 0.81961 0.93333 1" />
      </material>
    </visual>
    <collision>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://Belt1_BeltLink_2Joints_Velocity_Effort_1Joint/meshes/belt_link.STL" />
      </geometry>
    </collision>
  </link>
    <gazebo reference="belt_link">
      <material>Gazebo/FlatBlack</material>
    </gazebo>
  <link
    name="cylinder1_link">
    <inertial>
      <origin
        xyz="0.0013099 -0.6096 -6.1529E-18"
        rpy="0 0 0" />
      <mass
        value="767.9" />
      <inertia
        ixx="114.77"
        ixy="4.9176E-15"
        ixz="-1.3005E-17"
        iyy="39.109"
        iyz="6.0768E-31"
        izz="114.58" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://Belt1_BeltLink_2Joints_Velocity_Effort_1Joint/meshes/cylinder1_link.STL" />
      </geometry>
      <material
        name="">
        <color
          rgba="0.79216 0.81961 0.93333 1" />
      </material>
    </visual>
    <collision>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://Belt1_BeltLink_2Joints_Velocity_Effort_1Joint/meshes/cylinder1_link.STL" />
      </geometry>
    </collision>
  </link>
  <joint
    name="cylinder1_joint"
    type="continuous">
    <origin
      xyz="0 0 0"
      rpy="1.5708 -1.5708 0" />
    <parent
      link="belt_link" />
    <child
      link="cylinder1_link" />
    <axis
      xyz="0 1 0" />
    <limit
      effort="10"
      velocity="5" />
  </joint>
  <link
    name="cylinder2_link">
    <inertial>
      <origin
        xyz="0.0013099 -0.6096 0"
        rpy="0 0 0" />
      <mass
        value="767.9" />
      <inertia
        ixx="114.77"
        ixy="4.8695E-15"
        ixz="-6.0881E-16"
        iyy="39.109"
        iyz="5.158E-31"
        izz="114.58" />
    </inertial>
    <visual>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://Belt1_BeltLink_2Joints_Velocity_Effort_1Joint/meshes/cylinder2_link.STL" />
      </geometry>
      <material
        name="">
        <color
          rgba="0.79216 0.81961 0.93333 1" />
      </material>
    </visual>
    <collision>
      <origin
        xyz="0 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://Belt1_BeltLink_2Joints_Velocity_Effort_1Joint/meshes/cylinder2_link.STL" />
      </geometry>
    </collision>
  </link>
  <joint
    name="cylinder2_joint"
    type="continuous">
    <origin
      xyz="0 7.62 0"
      rpy="1.5708 -1.5708 0" />
    <parent
      link="belt_link" />
    <child
      link="cylinder2_link" />
    <axis
      xyz="0 1 0" />
  </joint>
</robot>

Does anyone know how I would define joints and links in SW to URDF Exporter/ URDF in order for the belt to move when torque is applied on one of the cylinders?

I also tried applying joint effort using this:

rosservice call gazebo/apply_joint_effort '{joint_name: cylinder2_joint, effort: 10, start_time: 10000000000, duration: 1000000000}'

Thank you for your help!

Hello Everyone!

I am trying to create a conveyor belt simulation in gazebo, using the SolidWorks to URDF exporter. Before importing the conveyor, I decided to test the exporter out on a simple part, and I managed to spawn it in Gazebo just fine, but no matter what I do, I cannot seem to get any color but white/gray.

Tried the following: Changing texture in URDF Exporter, changing the RGB values in URDF file, changing colors and textures in SolidWorks before exporting.

Am I doing something wrong?

Thank you for your time!

Example URDF generated from a extruded pink cube in solidworks. (not edited)

<robot
  name="Part1">
  <link
    name="PinkCube">
    <inertial>
      <origin
        xyz="0.127 0.127 0.127"
        rpy="0 0 0" />
      <mass
        value="16.387" />
      <inertia
        ixx="0.176204636837333"
        ixy="5.11592420833947E-18"
        ixz="6.07865277557629E-18"
        iyy="1.07890658921981E-17"
        iyz="-0.176204636837333"
        izz="1.07890658921981E-17" />
    </inertial>
    <visual>
      <origin
        xyz="1.5707963267949 0 0"
        rpy="0 0 0" />
      <geometry>
        <mesh
          filename="package://PinkCube/meshes/PinkCube.STL" />
      </geometry>
      <material
        name="">
        <color
          rgba="0.79216 0.81961 0.93333 1" />
      </material>
    </visual>
    <collision>
      <origin
        xyz="0 0 0"
        rpy="1.5707963267949 0 0" />
      <geometry>
        <mesh
          filename="package://PinkCube/meshes/PinkCube.STL" />
      </geometry>
    </collision>
  </link>
</robot>

Thank you! It does give me a more clear picture!

Hey all,

My goal is to have a robot output its current movement and let LEDs know when to flash, indicating that the care-o-robot is moving. I will be connecting a new LED through a USB port on the robot, but first I want to get this working in a Gazebo simulator.

The way I see it (and I may be wrong), I will need to do the following:

1) Create a node that listens to robot's base 2) Have that node output "on" or "off" to the LED connected through a USB

I am new to ROS and a little overwhelmed by the amount of tutorials. I am not sure where to look for relevant information...

Are there any tutorials that are specifically dedicated to creating new nodes for a robot? How to make that node communicate with another node on the robot?

How to define that node as the Digital Output for the LED?

I read through the general node tutorials, but when I dig through Care-o-Bot files, I find files far more complex than in the tutorial.

I know this is a lot of questions, but if you could give some advice on at least one of them, I would be very thankful! General advise is appreciated as well!

Dear all,

I need to model a robot that has either a projector or LEDs on board that light up at certain times, and I am having a hard time getting started. Are there any tutorials as to how to model a component that was added to the robot and have it act based off robot's output? If you have any suggestions, I would highly appreciate them!

Thank you!

Hey all,

I was wondering if someone could explain how friction works in Gazebo. I noticed that for robots like PR2, friction properties are defined for joints rather than for links.

How can I define friction properties for the object itself and not for a specific joint between two objects?

Let's say I have a belt and I define friction between a belt and some other object in URDF. I can add this to the joint:

<dynamics friction="100.0" />
<mu1 value="0.7" />
<mu2 value="0.7" />

However, if I want the belt and any object that I potentially import/drive on it to have friction between them, how do I do it?

Thank you!

Thank you! For now, the fix suggested by Benjamin does the trick.

Thank you for responding! I just added information to my question above, showing pieces of URDF file. I did have the friction and damping component in the joints, but it did not help.