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2018-05-29 09:59:26 -0500 commented question Is it possible to decrease the ground_plane size ?

What if you put a 100x100 cuboid on top of ground_plane? Then the robot would fall off.

2018-05-29 09:16:19 -0500 edited question Grasping unable to lift object

Problem with simple grasping simulation Grasping is not working in this primitive case I've made. The object is a box o

2018-05-21 09:16:28 -0500 commented question Grasping unable to lift object

Thanks, @josephcoombe. The thing I don't understand about that scenario is that the joint forces seem high enough to li

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2018-05-16 15:20:40 -0500 edited question Grasping unable to lift object

Problem with simple grasping simulation Grasping is not working in this primitive case I've made. The object is a box o

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2018-05-16 13:39:18 -0500 edited question Grasping unable to lift object

Problem with simple grasping simulation Edit Do you think this strange behavior could be from using Gazeb 9 with the lat

2018-05-16 11:39:19 -0500 edited question Grasping unable to lift object

Problem with simple grasping simulation Grasping is not working in this primitive case I've made. The object is a box o

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2018-05-16 08:26:59 -0500 edited question Grasping unable to lift object

Problem with simple grasping simulation Grasping is not working in this primitive case I've made with Gazebo 9 and ROS K

2018-05-16 08:19:40 -0500 asked a question Grasping unable to lift object

Problem with simple grasping simulation Grasping is not working in this primitive case I've made with Gazebo 9 and ROS K

2018-05-14 10:59:27 -0500 commented answer Friction insufficient in grasping simulation

Using libgazebo_ros_ft_sensor.so I acquired force data during grasping. I changed back to EffortJointController and the

2018-05-14 10:58:47 -0500 commented answer Friction insufficient in grasping simulation

Using libgazebo_ros_ft_sensor.so I acquired force data during grasping. I changed back to EffortJointController and the

2018-05-14 10:57:30 -0500 commented answer Friction insufficient in grasping simulation

Using libgazebo_ros_ft_sensor.so I acquired force data during grasping and it's 1 kN on each of the two gripper joints.

2018-05-14 10:19:20 -0500 edited question Friction insufficient in grasping simulation

Friction insufficient in grasping simulation Update 2 Following some advice below I changed the ROS controller from Eff

2018-05-14 10:14:54 -0500 edited question Friction insufficient in grasping simulation

Friction insufficient in grasping simulation Update 2 Following some advice below I changed the ROS controller from Eff

2018-05-14 10:11:58 -0500 commented question Friction insufficient in grasping simulation

Thanks for your input. Yes, the gripper parts have inertial values. I cleared all the collision properties I'd set (mu

2018-05-11 16:18:06 -0500 commented answer Friction insufficient in grasping simulation

I think you're right; today I had just a few minutes to work and changed to a PositionJointInterface for the gripper joi

2018-05-10 15:28:20 -0500 commented answer Friction insufficient in grasping simulation

Thanks for that info. Alas the behavior is the same. Just watching the contacts, the green lines seem to jump around a

2018-05-10 15:27:08 -0500 commented answer Friction insufficient in grasping simulation

Thanks for that info. Alas the behavior is the same. Just watching the contacts they seem to jump around a lot: someti

2018-05-10 14:01:38 -0500 edited question Friction insufficient in grasping simulation

Friction insufficient in grasping simulation For an application where a manipulator picks up a cylinder I have created a

2018-05-10 12:57:47 -0500 edited question Friction insufficient in grasping simulation

Friction insufficient in grasping simulation For an application where a manipulator picks up a cylinder I have created a

2018-05-10 12:05:58 -0500 edited question Friction insufficient in grasping simulation

Friction insufficient in grasping simulation For an application where a manipulator picks up a cylinder I have created a

2018-05-10 10:08:44 -0500 edited question Friction insufficient in grasping simulation

Friction insufficient in grasping simulation For an application where a manipulator picks up a cylinder I have created a

2018-05-10 09:52:20 -0500 commented answer Friction insufficient in grasping simulation

Regarding a visualization of the contacts, they are identical to the visuals. By the way, where did your 1--100 range c

2018-05-10 09:49:48 -0500 commented answer What are the SDF Damping Units?

Whence did this info come?

2018-05-10 09:49:18 -0500 marked best answer What are the SDF Damping Units?

Here's the description of SDF joint --> axis --> dynamics --> damping, "The physical velocity dependent viscous damping coefficient of the joint." Can you tell me what units this number is interpreted as having.

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2018-05-10 09:28:03 -0500 commented answer Friction insufficient in grasping simulation

It looks like you were right that without the "reference" attribute the gazebo tag was not doing anything: I converted f

2018-05-10 09:12:42 -0500 commented answer Friction insufficient in grasping simulation

To the cylinder sdf I added a contact sensor and printed the contact values while it was being gripped. The resulting f

2018-05-10 08:45:56 -0500 commented answer Friction insufficient in grasping simulation

The question is updated to reflect your suggestions. The simulation behavior is unchanged, as far as I can tell.

2018-05-10 08:40:41 -0500 edited question Friction insufficient in grasping simulation

Friction insufficient in grasping simulation For an application where a manipulator picks up a cylinder I have created a

2018-05-10 08:22:33 -0500 commented answer Friction insufficient in grasping simulation

On my list of things to do today was add a reference attribute to the gazebo tag but it's my understanding that without

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2018-05-09 21:23:22 -0500 commented answer Friction insufficient in grasping simulation

Thanks for your response. I will update the friction coefficients and the other parameters tomorrow then let you know w

2018-05-09 21:22:04 -0500 commented answer Friction insufficient in grasping simulation

Thanks for your response. I will update the friction coefficients and the other parameters tomorrow. If you tell me ho

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2018-05-09 14:07:48 -0500 edited question Friction insufficient in grasping simulation

Friction insufficient for grasping simulation For an application where a manipulator picks up a cylinder I have created

2018-05-09 14:05:50 -0500 asked a question Friction insufficient in grasping simulation

Friction insufficient for grasping simulation For an application where a manipulator picks up a cylinder I have created

2018-04-19 08:46:50 -0500 commented answer Stack of two models unstable bouncing

Setting max_vel to 0 made no change but using 0.001 as the min_depth distance fixed the problem :)

2018-04-19 08:46:10 -0500 marked best answer Stack of two models unstable bouncing

Greetings. When I stack two one-link models (each is just a hollow cylinder, like a roll of paper towels) they keep colliding and bouncing until the top one finally gets thrown off. The STL is available here. The sdf and world files are pasted below. The animated gif shows the behavior. At the end of the gif, Gazebo show the collision and inertial elements. The inertial element is a bit off-center; I don't see why that would cause this but thought I should mention it. Can you help me get a stable stack of these models?

This is in Gazebo 9. In model.sdf I changed the restitution_coefficient tag from 0 to 0.5 in a failed attempt to resolve the issue (even though 0 should be the less bouncy value).

image description

Model sdf:

<sdf version='1.6'>
  <model name='Neleski_Cone_full'>
<link name='Neleski_Cone_full'>
  <pose>0 0 0 0 0 0</pose>
  <inertial>
        <pose>0.15 -0.15 0.14605 0 0 0</pose>
        <mass>130.96</mass>
        <inertia>
          <ixx>1.61005</ixx>
          <ixy>5.1652e-33</ixy>
          <ixz>5.85205e-33</ixz>
          <iyy>1.61005</iyy>
          <iyz>5.04266e-17</iyz>
          <izz>1.35779</izz>
        </inertia>
  </inertial>
  <collision name='Neleski_Cone_full_collision'>
    <surface>
      <bounce>
    <restitution_coefficient>0.5</restitution_coefficient>
      </bounce>
    </surface>
        <pose>0 0 0 1.5708 0 0</pose>
        <geometry>
          <mesh>
    <scale>.001 .001 .001</scale>
    <uri>model://Full_Cone/meshes/Neleski_Cone_full.STL</uri>
          </mesh>
        </geometry>
  </collision>
  <visual name='Neleski_Cone_full_visual'>
        <pose>0 0 0 1.5708 0 0</pose>
        <geometry>
          <mesh>
    <scale>.001 .001 .001</scale>
    <uri>model://Full_Cone/meshes/Neleski_Cone_full.STL</uri>
          </mesh>
        </geometry>
  </visual>
</link>
  </model>
</sdf>

World:

<sdf version='1.5'>
  <world name='default'>
<!-- A global light source -->
<include>
  <uri>model://sun</uri>
</include>
<!-- A ground plane -->
<include>
  <uri>model://ground_plane</uri>
</include>

<model name='Neleski_Cone_full_1'>
  <include>
    <static>0</static>
    <uri>model://Full_Cone</uri>
    <pose>-1 0 0.1 0 0 0</pose>
  </include>
</model>

<model name='Neleski_Cone_full_2'>
  <include>
    <static>0</static>
    <uri>model://Full_Cone</uri>
    <pose>-1 0 0.5 0 0 0</pose>
  </include>
</model>
  </world>
</sdf>
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2018-04-18 08:40:21 -0500 edited question Stack of two models unstable bouncing

Stack of two models unstable bouncing Greetings. When I stack two one-link models (each is just a hollow cylinder, like

2018-04-18 08:38:09 -0500 commented question Stack of two models unstable bouncing

Thanks. I added a link to the STL file. Regarding the use of a cylinder primitive, I'd already considered that and dec